We prepared a Pt/C catalyst for use in proton exchange membrane fuel cells (PEMFCs) by pulse-microwave assisted chemical reduction synthesis. The microstructure and morphology of the as-prepared catalyst was characterized by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The catalyst's electrocatalytic performance in the oxygen reduction reaction (ORR) was measured by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and constant potential polarization. The results indicate that pulse-microwave assisted chemical reduction synthesis is an efficient method to prepare PEMFC catalysts and that the pH and the microwave power largely influence the size and dispersion of Pt nanoparticles. At pH 10 and at a microwave power of 2 kW, the Pt nanoparticles were found to be uniform in size and the Pt nanoparticles size ranged between 1.3 and 2.4 nm with an average size of 1.8 nm. Additionally, the Pt nanoparticles were found to be highly dispersed on the surface of the carbon support. The electrochemical measurements showed that the electrochemical surface area (ESA)
Pt/cobalt-polypyrrole-carbon (Co-PPy-C)-supported catalysts were successfully prepared by pulse-microwave assisted chemical reduction. Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and X-ray diffraction (XRD) techniques were used to characterize the catalyst microstructure and morphology. The electrocatalytic performance, kinetic characteristics of the oxygen reduction reaction (ORR), and durability of the catalysts were measured by cyclic voltammetry (CV) and linear sweep voltammetry (LSV) techniques. It was found that the particle size of Pt/Co-PPy-C was about 1.8 nm, which was smaller than that of commercial Pt/C (JM) catalysts (2.5 nm). The metal particles were well-dispersed on the carbon support. The electrochemical specific area (ECSA) of Pt/Co-PPy-C (75.1 m 2 • g -1 ) was much higher than that of Pt/C (JM) (51.3 m 2 •g -1 ). The results of XPS showed that most of the Pt in the catalysts was in the Pt(0) state, and XRD results showed that the form of Pt was mainly the facecentered cubic lattice. The Pt/Co-PPy-C catalyst had the same half-wave potential as Pt/C (JM) and showed higher ORR activity. The Pt/Co-PPy-C catalyst proceeded by an approximately four-electron pathway in acid solution. After 1000 cycles of CV, the ECSA attenuation rates of Pt/Co-PPy-C and Pt/C were 13.0% and 24.0%
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