Research Progress on Mott-Schottky Hydrogen Evolution Catalysts Based on Metal/Transition Metal Compounds

Hydrogen energy as an ideal energy carrier holds significant importance for promoting the transformation of energy structures. Electrolytic water splitting technology is crucial to achieve large-scale hydrogen production. The hydrogen evolution activity, stability and cost of catalysts are the key factors for its development. Transition metal compounds (TMCs) become popular candidates to replace noble-metal catalysts due to their low costs, abundant resources and tunable electronic structures. Mott-Schottky (M-S) junctions, constructed between transition metal compound semiconductors and metals, are considered to be an effective strategy to enhance catalytic activity. This review summarizes the research progress of metal/TMCs M-S junction catalysts, including their classification (metal/oxides, sulfides, selenides, phosphides, and nitrides, etc.), construction strategies (hydrothermal method, in-situ reduction, and phosphidation treatment, etc.), and enhancement mechanisms. Research findings indicate that the M-S junction optimizes their electronic structure and hydrogen adsorption free energy through interfacial charge rearrangement and their formation of built-in electric fields, thereby promoting charge separation and transfer and significantly enhancing hydrogen evolution activity. In addition, the review discusses the key issues that still need in-depth exploration and clarification regarding M-S junction catalysts, and provides an outlook on future research directions and development trends. It aims to offer theoretical guidance for design of efficient and cost-effective hydrogen evolution electrocatalysts and to promote sustainable development of hydrogen energy technology.