Transition metal phosphides for efficient hydrogen evolution: Synthesis, multiscale regulation, and industrial prospects

Achieving scalable green hydrogen generation through water electrolysis hinges on discovering affordable yet highly effective hydrogen evolution reaction (HER) catalysts to replace traditional Pt-based options. Transition metal phosphides (TMPs) have risen as attractive electrocatalysts, featuring tunable electronic structures, excellent conductivity, and robust stability. This review systematically examines recent advances in TMPs-based HER catalysts, bridging fundamental research and industrial applications. We first elucidate structure-activity relationships and HER mechanisms, then critically evaluate scalable synthesis methods. Multiscale optimization strategies are comprehensively discussed, including atomic-scale engineering, nanostructural design, and hybrid composites, with experimental-theoretical correlations quantifying performance enhancements. Notably, we highlight breakthroughs in achieving industrial current densities (≥500 mA cm−2) while maintaining stability. Key challenges in in-situ characterization, durability, and practical deployment are identified, with targeted solutions proposed to accelerate commercialization. This work provides critical insights for designing next-generation HER electrocatalysts to enable sustainable hydrogen production at scale.