Phosphorus and Molybdenum Codoped Ru/RuO ₂ Heterostructures for Alkaline Overall Water Splitting

Bifunctional electrocatalysts for overall water splitting (OWS) is critical for sustainable hydrogen production but remains challenging due to the sluggish kinetics and leaching of metal ions. Herein, we present a kind of phosphorus and molybdenum codoped ruthenium and ruthenium oxides heterostructure (P,Mo_0.1-Ru/RuO₂) as a highly efficient bifunctional electrocatalyst for alkaline OWS. The incorporation of P facilitates the electron transfer from P to Ru, leading to the partial reduction of RuO₂ to metallic Ru. Moreover, the reduced oxidation of Ru suppresses the dissolution of RuO₂, favoring the structural stability. In alkaline media, P,Mo_0.1-Ru/RuO₂ demonstrates enhanced hydrogen evolution and oxygen evolution activities, requiring overpotentials of only 61 and 230 mV, respectively, to achieve a current density of 10 mA cm^- ². When employed as anode and cathode for OWS, the P,Mo_0.1-Ru/RuO₂ catalyst enabled a low cell voltage of 1.50 V at 10 mA cm^- ², along with an enhanced electrochemical stability. These results highlight the synergistic effect of anion and cation codoping in enhancing electrocatalytic performance, offering a promising strategy for the design of advanced bifunctional catalysts for sustainable hydrogen production.