Co-reporter:Shuhua He, Xiaozhong Zhou, Zhangpeng Li, Jinqing Wang, Limin Ma, and Shengrong Yang
ACS Applied Materials & Interfaces August 16, 2017 Volume 9(Issue 32) pp:26907-26907
Publication Date(Web):July 26, 2017
DOI:10.1021/acsami.7b07843
The electrochemical properties of the metal–organic framework (MOF)-based composite as electrode material can be significantly improved by means of partial destruction of the full coordination of linkers to metal ions and replacing with other small ions, which make metal centers become more accostable and consequently more effective for the lithiation/delithiation process. In this paper, F– was chosen to replace some of the benzenedicarboxylate (BDC) linkers because of its better interaction with the Li+ than the oxide ion. What’s more, the formed M–F bond promotes the Li+ to transfer at the active material interface and protects the surface from HF attacking. The as-synthesized F-doped Mn-MOF electrode maintains a reversible capacity of 927 mA h g–1 with capacity retention of 78.5% after 100 cycles at 100 mA g–1 and also exhibits a high discharge capacity of 716 mA h g–1 at 300 mA g–1 and 620 mA h g–1 at 500 mA g–1 after 500 cycles. Even at 1000 mA g–1, the electrode still maintains a high reversible capacity of 494 mA h g–1 after 500 cycles as well as a Coulombic efficiency of nearly 100%, which is drastically increased compared with pure Mn-MOF material as expected.Keywords: accessible metal sites; fluorine doping; lithium storage; metal−organic frameworks; varied fluorine contents;
Co-reporter:Peiwei Gong, Jinqing Wang, Kaiming Hou, Zhigang Yang, Zhaofeng Wang, Zhe Liu, Xiuxun Han, Shengrong Yang
Carbon 2017 Volume 112() pp:63-71
Publication Date(Web):February 2017
DOI:10.1016/j.carbon.2016.10.091
Fluorinated graphene quantum dots (FGQDs) have distinctive charge distribution in structure and unique chemical bonds in composition, corresponding to novel performance different from common quantum dots. However, their synthesis is a challenge due to chemically inert CF bonds and hydrophobic nature, and the fluorine influence on FGQDs remains scarce and to be studied. Herein, we first design a gradient fluorine-sacrificing strategy to synthesize FGQDs with controllable sizes and tunable fluorine contents from bulk fluorinated graphite. It is found that although fluorine atom is the second-smallest in periodic table, it not only greatly affects the size formation process, but also endows FGQDs with pH-independent luminescence without any additional surface passivation. And it is for the first time to experimentally observed that point defects in FGQDs induced by fluorine can greatly increase paramagnetism, which is 5 times higher than unfluorinated ones. Moreover, cytotoxicity experiments clearly reveal FGQDs show good biocompatibility, and it is the chemical surface rather than size that influences the cell viability. This work realizes fine control over both structure and chemistry of FGQDs, and thus allows a better insight into the fluorine effects on formation and performance of graphene quantum dots.
Co-reporter:Ping Wen, Chaoyang Zhang, Zhigang Yang, Rui Dong, Dongmei Wang, Minjing Fan, Jinqing Wang
Tribology International 2017 Volume 111(Volume 111) pp:
Publication Date(Web):1 July 2017
DOI:10.1016/j.triboint.2017.02.044
•Triazine-based covalent-organic frameworks (TriCF) was synthesized as a novel lubricant additive.•TriCF exhibited the lamellar structure feature and excellent dispersity in PAO-10 base oil.•The tribological tests demonstrated that TriCF show great friction-reduction and anti-wear performance.•The lamellar structure and strong affinity from matrix make intense contributions for excellent tribological performance.Triazine-based covalent-organic frameworks (TriCF) has been prepared successfully through a facile solvothermal reaction and applied to evaluate the tribological performances as lubricant additive. TriCF exhibited the lamellar structure feature and high thermo-stability, and pictured the excellent dispersity in poly-alpha-olefin-10 oil. The tribological tests demonstrated that adding 0.6 wt% TriCF into PAO-10 oil can great reduce coefficient of friction and volume of wear for steel-steel system, while 0.2 wt% TriCF was perfectly competent for steel-copper system. The analysis of worn surface revealed that the lamellar structure was crux to ensure the TriCF easy slide during the sliding process, reducing the coefficient of friction. The strong affinity from matrix can avoid the cracking-off of protective film, supporting the running stability.Download high-res image (252KB)Download full-size image
Co-reporter:Hong Yuan, Shengrong Yang, Xiaohong Liu, Zhaofeng Wang, Limin Ma, Kaiming Hou, Zhigang Yang, Jinqing Wang
Composites Part A: Applied Science and Manufacturing 2017 Volume 102(Volume 102) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.compositesa.2017.07.013
In this work, we report a facile and efficient approach to overcome the poor dispersion of MoS2 nanoflowers in polyimide (PI) by carefully grafting them onto the surface of hollow carbon nanofibers (HCNF). The obtained MoS2@HCNF hybrid was then utilized as homogeneous filler to enhance the tensile strength and lubricity of the PI-based protective coating. The results revealed that the tensile strength can be effectively improved by 46% accompanying with a slight decrease in elongation (19%) after the incorporation of 2.0 wt% MoS2@HCNF. Furthermore, the MoS2@HCNF/PI composite coatings also manifested outstanding anti-wear and friction reduction characteristics under the lubrication conditions of water (0.5 wt%, 72.5% reduction in wear rate) and liquid paraffin oil (1.5 wt%, 56% reduction in wear rate), demonstrating that the formed stable MoS2@HCNF hybrid could collaboratively alleviate the wear caused by the friction shear force in PI matrix through water or oil medium. The outstandingly enhanced behaviors of MoS2@HCNF hybrid suggest its potential application as the novel filler in anti-wear composite coatings.
Co-reporter:Shuhua He;Zhangpeng Li;Limin Ma;Jinqing Wang;Shengrong Yang
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 23) pp:14209-14216
Publication Date(Web):2017/11/20
DOI:10.1039/C7NJ02846F
Herein, Mn-MOF/RGOn composites have been successfully synthesized using terephthalic acid non-covalent functionalized graphene oxide (GO) sheets acting as efficient nucleation sites and structure-directing templates to direct the growth of MOFs. The electrochemical performance of the Mn-MOF/RGOn composite electrode was much better than that of the pristine Mn-MOF when used as a candidate anode material for lithium-ion batteries due to the synergetic advantages of RGO and Mn-MOF, improved electrical conductivity, and mechanical flexibility of Mn-MOF. Especially, the Mn-MOF/RGO10 composite electrode maintains a reversible discharge capacity of 715 mA h g−1 with a capacity retention of 98% after 100 cycles at 100 mA g−1 and also exhibits a high discharge capacity of 485 mA h g−1 at 300 mA g−1, 432 mA h g−1 at 500 mA g−1 while still maintaining 348 mA h g−1 at 1000 mA g−1 after 500 cycles, which is greatly higher as compared to that of the pure Mn-MOF material as expected.
Co-reporter:Tianhua Sun;Xiaohong Liu;Zhangpeng Li;Limin Ma;Jinqing Wang;Shengrong Yang
New Journal of Chemistry (1998-Present) 2017 vol. 41(Issue 15) pp:7142-7150
Publication Date(Web):2017/07/24
DOI:10.1039/C7NJ00623C
Layered transition metal dichalcogenides (TMDs) have attracted widespread attention for developing electrochemical energy storage due to their unique graphite-like structure and high theoretical capacity. However, the semiconductor character of TMDs affects their electrical conductivity, causing low specific capacitance, rapid capacity fading and poor cyclic stability. Herein, a hierarchical graphene-wrapped CNT@MoS2 (CMG) electrode material has been fabricated aiming at enhancing the conductivity and structural stability during continuous charge–discharge processes, thus improving its electrochemical properties. As a novel electrode material, the prepared CMG electrode delivers a high specific capacitance of 498 F g−1 and excellent long-term cycle-life stability (only 5.7% loss of its initial capacitance after 10 000 cycles at a high current density of 5 A g−1), as well as improved rate performance, indicating that such a composite material is an ideal electrode material for supercapacitors. Its outstanding electrochemical performance can be ascribed to an expanded interlayer spacing of MoS2 and its unique hierarchical architecture. More importantly, this method can be readily extended to the construction of other TMD-based electrodes which were hampered in electrochemical applications owing to their poor electrical conductivity.
Co-reporter:Tianhua Sun, Zhangpeng Li, Xiaohong Liu, Limin Ma, Jinqing Wang, Shengrong Yang
Journal of Power Sources 2017 Volume 352(Volume 352) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.jpowsour.2017.03.123
•O-MoS2 microspheres with tunable interiors are prepared by hydrothermal method.•O-MoS2 microspheres possess the enlarged interlayer spacing along c-axis.•O-MoS2 microspheres are used as electrode materials for supercapacitors.•High specific capacitance and cycling stability are achieved.In this work, a simple and facile one-step hydrothermal method is developed to synthesize oxygen-incorporated molybdenum disulphide (O-MoS2) microspheres with tunable interiors (solid, yolk-shell and hollow microstructures) by using carbon disulfide (CS2) as soft template and sulfur source simultaneously. The synthesized O-MoS2 microspheres with enlarged interlayer spacing of ca. 9.8 Å show remarkable electrochemical performances as novel electrode materials for supercapacitors (SCs). Specifically, O-MoS2 hollow microsphere exhibits optimal electrochemical performances with a high specific capacitance of 744.2 F g−1 at a current density of 1 A g−1 and a good cycling stability with ca. 77.8% capacitance retention after 10 K continuous charge–discharge cycles at a high current density of 5 A g−1, thus making it a promising electrode material for high-performance SCs. The excellent electrochemical performances are mainly attributed to the enlarged interlayer spacing and the reduced band gap owing to the oxygen incorporation in MoS2 and the hollow microstructure.Download high-res image (234KB)Download full-size image
Co-reporter:Xiangyuan Ye, Limin Ma, Zhigang Yang, Jinqing Wang, Honggang Wang, and Shengrong Yang
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 11) pp:7483
Publication Date(Web):February 29, 2016
DOI:10.1021/acsami.5b10579
Although the fluorinated graphene (FG) possesses numerous excellent properties, it can not be really applied in aqueous environments due to its high hydrophobicity. Therefore, how to achieve hydrophilic FG is a challenge. Here, a method of solvent-free urea melt synthesis is developed to prepare the hydrophilic urea-modified FG (UFG). Some characterizations via transmission electron microscopy (TEM), atomic force microscopy (AFM), Fourier transfer infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), and thermo gravimetric analysis (TGA) demonstrate that the urea molecules can covalently functionalize the FG and the hydrophilic UFG can be prepared. According to the tribological tests run on an optimal-SRV-I reciprocation friction tester, it can be found that the antiwear ability of water can be largely improved by adding the appropriate UFG. When the concentration of UFG aqueous dispersion is 1 mg/mL, the sample of UFG-1 has the best antiwear ability with a 64.4% decrease of wear rate compared with that of the pure water (UFG-0), demonstrating the prepared UFG can be used as a novel and effective water-based lubricant additive.Keywords: fluorinated graphene (FG); friction; functionalization; hydrophilicity; water-based lubricant additive; wear
Co-reporter:Dingjun Zhang, Jiechang Gao, Zhangpeng Li, Shuhua He and Jinqing Wang
RSC Advances 2016 vol. 6(Issue 60) pp:54880-54888
Publication Date(Web):27 May 2016
DOI:10.1039/C6RA04052G
Porous carbon materials have greatly developed as promising electrode materials for electric double-layer capacitors (EDLCs). Herein, hierarchically porous carbon spheres (HPCSs) were synthesized by using chitosan, glutaraldehyde and KOH as the carbon source, crosslinking agent and chemical activating agent, respectively. The morphology of the HPCSs was characterized by scanning electron microscopy and transmission electron microscopy, while the porous structural features, including high specific surface area (1974 m2 g−1), total pore volume (2.52 cm3 g−1) and wide pore-size distribution, were measured by nitrogen sorption technology. Electrochemical tests in a three-electrode cell indicated that the prepared HPCSs displayed excellent capacitive performances (328 F g−1), and good cycling stability with approximately 9% of capacitance reduction after 10000 times of cycling. Moreover, the electrochemical properties characterized in a two-electrode system indicated that the specific capacitance is 66.1 F g−1 at a current density of 0.5 A g−1, and the energy density is 8.3 W h kg−1 at a power density of 6 kW kg−1, demonstrating that the obtained HPCSs are a potential electrode material and met well the practical requirement for an EDLC.
Co-reporter:Shuhua He, Zhangpeng Li, Jinqing Wang, Ping Wen, Jiechang Gao, Limin Ma, Zhigang Yang and Shengrong Yang
RSC Advances 2016 vol. 6(Issue 55) pp:49478-49486
Publication Date(Web):06 May 2016
DOI:10.1039/C6RA03992H
NixCo1−x(OH)2 composite microspheres with uniform sizes are successfully synthesized with the assistance of alkali solution by employing a bimetallic Co–Ni–metal organic framework (Co–Ni–MOF) as both the precursor and the self-sacrificing template. The as-obtained NixCo1−x(OH)2 composite demonstrates excellent electrochemical performance, including a high specific capacitance of 1235.9 F g−1 at a current density of 0.5 A g−1, good electrochemical stability, with ∼73% retention of its initial capacitance after 10000 cycles, and a high rate capability; this composite exhibits great application prospects as a novel electrode material for supercapacitors.
Co-reporter:Ping Wen, Zhangpeng Li, Peiwei Gong, Jinfeng Sun, Jinqing Wang and Shengrong Yang
RSC Advances 2016 vol. 6(Issue 16) pp:13264-13271
Publication Date(Web):22 Jan 2016
DOI:10.1039/C5RA27893G
A reduced graphene oxide/carbonized metal–organic framework (rGO/CMOF-5) hybrid with an rGO inner layer and an outer cover of CMOF-5 was successfully fabricated by combining a simple solvothermal reaction with an annealing treatment. The resulting rGO/CMOF-5 hybrid had a high specific surface area (2040 m2 g−1) and a reasonable porous structure and showed improved electrochemical performance when used as a novel supercapacitor electrode material. Electrochemical tests showed that the rGO/CMOF-5 hybrid achieved an impressive specific capacitance of 312 F g−1 at a current density of 0.5 A g−1 in an alkaline electrolyte and an outstanding cycle stability (retaining 89% capacitance after 5000 cycles) and favorable rate capability with 59% retention after a 40-fold increase. A symmetrical supercapacitor based on the rGO/CMOF-5 hybrid delivered a high energy density of 17.2 W h kg−1 at a power density of 250 W kg−1 and retained 81% of its initial capacitance at a current density of 2 A g−1 after 5000 charge–discharge cycles. These results indicate that this hybrid could be used in electrochemical energy storage and gave new insights into the design and utilization of aged carbon materials with remarkable performances.
Co-reporter:Xiangyuan Ye, Xiaohong Liu, Zhigang Yang, Zhaofeng Wang, Honggang Wang, Jinqing Wang, Shengrong Yang
Composites Part A: Applied Science and Manufacturing 2016 Volume 81() pp:282-288
Publication Date(Web):February 2016
DOI:10.1016/j.compositesa.2015.11.029
The tribological properties of polyimide (PI) and PI/fluorinated graphene (FG) nanocomposites, as a new class of graphene reinforced polymer, are investigated using a ball-on-disk configuration under different lubricated conditions of dry sliding, water lubrication and oil lubrication. Experimental results reveal that single incorporation of FG can effectively improve the tribological performance of PI under all the three conditions. In addition, compared to the results under dry sliding, the phenomenon that the friction coefficient decreases while the wear rate increases under water lubrication condition is observed and researched in detail. The worst anti-wear performance under water-lubricated condition can be ascribed to the fact that the water can be adsorbed by the polar imide radicals of the PI and PI/FG nanocomposite, therefore leading to the property deterioration of the PI and PI/FG nanocomposite coatings.
Co-reporter:Wei Hong, Jinqing Wang, Zhangpeng Li and Shengrong Yang
Journal of Materials Chemistry A 2015 vol. 3(Issue 6) pp:2535-2540
Publication Date(Web):25 Nov 2014
DOI:10.1039/C4TA04707A
We have successfully fabricated hybrid Co3O4@Au-decorated PPy core/shell nanowire arrays (NWAs) on Ni foam via in situ interfacial polymerization between HAuCl4 and pyrrole monomers. With the advantages of high electrochemical activity of each component and high electrical conductivity of the Au-decorated PPy layer, this hybrid electrode exhibits remarkable pseudo-capacitive behaviors. This facile synthesis method offers an attractive strategy to further improve the electrochemical performance of pseudo-capacitors, and it undoubtedly shows promising applications in electrochemical energy storage.
Co-reporter:Ping Wen, Peiwei Gong, Jinfeng Sun, Jinqing Wang and Shengrong Yang
Journal of Materials Chemistry A 2015 vol. 3(Issue 26) pp:13874-13883
Publication Date(Web):22 May 2015
DOI:10.1039/C5TA02461G
Currently, metal–organic frameworks (MOFs) have been attracting great interest as a new kind of electrode material for energy storage devices, because their porous skeleton would benefit the access and transport of electrolytes, and the exposure of metal ions can offer more active sites to electrolytes. In this study, we have successfully fabricated nickel metal–organic framework/carbon nanotube (Ni-MOF/CNT) composites, which show excellent electrochemical performance due to the synergistic effects of the Ni-MOF specific structure and CNTs with high conductivity, achieving a high specific capacitance of 1765 F g−1 at a current density of 0.5 A g−1. To further explore the capacitive performance of the composite electrode, an asymmetric supercapacitor device using Ni-MOF/CNTs as the positive electrode and reduced graphene oxide/graphitic carbon nitride (rGO/g-C3N4) as the negative electrode was fabricated, and this device could be operated in a working voltage range of 0–1.6 V based on a complementary potential window in 6 M KOH aqueous electrolyte, delivering a high energy density of 36.6 W h kg−1 at a power density of 480 W kg−1. Moreover, this asymmetric supercapacitor revealed an excellent cycle life along with 95% specific capacitance retention after 5000 consecutive charge–discharge tests. These outstanding performances would make MOFs become one of the most promising candidates for the future high energy storage systems.
Co-reporter:Peiwei Gong, Zhigang Yang, Wei Hong, Zhaofeng Wang, Kaiming Hou, Jinqing Wang, Shengrong Yang
Carbon 2015 Volume 83() pp:152-161
Publication Date(Web):March 2015
DOI:10.1016/j.carbon.2014.11.027
Water-soluble and blue luminescent graphene fluoroxide quantum dots (GFOQDs) with tunable fluorine coverage and size were effectively synthesized from exfoliated fluorinated graphene (FG) by sacrificing certain fluorine to improved solubility and reaction activity. Morphology investigation indicates that the obtained GFOQDs possess narrow size distribution and the average size is 2.5–3.5 nm. Chemical composition analysis confirms that besides C–F covalent bonds, C–O bonds in the forms of hydroxyl and carbonyl co-exist on the structure of GFOQDs. Moreover, photoluminescence performance research considering the surface state and size has also been conducted, and as anticipated in carbon-based quantum dots the GFOQDs exhibit excitation wavelength-dependent properties. Additionally, rather different from other graphene quantum dots (GQDs) that are often susceptible to pH without additional surface passivation, the GFOQDs themselves are poised to resist pH effects and display stable luminescence in both acid and alkali conditions. These results indicate that our method not only opens up a new avenue to prepare GQDs decorated with fluorine and oxygen, but also can find practical applications in novel GQDs-based devices that require water solubility while keep chemical stability and resistance against pH.
Co-reporter:Guoying Bai, Jinqing Wang, Zhigang Yang, Honggang Wang, Zhaofeng Wang, Shengrong Yang
Carbon 2015 Volume 84() pp:197-206
Publication Date(Web):April 2015
DOI:10.1016/j.carbon.2014.11.063
In this work, we report a simple self-assembly way to prepare ceria/graphene oxide (CeO2/GO) composite films on silicon (Si) substrates, which exhibit significant enhancement on tribological performances compared with Si substrates and GO films. Specifically, the friction coefficient is reduced drastically to the one-third of that of Si substrates. What’s more, the antiwear lifetime is markedly prolonged to ∼8 h under a high applied load of 2 N, which is over seven times longer than that of GO films. It is expected that the CeO2/GO composite films may find wide applications in nano/microelectromechanical systems as high-performance solid lubricating films, due to their facile and low cost preparation, nano-scale thickness, lower friction coefficient and desired antiwear lifetime.
Co-reporter:Zengjie Fan, Qianqian Lin, Peiwei Gong, Bin Liu, Jinqing Wang, Shengrong Yang
Electrochimica Acta 2015 Volume 151() pp:186-194
Publication Date(Web):1 January 2015
DOI:10.1016/j.electacta.2014.11.022
Enzymatic loss and inactivation are two main problems which can affect the performance of the biosensor. In order to resolve these two problems, a new kind of enzymatic biosensor for the amperometric detection of hydrogen peroxide (H2O2) was developed using biomimetic graphene capsules (GRCAPS). Horseradish peroxidase was initially encapsulated in GRCAPS using porous CaCO3 as sacrificial templates to mimic the existence form of bio-enzymes in the organisms, and then GRCAPS and graphene-poly(sodium 4-styrenesulfonate) were alternatively assembled onto the substrate of indium tin oxide for constructing multilayer films of the biosensor. Transmittance electron microscopy and field-emission scanning electron microscopy analyses proved that the GRCAPS and multilayer films were prepared. Electrochemical experiment results indicated that easy, direct electrochemistry and good catalytic activity toward H2O2 oxidation can be achieved with this biosensor. The resulting biosensor presented a wide linear range of 0.01–12 mmol l−1, a low detection limit of 3.3 μmol l−1 (S/N = 3), excellent anti-interference ability, and long-term stability as well.
Co-reporter:Jinfeng Sun, Zhangpeng Li, Jinqing Wang, Wei Hong, Peiwei Gong, Ping Wen, Zhaofeng Wang, Shengrong Yang
Journal of Alloys and Compounds 2015 Volume 643() pp:231-238
Publication Date(Web):15 September 2015
DOI:10.1016/j.jallcom.2015.04.137
•Ni(OH)2/GS and Bi2O3/GS composite were synthesized respectively by simple methods.•A novel Ni/Bi battery is assembled using Ni(OH)2/GS and Bi2O3/GS as electrode materials.•The Ni/Bi battery exhibits a high capacity of 98 mA h g−1 at 1 C and energy density of 82.6 W h kg−1.Two kinds of graphene-based composite materials of Ni(OH)2 nanoparticles/graphene sheets (Ni(OH)2/GS) and Bi2O3 rods/graphene sheets (Bi2O3/GS) were respectively synthesized by chemical bath deposition. Morphological and structural analysis by field-emission scanning electron microscopy, transmission electron microscope, X-ray diffraction and X-ray photoelectron spectroscopy confirmed the successful composite of GS with the metal compounds. Then, a high performance Ni/Bi battery was designed and fabricated using the Bi2O3/GS hybrid material as negative electrode and Ni(OH)2/GS as positive electrode. As a result, this Ni/Bi battery delivers a high discharge capacity of 102 mA h g−1 at 1 C and good rate capability. A high energy density of 83.2 W h kg−1 is also achieved at a power density of 143 W kg−1 and can still maintain a high level of 60.1 W h kg−1 at 2609 W kg−1, illustrating that this Ni/Bi battery is a promising candidate as energy storage devices.
Co-reporter:Xiangyuan Ye, Jinqing Wang, Honggang Wang, Shengrong Yang
Microporous and Mesoporous Materials 2015 Volume 204() pp:131-136
Publication Date(Web):1 March 2015
DOI:10.1016/j.micromeso.2014.11.020
•Mesoporous silica nanospheres (MSNs) with uniform pore diameter are synthesized.•MSNs are employed as the container of lubricating oil for the first time.•MSNs containing liquid paraffin can greatly reduce the friction and wear.Mesoporous silica nanospheres (MSNs), with neat morphology, large Brunauer–Emmett–Teller (BET) surface area and uniform pore diameter, have been synthesized firstly, and then the liquid paraffin as lubricating oil is poured into the pores of the MSNs via a simple wet impregnation method to form paraffin-containing MSNs (abbreviated as PMSNs). The tribological tests are carried out under three different loads (1.0, 1.5, and 2.0 N) by sliding a steel ball (φ = 6 mm) against PMSNs thin films spin-coated on glass slides. The results indicate that the friction coefficient of glass slide reduces greatly from 0.7 to 0.09 due to the effective release of liquid paraffin preserved inside the pores of MSNs under these loads. Meantime, the corresponding wear volumes of glass slides also decrease greatly after the formation of the PMSNs film. As a result, the present work lights a pharos to utilize lubricating oil more effectively via releasing oil preserved inside the pores of the MSNs.
Co-reporter:Qi Zhou, Jingxia Huang, Jinqing Wang, Zhigang Yang, Sheng Liu, Zhaofeng Wang and Shengrong Yang
RSC Advances 2015 vol. 5(Issue 111) pp:91802-91812
Publication Date(Web):12 Oct 2015
DOI:10.1039/C5RA17440F
Nanocomposites consisting of zirconia (ZrO2) nanoparticles and reduced graphene oxide (rGO) nanosheets were successfully fabricated by a one-pot hydrothermal method. By regulating the proportion of the precursors of the GO colloidal suspension and zirconium oxychloride (ZrOCl2) solution, ZrO2 nanoparticles with a diameter of about 5 nm were uniformly anchored onto the rGO nanosheets. The combination mechanism of ZrO2 nanoparticles fully bonded onto rGO nanosheets is the formation of the monodentate or bidentate composites between the oxygen-containing groups of GO and Zr(IV) complex ions from hydrolysis of the ZrOCl2 solution. The dispersibility and tribological properties of the prepared composites were investigated as novel lubricant additives in paraffin oil. The results suggested that the oil with a small amount of nanocomposite (0.06 wt%) exhibits good dispersibility, excellent friction-reduction and anti-wear properties as well as a high load-bearing capacity caused by the synergistic effect of the rGO nanosheets and ZrO2 nanoparticles.
Co-reporter:Jinfeng Sun, Jinqing Wang, Zhangpeng Li, Zhigang Yang and Shengrong Yang
RSC Advances 2015 vol. 5(Issue 64) pp:51773-51778
Publication Date(Web):05 Jun 2015
DOI:10.1039/C5RA09760F
Three dimensional (3D) hierarchical structures have attracted rapidly increasing attention in the energy storage field because they can facilitate electron and ion transport and electrolyte/electrode contact which results in full utilization of active materials. Here, a series of 3D hierarchical bismuth (Bi)-based compounds with different sizes and morphologies have been controllably synthesized by adjusting the Bi3+/urea molar ratio. Electrochemical characterizations indicated that the prepared Bi-based compounds exhibit high specific capacitance and superior rate capability in aqueous alkaline electrolyte (832 F g−1 at 1 A g−1, and still maintained 90% of the initial level at 20 A g−1), which can be attributed to their novel hierarchical structure.
Co-reporter:Peiwei Gong, Kaiming Hou, Xiangyuan Ye, Limin Ma, Jinqing Wang, Shengrong Yang
Materials Letters 2015 Volume 143() pp:112-115
Publication Date(Web):15 March 2015
DOI:10.1016/j.matlet.2014.12.058
•Bulk fluorinated graphite is effectively transformed into fluorescent fluorinated graphene quantum dots by a designed exfoliation and cutting process.•The fluorine contents and sizes of the obtained fluorinated graphene quantum dots can be tuned by adjusting the reaction conditions.•The obtained fluorinated graphene quantum dots exhibit uniform size, enjoy good solubility in water and display brightly blue emission.•Thin and transparent fluorinated graphene sheets can also be readily obtained by our method.Synthesizing fluorinated graphene quantum dots (FGQDs) has been a great challenge due to the chemically inert C-F bond, and few attempts have been made to prepare this material. In this article, a novel, mild and effective method to controllably prepare FGQDs with tunable fluorine coverage and size by employing commercial fluorinated graphite is developed. This method avoids the complex procedures of preparing fluorinated graphene and use of toxic gases, and can be realized under mild conditions. Moreover, the obtained FGQDs possess relatively uniform size, enjoy good solubility and stability in water and exhibit highly bright blue luminescence.
Co-reporter:Xiangyuan Ye, Peiwei Gong, Jinqing Wang, Honggang Wang, Sili Ren, Shengrong Yang
Composites Part A: Applied Science and Manufacturing 2015 Volume 75() pp:96-103
Publication Date(Web):August 2015
DOI:10.1016/j.compositesa.2015.04.005
In order to explore the addition effect of fluorinated graphene (FG) on the mechanical and thermal performances of polyimide (PI) matrix, FG sheets are first prepared and employed as the nanofillers to construct PI/FG nanocomposite films. The prepared film is optically transparent at low content of FG and experimental results demonstrate that the addition of FG can effectively enhance the properties of PI matrix. Especially, compared with pure PI matrix, the addition of 0.5 wt% FG in PI can endow 30.4% increase in tensile stress and 115.2% increase in elongation at break. Experimental analyses considering the morphology and microstructure are also conducted, and the results indicate that the improved mechanical properties of the PI/FG nanocomposite films are mainly attributed to the good dispersibility of FG sheets in PI host, and the effective stress transfer between the polymer and the FG.
Co-reporter:Zhangpeng Li;Hongtao Xue; Jinqing Wang;Yongbing Tang; Chun-Sing Lee; Shengrong Yang
ChemElectroChem 2015 Volume 2( Issue 11) pp:1682-1686
Publication Date(Web):
DOI:10.1002/celc.201500179
Abstract
We report a graphene/cobalt selenide (rGO/CoSe2) composite as an anode material for lithium-ion batteries. The prepared composite shows a wrinkled morphology with the CoSe2 nanoparticles tightly anchored/wrapped on/in the rGO sheets. The rGO/CoSe2 composite exhibits enhanced electrochemical performance with higher capacity, better rate capability, and cycling performance compared to pure CoSe2. The rGO/CoSe2 composite delivers a high initial reversible capacity of 726 mAh g−1 and a very high capacity of 1577 mAh g−1 after 200 cycles at a current density of 200 mA g−1 (0.38 C). The rGO sheets in the composite play important roles for the improvement in electrochemical properties, for example, the rGO sheet not only enhances the electrical conductivity of the whole electrode, but also alleviates the structure degradation caused by volume expansion of CoSe2 during discharge/charge processes, resulting in improved lithium-storage performances.
Co-reporter:Zengjie Fan;Bin Liu;Jinqing Wang;Songying Zhang;Qianqian Lin;Peiwei Gong;Limin Ma;Shengrong Yang
Advanced Functional Materials 2014 Volume 24( Issue 25) pp:3933-3943
Publication Date(Web):
DOI:10.1002/adfm.201304202
Avoiding wound infection and retaining an appropriate level of moisture around woundz are major challenges in wound care management. Therefore, designing hydrogels with desired antibacterial performance and good water-maintaining ability is of particular significance to promote the development of wound dressing. Thus a series of hydrogels are prepared by crosslinking of Ag/graphene composites with acrylic acid and N,N′-methylene bisacrylamide at different mass ratios. The antibacterial performance and accelerated wound-healing ability of hydrogel are systematically evaluated with the aim of attaining a novel and effective wound dressing. The as-prepared hydrogel with the optimal Ag to graphene mass ratio of 5:1 (Ag5G1) exhibits stronger antibacterial abilities than other hydrogels. Meanwhile, Ag5G1 hydrogel exhibits excellent biocompatibility, high swelling ratio, and good extensibility. More importantly, in vivo experiments indicate that Ag5G1 hydrogel can significantly accelerate the healing rate of artificial wounds in rats, and histological examination reveals that it helps to successfully reconstruct intact and thickened epidermis during 15 day of healing of impaired wounds. In one word, the present approach can shed new light on designing of antibacterial material like Ag/graphene composite hydrogel with promising applications in wound dressing.
Co-reporter:Peiwei Gong, Jinqing Wang, Weiming Sun, Di Wu, Zhaofeng Wang, Zengjie Fan, Honggang Wang, Xiuxun Han and Shengrong Yang
Nanoscale 2014 vol. 6(Issue 6) pp:3316-3324
Publication Date(Web):02 Jan 2014
DOI:10.1039/C3NR05725A
Tunable control over the functionalization of graphene is significantly important to manipulate its structure and optoelectronic properties. Yet the chemical inertness of this noble carbon material poses a particular challenge for its decoration without forcing reaction conditions. Here, a mild, operationally simple and controllable protocol is developed to synthesize hydroxylated graphene (HOG) from fluorinated graphene (FG). We successfully demonstrate that under designed alkali environment, fluorine atoms on graphene framework are programmably replaced by hydroxyl groups via a straightforward substitution reaction pathway. Element constituent analyses confirm that homogeneous C–O bonds are successfully grafted on graphene. Rather different from graphene oxide, the photoluminescence (PL) emission spectrum of the obtained HOG becomes split when excited with UV radiation. More interestingly, such transformation from FG facilitates highly tunable PL emission ranging from greenish white (0.343, 0.392) to deep blue (0.156, 0.094). Additionally, both experimental data and density function theory calculation indicate that the chemical functionalization induced structural rearrangement is more important than the chemical decoration itself in tuning the PL emission band tail and splitting energy gaps. This work not only presents a new way to effectively fabricate graphene derivatives with tunable PL performance, but also provides an enlightening insight into the PL origin of graphene related materials.
Co-reporter:Peiwei Gong, Zhaofeng Wang, Zengjie Fan, Wei Hong, Zhigang Yang, Jinqing Wang, Shengrong Yang
Carbon 2014 Volume 72() pp:176-184
Publication Date(Web):June 2014
DOI:10.1016/j.carbon.2014.01.070
Fluorine and oxygen co-doped graphene with controllable element coverage was effectively synthesized through simultaneously fluorinating and reducing graphene oxide by pyrolysis of fluorinated graphite. Morphology investigation indicates that the doped graphene is of few-layered thickness, and the prepared films exhibit layered structure through cross-section. Chemical composition analysis confirms that fluorine has been grafted onto graphene scaffold through CF covalent bond, and the doping level can be readily manipulated just by adjusting the reaction temperature. The structural changes of graphene induced by the controllable doping thus facilitate the tunable electrical property, which can be tuned over several orders of magnitude. These results indicate our method is not only potentially useful to tailor the chemical surface and electronic structure of graphene, but also can find applications in novel electronic devices based on graphene co-doped with different dopants.
Co-reporter:Zengjie Fan, Jinqing Wang, Zhaofeng Wang, Haiqiong Ran, Yang Li, Lengyuan Niu, Peiwei Gong, Bin Liu, Shengrong Yang
Carbon 2014 Volume 66() pp:407-416
Publication Date(Web):January 2014
DOI:10.1016/j.carbon.2013.09.016
This paper presents a convenient one-pot hydrothermal strategy for the synthesis of graphene nanosheet (GNS)/hydroxyapatite (HA) nanorod composites (GNS/HA). Characterization of GNS/HA nanorod composites denote that rod-like HA, which has an average length of 55 nm and diameter of 13 nm, anchors on both sides of GNS. Introducing graphene can effectively improve the hardness and Young’s modulus of HA. The synthesized GNS/HA nanorod composite containing 40 wt.% HA shows higher osseointegration ability with surrounding tissues, better biocompatibility, and more superior bone cellular proliferation induction than pristine graphene oxide and HA do. The biocompatibility of GNS/HA nanorod composite makes it a promising candidate for bone regeneration and implantation.
Co-reporter:Lengyuan Niu, Jinqing Wang, Wei Hong, Jinfeng Sun, Zengjie Fan, Xiangyuan Ye, Honggang Wang, Shengrong Yang
Electrochimica Acta 2014 Volume 123() pp:560-568
Publication Date(Web):20 March 2014
DOI:10.1016/j.electacta.2014.01.005
•Ni/RGO composites were successfully synthesized through a simple solvothermal method.•The attached Ni nanoparticles can efficiently inhibit the aggregation of RGO nanosheets and provide pseudocapacitance.•Ni/RGO–2 exhibits the highest specific capacitance of 547.3 F g−1 at 1 A g−1 in 2 M KOH.•Ni/RGO–2 can maintain 81% of initial capacity after a continuous 1000 times of cycling.A series of Ni/reduced graphene oxide (Ni/RGO) composites were synthesized through a simple solvothermal method. Detailed characterizations of the composite using transmission electron microscopy and field emission scanning electron microscopy indicated that Ni particles were uniformly dispersed on the RGO surfaces. The electrochemical performances of Ni/RGO composites were much higher than their counterparts of Ni and RGO, because of the Ni particles being firmly decorated with the RGO nanosheets and the synergistic effect between both components. Among the prepared composites, Ni/RGO–2 exhibits the best electrochemical performance; namely, a high specific capacitance of 547.3 F g−1 is obtained in 2 M KOH at 1 A g−1 and 81% of initial value is remained after a continuous cycling of 1000 times, which make it to be a promising electrode material for supercapacitors.
Co-reporter:Wei Hong, Jinqing Wang, Lengyuan Niu, Jinfeng Sun, Peiwei Gong, Shengrong Yang
Journal of Alloys and Compounds 2014 Volume 608() pp:297-303
Publication Date(Web):25 September 2014
DOI:10.1016/j.jallcom.2014.04.131
•Smartly designed 3D CoAl LDH@Ni(OH)2 NSAs have been successfully synthesized.•This hierarchical electrode represents enhanced supercapacitive performance.•The synergy and structural features account for the enhanced capacitive properties.Electrodes with novel hierarchical nanoarchitectures can offer many opportunities for achieving the enhanced performance in energy storage. Herein, we have designed and synthesized 3D hierarchical structures of CoAl LDH@Ni(OH)2 nanosheet arrays (NSAs) by a facile two-step route. Compared with the pristine CoAl LDH NSAs, the hierarchical CoAl LDH@Ni(OH)2 NSAs represents much better capacitive behaviors. Specifically, under the same test conditions, CoAl LDH@Ni(OH)2 electrode exhibits the maximum specific capacitance of 1528 F g−1 (by galvanostatic discharge at the current density of 5 mA cm−2 in 2 M KOH, based on the total mass; that for CoAl LDH NSAs is only 738 F g−1) and excellent cycling performance (retaining 92% of its original capacitance after 1300 times of cycling). Such enhanced supercapacitor performances can be attributed to the novel 3D architectures, which can benefit the full contact of the Ni(OH)2 layer with OH− in the electrolyte.
Co-reporter:Kaiming Hou, Peiwei Gong, Jinqing Wang, Zhigang Yang, Zhaofeng Wang and Shengrong Yang
RSC Advances 2014 vol. 4(Issue 100) pp:56543-56551
Publication Date(Web):21 Oct 2014
DOI:10.1039/C4RA10313K
The high strength and noble inertness of fluorinated graphene (FG) indicate very promising properties for its application in tribological applications to reduce friction and save energy, yet few works refer to its tribological performance, mostly due to the lack of an effective synthesis method and limited knowledge of FG. In this work, fluorinated graphene (FG) sheets with various fluorine contents are prepared from fluorinated graphite (FGi) by means of controllable chemical reaction with ethylenediamine (EDA) and liquid-phase exfoliation with N-methyl-2-pyrrolidone (NMP) in a one-pot synthesis. Transmission electron microscopy and atomic force microscopy analyses show that the obtained FG sheets possess large lateral size and ultrathin thickness (1.8–4.0 nm). Chemical characterizations indicate the C/F ratio can be readily tuned by adjusting the reaction temperature with EDA, which leads to defluorination and also substitution of a small amount of fluorine atoms by alkylidene amino groups. The tribological performance of FG samples as novel lubricant additives in base oil of polyalphaolefin-40 with different concentrations (0.1–0.4 mg mL−1) is investigated. The tribological tests suggest that the addition of FG at optimum concentration can greatly improve the anti-wear property of the base oil and there exists a strong proportional relationship between anti-wear ability and fluorine content.
Co-reporter:Zhangpeng Li, Jinqing Wang, Zhaofeng Wang, Yongbing Tang, Chun-Sing Lee and Shengrong Yang
RSC Advances 2014 vol. 4(Issue 97) pp:54416-54421
Publication Date(Web):17 Oct 2014
DOI:10.1039/C4RA10338F
A facile strategy is developed to fabricate a MnO2 nanowire/reduced graphene oxide (rGO) hybrid with an interconnected structure. The morphology and microstructure of the hybrid is examined by field emission scanning electron microscopy, transmission electron microscopy, and X-ray diffraction analysis. The electrochemical properties of the MnO2 nanowire as an anode material for lithium-ion batteries are improved by this general strategy involving the addition of rGO sheets to the nanowires, producing a MnO2 nanowires@rGO hybrid (MGH). The rGO effectively buffers the volume changes during the lithiation/delithiation process, allowing the hybrid to retain its structure, without sacrificing its electrochemical performance. As a result, MGH delivers a highly reversible capacity of 1079 mA h g−1 over 200 cycles at a current density of 500 mA g−1, and excellent rate capability, thus such a reasonably stable hybrid exhibits great potential as an anode material for lithium ion batteries.
Co-reporter:Guoying Bai, Jinqing Wang, Zhigang Yang, Honggang Wang, Zhaofeng Wang and Shengrong Yang
RSC Advances 2014 vol. 4(Issue 87) pp:47096-47105
Publication Date(Web):26 Sep 2014
DOI:10.1039/C4RA09488C
Graphene decorated with well-dispersed cubic fluorite ceria (CeO2) nanoparticles was prepared through a simple hydrothermal method. The as-prepared CeO2/graphene composites (COGNCs) were further used as lubricant additives in the base oil of liquid paraffin to investigate their tribological properties by the Optimol SRV-1 oscillating reciprocating friction and wear tests in air (relative humidity, 17%). The results indicated that the introduction of a small amount of COGNCs into the base oil could reduce friction and wear drastically under a high load condition, which was better than the testing results of graphene or CeO2 nanoparticles. Specifically, when 0.06 wt% COGNCs was added into the base oil, the average friction coefficient could be reduced from 0.21 to 0.10, and the wear rate could be decreased to 1.5% of that of base oil. The excellent tribological properties of COGNCs can be explained by the synergistic friction reduction and antiwear effects of graphene and CeO2 nanoparticles.
Co-reporter:Ping Wen, Peiwei Gong, Yongjuan Mi, Jinqing Wang and Shengrong Yang
RSC Advances 2014 vol. 4(Issue 68) pp:35914-35918
Publication Date(Web):25 Jul 2014
DOI:10.1039/C4RA04788E
Graphene sheets with high quality and dispersibility were prepared by exfoliation of edge sulfonated graphite. Tosyl-graphene (TsG) dispersion in N-methyl-pyrrolidone (NMP) readily reached up to 16 mg mL−1 without any surfactants. TsG enjoys intact crystal planes and flexible framework. When employed as electrode material for supercapacitor, TsG shows outstanding specific capacitance of 180 F g−1 at a current density of 0.5 A g−1, and excellent cycling stability (only 2% loss after 10000 cycles), which can offer enormously potential for super-capacitors and other highly desired energy storage devices.
Co-reporter:Zengjie Fan, Bin Liu, Zhangpeng Li, Limin Ma, Jinqing Wang and Shengrong Yang
RSC Advances 2014 vol. 4(Issue 44) pp:23319-23326
Publication Date(Web):08 Apr 2014
DOI:10.1039/C3RA47422D
CuO microstructures with urchin-like, flower-like and sheet-like morphologies were directly grown on a Ni foam via a simple and low-cost hydrothermal method. The aim was to construct a three-dimensional porous hybrid electrode for an amperometric non-enzymatic glucose sensor. As a result, the as-prepared hybrid electrode with a flower-like morphology exhibited a higher electrocatalytic activity towards the oxidation of glucose compared to electrodes with other morphologies and a pristine Ni foam electrode. The flower-like CuO/Ni foam electrode displayed a high sensitivity of 1084 μA mM−1 cm−2 to glucose ranging from 0.5 μM to 3.5 mM, which is higher than most of the reported CuO based electrodes, and also a low detection limit of 0.16 μM (signal/noise = 3). Notably, poisoning by chloride ions and interference from ascorbic acid, uric acid, dopamine, and sucrose were negligible. These results indicate that the flower-like CuO/Ni foam hybrid electrode is a promising candidate for amperometric non-enzymatic glucose detection.
Co-reporter:Yongjuan Mi, Jinqing Wang, Zhigang Yang, Zhaofeng Wang, Honggang Wang and Shengrong Yang
RSC Advances 2014 vol. 4(Issue 12) pp:6060-6067
Publication Date(Web):05 Dec 2013
DOI:10.1039/C3RA46169F
Based on the magic substance dopamine (DA), a simple and effective one-step solution deposition strategy has been developed for constructing high-performance amorphous zirconium oxide (ZrO2) nanocomposite thin film. DA can be auto-polymerized to form a polydopamine (PDA) coating, which adheres strongly to the silicon substrate and serves as an active platform to induce the subsequent deposition of ZrO2. The obtained ZrO2 nanocomposite thin films with the thickness of about one hundred nanometers presents outstanding mechanical and tribological performances even without a subsequent high-temperature annealing process. More importantly, the preparation process is definitely low-consumption and environmentally friendly. This work overcomes the claim that ZrO2 films obtained by aqueous solution deposition process generally possess low mechanical properties and thus avoid the defects of focusing mainly on nature and performances of heat-treated and crystalline ZrO2. Based on this work, it is believed that the as-deposited ZrO2 nanocomposite film can be widely used as a protecting coating and lubricating material for micro- and nano-electromechanical systems (MEMS/NEMS) and many other systems working in similar conditions.
Co-reporter:Xiangyuan Ye;Jinqing Wang;Ye Xu;Lengyuan Niu;Zengjie Fan;Peiwei Gong;Limin Ma;Honggang Wang;Zhigang Yang;Shengrong Yang
Journal of Applied Polymer Science 2014 Volume 131( Issue 23) pp:
Publication Date(Web):
DOI:10.1002/app.41173
ABSTRACT
Series of polyimide (PI)/mesoporous silica nanospheres (MSNs) nanocomposite films with different contents of MSNs were successfully prepared via a simple wet impregnation method. The morphologies, microstructures, mechanical properties, transmittance, and thermal properties of the prepared PI and the PI/MSNs nanocomposite films were investigated in detail. As a result, the thermal stability and mechanical performances of PI were obviously improved by incorporating MSNs into PI. The tensile stress and Young's modulus of the nanocomposite film with 5 wt % MSNs were raised up to 97.65 MPa and 2220.06 MPa, which are greatly higher than the values of 82.51 MPa and 1440.86 MPa for the pure PI film. Experimental results confirmed that the designed polymerization tactic, which occurred in the pores of the MSNs, facilitated to enhance the mechanical and physical performances of the PI/MSNs nanocomposite films, and definitely induced better integration between organic matrix and inorganic nanofillers. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41173.
Co-reporter:Lengyuan Niu, Zhangpeng Li, Ye Xu, Jinfeng Sun, Wei Hong, Xiaohong Liu, Jinqing Wang, and Shengrong Yang
ACS Applied Materials & Interfaces 2013 Volume 5(Issue 16) pp:8044
Publication Date(Web):August 2, 2013
DOI:10.1021/am402127u
This study reports a simple synthesis of amorphous nickel tungstate (NiWO4) nanostructure and its application as a novel cathode material for supercapacitors. The effect of reaction temperature on the electrochemical properties of the NiWO4 electrode was studied, and results demonstrate that the material synthesized at 70 °C (NiW-70) has shown the highest specific capacitance of 586.2 F g–1 at 0.5 A g–1 in a three-electrode system. To achieve a high energy density, a NiW-70//activated carbon asymmetric supercapacitor is successfully assembled by use of NiW-70 and activated carbon as the cathode and anode, respectively, and then, its electrochemical performance is characterized by cyclic voltammetry and galvanostatic charge–discharge measurements. The results show that the assembled asymmetric supercapacitor can be cycled reversibly between 0 and 1.6 V with a high specific capacitance of 71.1 F g–1 at 0.25 A g–1, which can deliver a maximum energy density of 25.3 Wh kg–1 at a power density of 200 W kg–1. Furthermore, this asymmetric supercapacitor also presented an excellent, long cycle life along with 91.4% specific capacitance being retained after 5000 consecutive times of cycling.Keywords: asymmetric supercapacitor; electrode materials; energy storage; nickel tungstate;
Co-reporter:Lengyuan Niu, Zhangpeng Li, Wei Hong, Jinfeng Sun, Zhaofeng Wang, Limin Ma, Jinqing Wang, Shengrong Yang
Electrochimica Acta 2013 Volume 108() pp:666-673
Publication Date(Web):1 October 2013
DOI:10.1016/j.electacta.2013.07.025
•Boron-doped graphene was prepared by pyrolysis of graphene oxide with boric acid at 900 °C under an argon atmosphere.•The boron doping content reached the highest value of 4.7% after 3 h of pyrolysis at 900 °C.•The BG-900-3h electrode exhibited the highest specific capacitance of 172.5 F g−1 at 0.5 A g−1 and maintained 96.5% of initial capacity after a continuous of 5000 times cycling.Chemical doping with foreign atoms is an effective approach to intrinsically modify the properties of the carbon materials. Herein, boron-doped graphene (BG) was prepared through pyrolysis of graphene oxide (GO) with boric acid (H3BO3) in an argon atmosphere at 900 °C. Both boron-doping and reduction of GO to graphene were simultaneously achieved under the thermal treatment processing. Namely, at high temperature condition, H3BO3 was converted into boron oxide (B2O3) accompanied by diffusing B2O3 vapor into the graphene nanosheets, then boron atoms can replace the carbon atoms inside the graphene layers and thereby substitutionally doped into the graphene lattice. The boron content in BG increased with prolonging the reaction time and reached the highest value of 4.7% after 3 h of pyrolysis, which in turn affected their electrochemical properties. The as-prepared electrode of BG-900-3h exhibits the highest capacitive behavior (172.5 F g−1, 0.5 A g−1) and superior cycling stability (maintaining 96.5% of initial capacity after 5000 times of cycling). Remarkably, the boron-doping increased the capacitance of BG-900-3h by about 80% compared to pristine graphene. These results imply that the doping of boron into graphene lattice induces remarkable performance enhancement, and thus make the doped materials superior to those of pristine graphene as electrode materials for supercapacitors.
Co-reporter:Zengjie Fan, Bin Liu, Xiaohong Liu, Zhangpeng Li, Honggang Wang, Shengrong Yang, Jinqing Wang
Electrochimica Acta 2013 Volume 109() pp:602-608
Publication Date(Web):30 October 2013
DOI:10.1016/j.electacta.2013.07.153
A non-enzymatic glucose sensor based on Cu nanowires (CuNWs) modified graphene transparent electrode (GTE) was developed as a substitute for indium tin oxide (ITO) electrode or glassy carbon electrode (GCE). GTE was prepared by four steps on the polyethylene terephthalate sheet, and then Cu nanowires were deposited onto GTE to achieve the hybrid electrode of CuNWs/GTE by spin-coating. The morphology and phase structures were characterized by scanning electron microscopy and X-ray power diffraction, respectively. The resistance and electrochemical properties of CuNWs/GTE were investigated by four point probe and cyclic voltammetry, respectively. Results indicated that the as-prepared sensor showed higher electrocatalytic activity toward glucose than pristine CuNWs and GTE; The sensor also showed wider linear response for glucose over concentrations ranging from 0.005 to 6.0 mM with a sensitivity of 1100 μA/(mM cm2), low detection limit of 1.6 μM (S/N = 3), and excellent anti-interference ability. More importantly, the as-prepared sensor had the similar or even better performances compared to those reported on ITO and GCE.
Co-reporter:Jinfeng Sun, Zhangpeng Li, Jinqing Wang, Zhaofeng Wang, Lengyuan Niu, Peiwei Gong, Xiaohong Liu, Honggang Wang, Shengrong Yang
Journal of Alloys and Compounds 2013 Volume 581() pp:217-222
Publication Date(Web):25 December 2013
DOI:10.1016/j.jallcom.2013.07.023
•Ni(HCO3)2/GS composites were prepared by a simple solvothermal method.•Ni(HCO3)2/GS composites exhibited good supercapacitive performance.•Ni(HCO3)2/GS2 presented the highest capacitance of 1200 F g−1 at 4 A g−1.In this work, a series of composites consisting of Ni(HCO3)2 and graphene nanosheets (GS) have been prepared by a facile solvothermal method, and then their application as electrode materials for supercapacitors has been investigated by cyclic voltammetry (CV) and galvanostatic charge–discharge tests. Morphological and structural analyses by field-emission scanning electron microscopy, high resolution transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy indicated that Ni(HCO3)2 particles deposited on the GS and formed a loosely packed microstructure, actualizing the successful combination of Ni(HCO3)2 particles with GS. Among the prepared composites, the sample of Ni(HCO3)2/GS2 exhibited the highest capacitance of 1200 F g−1 at a current density of 4 A g−1, illustrating that such composite is a promising candidate as electrode material for supercapacitors. Moreover, the Faradic redox mechanism of the Ni(HCO3)2/GS composite was further studied in virtue of XRD analysis, which revealed that the Ni(HCO3)2 phase could be quickly transformed into Ni(OH)2 phase by an electrochemically induced phase transformation process during the galvanostatic charge–discharge tests.
Co-reporter:Lengyuan Niu, Zhangpeng Li, Jinfeng Sun, Zengjie Fan, Ye Xu, Peiwei Gong, Shengrong Yang, Jinqing Wang
Journal of Alloys and Compounds 2013 Volume 575() pp:152-157
Publication Date(Web):25 October 2013
DOI:10.1016/j.jallcom.2013.04.010
•Ni@C core–shell composites were prepared by a simple hydrothermal method.•Ni@C composites exhibit good electrochemical performance for supercapacitors.•The composite displays the highest specific capacitance of 530 F g−1 at 1 A g−1.•An uniform carbon layer is very important for achieving a high electrochemical performance.Ni@C core–shell composites with different crystal structures were synthesized by chemical reduction of nickel (II) acetate tetrahydrate using ethylene glycol as reducing agent and sodium citrate as a carbon source, followed by annealing at different temperatures in the nitrogen atmosphere. X-ray diffraction analysis indicates that the crystal structure of Ni is dependent on the annealing temperatures. At 250 °C, both face-centered cubic and hexagonal closed-packed (hcp) phases of Ni coexist in the Ni@C composites, whereas there is only hcp phase Ni observed as being annealed at 300 °C. The synthesized Ni@C composites were applied as electrode materials for supercapacitors and exhibited superior electrochemical performances. Especially, the electrode annealed at 250 °C displays the highest specific capacitance of 530 F g−1 in 2 M KOH solution at a current density of 1 A g−1. In addition, the synthesized Ni@C composite electrodes also show excellent rate capability and cycle stability, presenting the promising potential as electrode material for supercapacitors.
Co-reporter:Zengjie Fan, Jinqing Wang, Zhaofeng Wang, Zhangpeng Li, Yinong Qiu, Honggang Wang, Ye Xu, Lengyuan Niu, Peiwei Gong, and Shengrong Yang
The Journal of Physical Chemistry C 2013 Volume 117(Issue 20) pp:10375-10382
Publication Date(Web):April 29, 2013
DOI:10.1021/jp312163m
Casein phosphopeptides (CPPs) with abundant phosphoserine clusters can mediate hydroxyapatite (HA) nucleation and growth. In this work, a new type of CPPs-biofuctionalized graphene composite was synthesized by amidation reaction between CPPs and carboxyalated graphene (CGO). When immersed in stimulated body fluid (1.5 × SBF) at 37 °C for different periods, the CPPs layer on the composite facilitated efficient interaction between the CGO surface and mineral ions, which promoted HA nanoparticle formation and shortened mineralization time in comparison with pristine CGO. The synthesis of the composite mimicked the natural biomineralization of bone, demonstrating that CPPs can effectively improve the bioactivity of graphene and be useful for HA formation. The presented biocomposite may have potential biomedical applications in different areas.
Co-reporter:Yongjuan Mi, Zhaofeng Wang, Xiaohong Liu, Shengrong Yang, Honggang Wang, Junfei Ou, Zhangpeng Li and Jinqing Wang
Journal of Materials Chemistry A 2012 vol. 22(Issue 16) pp:8036-8042
Publication Date(Web):15 Mar 2012
DOI:10.1039/C2JM16656A
In this work, we present a simple and feasible method with broad applicability for the in-situ reduction and assembly of graphene lubricant films on various substrates. We adopt graphene oxide hydrosol as the precursor solution and creatively introduce an adherent coating of polydopamine that can be firmly bonded onto a wide range of substrates and acts as an active transition layer and in-situ reducing agent, aiming at obtaining the reduced graphene oxide (rGO) films thereon without addition of exogenous reducing agent. Experimental results prove that rGO nanosheets have been successfully assembled onto the substrates and the in-situ synthesized rGO film presents excellent morphology, outstanding friction reduction and wear resistance properties.
Co-reporter:Peiwei Gong, Zhaofeng Wang, Jinqing Wang, Honggang Wang, Zhangpeng Li, Zengjie Fan, Ye Xu, Xiuxun Han and Shengrong Yang
Journal of Materials Chemistry A 2012 vol. 22(Issue 33) pp:16950-16956
Publication Date(Web):28 Jun 2012
DOI:10.1039/C2JM32294C
Fluorographene (FG), which inherits the properties of graphene and fluorographite (FGi), holds great promise for applications in high-performance materials and devices, including lubricants, nanocomposites, batteries, and nanoelectronics. However, challenges for realizing large-scale preparation and little knowledge concerning FG's physicochemical properties hinder its practical applications. Here, a novel and feasible method is developed to prepare FG through a simple sonochemical exfoliation process in N-methyl-2-pyrrolidone (NMP). Interestingly, FG at a high concentration in NMP displays dramatic stability without any additional stabilizer or modifier, and the C/F ratio of FG can be facilely tuned just by adjusting the sonochemical time. Furthermore, the electrochemical and thermal properties of the prepared FG have been systematically investigated and exhibited regularity with variation of fluorine coverage. On the other hand, based on the solubility of FG in various solvents, a possible dispersion mechanism is proposed to guide FG's further applications in films or polymer-based composites as a mechanical reinforcement.
Co-reporter:Sheng Liu, Junfei Ou, Zhangpeng Li, Shengrong Yang, Jinqing Wang
Applied Surface Science 2012 Volume 258(Issue 7) pp:2231-2236
Publication Date(Web):15 January 2012
DOI:10.1016/j.apsusc.2011.09.011
Abstract
A series of graphene sheets (GS)-based multilayer films was constructed in virtue of layer-by-layer electrostatic self-assembly technique based on the negatively charged poly(sodium 4-styrenesulfonate) (PSS) mediated GS (PSS-GS) and the positively charged polyethyleneimine (PEI). High-resolution transmission electron microscope, atomic force microscope and micro-Raman spectrum characterizations demonstrated that the PSS-GS has been synthesized and could be assembled on the single-crystal silicon substrate. Ellipsometric thickness measurement and ultraviolet–visible absorption spectroscope confirmed the successive assemblies of GS. Finally, the macrotribological behaviors of different multilayer films were evaluated on a ball-on-plate macrotribometer and the results indicated that the prepared three- and five-layer films had high load affording ability and long anti-wear life, which could be highly dependent upon the high coverage and excellent self-lubricant properties that the GS owns intrinsically.
Co-reporter:Zhaofeng Wang, Jinqing Wang, Zhangpeng Li, Peiwei Gong, Junfang Ren, Honggang Wang, Xiuxun Han and Shengrong Yang
RSC Advances 2012 vol. 2(Issue 31) pp:11681-11686
Publication Date(Web):25 Sep 2012
DOI:10.1039/C2RA21871B
We report a novel and effective method to prepare fluorinated graphene sheets (FGS) by the cooperative exfoliation of graphite fluoride using cetyl-trimethyl-ammonium bromide and dopamine. This facile, scalable preparation route results in wide (about 2 μm in width), long (at least 3 μm in length) and ultrathin (1–2 layers) FGS with uniform morphology. The chemical composition of FGS was characterized by X-ray photoelectron spectroscopy and energy dispersive X-ray spectroscopy. The obtained FGS exhibits full-color emission when excited by near ultraviolet (NUV) rays, suggesting its potential applications in luminescence devices, such as NUV-pumped FGS-based flexible light-emitting diodes.
Co-reporter:Zhangpeng Li, Jinqing Wang, Zhaofeng Wang, Haiqiong Ran, Yang Li, Xiuxun Han and Shengrong Yang
New Journal of Chemistry 2012 vol. 36(Issue 7) pp:1490-1495
Publication Date(Web):10 May 2012
DOI:10.1039/C2NJ21052E
In this work, a facile hydrothermal method has been developed to synthesize a three-dimensional porous birnessite manganese dioxide hierarchical structure (pMHs) using thermally reduced graphene oxide paper as a sacrificing template. The morphology, microstructure, and thermal stability of the obtained samples were characterized by field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy, N2 adsorption–desorption isotherms, and thermal gravimetric analysis. Furthermore, the electrochemical properties of the pMHs as an electrode material for supercapacitor were investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy in 1 M Na2SO4 electrolyte, and a specific capacitance of 194 F g−1 was achieved at a current density of 0.1 A g−1. The long-term stability implies that the synthesized pMHs is a good candidate as an electrode material for SCs.
Co-reporter:Sheng Liu, Hongmin Xu, Junfei Ou, Zhangpeng Li, Shengrong Yang, Jinqing Wang
Materials Chemistry and Physics 2012 Volume 132(2–3) pp:500-504
Publication Date(Web):15 February 2012
DOI:10.1016/j.matchemphys.2011.11.060
In this work, one dimensional gold/polyaniline (Au/PANi) nanofiber composites are successfully synthesized via electrostatic adsorption and in situ reduction of HAuCl4. By observations of field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM), it is clearly seen that the as-prepared Au nanoparticles were uniformly distributed on the PANi surface. In addition, the synthesized Au/PANi nanofiber composites are also characterized by X-ray diffraction (XRD) analysis, Raman, Fourier transform infrared (FTIR), and UV–vis absorption spectra, and the results further confirm Au/PANi nanofiber composites have been synthesized and the strong interaction between PANi and Au nanoparticles indeed exists. Thermogravimetry (TG) analysis indicates that the thermal stability of the nanocomposites of Au/PANi is improved compared to the pure PANi. More importantly, the nanocomposites of Au/PANi show good electrocatalytic behavior toward oxygen reduction.Graphical abstractHighlights► Gold/polyaniline (Au/PANi) nanofiber composites are synthesized via electrostatic adsorption and in situ reduction. ► The as-prepared Au nanoparticles are uniformly distributed on the PANi nanofiber surfaces. ► Au/PANi nanocomposites show good electrocatalytic behavior toward oxygen reduction.
Co-reporter:Zhaofeng Wang, Jinqing Wang, Zhangpeng Li, Peiwei Gong, Xiaohong Liu, Libin Zhang, Junfang Ren, Honggang Wang, Shengrong Yang
Carbon 2012 50(15) pp: 5403-5410
Publication Date(Web):
DOI:10.1016/j.carbon.2012.07.026
Co-reporter:Li-Bin Zhang, Jin-Qing Wang, Hong-Gang Wang, Ye Xu, Zhao-Feng Wang, Zhang-Peng Li, Yong-Juan Mi, Sheng-Rong Yang
Composites Part A: Applied Science and Manufacturing 2012 Volume 43(Issue 9) pp:1537-1545
Publication Date(Web):September 2012
DOI:10.1016/j.compositesa.2012.03.026
Graphene oxide sheets with isocyanate functional groups (GONCO) were firstly synthesized and functionalized graphene/polyimide (FGS/PI) nanocomposites were subsequently prepared by typical solution casting and thermal imidization. The chemical changes of GONCO during the preparation of FGS/PI nanocomposites were carefully characterized by Fourier transfer infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses. As a result, the morphology analysis indicated that the FGS were dispersed in the PI matrix and were aligned more orderly with increasing the FGS contents. The tensile strength and the modulus of FGS/PI nanocomposites were significantly increased by 60% with a small quantity of 0.75 wt% FGS incorporated and decreased beyond that dosage. Moreover, the thermogravimetric analysis (TGA) results revealed that the thermal stability of PI was slightly improved by the incorporation of FGS.
Co-reporter:Zhangpeng Li, Yongjuan Mi, Xiaohong Liu, Sheng Liu, Shengrong Yang and Jinqing Wang
Journal of Materials Chemistry A 2011 vol. 21(Issue 38) pp:14706-14711
Publication Date(Web):15 Aug 2011
DOI:10.1039/C1JM11941A
Graphene/manganese dioxide (MnO2) composite papers (GMCP) are fabricated via a simple three-step route: preparation of graphene oxide/MnO2 composite (GOMC) dispersion, subsequent vacuum filtration of GOMC dispersion to achieve graphene oxide/MnO2 composite paper (GOMCP), and finally thermal reduction of GOMCP to generate GMCP. The morphology and microstructure of the prepared samples are characterized by field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, Fourier transformation infrared spectroscopy, thermal gravimetric analysis and X-ray photoelectron spectroscopy. Moreover, as a binder-free and flexible electrode material for supercapacitors, the electrochemical properties of the prepared GMCP are evaluated by cyclic voltammetry and galvanostatic charge/discharge tests. As a result, the specific capacitance of the GMCP with the MnO2 weight ratio of 24% (GMCP-24) reaches 256 F g−1 at a current density of 500 mA g−1 and also shows good cycle stability, indicating a promising potential application as an effective electrode material for supercapacitors.
Co-reporter:Zhangpeng Li, Jinqing Wang, Xiaohong Liu, Sheng Liu, Junfei Ou and Shengrong Yang
Journal of Materials Chemistry A 2011 vol. 21(Issue 10) pp:3397-3403
Publication Date(Web):31 Jan 2011
DOI:10.1039/C0JM02650F
A new class of multilayer films was constructed by electrostatic layer-by-layer self-assembly, using poly(sodium 4-styrenesulfonate) mediated graphene sheets (PSS-GS), manganese dioxide (MnO2) sheets, and poly(diallyldimethylammonium) (PDDA) as building blocks. UV-vis spectroscopy, field-emission scanning electron microscopy and X-ray photoelectron spectroscopy were used to characterize the microstructures and morphologies of the multilayer films. Capacitive properties of the synthesized multilayer film electrodes were studied using cyclic voltammetry and galvanostatic charge/discharge in 0.1 M Na2SO4 electrolyte. The specific capacitance of the ITO/(PDDA/PSS-GS/PDDA/MnO2)10electrode reached 263 F g−1 at a discharge current density of 0.283 A g−1; moreover, this film electrode also shows a good cyclic stability and high Coulombic efficiency. Anticipatedly, the synthesized multilayer films will find promising applications as a novel electrode material in supercapacitors and other devices in virtue of their outstanding characteristics of controllable capacitance, good cycle stability, low cost and environmentally benign nature.
Co-reporter:Zhangpeng Li, Jinqing Wang, Sheng Liu, Xiaohong Liu, Shengrong Yang
Journal of Power Sources 2011 Volume 196(Issue 19) pp:8160-8165
Publication Date(Web):1 October 2011
DOI:10.1016/j.jpowsour.2011.05.036
Hydrothermally reduced graphene/MnO2 (HRG/MnO2) composites were synthesized by dipping HRG into the mixed aqueous solution of 0.1 M KMnO4 and 0.1 M K2SO4 for different periods of time at room temperature. The morphology and microstructure of the as-prepared composites were characterized by field-emission scanning electron microscopy, X-ray diffraction, Raman microscope, and X-ray photoelectron spectroscopy. The characterizations indicate that MnO2 successfully deposited on HRG surfaces and the morphology of the HRG/MnO2 shows a three-dimensional porous structure with MnO2 homogenously distributing on the HRG surfaces. Capacitive properties of the synthesized composite electrodes were studied using cyclic voltammetry and electrochemical impedance spectroscopy in a three-electrode experimental setup using 1 M Na2SO4 aqueous solution as electrolyte. The main results of electrochemical tests are drawn as follows: the specific capacitance value of HRG/MnO2–200 (HRG dipped into the mixed solution of 0.1 M KMnO4 and 0.1 M K2SO4 for 200 min) electrode reached 211.5 F g−1 at a potential scan rate of 2 mV s−1; moreover, this electrode shows a good cyclic stability and capacity retention. It is anticipated that the synthesized HRG/MnO2 composites will find promising applications in supercapacitors and other devices in virtue of their outstanding characters of good cycle stability, low cost and environmentally benign nature.
Co-reporter:Penghua Yan, Jinqing Wang, Lin Wang, Bin Liu, Ziqiang Lei, Shengrong Yang
Applied Surface Science 2011 Volume 257(Issue 11) pp:4849-4855
Publication Date(Web):15 March 2011
DOI:10.1016/j.apsusc.2010.12.111
Abstract
In this work, polydopamine coated carbon nanotubes were firstly prepared by a simple and feasible route. Then, for comparison, the in vitro bioactivity and cytocompatibility of the carbon nanotubes and the polydopamine coated carbon nanotubes were assessed by immersion study in simulated body fluids and 3-(4,5-dimethyldiazol-2-yl)-2,5-diphenyl tetrazolium bromide test using osteoblast cells (MC3T3-E1), respectively. As a result, it has been demonstrated that the introduction of polydopamine coating can greatly enhance the bioactivity and promote cell proliferation of the carbon nanotubes. The improvement of bioactive behavior is attributed to the good combination of catecholamines structure of the polydopamine and the structural advantages of carbon nanotubes as a framework material. It is anticipated that the polydopamine coated carbon nanotubes would find potential applications in bone tissue engineering and other biomedical areas.
Co-reporter:Sheng Liu, Xiaohong Liu, Zhangpeng Li, Shengrong Yang and Jinqing Wang
New Journal of Chemistry 2011 vol. 35(Issue 2) pp:369-374
Publication Date(Web):10 Dec 2010
DOI:10.1039/C0NJ00718H
Flexible graphene sheet (GS)/polyaniline (PANi) nanofibers composite paper was prepared via a facile and fast two-step route composed of electrostatic adsorption between negatively-charged poly(sodium 4-styrenesulfonate) (PSS) mediated GS (coded as PSS-GS) and positively-charged PANi nanofibers and the follow-up vacuum filtration of the as-prepared PSS-GS/PANi nanofibers suspension. By observations of field emission scanning electron microscopy (FE-SEM) and high resolution transmission electron microscopy (HR-TEM), it is clearly seen that representative and highly ordered layered PSS-GS/PANi composite papers have been achieved and PANi nanofibers are coated by PSS-GS. In addition, the synthesized PSS-GS/PANi composite papers are also characterized by Raman spectroscopy and Fourier transform infrared (FTIR) spectroscopy, and the results further confirm the successful synthesis of PSS-GS/PANi composites and the existence of strong interaction between PSS-GS and PANi nanofibers. The most interesting thing is the effective synergy can remarkably improve electrochemical properties of GS by introducing PANi nanofibers, which can ascribe to high surface area of GS and good combination between PSS-GS and PANi nanofibers. The highest specific capacitance of the composites reaches 301 F/g. Thermogravimetry analysis (TGA) indicates that the thermal stability of the PSS-GS/PANi composites is obviously improved compared to the pure PSS-GS and PANi.
Co-reporter:Junfei Ou ; Ying Wang ; Jinqing Wang ; Sheng Liu ; Zhangpeng Li ;Shengrong Yang
The Journal of Physical Chemistry C 2011 Volume 115(Issue 20) pp:10080-10086
Publication Date(Web):May 4, 2011
DOI:10.1021/jp200597k
Taking advantage of the condensation between Si–OH of the hydroxylated octadecyltrichlorosilane (OTS) and C–OH on graphene oxide (GO) surface, we grafted OTS onto the GO-based dual-layer film, which was composed of GO outerlayer and (3-aminopropyl)triethoxysilane (APTES) self-assembled underlayer, on a Si substrate. Thus, a hydrophobic trilayer film coded as APTES-GO-OTS was prepared successfully. To confirm the chemical composition, structure, and morphology of the trilayer film, various means including water contact angle measurement, attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectrometry, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM) were performed. Moreover, to investigate the tribological performances, the micro- and macrotribological experiments were conducted with AFM and a UMT tribometer. The results showed that the as-prepared trilayer film exhibited low adhesion and greatly reduced the friction force in both the micro- and macroscale. Therefore, such a trilayer film is suitable for an application in the lubrication and protection of nano/microelectromechanical systems (NEMS/MEMS).
Co-reporter:Sheng Liu;Junfei Ou;Jinqing Wang;Xiaohong Liu
Journal of Applied Electrochemistry 2011 Volume 41( Issue 7) pp:
Publication Date(Web):2011 July
DOI:10.1007/s10800-011-0304-1
In this study, a simple and controllable two-step electrochemical process is described for the synthesis of graphene sheets (GS) film on a cleaned indium tin oxide (ITO) sheet electrode. Namely, the main procedures involve the electrophoretic deposition (EPD) of graphene oxide (GO) film onto ITO electrode and the subsequent in situ electrochemical reduction (ECR) of GO to generate GS film. X-ray photoelectron spectroscopy (XPS) measurement demonstrates that most of the oxygen-containing functional groups in GO film have been removed after ECR. By electrochemical measurements, the maximum specific capacitance of the prepared GS film electrode was calculated to be 156 F g−1, besides, the capacitance retention of the material remained 78% after 400 times of cycling, showing a promising prospect as supercapacitor materials.
Co-reporter:Sheng Liu, Jinqing Wang, Jing Zeng, Junfei Ou, Zhangpeng Li, Xiaohong Liu, Shengrong Yang
Journal of Power Sources 2010 Volume 195(Issue 15) pp:4628-4633
Publication Date(Web):1 August 2010
DOI:10.1016/j.jpowsour.2010.02.024
Nanocomposite films of platinum nanoparticle-deposited expandable graphene sheet (Pt/EGS) are fabricated on conductive indium tin oxide glass electrodes via a “green” electrochemical synthetic route involving a series of electrochemical processes. The microstructure and morphology of the prepared film samples are characterized by Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, three-dimensional non-contact surface mapping, and field emission scanning electron microscopy. At the same time, the catalytic activity and stability of the Pt/EGS film for the oxidation of methanol are evaluated through cyclic voltammetry and chronoamperometry tests. The Pt nanoparticles in the Pt/EGS nanocomposite film are found to be uniformly distributed on the EGS. The as-synthesized Pt/EGS nanocomposite exhibits high catalytic activity and good stability for the oxidation of methanol, which may be attributed to its excellent electrical conductivity and the high specific surface area of the graphene sheet catalyst support.
Co-reporter:Penghua Yan, Jinqing Wang, Junfei Ou, Zhangpeng Li, Ziqiang Lei, Shengrong Yang
Materials Letters 2010 Volume 64(Issue 22) pp:2544-2547
Publication Date(Web):30 November 2010
DOI:10.1016/j.matlet.2010.08.033
Three-dimensional ordered mesoporous–macroporous bioactive glass (MMBG) was synthesized by a combination of surfactant and polystyrene bead templates, the sol–gel method, and the evaporation-induced self-assembly process. The incorporation of regular spherical macropores only slightly perturbed the mesoporous network. The bioactivity of the MMBG was assessed by its immersion in simulated body fluid for different lengths of time and the subsequent determination of hydroxycarbonate apatite formation. The synthesized MMBG displayed good in vitro bioactivity and may have potential applications in bone tissue engineering.
Co-reporter:Junfei Ou, Jinqing Wang, Sheng Liu, Bo Mu, Junfang Ren, Honggang Wang, and Shengrong Yang
Langmuir 2010 Volume 26(Issue 20) pp:15830-15836
Publication Date(Web):September 28, 2010
DOI:10.1021/la102862d
Reduced graphene oxide (RGO) sheets were covalently assembled onto silicon wafers via a multistep route based on the chemical adsorption and thermal reduction of graphene oxide (GO). The formation and microstructure of RGO were analyzed by X-ray photoelectron spectroscopy (XPS), attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Raman spectroscopy, and water contact angle (WCA) measurements. Characterization by atomic force microscopy (AFM) was performed to evaluate the morphology and microtribological behaviors of the samples. Macrotribological performance was tested on a ball-on-plate tribometer. Results show that the assembled RGO possesses good friction reduction and antiwear ability, properties ascribed to its intrinsic structure, that is, the covalent bonding to the substrate and self-lubricating property of RGO.
Co-reporter:Kaiming Hou, Jinqing Wang, Zhigang Yang, Limin Ma, Zhaofeng Wang, Shengrong Yang
Carbon (May 2017) Volume 115() pp:83-94
Publication Date(Web):May 2017
DOI:10.1016/j.carbon.2016.12.089
Co-reporter:Hong Yuan, Xiaohong Liu, Limin Ma, Zhigang Yang, Honggang Wang, Jinqing Wang, Shengrong Yang
Composites Part A: Applied Science and Manufacturing (April 2017) Volume 95() pp:220-228
Publication Date(Web):April 2017
DOI:10.1016/j.compositesa.2017.01.018
Co-reporter:Zhangpeng Li, Jinqing Wang, Xiaohong Liu, Sheng Liu, Junfei Ou and Shengrong Yang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 10) pp:NaN3403-3403
Publication Date(Web):2011/01/31
DOI:10.1039/C0JM02650F
A new class of multilayer films was constructed by electrostatic layer-by-layer self-assembly, using poly(sodium 4-styrenesulfonate) mediated graphene sheets (PSS-GS), manganese dioxide (MnO2) sheets, and poly(diallyldimethylammonium) (PDDA) as building blocks. UV-vis spectroscopy, field-emission scanning electron microscopy and X-ray photoelectron spectroscopy were used to characterize the microstructures and morphologies of the multilayer films. Capacitive properties of the synthesized multilayer film electrodes were studied using cyclic voltammetry and galvanostatic charge/discharge in 0.1 M Na2SO4 electrolyte. The specific capacitance of the ITO/(PDDA/PSS-GS/PDDA/MnO2)10electrode reached 263 F g−1 at a discharge current density of 0.283 A g−1; moreover, this film electrode also shows a good cyclic stability and high Coulombic efficiency. Anticipatedly, the synthesized multilayer films will find promising applications as a novel electrode material in supercapacitors and other devices in virtue of their outstanding characteristics of controllable capacitance, good cycle stability, low cost and environmentally benign nature.
Co-reporter:Peiwei Gong, Zhaofeng Wang, Jinqing Wang, Honggang Wang, Zhangpeng Li, Zengjie Fan, Ye Xu, Xiuxun Han and Shengrong Yang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 33) pp:NaN16956-16956
Publication Date(Web):2012/06/28
DOI:10.1039/C2JM32294C
Fluorographene (FG), which inherits the properties of graphene and fluorographite (FGi), holds great promise for applications in high-performance materials and devices, including lubricants, nanocomposites, batteries, and nanoelectronics. However, challenges for realizing large-scale preparation and little knowledge concerning FG's physicochemical properties hinder its practical applications. Here, a novel and feasible method is developed to prepare FG through a simple sonochemical exfoliation process in N-methyl-2-pyrrolidone (NMP). Interestingly, FG at a high concentration in NMP displays dramatic stability without any additional stabilizer or modifier, and the C/F ratio of FG can be facilely tuned just by adjusting the sonochemical time. Furthermore, the electrochemical and thermal properties of the prepared FG have been systematically investigated and exhibited regularity with variation of fluorine coverage. On the other hand, based on the solubility of FG in various solvents, a possible dispersion mechanism is proposed to guide FG's further applications in films or polymer-based composites as a mechanical reinforcement.
Co-reporter:Yongjuan Mi, Zhaofeng Wang, Xiaohong Liu, Shengrong Yang, Honggang Wang, Junfei Ou, Zhangpeng Li and Jinqing Wang
Journal of Materials Chemistry A 2012 - vol. 22(Issue 16) pp:NaN8042-8042
Publication Date(Web):2012/03/15
DOI:10.1039/C2JM16656A
In this work, we present a simple and feasible method with broad applicability for the in-situ reduction and assembly of graphene lubricant films on various substrates. We adopt graphene oxide hydrosol as the precursor solution and creatively introduce an adherent coating of polydopamine that can be firmly bonded onto a wide range of substrates and acts as an active transition layer and in-situ reducing agent, aiming at obtaining the reduced graphene oxide (rGO) films thereon without addition of exogenous reducing agent. Experimental results prove that rGO nanosheets have been successfully assembled onto the substrates and the in-situ synthesized rGO film presents excellent morphology, outstanding friction reduction and wear resistance properties.
Co-reporter:Ping Wen, Peiwei Gong, Jinfeng Sun, Jinqing Wang and Shengrong Yang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 26) pp:NaN13883-13883
Publication Date(Web):2015/05/22
DOI:10.1039/C5TA02461G
Currently, metal–organic frameworks (MOFs) have been attracting great interest as a new kind of electrode material for energy storage devices, because their porous skeleton would benefit the access and transport of electrolytes, and the exposure of metal ions can offer more active sites to electrolytes. In this study, we have successfully fabricated nickel metal–organic framework/carbon nanotube (Ni-MOF/CNT) composites, which show excellent electrochemical performance due to the synergistic effects of the Ni-MOF specific structure and CNTs with high conductivity, achieving a high specific capacitance of 1765 F g−1 at a current density of 0.5 A g−1. To further explore the capacitive performance of the composite electrode, an asymmetric supercapacitor device using Ni-MOF/CNTs as the positive electrode and reduced graphene oxide/graphitic carbon nitride (rGO/g-C3N4) as the negative electrode was fabricated, and this device could be operated in a working voltage range of 0–1.6 V based on a complementary potential window in 6 M KOH aqueous electrolyte, delivering a high energy density of 36.6 W h kg−1 at a power density of 480 W kg−1. Moreover, this asymmetric supercapacitor revealed an excellent cycle life along with 95% specific capacitance retention after 5000 consecutive charge–discharge tests. These outstanding performances would make MOFs become one of the most promising candidates for the future high energy storage systems.
Co-reporter:Wei Hong, Jinqing Wang, Zhangpeng Li and Shengrong Yang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 6) pp:NaN2540-2540
Publication Date(Web):2014/11/25
DOI:10.1039/C4TA04707A
We have successfully fabricated hybrid Co3O4@Au-decorated PPy core/shell nanowire arrays (NWAs) on Ni foam via in situ interfacial polymerization between HAuCl4 and pyrrole monomers. With the advantages of high electrochemical activity of each component and high electrical conductivity of the Au-decorated PPy layer, this hybrid electrode exhibits remarkable pseudo-capacitive behaviors. This facile synthesis method offers an attractive strategy to further improve the electrochemical performance of pseudo-capacitors, and it undoubtedly shows promising applications in electrochemical energy storage.
Co-reporter:Zhangpeng Li, Yongjuan Mi, Xiaohong Liu, Sheng Liu, Shengrong Yang and Jinqing Wang
Journal of Materials Chemistry A 2011 - vol. 21(Issue 38) pp:NaN14711-14711
Publication Date(Web):2011/08/15
DOI:10.1039/C1JM11941A
Graphene/manganese dioxide (MnO2) composite papers (GMCP) are fabricated via a simple three-step route: preparation of graphene oxide/MnO2 composite (GOMC) dispersion, subsequent vacuum filtration of GOMC dispersion to achieve graphene oxide/MnO2 composite paper (GOMCP), and finally thermal reduction of GOMCP to generate GMCP. The morphology and microstructure of the prepared samples are characterized by field-emission scanning electron microscopy, transmission electron microscopy, Raman spectroscopy, Fourier transformation infrared spectroscopy, thermal gravimetric analysis and X-ray photoelectron spectroscopy. Moreover, as a binder-free and flexible electrode material for supercapacitors, the electrochemical properties of the prepared GMCP are evaluated by cyclic voltammetry and galvanostatic charge/discharge tests. As a result, the specific capacitance of the GMCP with the MnO2 weight ratio of 24% (GMCP-24) reaches 256 F g−1 at a current density of 500 mA g−1 and also shows good cycle stability, indicating a promising potential application as an effective electrode material for supercapacitors.
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![Poly[(5,7-dihydro-1,3,5,7-tetraoxobenzo[1,2-c:4,5-c']dipyrrole-2,6(1H,3H)-diyl)-1,4-phenyleneoxy-1,4-phenylene]](http://img.cochemist.com/ccimg/25100/25036-53-7_b.png)
