Electronic structure optimizing of Ru nanoclusters via Co single atom and N, S co-doped reduced graphene oxide for accelerating water electrolysis.

The development of efficient and stable electrocatalysts for hydrogen evolution reaction (HER) is impending for the advancement of water-splitting. In this study, we developed a novel electrocatalyst consisting of highly dispersed Ru nanoclusters ameliorated by cobalt single atoms and N, S co-doped reduced graphene oxide (CoSA RuNC @NSG). Benefitted from the optimized electronic structure of the Ru nanoclusters induced by the adjacent single atomic Co and N, S co-doped RGO support, the electrocatalyst exhibits exceptional HER performance with overpotentials of 15 mV and 74 mV for achieving a current density of 10 mA cm-2 in alkaline and acidic water. The catalyst outperforms most noble metal-based HER electrocatalysts. Furthermore, the electrolyzer assembled with CoSA RuNC @NSG and RuO2 demonstrated an overall voltage of 1.56 V at 10 mA cm-2 and an excellent operational stability for over 25 h with almost no attenuation. Theoretical calculations also deduce its high HER activity demonstrated by the smaller reaction energy barrier due to the optimized electronic structure of Ru nanoclusters. This strategy involving the regulation of metal nanoparticles activity through flexible single atom and GO support could provide valuable insights into the design of high-performance and low-cost HER catalysts.