Regulating the Heterostructure of Metal/Oxide toward the Enhanced Hydrogen Evolution Reaction

Designing a metal/oxide hybrid is an effective approach in facilitating water dissociation (Volmer step) for the hydrogen evolution reaction (HER) in alkaline solutions. It is critical to tailor the metal/oxide heterostructure and find out the structure–activity relationship. Herein, the tuning of the Ni/NiO interfacial structure and its influence on the HER activity were systematically studied. Ni/NiO-cp was prepared by controlling the nucleation rate and orientational growth of NiO. Plentiful wormlike NiO nanoflakes were produced on interlaced Ni nanosheets. Ni/NiO-cp possessed abundant oxygen vacancies, a high content of surface hydroxyl species, and numerous metal/oxide interfaces. Not only the adsorption of H2O molecules was accelerated but also the electrolyte penetration and proton transport were both facilitated. As a result, the HER overpotential to deliver 10 mA cm–2 was significantly reduced by 124 mV as compared with that of the unmodified counterpart (as-deposited Ni). The performance of Ni/NiO-cp was superior to that of Pt/C at high currents (>100 mA cm–2). The facile regulation technique and the structure–activity relationship reported here are helpful for the discovery of low-cost and efficient HER catalysts.