Insight into the hydrogen oxidation electrocatalytic performance enhancement on Ni via oxophilic regulation of MoO2

Abstract Exploring platinum-group-metal (PGM) free electrocatalysts for hydrogen oxidation reaction (HOR) in alkaline media is essential to the progress of anion exchange membrane fuel cells (AEMFCs). In this work, a Ni/MoO2 heterostructure catalyst with comparable HOR activity in alkaline electrolyte with PGM catalyst was prepared by a simple hydrothermal-reduction method. Remarkably, the Ni/MoO2 presents a mass kinetic current density of 38.5 mA mgNi−1 at the overpotential of 50 mV, which is higher than that of the best PGM free HOR catalyst reported by far. Moreover, the HOR performance of Ni/MoO2 under 100 ppm CO shows negligible fading, together with the superior durability, render it significant potential for application in AEMFCs. A particular mechanistic study indicates that the excellent HOR performance is ascribed to the accelerated Volmer step by the incorporation of MoO2. The function of MoO2 was further confirmed by CO striping experiment on Pt/C-MoO2 that MoO2 can facilitated OH adsorption thus accelerate the HOR process. On account of the high performance and low cost, the Ni/MoO2 electrocatalyst encourages the establishment of high performance PGM free catalyst and shows significant potential for application in AEMFCs.