聚苯胺基分散铂电极的电催化行为

为了改善铂基催化剂氧化甲醇的催化活性,采用循环伏安法制备了聚苯胺修饰分散铂电极(Pt-Pan/Pt)、聚苯胺和磷钼酸共同修饰分散铂电极(PMo12-Pt-Pan/Pt).并用循环伏安法研究了制备电极在0.5 mol·L-1H2SO4溶液中的电化学行为以及对甲醇氧化的催化效果.结果表明:PMo12-Pt-Pan/Pt电极对甲醇氧化具有很高的催化活性.PMo12-Pt-Pan/Pt电极对甲醇氧化的最大电流是33.43 mA,是Pt/Pt电极的1.37倍.催化活性的提高来源于聚苯胺和磷钼酸与铂的协同作用.     

硅钨酸修饰多晶铂电极及其电催化性能

通过循环伏安扫描制备了硅钨酸修饰多晶铂电极，在电极制备过程中发现，SiW12在Pt电极表面的氢区发生了氧化-还原反应，而在氧区使电极表面含氧粒子的吸附增加。通过循环伏安和恒电位I-t曲线研究了该修饰电极在硫酸溶液中的电化学行为和对甲醇氧化的电催化作用。研究结果表明：硅钨酸修饰多晶铂电极提高了甲醇氧化的催化活性和抗CO中毒性。     

稀土多金属氧酸盐修饰铂电极对甲醇电催化氧化的促进作用

运用循环伏安法在光滑的铂电极表面上修饰了稀土多金属氧酸盐,并用交流阻抗进行了表征,研究了该电极对甲醇的电催化氧化行为。实验结果表明,与未修饰的光滑的铂电极相比,稀土多金属氧酸盐修饰的电极对甲醇电催化氧化速率明显增加。并测定了该修饰电极电催化氧化的动力学参数。     

超声法制备纳米Pt/MWCNT催化剂及其在CO2传感器上的应用

采用超声合成法制备了纳米铂/多壁碳纳米管复合催化剂(Pt/MWCNT),通过场发射扫描电镜(FE-SEM)、X-射线衍射(XRD)及电化学技术表征了该催化剂的性质.结果表明:纳米Pt均匀地镶嵌在MWCNTs表面,粒径为40±20 nm.该催化剂对CO2的还原呈现良好的催化作用,可用作制备CO2电化学传感器,CO2在纳米铂/多壁碳纳米碳管修饰玻碳电极上的还原电流响应(Pt/MWCNTs/GCE),分别在1～10 ppm和10～100 ppm两个浓度范围内呈良好的线性关系,检测限为1 ppm.     

热处理对Pt纳米线电催化性能的影响

采用阳极氧化铝(AAO)模板法电化学沉积制备了Pt纳米线催化剂,并进行了热处理。通过X射线衍射(XRD)、扫描电子显微镜(SEM)和电化学测试对热处理前后Pt纳米线催化剂的晶体结构、形貌和电催化性能进行了表征,并与商业碳载铂(Pt/C)做对比。SEM照片表明制备了表面粗糙的Pt纳米线。循环伏安法(CV)和计时电流曲线表明,Pt纳米线较Pt/C催化活性高,退火后Pt纳米线更利于甲醇氧化,且稳定性更好。旋转圆盘电极(RDE)测试研究发现,未经热处理的Pt纳米线催化剂氧还原反应(ORR)极化曲线的半波电势相对Pt/C有正移,有更大的极限扩散电流,利于氧还原反应的发生。     

多孔生物形态碳/铂颗粒复合材料的电化学行为

利用热解法制备了具有一定生物形态的多孔碳材料,并采用电沉积方法在所得碳材料表面沉积贵金属铂微粒.借助具有良好成膜能力的壳聚糖,把所得到的C-Pt复合材料修饰在玻碳电极表面,运用电化学方法研究了C-Pt复合材料修饰的玻碳电极对过氧化氢的电催化行为.结果发现,铂微粒和碳材料之间的协同作用大大提高了修饰电极的催化性能,对过氧化氢具有良好的电催化活性.     

Ti/nano-TiO2-Pt复合电极催化甲醇氧化的研究

采用溶胶-凝胶法(sol-gel)制备纳米TiO2(Ti/nano-TiO2)膜电极,再用电沉积法在纳米TiO2膜上修饰Pt微粒,制成Ti/nano-TiO2-Pt复合电极.用循环伏安法研究了纯Pt丝电极和Ti/nano-TiO2-Pt电极对甲醇氧化的电催化活性以及稳定性.结果表明:对甲醇氧化,复合电极比Pt丝电极具有更高的催化活性,且对甲醇氧化中间产物CO的吸附量少,因而不易中毒;复合电极载铂量达到一定值时,电极具有最强的催化活性.     

杂多酸修饰碳载铂钌电极的电催化性能

利用化学还原法合成了PtRu/C催化剂,并通过XRD测试表明铂钌形成了合金相.分别采用磷钼酸和磷钨酸对PtRu/C电极进行了修饰,并用循环伏安曲线和不同电位下的恒电位I-t曲线测试了它们的性能.结果发现:磷钼酸修饰的PtRu/C电极氧化甲醇的电催化活性更高.     

Fe掺杂对质子交换膜燃料电池Pt/C催化剂性能的影响

用铁作掺杂元素,通过液相均相沉淀-气/固高温还原两段反应方法制备了碳载Pt-Fe合金催化剂,比较了3种不同Fe含量催化剂的电催化性能.采用X射线衍射和X光电子能谱技术研究了Fe掺杂对Pt/C催化剂晶体结构及表面元素存在形态的影响.结果显示:Pt-Fe/C催化剂比单一Pt/C催化剂有更小的晶格参数,其中Fe元素可能的存在形态应为与铂结合的合金态,但不排除表面存在部分氧化态.单电池放电稳定性实验表明:在200 mA·cm-2电流密度下放电时电池电压基本稳定,其中Pt与Fe摩尔比为1∶1时电极催化效果相应较好,但大电流密度放电时电池电压下降比单一Pt/C催化剂电极的快,这说明Fe的加入能提高催化剂的电催化性能,但阴极表面氧原子浓度较大时,Fe可能发生氧化而使得电极稳定性受到影响.     

过渡金属取代磷钼酸修饰铂电极的电化学行为

在证实了磷钼酸修饰铂电极对甲醇氧化具有较高活性的基础上，合成了3种过渡金属取代的磷钼酸，通过红外光谱测试仍为Keggin结构，并制备了过渡金属取代磷钼酸修饰铂电极，研究了修饰铂电极在硫酸溶液中的电化学行为及对甲醇的催化氧化作用。研究结果表明，3种过渡金属取代的磷钼酸修饰铂电极均对甲醇氧化表现出较高的催化活性，其中锰取代的磷钼酸修饰电极对甲醇的催化活性最高。     

Comparative studies of adsorbed CO and methanol electrooxidation on carbon supported Pt and PtRu catalysts in acid solution

1. Introduction Direct methanol fuel cells (DMFCs) have con-siderable advantages compared to gas feed (H2/air) polymer electrolyte membrane (PEM) fuel cells [1-2]. The hydrogen PEM fuel cells use gaseous hy-drogen as fuel. But there is no source and infra-structure established yet for hydrogen distribution and storage, neither as a liquid nor as a gas. How-ever, the DMFC, similar to a proton exchange membrane fuel cell (PEMFC), uses methanol fuel directly for electric power generation …     

Preparation and catalytic activity of CO-resistant catalyst core-shell Au@Pt/C for methanol oxidation

Au@Pt core-shell nanoparticles were successfully synthesized by a successive reduction method and then assembled on Vulcan XC-72 carbon surface.Furthermore,its composition,morphology,structure,and activity towards methanol oxidation were characterized by UV-vis spectrometry,transmission electron microscopy (TEM),high-resolution TEM (HRTEM),X-ray diffraction (XRD),X-ray photoelectron spectroscopy (XPS),and cyclic voltammetry (CV).Results reveal that Au@Pt/C catalyst has better activity towards methanol oxidation than the pure platinum prepared under the same conditions.When the atomic ratio of Au to Pt in the prepared Au@Pt/C catalyst is 1∶2,this catalyst exhibits best electrocatalytic activity towards methanol oxidation in acidic media,and the peak current density on this catalyst is ～2.0times higher than that on Pt/C catalyst.The better catalytic activity of Au@Pt/C results from its better resistance to toxic CO than Pt/C because the CO oxidation on Au@Pt/C is 60 mV more negative than the case on Pt/C.     

Fabrication, annealing, and electrocatalytic properties of platinum nanoparticles supported on self-organized TiO2 nanotubes

The platinum nanoparticles supported on self-organized TiO2 nanotubes （Pt-TiO2/Ti） were prepared using electrochemical anodic oxidation followed by cathodic reduction. The structure and chemical nature of the Pt-TiO2/Ti electrocatalyst were investigated by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. Both XRD and SEM results indicate the presence of platinum on nanotubular TiO2. The stability of the Pt deposits was also investigated in 0.5 mol/L H2SO4 solution by cyclic voltammetry. The electrocatalytic activity of the Pt-TiO2/Ti catalyst exhibits enhancement effect during electro-oxidation of methanol when annealed to anatase. Successive cyclic voltam- mograms of methanol oxidation on the Pt-TiO2/Ti electrocatalyst shows unique electrocatalytic characteristics when compared to methanol oxidation on the bulk Pt catalyst. This is because of further quick oxidation of adsorbed CO by Pt （111） facets of Pt particles on self-organized TiO2 nanotubes when the formation of an electroactive film onto the working catalyst surface occurs.     

Electrocatalytic performance of Pd–Ni nanowire arrays electrode for methanol electrooxidation in alkaline media

A successful approach to prepare the Pd–Ni nanowire arrays electrode without carbon supports was reported. The morphology and crystallinity of nanowire were characterized by transmission electron microscopy, selected-area electron diffraction(SAED), X-ray diffraction(XRD), and X-ray photoelectron spectroscopy(XPS) analyses, respectively. The results show that the diameters of the nanowire are in the range of 65–75 nm, and the polycrystalline binary solid solution alloy is formed in the Pd–Ni nanowire. Cyclic voltammograms, chronoamperograms, and electrochemical impedance spectroscopy demonstrate that the Pd–Ni nanowire arrays electrodes show excellent electrocatalytic performance for methanol oxidation in alkaline media. The catalytic activity of Pd–Ni nanowire arrays electrode is *1.39 times higher than that of the Pd nanowire arrays electrode and *2.28 times higher than that of the commercial Pd/C catalyst. This is mostly owing to the transfer of electron density from Ni to Pd. These results indicate that Pd–Ni nanowire arrays electrode is very promising in an alkaline direct methanol fuel cell.     

Platinum-polyaniline-modified carbon fiber electrode for the electrooxidation of methanol

Platinum was electrodeposited onto a polyaniline-modified carbon fiber electrode by the cyclic voltammetric method in sulfuric acid, which may enable an increase in the level of platinum utilization currently achieved in electrocatalytic systems. This electrode preparation consists of a two-step procedure: fLrst electropolymerization of aniline onto carbon fiber and then electrodeposition of platinum. The catalytic activity of the platinum-polyaniline-modified carbon fiber electrode (Pt/PAni/C) was compared with that of a bare carbon fiber electrode (Pt/C) by the oxidation of methanol. The maximum oxidation current of methanol on Pt/PAni/C is 50.7 mA.cm^-2, which is 6.7 times higher than 7.6 mA.cm^-2 on the Pt/C.Scanning electron microscopy was used to investigate the dispersion of the platinum particles of about 0.4μm.     

PtPb/ C 催化剂的制备及其对甲酸电氧化的催化性能

目的通过Pb元素的添加来提高Pt/C催化剂电催化氧化甲酸的性能。方法通过乙二醇协助硼氢化钠还原法,以氯铂酸为Pt源和硝酸铅为Pb源制备不同原子比的PtxPb/C催化剂。采用X射线衍射光谱法(XRD)和透射电子显微镜技术(TEM)表征样品的晶体结构和颗粒形貌;采用循环伏安法表征样品催化氧化甲酸的性能。结果利用乙二醇协助硼氢化钠还原法成功制得了Pt和Pb原子比不同的PtxPb/C催化剂,XRD和TEM测试结果表明这些样品均为Pt的面心立方结构,且颗粒大小均一、分散均匀,其平均粒径为4 nm左右。循环伏安测试结果表明PtxPb/C催化剂催化氧化甲酸的性能优于商业Pt/C催化剂的催化性能,且受Pt和Pb原子比的影响,当原子比为5∶1时,其对氧化甲酸的催化性能最好,峰电位对应的Pt的比质量活性达到2000 m A/(mg Pt),远远高于商业Pt/C,同时计时电流曲线表明其具备良好的稳定性。结论 Pb原子的加入影响了Pt原子的电子结构,与Pb对Pt的协同作用共同促进了CO等中间产物在Pt表面的快速氧化,降低了催化氧化甲酸的初始电位,促使甲酸在低电位直接氧化为CO2和H2O,提高了其催化氧化甲酸的峰电流,有效减轻了Pt中毒,提高了其催化活性。     

Au-Pt双金属纳米粒子的制备及其电催化性质

在PEG10000/Vc/HAuCl4体系中,用Vc还原HAuCl4制备金纳米粒子,以所制备的金纳米粒子为晶种,通过控制HAuCl4与H2PtCl6的质量比,制备不同Pt/Au比的双金属纳米粒子,并进一步研究其对H2O2电化学氧化的催化作用。紫外-可见光谱(Uv-vis)、透射电子显微镜(TEM)、选区电子衍射(SAED)、X射线粉末衍射(XRD)等实验结果表明：Au-Pt双金属纳米粒子为面心立方结构的合金。用循环伏安法对Au-Pt双金属纳米粒子修饰的玻碳电极的电化学性能进行测试,结果表明：Au-Pt双金属纳米粒子对H2O2电化学氧化有一定的催化作用。催化效率随Au-Pt双金属粒子中Pt含量的增加而增加。     

Electrocatalytic oxidation of methanol on PPy electrode modified by gold using the cementation process

The preparation by the electrochemical cementation process of dispersed gold microparticles on polypyrrole (PPy) coatings on iron surface and their electrocatalytic activity towards methanol oxidation were studied. The reaction of cementation of gold onto Fe/PPy electrode was shown to be under chemical control with a high activation energy.These films were investigated by scanning electron microscopy (SEM), energy-dispersive X-ray analysis (EDX) and cyclic voltammetry. These dispersed Au microparticles exhibit higher electrocatalytic activity than a bare gold electrode towards the electrochemical oxidation of methanol in acidic media.