Interfacial Electronic Coupling of NC@WO3-W2C Decorated Ru Clusters as a Reversible Catalyst toward Electrocatalytic Hydrogen Oxidation and Evolution Reactions.

Abstract

Designing a bifunctional catalyst for hydrogen oxidation reaction (HOR) and hydrogen evolution reaction (HER) is significant toward developing sustainable hydrogen-electric conversion systems. Herein, we develop a cost-effective bifunctional catalyst of Ru/N-doped Carbon@WO3-W2C (Ru/NC@WOC) via co-precipitation and polyol reduction. Ru/NC@WOC shows superior HOR/HER activity in alkaline solution in comparison with commercial Pt/C. HOR electrochemical tests show that the mass activity at 0.05 V (1.96 mA ug-1Ru ) and exchange-current density are 7.5 and 1.2 times that of Pt/C. Additionality, the Ru/NC@WOC exhibit up 30-fold HOR activity in mass activity compared with benchmark Ru/C. Moreover, it also displays exceptional electrocatalytic HER with overpotential of 31 mV@10 mA cm-2 and 119 mV@100 mA cm-2 , surpassing Pt/C, benchmark Ru/C and most of the previously reported electrocatalysts. The outstanding catalytic activity of Ru/NC@WOC probably arises from the synergy between Ru and NC@WOC matrix, suitable hydrogen binding energy, and highly conductive substrate. Thus, this work may pave a new avenue to fabricate low-cost bifunctional HOR/HER catalysts for alkaline fuel cells and water electrolyzer.