An effective bimetallic oxide catalyst of RuO₂-Co₃O₄ for alkaline overall water splitting

The rational design of effective bifunctional electrocatalysts is of paramount importance for overall water-splitting technology in sustainable energy conversion. Herein, bimetallic oxide catalysts (RuO₂-Co₃O₄) derived from Ru combined MOF-derivatives (MOF = metal-organic framework) were demonstrated effective for overall water splitting in an alkaline solution, owing to the combined merits such as the two-dimensional interconnected network structure, the synergetic coupling effects and increased chemical stability. The as-prepared RuO₂-Co₃O₄ only requires an overpotential of 260 mV for oxygen evolution and 75 mV for hydrogen evolution at 10 mA/cm² in 1 M KOH solution; a low cell voltage of 1.54 V was required to reach the kinetic current density of 10 mA/cm² for the water electrolysis when supporting on glass carbon electrode, and very good stability for 40 h was observed. Experimental and theoretical results demonstrated the electronic structure optimization of bimetallic RuO₂-Co₃O₄ compared to the individual metal oxide, which promoted interface charges redistribution and the d-band center downshift, resulting in increased activity and stability for water-splitting reactions. This work provides a feasible approach for developing bimetallic oxides for application in energy-relevant electrocatalysis reactions.