Pd_5Cu_4Pt oxygen reduction nanocatalyst for PEM fuel cells

摘要

Carbon dispersed Pd_5Cu_4Pt nanocatalyst synthesized by chemical reduction with NaBH_4 for the oxygen reduction reaction (ORR) in acid media is investigated. Nanocatalyst is physically characterized by transmission electron microscopy (TEM), high resolution transmission electron microscopy (HRTEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (DRX). Results demonstrate the formation of conglomerate nanometric particles ranging from 2 to 10 nm in size. Electrochemical activity is demonstrated by cyclic vol-tammetry (CV) and rotating disk electrode (RDE) techniques. The results show that the onset potential for the ORR on Pd_5Cu_4Pt is shifted by ca. 50 mV to more positive values and enhanced catalytic current densities are observed in comparison to carbon dispersed PdCu and Pd catalysts. The Pd_5Cu_4Pt tested as cathode electrode in a membrane-electrode assembly (MEA) shows a power density of 330 mW cm~(-2) at 0.5 V and 80 ℃, resulting an attractive low Pt content cathode nanocatalyst for PEM fuel cells.