Co-reporter:Xin Xu, Sikan Peng, Shanfu Lu, Jian Gong, Jin Zhang, Wanxia Huang, Yan Xiang
Journal of Power Sources 2017 Volume 354(Volume 354) pp:
Publication Date(Web):30 June 2017
DOI:10.1016/j.jpowsour.2017.04.006
•Ag/C based alkaline cathode was prepared for the bipolar membrane fuel cell.•The microstructure of the Ag/C catalyst layer was modulated by ionomer content.•3D structure of the catalyst layer was characterized by nano-CT.Ag/C is evaluated as a cathode catalyst for a bipolar membrane fuel cell (BPMFC). The microstructure of the cathode catalyst layer is modulated via ionomer content, and the effects on BPMFC performance are studied. When the ionomer content is increased from 10 wt% to 30 wt%, the fuel cell performance is optimized at 19.3 mW/cm2 with an ionomer content of 20 wt%. Electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) are conducted on the catalyst layer. EIS indicates that the charge transfer resistance is minimum, while CV suggests that the highest electrocatalytic activity of the catalyst is achieved with an ionomer content of 20 wt%. The microstructure of the catalyst layer is characterized using scanning electron microscopy (SEM) and nanometer-scale X-ray computed tomography (nano-CT). The SEM results show that excess ionomer cover on the surface of the catalyst, and the catalyst seems to form larger aggregates. Nano-CT, however, produces quite different results. The reconstructed 3D image of the catalyst layer reveals that the Ag/C catalyst tends to aggregate at low ionomer content. When the ionomer content is increased from 10 wt% to 30 wt%, the average diameter of the catalyst aggregation decreases from 313 nm to 210 nm.With the increase of the ionomer content in the catalyst layer, the catalyst is better dispersed.Download high-res image (208KB)Download full-size image
Co-reporter:Yang Lv, Jin Zhang, Zhaoqian Lv, Chunxiao Wu, Yiyang Liu, Haining Wang, Shanfu Lu, Yan Xiang
Electrochimica Acta 2017 Volume 253(Volume 253) pp:
Publication Date(Web):1 November 2017
DOI:10.1016/j.electacta.2017.09.005
•Bi nanoparticles are uniformly deposited on KOH-etched carbon felts.•KOH-etched carbon felts and Bi nanoparticles co-catalyze V2+/V3+ redox reaction.•Single cell tests demonstrate CFE-Bi as a promising electrode in VRFB.In this work, the electrochemical activity of carbon felt (CF) for the V2+/V3+ redox reaction is improved by combining KOH-etched pretreatment with uniform Bi nanoparticles deposition. CF is functionalized by the KOH activated pretreatment, resulting in micropores structure on the surface and an increase of oxygen-containing functional groups up to 16.49%. The micropores structure and high content of oxygen-containing functional groups of KOH-etched carbon felt (CFE) promote the uniform distribution of Bi nanoparticles on the surface of CFE with an average particle size of 45 nm. The resulting carbon felt (CFE-Bi) significantly enhances the electrochemical activity for V2+/V3+ redox couple because of the synergistic catalysis between the CFE and the Bi nanoparticles. The peak potential separation (ΔEp) and the charge transfer resistance of CFE-Bi is 182 mV and 0.160 Ω cm2, which are much lower than that of CF (427 mV and 3.238 Ω cm2) under the same conditions. Moreover, the energy efficiency of VRFB based on the CFE-Bi as negative electrode achieves 79.3% at 160 mA cm−2, which is 36.2% higher than that of the VRFB with raw carbon felt. Overall, CFE-Bi is a promising electrode for the V2+/V3+ redox couple reaction in VRFB.Download high-res image (117KB)Download full-size image
Co-reporter:Jiangju Si;Haining Wang;Shanfu Lu;Xin Xu;Sikan Peng
Journal of Materials Chemistry A 2017 vol. 5(Issue 8) pp:4003-4010
Publication Date(Web):2017/02/21
DOI:10.1039/C6TA09277B
To resolve the trade-off between conductivity and stability in anion-exchange membranes (AEMs), we proposed a strategy to modulate the membrane morphology from isolated ionic clusters to interconnected channels by precise adjustment of the amphiphilic architectures. From the perspective of AEM molecular designing, by synchronously increasing the amphiphilic segments, well-connected conductive nano-channels, comprising overlapped larger hydrophilic domains (35–40 nm), were constructed and validated by percolation theory. The whole synthesis process was green, avoiding the toxic chloromethyl methyl ether route. The unique molecular, spatial and micro-structures enabled the membranes to exhibit excellent performance. The connective hydrophilic channels significantly enhanced the conductivity, while the increasing hydrophobicity reduced the water uptake and swelling, improving the dimensional and chemical stability of the membranes. This strategy successfully solves the trade-off issue between conductivity and stability in AEMs.
Co-reporter:Yiyang Liu;Shanfu Lu;Haining Wang;Chunmei Yang;Xin Su
Advanced Energy Materials 2017 Volume 7(Issue 8) pp:
Publication Date(Web):2017/04/01
DOI:10.1002/aenm.201601224
A tungsten–cobalt heteropolyacid simultaneously acts as the electrolyte in both the positive and negative compartments of an aqueous redox flow battery. The heteropolyacid provides all of the necessary redox pairs and charge carriers for the battery. A high coulombic efficiency of 99% and an energy efficiency of 86% are achieved. Additionally, at a current density of 25 mA cm–2, a specific energy of 15.4 W h L–1 is obtained.
Co-reporter:Chunxiao Wu, Shanfu Lu, Haining Wang, Xin Xu, Sikan Peng, Qinglong Tan and Yan Xiang
Journal of Materials Chemistry A 2016 vol. 4(Issue 4) pp:1174-1179
Publication Date(Web):27 Nov 2015
DOI:10.1039/C5TA08593D
A novel kind of effective vanadium ion-suppressed polysulfone–polyvinylpyrrolidone (PSF–PVP) membrane with high ion selectivity, superior stability and low cost is designed and constructed for vanadium redox flow batteries (VRFBs). The VRFB with the PSF–PVP–50 membrane exhibits impressive coulombic efficiency (98%) as well as energy efficiency (89%), and outstanding stability during the 2000 h continuous charge–discharge cycling test.
Co-reporter:Qiushi Li, Jian Gong, Sikan Peng, Shanfu Lu, Pang-Chieh Sui, Ned Djilali, Yan Xiang
Journal of Power Sources 2016 Volume 307() pp:358-367
Publication Date(Web):1 March 2016
DOI:10.1016/j.jpowsour.2016.01.016
•2-D model for bipolar membrane (BPM) fuel cell with membrane reaction interface.•Theoretical design strategies of BPM affecting self-humidification are found.•Enhanced self-humidification behavior obtained in wider work condition.The bipolar membrane fuel cells (BPMFCs), which have a unique acid-alkaline jointed membrane electrode assembly (MEA) structure, have demonstrated their great potential for self-humidification during operation. Although the self-humidification ability of such bipolar membranes (BPMs) has recently been validated by a one-dimensional BPM model, the transport mechanism and the formation of self-humidification in the MEAs are not well understood. In the present study, a two-dimensional cross-channel MEA model is developed to elucidate the mechanisms and enhancement of water transport on self-humidification with comprehensive consideration of the three electrochemical reaction zones. The water–formation interface model has been successfully investigated by theoretical and experimental interface reaction kinetics, streamlines of water flux present the formation process and mechanism of self-humidification. A critical current (voltage) value, beyond which self-humidification is initiated, is identified. It is also found that such critical current (voltage) can be adjusted by changing the membrane thickness and the water uptake property of the ionomer. It is concluded that fabricating BPMs with proper membrane thickness and water uptake property are effective strategies to enhance the water management and cell performance in BPMFCs.
Co-reporter:Xin Xu, Haining Wang, Shanfu Lu, Sikan Peng and Yan Xiang
RSC Advances 2016 vol. 6(Issue 49) pp:43049-43055
Publication Date(Web):26 Apr 2016
DOI:10.1039/C6RA07318B
A phosphotungstic acid (HPW) self-anchored hybrid proton exchange membrane (PES/PVP-HPW) is prepared and evaluated in direct methanol fuel cells (DMFCs). The proton conductivity of the hybrid membrane is 0.045 S cm−1 at 25 °C, and reaches 0.078 S cm−1 at 80 °C. The hybrid membrane shows a methanol permeability of 1.65 × 10−6 cm2 s−1. The stability test for the hybrid membrane in 2 M methanol at 50 °C for about 100 h reveals that HPW is well immobilized in the hybrid membrane. The DMFC based on the PES/PVP-HPW hybrid membrane with a thickness of 55 μm exhibits comparable performance of 132 mW cm−2 to that of Nafion212 at 80 °C. The effects of the hybrid membrane thickness and methanol concentration on DMFCs performance are evaluated. The optimal methanol concentration and thickness of the membrane is about 1–2 M and 55 μm, respectively. Furthermore, a 130 h stability test for DMFC with PES/PVP-HPW demonstrates that the hybrid membrane is quite stable, which indicates that PES/PVP-HPW is an attractive low-cost alternative proton exchange membrane to Nafion® for portable power sources.
Co-reporter:Siyuan Rao;Zhibin Guo;Dawei Liang;Deliang Chen;Yuan Li
Advanced Materials 2015 Volume 27( Issue 16) pp:2668-2673
Publication Date(Web):
DOI:10.1002/adma.201405737
Co-reporter:Zhibin Guo, Ruijie Xiu, Shanfu Lu, Xin Xu, Shichun Yang and Yan Xiang
Journal of Materials Chemistry A 2015 vol. 3(Issue 16) pp:8847-8854
Publication Date(Web):13 Mar 2015
DOI:10.1039/C5TA00415B
A submicro-pore containing proton exchange membrane (PEM) consisting of poly(ether sulfones) (PES) and polyvinylpyrrolidone (PVP) was successfully prepared through a scalable polymer blending method with monodispersed SiO2 solid spheres as a hard template. After doping with phosphoric acid (PA), an outstanding balance between proton conductivity and mechanical strength in these blends is obtained. The tensile strength of all the porous PES/PVP membranes ranges from 5.98 to 3.69 MPa with an increasing content of SiO2 from 10 wt% to 50 wt%, which satisfies the mechanical requirements of high-temperature proton exchange membrane fuel cells (PEMFCs). A proton conductivity of 0.09 S cm−1 is obtained for the as prepared composite membrane with a PA doping level of 350 wt% at 180 °C under anhydrous conditions, comparable with the state-of-the-art PBI/PA membranes. The mechanism for the “balanced” properties is that after the PA doping treatment, the mechanical strength satisfies the requirements of high-temperature PEMFCs with a decreased content of PVP at 50 wt%, while the proton conductivity is improved under the cooperative proton transfers both along the “bonded acid” caged inside the pores and the PA-rich domain formed by “free acid” in the submicro-pores. Furthermore, the PEM fuel cell with PA doped porous PES/PVP exhibits a power density of 454 mW cm−2 at 180 °C H2/O2 without external humidification. A fuel cell performance of ∼520 mV at 0.2 A cm−2 is maintained for 150 h without obviously decreasing. The submicro-pore containing PES/PVP blends allowed for a higher PA doping level, and consequently, enhanced proton conductivity, as well as improved mechanical strength and cell performance, showing potential for use as an alternative high-temperature PEM for fuel cells under anhydrous conditions.
Co-reporter:Haining Wang, Shanfu Lu, Yiwen Zhang, Fei Lan, Xin Lu and Yan Xiang
Journal of Materials Chemistry A 2015 vol. 3(Issue 12) pp:6282-6285
Publication Date(Web):17 Feb 2015
DOI:10.1039/C5TA00359H
THF was investigated as a suitable solvent to disperse pristine graphene due to the van der Waals interaction. THF was therefore chosen as the solvent to successfully synthesize Pd particles with a diameter of 1.8 nm on graphene which exhibited improved electrocatalytic activities and stabilities for formic acid electro-oxidation.
Co-reporter:Xin Xu, Haining Wang, Shanfu Lu, Zhibin Guo, Siyuan Rao, Ruijie Xiu, Yan Xiang
Journal of Power Sources 2015 Volume 286() pp:458-463
Publication Date(Web):15 July 2015
DOI:10.1016/j.jpowsour.2015.04.028
•A PES-PVP blend membrane with improved Tg is prepared.•A high proton conductivity of 0.21 S/cm is obtained for PA/PES-PVP 80% at 180 °C without extra humidification.•Fuel cells with PA/PES-PVP membrane demonstrate promising performance and outstanding stability.A high-temperature proton exchange membrane, poly(ethersulphone)-poly(vinyl pyrrolidone) (PES-PVP) blend membrane is successfully prepared by scalable polymer blending method. The physical properties of blend membrane are characterized by DSC, TG and tensile strength test. The DSC and TG results indicate PES-PVP blend membranes possess excellent thermal stability. After phosphoric acid (PA) doping treatment, the blend membrane shows enhanced proton conductivity. PA doping level and volume swelling ratio of the blend membrane are found to be positively related to the PVP content. A high proton conductivity of 0.21 S/cm is achieved at 180 °C for PA doped PES-PVP 80% with a PA doping level of 9.1. PEM fuel cell based on PA doped PES-PVP 80% membrane shows a high power density of 850 mW/cm2 and outstanding stability at 180 °C without extra humidification.
Co-reporter:Sikan Peng, Xin Xu, Shanfu Lu, Pang-Chieh Sui, Ned Djilali, Yan Xiang
Journal of Power Sources 2015 Volume 299() pp:273-279
Publication Date(Web):20 December 2015
DOI:10.1016/j.jpowsour.2015.08.104
•Bipolar membrane fuel cells fabricated with a composite acidic–alkaline membrane.•Self humidifying operation demonstrated with completely dry reactant gas feed.•Faster kinetics with alkaline cathode allows operation with non-Pt catalyst.•Theoretical analysis of factors controlling water transport and self-humidification.To maintain membrane hydration and operate effectively, polymer electrolyte membrane fuel cells (PEMFCs) require elaborate water management, which significantly increases the complexity and cost of the fuel cell system. Here we propose a novel and entirely different approach to membrane hydration by exploiting the concept of bipolar membranes. Bipolar membrane (BPM) fuel cells utilize a composite membrane consisting of an acidic polymer electrolyte membrane on the anode side and an alkaline electrolyte membrane on the cathode side. We present a novel membrane electrode assembly (MEA) fabrication method and demonstrate experimentally and theoretically that BPM fuel cells can (a) self-humidify to ensure high ionic conductivity; and (b) allow use of non-platinum catalysts due to inherently faster oxygen reduction kinetics on an alkaline cathode. Our Pt-based BPM fuel cell achieves a two orders of magnitude gain in power density of 327 mW cm−2 at 323 K under dry gas feed, the highest power output achieved under anhydrous operation conditions. A theoretical analysis and in situ measurements are presented to characterize the unique interfacial water generation and transport behavior that make self-humidification possible during operation. Further optimization of these features and advances in fabricating bipolar MEAs would open the way for a new generation of self-humidifying and water-management-free PEMFCs.
Co-reporter:Jiangju Si, Dawei Liang, Dan Kong, Sufang Wu, Lan Yuan, Yan Xiang, Lei Jiang
Carbohydrate Polymers 2015 Volume 117() pp:211-214
Publication Date(Web):6 March 2015
DOI:10.1016/j.carbpol.2014.08.118
•Fluorescent labeling glycoprotein CPC was synthesized through graft copolymerization.•CPC could be localized and persisted specifically in the cytoplasm of living cells.•CPC was highly resistant to photo bleaching, the fluorescence was remained stable.•CPC was bio-compatible and in zero grade cytotoxicity as quantified by MTT assay.To maintain the virtue of good optical property and discard the dross of conventional fluorescent staining dyes, we provide a strategy for designing new fluorescent scaffolds. In this study, a novel fluorescent labeling glycoprotein (chitosan-poly-l-cysteine, CPC) was synthesized through graft copolymerization. CPC gives emission peak at 465–470 nm when excited at 386 nm. The submicro-scale CPC microspheres could be localized and persisted specifically in the cytoplasm of living cells, with strong blue fluorescence. Moreover, CPC was highly resistant to photo bleaching, the fluorescence was remained stable for up to 72 h as the cells grew and developed. The glycoprotein CPC was bio-compatible and in zero grade cytotoxicity as quantified by MTT assay. The fluorescent labeling process with our newly designed glycoprotein CPC is exceptionally efficient.
Co-reporter:Sikan Peng
The Journal of Physical Chemistry C 2015 Volume 119(Issue 43) pp:24276-24281
Publication Date(Web):October 8, 2015
DOI:10.1021/acs.jpcc.5b08031
The polarization curves of low-temperature fuel cells, such as polymer electrolyte membrane fuel cells, typically have three distinct regimes dictated by certain limiting factors. These kinetic, ohmic, and concentration-loss regimes have overpotentials that are dictated by electrochemical activation, ohmic loss, and reactant concentration, respectively. However, a peculiar polarization curve with a deviated concentration loss regime was recently presented for alkaline anion-exchange membrane fuel cells (AEMFCs), and the cause of this deviation remains unknown to date. In this work, a 2D, steady-state H2/O2 model was developed to simulate transport and reactions in an AEMFC in order to explore the origin and mechanism of deviations in the polarization curve. According to the model, the charge transfer and hydroxyl ion transport resistances in the cathode catalyst layer were rate-limiting factors and contributed to the deviated concentration loss above ∼450 mA cm–2, which was observed in baseline simulations. Improving water management in the cathode catalyst layer was found to be an effective strategy for mitigating the deviated concentration loss and enhancing cell performance, potentially enabling high-performance AEMFCs in the future.
Co-reporter:Siyuan Rao, Kae Jye Si, Lim Wei Yap, Yan Xiang, and Wenlong Cheng
ACS Nano 2015 Volume 9(Issue 11) pp:11218
Publication Date(Web):October 20, 2015
DOI:10.1021/acsnano.5b04784
Natural cell membranes can directionally and selectively regulate the ion transport, which is critical for the functioning of living cells. Here, we report on the fabrication of an artificial membrane based on an asymmetric nanoparticle superlattice bilayered nanosheet, which exhibits similar ion transport characteristics. The superlattice nanosheets were fabricated via a drying-mediated self-assembly of polystyrene-capped gold nanoparticles at the liquid–air interface. By adopting a layer-by-layer assembly process, an asymmetric nanomembrane could be obtained consisting of two nanosheets with different nanoparticle size. The resulting nanomembranes exhibit an asymmetric ion transport behavior, and diode-like current–voltage curves were observed. The asymmetric ion transport is attributed to the cone-like nanochannels formed within the membranes, upon which a simulation map was established to illustrate the relationship between the channel structure and the ionic selectivity, in consistency with our experimental results. Our superlattice nanosheet-based design presents a promising strategy for the fabrication of next-generation smart nanomembranes for rationally and selectively regulating the ion transport even at a large ion flux, with potential applications in a wide range of fields, including biosensor devices, energy conversion, biophotonics, and bioelectronics.Keywords: bilayer; ionic selectivity; nanochannel; nanoparticle superlattice; nanosheets;
Co-reporter:Zhibin Guo, Dawei Liang, Siyuan Rao, Yan Xiang
Nano Energy 2015 Volume 11() pp:654-661
Publication Date(Web):January 2015
DOI:10.1016/j.nanoen.2014.11.026
•We illustrated a novel photovoltaic system with improved photoelectric performance.•Input flickering light can be modulated into regular photoelectric signals with this system.•We demonstrated a possible mechanism for enhanced photocurrent recorded.•We proposed a bypass pathway model of bR photocycle from M412 to B570 state.To mimic the stack structure of granum, for the first time we demonstrate bacteriorhodopsin (bR)/gold nanoparticles (AuNPs) heterogeneous multilayers to perform as a novel photovoltaic stack system with improved photoelectric performance. Upon a cooperative control of the diameter of AuNPs and the stacking layers, the photocurrent can be effectively regulated to reach about 350 nA cm−2. The possible mechanism for enhanced photocurrent recorded in our system is revealed by analyzing the flash kinetics of photocycle intermediates M412, O640, and J600 of bR layers, which are accelerated under proper AuNPs in this stacking structure. A bypass photocycle model of bR photocycle from M412 to B570 state is proposed and supported by tested accumulation of M412 and O640 intermediate during the bR photocycle process. Interestingly, with this stack system, the input flickering light can be effectively modulated into regular photoelectric signals that are well controlled under different flickering frequency and proton concentration gradient. Based on above results, this system potentially serves as solar energy converter to power nano-devices.
Co-reporter:Siyuan Rao;Shanfu Lu;Zhibin Guo;Yuan Li;Deliang Chen
Advanced Materials 2014 Volume 26( Issue 33) pp:5846-5850
Publication Date(Web):
DOI:10.1002/adma.201401321
Co-reporter:Shanfu Lu;Xin Xu;Jin Zhang;Sikan Peng;Dawei Liang;Haining Wang
Advanced Energy Materials 2014 Volume 4( Issue 17) pp:
Publication Date(Web):
DOI:10.1002/aenm.201400842
Co-reporter:Shanfu Lu, Chunxiao Wu, Dawei Liang, Qinglong Tan and Yan Xiang
RSC Advances 2014 vol. 4(Issue 47) pp:24831-24837
Publication Date(Web):15 Apr 2014
DOI:10.1039/C4RA01775G
A novel polymer–inorganic composite membrane, Nafion–[CS–PWA]n (n = the number of bilayers), was prepared by a layer-by-layer self-assembly technique with polycation chitosan (CS) and negatively charged phosphotungstic acid (PWA) for vanadium redox flow battery applications. The UV-visible spectra and SEM results showed that the CS–PWA multilayer was successfully fabricated on the surface of the Nafion membrane, and the FTIR result showed that there was a strong interaction between the CS and PWA molecules. The obtained Nafion–[CS–PWA]n showed much lower vanadium ion permeability compared with the pristine Nafion membrane. Accordingly, the VRFB with the Nafion–[CS–PWA]3 membrane exhibited higher coulombic efficiency (CE) and energy efficiency (EE) together with a slower self-discharge rate than that of the pristine Nafion212 system.
Co-reporter:Shanfu Lu, Di Cao, Xin Xu, Haining Wang and Yan Xiang
RSC Advances 2014 vol. 4(Issue 51) pp:26940-26945
Publication Date(Web):02 May 2014
DOI:10.1039/C4RA02869D
Carbon black supported amorphous Ni–B alloy catalyst (Ni–B/C) was prepared by a simple chemical reduction method and applied as an anode catalyst for direct hydrazine fuel cells (DHFCs). The structure and morphology of the obtained Ni–B/C nano-particles (NPs) were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), inductively coupled plasma optical emission spectrometry (ICP-OES) and X-ray photoelectron spectroscopy (XPS). The results showed that Ni–B/C was in an amorphous state and the NPs were highly dispersed on the surface of carbon black. The electrocatalytic performance of amorphous Ni–B/C towards hydrazine electrooxidation was studied by cyclic voltammetry (CV), linear sweep voltammetry (LSV) and chronoamperometry (CA) methods using a rotating disk electrode (RDE) and compared with crystalline Ni/C NPs, where a two-fold increase in the catalytic current density towards hydrazine electrooxidation was observed.
Co-reporter:Shanfu Lu, Ruijie Xiu, Xin Xu, Dawei Liang, Haining Wang, Yan Xiang
Journal of Membrane Science 2014 464() pp: 1-7
Publication Date(Web):
DOI:10.1016/j.memsci.2014.03.053
Co-reporter:Jiangju Si;Dr. Shanfu Lu;Xin Xu;Sikan Peng;Ruijie Xiu; Yan Xiang
ChemSusChem 2014 Volume 7( Issue 12) pp:3389-3395
Publication Date(Web):
DOI:10.1002/cssc.201402664
Abstract
To reconcile the tradeoff between conductivity and dimensional stability in AEMs, a novel Gemini quaternary ammonium poly (ether ether ketone) (GQ-PEEK) membrane was designed and successfully synthesized by a green three-step procedure that included polycondensation, bromination, and quaternization. Gemini quaternary ammonium cation groups attached to the anti-swelling PEEK backbone improved the ionic conductivity of the membranes while undergoing only moderate swelling. The grafting degree (GD) of the GQ-PEEK significantly affected the properties of the membranes, including their ion-exchange capacity, water uptake, swelling, and ionic conductivity. Our GQ-PEEK membranes exhibited less swelling (≤40 % at 25–70 °C, GD 67 %) and greater ionic conductivity (44.8 mS cm−1 at 75 °C, GD 67 %) compared with single quaternary ammonium poly (ether ether ketone). Enhanced fuel cell performance was achieved when the GQ-PEEK membranes were incorporated into H2/O2 single cells.
Co-reporter:Dr. Siyuan Rao;Dr. Ruijie Xiu;Dr. Jiangju Si; Shanfu Lu;Dr. Meng Yang; Yan Xiang
ChemSusChem 2014 Volume 7( Issue 3) pp:822-828
Publication Date(Web):
DOI:10.1002/cssc.201301060
Abstract
In situ synthesis is a powerful approach to control nanoparticle formation and consequently confers extraordinary properties upon composite membranes relative to conventional doping methods. Herein, uniform nanoparticles of cesium hydrogen salts of phosphotungstic acid (CsPW) are controllably synthesized in situ in Nafion to form CsPW–Nafion nanocomposite membranes with both improved proton conductivity and methanol-crossover suppression. A 101.3 % increase of maximum power density has been achieved relative to pristine Nafion in a direct methanol fuel cell (DMFC), indicating a potential pathway for large-scale fabrication of DMFC alternative membranes.
Co-reporter:Fei Lan, Deli Wang, Shanfu Lu, Jin Zhang, Dawei Liang, Sikan Peng, Yanyan Liu and Yan Xiang
Journal of Materials Chemistry A 2013 vol. 1(Issue 5) pp:1548-1552
Publication Date(Web):12 Dec 2012
DOI:10.1039/C2TA00458E
Novel Pd based coral-like nanochain networks decorated with ultra-low loading (0.66 at%) Pt (Pt-on-PdCNNs) were successfully synthesized through a facile wet chemical method. The Pt-on-PdCNNs exhibited significantly enhanced activity and stability towards formic acid electrooxidation, which was ascribed to their unique properties such as the highly interconnected networks, the more exposed Pd(111) planes and the reduced CO formation and adsorption on the Pt–Pd surface.
Co-reporter:Sikan Peng, Shanfu Lu, Jin Zhang, Pang-Chieh Sui and Yan Xiang
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 27) pp:11217-11220
Publication Date(Web):24 May 2013
DOI:10.1039/C3CP52150H
A reaction kinetic model of the bipolar membrane interface in the bipolar membrane fuel cell (BPMFC) was proposed based on the p–n junction theory and chemical reaction kinetics. It verified the self-humidification feasibility of the BPMFC successfully.
Co-reporter:Siyuan Rao, Zhibin Guo, Dawei Liang, Deliang Chen, Yen Wei and Yan Xiang
Physical Chemistry Chemical Physics 2013 vol. 15(Issue 38) pp:15821-15824
Publication Date(Web):05 Aug 2013
DOI:10.1039/C3CP52894D
The biohybrid sensor is an emerging technique for multi-functional detection that utilizes the instinctive responses or interactions of biomolecules. We develop a biohybrid pH sensor by taking advantage of the pH-dependent photoelectric characteristics of proteorhodopsin (pR). The transient absorption kinetics study indicates that the photoelectric behavior of pR is attributed to the varying lifetime of the M intermediate at different environmental pH values. This pR-based biohybrid light-powering sensor with microfluidic design can achieve real-time pH detection with quick response and high sensitivity. The results of this work would shed light on pR and its potential applications.
Co-reporter:Yan Xiang, Shanfu Lu and San Ping Jiang
Chemical Society Reviews 2012 vol. 41(Issue 21) pp:7291-7321
Publication Date(Web):04 Sep 2012
DOI:10.1039/C2CS35048C
As one of the most effective synthesis tools, layer-by-layer (LbL) self-assembly technology can provide a strong non-covalent integration and accurate assembly between homo- or hetero-phase compounds or oppositely charged polyelectrolytes, resulting in highly-ordered nanoscale structures or patterns with excellent functionalities and activities. It has been widely used in the developments of novel materials and nanostructures or patterns from nanotechnologies to medical fields. However, the application of LbL self-assembly in the development of highly efficient electrocatalysts, specific functionalized membranes for proton exchange membrane fuel cells (PEMFCs) and electrode materials for supercapacitors is a relatively new phenomenon. In this review, the application of LbL self-assembly in the development and synthesis of key materials of PEMFCs including polyelectrolyte multilayered proton-exchange membranes, methanol-blocking Nafion membranes, highly uniform and efficient Pt-based electrocatalysts, self-assembled polyelectrolyte functionalized carbon nanotubes (CNTs) and graphenes will be reviewed. The application of LbL self-assembly for the development of multilayer nanostructured materials for use in electrochemical supercapacitors will also be reviewed and discussed (250 references).
Co-reporter:Qi Zhang, Yan Xiang, Dawei Liang, Yinggui Peng, Hong Guo
Bioorganic & Medicinal Chemistry Letters 2012 Volume 22(Issue 4) pp:1814-1817
Publication Date(Web):15 February 2012
DOI:10.1016/j.bmcl.2011.11.028
N-[(2-Hydroxy-3-trimethylammonium) propyl] chitosan chloride (HTACC) was prepared to construct a chitosan-based zinc complex (HTACC–Zn(II)) as a catalyst with good water solubility for rapid DNA cleavage. Results indicated that the observed rate constant (kobs) of plasmid DNA cleaved by HTACC–Zn(II) could be enhanced by 107-fold compared with that of uncatalyzed DNA cleavage. The kinetic behavior of HTACC–Zn(II) for DNA cleavage is well fitted by Michaelis–Menten model. The results of gel electrophoresis suggested that HTACC–Zn(II) preferentially perform double-strand break of plasmid DNA.The chitosan-based artificial hydrolase, construct by quaternized-chitosan with zinc ions, could dedicate 107-fold catalytic efficiency for plasmid DNA cleavage with preferentially double-strand cleavage under 1 μM concentration.
Co-reporter:Qinggang Meng;Shanfu Lu;Sunhui Lu
Journal of Sol-Gel Science and Technology 2012 Volume 63( Issue 1) pp:1-7
Publication Date(Web):2012 July
DOI:10.1007/s10971-012-2732-8
Fine powders of p-type CuCr1−xMgxO2 (0 ≤ x ≤ 0.15) with improved thermoelectric properties were synthesized by sol–gel method through nitrate-citrate route. The sintered CuCr1−xMgxO2 (0 ≤ x ≤ 0.15) bulk contained the CuCr1−xMgxO2 phase with a rhombohedral structure, R3 m, along with trace second phase CuO, MgCr2O4. With the doping amount of Mg increasing, the grain size enlarged with oppositely decreased of the porosity. The substitution of Mg could give four orders improvement on electrical conductivity up to 10.34 S/cm at room temperature compared with the undoped samples. The positive Seebeck coefficients of doping oxides implied the typical p-type conducting oxides obtained by sol–gel method. The highest value of power factor has been achieved to be 1.37 × 10−4 Wm−1 K−2 for CuCr0.90Mg0.10O2 at 470 K. As a conclusion, we realized that the sol–gel method is a very effective and feasible shortcut on transparent oxide synthesis with desirable thermoelectric properties.
Co-reporter:Yan Xiang, Meng Yang, Jin Zhang, Fei Lan, Shanfu Lu
Journal of Membrane Science 2011 Volume 368(1–2) pp:241-245
Publication Date(Web):15 February 2011
DOI:10.1016/j.memsci.2010.11.049
In the present study, a novel composite methanol-blocking polymer electrolyte membrane was prepared by anchoring water-soluble phosphotungstic acid (HPW) in bulk phase of Nafion through interactions between HPW and Cs+ ions. Results of morphology and elemental mapping analysis indicated that this composite membrane had a dense structure with uniformly distributed Cs–HPW clusters. The composite membrane exhibited a rather low methanol diffusion coefficient (P, 0.97 × 10−6 cm2 s−1) and also the comparable conductivity (σ, 3.6 × 10−2 S cm−1) contrast with pristine Nafion (σ, 5.1 × 10−2 S cm−1). The selective factor (σ/P) of the composite membrane was six times higher than that of pristine Nafion. Single cell performance results showed that the maximum power density increased by 26% over the cell performance of pristine Nafion under the same conditions.Research highlights▶ Water-soluble phosphotungstic acid was successfully anchored in the bulk phase of Nafion. ▶ The Cs–HPW cluster in the composite membrane exhibited excellent stability including methanol-blocking and conductivity. ▶ Cs–HPW–Nafion membrane showed a much higher performance in methanol-blocking and cell output.
Co-reporter:Yan Xiang, Jin Zhang, Yang Liu, Zhibin Guo, Shanfu Lu
Journal of Membrane Science 2011 Volume 367(1–2) pp:325-331
Publication Date(Web):1 February 2011
DOI:10.1016/j.memsci.2010.11.013
In this study, purple membrane (PM) was applied as a methanol-blocking agent on Nafion® membranes. A series of well-organized poly(diallyldimethylammonium chloride)/PM multilayer films were obtained on a Nafion® 212 surface (PDDA/PM/Nafion®) to form composite membranes by the electrostatic layer-by-layer (LbL) self-assembly method. The effect of the PDDA/PM/Nafion® heterogenic interface on proton conductivity and methanol permeability was studied by alternating the deposited surface. With five PDDA/PM bilayers, double-sided modification (PDDA/PM)DF-5 and single-side modification (PDDA/PM)SF-5 resulted in excellent methanol blocking with a 73.4% and 64.7% reduction in methanol permeability in comparison with unmodified Nafion® 212, respectively. Indeed, the involvement of PM suppressed the methanol crossover. With regard to the selectivity factor (PDDA/PM)DF-1 composite membranes showed approximately 2-fold improvement as compared with unmodified Nafion® membranes. The cell performance of (PDDA/PM)SF-1 composite membranes achieved a power density of 27.0 mW cm−2 which is 48.4% increase compared to cells using unmodified Nafion® 212 membranes. Moreover, with (PDDA/PM)DF-1, we achieved a power density of 34.4 mW cm−2. This study highlights the potential application of PM as multifunctional protein membrane in direct methanol fuel cells.Research highlights▶ PM, a very promising biomaterial, was used as a methanol-blocking agent in DMFCs. ▶ The effect of the PDDA/PM/Nafion® heterogenic interface on proton conductivity and methanol permeability was studied by alternating the deposited surface. ▶ 2 sides of the PDDA/PM multilayers on the substrate have different methanol permeabilities. ▶ The Nafion-based composite membranes exhibit a low methanol permeability and high fuel cell performance.
Co-reporter:Qi Zhang;Ruxin Yang;Jiangju Si;Hong Guo
Chinese Journal of Chemistry 2011 Volume 29( Issue 4) pp:711-718
Publication Date(Web):
DOI:10.1002/cjoc.201190145
Abstract
We aimed to explore the role of chitosan-based metal complexes in catalyzing the hydrolysis of phosphodiesters. To this end, we performed detailed studies on the kinetics of the chitosan copper complex (CSCu)-catalyzed hydrolysis of bis(4-nitrophenol) phosphate (BNPP) in Tris-H+ buffer and in an organic solvent. A significant enhancement in the rate of reaction (up to 3×105-fold acceleration) was observed at pH 8.0 (25°C). The pH dependence of BNPP hydrolysis at pH 5.5–9.5 and the UV spectra revealed that the copper-bounded water molecules underwent deprotonation to form the active catalytic species CSCu-OH. The kinetic behavior of BNPP catalytic hydrolysis in the Tris-H+ buffer was consistent with that predicted by the Michaelis-Menten kinetics model. An intramolecular nucleophilic attack by the copper-bonded hydroxide group on the same activated phosphodiester substrate was proposed as the catalytic mechanism for CSCu-catalyzed reaction system. The results of DNA binding and cleavage experiments indicated electrostatic binding mode of CSCu to DNA as well as the strong capability of CSCu to disturb the supercoiled strand of DNA and cleave it to nicked circular form.
Co-reporter:Tingting Zhao;Ruxin Yang;Chen Zhong;Yan Li
Journal of Materials Science 2011 Volume 46( Issue 8) pp:2529-2535
Publication Date(Web):2011 April
DOI:10.1007/s10853-010-5104-1
Titanium–nickel (TiNi) shape memory alloy is modified with tantalum (Ta) plasma immersion ion implantation (PIII). Scanning electron microscope (SEM), atomic force microscopy (AFM), inductively coupled plasma mass spectrometry (ICP-MS), methyl-thiazol-tetrazolium (MTT), and cell culture are adopted to evaluate the surface morphology, roughness, Ni release, in vitro cytotoxicity, and cell behavior of TiNi and Ta-implanted TiNi (Ta–TiNi) alloys. Results showed that the surface became rougher and was covered by ordered and uniform grains after Ta implantation. Ni release was averagely inhibited by Ta–TiNi to up to 60% of that in unmodified TiNi alloy within 30 days. MTT assays demonstrated that Ta–TiNi sample allowed greater degree of cell proliferation for both smooth muscle cell and osteoblasts, indicating excellent protection and cyto-compatibility. A negative correlation was observed between Ni release and cell proliferation. Analysis of the cell morphology revealed healthy cells extending on the alloy surface, which indicated that TiNi alloy had good cyto-compatibility despite the initial Ni dissolution, but the implanted Ta would endow traditional TiNi alloy much lower Ni release, improved cyto-compatibility and other potential merits.
Co-reporter:Jin Zhang, Fei Lan, Dawei Liang, Yanxin Xiao, Shanfu Lu, Yan Xiang
Journal of Membrane Science 2011 382(1–2) pp: 350-354
Publication Date(Web):
DOI:10.1016/j.memsci.2011.08.039
Co-reporter:Meng Yang, Shanfu Lu, Jinlin Lu, San Ping Jiang and Yan Xiang
Chemical Communications 2010 vol. 46(Issue 9) pp:1434-1436
Publication Date(Web):22 Jan 2010
DOI:10.1039/B912779H
A novel PDDA/PWA–Nafion composite electrolyte membrane with enhanced proton conductivity (σ) to methanol permeability (P) ratio, σ/P, was fabricated by layer-by-layer self-assembly of negatively charged water soluble PWA and positively charged polyelectrolyte PDDA.
Co-reporter:Yan Xiang, Qi Zhang, Jiangju Si, Jianping Du, Hong Guo, Tao Zhang
Journal of Molecular Catalysis A: Chemical 2010 322(1–2) pp: 33-38
Publication Date(Web):
DOI:10.1016/j.molcata.2010.02.011
Co-reporter:Yan Xiang, Meng Yang, Zhibin Guo, Zheng Cui
Journal of Membrane Science 2009 Volume 337(1–2) pp:318-323
Publication Date(Web):15 July 2009
DOI:10.1016/j.memsci.2009.04.006
A series of blending chitosan sulfate membranes have been developed by grafting the chitosan monomers with sulfonic groups, then cross-linking the polymers from the bond reactions between the sulfonic groups in the chitosan sulfate and the amido groups in the pure chitosan monomers. Mechanical characterizations demonstrated that the dimensional swelling as well as the methanol crossover of the chitosan membranes were suppressed successfully by the polymer blending, with area swelling value decreased from 55.1% to 39.3% and methanol diffusion coefficient decreased from 1.0 × 10−6 cm2 s−1 of pure chitosan to 4.7 × 10−7 cm2 s−1 of the membrane with chitosan sulfate content of ∼9.1 wt% (CCSM 110). The thermal analysis indicated that the blending chitosan sulfate membranes were structure stable below 100 °C. The blending membrane showed the best conductivity (0.03 S cm−1 at 80 °C). The methanol permeability of CCSM 110 was much lower compared with that of Nafion 112 (1.9 × 10−6 cm2 s−1).
Co-reporter:San Ping Jiang, Lan Zhang, Hong Quan He, Rong Keng Yap, Yan Xiang
Journal of Power Sources 2009 Volume 189(Issue 2) pp:972-981
Publication Date(Web):15 April 2009
DOI:10.1016/j.jpowsour.2008.12.064
Lanthanum silicate oxyapatite, La10Si6O27 is successfully synthesized by a water-based gel-casting technique. The effect of calcination and sintering temperatures on the conductivity is investigated in detail in the temperature range between 300 and 800 °C by the impedance spectroscopy. The highest oxygen ion conductivity is 1.50 × 10−3 S cm−1 at 500 °C and 3.46 × 10−2 S cm−1 at 800 °C for an apatite electrolyte sintered at 1650 °C, which is one order of magnitude higher than that synthesized by the conventional solid state reaction route under the same sintering conditions. The thermal expansion coefficient (TEC) of the as-synthesized apatite is 9.7 × 10−6 K−1. A solid oxide fuel cell using La10Si6O27 as an electrolyte shows an open circuit potential of 1.06 V and power output of 7.89 mW cm−2 at 800 °C. The results demonstrate the potential of the silicate oxyapatite materials synthesized by the gel-casting as an alternative electrolyte in solid oxide fuel cells.
Co-reporter:Yuan Deng, Yan Xiang and Yuanzeng Song
Crystal Growth & Design 2009 Volume 9(Issue 7) pp:3079
Publication Date(Web):May 12, 2009
DOI:10.1021/cg800808u
Bi2Te3 thin films, composed of ordered nanowire arrays, have been successfully fabricated by a convenient physical vapor deposition method without using any template. The composition and microstructure of these films were determined by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), and high resolution transmission electron microscopy (HRTEM). The effects of deposition rate, substrate temperature, and deposition time on morphologies of Bi2Te3 films were investigated. The effects of morphology of film on the electrical conductivity and Seebeck coefficient were also studied. The results show that the nanowire arrays are composed of single-crystalline Bi2Te3 nanowires with diameters of about 18 nm. The nanowires are parallel to each other and uniformly distributed. The film of nanowire arrays shows good transport properties. The growth mechanism of such nanostructure was proposed.
Co-reporter:Lan Zhang, Xinbing Chen, San Ping Jiang, Hong Quan He, Yan Xiang
Solid State Ionics 2009 Volume 180(17–19) pp:1076-1082
Publication Date(Web):16 July 2009
DOI:10.1016/j.ssi.2009.05.010
Doped lanthanum manganese chromite based perovskite, La0.7A0.3Cr0.5Mn0.5O3 − δ (LACM, A = Ca, Sr, Ba), on yttria-stabilized zirconia (YSZ) electrolyte is investigated as potential electrode materials for solid oxide fuel cells (SOFCs). The electrical conductivity and electrochemical activity of LACM depend on the A-site dopant. The best electrochemical activity is obtained on the La0.7Ca0.3Cr0.5Mn0.5O3 − δ/YSZ (LCCM/YSZ) composite electrodes. The conductivity of LCCM is 29.9 S cm− 1 at 800 °C in air, and the electrode polarization resistance (RE) of the LCCM/YSZ composite cathode for the O2 reduction reaction is 0.5 Ω cm2 at 900 °C. The effect of Gd-doped ceria (GDC) impregnation on the LCCM cathode polarization resistances is also studied. GDC impregnation significantly enhances the electrochemical activity of the LCCM cathode. In the case of the 6.02 mg cm− 2 GDC-impregnated LCCM cathode, RE is 0.4 Ω cm2 at 800 °C, ~ 60 times smaller than 24.4 Ω cm2 measured on a LCCM cathode without the GDC impregnation. Finally the electrochemical activities of the doped lanthanum manganese chromites for the H2 oxidation reaction are also investigated.
Co-reporter:Yan Xiang, Meng Yang, Tao Su, Yuanyuan Chen, Lijun Bi and Kunsheng Hu
The Journal of Physical Chemistry B 2009 Volume 113(Issue 22) pp:7762-7766
Publication Date(Web):May 12, 2009
DOI:10.1021/jp901416j
In this study, labeled purple membrane (PM, Halobacterium salinarium) patches with maintained bioactivity were prepared by biotinylation of the glycolipids on the extracellular (EC) surface of the PM. After in situ streptavidin incubation, the extracellular surface could be directly visualized because it was completely covered with bright dots. The height of a single biotin/streptavidin interaction layer was approximately 2.5 nm. By using calcium thioglycolate-modified tips and an atomic-force microscope (AFM), two distinct topographical features of PMs placed in a buffer with low salt concentration were recognized: the flat EC surface and the domelike cytoplasmic (CP) surface. Biotinylation and AFM with modified tips were simultaneously used with consistent results. Those observations are useful for future studies on PM bioconjugation and oriented assembly as well as the design of bacteriorhodopsin-based photoelectric devices.
Co-reporter:Yan Xiang;Jiangju Si;Qi Zhang;Yang Liu ;Hong Guo
Journal of Polymer Science Part A: Polymer Chemistry 2009 Volume 47( Issue 3) pp:
Publication Date(Web):
DOI:10.1002/pola.23211
Abstract
A novel series of artificial glycoprotein, peptide-chitosan copolymers with secondary structural side chain have been synthesized by ring-opening polymerization of L-tryptophan N-carboxyanhydride under homogeneous conditions. Their chemical structures and polymerization degree (DP) were characterized by IR, 13C NMR, and XRD spectra. Distinctly secondary protein structure has been found in the poly-L-tryptophan side chains of copolymers and with the lengthening of side chain (i.e., the increase of DP at the same time), its conformations could transfer from β-sheet to α-helix. The content of α-helix reaches about 41% when DP of polytryptophan is 22. The solubility of graft copolymers in polar solvent strongly depends on the length of poly-L-tryptophan side chains. Unique fluorescence emission at 360 nm has been observed in the glycopolymers and the intensity shows the positive-correlation with the increasing of DP of polytryptophan. Importantly, the fluorescence effect can be quenched easily by the coordination with copper ions which provides the possibility on the biosensor design. In comparison with chitosan, glycopolymers also present impressively enhanced compressive strength and elastic modules when it is blended with epoxy E 44 to form epoxy-copolymer hybrid resin. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 925–934, 2009
Co-reporter:Siyuan Rao, Zhibin Guo, Dawei Liang, Deliang Chen, Yen Wei and Yan Xiang
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 38) pp:NaN15824-15824
Publication Date(Web):2013/08/05
DOI:10.1039/C3CP52894D
The biohybrid sensor is an emerging technique for multi-functional detection that utilizes the instinctive responses or interactions of biomolecules. We develop a biohybrid pH sensor by taking advantage of the pH-dependent photoelectric characteristics of proteorhodopsin (pR). The transient absorption kinetics study indicates that the photoelectric behavior of pR is attributed to the varying lifetime of the M intermediate at different environmental pH values. This pR-based biohybrid light-powering sensor with microfluidic design can achieve real-time pH detection with quick response and high sensitivity. The results of this work would shed light on pR and its potential applications.
Co-reporter:Jiangju Si, Haining Wang, Shanfu Lu, Xin Xu, Sikan Peng and Yan Xiang
Journal of Materials Chemistry A 2017 - vol. 5(Issue 8) pp:NaN4010-4010
Publication Date(Web):2017/01/19
DOI:10.1039/C6TA09277B
To resolve the trade-off between conductivity and stability in anion-exchange membranes (AEMs), we proposed a strategy to modulate the membrane morphology from isolated ionic clusters to interconnected channels by precise adjustment of the amphiphilic architectures. From the perspective of AEM molecular designing, by synchronously increasing the amphiphilic segments, well-connected conductive nano-channels, comprising overlapped larger hydrophilic domains (35–40 nm), were constructed and validated by percolation theory. The whole synthesis process was green, avoiding the toxic chloromethyl methyl ether route. The unique molecular, spatial and micro-structures enabled the membranes to exhibit excellent performance. The connective hydrophilic channels significantly enhanced the conductivity, while the increasing hydrophobicity reduced the water uptake and swelling, improving the dimensional and chemical stability of the membranes. This strategy successfully solves the trade-off issue between conductivity and stability in AEMs.
Co-reporter:Yan Xiang, Shanfu Lu and San Ping Jiang
Chemical Society Reviews 2012 - vol. 41(Issue 21) pp:NaN7321-7321
Publication Date(Web):2012/09/04
DOI:10.1039/C2CS35048C
As one of the most effective synthesis tools, layer-by-layer (LbL) self-assembly technology can provide a strong non-covalent integration and accurate assembly between homo- or hetero-phase compounds or oppositely charged polyelectrolytes, resulting in highly-ordered nanoscale structures or patterns with excellent functionalities and activities. It has been widely used in the developments of novel materials and nanostructures or patterns from nanotechnologies to medical fields. However, the application of LbL self-assembly in the development of highly efficient electrocatalysts, specific functionalized membranes for proton exchange membrane fuel cells (PEMFCs) and electrode materials for supercapacitors is a relatively new phenomenon. In this review, the application of LbL self-assembly in the development and synthesis of key materials of PEMFCs including polyelectrolyte multilayered proton-exchange membranes, methanol-blocking Nafion membranes, highly uniform and efficient Pt-based electrocatalysts, self-assembled polyelectrolyte functionalized carbon nanotubes (CNTs) and graphenes will be reviewed. The application of LbL self-assembly for the development of multilayer nanostructured materials for use in electrochemical supercapacitors will also be reviewed and discussed (250 references).
Co-reporter:Chunxiao Wu, Shanfu Lu, Haining Wang, Xin Xu, Sikan Peng, Qinglong Tan and Yan Xiang
Journal of Materials Chemistry A 2016 - vol. 4(Issue 4) pp:NaN1179-1179
Publication Date(Web):2015/11/27
DOI:10.1039/C5TA08593D
A novel kind of effective vanadium ion-suppressed polysulfone–polyvinylpyrrolidone (PSF–PVP) membrane with high ion selectivity, superior stability and low cost is designed and constructed for vanadium redox flow batteries (VRFBs). The VRFB with the PSF–PVP–50 membrane exhibits impressive coulombic efficiency (98%) as well as energy efficiency (89%), and outstanding stability during the 2000 h continuous charge–discharge cycling test.
Co-reporter:Meng Yang, Shanfu Lu, Jinlin Lu, San Ping Jiang and Yan Xiang
Chemical Communications 2010 - vol. 46(Issue 9) pp:NaN1436-1436
Publication Date(Web):2010/01/22
DOI:10.1039/B912779H
A novel PDDA/PWA–Nafion composite electrolyte membrane with enhanced proton conductivity (σ) to methanol permeability (P) ratio, σ/P, was fabricated by layer-by-layer self-assembly of negatively charged water soluble PWA and positively charged polyelectrolyte PDDA.
Co-reporter:Sikan Peng, Shanfu Lu, Jin Zhang, Pang-Chieh Sui and Yan Xiang
Physical Chemistry Chemical Physics 2013 - vol. 15(Issue 27) pp:NaN11220-11220
Publication Date(Web):2013/05/24
DOI:10.1039/C3CP52150H
A reaction kinetic model of the bipolar membrane interface in the bipolar membrane fuel cell (BPMFC) was proposed based on the p–n junction theory and chemical reaction kinetics. It verified the self-humidification feasibility of the BPMFC successfully.
Co-reporter:Fei Lan, Deli Wang, Shanfu Lu, Jin Zhang, Dawei Liang, Sikan Peng, Yanyan Liu and Yan Xiang
Journal of Materials Chemistry A 2013 - vol. 1(Issue 5) pp:NaN1552-1552
Publication Date(Web):2012/12/12
DOI:10.1039/C2TA00458E
Novel Pd based coral-like nanochain networks decorated with ultra-low loading (0.66 at%) Pt (Pt-on-PdCNNs) were successfully synthesized through a facile wet chemical method. The Pt-on-PdCNNs exhibited significantly enhanced activity and stability towards formic acid electrooxidation, which was ascribed to their unique properties such as the highly interconnected networks, the more exposed Pd(111) planes and the reduced CO formation and adsorption on the Pt–Pd surface.
Co-reporter:Zhibin Guo, Ruijie Xiu, Shanfu Lu, Xin Xu, Shichun Yang and Yan Xiang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 16) pp:NaN8854-8854
Publication Date(Web):2015/03/13
DOI:10.1039/C5TA00415B
A submicro-pore containing proton exchange membrane (PEM) consisting of poly(ether sulfones) (PES) and polyvinylpyrrolidone (PVP) was successfully prepared through a scalable polymer blending method with monodispersed SiO2 solid spheres as a hard template. After doping with phosphoric acid (PA), an outstanding balance between proton conductivity and mechanical strength in these blends is obtained. The tensile strength of all the porous PES/PVP membranes ranges from 5.98 to 3.69 MPa with an increasing content of SiO2 from 10 wt% to 50 wt%, which satisfies the mechanical requirements of high-temperature proton exchange membrane fuel cells (PEMFCs). A proton conductivity of 0.09 S cm−1 is obtained for the as prepared composite membrane with a PA doping level of 350 wt% at 180 °C under anhydrous conditions, comparable with the state-of-the-art PBI/PA membranes. The mechanism for the “balanced” properties is that after the PA doping treatment, the mechanical strength satisfies the requirements of high-temperature PEMFCs with a decreased content of PVP at 50 wt%, while the proton conductivity is improved under the cooperative proton transfers both along the “bonded acid” caged inside the pores and the PA-rich domain formed by “free acid” in the submicro-pores. Furthermore, the PEM fuel cell with PA doped porous PES/PVP exhibits a power density of 454 mW cm−2 at 180 °C H2/O2 without external humidification. A fuel cell performance of ∼520 mV at 0.2 A cm−2 is maintained for 150 h without obviously decreasing. The submicro-pore containing PES/PVP blends allowed for a higher PA doping level, and consequently, enhanced proton conductivity, as well as improved mechanical strength and cell performance, showing potential for use as an alternative high-temperature PEM for fuel cells under anhydrous conditions.
Co-reporter:Haining Wang, Shanfu Lu, Yiwen Zhang, Fei Lan, Xin Lu and Yan Xiang
Journal of Materials Chemistry A 2015 - vol. 3(Issue 12) pp:NaN6285-6285
Publication Date(Web):2015/02/17
DOI:10.1039/C5TA00359H
THF was investigated as a suitable solvent to disperse pristine graphene due to the van der Waals interaction. THF was therefore chosen as the solvent to successfully synthesize Pd particles with a diameter of 1.8 nm on graphene which exhibited improved electrocatalytic activities and stabilities for formic acid electro-oxidation.
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