Review of d-band electron modulation in transition metals for water electrolysis

In the context of the urgent global transition toward clean and renewable energy, electrocatalytic water splitting for hydrogen production has gained increasing significance. The oxygen evolution reaction (OER), as a critical half-reaction in this process, remains constrained by high energy consumption and elevated material costs. The research of hydrogen production by water electrolysis is of great significance in promoting the development of hydrogen energy. This review comprehensively summarizes recent advances in transition metal-based OER catalysts, including metal–organic frameworks (MOFs), perovskites, layered double hydroxides (LDHs), high-entropy alloys (HEAs), and transition metal carbides (TMCs). Special emphasis is placed on the modulation of active metal electronic states, interface engineering, and morphology control, alongside a systematic discussion of state-of-the-art material design and synthesis strategies. Building upon a critical analysis of prior research, this work provides insightful perspectives on the rational design of transition metal-based OER catalysts, aiming to guide future developments in high-performance, low-cost electrocatalytic materials for sustainable hydrogen production.