Bulk and surface dual modification of nickel-cobalt spinel with ruthenium toward highly efficient overall water splitting

The development of highly active and stable bifunctional catalysts toward overall water splitting at large current densities through delicate control of composition and structure is a challenging work. Herein, we combined the Ru-doping of NiCo2O4 spinel (NCO) and the surface modification with Ru nanoparticles through rational design and controllable fabrication (NCRO) as a dual modification method to markedly enhance the overall water splitting. Benefiting from the structure advantages, the synergistic electronic effects and optimal binding strength of the reaction intermediates, the NCRO exhibited excellent performance for both hydrogen evolution reaction and oxygen evolution reaction in alkaline media. The density functional theory calculations suggest that the dual modification could enhanced water dissociation ability, optimized the adsorption energy of reaction intermediates and altered the energy level of the d band center.