▎ 摘　　要

In this work, Pd-Ni and Pd nanoparticles are deposited on Vulcan carbon (XC-72R), multi-walled carbon nanotubes (MWCNTs) and reduced graphene oxide (rGO) and investigated towards oxygen reduction reaction (ORR). The structural features of catalyst are characterized by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive X-ray spectroscopy (EDX). The ORR activity of catalysts is investigated via cyclic voltammetry (CV), rotating disk electrode (RDE), electrochemical impedance spectroscopy (EIS) and chronoamperometry techniques. Comparative CV analysis reveals higher electrochemical active surface area (ECSA) of Pd-Ni/rGO catalyst. This result suggests a general approach of a synergistic effect between Pd and Ni nanoparticles and better Pd-Ni dispersion on graphene sheets. The results from ORR measurements show that Pd-Ni/rGO has remarkable electrocatalytic activity and stability compared to Pd/C. The Koutecky-Levich and Tafel analysis suggest that the proposed main path in the ORR mechanism is direct four-electron transfer process with faster transfer kinetic rate on the Pd-Ni/rGO.