The Role of Hydroxide Binding Energy in Alkaline Hydrogen Oxidation Reaction Kinetics on RuCr Nanosheet†

Comprehensive Summary Unveiling the role of adsorbed hydroxide involved in the hydrogen oxidation reaction (HOR) under alkaline electrolyte is crucial for the development of advanced HOR electrocatalysts for the alkaline polymer electrolyte fuel cells (APEFCs). Herein, we report the synthesis of amorphous RuCr nanosheets with different molar ratios and their HOR performances under alkaline media. We find a volcano correlation between the Cr content in RuCr nanosheets and their alkaline HOR performance. Experimental results and density functional theory (DFT) calculation reveals that the optimized Cr content in RuCr nanosheets could lead to the optimum hydroxide binding energy (OHBE), contributes to their remarkable alkaline HOR performance with mass activity of 568.1 A center dot g(PGM)(-1) at 50 mV, 13-fold higher than that of Ru catalyst. When RuCr nanosheet is further used as the anodic electrocatalyst, a peak power density of 1.04 W center dot cm(-2) can be achieved in an APEFC.