中文摘要：

采用化学还原法合成了微结构不同的纳米碳纤维（板式、鱼骨式、管式）载铂催化剂（分别记为Pt／p-CNF、Pt／f-CNF、Pt／t—CNF）．通过高分辨透射电镜（HRTEM）和X射线衍射（XRD）等分析技术对催化剂的微观结构进行了表征，并利用循环伏安（CV）法分析了催化剂的电化学比表面积（ESA）．在此基础上，制备了膜电极（MEA），通过单电池测试了催化剂的电催化性能．结果表明：铂纳米粒子在不同的纳米碳载体上表现出不同的粒径，在板式、鱼骨式和管式纳米碳纤维上的铂纳米粒子平均粒径分别为2．4、2.7和2．8nm．板式纳米碳纤维载铂催化剂作单电池阳极时表现出良好的电催化性能，其对应的最高功率密度可达0．569W·cm^-2，高于鱼骨式纳米碳纤维载铂催化剂和管式纳米碳纤维载铂催化剂对应的最高功率密度（分别为0．550和0．496W·cm^-2）．同时，也制备了碳黑（Pt／XC-72）载铂催化剂．相比于Pt／XC-72，纳米碳纤维载体上的铂纳米颗粒有较小的粒径、较好的分散和较高的催化活性，说明纳米碳纤维是质子交换膜燃料电池（PEMFCs）催化剂的良好载体．

英文摘要：

Pt nanoparticles supported on carbon nanofibers （Pt/CNFs） with different microstructure, i.e., platelet CNF （Pt/p-CNF）, fish-bone CNF （Pt/f-CNF）, and tubular CNF （Pt/t-CNF） were synthesized by a chemical reduction method. X-ray diffraction （XRD） and high resolution transmission electron microscope （HRTEM） were applied to characterize the structure of the as-prepared catalysts. The electrochemical surface area （ESA） was studied by cyclic voltammetry （CV）. Membrane electrode assemblies （MEAs） with the as-prepared catalysts were fabricated and tested. We found that Pt nanoparticles showed different particle size and dispersion on the three kinds of CNF supports and the mean size of the Pt nanoparticles on p-CNF, f-CNF, and t-CNF was 2.4, 2.7, and 2.8 nm, respectively. Single cell testing indicated that the cell with Pt/p-CNF as the anode catalyst gave better performance compared to Pt/f-CNF and Pt/t-CNF. The maximum power density was 0.569 W. cm-2 for Pt/p-CNF, which was higher than that for Pt/f-CNF （0.550 W. cm-2） and Pt/t-CNF （0.496 W-cm-2）. Furthermore, Pt nanoparticles supported on carbon black （Pt/XC-72） were also prepared. Pt nanoparticles supported on CNFs have been shown to have a smaller particle size and better dispersion than those on XC-72, and this proves that CNFs can be an efficient electrocatalyst support for proton exchange membrane fuel cells （PEMFCs）.