Research Of Pt-Fe/C Alloy Catalyst Prepared By Pulse-microwave Synthesis Method For PEMFC

Pt-Fe/C catalyst for proton exchange membrane fuel cell (PEMFC) was prepared by a pulse-microwave assisted chemical reduction-heat treated synthesis method. The elemental content was tested by inductively coupled plasma (ICP) and energy dispersive X-ray(EDX) analysis. The microstructure and morphology of the as-prepared catalyst was characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray diffraction photoelectron spectroscopy (XPS). The electrocatalytic performance was measured by cyclic voltammetry (CV) and liner sweep votammetry (LSV). The pH value and microwave condition were researched. When the pH value is 11 and the microwave on time is 12s, the average size is 1.2 nm. Moreover, the catalyst nanoparticles are highly dispersed on the surface of carbon support. The electrochemical measurements show that the electrochemical surface area (ESA) of the catalyst is 47.50 m2·g-1In order to form alloy structure, pulse-microwave assisted chemical reduction-heat treated synthesis was taken to prepare Pt-Fe/C alloy catalyst, and the temperature and time of the heat treating are showed to be of great important effect on the size and activity of Pt-Fe nanoparticles. When the heating temperature was 500℃and the time was 3 hour, the Pt-Fe nanoparticles were uniform in size. Moreover, the Pt-Fe/C-500-3 alloy catalyst was highly dispersed on the surface of carbon support, and the TEM and XRD showed that the average Pt-Fe nanoparticles size was 1.8 nm. The electrochemical measurements showed that the ESA of the catalyst was 55.14 m2·g-1 The pulse-microwave assisted chemical reduction-pulse-microwave assisted H2 reducing treatment synthesis process is an more efficient method for preparing PEMFC catalyst, and the irradiation time and repeat times of the pulse-microwave assisted H2-reducing thermal treatment are of great important influences on the size and performance of Pt-Fe alloy catalysts. When the irradiation time was 14s and repeat time was 5 times, the Pt-Fe nanoparticles showed the best catalytic performance. Moreover, the XRD showed that the average Pt-Fe nanoparticles size was 2.3 nm. The electrochemical measurements showed that ESA of the catalyst was 51.79 m2·g-1 The sovent is also of importance to the catalyst performance.Pt/MWCNT and Pt/CNF was prepared by pulse-microwave assistant chemical reduction method. The pH value and microwave condition was researched. When the pH=11.5,the microwave heat 8s each time, the Pt/MWCNT have the best activity, the ESA was 66.02 m2·g-1. When the pH=10, the microwave heat 14s each time, the Pt/CNF have the best activity, the ESA was 59.17 m2·g-1. Most of the Pt/MWCNT have better activity than Pt/CNF.