Co-reporter:Bei Liu, Yijiang Liu, Hongbiao Chen, Mei Yang, Huaming Li
Journal of Power Sources 2017 Volume 341() pp:309-317
Publication Date(Web):15 February 2017
DOI:10.1016/j.jpowsour.2016.12.022
•PF-derived porous carbon nanosheets (PFC) was fabricated for supercapacitors.•Oxygen and nitrogen co-doped PFC was simply prepared by direct pyrolysis.•The electrochemical tests exhibited a high volumetric capacitance of 287 F cm−3.•Retention of 96.1% of its initial capacitance was achieved after 10000 cycles.•PFC based supercapacitor exhibits a high volumetric energy density of 14.8 Wh L−1.Biomass-derived O/N-co-doped porous carbons have become the most competitive electrode materials for supercapacitors because of their renewability and sustainability. We herein present a simple approach to fabricate O/N-co-doped porous carbon nanosheets by the direct pyrolysis of Perilla frutescens (PF) leaves. Under optimum pyrolysis temperature (700 °C), the PF leaf-derived carbon nanosheets (PFC-700) having O, N contents of 18.76 at.% and 1.70 at.%, respectively, exhibit a hierarchical pore structure with a moderate BET surface area (655 m2 g−1) and a relatively low pore volume (0.44 cm3 g−1). Such O/N-co-doped porous carbon nanosheets display both high gravimetric capacitance (270 F g−1 at 0.5 A g−1) and high volumetric capacitance (287 F cm−3 at 0.5 A g−1). In addition, the PFC-700-based symmetric supercapacitor offers a high volumetric energy density (14.8 Wh L−1 at 490 W L−1) as well as a high stability (about 96.1% of capacitance retention after 10000 cycles at 2 A g−1).
Co-reporter:
Journal of Heterocyclic Chemistry 2017 Volume 54(Issue 2) pp:
Publication Date(Web):
DOI:10.1002/jhet.2739
A series of directly linked metalloporphyrin–arylimidazole heterodyads (3, 4, and 6) with an arylimidazole unit at the meso- or β-pyrrolic position of the porphyrin were synthesized via Debus–Radziszewsk reaction. Introduction of a copper ion into the porphyrin contributed significantly to the overall stability of the heterodyads. The absorption spectra indicated that the basic electronic characteristics of both individual units (i.e., metalloporphyrin and arylimidazole) were retained in the heterodyads. In addition, strong fluorescence quenching was observed in the case of the heterodyads containing copper(II) porphyrin. Cyclic voltammetric studies revealed that the heterodyads were more difficult to oxidize compared with the pristine metalloporphyrins.
Co-reporter:Xinyu Xu, Yijiang Liu, Yong Gao, Huaming Li
Colloids and Surfaces A: Physicochemical and Engineering Aspects 2017 Volume 529(Volume 529) pp:
Publication Date(Web):20 September 2017
DOI:10.1016/j.colsurfa.2017.06.048
•The preparation method of the Au@silica Janus nanosheets is simple and effective.•The amphiphilicity and emulsification of the Au@silica Janus nanosheets are not affected by the functionalization.•Compared to particle-like Janus catalysts, the Au@silica Janus nanosheets exhibit higher catalytic efficiency.•The recovery of the Au@silica Janus nanosheets is simple, which can be reused with 100 % catalytic activity.We report the preparation of the Au@silica Janus nanosheets by materialization of the emulsion interface and further functionalization with Au nanoparticles. The amphiphilicity and emulsification property of Au@silica Janus nanosheets were not affected by the grown Au nanoparticles. The catalytic performance of the Au@silica Janus nanosheets was explored using the reduction reaction of p-nitrophenol and p-nitroanisol as model reactions in homogenous reaction and emulsion interfacial reaction, respectively. The results indicated that the Au@silica Janus nanosheets exhibited excellent catalytic activity for the reduction reaction of p-nitrophenol in the homogenous reaction. In emulsion interface, the conversion of p-nitroanisol was 16-fold higher than that of the two-phase interface, which could attribute to the expanded active areas and the favorable mass transfer at the emulsion interface. The recovery of the Au@silica Janus nanosheets was simply realized and could be reused with 100 % catalytic activity. Compared with the particle-like Janus catalyst, the Au@silica Janus nanosheets could achieve better catalytic efficiency with a more low content. The conception of emulsion interfacial catalysis with Janus catalysts provides an avenue for conventional heterogeneous reactions.The Au@silica Janus nanosheets with good amphiphilicity and emulsification property were prepared through sequential sol-gel and selective functionalization, which exhibited higher catalytic efficiency at emulsion interface than that of the biphasic interface with a more low content.Download high-res image (146KB)Download full-size image
Co-reporter:Chenggui Tang, Yijiang Liu, Duanguang Yang, Mei Yang, Huaming Li
Carbon 2017 Volume 122(Volume 122) pp:
Publication Date(Web):1 October 2017
DOI:10.1016/j.carbon.2017.07.007
Heteroatom-doped porous carbons have currently been regarded as the promising materials for supercapacitors because of their outstanding contributions in Faradaic capacitance and electrolyte accessibility. In the present study, O/N co-doped porous carbons have been prepared by carbonization of ammonium citrate single precursor followed by KOH activation. The as-synthesized carbon (ACA-800) has a finely-layered schistose architecture together with a high surface O and N-containing functionalities (6.82 at.% O and 1.37 at.% N), a high micropore surface area (1522 m2 g−1) and a balanced mesopore surface area (1138 m2 g−1). Due to their synergistic effects, the ACA-800 electrode displays high-rate capacitive performance with specific capacitance of 297 F g−1 at 100 A g−1, at least 85% of its capacitance (349 F g−1) at 1 A g−1. Moreover, symmetric supercapacitor assembled with such ACA-800 exhibits high energy density of 25.5 W h kg−1 at 923 W kg−1 as well as excellent cycling stability (only 4% of capacitance loss after 10000 cycles with a cell voltage of 1.8 V at a current load of 2 A g−1). Considering the global abundance and low price of ammonium citrate, it can serve as a novel precursor for the mass production of O/N-enriched porous carbons for advanced supercapacitors.Download high-res image (270KB)Download full-size image
Co-reporter:Zhidan Lei, Hongbiao Chen, Mei Yang, Duanguang Yang, Huaming Li
Applied Surface Science 2017 Volume 426(Volume 426) pp:
Publication Date(Web):31 December 2017
DOI:10.1016/j.apsusc.2017.07.183
•A novel B and O-codoped carbon electrocatalyst for ORR was prepared.•The electrocatalyst was prepared by pyrolyzing B and O-rich polymeric network.•The electrocatalyst has high surface area and predominant mesostructure.•The electrocatalyst showed excellent ORR activity in alkaline electrolytes.A low-cost boron- and oxygen-codoped porous carbon electrocatalyst towards oxygen reduction reaction (ORR) has been fabricated by a facile one-step pyrolysis approach, while a boron- and oxygen-rich polymer network was used as precursor. The boron- and oxygen-codoped carbon catalyst with high ORR electrocatalytic activity is comparable to that of Pt/C and is superior to that of catalysts doped solely with boron atoms or with oxygen atoms. Furthermore, the optimized boron- and oxygen-codoped carbon catalyst possesses excellent methanol tolerance and long-term durability in alkaline media. The high electrocatalytic activity of the dual-doped carbon catalysts can be attributed to the synergistic effects of high surface area, predominant mesostructure, abundant active oxygen-containing groups, and effective boron doping. The present results show that this boron- and oxygen-codoping strategy could be as a promising way for the preparation of highly efficient ORR catalysts.Download high-res image (120KB)Download full-size image
Co-reporter:Zhenyu Xu;Yijiang Liu;Hongbiao Chen;Mei Yang
Journal of Materials Science 2017 Volume 52( Issue 13) pp:7781-7793
Publication Date(Web):2017 July
DOI:10.1007/s10853-017-1064-z
In this paper, bamboo-like, O-doped carbon tubes with hierarchical pore structure have been fabricated by the direct pyrolysis of dual cross-linked polydivinylbenzene (PDVB) tubes. The bamboo-like, cross-linked PDVB tubes are firstly synthesized by cationic polymerization of divinylbenzene in cyclohexane using BF3/Et2O complex as the initiator. After a secondary cross-linking being imposed by Friedel–Crafts reaction in CCl4 using anhydrous AlCl3 as the catalyst, the obtained dual cross-linked, carboxylic acid functionalized PDVB tubes are directly subjected to pyrolysis, yielding bamboo-like, O-doped porous carbons. The resultant O-doped porous carbon tubes (BCTF-900, pyrolyzed at 900 °C) exhibit a trimodal pore structure (micro-, meso-, and macropores) with a relatively high specific surface area of 595 m2 g−1 and a low total pore volume of 0.37 cm3 g−1. Such bamboo-like carbon tubes display good volumetric capacitive performance (254 F cm−3 at 0.5 A g−1), moderate volumetric energy density (12.9 Wh L−1 at 428 W L−1), and excellent cycling stability (the capacitance retention has remained at 96.9% after 10000 cycles at 2 A g−1). Due to their unique bamboo-like architecture and trimodal pore structure, the PDVB-derived carbon tubes should have widely application prospect.
Co-reporter:Mei Yang, Yijiang Liu, Hongbiao Chen, Duanguang Yang, and Huaming Li
ACS Applied Materials & Interfaces 2016 Volume 8(Issue 42) pp:28615
Publication Date(Web):October 7, 2016
DOI:10.1021/acsami.6b09811
Metal-free N-doped carbon (NC) materials have been regarded as one of the most promising catalysts for the oxygen reduction reaction (ORR) in alkaline media because of their outstanding ORR catalytic activity, high stability, and good methanol tolerance. Up to now, only a small minority of such catalysts have been synthesized from triazine-based polymeric networks. Herein, we report the synthesis of such NC catalyst by directly pyrolyzing a nitrogen-rich, triazine-based polypyrrole network (TPN). The TPN is fabricated by oxidative polymerization of 2,4,6-tripyrrol-1,3,5-triazine monomer using TfOH as the protonating agent and benzoyl peroxide as the oxidizing agent. The obtained NC-900 (pyrolyzed at 900 °C) catalyst exhibits excellent ORR activity in alkaline media with a high ORR onset potential (0.972 V vs RHE), a large kinetic-limiting current density (15.66 mA cm–2 at 0.60 V), and good MeOH tolerance and durability. The as-synthesized NC-900 material is a potential candidate as a highly active, stable, and low-cost ORR catalyst for alkaline fuel cells.Keywords: dope; fuel cells; netal-free catalysts; ORR; polymeric networks; porous carbon
Co-reporter:Mei Yang, Hongbiao Chen, Duanguang Yang, Yong Gao, Huaming Li
Journal of Power Sources 2016 Volume 307() pp:152-159
Publication Date(Web):1 March 2016
DOI:10.1016/j.jpowsour.2015.12.110
•A novel Fe–N/C electrocatalyst for oxygen reduction reaction (ORR) was prepared.•The electrocatalyst was prepared by pyrolyzing polymeric network and Fe(OAc)2.•The electrocatalyst showed excellent ORR activity in alkaline electrolytes.•The electrocatalyst showed relatively high ORR activity in acidic electrolytes.•The results obtained are significant for the development of new Fe–N/C catalysts.Carbon-supported transition metal/nitrogen (M–N/C) materials are considered as one of the most promising electrocatalysts for the oxygen reduction reaction (ORR) owing to their high ORR electrocatalytic activity, long-term stability, and excellent methanol tolerance. So far only a few examples of such catalysts are prepared from N-containing polymers. Herein, we report a novel Fe–N/C catalyst using a nitrogen-rich polymeric network and iron(II) acetate as the precursors. The porous polymeric network is fabricated by one-step Friedel–Crafts reaction of a low-cost cross-linker, formaldehyde dimethyl acetal, with 2,4,6-tripyrrol-1,3,5-triazine. Compared to commercial Pt/C catalyst, the as-prepared Fe–N/C electrocatalyst exhibits superior ORR activity in alkaline electrolyte, and comparable ORR activity in acidic medium. The results obtained are significant for the development of new Fe–N/C electrocatalysts for fuel cells.We report a novel Fe–N/C catalyst using a nitrogen-rich polymeric network and iron(II) acetate as the precursors. Compared to commercial Pt/C catalyst, the prepared Fe–N/C catalyst exhibits superior ORR activity in alkaline electrolytes, and comparable ORR activity in acidic media. The results obtained are significant for the development of new Fe–N/C catalysts for fuel cells.
Co-reporter:Bei Liu, Hongbiao Chen, Yong Gao, Huaming Li
Electrochimica Acta 2016 Volume 189() pp:93-100
Publication Date(Web):20 January 2016
DOI:10.1016/j.electacta.2015.12.081
•EB-derived porous carbon (ECA) was facilely fabricated for supercapacitors.•ECA shows an extremely high specific surface area of 2273 m2 g−1.•The electrochemical tests exhibited a high specific capacitance of 373 F g−1.•Retention of 94.6% of its initial capacitance was achieved after 10000 cycles.In this work, we present a facile approach to synthesize porous carbon materials via a two-step fabrication process using eulaliopsis binata (EB) as the biomass precursor. The dried EB is directly subjected to pyrolysis at a moderate temperature (500 °C) followed by KOH activation at high temperature (850 °C), giving EB-derived porous carbons. By optimizing the KOH/carbon mass ratio and activation temperature to balance the porosity and capacitance, the resulting porous carbon shows an extremely high specific surface area (2273 m2 g−1) and pore volume (1.19 m3 g−1) as well as excellent capacitive performance with a specific capacitance of 373 F g−1 at 0.5 A g−1. Such low-cost, high-performance, biomass-derived electrode material is potentially useful for high-power supercapacitors.
Co-reporter:Bei Liu, Xiahong Zhou, Hongbiao Chen, Yijiang Liu, Huaming Li
Electrochimica Acta 2016 Volume 208() pp:55-63
Publication Date(Web):1 August 2016
DOI:10.1016/j.electacta.2016.05.020
•LS-derived porous carbon (LSC) was fabricated for supercapacitors.•LSC was prepared by hydrothermal treatment followed by pyrolysis and activation.•The electrochemical tests exhibited a high specific capacitance of 402 F g−1.•Retention of 95.4% of its initial capacitance was achieved after 10000 cycles.•The LSC based supercapacitor exhibits a high energy density of 12.5 Wh kg−1.Biomass-derived porous carbons are widely regarded as one of the most promising electrode materials for supercapacitors owing to their natural abundance and low-cost. Herein, we present a facile approach to synthesize promising porous carbons via a two-step fabrication process using lotus seedpods (LS) as the biomass precursor. Firstly, the LS is hydrothermally treated in a KOH aqueous solution. After filtration and drying, the hydrothermal product is directly subjected to simultaneous pyrolysis and activation, giving LS-derived porous carbon materials. The morphology, structure and textural properties of the carbon materials are investigated by scanning electron microscopy, transmission electron microscopy, and N2 sorption isotherms. The porous carbon prepared under optimal conditions exhibits a relatively high BET surface area of 1813 m2 g−1 and an average pore size of 3.30 nm. Such porous carbon shows outstanding capacitive performance (402 F g−1 at 0.5 A g−1), good rate capability and excellent cycling stability (95.4% of capacitance retention after 10,000 cycles) in 6 M KOH electrolyte. More importantly, the as-assembled symmetric supercapacitor delivers a high energy density of 12.5 Wh kg−1 at power density of 260 W kg−1.
Co-reporter:Xiangzhu He, Shuangming Zhu, Hongbiao Chen, Yongpeng Wang, Huaming Li
Journal of Luminescence 2016 Volume 173() pp:218-222
Publication Date(Web):May 2016
DOI:10.1016/j.jlumin.2016.01.025
In this paper, we demonstrate a new fluorescent turn-on chemodosimeter for Hg2+ determination. The chemodosimeter contains a triphenylimidazole fluorophore and an Hg2+-responsive dithioacetal moiety. In the presence of Hg2+, the probe displays a characteristic turn-on mode at 527 nm in its emission spectrum due to the irreversible Hg2+-promoted deprotection of the dithioacetal group. With the aid of the fluorescence spectrometer, the chemodosimeter in the dimethylformamide/H2O (7/3, v/v) mixed solvent (2.0 μM) exhibits a detection limit of 4.3 nM (S/N=3). Interferences from other common cations associated with Hg2+ analysis are effectively inhibited.
Co-reporter:Ya Peng, Haiwen Yu, Hongbiao Chen, Zhichao Huang, Huaming Li
Polymer 2016 Volume 99() pp:529-535
Publication Date(Web):2 September 2016
DOI:10.1016/j.polymer.2016.07.065
•Triarylimidazole-containing poly(DVT) was synthesized by RAFT polymerization.•Intramolecular cross-linking of poly(DVT) was proceeded with CIM below 50 μM.•Intermolecular cross-linking of poly(DVT) was proceeded with CIM above 500 μM.•Cross-linked poly(DVT) can be de-cross-linked by visible light irradiation.The reversible addition-fragmentation chain transfer (RAFT) polymerization of 1-(4-(4,5-diphenyl-1H-imidazol-2-yl)phenyl)-4-vinyl-1H-1,2,3-triazole (DVT) was carried out in N,N-dimethylformamide at 70 °C using 2-(ethylthiocarbonothioylthio)-2-methylpropanoic acid as the RAFT agent and 2,2′-azobisisobutyronitrile as the initiator to give well-defined poly(DVT) (1). The cross-linking reaction of the obtained (1) was proceeded with K3[Fe(CN)6] and KOH, yielding the intramolecular (2) and intermolecular cross-linked poly(DVT) (3) by tuning the polymer concentrations. The resulting cross-linked poly(DVT) (2) and (3) were de-cross-linked by visible light irradiation in the presence of ethanethiol, giving ethylthio-capped, de-cross-linked poly(DVT) (4) in good yield.The cross-linking reaction of the triarylimidazole-containing polymer (poly(DVT)) (1)was proceeded with K3[Fe(CN)6] and KOH, yielding the intramolecular (2) and intermolecular cross-linked poly(DVT) (3) by tuning the polymer concentration. The resulting cross-linked poly(DVT) (2) and (3) were de-cross-linked by visible light irradiation in the presence of ethanethiol, giving ethylthio-capped, de-cross-linked poly(DVT) (4).
Co-reporter:Jian Tan, Hongbiao Chen, Yong Gao, Huaming Li
Electrochimica Acta 2015 Volume 178() pp:144-152
Publication Date(Web):1 October 2015
DOI:10.1016/j.electacta.2015.08.008
•Citric acid/urea-derived porous carbon (CUA) was fabricated for supercapacitors.•CUA was prepared by microwave-hydrothermal process followed by pyrolysis and activation.•The electrochemical tests exhibited a high specific capacitance of 365 F g−1.•Retention of 98.7% of its initial capacitance was achieved after 10,000 cycles.In this work, we presented a novel approach to synthesize nitrogen-doped porous carbon materials via a three-step fabrication process using citric acid as the carbon source and urea as the nitrogen source. Firstly, hydrochar was synthesized by a microwave-assisted hydrothermal method using citric acid and urea and as the reactants. The hydrochar was then subjected to high-temperature carbonization in Ar atmosphere followed by KOH activation, giving nitrogen-doped porous carbon materials. The morphology, structure, and textural properties of the carbons were investigated by SEM, TEM, N2 sorption isotherms, and XPS. The as-prepared porous carbon possesses a high BET surface area of 2397 m2 g−1 and an average pore size of 1.8 nm. Such N-rich porous carbon shows outstanding capacitive performance (365 F g−1 at 0.5 A g−1), good rate capacitive behavior, and excellent cycling stability, indicating a great potential for supercapacitors.
Co-reporter:Wanqing Li, Duanguang Yang, Hongbiao Chen, Yong Gao, Huaming Li
Electrochimica Acta 2015 Volume 165() pp:191-197
Publication Date(Web):20 May 2015
DOI:10.1016/j.electacta.2015.03.022
Based on the unique electronic properties and high surface area of carbon nanotubes as well as the similar electronegativity of sulfur and carbon, a novel electrocatalyst for the oxygen reduction reaction (ORR) was fabricated by directly annealing oxidized carbon nanotubes and p-benzenedithiol in nitrogen. The structural and chemical properties of the resulting sulfur-doped carbon nanotubes (pSCNTs) were investigated using transmission electron microscopy, X-ray photoelectron spectroscopy and Raman spectroscopy. The catalytic activity of the pSCNTs towards ORR in alkaline medium was evaluated using rotating ring disk electrode voltammetry. The as-synthesized pSCNT-900 (annealed at 900 °C) exhibits excellent electrochemical performance towards ORR with an onset potential of –0.082 V (vs Ag/AgCl), a high kinetic current density of 34.6 mA cm−2 at –0.35 V), a dominant four-electron transfer mechanism (n = 3.71 at –0.35 V), as well as excellent methanol tolerance and durability. The results obtained are significant for the development of S-doped carbon-based catalysts for alkaline fuel cells.
Co-reporter:Tongye Wei, Xiaolin Wei, Yong Gao, Huaming Li
Electrochimica Acta 2015 Volume 169() pp:186-194
Publication Date(Web):1 July 2015
DOI:10.1016/j.electacta.2015.04.082
•BP bark-derived, N-doped porous carbon (BPC) was fabricated for supercapacitors.•BPC was prepared by hydrothermal treatment followed by pyrolysis and activation.•The electrochemical tests exhibited a high specific capacitance of 320 F g−1.•Retention of 94% of its initial capacitance was achieved after 10000 cycles.In this work, we present a facile approach to synthesize nitrogen-doped porous carbon materials via a two-step fabrication process using the stem bark of broussonetia papyrifera (BP) as the biomass precursor. Firstly, the BP stem bark is hydrothermally treated in a KOH aqueous solution. After filtration and drying, the hydrothermal product is directly subjected to simultaneous pyrolysis and activation, giving nitrogen-doped porous carbon materials. The morphology, structure and textural properties of the carbon materials are investigated by scanning electron microscopy, transmission electron microscopy, N2 sorption isotherms, and X-ray photoelectron spectroscopy. The obtained porous carbon exhibits a high BET surface area of 1212 m2 g−1 and an average pore size of 3.8 nm. Such porous carbon shows outstanding capacitive performance (320 F g−1 at 0.5 A g−1), good rate capacitive behavior, and excellent cycling stability due to the synergistic effect of N, O-doped species, indicating a great potential for supercapacitors.
Co-reporter:Xiangzhu He;Duanguang Yang;Hongbiao Chen;Wei Zheng
Journal of Molecular Recognition 2015 Volume 28( Issue 5) pp:293-298
Publication Date(Web):
DOI:10.1002/jmr.2442
In this study, we demonstrated a highly sensitive, selective, and reversible chemosensor for Hg2+ determination. This chemosensor was synthesized by direct condensation of thymin-1-ylacetic acid with zinc tetraaminoporphyrin, which has a porphyrin core as the fluorophore and four thymine (T) moieties as the specific interaction sites for Hg2+. The probe (4T-ZnP) exhibited split Soret bands with a small peak at 408 nm and a strong band at 429 nm in a dimethylformamide/H2O (7/3, v/v) mixed solvent as well as a strong emission band at 614 nm. Upon the addition of Hg2+, the probe displayed strong fluorescence quenching due to the formation of T-Hg2+-T complexes. With the aid of the fluorescence spectrometer, the chemosensor in the dimethylformamide/H2O (7/3, v/v) mixed solvent (0.3 μM) exhibited a detection limit of 6.7 nM. Interferences from other common cations, such as Co2+, K+, Sn2+, Zn2+, Cu2+, Ni2+, Mn2+, Na+, Ca2+, Mg2+, Pb2+, and Cd2+, associated with Hg2+ analysis were effectively inhibited. Copyright © 2015 John Wiley & Sons, Ltd.
Co-reporter:Jun Zhang, Xiaofeng Zhong, Hongbiao Chen, Yong Gao, Huaming Li
Electrochimica Acta 2014 Volume 148() pp:203-210
Publication Date(Web):1 December 2014
DOI:10.1016/j.electacta.2014.10.023
Porous carbon was synthesized by the direct carbonization of full interpenetrating polymer networks (IPNs) of phenol-formaldehyde resin (PF) and poly(methyl methacrylate) (PMMA). The PF/PMMA IPNs were prepared by simultaneous polymerization of PF prepolymer as well as methyl methacrylate and ethylene glycol dimethacrylate monomers in dimethylformamide. During the followed carbonization process, the PF polymeric networks tended to form carbon matrix (carbon precursor) while the PMMA decomposed into gaseous products, leaving pores in carbon matrix (pore-former). The obtained porous carbon has an interconnected pore structure with a high BET surface area of 865 m2 g−1 and an average pore size of 4.4 nm. Such porous carbon shows outstanding capacitive performance (252 F g−1), good rate capacitive behavior, and excellent cycling stability. Due to its unique pore structure, the as-prepared porous carbon shows promise as an electrode material for supercapacitors.
Co-reporter:Hongyan Zhao, Hongbiao Chen, Yong Gao and Huaming Li
CrystEngComm 2014 vol. 16(Issue 32) pp:7507-7514
Publication Date(Web):30 Jun 2014
DOI:10.1039/C4CE00457D
In this study, a self-assembly technique is developed to fabricate ultralong microbelts of sodium 4-(4,5-diphenyl-1H-imidazol-2-yl)benzoate (SDB). The as-prepared SDB microbelts have a belt-like structure with a rectangular cross section. All of the obtained microbelts under the optimum conditions have a relatively uniform size of about 5 μm in width, 2 μm in thickness, and approximately 5 mm in length. Particularly, the length of the SDB microbelts can be readily controlled by adjusting the SDB concentration as well as the aging temperature. In addition, the optical and electrical properties of the as-prepared microbelts are also investigated. These results should be significant in triarylimidazole derivatives crystallization and their potential application in optoelectronic devices.
Co-reporter:Zhihui Fang, Duanguang Yang, Yong Gao and Huaming Li
RSC Advances 2014 vol. 4(Issue 91) pp:49866-49872
Publication Date(Web):18 Sep 2014
DOI:10.1039/C4RA09545F
In this study, we reported a novel, facile, Pickering emulsion-templating method to prepare massage ball-like, hollow-structured Au/SiO2 microspheres. Firstly, oil-in-water Pickering emulsions stabilized by Au@poly(ethylene oxide)-b-poly(4-vinylpyridine) (Au@PEO-b-P4VP) hybrid emulsifier micelles, which were formed by a P4VP/Au complex induced self-assembly process, were generated. Then hollow Au/SiO2 hybrid microspheres with nano-/submicro-sized protrusions on their shells, termed as massage ball-like microspheres, were successfully synthesized using the generated Pickering emulsion as template, in which the P4VP catalyzed hydrolysis and condensation of tetraethoxysilane (TEOS) in the TEOS/n-decanol mixed oil phase occurred at the oil/water interface. As a result, a continuous SiO2 shell was formed. The uneven adsorption of polydisperse hybrid micelles at the oil/water interface as well as the volume shrinkage of the oil phase during the early hydrolysis and condensation of TEOS facilitated the formation of protrusions on the shell surface. After further removal of the polymer components embedded in the shell by calcination, hollow Au/SiO2 hybrid microspheres with micropore/mesopore bimodal porous shells were produced. The as-prepared Au/SiO2 hybrid microspheres were applied as catalysts for the reduction of p-nitrophenol with NaBH4, showing a high catalytic activity with a good recyclability owing to the large specific areas, the easily accessible Au active centres, and the enhanced mass transportation.
Co-reporter:Ping Zhang, Fengyang Deng, Ya Peng, Hongbiao Chen, Yong Gao and Huaming Li
RSC Advances 2014 vol. 4(Issue 88) pp:47361-47367
Publication Date(Web):19 Sep 2014
DOI:10.1039/C4RA08189G
Covalent dynamic gels based on reversible acylhydrazone and disulfide bonds were prepared by crosslinking of benzhydrazide-containing poly(triazole) (PTB) with a novel disulfide-containing dialdehyde (C2) in DMF at ambient temperature. The PTB was synthesized by the metal- and solvent-free click polymerization of diazide and dialkyne monomers followed by treatment with hydrazine hydrate. The as-fabricated polymer gels exhibited both redox and pH stimuli-responsive behaviours. Analysis of the composition-property relationships of these polymer gels, specifically considering the effects of catalysts, molar ratio of benzhydrazide to aldehyde groups (–NH2/–CHO), and gelator concentrations on rheological properties, were performed. Additionally, the gel revealed interesting self-healing properties through acylhydrazone exchange and/or disulfide exchange reactions. Employing this dynamic character, it is possible to regenerate the used gel, and thus it has the potential to perform in a range of dynamic or bioresponsive applications.
Co-reporter:Fugui Xu, Fan Wang, Duanguang Yang, Yong Gao, Huaming Li
Materials Science and Engineering: C 2014 Volume 38() pp:292-298
Publication Date(Web):1 May 2014
DOI:10.1016/j.msec.2014.02.017
•Both the density and the size of Au NPs could be tuned by the grafted PVP content.•Au NPs showed strongly catalytic behavior toward the electrooxidation of L-CySH.•The performance of L-CySH sensor depended on the density and the size of Au NPs.•The L-CySH sensor exhibited a low detection limit and a satisfactory recovery.In this study, Au nanoparticles decorated graphene nanosheets were prepared using poly(vinylpyrrolidone) (PVP) covalently functionalized graphene oxide and chloroauric acid as template and Au precursor, respectively. Both the density and the size of Au nanoparticles deposited on the surface of graphene could be adjusted by the PVP grafting density. The graphene–Au hybrid nanosheets were then applied to fabricate a highly sensitive l-cysteine (L-CySH) electrochemical sensing platform. The cyclic voltammetry results showed that the modified glassy carbon electrode with graphene–Au hybrid nanosheets exhibited strong catalytic activity toward the electrooxidation of L-CySH. The current exhibited a widely linear response ranging from 0.1 to 24 μM with a low detection limit under the optimized conditions. The detection limit of L-CySH could reach as low as 20.5 nM (S/N = 3). The enhanced electrochemical performance of the fabricated sensor was attributed to the combination of the excellent conductivity of graphene and strong catalytic property of uniform Au nanoparticles.Nearly monodisperse Au nanoparticle decorated graphene nanosheets showed excellent catalytic capability toward the electrooxidation of L-CySH.
Co-reporter:Wei Yi;Duanguang Yang;Hongbiao Chen
Journal of Solid State Electrochemistry 2014 Volume 18( Issue 4) pp:899-908
Publication Date(Web):2014 April
DOI:10.1007/s10008-013-2329-3
In this study, we demonstrated a highly sensitive electrochemical sensor for the determination of glucose in alkaline aqueous solution by using nickel oxide single-walled carbon nanotube hybrid nanobelts (NiO–SWCNTs) modified glassy carbon electrode (GCE). The hybrid nanobelts were prepared by the deposition of SWCNTs onto the Ni(SO4)0.3(OH)1.4 nanobelt surface, followed by heat treatment at different temperatures ranging from 400 °C to 600 °C. The NiO–SWCNTs hybrid nanobelts modified electrode prepared at 500 °C displays enhanced electrocatalytic activity towards glucose oxidation, revealing a synergistic effect between the NiO and the deposited SWCNTs. The as-fabricated nonenzymatic glucose sensor exhibits excellent glucose sensitivity (2,980 μA cm−2 mM−1), lower detection limit (0.056 μM, signal/noise [S/N] ratio = 3), and wider linear range (0.5–1,300 μM). Moreover, the sensor has been successfully used for the assay of glucose in serum samples with good recovery, ranging from 96.4 % to 102.4 %.
Co-reporter:Wei Zheng, Xiangzhu He, Hongbiao Chen, Yong Gao, Huaming Li
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy 2014 Volume 124() pp:97-101
Publication Date(Web):24 April 2014
DOI:10.1016/j.saa.2013.12.098
•A triarylimidazole-based colorimetric chemodosimeter for CN− was demonstrated.•The chemodosimeter can recognize CN− with obvious color and fluorescence change.•The chemodosimeter exhibits a very low limit of detection (0.11 μM) for CN−.•The chemodosimeter allows naked eye detection of CN−.In this paper, we demonstrated a highly selective colorimetric chemodosimeter for cyanide anion detection. This chemodosimeter having a triphenylimidazole group as a fluorescent signal unit and a dicyano-vinyl group as a reaction unit was synthesized by the Knoevenagel condensation of 4-(4,5-diphenyl-1H-imidazol-2-yl)benzaldehyde with malononitrile in a reasonable yield. The probe exhibited an intramolecular charge transfer (ICT) absorption band at 420 nm and emission band at 620 nm, respectively. Upon the addition of cyanide anion, the probe displayed a blue-shifted spectrum and loss in color due to the disruption of conjugation. With the aid of the fluorescence spectrometer, the chemodosimeter exhibited a detection limit of 0.11 μM (S/N = 3). Interferences from other common anions associated with cyanide anion analysis were effectively inhibited.Graphical abstract
Co-reporter:Pengcheng Liu, Duanguang Yang, Hongbiao Chen, Yong Gao, Huaming Li
Electrochimica Acta 2013 Volume 109() pp:238-244
Publication Date(Web):30 October 2013
DOI:10.1016/j.electacta.2013.07.157
In this paper, discrete and highly dispersible hollow carbon spheres (HCSs) were prepared by using a confined nanospace pyrolysis method, in which the polystyrene latex particles were step-wisely coated with a phenol-formaldehyde polymer inner shell and a silica outer shell, and monodisperse HCSs were obtained after pyrolysis of this spherical composite and subsequent elimination of the outer silica shell. The electrocatalysts, PtRu nanoparticles supported on HCSs, were prepared by the impregnation and reduction method with sodium borohydride. Uniform and well-dispersed PtRu nanoparticles with a narrow particle size distribution were observed and depended on the total metal loadings. The electrooxidation of methanol on the supported catalysts was investigated at room temperature by electrochemical impedance spectroscopy, chronoamperometry, and cyclic voltammetry, and the results showed that the catalyst with PtRu loading of 15.75 wt% possessed the highest catalytic activity than the other PtRu catalysts.
Co-reporter:Duanguang Yang;Fan Wang;Jing Yan;Yong Gao
Journal of Nanoparticle Research 2013 Volume 15( Issue 6) pp:
Publication Date(Web):2013 June
DOI:10.1007/s11051-013-1762-7
Graphene-based hybrid nanomaterials have recently been investigated and proposed as a promising platform for electronic, optoelectronic, and electrochemical devices because of their high-surface area, remarkable chemical stability, and electrical conductivity. In this study, we demonstrated a facile method for the preparation of graphene/Ni(OH)2 hybrid nanomaterials. First, polymer-functionalized graphene oxide (PGO) was prepared by Cu(I)-catalyzed click coupling of alkyne-functionalized graphene oxide with azide-terminated poly(vinylpyrrolidone). Subsequently, Ni(OH)2 nanoparticles were deposited onto graphene nanosheets using PGO as a template. Upon reduction with NaBH4, graphene/Ni(OH)2 hybrid nanostructures were constructed. The as-prepared graphene/Ni(OH)2 hybrid nanosheets were directly immobilized onto the surface of glassy carbon electrode for glucose determination. The as-fabricated nonenzymatic glucose sensor exhibited a wider linearity range from 0.3 to 750 μM with a detection limit of 30 nM (S/N = 3).
Co-reporter:Duanguang Yang, Pengcheng Liu, Yong Gao, Hui Wu, Yu Cao, Qizhen Xiao and Huaming Li
Journal of Materials Chemistry A 2012 vol. 22(Issue 15) pp:7224-7231
Publication Date(Web):21 Feb 2012
DOI:10.1039/C2JM30237C
In this study, Ni(SO4)0.3(OH)1.4 nanobelts have been synthesized via a simple template-free hydrothermal reaction in an aqueous solution containing nickel sulfate and sodium acetate. It is found that the molar ratio of nickel sulfate to sodium acetate plays a very important role in determining the morphology of the final product. Subsequently, core-shell Ni(SO4)0.3(OH)1.4/C composite nanobelts have been synthesized from the carbonization and polymerization of glucose under mild hydrothermal conditions in the presence of newly produced Ni(SO4)0.3(OH)1.4 nanobelts. The shell thickness of the core-shell nanobelts can be varied from 2 to 18 nm by adjusting the concentration of glucose. Additionally, the structural evolution from core-shell Ni(SO4)0.3(OH)1.4/C to NiO/C has been successfully performed through ex situ heat treatment. The belt-like morphology has still been maintained after heat treatment at 600 °C for 2 h. The as-prepared NiO/C composites were directly immobilized onto the surface of glassy carbon electrode (GCE) for nonenzymatic glucose determination. The fabricated glucose sensor has an ultrasensitive response (149.11 μA mM−1) and a low detection limit of 9.12 nM (signal/noise ratio (S/N) = 3), which are among the best values reported in the literature.
Co-reporter:Liang Xiao, Jiali Wei, Yong Gao, Duanguang Yang, and Huaming Li
ACS Applied Materials & Interfaces 2012 Volume 4(Issue 8) pp:3811
Publication Date(Web):July 6, 2012
DOI:10.1021/am300936a
Gradient stripe patterns of multiwalled carbon nanotubes (MWCNTs) with remarkable regularity over large areas were fabricated by using evaporation-induced self-assembly technique. In this method, a glass coverslip was inclinedly immersed into a suspension of MWCNTs in dichloroethane. By controlling the solvent evaporation temperature, well-defined gradient stripes were formed at the air–solvent–substrate contact line. The effects of several experimental parameters, such as the substrate tilt angle, concentration of MWCNTs, and evaporation temperature, on the regularity of stripes were discussed. A possible stripe formation process was described as a negative feedback of MWCNT concentration caused by a concavely curved shape of the meniscus. Additionally, the strips of MWCNTs on Si/SiO2 substrate were directly used to fabricate field-effect transistor (FET) devices. The electrical properties of the MWCNT-FET devices were also investigated.Keywords: evaporation; field-effect transistor; gradient stripe; mutiwalled carbon nanotubes; pattern; self-assembly;
Co-reporter:Jing Wang, Qiulin Liao, Hongbiao Chen, Duanguang Yang, Yong Gao and Huaming Li
CrystEngComm 2012 vol. 14(Issue 17) pp:5517-5522
Publication Date(Web):21 May 2012
DOI:10.1039/C2CE25068C
In this study, a self-assembly technique assisted with thermoresponsive diblock copolymer poly(N,N-dimethylacrylamide)-b-poly(N-isopropylacrylamide) (PDMA-b-PNIPAM) is developed to fabricate crystalline microtubes of 2-(4′-((4′-vinylbenzyl)oxyl)phenyl)-4,5-diphenylimidazole (VPD). The as-prepared VPD microtubes are identified to have a hollow tubular structure with a rectangular cross section. All the obtained microtubes under optimal conditions have a uniform size of 220 nm in diameter, 20 nm in wall thickness, and 4.5 μm in length. Additionally, the length of the VPD microtubes can be readily controlled by adjusting the concentration of VPD. Furthermore, the VPD microtubes exhibit interesting size-dependent optical properties, of which the UV-vis absorption band shows an obvious red shift compared to that of the monomer. These results should be significant in triphenylimidazole derivative crystallization and their potential applications in optoelectronic devices.
Co-reporter:Qiulin Liao;Zhihua Nie;Hongbiao Chen;Xujun Luo;Yong Gao
Journal of Applied Polymer Science 2012 Volume 126( Issue 3) pp:1146-1151
Publication Date(Web):
DOI:10.1002/app.36941
Abstract
In this study, a novel vinyl polymer containing 2,4,5-triphenylimidazole side groups was synthesized through conventional radical polymerization, which possesses the characteristic of temperature-dependent absorbance in the near-ultraviolet (UV) spectral region. The linear dependence of UV absorbance on temperature was confirmed for the polymer both in solid state and in solution by experiment and also supported by the results of theoretical investigation. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012
Co-reporter:Yonggui Li, Yong Gao, Yu Cao, Huaming Li
Sensors and Actuators B: Chemical 2012 s 171–172() pp: 726-733
Publication Date(Web):
DOI:10.1016/j.snb.2012.05.063
Co-reporter:Yonggui Li, Duanguang Yang, Alex Adronov, Yong Gao, Xujun Luo, and Huaming Li
Macromolecules 2012 Volume 45(Issue 11) pp:4698-4706
Publication Date(Web):May 17, 2012
DOI:10.1021/ma300432c
A facile method for the covalent functionalization of single-walled carbon nanotubes (SWNTs) with thermoresponsive core cross-linked (CCL) polymeric micelles is presented. This method is based on SWNT functionalization as well as polymer self-assembly. The copolymer, poly(N,N-dimethylacrylamide)-b-poly(N-isopropylacrylamide-co-N-acryloxysuccinimide) (PDMA-b-P(NIPAM-co-NAS)), bearing an azide group at the PDMA end, was first prepared by reversible addition–fragmentation chain transfer (RAFT) polymerization. Covalent functionalization of SWNTs with well-defined, azide-derivatized PDMA-b-P(NIPAM-co-NAS) was then accomplished by a nitrene addition reaction. The copolymer-functionalized SWNTs (f-SWNTs) consisted of about 26 wt % copolymer and exhibited relatively high solubility in water. Subsequently, the coassembly of the copolymer and f-SWNT blends was carried out in aqueous solution. It was found that the copolymer chains grafted onto the surface of SWNTs were coassembled with the free chains in solution, leading to thermoresponsive polymeric micelles that adhered to the surface of nanotubes. Upon cross-linking, the copolymer aggregates were stabilized and covalently anchored to SWNTs (SWNT-micelle). The resulting assembled nanostructures were still soluble in water and were characterized by atomic force microscopy (AFM) and transmission electron microscopy (TEM).
Co-reporter:Hongbiao Chen;Jian Zeng;Fengyang Deng;Xujun Luo
Journal of Polymer Research 2012 Volume 19( Issue 6) pp:
Publication Date(Web):2012 June
DOI:10.1007/s10965-012-9880-y
A series of porphyrin-containing polymers with triazole rings as linkers have been successfully synthesized by click polymerization. The polycycloadditions of porphyrin-containing dialkyne 1 and 1,4-diazidobenzene 2 were initiated either by simple heating or by Cu(I)-catalyst, affording polymers P1-P8 with relatively high molecular weight. The polymerization process was monitored by gel permeation chromatography analysis. The polymer prepared by thermally initiated click polymerization has unimodal molecular weight distribution and moderate polydispersity index after prolonging reaction time to 170 h. Compared with the metal-free click polymerization, the rate of molecular weight growth in Cu(I)-catalyzed click polymerization declined, leading to relatively low molecular weight of the resulting polymer. The as-synthesized polymers are soluble in common organic solvents and stable at a temperature up to 350 °C. The photophysical properties of the porphyrin monomer and the polymer were investigated by UV–vis and fluorescence spectroscopy. This approach offers practical advantages over other synthetic methods used to prepare main-chain porphyrin-containing polymers with regard to the absence of byproducts generated during the polymerization reaction.
Co-reporter:Cuixia Wang;Jiao Xu;Yong Gao;Duanguang Yang
Journal of Polymer Research 2012 Volume 19( Issue 6) pp:
Publication Date(Web):2012 June
DOI:10.1007/s10965-012-9895-4
In this study, an acrylate monomer containing two hydroxyl groups, 2,2-bis(hydroxymethyl)butyl acrylate (HBA), was successfully synthesized by acidic hydrolysis of the monomer precursor, (5-ethyl-2,2-dimethyl-1,3-dioxane-5-yl)methyl acrylate (EDMA), which was prepared by esterification reaction between 2,2-dimethyl-5-ethyl-5-hydroxymethyl-1,3-dioxane and acryloyl chloride. Subsequently, poly(HBA) containing pendant diol group was prepared either by direct reversible addition-fragmentation chain transfer (RAFT) polymerization of HBA or by RAFT polymerization of EDMA, followed by deprotection. The RAFT polymerization of both monomers was performed in dioxane using 2-(ethylthiocarbonothioylthio)-2-methyl propanoic acid (EMP) as the RAFT agent and 2,2′-azobis(isobutyronitrile) (AIBN) as the initiator. Kinetic studies demonstrated that the polymerization process of both monomers followed pseudo first-order kinetics with respect to the monomer concentrations. The molecular weight of the resulting polymer increased linearly with monomer conversion, while a low polydispersity was maintained throughout.
Co-reporter:Xinkai Wang;Hongbiao Chen;Chiguang Chen
Fibers and Polymers 2011 Volume 12( Issue 7) pp:
Publication Date(Web):2011 October
DOI:10.1007/s12221-011-0857-y
Thermoplastic polyurethane, based on 4,4′-diphenylmethane diisocyanate and polyether polyol, was degraded by glycol and ethanolamine at 170 °C. Optimum conditions for the glycolysis of thermoplastic polyurethane were investigated by adjusting the ratio of polymer to degradation reagent, glycol to ethanolamine as well as the reaction temperature. The degradation reaction was conducted under nitrogen atmosphere and accelerated by catalysts such as lithium acetate, which was evidenced by lowering the degradation temperature as well as the amounts of degradation reagent. The decomposition products were completely separated into two layers. The upper liquid layer was a polyether polyol, which was characterized by gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The present glycolysis procedure allows a simple recycling of the hydroxyl terminated polyol in pure form.
Co-reporter:Jiao Xu, Duanguang Yang, Wenjun Li, Yong Gao, Hongbiao Chen, Huaming Li
Polymer 2011 Volume 52(Issue 19) pp:4268-4276
Publication Date(Web):1 September 2011
DOI:10.1016/j.polymer.2011.07.015
Covalent dynamic gels based on reversible phenylboronic acid-diol ester bonds were prepared by crosslinking of N,N-dimethylacrylamide-4-((4-vinylbenzyloxy)carbonyl)phenylboronic acid copolymer, poly(VPB-co-DMA), and poly(2,2-bis(hydroxymethyl)butyl acrylate) (PHBA) in several organic solvents at ambient temperature. These gels formed rapidly and revealed typical properties of chemical gels. Analysis of the composition–property relationships of these polymer gels, specifically considering the effects of pH, molar ratio of HBA to VPB units, and gelator concentrations on dynamic rheological properties, were performed. Additionally, the polymer gels can be switched into their starting polymer solutions by adjusting pH of the system. The reversible sol-gel phase transition can be performed for several cycles in a similar way of supramolecular gel. Moreover, the gel revealed interesting self-healing property which occurred autonomously without any outside intervention. Employing this dynamic character, it is possible to regenerate the used gel, and thus has the potential to perform in a range of dynamic or bioresponsive applications.
Co-reporter:Hui Wu, Yong Gao and Huaming Li
CrystEngComm 2010 vol. 12(Issue 11) pp:3607-3611
Publication Date(Web):06 Jul 2010
DOI:10.1039/C002120B
A series of nickel phosphate (Ni3(PO4)2·8H2O) three-dimensional (3D) hexahedronal and flower-like architectures were synthesized via a simple template-free hydrothermal route. Morphology modification can be conveniently realized by varying the concentration of PO43− ion as well as the reaction time and temperature. The as-prepared flower-like architectures consisted of numerous radially oriented 3D hexahedron-like petals, such as willow-leaf, parallelogram, rectangle, and rhombus-like, respectively, with a thickness of 0.7–2 μm, a width of 5–15 μm and a length of 10–30 μm. Meanwhile, a possible mechanism for the transformation of morphology from hexahedron to flower was preliminarily proposed.
Co-reporter:Hongbiao Chen;Hua Xiong;Yong Gao
Journal of Applied Polymer Science 2010 Volume 116( Issue 3) pp:1272-1277
Publication Date(Web):
DOI:10.1002/app.31495
Abstract
Covalent functionalization of multiwalled carbon nanotubes (MWNTs) with polybutadiene was accomplished by coupling of isocyanate-decorated MWNTs with hydroxyl-terminated polybutadiene (HTPB) in dry toluene. The MWNT precursor, isocyanate-functionalized MWNTs, was prepared by directly reacting commercial hydroxyl functionalized MWNTs with excess toluene 2,4-diisocyanate (TDI). HTPBs with different molecular weights (Mn = 1900, 2600, and 3600 g/mol) were subjected to this coupling reaction, resulting in the formation of polymer functionalized MWNTs. FTIR spectroscopy was utilized to follow the introduction and consumption of isocyanate groups on the MWNTs. Thermogravimetric analysis (TGA) indicated that HTPB was successfully grafted onto MWNT surface, with the final products having a polymer weight percentage of around 30 wt %. Transmission electron microscopy (TEM) was utilized to image the polymer functionalized MWNTs, showing relatively uniform polymer coatings presented on the surface of MWNTs. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Co-reporter:Yong Gao ; Guiling Song ; Alex Adronov
The Journal of Physical Chemistry C 2010 Volume 114(Issue 39) pp:16242-16249
Publication Date(Web):September 3, 2010
DOI:10.1021/jp104894a
Covalent grafting of acrylate-functionalized single-walled carbon nanotubes (SWCNTs) with poly(methyl methacrylate) was accomplished by emulsion polymerization using sodium dodecylbenzene sulfonate (SDBS) as an emulsifying agent. The acrylate-functionalized SWCNTs with polymerizable vinyl groups on their surfaces were prepared by a reaction sequence involving oxidation, hydroxylation, and vinylation reactions. The as-prepared acrylate-functionalized SWCNTs were then dispersed in water in the presence of SDBS, resulting in the exfoliation of SWCNTs into small bundles of approximately 2−6 tubes and the simultaneous formation of SWCNT micelles. Subsequent addition of methyl methacrylate resulted in its absorption into the SWCNT micelles due to the interactions between the monomer and the nanotube surface. Grafting copolymerization of methyl methacrylate with the vinyl groups on the SWCNT surface was subsequently performed in the micelles to produce poly(methyl methacrylate)-functionalized SWCNTs. Thermogravimetric analysis indicated that the average polymer content in the functionalized SWCNTs ranged from 42 to 63 wt %, depending on the time of monomer pre-emulsion.
Co-reporter:Jinyao Liu;Zhihua Nie;Yong Gao;Alex Adronov
Journal of Polymer Science Part A: Polymer Chemistry 2008 Volume 46( Issue 21) pp:7187-7199
Publication Date(Web):
DOI:10.1002/pola.23026
Abstract
Covalent functionalization of alkyne-decorated multiwalled carbon nanotubes (MWNTs) with a well-defined, azide-derivatized, thermoresponsive diblock copolymer, poly(N,N-dimethylacrylamide)-poly(N-isopropylacrylamide) (PDMA-PNIPAM) was accomplished by the Cu(I)-catalyzed [3 + 2] Huisgen cycloaddition. It was found that this reaction could simultaneously increase the molecular size and bonding density of grafted polymers when PDMA-PNIPAM micelles were employed in the coupling system. On the other hand, attachment of molecularly dissolved unimers of high-molecular weight onto the nanotube resulted in low-graft density. The block copolymer bearing azide groups at the PDMA end was prepared by reversible addition–fragmentation transfer polymerization, which formed micelles with a diameter of ∼40 nm at temperatures above its critical micelle temperature. Scanning electron microscopy was utilized to demonstrate that the coupling reaction was successfully carried out between copolymer micelles and alkyne-bearing MWNTs. FTIR spectroscopy was utilized to follow the introduction and consumption of alkyne groups on the MWNTs. Thermogravimetric analysis indicated that the functionalized MWNTs consisted of about 45% polymer. Transmission electron microscopy was utilized to image polymer-functionalized MWNTs, showing relatively uniform polymer coatings present on the surface of nanotubes. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7187–7199, 2008
Co-reporter:Mei Yang, Yong Gao, Huaming Li, Alex Adronov
Carbon 2007 Volume 45(Issue 12) pp:2327-2333
Publication Date(Web):October 2007
DOI:10.1016/j.carbon.2007.07.021
Covalent functionalization of multiwalled carbon nanotubes (MWCNTs) with polyamide 6 was accomplished by anionic ring-opening polymerization of ε-caprolactam in the presence of sodium caprolactamate as a catalyst and caprolactam functionalized MWCNTs as an initiator. The initiator precursor, isocyanate functionalized MWCNTs, was prepared by directly reacting commercial hydroxyl functionalized MWCNTs with excess toluene 2,4-diisocyanate. This anionic ring-opening polymerization was found to occur in a highly efficient manner at relatively low reaction temperature (170 °C) and short reaction times (6 h). FTIR spectroscopy was utilized to follow the introduction and consumption of isocyanate groups on the MWCNTs. Thermogravimetric analysis indicated that the polyamide 6 was successfully grown from the MWCNT surface, with the final products having a polymer weight percentage of ca. 40–65 wt%. Transmission electron microscopy was utilized to image the polymer-functionalized MWCNTs, showing relatively uniform polymer coatings presented on the surface of MWCNTs.
Co-reporter:Yong Gao;Xiayu Wang
Polymer International 2007 Volume 56(Issue 8) pp:
Publication Date(Web):20 MAR 2007
DOI:10.1002/pi.2227
Atom transfer radical polymerization of styrene was conducted with bromoacetylated syndiotactic polystyrene as macroinitiator and copper bromide combined with N,N,N′,N′,N′-pentamethyldiethylenetriamine as catalyst. A two-stage process has been developed to synthesize the macroinitiator. First, syndiotactic polystyrene (sPS) was functionalized in the side phenyl rings with acetyl groups using the Friedel–Crafts reaction; second, the acetyl groups were converted to bromoacetyl groups by an acid-catalyzed halogenation reaction. The initiator was found to be active in the polymerization of styrene, leading to the production of graft chains with well-defined structure. The molecular weight and molecular weight distribution of the graft chains were determined using gel permeation chromatography after cleaving from the sPS backbone using peroxide acid oxidation followed by hydrazine-catalyzed hydrolysis. The results indicated that the polymerization process was characteristic of a ‘living’ nature. Copyright © 2007 Society of Chemical Industry
Co-reporter:Yong Gao;Hua-Ming Li;Feng-Shou Liu;Xia-Yu Wang
Journal of Polymer Research 2007 Volume 14( Issue 4) pp:291-296
Publication Date(Web):2007 August
DOI:10.1007/s10965-007-9109-7
Benzoylated syndiotactic polystyrene, a functional polymer bearing benzophenone(BP) moiety, has been synthesized in a heterogeneous process by using carbon disulfide as the dispersing medium, and benzoyl chloride and anhydrous aluminum chloride as benzoylating agent and catalyst, respectively. The benzoylation reaction can be well controlled and the resultant polymer was characterized by FTIR and NMR spectroscopy. The incorporation of benzoyl groups into syndiotactic polystyrene was found to have a profound effect on the thermal properties of these new materials. The melting point and the degree of crystallinity decreased by the presence of benzoyl groups, while the glass transition temperature increased.
Co-reporter:Duanguang Yang, Pengcheng Liu, Yong Gao, Hui Wu, Yu Cao, Qizhen Xiao and Huaming Li
Journal of Materials Chemistry A 2012 - vol. 22(Issue 15) pp:NaN7231-7231
Publication Date(Web):2012/02/21
DOI:10.1039/C2JM30237C
In this study, Ni(SO4)0.3(OH)1.4 nanobelts have been synthesized via a simple template-free hydrothermal reaction in an aqueous solution containing nickel sulfate and sodium acetate. It is found that the molar ratio of nickel sulfate to sodium acetate plays a very important role in determining the morphology of the final product. Subsequently, core-shell Ni(SO4)0.3(OH)1.4/C composite nanobelts have been synthesized from the carbonization and polymerization of glucose under mild hydrothermal conditions in the presence of newly produced Ni(SO4)0.3(OH)1.4 nanobelts. The shell thickness of the core-shell nanobelts can be varied from 2 to 18 nm by adjusting the concentration of glucose. Additionally, the structural evolution from core-shell Ni(SO4)0.3(OH)1.4/C to NiO/C has been successfully performed through ex situ heat treatment. The belt-like morphology has still been maintained after heat treatment at 600 °C for 2 h. The as-prepared NiO/C composites were directly immobilized onto the surface of glassy carbon electrode (GCE) for nonenzymatic glucose determination. The fabricated glucose sensor has an ultrasensitive response (149.11 μA mM−1) and a low detection limit of 9.12 nM (signal/noise ratio (S/N) = 3), which are among the best values reported in the literature.
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