Epitaxial Growth of Nickel Oxide on Lattice-Matched Tungsten Nitride Support for Electrocatalytic Hydrogen Evolution

Constructing heterostructures by using different earth-abundant materials is a practical approach for comprehensively integrating their individual advantages to achieve exceptional electrocatalytic activity. This approach is particularly critical for substituting noble metals in water splitting technologies. However, lattice mismatch can induce interfacial stress in heterostructures, leading to sluggish kinetics for electrocatalytic hydrogen evolution. Herein, we develop a heterostructured electrocatalyst, where the NiO nanophase is epitaxially grown on the rationally selected WN support for its highly matched lattice parameters. Benefiting from the relieved interfacial stress, charge transfer between NiO and WN can be facilitated. Besides, the intermediate adsorption on the heterostructure is simultaneously modulated for the interfacial charge redistribution. Consequently, NiO/WN exhibits a remarkable electrocatalytic activity, requiring only an overpotential of 78 mV to deliver 10 mA cm^-2 in an alkaline medium. This strategy of epitaxially growing nanophases on lattice-matched supports provides a promising paradigm for the design of advanced heterostructured electrocatalysts.