中文摘要：

采用两步还原法制得Co@Pt／C核壳结构催化剂，其中Co与Pt的总质量分数为20％．通过改变金属前驱体的用量，制备了不同Co：Pt原子比的Co@Pt／C催化剂，以20％（W）Co@Pt（1：1）／C与20％（忉Co@Pt（1：3）／C表示．采用透射电镜（TEM）、光电子射线能谱分析（XPS）、循环伏安（CV）、线性扫描伏安（LSV）等方法考察了其结构与性能，并与实验室早先制备的40％（w）Co@Pt／C催化剂进行了比较．自制20％Co@Pt（1：1），C与20％Co@Pt（1：3）／C催化剂的金属颗粒直径约为2．2—2．3nm，在碳载体上分散均匀，粒径分布范围较窄，电化学活性比表面积（ECSA）分别为56和60m^2·g^-1，均超过商用催化剂20％Pt／C（E-tek）（ECSA=54m^2·g^-1）．20％Co@Pt（1：1）／C与20％Co@Pt（1：3）／C的半波电位相较于40％Co@Pt（1：1）／C和40％Co@Pt（1：3）／C均向正向移动，表现出更好的氧还原（ORR）催化活性，并有望降低催化剂的成本，在质子交换膜燃料电池领域表现出良好的应用前景．

英文摘要：

Core-shell structured Co@Pt/C electrocatalysts containing different mass fractions of Co to Pt, which are represented as 20% （w） Co@Pt（1：1）/C and 20% （w） Co@Pt（I：3）/C, were prepared by changing the ratio of metatlic precursors using a successive reduction method. The structure and electrochemical performance of the as-prepared catalysts were characterized by transmission electron microscopy （TEM）, X-ray photoelectron spectroscopy （XPS）, cyclic voltammetry （CV）, and linear sweep voltammetry （LSV）. The performance of the as-prepared catalysts was compared with that of 40% （w） Co@Pt/C catalyst we synthesized previously. The sizes of Co@Pt（l：l） and Co@Pt（1：3） particles ranged from 2.2 to 2.3 nm, and the metal particles were well dispersed on the carbon support. The electrochemical specific area （ECSA） of 20% Co@Pt（I：I）/C （56 m2. g-l） and 20% Co@Pt（I：3）/C （60 m2. g-l） were higher than that of commercial 20% Pt/C （E-tek） （54 m2- g-Z）. Compared with those of 40% Co@Pt（I：I）/C and 40% Co@Pt（I：3）/C, the half-wave potentials of 20% Co@Pt（I：I）/C and 20% Co@Pt（I：3）/C shifted to the positive direction, and they correspondingly showed improved catalytic performance. The low cost and high performance of the 20% Co@Pt/C catalyst make it a promising Iow-Pt catalyst for proton exchange membrane fuel cells.