Multi-interface engineering of nickel-based electrocatalysts for alkaline hydrogen evolution reaction

High gravimetric energy density and zero carbon emission of hydrogen have motivated hydrogen energy to be an attractive alternative to fossil fuels. Electrochemical water splitting in alkaline medium, driven by green electricity from renewable sources, has been mentioned as a potential solution for sustainable hydrogen production. Hydrogen evolution reaction (HER), as a cathodic half-reaction of water splitting, requires additional overpotential to obtain protons via water adsorption/dissociation, suffering from slow kinetics in alkaline solution. Robust and active nickel (Ni)-based electrocatalyst is a promising candidate for achieving precious-metal comparable performance owing to its platinum-like electronic structures with more efficient electrical power consumption. Various modification strategies have been explored on Ni-based catalysts, among which multi-interface engineering is one of the most effective routines to optimize both the intrinsic activity of Ni-based electrocatalysts and the extrinsic stacked component limitations. Herein, we systematically summarize the recent progress of multi-interface engineering of Ni-based electrocatalysts to improve their alkaline HER catalytic activity. The origin of sluggish alkaline HER kinetics is first discussed. Subsequently, three kinds of interfaces, geometrically and reactively, conductive substrate/electrocatalyst interface, electrocatalyst internal heterointerface, and electrocatalyst/electrolyte interface, were cataloged and discussed on their contribution mechanisms toward alkaline HER. Particular focuses lie on the microstructural and electronic modulation of key intermediates with energetically favorable adsorption/desorption behaviors via rationally designed interfaces. Finally, challenges and perspectives for multi-interface engineering are discussed. We hope that this review will be inspiring and beneficial for the exploration of efficient Ni-based electrocatalysts for alkaline water electrolysis.