Abstract: Carbon supported platinum nanowires (Pt NWs/C), acting as cathode catalyst for proton exchange membrane fuel cell (PEMFC), were synthesized by reducing H₂PtCl₆ with HCOOH at room temperature without assistance of template. The catalyst microstructure and morphology were characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The Pt NWs/C had an average cross-sectional diameter of (4.0±0.2) nm and a length of 15-25 nm. Good electrocatalytic performance and oxygen reduction reaction (ORR) of the as-prepared catalyst was characterized by cyclic voltammetry (CV) and linear sweep voltammetry (LSV). Two membrane electrode assemblies (MEAs) were fabricated, with Pt NWs/C and Pt/C as cathode catalyst respectively, and tested for comparison. The maximum power densities of Pt NWs/C and Pt/C, respectively were 705.6 mW·cm^-2 and 674.4 mW·cm^-2. Afterwards, an 18-cell stack with Pt NWs/C as cathode catalyst and a 20-cell stack with Pt/C as cathode catalyst were built for testing. Maximum power densities were 409.2 mW·cm^-2 and 702.7 mW·cm^-2, and coefficients of variation (C_v) of individual cell were 16.1% and 4.36% at the maximum power density, respectively. Data analysis indicated that Pt NWs/C for the cathode in a MEA exhibited good catalytic activity at a scale-up level, however, as compared with the commercial Pt/C catalyst, CV performance and uniformity should be improved. This work not only sheds light on the scale-up possibility of Pt NWs/C catalyst, but also provides a possibility for further durability test before its application in a fuel cell vehicle.

Key words: fuel cells, carbon-supported Pt nanowires, catalyst, electrochemistry

摘要： 采用无模板法制备了用于质子交换膜燃料电池（PEMFC）的碳载铂纳米线（Pt NWs/C）阴极催化剂，使用透射电镜（TEM）和X射线衍射图谱技术（XRD）对催化剂的微观结构和形貌进行了表征。研究结果表明，制备的铂催化剂具有纳米线的结构，平均截面直径为（4.0±0.2）nm，线长为15～25 nm。利用循环伏安（CV）法和线性伏安扫描法（LSV）表征催化剂的电化学活性和氧还原反应（ORR）特性，结果表明制备的Pt NWs/C催化剂电化学特性良好。利用Pt NWs/C和Pt/C作为阴极催化剂制备膜电极（MEA），并进行测试，最大功率密度分别为705.6 mW·cm^-2和674.4 mW·cm^-2。然后以Pt NWs/C和Pt/C为阴极催化剂组装了18片和20片的电堆，并进行性能测试，电堆的最大功率密度分别为409.2 mW·cm^-2和702.7 mW·cm^-2，单电池电压差异系数（C_v）分别为16.1%和4.36%，这表明Pt NWs/C作为阴极催化剂在放大后的膜电极组件（MEA）里表现出较好的催化活性，但与商业催化剂相比其性能与均一性还有待提高。该研究可为Pt NWs/C催化剂放大制备提供依据，同时可为后续的基于Pt NWs/C的电堆的耐久性测试和车载应用奠定基础。

关键词: 燃料电池, 碳载铂纳米线, 催化剂, 电化学