LAUSR

A clear understanding of catalytic activity enhancement mechanisms in fuel cell operation is necessary for a full degree translation of the latest generation of non-Pt/C fuel cell electrocatalysts into high performance electrodes in proton exchange membrane fuel cells (PEMFCs). In this work, PtNi nanowire (NW) array gas diffusion electrodes (GDEs) are fabricated from Pt nanowire arrays with Ni impregnation. A 2.84-fold improvement in the ORR catalytic activity is observed for the PtNi NW array GDE (cf. the Pt NW array GDE) using half-cell GDE measurement in 0.1 M HClO4 aqueous electrolyte at 25°C, in comparison to only 1.07-fold power density recorded in PEMFC single cell test. Ionomer is shown to significantly increase electrochemically active surface area of the GDEs, but the PtNi NW array GDE suffers from Ni ion contamination at a high temperature, contributing to decreased catalytic activities and limited improvement in operating PEMFCs.