Carbon nanotubes （CNTs） supported Pt-Ru and Pt-Ru-Ni catalysts were prepared by chemical reduction of metal precursors with sodium borohydride at room temperature. The crystallographic properties and composition of ...Carbon nanotubes （CNTs） supported Pt-Ru and Pt-Ru-Ni catalysts were prepared by chemical reduction of metal precursors with sodium borohydride at room temperature. The crystallographic properties and composition of the catalysts were characterized by X-ray diffraction （XRD） and energy dispersive X-ray （EDX） analysis, and the catalytic activity and stability for methanol electro-oxidation were measured by electrochemical impedance spectroscopy （EIS）, linear sweep voltammetries （LSV）, and chronoamperometry （CA）. The results show that the catalysts exhibit face-centered cubic （fcc） structure. The particle size of Pt-Ru-Ni/CNTs catalyst is about 4.8 nm. The catalytic activity and stability of the Pt-Ru-Ni/CNTs catalyst are higher than those of Pt-Ru/CNTs catalyst.展开更多
Nanocrystalline tungsten carbide thin films were fabricated on graphite substrates by plasma enhanced chemical vapor deposition （PECVD） at H2 and Ar atmosphere, using WF6 and CH4 as precursors. The crystal phase, st...Nanocrystalline tungsten carbide thin films were fabricated on graphite substrates by plasma enhanced chemical vapor deposition （PECVD） at H2 and Ar atmosphere, using WF6 and CH4 as precursors. The crystal phase, structure and chemical components of the films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and energy-dispersive spectrometer （EDS）, respectively. The results show that the film prepared at CH4/WF6 concentration ratio of 20 and at 800℃ is composed of spherical particles with a diameter of 20-35 nm. Electrochemical investigations show that the electrochemical real surface area of electrode of the film is large, and the electrode of the film exhibits higher electro-catalytic activity in the reaction of methanol oxidation. The designated constant current of the film catalyst is 123.6 mA/cm^2 in the mixture solution of H2SO4 and CH3OH at the concentration of 0.5 and 2.0 mol/L at 70℃, and the designated constant potential is only 0.306 V （vs SCE）.展开更多
Pt：Pd：Co ternary alloy nanoparticles were synthesized by sodium borohydride reduction under nitrogen, and were supported on carbon black as catalysts for methanol and formic acid electro-oxidation. Compared with Pt0...Pt：Pd：Co ternary alloy nanoparticles were synthesized by sodium borohydride reduction under nitrogen, and were supported on carbon black as catalysts for methanol and formic acid electro-oxidation. Compared with Pt0.65C00.35/C, Pt/C, Pd0.65C00.35/C, and Pd/C catalyst, Pt0.35Pd0.35Co0.30/C exhibited relatively high durability and strong poisoning resistance, and the Pt-mass activity was 3.6 times higher than that of Pt/C in methanol oxidation reaction. Meanwhile, the Pt0.35Pd0.35Co0.30/C exhibited excellent activity with higher current density and higher CO tolerance than that of Pt0.6sCo0.35/C, Pt/C, Pd0.65C00.35/ C, and Pd/C in formic acid electro-oxidation.展开更多
A simple one-pot method was developed to prepare Pt Ni alloy nanoparticles,which can be self-decorated on multiwalled carbon nanotubes in [BMIm][BF4] ionic liquid.The nanohybrids are targeting stable nanocatalysts for...A simple one-pot method was developed to prepare Pt Ni alloy nanoparticles,which can be self-decorated on multiwalled carbon nanotubes in [BMIm][BF4] ionic liquid.The nanohybrids are targeting stable nanocatalysts for fuel cell applications.The sizes of the supported Pt Ni nanoparticles are uniform and as small as 1–2 nm.Pt-to-Ni ratio was controllable by simply selecting a Pt Ni alloy target.The alloy nanoparticles with Pt-to-Ni ratio of 1:1 show high catalytic activity and stability for methanol electro-oxidation.The performance is much higher compared with those of both Pt-only nanoparticles and commercial Pt/C catalyst.The electronic structure characterization on the Pt Ni nanoparticles demonstrates that the electrons are transferred from Ni to Pt,which can suppress the CO poisoning effect.展开更多
Carbon nanotubes-Nafion （CNTs-Nation） composites were prepared by impregnated CNTs with Nation in ethanol solution and characterized by FT-IR. Pt-Ru catalysts supported on CNTs-Nafion composites were synthesized by ...Carbon nanotubes-Nafion （CNTs-Nation） composites were prepared by impregnated CNTs with Nation in ethanol solution and characterized by FT-IR. Pt-Ru catalysts supported on CNTs-Nafion composites were synthesized by microwave-assisted polyol process. The physical and electrochemical properties of the catalysts were characterized by X-ray diffraction （XRD）, transmission electron microscope （TEM）, CO stripping voltammetry, cyclic voltammetry （CV） and chronoamperometry （CA）. The results showed that the Nation incorporation in CNTs-Nation composites did not significantly alter the oxygen-containing groups on the CNTs surface. The Pt-Ru catalyst supported on CNTs-Nafion composites with 2 wt% Naton showed good dispersion and the best CO oxidation and methanol electro-oxidation activities.展开更多
Pd@Ru bimetallic nanoparticles deposited on carbon black electro-catalysts have been fabricated by microwave-assisted polyol reduction method and investigated for methanol electro-oxidation （MEO）. The structure and ...Pd@Ru bimetallic nanoparticles deposited on carbon black electro-catalysts have been fabricated by microwave-assisted polyol reduction method and investigated for methanol electro-oxidation （MEO）. The structure and electro-catalytic properties of the as-prepared catalysts were characterized by XRD, SEM, TEM and cyclic voltammetry （CV） techniques. The results showed that the introduction of Ru element （2-10 wt%） into Pd 20 wt%/C （hereafter, denoted as Pd/C） produced a series of core-shell structured binary catalysts. Pd@Ru 5 wt%/C （hereafter, denoted as Pd@Rus/C） catalyst displayed the highest catalytic activity towards MEO. And the mass activity of Pd@Ru5/C electrode catalyst at E = -0.038 V （vs. Hg/HgO） was 1.42 times higher than that of Pd/C electrode catalyst. In addition, the relationship between the catalytic stability for MEO on Pd@Ru/C catalysts and the value of dbp/dfp （the ratio of MEO peak current density in the negative scan and positive scan） were also investigated. The result demonstrated that Pd@Rus/C offering the smallest value of Jbp/Jfp displayed the best stable catalytic performance.展开更多
Ultrafine mesoporous tungsten carbide （WC） was prepared from as-synthesized mesoporous WC using high-energy ball milling treatment. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and nitrogen adsor...Ultrafine mesoporous tungsten carbide （WC） was prepared from as-synthesized mesoporous WC using high-energy ball milling treatment. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and nitrogen adsorption-desorption techniques were used to characterize the samples. Brunauer-Emmett-Teller （BET） surface areas of WC samples increased with the increasing ball milling time and kept constant at 10-11 mZog 1 for over 9 h. The electrocatalytic properties of methanol electro-oxidation at WC powder microelectrodes were investigated by cyclic voltammetry, chronoamperometry, and quasi-steady-state polarization techniques. The results reveal that ball-milled WC exhibits higher activity for methanol electro-oxidation than as-synthesized mesoporous WC. The suitability of ball-milled WC for methanol electro-oxidation is better than platinum （Pt） micro-disk, although the current peak is not as high as the Pt micro-disk. Moreover, increasing the methanol concentration and reaction temperature promotes methanol electro-oxidation on ultrafine mesoporous WC.展开更多
Alloying degree, particle size and the level of dispersion are the key structural parameters of Pt-Ru/C catalyst in fuel cells. Solvent（s） used in the preparation process can affect the particle size and alloying de...Alloying degree, particle size and the level of dispersion are the key structural parameters of Pt-Ru/C catalyst in fuel cells. Solvent（s） used in the preparation process can affect the particle size and alloying degree of the object substance, which lead to a great positive impact on its properties. In this work, three types of solvents and their mixtures were used in preparation of the Pt-Ru/C catalysts by chemical reduction of metal precursors with sodium borohydride at room temperature. The structure of the catalysts was characterized by X-ray diffraction （XRD） and Transmission electron microscopy （TEM）. The catalytic activity and stability for methanol electro-oxidation were studied by Cyclic Voltammetry （CV） and Chronoamperometry （CA）. Pt-Ru/C catalyst prepared in H2O or binary solvents of H2O and isopropanol had large particle size and low alloying degree leading to low catalytic activity and less stability in methanol electro-oxidation. When tetrahydrofuran was added to the above solvent systems, Pt-Ru/C catalyst prepared had smaller particle size and higher alloying degree which resulted in better catalytic activity, lower onset and peak potentials, compared with the above catalysts. Moreover, the catalyst prepared in ternary solvents of isopropanol, water and tetrahydrofuran had the smallest particle size, and the high alloying degree and the dispersion kept unchanged. Therefore, this kind of catalyst showed the highest catalytic activity and good stability for methanol electro-oxidation.展开更多
在多壁碳纳米管负载的Pt-RuOxHy样品中引入氧化钨(WOm),能有效抑制样品中水合氧化钌(RuOxHy)在酸性电解质溶液中的溶解.在扩展电势(-0.20～0.96 V vs SCE)的电化学预处理过程中,RuOxHy的溶解程度从Pt-RuOxHy中的70%降至Pt-RuOxHy-WOm中...在多壁碳纳米管负载的Pt-RuOxHy样品中引入氧化钨(WOm),能有效抑制样品中水合氧化钌(RuOxHy)在酸性电解质溶液中的溶解.在扩展电势(-0.20～0.96 V vs SCE)的电化学预处理过程中,RuOxHy的溶解程度从Pt-RuOxHy中的70%降至Pt-RuOxHy-WOm中的15%.计时电流曲线测试结果表明,与窄电势区间(-0.20～0.46 V vs SCE)预处理的钌物种没有流失的样品相比,经扩展电势区间预处理的Pt-RuOxHy-WOm样品上甲醇电氧化反应的活性没有下降,而Pt-RuOxHy样品的活性则下降50%.展开更多
PtSn2-SnO2/C nanocatalyst was prepared by co-reduction of Pt and Sn precursor at ca,15℃.The formation of PtSn2-SnO2 nanoparticle was determined by XRD,TEM and XPS characterization.This PtSn2-SnO2/C nanocatalyst exhib...PtSn2-SnO2/C nanocatalyst was prepared by co-reduction of Pt and Sn precursor at ca,15℃.The formation of PtSn2-SnO2 nanoparticle was determined by XRD,TEM and XPS characterization.This PtSn2-SnO2/C nanocatalyst exhibits stronger resistance to CO poisoning and effectively improves methanol electro-catalytic effect,up to 3 times than the commercial Pt/C catalyst.展开更多
基金The project is supported by the National Natural Science Foundation of China (20576023)the Science and Technology Project of Guangzhou City (2005 J1-C0361)the Key Project of Education Bureau of Guangzhou City (2052).
文摘Carbon nanotubes （CNTs） supported Pt-Ru and Pt-Ru-Ni catalysts were prepared by chemical reduction of metal precursors with sodium borohydride at room temperature. The crystallographic properties and composition of the catalysts were characterized by X-ray diffraction （XRD） and energy dispersive X-ray （EDX） analysis, and the catalytic activity and stability for methanol electro-oxidation were measured by electrochemical impedance spectroscopy （EIS）, linear sweep voltammetries （LSV）, and chronoamperometry （CA）. The results show that the catalysts exhibit face-centered cubic （fcc） structure. The particle size of Pt-Ru-Ni/CNTs catalyst is about 4.8 nm. The catalytic activity and stability of the Pt-Ru-Ni/CNTs catalyst are higher than those of Pt-Ru/CNTs catalyst.
基金This work was supported by the National Natural Scmnce Foundation of China(Grant Nos.20276069,20476097)
文摘Nanocrystalline tungsten carbide thin films were fabricated on graphite substrates by plasma enhanced chemical vapor deposition （PECVD） at H2 and Ar atmosphere, using WF6 and CH4 as precursors. The crystal phase, structure and chemical components of the films were characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and energy-dispersive spectrometer （EDS）, respectively. The results show that the film prepared at CH4/WF6 concentration ratio of 20 and at 800℃ is composed of spherical particles with a diameter of 20-35 nm. Electrochemical investigations show that the electrochemical real surface area of electrode of the film is large, and the electrode of the film exhibits higher electro-catalytic activity in the reaction of methanol oxidation. The designated constant current of the film catalyst is 123.6 mA/cm^2 in the mixture solution of H2SO4 and CH3OH at the concentration of 0.5 and 2.0 mol/L at 70℃, and the designated constant potential is only 0.306 V （vs SCE）.
基金supported by NSFC(No.21373116)Tianjin Natural Science Research Fund(No.13JCYBJC18300)+1 种基金RFDP(No. 20120031110005)MOE Innovation Team of China(No. IRT13022)
文摘Pt：Pd：Co ternary alloy nanoparticles were synthesized by sodium borohydride reduction under nitrogen, and were supported on carbon black as catalysts for methanol and formic acid electro-oxidation. Compared with Pt0.65C00.35/C, Pt/C, Pd0.65C00.35/C, and Pd/C catalyst, Pt0.35Pd0.35Co0.30/C exhibited relatively high durability and strong poisoning resistance, and the Pt-mass activity was 3.6 times higher than that of Pt/C in methanol oxidation reaction. Meanwhile, the Pt0.35Pd0.35Co0.30/C exhibited excellent activity with higher current density and higher CO tolerance than that of Pt0.6sCo0.35/C, Pt/C, Pd0.65C00.35/ C, and Pd/C in formic acid electro-oxidation.
基金supported by the National Natural Science Foundation of China(No.61274019)the Soochow University-Western University Joint Centre for Synchrotron Radiation Research+1 种基金the Collaborative Innovation Center of Suzhou Nano Science & Technologythe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘A simple one-pot method was developed to prepare Pt Ni alloy nanoparticles,which can be self-decorated on multiwalled carbon nanotubes in [BMIm][BF4] ionic liquid.The nanohybrids are targeting stable nanocatalysts for fuel cell applications.The sizes of the supported Pt Ni nanoparticles are uniform and as small as 1–2 nm.Pt-to-Ni ratio was controllable by simply selecting a Pt Ni alloy target.The alloy nanoparticles with Pt-to-Ni ratio of 1:1 show high catalytic activity and stability for methanol electro-oxidation.The performance is much higher compared with those of both Pt-only nanoparticles and commercial Pt/C catalyst.The electronic structure characterization on the Pt Ni nanoparticles demonstrates that the electrons are transferred from Ni to Pt,which can suppress the CO poisoning effect.
基金supported by National Natural Science Foundation of China (NO.0576023)Key Project of Science and Technology Department of Guangdong Province (NO.2008B010800036 NO.2008B010800037)
文摘Carbon nanotubes-Nafion （CNTs-Nation） composites were prepared by impregnated CNTs with Nation in ethanol solution and characterized by FT-IR. Pt-Ru catalysts supported on CNTs-Nafion composites were synthesized by microwave-assisted polyol process. The physical and electrochemical properties of the catalysts were characterized by X-ray diffraction （XRD）, transmission electron microscope （TEM）, CO stripping voltammetry, cyclic voltammetry （CV） and chronoamperometry （CA）. The results showed that the Nation incorporation in CNTs-Nation composites did not significantly alter the oxygen-containing groups on the CNTs surface. The Pt-Ru catalyst supported on CNTs-Nafion composites with 2 wt% Naton showed good dispersion and the best CO oxidation and methanol electro-oxidation activities.
基金supported by the National Basic Research Program of China(2013CB934001)the Natural Science Foundation of Beijing(2051001)the Natural Science Foundation of China(51074011)
文摘Pd@Ru bimetallic nanoparticles deposited on carbon black electro-catalysts have been fabricated by microwave-assisted polyol reduction method and investigated for methanol electro-oxidation （MEO）. The structure and electro-catalytic properties of the as-prepared catalysts were characterized by XRD, SEM, TEM and cyclic voltammetry （CV） techniques. The results showed that the introduction of Ru element （2-10 wt%） into Pd 20 wt%/C （hereafter, denoted as Pd/C） produced a series of core-shell structured binary catalysts. Pd@Ru 5 wt%/C （hereafter, denoted as Pd@Rus/C） catalyst displayed the highest catalytic activity towards MEO. And the mass activity of Pd@Ru5/C electrode catalyst at E = -0.038 V （vs. Hg/HgO） was 1.42 times higher than that of Pd/C electrode catalyst. In addition, the relationship between the catalytic stability for MEO on Pd@Ru/C catalysts and the value of dbp/dfp （the ratio of MEO peak current density in the negative scan and positive scan） were also investigated. The result demonstrated that Pd@Rus/C offering the smallest value of Jbp/Jfp displayed the best stable catalytic performance.
基金Project supported by Science and Technology Major Project in International Cooperation of Zhejiang Province （No. 2008C14040）, Key Project of Natural Science Foundation of Zhejiang Province （No. Z4100790） and International Science ＆ Technology Cooperation Program of China （No. 2010DFB63680）.
文摘Ultrafine mesoporous tungsten carbide （WC） was prepared from as-synthesized mesoporous WC using high-energy ball milling treatment. X-ray diffraction （XRD）, scanning electron microscopy （SEM）, and nitrogen adsorption-desorption techniques were used to characterize the samples. Brunauer-Emmett-Teller （BET） surface areas of WC samples increased with the increasing ball milling time and kept constant at 10-11 mZog 1 for over 9 h. The electrocatalytic properties of methanol electro-oxidation at WC powder microelectrodes were investigated by cyclic voltammetry, chronoamperometry, and quasi-steady-state polarization techniques. The results reveal that ball-milled WC exhibits higher activity for methanol electro-oxidation than as-synthesized mesoporous WC. The suitability of ball-milled WC for methanol electro-oxidation is better than platinum （Pt） micro-disk, although the current peak is not as high as the Pt micro-disk. Moreover, increasing the methanol concentration and reaction temperature promotes methanol electro-oxidation on ultrafine mesoporous WC.
基金supported by 863 Project(No.2006AA05Z102)the Cultivation Fund of the Key Scientific and Technical Innovation Project,Ministry of Education of China (No.707050)+1 种基金Specialized Research Fund for the Doctoral Program of Higher Education (No.20060610023)Chengdu Natural Science Foundation (Nos.06GGYB449GX-030,and 07GGZD139GX)
文摘Alloying degree, particle size and the level of dispersion are the key structural parameters of Pt-Ru/C catalyst in fuel cells. Solvent（s） used in the preparation process can affect the particle size and alloying degree of the object substance, which lead to a great positive impact on its properties. In this work, three types of solvents and their mixtures were used in preparation of the Pt-Ru/C catalysts by chemical reduction of metal precursors with sodium borohydride at room temperature. The structure of the catalysts was characterized by X-ray diffraction （XRD） and Transmission electron microscopy （TEM）. The catalytic activity and stability for methanol electro-oxidation were studied by Cyclic Voltammetry （CV） and Chronoamperometry （CA）. Pt-Ru/C catalyst prepared in H2O or binary solvents of H2O and isopropanol had large particle size and low alloying degree leading to low catalytic activity and less stability in methanol electro-oxidation. When tetrahydrofuran was added to the above solvent systems, Pt-Ru/C catalyst prepared had smaller particle size and higher alloying degree which resulted in better catalytic activity, lower onset and peak potentials, compared with the above catalysts. Moreover, the catalyst prepared in ternary solvents of isopropanol, water and tetrahydrofuran had the smallest particle size, and the high alloying degree and the dispersion kept unchanged. Therefore, this kind of catalyst showed the highest catalytic activity and good stability for methanol electro-oxidation.
文摘在多壁碳纳米管负载的Pt-RuOxHy样品中引入氧化钨(WOm),能有效抑制样品中水合氧化钌(RuOxHy)在酸性电解质溶液中的溶解.在扩展电势(-0.20～0.96 V vs SCE)的电化学预处理过程中,RuOxHy的溶解程度从Pt-RuOxHy中的70%降至Pt-RuOxHy-WOm中的15%.计时电流曲线测试结果表明,与窄电势区间(-0.20～0.46 V vs SCE)预处理的钌物种没有流失的样品相比,经扩展电势区间预处理的Pt-RuOxHy-WOm样品上甲醇电氧化反应的活性没有下降,而Pt-RuOxHy样品的活性则下降50%.
基金supported by NSFC (Nos. 21373116 and 21421001)the Tianjin Natural Science Research Fund (No. 13JCYBJC18300)+1 种基金RFDP (No. 20120031110005)the MOE Innovation Team (No. IRT13022) of China
文摘PtSn2-SnO2/C nanocatalyst was prepared by co-reduction of Pt and Sn precursor at ca,15℃.The formation of PtSn2-SnO2 nanoparticle was determined by XRD,TEM and XPS characterization.This PtSn2-SnO2/C nanocatalyst exhibits stronger resistance to CO poisoning and effectively improves methanol electro-catalytic effect,up to 3 times than the commercial Pt/C catalyst.
