Seamless separation of OHad and H-ad on a Ni-O catalyst toward exceptional alkaline hydrogen evolution

Seamless separation of intermediates (OHad and H-ad) to different active sites at the atomic scale is realized on a Ni-O catalyst that is functionalized with low-coordinated oxygen and abundant vacancies. During alkaline hydrogen evolution reaction (HER), the former enables active states for H-ad adsorption/desorption; meanwhile, nearby Ni delta+ vacancies allow an optimal interaction with OHad. Consequently, such a synergistic action significantly expedites water dissociation and HER kinetics on the Ni-O catalyst with exceptional activity approaching that of the benchmark platinum electrocatalyst. This work presents a significant advance and offers new insights in designing non-precious metal oxides toward alkaline HER.