Seamless separation of OHad and Had on a Ni–O catalyst toward exceptional alkaline hydrogen evolution

Abstract

Seamless separation of intermediates (OH_ad 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^δ+ vacancies allow an optimal interaction with OH_ad. 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.