Promoting water formation in sulphate-functionalized Ru for efficient hydrogen oxidation reaction under alkaline electrolytes.

Improving the sluggish kinetics of the hydrogen oxidation reaction (HOR) under alkaline electrolytes plays a significant role in the practical application of alkaline polymer electrolyte fuel cells (APEFCs). Here we report a sulphate functionalized Ru catalyst (Ru-SO) that exhibits remarkable electrocatalytic performance and stability toward alkaline HOR, with a mass activity of 1182.2 mA mg, which is four-times higher than that of the pristine Ru catalyst. Theoretical calculations and experimental studies including electrochemical impedance spectroscopy and Raman spectroscopy demonstrate that the charge redistribution on the interface of Ru through sulphate functionalization could lead to optimized adsorption energies of hydrogen and hydroxide, together with facilitated H transfer through the inter Helmholtz plane and precisely tailored interfacial water molecules, contributing to a decreased energy barrier of the water formation step and enhanced HOR performance under alkaline electrolytes.