High performance cathode for polymer electrolyte membrane fuel cell was prepared by depositing Pt nanowires in a carbon matrix coated on a substrate, and using decal transfer method to fabricate the membrane electrode...High performance cathode for polymer electrolyte membrane fuel cell was prepared by depositing Pt nanowires in a carbon matrix coated on a substrate, and using decal transfer method to fabricate the membrane electrode assembly. The effects of carbon and ionomer contents on the electrode micro-structure and fuel cell performance are investigated by physical characterization and single cell testing. The Pt nanowires are gradient distributed across the cathode thickness, and more Pt exists near the membrane. Both the carbon and ionomer contents can affect the Pt nanowires distribution and aggregation. In addition, the carbon loading dominates the transport distance of gas and proton, and the ionomer content affects the triple phase boundaries and porosity in the cathode. The optimal structure of Pt nanowire cathode is obtained at 0.10 mg·cm^-2 carbon loading and 10 wt% ionomer.展开更多
A Pt-nanooarticle/carbon nanotube modified graphite electrode immobilized with cholesterol oxidase/sol＇-gel layer was developed for monitoring cholesterol.Using this electrode,cholesterol concentration（4.0×10^-...A Pt-nanooarticle/carbon nanotube modified graphite electrode immobilized with cholesterol oxidase/sol＇-gel layer was developed for monitoring cholesterol.Using this electrode,cholesterol concentration（4.0×10^-6 tp 1.0×10^-4mol/L）could be determined accurately in the presence of ascorbic or uric acid,and the response time was rapid （〈 20 s）. This biosensor has high sensitivity and selectivity.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
Mesoporous carbon（MC） with surface area of 380 m^2/g was prepared and employed as the carbon support of Pt catalyst for counter electrode of dye-sensitized solar cells.Pt/MC samples containing 1 wt%Pt were prepared ...Mesoporous carbon（MC） with surface area of 380 m^2/g was prepared and employed as the carbon support of Pt catalyst for counter electrode of dye-sensitized solar cells.Pt/MC samples containing 1 wt%Pt were prepared by reducing chloroplatinic acid on MC using wet impregnation.It was found that Pt nanoparticles were uniform in size and highly dispersed on MC supports.The average size of Pt nanoparticles is about 3.4 nm.Pt/MC electrodes were fabricated by coating Pt/MC samples on fluorine-doped tin oxide glass.The overall conversion efficiency of dye-sensitized solar cells with Pt/MC counter electrode is 6.62%,which is higher than that of the cells with conventional Pt counter electrode in the same conditions.展开更多
In order to study the properties of supporting Pt catalysts for methanol oxidation,carbon-nanotubes are used by electrochemical deposition method. Different deposition turns,different cyclic voltammetry scanning speed...In order to study the properties of supporting Pt catalysts for methanol oxidation,carbon-nanotubes are used by electrochemical deposition method. Different deposition turns,different cyclic voltammetry scanning speeds and processing time with ascorbic acid are investigated in this paper. The micrographs of Pt / CNTs catalysts are characterized by scanning electron microscopy,the electro-catalytic properties of Pt / CNTs catalysts for methanol oxidation are investigated by cycle voltammetry and chronoamperometry. The results show that the size of platinum will be greater with the faster scanning speed. After dissolution in ascorbic acid,Pt nanoparticles disperse uniformly. The obtained Pt / CNTs catalysts show a high electro-catalytic activity and stability.展开更多
It is reported that the highly dispersed Pt nanoparticles on carbon nanotubes can be synthesized under mild conditions by in situ plasma treatment.The carbon nanotube was pretreated by O_2 plasma to transform into oxi...It is reported that the highly dispersed Pt nanoparticles on carbon nanotubes can be synthesized under mild conditions by in situ plasma treatment.The carbon nanotube was pretreated by O_2 plasma to transform into oxide carbon nanotubes（O-CNTs）,and then it was mixed with the precursors（the mixture of H_2 PtCl_6and PdCl_6）.After that,the O-CNTs and the precursors were simultaneously treated by H_2 plasma.The precursors were transformed into Pt-Pd nanoparticles（NPs）and the O-CNTs transformed into CNT.The synthesized CNT-based Pt-Pd nanoparticles were characterized by scanning electron microscopy,transmission electron microscopy,X-ray diffraction and X-ray photoelectron spectroscopy.All the analysis showed that the Pt-Pd nanoparticles were deposited on CNT as a form of face-centered cubical structure.展开更多
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
As a rapid uniform and efficient heating method, microwave irradiation has been widely used in chemical reaction and preparing nanomaterials. Here Pt/carbon nanotube(CNT) catalysts with w(Pt)=18.1% and 9.4 % were rapi...As a rapid uniform and efficient heating method, microwave irradiation has been widely used in chemical reaction and preparing nanomaterials. Here Pt/carbon nanotube(CNT) catalysts with w(Pt)=18.1% and 9.4 % were rapidly synthesized by microwave irradiation heating polyol process and employing the ethylene glycol solution of H 2PtCl 6 as the precursors in the presence of CNT support. TEM imaging showed that microwave-prepared Pt nanoparticles were very uniform in size, with an average size of 3.1 nm, and uniformly dispersed on the CNT surface. Electrochemical experiments demonstrated that microwave-synthesized Pt/CNT catalysts exhibited a higher catalytic activity for electrooxidation of liquid methanol than E-TEK Pt/C. The significant improvement in catalyst performance derives from that microwave-synthesized Pt nanoparticles have a uniform small particle size and uniforml dispersion on the CNT surface.展开更多
文摘High performance cathode for polymer electrolyte membrane fuel cell was prepared by depositing Pt nanowires in a carbon matrix coated on a substrate, and using decal transfer method to fabricate the membrane electrode assembly. The effects of carbon and ionomer contents on the electrode micro-structure and fuel cell performance are investigated by physical characterization and single cell testing. The Pt nanowires are gradient distributed across the cathode thickness, and more Pt exists near the membrane. Both the carbon and ionomer contents can affect the Pt nanowires distribution and aggregation. In addition, the carbon loading dominates the transport distance of gas and proton, and the ionomer content affects the triple phase boundaries and porosity in the cathode. The optimal structure of Pt nanowire cathode is obtained at 0.10 mg·cm^-2 carbon loading and 10 wt% ionomer.
基金The project is supported by the National Natural Science Foundation of China(29975024,202750-34)Key Project of Science and Technology of Zhejiang Province(2003C21024).The authors acknowledge the Instrumental Analysis Center of Zhejiang University for special measurements.
文摘A Pt-nanooarticle/carbon nanotube modified graphite electrode immobilized with cholesterol oxidase/sol＇-gel layer was developed for monitoring cholesterol.Using this electrode,cholesterol concentration（4.0×10^-6 tp 1.0×10^-4mol/L）could be determined accurately in the presence of ascorbic or uric acid,and the response time was rapid （〈 20 s）. This biosensor has high sensitivity and selectivity.
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.
文摘质子交换膜燃料电池(PEMFCs)因其高能量密度、低操作温度和环保等特性,被视为极具潜力的能量转换系统.目前,碳载铂颗粒(Pt/C)是PEMFCs阴极氧还原反应(ORR)中使用最广泛的催化剂.然而,Pt与碳载体间的电子结构差异导致Pt纳米颗粒(Pt NPs)易从碳载体上脱落,严重降低了ORR的催化活性.此外,Pt的高成本和稀缺性也限制了其广泛应用.相比之下,Pt纳米枝晶(NDs)因具有高利用率的表面活性位点而备受关注.然而,Pt NDs的合成通常需要严格控制反应条件,且其与碳基底间的弱相互作用易导致活性位点损失和性能下降.因此,开发具有强金属载体相互作用的Pt复合碳催化剂对PEMFCs的实际应用至关重要.本文通过原位Cl-介导的生长策略,结合碳本征空位工程,成功制备了分散在富含碳本征空位的中空氮掺杂碳基底上的Pt NDs催化剂(Pt@HNC-V-800).拉曼光谱和电子顺磁共振光谱结果表明,碳本征空位的形成机制源于碳基底结构中氮原子的耗散,该过程引起碳原子的重新排列,进而产生了丰富的本征缺陷位点.X射线吸收光谱和X射线光电子能谱结果表明,与无碳空位的Pt@HNC催化剂相比,富含本征碳空位的样品(Pt@HNC-V-800)表现出较低的Pt-Pt键配位数(8.64)和更强的给电子效应.得益于Pt NDs丰富的活性位点及其与本征碳空位基底之间的强电子效应,Pt@HNC-V-800的ORR半波电位高达0.947 V,质量活性和比表面活性分别为1.55 A mg^(-1) Pt和1.85 mA cm^(-2),是商用Pt/C的8.2和6.8倍(0.191 A mg^(-1)Pt和0.27 mA cm^(-2)).加速耐久性测试结果表明,经20000次电势循环后,Pt@HNC-V-800的活性无明显变化,其活性损失远低于无碳本征空位的Pt@HNC材料和商业Pt/C催化剂.因此,与无碳本征空位的Pt@HNC材料相比,Pt@HNC-V-800的ORR活性和稳定性都有较大提升,进一步证实了碳本征空位工程协同Pt NDs策略的优越性.此外,密度泛函理论计算结果表明,Pt@HNC-V的丰富空位降低了氧中间体过电势,优化了ORR中间体在Pt NDs上的吸附能,进而提高了催化剂的ORR本征活性.同时,富碳本征空位的存在增强了Pt NDs在碳载体上的结合能,使Pt NDs不易在电势循环过程中脱离碳载体,从而增强了稳定性.综上所述,本文通过Pt NDs与碳本征空位工程协同效应策略,精准调控碳负载Pt基催化剂的结构,大幅提升其在酸性条件下的ORR性能,为进一步设计高性能的ORR电催化剂提供了新思路.
基金supported by National Natural Science Foundations of China(No.20773082)Shandong Department of Science and Technology(No.2006BS09003).
文摘Mesoporous carbon（MC） with surface area of 380 m^2/g was prepared and employed as the carbon support of Pt catalyst for counter electrode of dye-sensitized solar cells.Pt/MC samples containing 1 wt%Pt were prepared by reducing chloroplatinic acid on MC using wet impregnation.It was found that Pt nanoparticles were uniform in size and highly dispersed on MC supports.The average size of Pt nanoparticles is about 3.4 nm.Pt/MC electrodes were fabricated by coating Pt/MC samples on fluorine-doped tin oxide glass.The overall conversion efficiency of dye-sensitized solar cells with Pt/MC counter electrode is 6.62%,which is higher than that of the cells with conventional Pt counter electrode in the same conditions.
基金Sponsored by the Fundamental Research Funds for the Central Universities(Grant No.HIT.ICRST.2010005)
文摘In order to study the properties of supporting Pt catalysts for methanol oxidation,carbon-nanotubes are used by electrochemical deposition method. Different deposition turns,different cyclic voltammetry scanning speeds and processing time with ascorbic acid are investigated in this paper. The micrographs of Pt / CNTs catalysts are characterized by scanning electron microscopy,the electro-catalytic properties of Pt / CNTs catalysts for methanol oxidation are investigated by cycle voltammetry and chronoamperometry. The results show that the size of platinum will be greater with the faster scanning speed. After dissolution in ascorbic acid,Pt nanoparticles disperse uniformly. The obtained Pt / CNTs catalysts show a high electro-catalytic activity and stability.
基金supported by National Natural Science Foundation of China(Nos.11305218,11575253)the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2015262)+1 种基金the CASHIPS Director’s Fund(No.YZJJ201505)Anhui Provincial Natural Science Foundation for Distinguished Young Scholars of China(No.1608085J03)
文摘It is reported that the highly dispersed Pt nanoparticles on carbon nanotubes can be synthesized under mild conditions by in situ plasma treatment.The carbon nanotube was pretreated by O_2 plasma to transform into oxide carbon nanotubes（O-CNTs）,and then it was mixed with the precursors（the mixture of H_2 PtCl_6and PdCl_6）.After that,the O-CNTs and the precursors were simultaneously treated by H_2 plasma.The precursors were transformed into Pt-Pd nanoparticles（NPs）and the O-CNTs transformed into CNT.The synthesized CNT-based Pt-Pd nanoparticles were characterized by scanning electron microscopy,transmission electron microscopy,X-ray diffraction and X-ray photoelectron spectroscopy.All the analysis showed that the Pt-Pd nanoparticles were deposited on CNT as a form of face-centered cubical structure.
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.
文摘As a rapid uniform and efficient heating method, microwave irradiation has been widely used in chemical reaction and preparing nanomaterials. Here Pt/carbon nanotube(CNT) catalysts with w(Pt)=18.1% and 9.4 % were rapidly synthesized by microwave irradiation heating polyol process and employing the ethylene glycol solution of H 2PtCl 6 as the precursors in the presence of CNT support. TEM imaging showed that microwave-prepared Pt nanoparticles were very uniform in size, with an average size of 3.1 nm, and uniformly dispersed on the CNT surface. Electrochemical experiments demonstrated that microwave-synthesized Pt/CNT catalysts exhibited a higher catalytic activity for electrooxidation of liquid methanol than E-TEK Pt/C. The significant improvement in catalyst performance derives from that microwave-synthesized Pt nanoparticles have a uniform small particle size and uniforml dispersion on the CNT surface.
