Copper-Tailored Molybdenum-Nickel Catalyst Boosts Hydrogen Oxidation and Suppresses Parasitic Oxygen Reduction for Durable Fuel Cells.

Numerous existing strategies struggle to mitigate reverse-current decay (RCD) during startup and shutdown in polymer electrolyte fuel cells to avoid cathode corrosion, but the added system complexity and cost are drawbacks. Here we report that modification of a molybdenum-nickel alloy through the doping of copper enables a non-noble electrocatalyst (MoNi3.6Cu0.4) that efficiently catalyzes hydrogen oxidation reaction (HOR) while catalytically inactive toward oxygen reduction reaction (ORR) in alkaline media, making it ideal for fuel-cell anode because the instantaneous interfacial potential jump originated from the parasitic ORR during device startup/shutdown can be surmounted. The catalyst, when assembled in the anode of an anion exchange membrane fuel cell, manifests substantially improved corrosion-resistant ability compared with that of state-of-the-art carbon-supported platinum (Pt/C) catalyst. The basis for the achieved performances reveals to be the copper dopants that increase the hydrogen bonding of interfacial water for enhanced HOR, yet weaken molecular oxygen adsorption while stabilizing hydroxyl adsorption for ORR suppression.