Co-reporter:Haiming Sun;Xijia Yang;Lishu Zhang;Lijun Zhao
Journal of Materials Chemistry A 2017 vol. 5(Issue 17) pp:8095-8107
Publication Date(Web):2017/05/03
DOI:10.1039/C7TA00578D
Herein, a novel method was developed to synthesize a CoNi binary metal/Co–Ni oxide@carbon (M/MO@C-600) composite by sintering CoNi nanoparticles with Congo Red (CR) at 600 °C and under a N2 atmosphere; this composite was then utilized to prepare electrode materials. Herein, C and O originated from the CR molecule. The M/MO@C-600 composite with a flaky structure delivered a capacitance of 1134.9 F g−1 at 1 A g−1 and a cycling stability with 66% retention even at the high current density of 10 A g−1 after 2000 cycles. Furthermore, a simple asymmetric supercapacitor (ASC) was developed with the M/MO@C-600 composite as the positive electrode material and commercial activated carbon as the negative electrode material. A high specific capacitance of 111.2 F g−1 (at 0.5 A g−1) and excellent energy density of 44.6 W h kg−1 (at 0.425 kW kg−1) were obtained for the ASC device, and 100% capacitance was retained even after 10 000 cycles at 6 A g−1. This method for the preparation of electrode materials may facilitate to simultaneously relieve the environmental and energy pressure.
Co-reporter:Haiming Sun, Xijia Yang, Lijun Zhao, Tianhao Xu and Jianshe Lian
Journal of Materials Chemistry A 2016 vol. 4(Issue 24) pp:9455-9465
Publication Date(Web):23 May 2016
DOI:10.1039/C6TA02126C
Here we report a flexible one-pot hydrothermal synthesis of an octahedral CoFe/CoFe2O4 submicron composite used as a superior Fenton-like catalyst for the decomposition of organic pollutants in water. As a peroxymonosulfate (PMS) catalyst, the non-toxic CoFe/CoFe2O4 submicron composite can highly efficiently decompose Orange II (30 mg L−1, 1.5 min and 60 mg L−1, 3 min). Especially, the CoFe/CoFe2O4 submicron composite exhibits better generalization for the degradation of different organic pollutants and excellent reusability due to its large size and structural stability. Furthermore, its high saturation magnetization (123.7 emu g−1) makes it convenient to magnetically separate from aqueous phase after catalysing the reaction, and its relatively large size is conducive to solving or minimizing secondary pollution. Meanwhile, the probable mechanism of PMS activation with CoFe/CoFe2O4 catalyst is proposed.
Co-reporter:Xiaobing Wang, Jin Hao, Yichang Su, Fanggang Liu, Jian An and Jianshe Lian
Journal of Materials Chemistry A 2016 vol. 4(Issue 33) pp:12929-12939
Publication Date(Web):23 Jul 2016
DOI:10.1039/C6TA04022E
Multi-layer NixZn1−xS/Ni foam composites were synthesized by the facile method of a one-step hydrothermal reaction on a frame of Ni foam. The Zn element plays a critical role in constructing the multi-layer nanostructure. In particular, various layers with different morphologies work with good synergistic effect to provide an excellent electrochemical performance. The as-synthesized Ni1−xZnxS/Ni foam-2 h electrode shows a high specific capacitance (1815 F g−1 at 1 A g−1) and outstanding rate properties (1050 F g−1 at 100 A g−1 and 50.1% rate retention over 200 A g−1). Moreover, a two-electrode Ni1−xZnxS/Ni foam-2 h//active carbon–graphene (AC–G) asymmetric supercapacitor device was fabricated and it delivers both a high specific energy density and an excellent cycling stability. The strategy presented here for constructing multi-layer structures is facile and effective, and could be expanded as a general method.
Co-reporter:Haiming Sun, Xijia Yang, Lijun Zhao, Yue Li, Jiamu Zhang, Lu Tang, Yining Zou, Cong Dong, Jianshe Lian and Qing Jiang
RSC Advances 2016 vol. 6(Issue 11) pp:9209-9220
Publication Date(Web):14 Jan 2016
DOI:10.1039/C5RA24886H
Use change of composition and surface defects of CoxNi1−x bimetallic alloy prepared at room temperature to improve their adsorption capabilities. Congo red (CR) was used to evaluate the CoxNi1−x bimetallic alloys' adsorption capabilities. At 100 mg L−1 of initial CR concentration, 1000 mg g−1 of adsorption capacity could be achieved by the CoxNi1−x nanoparticles in time range of 2 to 20 minutes. Here, Co0.6Ni0.4 bimetallic alloy shows the best adsorption efficiency, reaching 1000 mg g−1 at 2 min. Furthermore, density functional theory (DFT) simulations were introduced to understand why Co0.6Ni0.4 bimetallic alloy had better adsorption efficiency than monometal Co and Ni. Based on DFT simulations, large surface energy, low work function and high reducibility of Co0.6Ni0.4 bimetallic alloy may be responsible for its high adsorption capability and efficiency. By a further investigation on surface electronic structure, it can be found that the chemical composition and surface defects have influences on d-band center, and a proper d-band center may facilitate to both the high rate of electrons transfer to adsorbate and removal of surface intermediate. The combination of experiment and DFT simulations proved that the adsorption ability of Co0.6Ni0.4 bimetallic alloy is better than that of single metal, and shows promise as commercial scale magnetic adsorbent.
Co-reporter:Xiaobing Wang, Jiangjiang Hu, Weidong Liu, Guoyong Wang, Jian An and Jianshe Lian
Journal of Materials Chemistry A 2015 vol. 3(Issue 46) pp:23333-23344
Publication Date(Web):06 Oct 2015
DOI:10.1039/C5TA07169K
To avoid aggregation in the production of the active electrode material, Ni–Zn system materials (NixZn1−xOH, NiO–ZnO and NixZn1−xS) were synthesized by using a belt reaction zone model, and then were characterized systematically in this work. Among these materials, NixZn1−xS porous spheroid nanoparticles with diameters ∼30 nm possess abundant interconnected micropores caused by the Kirkendall effect in the synthesis, leading to a high surface area of 148.4 m2 g−1 and special paths for ion diffusion. In the three-electrode system testing, NixZn1−xS porous spheroid nanoparticles show the highest specific capacitance of 1867 F g−1 at a current density of 1 A g−1, as well as excellent rate capability and cycling stability. Using NixZn1−xS as the positive electrode and active carbon as the negative electrode, the asymmetric supercapacitor device exhibits an excellent electrochemical performance. The results provide us with a modified method to synthesize metal hydroxides, oxides and sulfides, in order to obtain materials with high supercapacitor performance.
Co-reporter:Shanshan Xiao, Yingqi Li, Jiangjiang Hu, Heng Li, Xingpu Zhang, Li Liu and Jianshe Lian
CrystEngComm 2015 vol. 17(Issue 20) pp:3809-3819
Publication Date(Web):10 Apr 2015
DOI:10.1039/C5CE00338E
Nanostructured Bi–Bi2O2CO3–ZnO composites were successfully prepared through a facile one-step hydrothermal method. The composite was constructed by ZnO nanorods with a diameter of 30–40 nm embedded in Bi2O2CO3 platelets with a small quantity of Bi particles dispersed on the platelets, which further assembled into micron clusters. The photocatalytic performance of the composite was evaluated by the degradation of methyl orange and phenol under UV and visible light irradiation, respectively. The results revealed that the composites showed enhanced photocatalytic activity in comparison with either ZnO or Bi2O2CO3, and the Bi–Bi2O2CO3–ZnO photocatalyst with 20 mol% of Bi2O2CO3 exhibited the best photocatalytic efficiency. The reusability test explored the reliable stability and reusability for industrial applications, which was endowed by the special feature of nanostructured micron clusters. The superior photocatalytic activity could be attributed to the heterojunction interfaces and compound band gap structure which facilitated the separation of the photo-generated electrons and holes at the interface and promoted an effective charge transfer path. Additionally, the existing metal Bi also acted as electron traps to manifest a positive effect. The present study might give an insight into the design of novel heterostructured materials for the light harvesting related environment management and energy conversion applications.
Co-reporter:Weidong Liu, Xiaobing Wang, Lishu Zhang and Jianshe Lian
RSC Advances 2015 vol. 5(Issue 67) pp:54138-54147
Publication Date(Web):11 Jun 2015
DOI:10.1039/C5RA06022B
We demonstrate a facile one-step interface approach to in situ grow MnO–NiO nanoparticles on reduced graphene oxide via a DMF–water double solvent system without any addition agent. The dispersed MnO–NiO nanoparticles provide high theoretical capacitance. The uniform growth and attachment of MnO–NiO nanoparticles on the graphene nanosheets offer greatly decreased contact resistance and effective charge transfer. Simultaneously, graphene plays an architecture support role to ensure stable structure. Electrochemical measurement results show that the MNG electrodes deliver a high specific capacitance of 813 F g−1 at 0.5 A g−1, excellent rate capability (80.56% retention at 4 A g−1) and good cycling stability. In the one-step interface approach, the excellent dissolving capacity of DMF allows inorganic salts directly used as reagents in organic phase instead of conventional organic reagents, which fundamentally reduces the internal resistances of the electrode active materials. By virtue of this significant expansion of reagent categories and the convenient experimental accessibility, this improved interface method might be a promising approach to develop other classes of hybrids based on graphene for electrochemical energy storage devices and readily to scale up.
Co-reporter:Shanshan Xiao, Heng Li, Li Liu, Jianshe Lian
Materials Science in Semiconductor Processing 2015 Volume 39() pp:680-685
Publication Date(Web):November 2015
DOI:10.1016/j.mssp.2015.05.051
Assembled mesoporous ZnO sheets that consist of ZnO nanoparticles were prepared by a precursor based route. The microstructure of the as-obtained sample was characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM) and nitrogen adsorption/desorption isotherms. The optical properties were investigated by ultraviolet–visible (UV–vis) spectrophotometer and the photoluminescence spectroscopy. Photocatalytic tests indicated that the sample exhibited highly efficient photodegradation of organic dye under UV light irradiation. The degradation efficiencies of Methyl Orange (MO) reached 98% after irradiation for 30 min, which is comparable to that of P25 TiO2. Furthermore, the sample could be easily separated from the reaction system by sedimentation or filtration. The recycling tests showed no obvious decrease in the activity of our sample, from 100% for the first recycled photodegradation to 95% for the fifth recycle. This confirmed the sample a good reusability. As the mesoporous sheet structure could be easily composite with other materials, this study could provide a promising platform for the fabrication of ZnO-based devices.
Co-reporter:Shu Wang, Lei Zhao, Lina Bai, Junmin Yan, Qing Jiang and Jianshe Lian
Journal of Materials Chemistry A 2014 vol. 2(Issue 20) pp:7439-7445
Publication Date(Web):24 Mar 2014
DOI:10.1039/C4TA00354C
We demonstrate a simple and green synthetic pathway to prepare TiO2–carbon nanoparticles (C/TiO2 NPs) by the sol–gel method, abandoning additional carbon sources but utilizing the organic group in the Ti precursor. Then the C/TiO2 NPs were decarburized under an air atmosphere at 500 °C for 2 h to form the reduced TiO2 nanoparticles. XRD, Raman spectrum, HRTEM and electron energy loss spectrum (EELS) analyses showed that the C/TiO2 NPs were composites of core-shell structured TiO2 and amorphous carbon; and both C/TiO2 and reduced TiO2 NPs contained a large number of oxygen vacancies, which led to structural disorders in them. These structural disorders induced the valence band tails to enhance visible light absorption and to tailor the bandgap structures of the two modified TiO2 samples to match the hydrogen and oxygen production energy levels. As a result, the two structure-disordered C/TiO2 and reduced TiO2 nanocrystals showed excellent solar-driven photocatalytic activities: the C/TiO2 performed best on the photodegradation of phenol and methyl blue, while the reduced TiO2 displayed an excellent hydrogen generation rate, 10 times higher than that of the reference TiO2 by photo-splitting water.
Co-reporter:L. L. Pan, K. K. Meng, G. Y. Li, H. M. Sun and J. S. Lian
RSC Advances 2014 vol. 4(Issue 94) pp:52451-52460
Publication Date(Web):13 Oct 2014
DOI:10.1039/C4RA05141F
Gadolinium and indium co-doped CdO thin films were prepared by a pulsed laser deposition method. The XRD and XPS results indicated that Gd3+ and In3+ ions occupied locations in the interstitial positions and/or Cd2+-ion vacancies in the CdO lattice. The FESEM images showed that the films were homogeneous and consisted of nanograins with a size range of 23–40 nm. The optical band gap of the CdO thin films can be engineered over a wide range of 2.72–3.56 eV by introducing Gd and In dopants. Such transparent semiconducting Gd and In co-doped CdO films were then grown on p-type Si substrates to fabricate n-CdO/p-Si heterojunction devices. The important junction parameters such as the series resistance (Rs), ideality factor (n) and Schottky barrier height (Φb) were determined by analysing different plots from the current density–voltage (J–V) characteristics. The obtained results indicated that the electrical properties of the heterojunction diodes were controlled by the dopant concentration. The p-Si/n-Cd1−x−yGdxInyO heterojunction diode showed the best values of open circuit voltage, Voc = 1.04 V and short circuit current density, Jsc = 11.4 mA cm−2 under an illumination intensity of 100 mW cm−2, which was suitable for solar cell applications.
Co-reporter:Shuang Han, Lei Zhao, Guoyong Wang, Jianshe Lian
Materials Letters 2014 Volume 127() pp:20-23
Publication Date(Web):15 July 2014
DOI:10.1016/j.matlet.2014.04.080
•Significant intragranular dislocation accumulation was observed in nanocrystalline Ni.•Large plastic deformation produced high density of deformation twins.•Dislocation accumulation was enabled primarily by dislocation–twin interactions.•The intrinsic potential of nanocrystalline metals in dislocation storage was disclosed.Lacking of dislocation storage capability has hitherto been considered an intrinsic feature for most nanocrystalline (NC) metals. Only under specific deformation conditions can trapped dislocations be detected inside the nano-grains, such as at liquid-nitrogen temperature or under complicated stress states. Here we show that, contrary to common belief, significant intragranular dislocation accumulation has been observed in NC Ni deformed under conventional uniaxial loading at room temperature. Considerable amount of deformation twins, which were progressively introduced during deformation, were identified to play a key role in pinning and stabilizing these dislocations. These observations disclose the intrinsic potential of NC metals in dislocation storage and may help with achieving high strength and acceptable ductility simultaneously in these materials.
Co-reporter:S. Wang, X.J. Yang, Q. Jiang, J.S. Lian
Materials Science in Semiconductor Processing 2014 Volume 24() pp:247-253
Publication Date(Web):August 2014
DOI:10.1016/j.mssp.2014.03.029
Cu/N-codoped TiO2 nanoparticles were prepared by sol–gel technique. Their structure, surface chemical composition, and optical absorption were characterized. All as-prepared samples consisted of the anatase phase. It was found that Cu atoms replaced Ti atom sites, and N atoms occupied the O atom sites and interstitial sites in the TiO2 lattice. The optical absorption results reveal that Cu/N codoping could greatly enhance the absorption of TiO2 in the entire visible region, leading to a decrease in the band-gap energy of TiO2. It also significantly enhanced the solar-driven catalytic activity of TiO2 in the degradation of methylene blue in solution. The sample 2.0 at% Cu/N-codoped TiO2 displayed the highest solar-driven catalytic efficiency among all tested samples.
Co-reporter:Guoyong Wang
Advanced Engineering Materials 2014 Volume 16( Issue 4) pp:413-420
Publication Date(Web):
DOI:10.1002/adem.201300300
Whether low strain hardening is an intrinsic behavior of nc metals is still an open question. To make clear this issue, in this paper repeated stress relaxation experiments were performed on a nanocrystalline and coarse-grained copper, respectively. The mobile dislocation density during plastic strain, which directly determines the performance of strain hardening, was deduced from this experiment. The mobile dislocation density of nanocrystalline copper decreased much slower than coarse-grained copper. The high mobility of the dislocation in nanocrystalline copper indicate the dislocation seldom interact with each other and generate sessile barrier, and render the nanocrystalline copper a more diminutive strain-hardening capacity than coarse-grained copper.
Co-reporter:L.L. Pan, G.Y. Li, J.S. Lian
Applied Surface Science 2013 Volume 274() pp:365-370
Publication Date(Web):1 June 2013
DOI:10.1016/j.apsusc.2013.03.066
Highlights
- •
Highly textured cerium and gadolinium co-doped CdO films were deposited on glass substrates by RF magnetron sputtering.
- •
The average optical transmittance of co-doped CdO films was over 80% in the UV–vis spectral regions.
- •
The optical band gap of the co-doped CdO films was increased from 2.59 eV to 2.99 eV.
- •
The doped CdO films show low electrical resistivity of 3.11 × 10−4 Ω cm and high carrier concentration of 6.34 × 1020 cm−3.
Co-reporter:S. Wang, L.N. Bai, H.M. Sun, Q. Jiang, J.S. Lian
Powder Technology 2013 Volume 244() pp:9-15
Publication Date(Web):August 2013
DOI:10.1016/j.powtec.2013.03.054
•The TiO2 and Mo-doped TiO2 nanoparticles were prepared by sol-gel route.•The structure of TiO2 was all anatase phase with the crystalline size about 30 nm.•The light absorption was improved efficiently by Mo-doping, even in the visible light region.•The bandgap of TiO2 was narrowed by Mo-doping, corresponding with the analysis of electronic structure.•The photocatalytic activity of TiO2 nanopowders has been promoted by Mo-doping.Mo-doped TiO2 nanoparticles were prepared by sol-gel technique. The as-synthesized samples were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), TEM and FE-SEM. UV–Vis absorption spectrum and the Kubelka–Munk transformation were used to measure the absorption curves and band gap. Their photocatalytic activities were evaluated by the photo-degradation of methyl orange (MO) under irradiation of UV–Visible light and simulated solar light. The results show that Mo6 + ions have been doped into anatase TiO2 lattice. Mo-doping in TiO2 narrows the band gap (from 3.19 eV of TiO2 to 3.05 eV of Ti0.97Mo0.03O2) and efficiently increases the optical absorption in visible range. The density functional theory (DFT) calculation of Ti1-xMoxO2 (x = 0.02) explains that Mo atom behaves as an abundant donor in TiO2 and can narrow the band gap, since it has two more valence electrons. Therefore, Mo-doped TiO2 nanoparticles exhibit improved photo-degradation ability and the optimal ability of TiO2 nanocrystals is achieved by 2.0 at% Mo-doping.The Mo-doped TiO2 nanoparticles exhibit improvements in the photo-degradation of methyl orange under UV–Visible irradiation and simulated solar-driven irradiation, respectively, due to the considerable optical absorption in both UV and visible ranges. For optimum 2.0 at% Mo-doped TiO2, the degrading efficiency enhances more significantly under solar-driven or visible light than under UV light.
Co-reporter:L.N. Bai, Y.P. Wei, J.S. Lian, Q. Jiang
Journal of Physics and Chemistry of Solids 2013 Volume 74(Issue 3) pp:446-451
Publication Date(Web):March 2013
DOI:10.1016/j.jpcs.2012.11.008
Various doping sites of Sn in the In2O3 system have been modeled and simulated by the first-principles. The energy favorable site of Sn in In2O3 is found to be on the b-site, which is consistent with experiments. The doping of Sn into interstitial sites is experimentally possible due to the fluctuation in energy, and the intrinsic oxygen vacancies in In2O3 favor the formation of Sni. As Sni in doped ITO can drastically change the transparency in the visible light range, it is necessary to control the preparatory conditions to avoid Sn doping in interstitial sites for realizing ideal transparency in visible light range. By using the LDA+U approach, the band structures of In2−xSnxO3 (x≤0.125) are calculated, which are in substantially better agreement with the experimental values than previous first-principles results.Highlights► Various doping sites of Sn in In2O3 have been modeled and simulated by the first-principles. ► By using LDA+U approach, the band structures of In2−xSnxO3 (x≤0.125) are calculated. ► The doping of interstitial sites is possible, and the oxygen vacancies favor its formation.
Co-reporter:S. Wang, J.S. Lian, W.T. Zheng, Q. Jiang
Applied Surface Science 2012 Volume 263() pp:260-265
Publication Date(Web):15 December 2012
DOI:10.1016/j.apsusc.2012.09.040
Abstract
Anatase and rutile TiO2 composite nanopowders with different Fe-doped concentrations were synthesized by sol–gel technique. X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) were used to detect the crystalline structure and chemical state of the nanopowders. The photocatalytic activity was estimated by the degradation of 20 mg/L methyl orange under an irradiation of 350–450 nm light source. TiO2 powder with 28.76 wt% rutile showed the highest degradation among the TiO2 composite powders, but the 1.0 at% Fe-doping TiO2 with 20.64 wt% rutile phase exhibited an even higher degradation than that without Fe doping. Doping of Fe in TiO2 composite powder induced an evident increase in absorption peak and a significant red-shift in absorption edge from 420 nm to 460 nm in UV–vis absorption spectrum, and these characteristics are responsible for the improvement of photocatalytic activity.
Co-reporter:J. Sudagar, J.S. Lian, Q. Jiang, Z.H. Jiang, G.Y. Li, R. Elansezhian
Progress in Organic Coatings 2012 Volume 74(Issue 4) pp:788-793
Publication Date(Web):August 2012
DOI:10.1016/j.porgcoat.2011.10.022
Magnesium and its alloys corrode rapidly in the electrolyte bath. Surfactants while used extensively as surface active agents in the electrolyte bath, have been little studied on magnesium surfaces. The influence of surfactants cetyltrimethyl ammonium bromide (CTAB) and sodium lauryl sulfate (SLS) on the surface properties such as roughness, morphology and topography of electroless Ni–P deposits on magnesium alloy was researched. The research reveals that the surfactant solutions has significant influence on the composition of coating, surface roughness and surface morphology. In addition, it has marginal effect on the microhardness. Electroless coatings with addition of surfactants produce a smooth surface and average roughness value of 1.412 μm for CTAB and 1.789 μm for SLS, which are less than the value (2.98 μm) without surfactant addition. There was a significant improvement in the rate of deposition. However, the surfactants influence reached maximum at critical micelle concentration and above this value it gets stabilized. The initial structure appears to be dependent upon the percent occluded surfactants. The surface microstructures are discussed in line with the experimental observations.
Co-reporter:J.H. Zheng, J.L. Song, Q. Jiang, J.S. Lian
Applied Surface Science 2012 Volume 258(Issue 18) pp:6735-6738
Publication Date(Web):1 July 2012
DOI:10.1016/j.apsusc.2012.03.010
Abstract
Y-doped ZnO (Zn1−xYxO) nanoparticles with different Y concentrations were synthesized by sol–gel method. The effects of Y concentration on the optical properties of the as-synthesized Zn1−xYxO nanoparticles were investigated. Photoluminescence (PL) measurements revealed that doping of Y in ZnO induced an evidence increase of UV emission. At Y concentration x = 0.07, the UV emission intensity reached maximum, which is about 9 times higher than that of the compared pure ZnO nanoparticles. Exceeding this concentration, the formation of Y2O3 causes a decrease in the UV emission intensity. This enhanced UV emission enables Zn1−xYxO system potential applications in supersensitive UV detector sinimaging, photosensing, and intrachip optical interconnects.
Co-reporter:L.N. Bai, B.J. Zheng, J.S. Lian, Q. Jiang
Solid State Sciences 2012 Volume 14(Issue 6) pp:698-704
Publication Date(Web):June 2012
DOI:10.1016/j.solidstatesciences.2012.03.018
Zn1−xCdxO thin films are deposited on quartz substrate by pulse laser deposition. Their band structure and optical properties are experimentally and theoretically investigated. By varying Cd concentration, the band gap of Zn1−xCdxO films can be adjusted in a wide range from 3.219 eV for ZnO to 2.197 eV for Zn0.5Cd0.5O, which produces different emissions from ultraviolet to Kelly light in their photoluminescence spectra. Simultaneity, the electronic structure and band gap of Zn1−xCdxO are investigated by the density functional theory (DFT) with a combined generalized gradient approximation (GGA) plus Hubbard U approach, which precisely predicts the band-gaps of ZnO and Zn1−xCdxO alloys. Both the experimental results and theoretical simulation reveal that with increasing Cd concentration in Zn1−xCdxO alloys, their absorption coefficients in visible light range are evidently enhanced. The adjustable photoluminescence emission and enhanced visible light absorption endow Zn1−xCdxO alloys potential applications in optoelectronic and photocatalytic fields.Graphical abstractHighlights► A combined experimental and theoretical model investigated for Cd-doped ZnO thin films. ► Our results show that Cd-doped ZnO is n-type impurity dopants, CdO and Cdi are donors and they can compensate p-type doping. ► The experimental observed very wide visible light emission may be attributed to the crystalline defects introduced by Cd doping. ► The optical band gap and optical transition of ZnO and Zn1−xCdxO alloys have been accurately reproduced by GGA + U approach.
Co-reporter:Jiahong Zheng, Jiling Song, Qing Jiang, Jianshe Lian
Journal of Materials Science & Technology 2012 Volume 28(Issue 2) pp:103-108
Publication Date(Web):February 2012
DOI:10.1016/S1005-0302(12)60029-2
Co-reporter:J. H. Zheng;J. L. Song;Z. Zhao;Q. Jiang ;J. S. Lian
Crystal Research and Technology 2012 Volume 47( Issue 7) pp:713-718
Publication Date(Web):
DOI:10.1002/crat.201200026
Abstract
Nd-doped ZnO nanoparticles with different concentration were synthesized by sol-gel method. The structures, magnetic and optical properties of as-synthesized nanorods were investigated. X-ray diffraction (XRD) and x-ray photoelectron spectroscopy (XPS) results demonstrated that Nd ions were incorporated into ZnO lattice; but Zn1-xNdxO nanoparticles with Nd concentration of x = 0.05 showed Nd2O3 phase, so the saturation concentration of Nd in Zn1-xNdxO is less than 5 at%. Vibrating sample magnetometer (VSM) measurements indicated that Nd doped ZnO possessed dilute ferromagnetis behaviour at room temperature. Photoluminescence spectroscopy (PL) showed that Nd ions doping induced a red slight shift and decrease in UV emission with increase of Nd concentration.
Co-reporter:J. H. Zheng;J. L. Song;Q. Jiang
Journal of Materials Science: Materials in Electronics 2012 Volume 23( Issue 8) pp:1521-1526
Publication Date(Web):2012 August
DOI:10.1007/s10854-012-0622-z
Zn1−xCuxO nanoparticles were synthesized by using sol–gel method. Structure and optical properties of Zn1−xCuxO nanoparticles were studied experimentally and theoretically. The simulations are based upon the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional theory. The results showed that the UV emission is effectively quenched and the emission in visible-light region is enhanced by Cu-doping, which are theoretically explained to be attributed to the electronic intra-band transition from the occupied bands to the unoccupied ones under irradiation. Therefore, Zn1−xCuxO system may be a potential candidate for photocatalytic in visible light range.
Co-reporter:J.H. Zheng, Q. Jiang, J.S. Lian
Applied Surface Science 2011 Volume 258(Issue 1) pp:93-97
Publication Date(Web):15 October 2011
DOI:10.1016/j.apsusc.2011.08.012
Abstract
ZnO nanorods with uniform diameter and length have been synthesized on an indium-tin oxide (ITO) substrate by using a simple thermal evaporation method which is suitable to larger scale production and without any catalyst or additives. The samples were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM), ultraviolet–vis (UV–vis) absorption spectrum, photoluminescence (PL) spectrum and Raman spectrum. The single-phase ZnO nanorods grow well-oriented along the c-axis of its wurtzite structure on ITO substrate. The ZnO nanorods shows sharp and strong UV emission located at 380 nm without notable visible light emission in the PL spectrum, which suggests the good crystallinity of the nanorods, which was also testified by their Raman spectrum. The photodegradation of methylene orange (MO) in aqueous solution reveals that the well-arranged c-axis growth of ZnO nanorods possess evidently improved photocatalytic performance and these properties enable the ZnO nanorods potential application in UV laser.
Co-reporter:B.J. Zheng, J.S. Lian, L. Zhao, Q. Jiang
Applied Surface Science 2011 Volume 257(Issue 13) pp:5657-5662
Publication Date(Web):15 April 2011
DOI:10.1016/j.apsusc.2011.01.070
Abstract
Ternary polycrystalline Zn1−xCdxO semiconductor films with cadmium content x ranging from 0 to 0.23 were obtained on quartz substrate by pulse laser deposited (PLD) technique. X-ray diffraction measurement revealed that all the films were single phase of wurtzite structure grown on c-axis orientation with its c-axis lattice constant increasing as the Cd content x increasing. Atomic force microscopy observation revealed that the grain size of Zn1−xCdxO films decreases continuously as the Cd content x increases. Both photoluminescence and optical measurements showed that the band gap decreases from 3.27 to 2.78 eV with increasing the Cd content x. The increase in Cd content x also leads to the broadening of the emission peak. The resistivity of Zn1−xCdxO films decreases evidently for higher values of Cd content x. The shift of PL emission to visible light as well as the decrease of resistivity makes the Zn1−xCdxO films potential candidate for optoelectronic device.
Co-reporter:J.H. Zheng, Q. Jiang, J.S. Lian
Applied Surface Science 2011 Volume 257(Issue 11) pp:5083-5087
Publication Date(Web):15 March 2011
DOI:10.1016/j.apsusc.2011.01.025
Abstract
Flower-like ZnO nanorods have been synthesized by heating a mixture of ZnO/graphite powders using the thermal evaporation and vapor transport on Si (1 0 0) substrates without any catalyst. The structures, morphologies and optical properties of the products were characterized in detail by using X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and Raman spectroscopy. The synthesized products consisted of large quantities of flower-like ZnO nanostructures in the form of uniform nanorods. The flower-like ZnO nanorods had high purity and well crystallized wurtzite structure, whose high crystalline quality was proved by Raman spectroscopy. The as-synthesized flower-like ZnO nanorods showed a strong ultraviolet emission at 386 nm and a weak and broad yellow–green emission in visible spectrum in its room temperature photoluminescence (PL) spectrum. In addition, the growth mechanism of the flower-like ZnO nanorods was discussed based on the reaction conditions.
Co-reporter:J. H. Zheng;J. L. Song;X. J. Li;Q. Jiang ;J. S. Lian
Crystal Research and Technology 2011 Volume 46( Issue 11) pp:1143-1148
Publication Date(Web):
DOI:10.1002/crat.201100397
Abstract
Zn1-xCux O powders were synthesized by using sol-gel method. Electronic band structure and ferromagnetic properties of Zn1-xCux O powders were studied experimentally and theoretically. The simulations are based upon the Perdew-Burke-Ernzerhof form of generalized gradient approximation within the density functional theory. Zn1-xCux O shows dilute ferromagnetism, as a saturated magnetization of 0.9×10-3emu/g was observed for Zn0.95Cu0.05O powders. The strong p -d hybridization between Cu and its four neighbouring O atoms is responsible for the ferromagnetism. Comparing with ZnO whose Fermi level locates at the valence band maximum, the Fermi level of the Zn1-xCux O shifts upward into the valence band and hence the Zn1-xCux O system exhibits theoretically a p -type metallic semiconducting property. The Zn1-xCux O system may be a potential candidate in spintronics. (© 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Co-reporter:B.J. Zheng, J.S. Lian, L. Zhao, Q. Jiang
Vacuum 2011 Volume 85(Issue 9) pp:861-865
Publication Date(Web):25 February 2011
DOI:10.1016/j.vacuum.2011.01.002
Transparent tin-doped cadmium oxide (Sn–CdO) thin films with different Sn concentration were deposited on quartz glass substrates by pulse laser deposition (PLD) at 400 °C. The film’s crystallographic structure, optical and electrical properties were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FE-SEM), UV–VIS spectrophotometer and Hall system. Results show that doping of Sn enhances the film’s [111] preferred orientation and causes slight shift in the (200) Bragg angle towards higher value. The optical band gaps (Eg) of the Sn-doped films were found to increase with the increase of Sn doping concentration. In addition, proper doping of Sn evidently improves the electrical properties of CdO, such as the resistivity of the CdO film with 2.9 at% Sn doping is about one-twelfth of that of the CdO film, while the carrier concentration is about 13 times of that of the undoped. The improvements both in optical and electrical properties endow that the Sn–CdO thin films have potential application as TCO material for different optoelectronic device applications.Research highlights► In this study, Sn doped CdO films were deposited on quartz substrates by pulse laser deposition at the substrate temperature of 400 °C, and the effect of Sn doping concentration on the structural, optical and electrical properties of CdO films were investigated. ► The moderate Sn doping CdO film (Sn concentration of 2.9 at%) shows high carrier concentration of 4.53 × 1020 cm−3 and low electric resistivity of 1.59 × 10−4 Ω cm. ► All Sn–CdO thin films show a high optical transmission and a shift of Eg to higher energies. For their improved optical and electrical properties, Sn–CdO thin film could be an excellent candidate for future optoelectronic devices.
Co-reporter:B.J. Zheng, X.M. Chen, J.S. Lian
Optics and Lasers in Engineering 2010 Volume 48(Issue 5) pp:526-532
Publication Date(Web):May 2010
DOI:10.1016/j.optlaseng.2010.01.001
Al+SiC powders were pulse-laser (Nd–YAG) cladded on AZ91D magnesium alloy. The microstructure, chemical composition and phase analyses of the cladding layer were studied by scanning electron microscopy, EDX analysis, and X-ray diffraction measurement. The composite coating is composed of SiC and β-Mg17Al12 phases. The laser cladding showed very good bonding with the magnesium alloy substrate. The surface hardness of cladding coating is higher than that of substrate and increases with the increase of SiC content in the cladding. Sliding wear tests conducted in a pin-on-disc wear testing apparatus showed that the composite coating with SiC particles and in situ synthesized Mg17Al12 phase remarkably improved the wear resistance of the AZ91D magnesium alloy.
Co-reporter:Guoyong Wang, Guangyu Li, Lei Zhao, Jianshe Lian, Zhonghao Jiang, Qing Jiang
Materials Science and Engineering: A 2010 527(16–17) pp: 4270-4274
Publication Date(Web):
DOI:10.1016/j.msea.2010.03.076
Co-reporter:Xiaoming Chen, Guangyu Li, Jianshe Lian, Qing Jiang
Surface and Coatings Technology 2009 204(5) pp: 736-747
Publication Date(Web):
DOI:10.1016/j.surfcoat.2009.09.022
Co-reporter:H. Zhang;Z. Jiang;J. Lian ;Q. Jiang
Advanced Engineering Materials 2008 Volume 10( Issue 1-2) pp:41-45
Publication Date(Web):
DOI:10.1002/adem.200700237
Co-reporter:X. Shen;J. Lian;Z. Jiang ;Q. Jiang
Advanced Engineering Materials 2008 Volume 10( Issue 6) pp:539-546
Publication Date(Web):
DOI:10.1002/adem.200800009
Co-reporter:Guangyu Li;Liyuan Niu;Qing Jiang
Journal of Wuhan University of Technology-Mater. Sci. Ed. 2008 Volume 23( Issue 1) pp:60-64
Publication Date(Web):2008 February
DOI:10.1007/s11595-006-1060-7
A technology for electroless Ni-P deposition on AZ91D from a low cost plating bath containing sulfate nickel was proposed. The seal pretreatment was employed before the electroless Ni-P deposition for the sake of occluding the micro holes of the cast magnesium alloy and interdicting the bubble formation in the Ni-P coating during plating process. And pickling pretreatment can provide a better adhesion between the Ni-P deposition and AZ91D substrate. The deposition speed of the Ni-P coating is 29 μm/h. The technology is employed to AZ91D magnesium alloy automobile parts and can provide high hardness and high wear-resistant. The weight losses of Ni-P plated and heat-treated Ni-P plated magnesium alloy specimen are only about 1/6 and 1/10 that of bare magnesium alloy specimen after 10 min abrasion wear, respectively. The hardness of the electroless Ni-P plated brake pedal support brackets is 674.1 VHN and 935.7 VHN after 2 hours heat treatments at 180 °. The adhesion of Ni-P coatings on magnesium alloy substrates meets the demands of ISO Standards 2819. The technology is environment friendly and cannot cause hazard to environment because of absence of chromate in the whole process.
Co-reporter:Jing Yang, Haizan Bai, Qing Jiang, Jianshe Lian
Thin Solid Films 2008 Volume 516(Issue 8) pp:1736-1742
Publication Date(Web):29 February 2008
DOI:10.1016/j.tsf.2007.05.034
To use solar irradiation or interior lighting efficiently, we sought a photocatalyst with high reactivity under visible light. Nitrogen and carbon doping TiO2 films were obtained by heating a TiO2 gel in an ionized N2 gas. The as-synthesized TiO2−x−yNxCy films have shown an improvement over titanium dioxide in optical absorption and photocatalytic activity such as photodegradation of methyl orange under visible light. The process of the oxygen atom substituted by nitrogen and carbon was discussed. Oxygen vacancy induced by the formation of Ti3+ species and nitrogen and carbon doped into substitution sites of TiO2 have been proven to be indispensable for the enhance of photocatalytic activity, as assessed by UV–Vis Spectroscopy and X-ray photoemission spectroscopy.
Co-reporter:Lei Zhao, Mandi Han, Jianshe Lian
Thin Solid Films 2008 Volume 516(Issue 10) pp:3394-3398
Publication Date(Web):31 March 2008
DOI:10.1016/j.tsf.2007.10.102
Transparent TiO2 films with typical anatase structure were prepared by pulsed laser ablated titanium (99.99%) target onto quartz glass substrates at 700 °C in oxygen pressure of 10 Pa. The as-deposited films were then annealed at 800 °C in an oxygen atmosphere for different time to produce films with mixed anatase and rutile structures. The titanium dioxide (TiO2) films with mixed anatase and rutile structures show higher photocatalytic efficiency than the film with only anatase structure. The highest visible-light photocatalytic efficiency of 64% was observed from the film with 33% rutile phase. TiO2 films with mixed structures exhibit lower band energy. The high photocatalytic efficiency of the films with mixed structures was explained by the increasing excitation in visible-light region and the restraining of the recombination of electrons and holes, which increase the absorption of the surface organic or inorganic species during the photocatalytic process.
Co-reporter:Changdong Gu, Jun Li, Jianshe Lian, Guoqu Zheng
Applied Surface Science 2007 Volume 253(Issue 17) pp:7011-7015
Publication Date(Web):30 June 2007
DOI:10.1016/j.apsusc.2007.02.024
Abstract
ZnO thin films were electrochemically deposited onto the ITO-coated glass substrate from an electrolyte consisted of 0.1 M Zn(NO3)2 aqueous solution at 65 ± 1 °C. A compact ZnO film with (0 0 2) preferred orientation was obtained at the applied potential of −1.3 V for 1200 s. It was also found that the morphology of the ZnO films grown at the potential of −1.3 V was characterized of single or coalescent hexagonal platelets. However, the ZnO crystals grown at the potential of −2.0 V was changed to be a bimodal size distribution. The band gap energy of the as deposited ZnO films, about 3.5 eV, was independent of both the applied potential and the deposition time, respectively. The minor amount of Zn(OH)2 might be co-deposited with the formation of ZnO revealed by the FT-IR spectroscopy. Three strategies to improve the ZnO crystal quality based on the photoluminescence properties were proposed in the paper, which were (a) adopting the lower deposition potential, (b) increasing the deposition time at a certain potential, and (c) annealing after as-deposition, respectively.
Co-reporter:Yaodong Liu, Jianshe Lian
Applied Surface Science 2007 Volume 253(Issue 7) pp:3727-3730
Publication Date(Web):30 January 2007
DOI:10.1016/j.apsusc.2006.08.012
Abstract
Transparent aluminum-doped zinc oxide (AZO) thin films were deposited on quartz glass substrates by pulsed laser deposition (PLD) from ablating Zn–Al metallic targets. The structural, electrical and optical properties of these films were characterized as a function of Al concentration (0–8 wt.%) in the target. Films were deposited at a low substrate temperature of 150 °C under 11 Pa of oxygen pressure. It was observed that 2 wt.% of Al in the target (or 1.37 wt.% of Al doped in the AZO film) is the optimum concentration to achieve the minimum film resistivity and strong ultraviolet emission. The presence of Al in the ZnO film changes the carrier concentration and the intrinsic defects.
Co-reporter:Changdong Gu, Jianshe Lian, Qing Jiang, Zhonghao Jiang
Materials Science and Engineering: A 2007 Volume 459(1–2) pp:75-81
Publication Date(Web):25 June 2007
DOI:10.1016/j.msea.2006.12.093
A ductile–brittle–ductile transition in the fracture mode of the Ni–8.6 wt.% Co alloy with an average grain size of 13 nm was observed through increasing the strain rates from 1.04 × 10−5 to 1.04 s−1 at room temperature (RT). The Ni–Co alloy exhibited a limited plastic strain (about 1%) at the intermediate strain rates of 2.08 × 10−3 to 4.17 × 10−2 s−1, which was attributed to that in this strain rate range less dislocations or GB atoms would be activated. However, a gradual brittle–ductile transition occurred with the strain rate decreasing from 2.08 × 10−3 to 1.04 × 10−5 s−1. The lower strain rates allow the GB atoms diffuse easily, which would relax the stress concentration and hence enhance the ductility. Another brittle–ductile transition happened with increasing the strain rates from 4.17 × 10−2 to 1.04 s−1. The enhanced ductility at high strain rate can be explained by stress-assisted activation of GB atoms.
Co-reporter:G. Y. Li;J. S. Lian;L. Y. Niu;Z. H. Jiang
Advanced Engineering Materials 2006 Volume 8(Issue 1‐2) pp:
Publication Date(Web):13 FEB 2006
DOI:10.1002/adem.200500095
Co-reporter:C. Gu;J. Lian;Z. Jiang
Advanced Engineering Materials 2006 Volume 8(Issue 4) pp:
Publication Date(Web):3 APR 2006
DOI:10.1002/adem.200500197
Co-reporter:Changdong Gu, Jianshe Lian, Jinguo He, Zhonghao Jiang, Qing Jiang
Surface and Coatings Technology 2006 Volume 200(18–19) pp:5413-5418
Publication Date(Web):8 May 2006
DOI:10.1016/j.surfcoat.2005.07.001
Nanocrystalline (nc) Ni coating was direct-current electrodeposited on the AZ91D magnesium alloy substrate aimed to improve its corrosion resistance using a direct electroless plating of nickel as the protective layer. As comparison, two electroless Ni coatings on the magnesium alloy with different thickness were also presented in the paper. The surface morphologies of the coatings were studied by SEM and FESEM. The nc Ni coating had an average grain size of about 40 nm and an evident {200} preferred texture revealed by XRD. The hardness of the nc Ni coating was about 580 VHN, which was far higher than that (about 100 VHN) of the AZ91D magnesium alloy substrate. The electrochemical measurements showed that the nc Ni coating on the magnesium alloy had the lowest corrosion current density and most positive corrosion potential among the studied coatings on the magnesium alloy. Furthermore, the nc Ni coating on the AZ91D magnesium alloy exhibited very high corrosion resistance in the rapid corrosion test illustrated in the paper. The reasons for an increase in the corrosion resistance of the nc Ni coating on the magnesium alloy should be attributable to its fine grain structure and the low porosity in the coating.
Co-reporter:J.S. Lian, G.Y. Li, L.Y. Niu, C.D. Gu, Z.H. Jiang, Q. Jiang
Surface and Coatings Technology 2006 Volume 200(20–21) pp:5956-5962
Publication Date(Web):22 May 2006
DOI:10.1016/j.surfcoat.2005.09.007
An electroless Ni–P deposition process has been developed to treat the AZ91D magnesium alloy surfaces against corrosion. Magnesium alloy AZ91D was first phosphatized in a zinc phosphating bath containing molybdate. Then an electroless Ni–P deposition was carried out on the phosphate coating from a sulfate solution. The phases in the phosphate coatings were analyzed by XRD. Microstructures of phosphate coatings and electroless Ni–P depositions were observed by SEM and EDS. It was found that there was metallic zinc in the phosphate coating and the addition of Na2MoO4 in the phosphating bath resulted in the increase of zinc in the coating. A lot of disperse metallic zinc particles acted as the catalyst nuclei for the succeeding Ni–P deposition. Consequently, the Ni–P depositions with dense and fine microstructure were obtained on the phosphate coatings gained from the phosphating bath wherein 2.0∼2.5g/L Na2MoO4 was added. The Ni–P plus phosphate coatings on the AZ91D magnesium alloy exhibited acceptable corrosion resistance as shown by the results of the Salt Spray Corrosion Test.
Co-reporter:Yaodong Liu, Lei Zhao, Jianshe Lian
Vacuum 2006 Volume 81(Issue 1) pp:18-21
Publication Date(Web):16 September 2006
DOI:10.1016/j.vacuum.2006.02.001
Polycrystalline Al-doped ZnO films with good photoluminescence property were successfully deposited on quartz glass substrates by pulsed laser deposition (PLD) at room temperature. The films were obtained by ablating a metallic target (Zn:Al 3 wt%) at various laser energy densities (1.0–2.1 J/cm2) in oxygen atmosphere (9 Pa). The structure of the films was characterized by XRD. Ultraviolet photoluminescence centered at 359–361 nm was observed in the room temperature PL spectra of the Al-doped ZnO films.
Co-reporter:C. Gu;J. Lian;Z. Jiang
Advanced Engineering Materials 2005 Volume 7(Issue 11) pp:
Publication Date(Web):28 NOV 2005
DOI:10.1002/adem.200500136
Co-reporter:Xijia Yang, Lijun Zhao, Jianshe Lian
Journal of Power Sources (1 March 2017) Volume 343() pp:373-382
Publication Date(Web):1 March 2017
DOI:10.1016/j.jpowsour.2017.01.078
•Hierarchical nickel sulfides/MoS2 (NMS) nanosheet supported on CNT was fabricated.•NMS/CNT//AC asymmetric supercapacitor delivers high energy density of 40 Wh kg−1.•The asymmetric supercapacitor shows excellent cycle stability for 10,000 cycles.One-dimensional (1D) hierarchical structures composed of nickel sulfides/MoS2 (NMS) supported on carbon nanotube (CNT) are fabricated through a one-step facile glucose-assisted hydrothermal method (NMS/CNT). The curled and tangled 1D structure is intertwined with each other and constructs three-dimensional (3D) porous networks, providing easy access of electrolyte. Meanwhile, the formation of metallic 1T-2H hybridized MoS2 and the synergistic effect between the MoS2 layers and nickel sulfides (NS) nanoparticles promotes the ions diffusion on the surface of the electrode, and the void space formed between NMS sheets can endure volume change in redox process for more stable structures. Therefore, the assembled NMS/CNT//activated carbon (AC) asymmetric supercapacitor manifests favorable specific capacitance of 108 F g−1 at 0.5 A g−1, along with a high energy density of 40 Wh kg−1 and good cycling stability of almost 100% capacity maintained after 10,000 cycles, implying it's the promising candidate for energy storage.
Co-reporter:Xiaobing Wang, Jiangjiang Hu, Weidong Liu, Guoyong Wang, Jian An and Jianshe Lian
Journal of Materials Chemistry A 2015 - vol. 3(Issue 46) pp:NaN23344-23344
Publication Date(Web):2015/10/06
DOI:10.1039/C5TA07169K
To avoid aggregation in the production of the active electrode material, Ni–Zn system materials (NixZn1−xOH, NiO–ZnO and NixZn1−xS) were synthesized by using a belt reaction zone model, and then were characterized systematically in this work. Among these materials, NixZn1−xS porous spheroid nanoparticles with diameters ∼30 nm possess abundant interconnected micropores caused by the Kirkendall effect in the synthesis, leading to a high surface area of 148.4 m2 g−1 and special paths for ion diffusion. In the three-electrode system testing, NixZn1−xS porous spheroid nanoparticles show the highest specific capacitance of 1867 F g−1 at a current density of 1 A g−1, as well as excellent rate capability and cycling stability. Using NixZn1−xS as the positive electrode and active carbon as the negative electrode, the asymmetric supercapacitor device exhibits an excellent electrochemical performance. The results provide us with a modified method to synthesize metal hydroxides, oxides and sulfides, in order to obtain materials with high supercapacitor performance.
Co-reporter:Haiming Sun, Xijia Yang, Lishu Zhang, Lijun Zhao and Jianshe Lian
Journal of Materials Chemistry A 2017 - vol. 5(Issue 17) pp:NaN8107-8107
Publication Date(Web):2017/03/30
DOI:10.1039/C7TA00578D
Herein, a novel method was developed to synthesize a CoNi binary metal/Co–Ni oxide@carbon (M/MO@C-600) composite by sintering CoNi nanoparticles with Congo Red (CR) at 600 °C and under a N2 atmosphere; this composite was then utilized to prepare electrode materials. Herein, C and O originated from the CR molecule. The M/MO@C-600 composite with a flaky structure delivered a capacitance of 1134.9 F g−1 at 1 A g−1 and a cycling stability with 66% retention even at the high current density of 10 A g−1 after 2000 cycles. Furthermore, a simple asymmetric supercapacitor (ASC) was developed with the M/MO@C-600 composite as the positive electrode material and commercial activated carbon as the negative electrode material. A high specific capacitance of 111.2 F g−1 (at 0.5 A g−1) and excellent energy density of 44.6 W h kg−1 (at 0.425 kW kg−1) were obtained for the ASC device, and 100% capacitance was retained even after 10000 cycles at 6 A g−1. This method for the preparation of electrode materials may facilitate to simultaneously relieve the environmental and energy pressure.
Co-reporter:Haiming Sun, Xijia Yang, Lijun Zhao, Tianhao Xu and Jianshe Lian
Journal of Materials Chemistry A 2016 - vol. 4(Issue 24) pp:NaN9465-9465
Publication Date(Web):2016/05/23
DOI:10.1039/C6TA02126C
Here we report a flexible one-pot hydrothermal synthesis of an octahedral CoFe/CoFe2O4 submicron composite used as a superior Fenton-like catalyst for the decomposition of organic pollutants in water. As a peroxymonosulfate (PMS) catalyst, the non-toxic CoFe/CoFe2O4 submicron composite can highly efficiently decompose Orange II (30 mg L−1, 1.5 min and 60 mg L−1, 3 min). Especially, the CoFe/CoFe2O4 submicron composite exhibits better generalization for the degradation of different organic pollutants and excellent reusability due to its large size and structural stability. Furthermore, its high saturation magnetization (123.7 emu g−1) makes it convenient to magnetically separate from aqueous phase after catalysing the reaction, and its relatively large size is conducive to solving or minimizing secondary pollution. Meanwhile, the probable mechanism of PMS activation with CoFe/CoFe2O4 catalyst is proposed.
Co-reporter:Shu Wang, Lei Zhao, Lina Bai, Junmin Yan, Qing Jiang and Jianshe Lian
Journal of Materials Chemistry A 2014 - vol. 2(Issue 20) pp:NaN7445-7445
Publication Date(Web):2014/03/24
DOI:10.1039/C4TA00354C
We demonstrate a simple and green synthetic pathway to prepare TiO2–carbon nanoparticles (C/TiO2 NPs) by the sol–gel method, abandoning additional carbon sources but utilizing the organic group in the Ti precursor. Then the C/TiO2 NPs were decarburized under an air atmosphere at 500 °C for 2 h to form the reduced TiO2 nanoparticles. XRD, Raman spectrum, HRTEM and electron energy loss spectrum (EELS) analyses showed that the C/TiO2 NPs were composites of core-shell structured TiO2 and amorphous carbon; and both C/TiO2 and reduced TiO2 NPs contained a large number of oxygen vacancies, which led to structural disorders in them. These structural disorders induced the valence band tails to enhance visible light absorption and to tailor the bandgap structures of the two modified TiO2 samples to match the hydrogen and oxygen production energy levels. As a result, the two structure-disordered C/TiO2 and reduced TiO2 nanocrystals showed excellent solar-driven photocatalytic activities: the C/TiO2 performed best on the photodegradation of phenol and methyl blue, while the reduced TiO2 displayed an excellent hydrogen generation rate, 10 times higher than that of the reference TiO2 by photo-splitting water.
Co-reporter:Xiaobing Wang, Jin Hao, Yichang Su, Fanggang Liu, Jian An and Jianshe Lian
Journal of Materials Chemistry A 2016 - vol. 4(Issue 33) pp:NaN12939-12939
Publication Date(Web):2016/07/23
DOI:10.1039/C6TA04022E
Multi-layer NixZn1−xS/Ni foam composites were synthesized by the facile method of a one-step hydrothermal reaction on a frame of Ni foam. The Zn element plays a critical role in constructing the multi-layer nanostructure. In particular, various layers with different morphologies work with good synergistic effect to provide an excellent electrochemical performance. The as-synthesized Ni1−xZnxS/Ni foam-2 h electrode shows a high specific capacitance (1815 F g−1 at 1 A g−1) and outstanding rate properties (1050 F g−1 at 100 A g−1 and 50.1% rate retention over 200 A g−1). Moreover, a two-electrode Ni1−xZnxS/Ni foam-2 h//active carbon–graphene (AC–G) asymmetric supercapacitor device was fabricated and it delivers both a high specific energy density and an excellent cycling stability. The strategy presented here for constructing multi-layer structures is facile and effective, and could be expanded as a general method.
