Co-reporter:Wen-Jing Lu, Shi-Ze Huang, Ling Miao, Ming-Xian Liu, ... Li-Hua Gan
Chinese Chemical Letters 2017 Volume 28, Issue 6(Volume 28, Issue 6) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.cclet.2017.04.007
We demonstrate a simple and highly efficient strategy to synthesize MnO2/nitrogen-doped ultramicroporous carbon nanospheres (MnO2/N-UCNs) for supercapacitor application. MnO2/N-UCNs were fabricated via a template-free polymerization of resorcinol/formaldehyde on the surface of phloroglucinol/terephthalaldehyde colloids in the presence of hexamethylenetetramine, followed by carbonization and then a redox reaction between carbons and KMnO4. As-prepared MnO2/N-UCNs exhibits regular ultramicropores, high surface area, nitrogen heteroatom, and high content of MnO2. A typical MnO2/N-UCNs with 57 wt.% MnO2 doping content (denoted as MnO2(57%)/N-UCNs) makes the most use of the synergistic effect between carbons and metal oxides. MnO2(57%)/N-UCNs as a supercapacitor electrode exhibits excellent electrochemical performance such as a high specific capacitance (401 F/g at 1.0 A/g) and excellent charge/discharge stability (86.3% of the initial capacitance after 10,000 cycles at 2.0 A/g) in 1.0 mol/L Na2SO4 electrolyte. The well-designed and high-performance MnO2/N-UCNs highlight the great potential for advanced supercapacitor applications.A simple and highly efficient strategy to synthesize MnO2/nitrogen-doped ultramicroporous carbon nanospheres (MnO2/N-UCNs) was demonstrated. MnO2/N-UCNs have regular ultramicropores, high surface area, nitrogen heteroatom, and high content of MnO2, and thus exhibit excellent electrochemical performance for supercapacitor electrodes.Download high-res image (346KB)Download full-size image
Co-reporter:Ling Miao, Hui Duan, Mingxian Liu, Wenjing Lu, Dazhang Zhu, Tao Chen, Liangchun Li, Lihua Gan
Chemical Engineering Journal 2017 Volume 317(Volume 317) pp:
Publication Date(Web):1 June 2017
DOI:10.1016/j.cej.2017.02.110
•A simple synthesis of N, S-codoped ultramicroporous carbon nanoparticles (N/S-UCNs) is demonstrated.•Poly(ionic liquid) acts as C, N and S sources, and a self-template to generate ultramicropores.•N/S-UCNs exhibit nanoscale geometry, uniform ultramicropores, high surface area and functional heteroatoms.•N/S-UCNs show high capacitance, excellent rate capability and cycle stability.We demonstrate a highly efficient strategy to synthesize N, S-codoped ultramicroporous carbon nanoparticles (N/S-UCNs) via simple polymerization and carbonization of an ionic liquid (IL). By chemical oxidative polymerization of p-phenylenediamine sulfate ([pPD][2HSO4]) using ammonium persulfate as an initiator, poly(ionic liquid) (PIL) of p[pPD][2HSO4] is obtained, and it acts not only as carbon, nitrogen and sulfur sources, but also as a self-template to generate regular ultramicropores during carbonization. As-prepared N/S-UCNs have nanoscale morphology, uniform ultramicropores (0.50–0.59 nm), high surface area (505–1018 m2 g−1), and high doping content of heteroatoms (N and S). The N/S-UCN carbonized at 600 °C (denoted as N/S-UCN600) achieves an optimum balance between specific surface area and high heteroatom doping content, which exhibits good electrochemical performance when it was used as electrode for supercapacitors. N/S-UCN600 electrode shows a high specific capacitance (225 F g−1 at 2.0 A g−1), long-term cycle stability (90.8% retention after 10,000 cycles), and excellent rate capability (160 F g−1 at 20 A g−1) in alkaline electrolyte. The present PIL-derived strategy to fabricate carbon nanoparticles can be easily carried out without any pretreatment, template or activation procedure, which highlights new opportunity to design heteroatom-doped carbons for advanced energy storage applications.Download high-res image (74KB)Download full-size image
Co-reporter:Ling Miao, Dazhang Zhu, Yunhui Zhao, Mingxian Liu, Hui Duan, Wei Xiong, Quanjing Zhu, Liangchun Li, Yaokang Lv, Lihua Gan
Microporous and Mesoporous Materials 2017 Volume 253(Volume 253) pp:
Publication Date(Web):15 November 2017
DOI:10.1016/j.micromeso.2017.06.032
•A solvent- and self-template design of hierarchical porous carbons is reported.•Carbon source acts as a self-template for ultramicropore (0.54 nm) and supermicropore (0.86, 1.3 nm).•The mesopore (3.6 nm) originates from the HAc-assisted solvent template effect.•The carbon electrode shows high capacitance, excellent rate capability and cycle stability.We design a novel solvent- and self-template strategy to fabricate carbon materials with ultramicro-, supermicro- and mesopores through a simple solvothermal reaction of phloroglucinol and terephthaldehyde in dioxane using acetic acid as the catalyst, followed by carbonization. Dioxane serves simultaneously as a solvent in the reaction system and a template to generate mesopores (3.6 nm). Meanwhile, phloroglucinol/terephthaldehyde polymeric organic frameworks act as a self-template to produce regular and well-developed ultramicropores (0.54 nm) and some supermicropores (0.86 and 1.3 nm) during carbonization. High specific surface area (1003 m2 g−1) coupled with hierarchical porous structure endow the resultant carbon electrode excellent electrochemical properties including a satisfactory specific capacitance (214 F g−1 at 1.0 A g−1), excellent rate capability (154 F g−1 at a very high current density of 50 A g−1) as well as superb long-term cycling stability (95.5% retention of initial capacitance after 10000 cycles) in alkaline electrolyte. Compared with traditional synthetic strategy for porous carbons, the present approach can be easily carried out, avoiding tedious procedure, customized hard/soft template or extra activation step, and thus highlights new opportunities towards the simple and highly efficient synthesis of well-designed porous carbons for supercapacitor applications.Download high-res image (210KB)Download full-size image
Co-reporter:Wenjing Lu, Mingxian Liu, Ling Miao, Dazhang Zhu, Xin Wang, Hui Duan, Zhiwei Wang, Liangchun Li, Zijie Xu, Lihua Gan, Longwu Chen
Electrochimica Acta 2016 Volume 205() pp:132-141
Publication Date(Web):1 July 2016
DOI:10.1016/j.electacta.2016.04.114
•Nitrogen-containing ultramicroporous carbon nanospheres (N-UCNs) are fabricated.•Hexamethylenetetramine is used as both a catalyst and nitrogen source to prepare N-UCNs.•Introduction of phloroglucinol/terephthalaldehyde endows ultramicropores for N-UCNs.•N-UCN electrode exhibits a high specific capacitance and excellent cycle stability.In this paper, we report a facile and novel synthesis of nitrogen-containing ultramicroporous carbon nanospheres (N-UCNs) for high performance supercapacitor electrodes. Phloroglucinol and terephthalaldehyde are polymerized to obtain polymer nanoparticles with a mean diameter of ∼15 nm. Hexamethylenetetramine (HMTA) is utilized to substitute ammonia and formaldehyde to polymerize with resorcinol on the surfaces of the polymer colloids for the fabrication of carbon spheres under the Stöber condition. The introduction of phloroglucinol/terephthalaldehyde brings regular ultramicroporous (0.58 nm) to the typical N-UCNs. Besides, the polymerization of resorcinol and HMTA on the surfaces of polymer nanoparticles reduces the diameter of carbon nanospheres from submicrometer sizes to nanoscaled sizes (∼36 nm). Furthermore, the NH4+ released from the hydrolysis of HMTA also acts a source of nitrogen in the carbon framework (1.21 at.%), which can improve the surface properties and electric conductivity of N-UCNs. The typical N-UCNs (N-UCN4.50) with spherical geometry, high surface area (1439 m2 g−1), regular ultramicropores and nitrogen functional groups shows excellent electrochemical performance such as high specific capacitance (269 F g−1 at 1.0 A g−1), long-term cycle stability (90.3% retention after 10000 charge/discharge cycles) in 6 M KOH aqueous electrolyte. This finding provides new opportunities for well-designed carbon nanospheres to achieve advanced supercapacitor electrodes.
Co-reporter:Ming-Xian Liu, Xiang-Xiang Deng, Da-Zhang Zhu, Hui Duan, Wei Xiong, Zi-Jie Xu, Li-Hua Gan
Chinese Chemical Letters 2016 Volume 27(Issue 5) pp:795-800
Publication Date(Web):May 2016
DOI:10.1016/j.cclet.2016.01.038
Magnetically separated and N, S co-doped mesoporous carbon microspheres (N/S-MCMs/Fe3O4) are fabricated by encapsulating SiO2 nanoparticles within N, S-containing polymer microspheres which were prepared using resorcinol/formaldehyde as the carbon source and cysteine as the nitrogen and sulfur co-precursors, followed by the carbonization process, silica template removal, and the introduction of Fe3O4 into the carbon mesopores. N/S-MCMs/Fe3O4 exhibits an enhanced Hg2+ adsorption capacity of 74.5 mg/g, and the adsorbent can be conveniently and rapidly separated from wastewater using an external magnetic field. This study opens up new opportunities to synthesize well-developed, carbon-based materials as an adsorbent for potential applications in the removal of mercury ions from wastewater.Magnetically separated and N, S co-doped mesoporous carbon microspheres (N/S-MCMs/Fe3O4) was fabricated as an adsorbent for potential applications in the removal of mercury ions from wastewater.
Co-reporter:Ming-Xian Liu, Ling-Yan Chen, Da-Zhang Zhu, Hui Duan, Wei Xiong, Zi-Jie Xu, Li-Hua Gan, Long-Wu Chen
Chinese Chemical Letters 2016 Volume 27(Issue 3) pp:399-404
Publication Date(Web):March 2016
DOI:10.1016/j.cclet.2015.12.026
A novel zinc tartrate oriented hydrothermal synthesis of microporous carbons was reported. Zinc–organic complex obtained via a simple chelation reaction of zinc ions and tartaric acid is introduced into the networks of resorcinol/formaldehyde polymer under hydrothermal condition. After carbonization process, the resultant microporous carbons achieve high surface area (up to 1255 m2/g) and large mean pore size (1.99 nm) which guarantee both high specific capacitance (225 F/g at 1.0 A/g) and fast charge/discharge operation (20 A/g) when used as a supercapacitor electrode. Besides, the carbon electrode shows good cycling stability, with ∼93% capacitance retention at 1.0 A/g after 1000 cycles. The well-designed and high-performance microporous carbons provide important prospects for supercapacitor applications.A novel zinc tartrate oriented hydrothermal synthesis of microporous carbons was demonstrated. The carbons achieve high surface area and large mean pore size which guarantee both high specific capacitance and fast charge/discharge operation in supercapacitor application.
Co-reporter:Mingxian Liu, Jiasheng Qian, Yunhui Zhao, Dazhang Zhu, Lihua Gan and Longwu Chen
Journal of Materials Chemistry A 2015 vol. 3(Issue 21) pp:11517-11526
Publication Date(Web):20 Apr 2015
DOI:10.1039/C5TA02224J
In this paper, we report a novel design and synthesis of core–shell ultramicroporous@microporous carbon nanospheres (UMCNs) for advanced supercapacitor electrodes. Polymer colloids (10–14 nm) are obtained by time-controlled polymerization of phloroglucinol and terephthalaldehyde (P/T). UMCNs with ultramicropores in the inner core and abundant micropores in the outer shell are fabricated by the copolymerization of resorcinol and formaldehyde (R/F) on the surfaces of P/T colloids with the presence of ammonia, followed by carbonization and further KOH activation. The as-prepared UMCNs have an adjustable diameter (52–74 nm) and a high specific surface area (up to 2156 m2 g−1). Inter-particle mesoporosity among UMCNs creates ion buffer reservoirs and reduces the ion diffusion distance, while micropores offer highly efficient ion channels and also show high capability for charge accumulation. Moreover, regular ultramicropores benefit the fast transportation and diffusion of electrolyte ions. Consequently, UMCNs with a unique 3D core–shell nanostructure exhibit superb electrochemical performance such as very high specific capacitance (411 F g−1 at 1 A g−1), ultra-high rate capability (charge–discharge operation under an extremely high current density of 100 A g−1), excellent long-term cycle stability (10000 cycles) and reasonable energy density at high power density (5.94 W h kg−1 at 50 kW kg−1) in a 6 M KOH electrolyte. This finding opens up a new window for well-developed carbon nanoarchitectures to support advanced supercapacitor devices for high rate electrochemical energy storage.
Co-reporter:Yunhui Zhao, Mingxian Liu, Xiangxiang Deng, Ling Miao, Pranav K. Tripathi, Xiaomei Ma, Dazhang Zhu, Zijie Xu, Zhixian Hao, Lihua Gan
Electrochimica Acta 2015 Volume 153() pp:448-455
Publication Date(Web):20 January 2015
DOI:10.1016/j.electacta.2014.11.173
Nitrogen-functionalized microporous carbon nanoparticles (N-MCNs) are prepared by direct carbonization of a novel polymer obtained from the Schiff base reaction of terephthalaldehyde and m-phenylenediamine. The carbonization temperature plays a crucial role in the porosity, surface chemistry and capacitive performance for the carbons. N-MCN850 sample shows a much larger specific surface area of 1938 m2 g−1, a higher specific capacitance of 397 F g−1 and 145 F g−1 at the current density of 0.1 and 100 A g−1 in 6 M KOH aqueous electrolyte, respectively. The results indicate its outstanding capacitive behavior and ultrahigh-rate performance. In addition, the electrode shows excellent cycling stability along with 98% of the initial specific capacitance after 5000 charge/discharge cycles.
Co-reporter:Mingxian Liu, Lihua Gan, Wei Xiong, Zijie Xu, Dazhang Zhu and Longwu Chen
Journal of Materials Chemistry A 2014 vol. 2(Issue 8) pp:2555-2562
Publication Date(Web):03 Dec 2013
DOI:10.1039/C3TA14445C
We report the development of MnO2/porous carbon microspheres with a partially graphitic structure for high performance supercapacitor electrode materials. Micro- and mesoporous carbon microspheres were fabricated based on a hydrothermal emulsion polymerization and common activation process. Manganese nitrate was introduced into the pores of the carbon microspheres, followed by thermal treatment to transform it into amorphous MnO2. As-prepared MnO2/porous carbon microspheres with high specific surface area (up to 1135 m2 g−1) and regular geometry (0.5–1.0 μm in diameter) benefit fast ion-transport and rapid charge–discharge, and contribute double layer capacitance to the hybrid electrode. Besides, manganese dioxide shows high pseudocapacitive behaviour due to faradaic redox reaction. Furthermore, the introduction of MnO2 greatly promotes the graphitization degree of the carbon matrix. A typical MnO2/carbon sample shows a partially graphitic structure with a very low intensity ratio of Raman D to G band (ID/IG = 0.27), which substantially increases the electronic conductivity and reduces the internal resistance (decreased from 0.42 to 0.20 Ω). As a result, the MnO2/porous carbon microspheres as supercapacitor electrodes exhibit excellent electrochemical performance (459 F g−1 at 1.0 A g−1 and 354 F g−1 at 20.0 A g−1 in 6 M KOH electrolyte). The well-developed MnO2/carbon hybrid materials with a high charge–discharge rate capability coupled with a high electrochemical capacitance highlight the great potential for widespread supercapacitor applications.
Co-reporter:Mingxian Liu, Xiaomei Ma, Lihua Gan, Zijie Xu, Dazhang Zhu and Longwu Chen
Journal of Materials Chemistry A 2014 vol. 2(Issue 40) pp:17107-17114
Publication Date(Web):22 Aug 2014
DOI:10.1039/C4TA02888K
Tremendous volume expansion of germanium during cycling causes much difficulty to its use in high performance anodes for lithium ion batteries (LIBs). In this paper, we report a facile synthesis of novel mesoporous Ge@C spheres as stable and high capacity LIB anodes. A Ge–catechol complex obtained via a simple chelation reaction was introduced into resorcinol–formaldehyde polymer spheres prepared by the extended Stöber method. After carbonization and carbothermic reduction at 800 °C in an Ar atmosphere, carbon spheres loaded with Ge nanoparticles (∼8 nm) were fabricated. The Ge@C spheres have a uniform diameter of ∼500 nm, a mesopore size of ∼14 nm and a specific surface area of 348 m2 g−1. Mesoporosity between Ge particles and the carbon matrix creates a buffer layer that effectively stabilizes the encapsulated Ge particles for huge volume change and mitigates the aggregation of active particles during the lithiation/delithiation process. The mesoporous Ge@C sphere anode shows initial discharge and charge specific capacities of 1653 and 1440 mA h g−1 at 0.1 C. Even at a high rate of 10 C, the Ge@C electrode still has a reasonable discharge–charge specific capacity of 753/708 mA h g−1, exhibiting excellent high-rate discharge–charge performance. The Ge@C anode maintains a high discharge capacity of 1099 mA h g−1 at 0.1 C with a coulombic efficiency of 99% after 100 cycles. The simple method for the design of mesoporous Ge@C spheres with a high capacity coupled with an excellent cycling stability opens up a new opportunity of Ge-based anode materials for widespread applications in LIBs.
Co-reporter:Pranav K. Tripathi, Mingxian Liu, Yunhui Zhao, Xiaomei Ma, Lihua Gan, Owen Noonan and Chengzhong Yu
Journal of Materials Chemistry A 2014 vol. 2(Issue 22) pp:8534-8544
Publication Date(Web):31 Mar 2014
DOI:10.1039/C4TA00578C
In this work we prepared hierarchically ordered micro–mesoporous carbon with enlarged uniform micropores, specifically tailored for the high level adsorption of environmental pollutant bisphenol A (BPA). Sizes of both the primary micropore (1.3 nm) and the primary mesopore (9.0 nm) could be tuned by controlling the condensation behavior of phloroglucinol–terephthalaldehyde resin in a tri-constituent system based on evaporation induced self-assembly. As a result of this the special structure was able to develop high surface area (623–1985 m2 g−1) and large pore volume (0.7–2.3 cm3 g−1). By tuning the micropore size to accommodate the molecular dimensions of BPA, an ultra-high adsorption capacity of 1106 mg g−1 was achieved, three times higher than previously reported values. Kinetic studies revealed that high pore interconnectivity and micropore accessibility were the key to unrestricted adsorbate diffusion through the pore channels and the subsequent high level adsorption. This development sheds new light on the importance of the carbon source in the control of pore size in carbons. The materials hold great potential for application in the purification of industrial process water with high level BPA contamination.
Co-reporter:Xiaomei Ma, Lihua Gan, Mingxian Liu, Pranav K. Tripathi, Yunhui Zhao, Zijie Xu, Dazhang Zhu and Longwu Chen
Journal of Materials Chemistry A 2014 vol. 2(Issue 22) pp:8407-8415
Publication Date(Web):26 Mar 2014
DOI:10.1039/C4TA00333K
In this paper, size controllable SiO2 nanoparticles synthesized by adjusting the hydrolysis–condensation time and the concentration of tetraethyl orthosilicate (TEOS) in ethanol–water solution in the presence of ammonia as a catalyst were encapsulated within resorcinol–formaldehyde polymer microspheres which were fabricated in the same ethanol–water–ammonia system. After carbonization and following etching with NaOH solution, a series of mesoporous carbon microspheres (MCMs) with an average diameter of 500 nm, a mesopore size of 3.2–14 nm and surface areas of 659–872 m2 g−1 are obtained. As electrode materials for supercapacitors, typical samples of MCMs with a mesopore size of 3.2 nm and 13.5 nm show an initial specific capacitance of 289 and 268 F g−1 under a current density of 1.0 A g−1. After 10000 charge–discharge cycles, the specific capacity remains 261 and 254 F g−1 with the retention of 90.3% and 94.7%. Besides, electrochemical performances influenced by the mesopore size were investigated.
Co-reporter:Xiaomei Ma, Mingxian Liu, Lihua Gan, Pranav K. Tripathi, Yunhui Zhao, Dazhang Zhu, Zijie Xu and Longwu Chen
Physical Chemistry Chemical Physics 2014 vol. 16(Issue 9) pp:4135-4142
Publication Date(Web):13 Dec 2013
DOI:10.1039/C3CP54507E
In this paper, we demonstrate the design and synthesis of novel mesoporous Si@C microspheres as anode materials for high-performance lithium-ion batteries. SiO2 nanoparticles modified with hexadecyl trimethyl ammonium bromide are enveloped within resorcinol–formaldehyde polymer microspheres which form in the ethanol–water–ammonia system. Mesoporous voids between Si nanoparticles and the carbon framework are generated after carbonization at 800 °C and magnesiothermic reduction at 650 °C. The resultant Si@C microspheres show regular spherical shapes with a mean diameter of about 500 nm, a mesopore size of 3.2 nm and specific surface areas of 401–424 m2 g−1. Mesoporosity of Si@C microspheres effectively buffers the volume expansion/shrinkage of Si nanoparticles during Li ion insertion/extraction, which endows mesoporous Si@C microspheres with excellent electrochemical performance and cycle stability when they are used as lithium-ion battery anode materials. A typical sample of mesoporous Si@C microspheres presents a specific capacity of 1637 and 1375 mA h g−1 at first discharge and charge under a current density of 50 mA g−1. After 100 cycles, the charge capacity remains 1053 mA h g−1 with a coulombic efficiency of 99%, showing good cycle stability of the anode. This finding highlights the potential application of mesoporous Si@C microspheres in lithium-ion battery anode materials.
Co-reporter:Yaokang Lv, Jun Cheng, Peter D. Matthews, Juan Pedro Holgado, Janina Willkomm, Michal Leskes, Alexander Steiner, Dieter Fenske, Timothy C. King, Paul T. Wood, Lihua Gan, Richard M. Lambert and Dominic S. Wright
Dalton Transactions 2014 vol. 43(Issue 23) pp:8679-8689
Publication Date(Web):15 Apr 2014
DOI:10.1039/C4DT00555D
To what extent the presence of transition metal ions can affect the optical properties of structurally well-defined, metal-doped polyoxotitanium (POT) cages is a key question in respect to how closely these species model technologically important metal-doped TiO2. This also has direct implications to the potential applications of these organically-soluble inorganic cages as photocatalytic redox systems in chemical transformations. Measurement of the band gaps of the series of closely related polyoxotitanium cages [MnTi14(OEt)28O14(OH)2] (1), [FeTi14(OEt)28O14(OH)2] (2) and [GaTi14(OEt)28O15(OH)] (3), containing interstitial Mn(II), Fe(II) and Ga(III) dopant ions, shows that transition metal doping alone does not lower the band gaps below that of TiO2 or the corresponding metal-doped TiO2. Instead, the band gaps of these cages are within the range of values found previously for transition metal-doped TiO2 nanoparticles. The low band gaps previously reported for 1 and for a recently reported related Mn-doped POT cage appear to be the result of low band gap impurities (most likely amorphous Mn-doped TiO2).
Co-reporter:Yunhui Zhao, Mingxian Liu, Lihua Gan, Xiaomei Ma, Dazhang Zhu, Zijie Xu, and Longwu Chen
Energy & Fuels 2014 Volume 28(Issue 2) pp:1561-1568
Publication Date(Web):December 27, 2013
DOI:10.1021/ef402070j
Novel ultramicroporous carbon nanoparticles (UCNs) are synthesized on the basis of solvothermal polymerization of phloroglucinol and terephthaldehyde in dioxane at 220 °C, followed by carbonization at 850 °C. The resultant UCNs show regular 0.54 nm ultramicropores and particle sizes of ∼30 nm. The UCNs as electrode materials for electrical double-layer capacitors (EDLCs) show a specific capacitance of 206 F g–1 at 1.0 A g–1 in a 6 M KOH aqueous solution. The UCN electrode is suitable for charge–discharge operation even at a very high current density of 50 A g–1 coupled with a capacitance of 135 F g–1, indicating excellent high-rate electrochemical performance. The electrochemical capacitance of the UCN electrode has a high retention of 97.6% after 5000 cycles at 1.0 A g–1 tested by a standard three-electrode system (97.3% for the two-electrode cell), which implies a good electrochemical cycling life. This study highlights promising prospects of novel UCNs as advanced electrode materials for EDLCs where a high level of current charge and discharge is required.
Co-reporter:Pranav K. Tripathi, Mingxian Liu and Lihua Gan
RSC Advances 2014 vol. 4(Issue 45) pp:23853-23860
Publication Date(Web):15 Apr 2014
DOI:10.1039/C4RA01570C
Synthesis of carbon materials with enhanced surface areas, and regular and tuned pore diameters is always a great challenge. In this report, ordered mesoporous carbons (OMCs) were synthesized by the one-step assembly of tri-constituents, and the OMCs were applied as an adsorbent for the removal of the highly hazardous water pollutant di(2-ethylhexyl)phthalate (DEHP). Phloroglucinol–formaldehyde based carbon precursor was in situ prepared during the assembly of the tri-constituents, and the surface area and mesopore diameter of the OMCs were tuned by variation of the molar ratio of formaldehyde to phloroglucinol. Small angle X-ray diffraction patterns revealed that the obtained carbons are highly ordered, which is in agreement with the measuring results of transmission electron microscopy at low and high resolution. Scanning electron microscopy images demonstrate that OMC-F2.0 has a hierarchical morphology. Nitrogen adsorption–desorption measurements revealed that the surface area of the OMCs (956–1801 m2 g−1) was dependent on the molar ratio of the carbon precursor constituents (formaldehyde to phloroglucinol). By varying the molar ratio of formaldehyde to phloroglucinol from 1.0 to 4.0, the mesopore diameter of the OMCs was shifted to the higher side, from 2.1 to 3.1 nm. DEHP was efficiently removed from a model water pollutant by the OMCs. OMC-F2.0 achieved the highest adsorption capacity of 364 mg g−1 for the removal of DEHP. The adsorption equilibrium data were treated with the two mathematical models of Langmuir and Freundlich, and the results revealed that decontamination was more favorable with the Langmuir model. This concludes that the removal of DEHP by OMCs depends on the surface area, and the DEHP molecules occupied the porous space of the OMCs in a monolayer manner.
Co-reporter:Ming-Xian Liu, Li-Hua Gan, Yang Li, Da-Zhang Zhu, Zi-Jie Xu, Long-Wu Chen
Chinese Chemical Letters 2014 Volume 25(Issue 6) pp:897-901
Publication Date(Web):June 2014
DOI:10.1016/j.cclet.2014.01.010
A novel synthesis of hierarchical porous carbons (HPCs) with 3D open-cell structure based on nanosilica-embedded emulsion-templated polymerization was reported. An oil-in-water emulsion containing SiO2 colloids was fabricated using liquid paraffin as an oil phase, resorcinol/formaldehyde and silica sol as an aqueous phase, and Span 80/Tween 80 as emulsifiers. HPCs with macropore cores, open meso/macropore windows, and abundant micropores were synthesized by the polymerization and carbonization of the emulsion, followed by scaffold removal and further KOH activation. A typical HPCs sample as supercapacitor electrode shows the charge/discharge capability under large loading current density (30 A/g) coupling with a reasonable electrochemical capacitance in KOH electrolyte solution.Hierarchical porous carbons (HPCs) with 3D open-cell structure were synthesized based on nanosilica-embedded emulsion-templated polymerization. The HPCs as electrode for supercapacitor shows the charge/discharge capability under large loading current density (30 A/g) coupling with a reasonable electrochemical capacitance.
Co-reporter:Pranav K. Tripathi, Lihua Gan, Mingxian Liu, Xiaomei Ma, Yunhui Zhao, Dazhang Zhu, Zijie Xu, Longwu Chen, Nageswara N. Rao
Materials Letters 2014 120() pp: 108-110
Publication Date(Web):
DOI:10.1016/j.matlet.2014.01.057
Co-reporter:Jiasheng Qian, Mingxian Liu, Lihua Gan, Pranav K. Tripathi, Dazhang Zhu, Zijie Xu, Zhixian Hao, Longwu Chen and Dominic S. Wright
Chemical Communications 2013 vol. 49(Issue 29) pp:3043-3045
Publication Date(Web):27 Feb 2013
DOI:10.1039/C3CC41113C
We established a novel and facile strategy to synthesize uniform polymer and carbon nanospheres, the diameters of which can be precisely programmed between 35–105 and 30–90 nm, respectively, via time-controlled formation of colloidal seeds. The carbon nanospheres show promising prospects in high rate performance electrochemical energy storage.
Co-reporter:Mingxian Liu, Lihua Gan, Wei Xiong, Fengqi Zhao, Xuezhong Fan, Dazhang Zhu, Zijie Xu, Zhixian Hao, and Longwu Chen
Energy & Fuels 2013 Volume 27(Issue 2) pp:1168-1173
Publication Date(Web):January 18, 2013
DOI:10.1021/ef302028j
A novel high-performance electrode material, nickel-doped activated mesoporous carbon microsphere (Ni-AMCM), is synthesized by an emulsion-assisted hydrothermal method, followed by a KOH activation process and nickel-doping strategy. The morphology, microstructure, and graphitization degree of Ni-AMCMs are characterized by scanning electron microscopy, nitrogen adsorption and desorption, X-ray diffraction, and Raman spectroscopy. The results show that, when the mass ratio of nickel precursor/AMCMs is 0.02, the resultant sample [denoted as Ni(0.02)-AMCMs] retains the structure parameters of AMCMs, such as the specific surface area, total pore volume, and mean pore size. The intensity ratio of Raman D to G band (ID/IG) decreases from 0.99 (AMCMs) to 0.75 [Ni(0.02)-AMCMs], indicating the formation of a partial graphite structure in Ni(0.02)-AMCMs. The Ni-AMCMs combine the features of high specific surface area (∼1096 m2 g–1), uniform mesopore size (4.0 nm), regular microspherical shape (0.5–1.0 μm in diameter), and partially graphitic structure, which endows them good electrochemical performance. The internal resistance of Ni(0.02)-AMCMs is 0.24 Ω, 43% lower than that of AMCMs (0.42 Ω). Correspondingly, Ni(0.02)-AMCM as an electrode in 6 M KOH shows a specific capacitance of 361 F g–1 at 1.0 A g–1. It still maintains an electrochemical capacitance of 301 F g–1 under a high current density of 20.0 A g–1. This finding is potentially important for supercapacitor applications, where a fast charge/discharge is required.
Co-reporter:Ming-Xian Liu, Li-Hua Gan, Wei Xiong, Da-Zhang Zhu, Zi-Jie Xu, Long-Wu Chen
Chinese Chemical Letters 2013 Volume 24(Issue 12) pp:1037-1040
Publication Date(Web):December 2013
DOI:10.1016/j.cclet.2013.07.013
Partially graphitic micro- and mesoporous carbon microspheres (GMMCMs) were synthesized using hydrothermal emulsion polymerization followed by KOH activation and catalytic graphitization. The resulting GMMCMs show micro- and mesopores with a specific surface area of 1113 m2/g, regular spherical shape with diameters of 0.5–1.0 μm and a partially graphitic structure with a low internal resistance of 0.34 Ω. The graphitic carbons as electrode for supercapacitor exhibit a fast ion-transport and rapid charge–discharge feature, and a high-rate electrochemical performance. The typical GMMCM electrode shows a specific capacitance of 220 F/g at 1.0 A/g, and 185 F/g under a high current density of 20.0 A/g in a 6 mol/L KOH electrolyte.Partially graphitic micro- and mesoporous carbon microspheres with high specific surface area and low internal resistance were synthesized based on hydrothermal emulsion polymerization, KOH activation and catalytic graphitization. The carbon electrode exhibits fast ion-transport and rapid charge–discharge features, and high-rate electrochemical performance.
Co-reporter:Mingming Yao, Mingxian Liu, Lihua Gan, Fengqi Zhao, Xuezhong Fan, Dazhang Zhu, Zijie Xu, Zhixian Hao, Longwu Chen
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2013 Volume 433() pp:132-138
Publication Date(Web):20 September 2013
DOI:10.1016/j.colsurfa.2013.05.020
•Monoclinic mesoporous BiVO4 was prepared by using SiO2 aerogel as a hard template.•Typical BiVO4 had a specific surface area of 20.9 m2 g−1 and a pore size of 18.2 nm.•Monoclinic mesoporous BiVO4 photocatalyst showed a narrow band gap of 2.05 eV.•BiVO4 had excellent photocatalytic degradation for Rhodamine B under visible light.In this paper, we report the synthesis of monoclinic scheelite mesoporous bismuth vanadate by an impregnated-template method. Bismuth nitrate pentahydrate and ammonia metavanadate were respectively used as bismuth and vanadium precursors, and mesoporous SiO2 aerogel was used as a hard template. Monoclinic-phase mesoporous BiVO4 was obtained by heat treatment of the precursor/template, followed by NaOH solution etching to remove SiO2 template. The resultant BiVO4 samples were characterized by X-ray diffraction, N2 adsorption and desorption, UV–vis diffuse reflectance spectra, UV–vis spectroscopy, Raman spectroscopy, and transmission electron microscopy. The results indicate that typical BiVO4 sample has pure monoclinic-phase mesoporous structure and possesses a specific surface area of 20.9 m2 g−1 with a pore size of 18.2 nm. The band gap of such mesoporous BiVO4 was estimated to be 2.05 eV, making them excellent photocatalytic activities under visible light. The photocatalytic efficiency of the monoclinic mesoporous BiVO4 for the degradation of Rhodamine B under the visible light illumination (λ > 400 nm) in 120 min reaches 99%, Besides, the mesoporous BiVO4 photocatalyst still showed high stability: 97% for Rhodamine B degradation after four recycles.Graphical abstractMonoclinic mesoporous BiVO4 was prepared by using silica aerogel as a hard template. Typical BiVO4 had a specific surface area of 20.9 m2 g−1 with a pore size of 18.2 nm and narrow band gap (Eg = 2.05 eV). Monoclinic mesoporous BiVO4 showed 99% degradation for Rhodamine B under visible light in 120 min and maintained up to 97% degradation efficiency after four recycles.
Co-reporter:Yaokang Lv, Lihua Gan, Mingxian Liu, Wei Xiong, Zijie Xu, Dazhang Zhu, Dominic S. Wright
Journal of Power Sources 2012 Volume 209() pp:152-157
Publication Date(Web):1 July 2012
DOI:10.1016/j.jpowsour.2012.02.089
Hierarchical porous carbon foams (denoted as HPCFs) is prepared through a novel self-template strategy based on banana peel. Banana peel, which contains natural porous structure formed by biopolymers in cell walls, can absorb ions and phenolic compounds. The carboxylic and hydroxyl groups on the pores’ surface will coordinate with zinc ions to form zinc complexes. These zinc complexes which are similar with metal–organic frameworks are used as self-template, and the aminophenol furfural resin polymerized in the pores of complexes is used as the additional carbon source to create hierarchical porous structure during the carbonization process. The resulted HPCFs are composed of macroporous cores with mesoporous and microporous channels. The unique self-supported hierarchical structure possesses a high specific surface area (1650 m2 g−1) and provides a more favorable path for electrolyte penetration and transportation, which give rise to the excellent electrochemical property of HPCFs as an electrode material for supercapacitor. The calculated specific capacitance of HPCFs electrode in 6 mol L−1 KOH is 206 F g−1 at a current density of 1 A g−1, while the specific capacitance still exhibits relative high (182 F g−1) at a higher current density of 10 A g−1 with the retention of 88%.Graphical abstractHighlights► We report a self-template synthesis of hierarchical porous carbon foams (HPCFs). ► Banana peel based zinc complex was employed as the self-template to prepare HPCFs. ► HPCFs is composed of macroporous cores with mesoporous and microporous channels. ► HPCFs possesses a high specific surface area and self-supported architecture. ► HPCFs exhibits excellent electrochemical properties as an electrode material.
Co-reporter:Yao-Kang Lv, Yun-Long Feng, Li-Hua Gan, Ming-Xian Liu, Liang Xu, Cao Liu, Hao-Wen Zheng, Jie Li
Journal of Solid State Chemistry 2012 Volume 185() pp:198-205
Publication Date(Web):January 2012
DOI:10.1016/j.jssc.2011.11.010
A novel trinuclear cobalt-oxo cluster 2[Co3O(Ac)6(H2O)3]·H2O (Co-OXO) has been obtained and characterized by X-ray single-crystal diffraction and elemental analysis. The structure of Co-OXO displays 3D supramolecular networks through hydrogen bonds and generates boron nitride (bnn) topology. Co-OXO was further used as a precursor to synthesize Co-containing mesoporous carbon foams (Co-MCFs), which exhibit highly ordered mesostructure with specific surface area of 614 m2 g−1 and uniform pore size of 2.7 nm. Charge–discharge tests show that the specific discharge capacitance of Co-MCFs is 7% higher than that of the MCFs at the current density of 100 mA g−1, and 26% higher than that of MCFs at the current density of 3 A g−1. The electrochemical behaviors of Co-MCFs are obviously improved due to the improved wettability, increased graphitization degree and the pseudo-capacitance through additional faradic reactions arising from cobalt.Graphical AbstractA new trinuclear cobalt-oxo cluster, 2[Co3O(Ac)6(H2O)3]·H2O (1), was obtained and further used as a precursor to synthesize Co-containing mesoporous carbon foams (Co-MCFs) which exhibit improved electrochemical behaviors.Highlights► A new trinuclear cobalt-oxo cluster (1) were obtained. ► 1 is joined by hydrogen bonds to construct a 3D structure showing bnn topology. ► 1 was further used to obtain Co-containing mesoporous carbon foams (Co-MCFs). ► Co-MCFs exhibit highly ordered mesostructure and uniform pore sizes. ► Electrochemical behaviors of Co-MCFs are obviously improved compared with pure MCFs.
Co-reporter:Mingxian Liu, Lihua Gan, Liuhua Chen, Zijie Xu, Dazhang Zhu, Zhixian Hao, and Longwu Chen
Langmuir 2012 Volume 28(Issue 29) pp:10725-10732
Publication Date(Web):June 29, 2012
DOI:10.1021/la3021645
The fabrication of core–shell structural nanosilica@liposome nanocapsules as a drug delivery vehicle is reported. SiO2 nanoparticles are encapsulated within liposomes by a W/O/W emulsion approach to form supramolecular assemblies with a core of colloidal particles enveloped by a lipid bilayer shell. A nanosilica core provides charge compensation and architectural support for the lipid bilayer, which significantly improves their physical stability. A preliminary application of these core–shell nanocapsules for hemoglobin (Hb) delivery is described. Through the H-bonding interaction between the hydroxyl groups on nanosilicas and the amino nitrogens of Hb, Hb–SiO2 nanocomplexes in which the saturated adsorption amount of Hb on SiO2 is 0.47 g g–1 are coated with lipids to generate core–shell Hb–SiO2@liposome nanocapsules with mean diameters of 60–500 nm and Hb encapsulation efficiency of 48.4–87.9%. Hb–SiO2@liposome supramolecular nanovehicles create a mode of delivery that stabilizes the encapsulated Hb and achieves long-lasting release, thereby improving the efficacy of the drug. Compared with liposome-encapsulated Hb and Hb-loaded SiO2 particles, such core–shell nanovehicles show substantially enhanced release performance of Hb in vitro. This finding opens up a new window of liposome-based formulations as drug delivery nanovehicles for widespread pharmaceutical applications.
Co-reporter:Mingxian Liu, Liuhua Chen, Yunhui Zhao, Lihua Gan, Dazhang Zhu, Wei Xiong, Yaokang Lv, Zijie Xu, Zhixian Hao, Longwu Chen.
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2012 Volume 395() pp:131-136
Publication Date(Web):5 February 2012
DOI:10.1016/j.colsurfa.2011.12.017
We reported the preparation and properties of liposome-loaded polycaprolactone microspheres (LPMs) as a drug delivery system for controlling the release of flurbiprofen. LPMs were fabricated using double emulsion solvent extraction/evaporation method and characterized by scanning electron microscopy, Fourier transform infrared spectrum, X-ray diffraction, differential scanning calorimeter and UV–vis spectrum. The results suggest that LPMs have uniform sizes with pores on the external surface. Liposomes are intactly encapsulated in LPMs, which causes slight change of polycaprolactone from semi-crystalline to less-ordered amorphous. The concentrations of polycaprolactone and polyvinyl alcohol (PVA) and the amount of liposomes can affect the diameter, surface morphology and encapsulation efficiency of LPMs. The diameter of LPMs increases from 80 to 200 μm and the encapsulation efficiency of flurbiprofen in LPMs increases from 36.92% to 48.42% when the concentration of polycaprolactone increases from 0.15 to 0.6 g/mL. However, the larger amount of liposomes promotes the aggregation between emulsion droplets and causes more pores on the surface of LPMs, which leads to lower drug encapsulation efficiency. The presence of PVA stabilizes the emulsion droplets against coalescence. With the increase of PVA concentration, the diameter of LPMs decreases and the amount of flurbiprofen encapsulated in LPMs increases. In vitro release studies suggest the structure and morphology of LPMs have close relationship with drug release kinetics. The smaller LPMs with more porous surface have faster cumulative release rate.Graphical abstractBy using a w/o/w double emulsion solvent extraction/evaporation method, liposome-loaded polycaprolactone microspheres were prepared as a drug delivery system for the controlled release of flurbiprofen.Highlights► LPMs were fabricated by using a double emulsion solvent extraction/evaporation method. ► Flurbiprofen liposomes can keep intact inside the microspheres after encapsulation. ► The smaller LPMs with more porous surface have faster cumulative release rate.
Co-reporter:Wei Xiong, Mingxian Liu, Lihua Gan, Yaokang Lv, Zijie Xu, Zhixian Hao, Longwu Chen
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2012 Volume 411() pp:34-39
Publication Date(Web):5 October 2012
DOI:10.1016/j.colsurfa.2012.06.042
An oil-in-water (O/W) emulsion system of Span 80–Tween 80/1iquid paraffin/aqueous resorcinol–formaldehyde was manufactured. Nitrogen-doped macro-/mesoporous carbon foams (N-MMCFs) were prepared by the polymerization of this O/W emulsion, followed by carbonization and activation process. As-prepared N-MMCFs were characterized by scanning electron microscopy, infrared (IR) spectra, N2 adsorption and desorption analysis, and electrochemical workstation. The results indicate that the N-MMCFs have main macropore of 0.2 μm, mesopore of 2.6–4.0 nm and specific surface areas of 1205–1808 m2 g−1. The contact angle of N-MMCFs for water is about 37.5°, obviously lower than that of MMCFs (72.9°), which suggests that the surface wettability of N-MMCFs is greatly improved due to the incorporation of nitrogen into the carbon framework. Electrochemical measurements show that specific capacitance of a typical N-MMCF as electrode material in 6 M KOH aqueous solution is as high as 198 F g−1 at a current density of 1.0 A g−1. Its specific capacitance can still remain 159 F g−1 at a high loading current density of 20.0 A g−1 with the retention of 80.3%, which indicates that the typical N-MMCF as electrode material has a good rate capability. The high current charge and discharge capability offers the promising prospects for the application of N-MMCFs as electrode materials in supercapacitors which could meet the need of high power density.Graphical abstractNitrogen-doped macro-/mesoporous carbon foams (N-MMCFs) with main macropore of 0.2 μm, mesopore of 2.6–4.0 nm and specific surface areas of 1205–1808 m2 g−1 were prepared by employing oil-in-water emulsion polymerization and activated method. The typical N-MMCFs have a specific capacitance of 159 F g−1 at a very high current density of 20.0 A g−1.Highlights► N-MMCFs with dual-sized pore structures were prepared by emulsion-activated method. ► The typical N-MMCF-3 exhibits large specific capacitance at high current density. ► The N-MMCFs sample is an excellent material for use in supercapacitors.
Co-reporter:Wei Xiong, Mingxian Liu, Lihua Gan, Yaokang Lv, Yang Li, Liang Yang, Zijie Xu, Zhixian Hao, Honglai Liu, Longwu Chen
Journal of Power Sources 2011 Volume 196(Issue 23) pp:10461-10464
Publication Date(Web):1 December 2011
DOI:10.1016/j.jpowsour.2011.07.083
Mesoporous carbon microspheres (MCMs) with the diameters of 0.5–2.0 μm, main mesopore sizes of 2.6–4.0 nm and specific surface areas of 449–1212 m2 g−1 are synthesized by a novel hydrothermal emulsion-activated method. The typical MCMs as electrode materials have a specific capacitance of 157 F g−1 at a high current density of 10.0 A g−1 in 6 M KOH aqueous solution. The resultant MCMs electrode materials with high current charge and discharge capability in 6 M KOH aqueous solution provide important prospect for electrode materials in supercapacitors which could offer high power density for electric vehicles.Graphical abstractMesoporous carbon microspheres (MCMs) with the diameters of 0.5–2.0 μm and mean mesopore sizes of 2.6–4.0 nm were synthesized by a novel hydrothermal emulsion-activated method. The typical MCMs electrode materials have a specific capacitance of 157 F g−1 in 6 M KOH aqueous solution at a high current density of 10.0 A g−1.Highlights► Mesoporous carbon microspheres (MCMs) were synthesized by a novel hydrothermal emulsion-activated method. ► The typical MCMs electrode have a specific capacitance of 157 F g−1 in 6 M KOH aqueous solution at a high current density of 10.0 A g−1. ► The resultant MCMs electrode materials with high current charge and discharge capability provide important prospect for electrode materials in supercapacitors.
Co-reporter:Rong Fan, Lihua Gan, Mingxian Liu, Dazhang Zhu, Liuhua Chen, Zijie Xu, Zhixian Hao, Longwu Chen
Applied Surface Science 2011 Volume 257(Issue 6) pp:2102-2106
Publication Date(Web):1 January 2011
DOI:10.1016/j.apsusc.2010.09.057
Abstract
An interaction of helicid with phosphatidylcholine liposome biomembrane was studied by transmission electron microscopy, UV–vis, fluorescence, Raman and 31P NMR spectra. The results indicate that most of helicid molecules associate with liposomes at their surface and some of them penetrate the liposomes and locate in the hydrophobic regions of the membrane. The distribution coefficient KD between liposome phases and aqueous phases is 13.5. The liposome becomes more dispersive and stable in the presence of helicid. The microenvironmental micropolarity and the microhydrophobicity of liposome membrane decrease with the increase of helicid concentration. The interaction of helicid molecules with liposome results in a slight decrease of the membrane longitudinal order, and an increase of the membrane lateral order. A model for the interaction of helicid with liposome biomembrane is proposed on the basis of the change of microenvironment parameters of liposome including the micropolarity, microhydrophobicity and membrane order. The change of microenvironment parameters results mainly from hydrogen bonding interaction between the hydroxyl groups of the pyranoside rings of helicid molecules and the polar head groups of phosphatidylcholine.
Co-reporter:Liuhua Chen, Lihua Gan, Mingxian Liu, Rong Fan, Zijie Xu, Zhixian Hao, Longwu Chen
Applied Surface Science 2011 Volume 257(Issue 11) pp:5070-5076
Publication Date(Web):15 March 2011
DOI:10.1016/j.apsusc.2011.01.023
Abstract
The effect of tryptophan on the membrane stability was studied by using three artificial biological membranes including liposome, Langmuir monolayer and solid supported bilayer lipid membrane (s-BLM) as models. All the results indicate that the penetration of tryptophan can destabilize different artificial biological membranes. The diameter of liposome and the leakage of calcein from liposome increased with the increase of tryptophan concentration because the penetration of tryptophan was beneficial for dehydrating the polar head groups of lipids and the formation of fusion intermediates. π-A isotherms of lecithin on the subphase of tryptophan solution further confirm that tryptophan can penetrate into lipid monolayer and reduce the stability of lipid monolayer. When the concentration of tryptophan increased from 0 to 2 × 10−3 mol L−1, the limiting molecular area of lecithin increased from 110.5 to 138.5 Å2, but the collapse pressure of the monolayer decreased from 47.6 to 42.3 mN m−1, indicating the destabilization of lipid monolayer caused by the penetration of tryptophan. The resistance spectra of s-BLM demonstrate that the existence of tryptophan leads to the formation of some defects in s-BLM and the destabilization of s-BLM. The values of electron-transfer resistance and double layer capacitance respectively decreased from 5.765 × 106 Ω and 3.573 × 10−8 F to 1.391 × 106 Ω and 3.340 × 10−8 F when the concentration of tryptophan increased from 0 to 2 × 10−3 mol L−1. Correspondingly, the breakdown voltage of s-BLM decreased from 2.51 to 1.72 V.
Co-reporter:Liuhua Chen;Lihua Gan;Shenjing An;Dazhang Zhu;Zijie Xu;Zhixian Hao ;Longwu Chen
Chinese Journal of Chemistry 2010 Volume 28( Issue 2) pp:193-198
Publication Date(Web):
DOI:10.1002/cjoc.201090053
Abstract
The interaction between (1,1′-binaphthalene)-2,2′-diol (BINOL) and lecithin liposome was studied by UV-Vis, fluorescence and 1H NMR spectroscopies. BINOL can obviously associate with lecithin liposome and the preferential binding site of BINOL with lecithin liposome is located in the headgroup region. The hydrogen bond and electrostatic interaction should exist in BINOL/liposome system, which restricts intra-annular rotation of naphthol moieties. Therefore, the fluorescence intensity of BINOL increases when a small quantity of liposome is added into the system. The partition coefficient KD between the lecithin liposome and the aqueous phase is 310.9. With the increase of BINOL concentration, the micropolarity (I1/I3) and membrane fluidity of liposome decreased, while the viscosity of membrane increased.
Co-reporter:Shu-ping ZHANG, Ming-xian LIU, Li-hua GAN, Fang-rui WU, Zi-jie XU, Zhi-xian HAO, Long-wu CHEN
New Carbon Materials 2010 Volume 25(Issue 1) pp:9-14
Publication Date(Web):February 2010
DOI:10.1016/S1872-5805(09)60012-3
Co-reporter:Ming-Xian LIU;Zhi-Xian HAO;Zi-Jie XU;Da-Zhang ZHU ;Long-Wu CHEN
Chinese Journal of Chemistry 2008 Volume 26( Issue 1) pp:39-43
Publication Date(Web):
DOI:10.1002/cjoc.200890035
Abstract
Negatively charged magnetite nanoparticles with an average size of about 10 nm have been synthesized by a chemical coprecipitation method using sodium dodecyl benzene sulphonate as a surface modifying reagent. Composite Langmuir monolayer of Fe3O4 nanoparticles and geminus surfactant 1,3-propylenebis(dodecyldimethylammonium) dibromide (C12-C3-C12) was prepared on the subphase of Fe3O4 nanoparticle hydrosols. In the presence of the magnetite nanoparticles, the collapse pressure of the composite monolayer and the limited mean molecular area of C12-C3-C12 are higher than those on pure water subphase. Transmission electron microscopy observation of a C12-C3-C12/Fe3O4 nanoparticle complex shows that Fe3O4 nanoparticles and geminus surfactant had an unexpected hexagonal nanoarchitecture at the air-liquid interface when the surface pressure of the composite monolayer increased to about 12 mN·m−1. A mechanism for constructing the particular nanopatterned configuration of the C12-C3-C12/Fe3O4 nanoparticle complex in the Langmuir layer directly from the unique molecular structure of the geminus surfactant and the interfacial interactions between C12-C3-C12 and the components in the subphase was proposed.
Co-reporter:Mingxian Liu, Lihua Gan, Fengqi Zhao, Xuezhong Fan, Huixiang Xu, Fangrui Wu, Zijie Xu, Zhixian Hao, Longwu Chen
Carbon 2007 Volume 45(Issue 15) pp:3055-3057
Publication Date(Web):December 2007
DOI:10.1016/j.carbon.2007.10.003
Co-reporter:Mingxian Liu, Lihua Gan, Fengqi Zhao, Huixiang Xu, Xuezhong Fan, Ci Tian, Xi Wang, Zijie Xu, Zhixian Hao, Longwu Chen
Carbon 2007 Volume 45(Issue 13) pp:2710-2712
Publication Date(Web):November 2007
DOI:10.1016/j.carbon.2007.08.004
Co-reporter:Zijie Xu;Lihua Gan;Yunyan Jia;Zhixian Hao
Journal of Sol-Gel Science and Technology 2007 Volume 41( Issue 3) pp:203-207
Publication Date(Web):2007 March
DOI:10.1007/s10971-006-1500-z
A method to prepare silica-titania aerogel-like balls (STABs) with photocatalytic activity was reported. Silica-titania sol was prepared by mixing self-made titania sol with commercial silica sol. Silica-titania gel balls were prepared by ball-dropping method (BDM) and sol-gel process. The mechanical strength of gel balls is obviously improved by immersing them in TEOS/alcohol solution before the start of gel drying procedure. These strengthened wet gel balls were dried at ambient pressure and STABs with small shrinkage were obtained. Characters of porous structures of STABs were characterized by transmission electron microscope (TEM) and Brunauer-Emmett-Teller (BET) method. STABs also display excellent photocatalytic activity for the degradation of methylene blue as a simulated aqueous organic pollutant in waste water.
Co-reporter:Xiaomei Ma, Lihua Gan, Mingxian Liu, Pranav K. Tripathi, Yunhui Zhao, Zijie Xu, Dazhang Zhu and Longwu Chen
Journal of Materials Chemistry A 2014 - vol. 2(Issue 22) pp:NaN8415-8415
Publication Date(Web):2014/03/26
DOI:10.1039/C4TA00333K
In this paper, size controllable SiO2 nanoparticles synthesized by adjusting the hydrolysis–condensation time and the concentration of tetraethyl orthosilicate (TEOS) in ethanol–water solution in the presence of ammonia as a catalyst were encapsulated within resorcinol–formaldehyde polymer microspheres which were fabricated in the same ethanol–water–ammonia system. After carbonization and following etching with NaOH solution, a series of mesoporous carbon microspheres (MCMs) with an average diameter of 500 nm, a mesopore size of 3.2–14 nm and surface areas of 659–872 m2 g−1 are obtained. As electrode materials for supercapacitors, typical samples of MCMs with a mesopore size of 3.2 nm and 13.5 nm show an initial specific capacitance of 289 and 268 F g−1 under a current density of 1.0 A g−1. After 10000 charge–discharge cycles, the specific capacity remains 261 and 254 F g−1 with the retention of 90.3% and 94.7%. Besides, electrochemical performances influenced by the mesopore size were investigated.
Co-reporter:Yaokang Lv, Jun Cheng, Peter D. Matthews, Juan Pedro Holgado, Janina Willkomm, Michal Leskes, Alexander Steiner, Dieter Fenske, Timothy C. King, Paul T. Wood, Lihua Gan, Richard M. Lambert and Dominic S. Wright
Dalton Transactions 2014 - vol. 43(Issue 23) pp:NaN8689-8689
Publication Date(Web):2014/04/15
DOI:10.1039/C4DT00555D
To what extent the presence of transition metal ions can affect the optical properties of structurally well-defined, metal-doped polyoxotitanium (POT) cages is a key question in respect to how closely these species model technologically important metal-doped TiO2. This also has direct implications to the potential applications of these organically-soluble inorganic cages as photocatalytic redox systems in chemical transformations. Measurement of the band gaps of the series of closely related polyoxotitanium cages [MnTi14(OEt)28O14(OH)2] (1), [FeTi14(OEt)28O14(OH)2] (2) and [GaTi14(OEt)28O15(OH)] (3), containing interstitial Mn(II), Fe(II) and Ga(III) dopant ions, shows that transition metal doping alone does not lower the band gaps below that of TiO2 or the corresponding metal-doped TiO2. Instead, the band gaps of these cages are within the range of values found previously for transition metal-doped TiO2 nanoparticles. The low band gaps previously reported for 1 and for a recently reported related Mn-doped POT cage appear to be the result of low band gap impurities (most likely amorphous Mn-doped TiO2).
Co-reporter:Mingxian Liu, Xiaomei Ma, Lihua Gan, Zijie Xu, Dazhang Zhu and Longwu Chen
Journal of Materials Chemistry A 2014 - vol. 2(Issue 40) pp:NaN17114-17114
Publication Date(Web):2014/08/22
DOI:10.1039/C4TA02888K
Tremendous volume expansion of germanium during cycling causes much difficulty to its use in high performance anodes for lithium ion batteries (LIBs). In this paper, we report a facile synthesis of novel mesoporous Ge@C spheres as stable and high capacity LIB anodes. A Ge–catechol complex obtained via a simple chelation reaction was introduced into resorcinol–formaldehyde polymer spheres prepared by the extended Stöber method. After carbonization and carbothermic reduction at 800 °C in an Ar atmosphere, carbon spheres loaded with Ge nanoparticles (∼8 nm) were fabricated. The Ge@C spheres have a uniform diameter of ∼500 nm, a mesopore size of ∼14 nm and a specific surface area of 348 m2 g−1. Mesoporosity between Ge particles and the carbon matrix creates a buffer layer that effectively stabilizes the encapsulated Ge particles for huge volume change and mitigates the aggregation of active particles during the lithiation/delithiation process. The mesoporous Ge@C sphere anode shows initial discharge and charge specific capacities of 1653 and 1440 mA h g−1 at 0.1 C. Even at a high rate of 10 C, the Ge@C electrode still has a reasonable discharge–charge specific capacity of 753/708 mA h g−1, exhibiting excellent high-rate discharge–charge performance. The Ge@C anode maintains a high discharge capacity of 1099 mA h g−1 at 0.1 C with a coulombic efficiency of 99% after 100 cycles. The simple method for the design of mesoporous Ge@C spheres with a high capacity coupled with an excellent cycling stability opens up a new opportunity of Ge-based anode materials for widespread applications in LIBs.
Co-reporter:Xiaomei Ma, Mingxian Liu, Lihua Gan, Pranav K. Tripathi, Yunhui Zhao, Dazhang Zhu, Zijie Xu and Longwu Chen
Physical Chemistry Chemical Physics 2014 - vol. 16(Issue 9) pp:NaN4142-4142
Publication Date(Web):2013/12/13
DOI:10.1039/C3CP54507E
In this paper, we demonstrate the design and synthesis of novel mesoporous Si@C microspheres as anode materials for high-performance lithium-ion batteries. SiO2 nanoparticles modified with hexadecyl trimethyl ammonium bromide are enveloped within resorcinol–formaldehyde polymer microspheres which form in the ethanol–water–ammonia system. Mesoporous voids between Si nanoparticles and the carbon framework are generated after carbonization at 800 °C and magnesiothermic reduction at 650 °C. The resultant Si@C microspheres show regular spherical shapes with a mean diameter of about 500 nm, a mesopore size of 3.2 nm and specific surface areas of 401–424 m2 g−1. Mesoporosity of Si@C microspheres effectively buffers the volume expansion/shrinkage of Si nanoparticles during Li ion insertion/extraction, which endows mesoporous Si@C microspheres with excellent electrochemical performance and cycle stability when they are used as lithium-ion battery anode materials. A typical sample of mesoporous Si@C microspheres presents a specific capacity of 1637 and 1375 mA h g−1 at first discharge and charge under a current density of 50 mA g−1. After 100 cycles, the charge capacity remains 1053 mA h g−1 with a coulombic efficiency of 99%, showing good cycle stability of the anode. This finding highlights the potential application of mesoporous Si@C microspheres in lithium-ion battery anode materials.
Co-reporter:Mingxian Liu, Lihua Gan, Wei Xiong, Zijie Xu, Dazhang Zhu and Longwu Chen
Journal of Materials Chemistry A 2014 - vol. 2(Issue 8) pp:NaN2562-2562
Publication Date(Web):2013/12/03
DOI:10.1039/C3TA14445C
We report the development of MnO2/porous carbon microspheres with a partially graphitic structure for high performance supercapacitor electrode materials. Micro- and mesoporous carbon microspheres were fabricated based on a hydrothermal emulsion polymerization and common activation process. Manganese nitrate was introduced into the pores of the carbon microspheres, followed by thermal treatment to transform it into amorphous MnO2. As-prepared MnO2/porous carbon microspheres with high specific surface area (up to 1135 m2 g−1) and regular geometry (0.5–1.0 μm in diameter) benefit fast ion-transport and rapid charge–discharge, and contribute double layer capacitance to the hybrid electrode. Besides, manganese dioxide shows high pseudocapacitive behaviour due to faradaic redox reaction. Furthermore, the introduction of MnO2 greatly promotes the graphitization degree of the carbon matrix. A typical MnO2/carbon sample shows a partially graphitic structure with a very low intensity ratio of Raman D to G band (ID/IG = 0.27), which substantially increases the electronic conductivity and reduces the internal resistance (decreased from 0.42 to 0.20 Ω). As a result, the MnO2/porous carbon microspheres as supercapacitor electrodes exhibit excellent electrochemical performance (459 F g−1 at 1.0 A g−1 and 354 F g−1 at 20.0 A g−1 in 6 M KOH electrolyte). The well-developed MnO2/carbon hybrid materials with a high charge–discharge rate capability coupled with a high electrochemical capacitance highlight the great potential for widespread supercapacitor applications.
Co-reporter:Jiasheng Qian, Mingxian Liu, Lihua Gan, Pranav K. Tripathi, Dazhang Zhu, Zijie Xu, Zhixian Hao, Longwu Chen and Dominic S. Wright
Chemical Communications 2013 - vol. 49(Issue 29) pp:NaN3045-3045
Publication Date(Web):2013/02/27
DOI:10.1039/C3CC41113C
We established a novel and facile strategy to synthesize uniform polymer and carbon nanospheres, the diameters of which can be precisely programmed between 35–105 and 30–90 nm, respectively, via time-controlled formation of colloidal seeds. The carbon nanospheres show promising prospects in high rate performance electrochemical energy storage.
Co-reporter:Mingxian Liu, Jiasheng Qian, Yunhui Zhao, Dazhang Zhu, Lihua Gan and Longwu Chen
Journal of Materials Chemistry A 2015 - vol. 3(Issue 21) pp:NaN11526-11526
Publication Date(Web):2015/04/20
DOI:10.1039/C5TA02224J
In this paper, we report a novel design and synthesis of core–shell ultramicroporous@microporous carbon nanospheres (UMCNs) for advanced supercapacitor electrodes. Polymer colloids (10–14 nm) are obtained by time-controlled polymerization of phloroglucinol and terephthalaldehyde (P/T). UMCNs with ultramicropores in the inner core and abundant micropores in the outer shell are fabricated by the copolymerization of resorcinol and formaldehyde (R/F) on the surfaces of P/T colloids with the presence of ammonia, followed by carbonization and further KOH activation. The as-prepared UMCNs have an adjustable diameter (52–74 nm) and a high specific surface area (up to 2156 m2 g−1). Inter-particle mesoporosity among UMCNs creates ion buffer reservoirs and reduces the ion diffusion distance, while micropores offer highly efficient ion channels and also show high capability for charge accumulation. Moreover, regular ultramicropores benefit the fast transportation and diffusion of electrolyte ions. Consequently, UMCNs with a unique 3D core–shell nanostructure exhibit superb electrochemical performance such as very high specific capacitance (411 F g−1 at 1 A g−1), ultra-high rate capability (charge–discharge operation under an extremely high current density of 100 A g−1), excellent long-term cycle stability (10000 cycles) and reasonable energy density at high power density (5.94 W h kg−1 at 50 kW kg−1) in a 6 M KOH electrolyte. This finding opens up a new window for well-developed carbon nanoarchitectures to support advanced supercapacitor devices for high rate electrochemical energy storage.
Co-reporter:Pranav K. Tripathi, Mingxian Liu, Yunhui Zhao, Xiaomei Ma, Lihua Gan, Owen Noonan and Chengzhong Yu
Journal of Materials Chemistry A 2014 - vol. 2(Issue 22) pp:NaN8544-8544
Publication Date(Web):2014/03/31
DOI:10.1039/C4TA00578C
In this work we prepared hierarchically ordered micro–mesoporous carbon with enlarged uniform micropores, specifically tailored for the high level adsorption of environmental pollutant bisphenol A (BPA). Sizes of both the primary micropore (1.3 nm) and the primary mesopore (9.0 nm) could be tuned by controlling the condensation behavior of phloroglucinol–terephthalaldehyde resin in a tri-constituent system based on evaporation induced self-assembly. As a result of this the special structure was able to develop high surface area (623–1985 m2 g−1) and large pore volume (0.7–2.3 cm3 g−1). By tuning the micropore size to accommodate the molecular dimensions of BPA, an ultra-high adsorption capacity of 1106 mg g−1 was achieved, three times higher than previously reported values. Kinetic studies revealed that high pore interconnectivity and micropore accessibility were the key to unrestricted adsorbate diffusion through the pore channels and the subsequent high level adsorption. This development sheds new light on the importance of the carbon source in the control of pore size in carbons. The materials hold great potential for application in the purification of industrial process water with high level BPA contamination.
