Accelerating\nKinetics of Alkaline Hydrogen Oxidation\nReaction on Ru through Engineering Oxophilicity

Benefiting from its hydrogen binding energy being similar\nto that\nof platinum (Pt), ruthenium (Ru) is expected to replace Pt in the\nalkaline hydrogen oxidation reaction (HOR). Unfortunately, the adsorbed\nhydroxyl groups tend to cover Ru surfaces, making Ru unable to adsorb\nhydrogen, resulting in sluggish HOR kinetics. In this work, we demonstrate\nthat alkaline HOR kinetics on Ru can be accelerated by combining it\nwith highly oxophilic MoO<sub>2</sub>. Resulting from the stronger\noxophilicity of MoO<sub>2</sub>, hydroxyl groups preferentially adsorb\non MoO<sub>2</sub>, allowing Ru sites to adsorb hydrogen, thus facilitating\nHOR kinetics. Guided by the theoretical calculations, we synthesize\na Ru/MoO<sub>2</sub> catalyst for HOR, achieving a mass activity of\n5.17 A mg<sub>PGM</sub><sup>–1</sup>, which is 13.6 times greater\nthan that of commercial 20% Pt/C. Notably, a peak power density of\n1.09 W cm<sup>–2</sup> is achieved using this Ru/MoO<sub>2</sub> catalyst as the anode in an anion exchange membrane fuel cell (AEMFC).