Effect of Microwave Power and Irradiation Time on the Performance of Pt/C Catalysts Synthesized by Pulse-microwave Assisted Chemical Reduction

Abstract

Pt/C catalysts for polymer electrolyte membrane fuel cells were synthesized by pulse-microwave assisted chemical reduction. X-ray diffraction (XRD) and high resolution transmission electron microscope (HRTEM) were used to investigate the microstructure and morphology of the as-prepared catalysts. The electrochemical surface area (ESA) was studied by cyclic voltammetry (CV). Membrane electrode assemblies were fabricated and the as-prepared catalysts were evaluated. The particle size and distribution of Pt nanoparticles on the carbon support greatly depended on the microwave power and irradiation time. XRD and HRTEM showed that the Pt/C catalysts possessed the smallest mean Pt particle size (1.9 nm) and the most uniform distribution among all the synthesized catalysts when the microwave was on for 12 s and off for 180 s, and this was repeated 6 times at a microwave power of 2 kW. A CV revealed that the ESA of the catalyst was 72.3 m 2 /g and the corresponding maximum power density was 0.572 W/cm 2 . 采用脉冲微波辅助化学还原法制备了质子交换膜燃料电池 (PEMFC) 用 Pt/C 催化剂. 通过 X 射线衍射 (XRD) 和高分辨透射电镜 (HRTEM) 等分析技术对催化剂的微观结构和形貌进行了表征. 利用循环伏安 (CV) 法计算了催化剂的电化学比表面积. 在此基础上制备了膜电极 (MEA) 并组装成单电池, 考察了制备的 Pt/C 催化剂作为单电池阴极催化剂材料的电催化性能. 微波功率和微波作用时间对 Pt 颗粒直径和分散有重要影响. XRD 和 HRTEM 结果表明, 在微波功率为 2 kW, 微波作用 12 s, 豫驰 180 s, 且重复 6 次的条件下, 制得的催化剂中铂纳米粒子颗粒直径小, 分散均一, 其平均粒径为 1.9 nm. CV 结果表明, 该条件下制得的催化剂电化学比表面积达到 72.3 m 2 /g, 且该催化剂对应的单电池最高功率密度为 0.572 W/cm 2 . The microwave irradiation time and microwave power can affect the performance of Pt/C catalysts synthesized by a pulse-microwave assisted chemical reduction method.