Oxygen-modified supra-nanometer-sized RuPt for robust alkaline HER/HOR†

Platinum (Pt) is a highly efficient catalyst for the hydrogen evolution reaction (HER) and the hydrogen oxidation reaction (HOR). However, the scarcity of Pt necessitates the development of catalysts with low Pt content while maintaining high activity. In this study, we report the synthesis of oxygen-modified supra-nanometer-sized RuPt nanocrystals with low Pt content by a simple air annealing method to achieve a catalyst with high activity. The annealed catalyst, RuPt/C-200, exhibits a very low overpotential of only 3.8 mV at 10 mA cm⁻², a low Tafel slope of 16.6 mV dec⁻¹, and a 2.8-fold increase in mass activity at an overpotential of 0.06 V for HER compared to the unannealed catalyst. Additionally, the HOR exchange current density increases 2.9-fold compared to the unannealed catalyst. AEMWE tests confirm the application potential of RuPt/C-200, while density-functional-theory (DFT) calculations reveal that oxygen modification, by optimizing the hydrogen binding energy, plays a crucial role in improving the catalytic performance of RuPt. This work highlights that combining the oxygen modification strategy with the nanoscale size effect could advance the development of high-performance RuPt electrocatalyst for both alkaline HER and HOR.