Au-Pt催化剂的控制合成及其对乙醇电氧化性能  

Controlled Synthesis of Gold-Platinum Catalysts for Ethanol Electro-oxidation Reaction

作　　者：吴匡衡 周亚威 马宪印 丁辰 蔡文斌 Wu Kuangheng a;Zhou Yawei a;Ma Xianyin b;Ding Chen a;Cai Wenbin a(a Shanghai Key Laboratory of Molecular Catalysis＇ and Innovative Materials, Collaborative Innovation Center of Chemistry for Energy Materials, Department of Chemistry, Fudan University, Shanghai 20043;b Shanghai Key Laboratory of Materials Protection and Advanced Materials in Electric Power, College of Environmental and Chemical Engineering, Shanghai University of Electric Power, Shanghai 200090)

机构地区：[1]复旦大学化学系能源材料化学协同创新中心上海市分子催化与功能材料表面重点实验室,上海200433 [2]上海电力学院环境与化学工程学院上海市电力材料防护与新材料重点实验室,上海200090

出　　处：《化学学报》2018年第4期292-297,共6页Acta Chimica Sinica

基　　金：国家自然科学基金(Nos.21473039;21733004);上海市国际科技合作基金(No.17520711200);973计划(No.2015CB932303)资助项目~~

摘　　要：乙醇电氧化(EOR)是直接乙醇燃料电池和电解乙醇制氢共有的阳极反应.Au@Pt核壳和AuPt合金是广泛使用的两种电催化材料,迄今尚无两者对EOR性能的对比研究.以CO作为还原剂和淬灭剂合成了近似Pt单层的Au@Pt/C催化剂,作为对照,以Na BH4还原法合成了相同Au∶Pt物质的量比和金属载量的AuPt/C催化剂;运用透射电子显微镜(TEM)、扫描透射电子显微镜-能谱仪(STEM-EDS)、X射线粉末衍射(XRD)和X射线光电子能谱(XPS)等手段综合表征了两者结构之差异,同时以电化学循环伏安法和计时电流法测试了在碱性体系中其对EOR的电催化性能.结果表明,相比于商业化的Pt/C和Au/C,Au@Pt/C和AuPt/C对EOR的活性和稳定性均有着显著提升;Au@Pt/C对EOR的电催化活性和对C—C键断裂能力略优于AuPt/C.双金属催化剂中Au与Pt之间的晶格应力和部分电荷转移等效应可能是其性能提升的主要原因.Ethanol oxidation reaction（EOR） is a common anode process for direct ethanol fuel cell（DEFC） and ethanol reforming electrolyzer. Au@Pt and AuPt alloy are widely used bimetallic catalysts, yet no comparative study has been reported of electrocatalysis of EOR on these two differently structured catalysts. The present work aims to synthesize and characterize carbon supported Au@Pt and AuPt with controlled composition and size, and compare their electrocatalytic activities and stabilities toward EOR in alkaline media. For the synthesis of Au@Pt/C, a 5-nm Au colloid was first obtained by adding excessive amount of sodium borohydride to a chloroauric acid precursor containing sodium citrate with a mixed ice-water bath. CO gas was bubbled into the Au colloidal solution at 60 ℃ under strong stirring to reduce a desired amount of potassium tetrachloroplatinate（II） to terminate Pt quasi-monolayer shell on Au nanoparticle core. A sonicated carbon black（Vulcan XC-72） aqueous slurry was then dropwise added to the above Au@Pt colloid, and the mixture was kept stirring for 48 h to ensure the exhaustive loading of Au@Pt nanoparticles onto the carbon support. For the synthesis of AuPt/C with the same Au：Pt molar ratio and metal loading as that for Au@Pt/C, coreduction of the Au（III） and Pt（II） species was attained by using sodium borohydride as the reducing agent with the rest procedures being same as the above mentioned. X-ray diffractometry（XRD） revealed that the diffraction peaks for Au@Pt/C were virtually same as those for Au/C, consistent with a Pt quasi-monolayer, while the diffraction peaks for AuPt/C located in between those for Au/C and Pt/C. X-ray photoelectron spectroscopy（XPS） results were consitent with the different structures of the two catalysts, and the Pt core level shift suggested an upshift of Pt d-band center for both bimetallic catalysts. Cyclic voltammetry and chronoamperometry revealed markedly increased EOR current on Au@Pt/C and AuPt/C, as compared to that of Pt/C and

关 键 词：乙醇电氧化 电催化 金-铂催化剂 核壳结构 合金结构 

分 类 号：O643.36[理学—物理化学] TM911.4[理学—化学]