中文摘要：

采用两步化学还原法制备了Co@Pt／C电催化剂，并在还原气氛下对催化剂进行热处理．通过高分辨透射电镜（HR-TEM）$1]X射线光电子能谱（XPS）等技术对催化剂的微观结构和形貌进行表征．结果表明：形成的Co@Pt／C催化剂具有核壳结构，金属纳米颗粒均匀负载于碳上，其粒径分布范围较窄；热处理对催化剂的结构和形貌有较大影响．利用循环伏安（CV）法和线性伏安扫描（LSV）法表征催化剂的电化学活性、氧还原反应（ORR）动力学特性及耐久性．制备的Co@Pt／C催化剂在电解质溶液中表现出良好的电化学性能，核壳结构的形成有助于提高Pt的利用率．动力学性能测试表明催化剂的ORR反应以四电子路线进行．相比于合金催化剂．核壳结构催化剂的耐久性和稳定性有很大程度的改善．

英文摘要：

Co@Pt/C core-shell catalysts have been synthesized by a two-step chemical reduction method, followed by heat treatment in a H2 and N2 mixture. High resolution transmission electron microscopy （HR-TEM） and X-ray photoelectron spectroscopy （XPS） techniques were used to characterize the catalyst microstructure and morphology. The results indicate that the core-shell structure of Co rich in core and Pt rich in shell is formed and the nano-particles are highly dispersed on the surface of the carbon support. Heat treatment affects the structure and morphology of the catalysts. The electrocatalytic performance, kinetic characteristics of 02 reduction reaction （ORR）, and durability of the catalysts were measured by cyclic voltammetry （CV） and linear sweep voltammetry （LSV） techniques. It was found that the formation of the core-shell structure is favorable for improving the performance and utilization of Pt. The Co@Pt/C catalyst mechanism proceeds by an approximately four-electron pathway in acid solution, through which molecular oxygen is directly reduced to water. Compared with alloy catalysts, the formation of the core-shell structure obviously improves the catalyst durability.