Valence regulation of Ru/Mo2C heterojunction for efficient acidic overall water splitting

Hydrogen production by water splitting has the characteristics of clean, efficient, and strong operability. However, it is limited by the low activity and insufficient stability of cathode and anode catalysts. Therefore, cost-effective catalysts for efficient cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER) have to be developed. In this work, Ru/Mo2C heterojunctions are constructed to regulate the valence of Ru and Mo in the catalyst to simultaneously boost HER and OER in acidic conditions. Consequently, the overpotentials providing 10 mA/cm2 HER and OER in the acidic electrolyte are reduced to 40 mV and 215 mV, respectively. Finally, only 1.51 V applied voltage is required to achieve 10 mA/cm2 acidic overall water splitting. Taking stability into consideration, the Ru/Mo2C catalyst shows good application prospects in practical acid water electrolysis devices.