Accelerating Kinetics of Alkaline Hydrogen Oxidation Reaction on Ru through Engineering Oxophilicity

Benefiting from its hydrogen binding energy being similar to that of platinum (Pt), ruthenium (Ru) is expected to replace Pt in the alkaline hydrogen oxidation reaction (HOR). Unfortunately, the adsorbed hydroxyl groups tend to cover Ru surfaces, making Ru unable to adsorb hydrogen, resulting in sluggish HOR kinetics. In this work, we demonstrate that alkaline HOR kinetics on Ru can be accelerated by combining it with highly oxophilic MoO2. Resulting from the stronger oxophilicity of MoO2, hydroxyl groups preferentially adsorb on MoO2, allowing Ru sites to adsorb hydrogen, thus facilitating HOR kinetics. Guided by the theoretical calculations, we synthesize a Ru/MoO2 catalyst for HOR, achieving a mass activity of 5.17 A mg(PGM)(-1), which is 13.6 times greater than that of commercial 20% Pt/C. Notably, a peak power density of 1.09 W cm(-2) is achieved using this Ru/MoO2 catalyst as the anode in an anion exchange membrane fuel cell (AEMFC).