Strategic structural design of transition metal electrocatalysts for efficient water splitting: A comprehensive review

Electrochemical water splitting (EWS) is a pivotal method for sustainable hydrogen (H2) generation, yet it faces challenges due to limited accessibility and high costs associated with precious metal electrocatalysts. Efforts in research have thus been directed toward developing cost-effective alternatives to drive widespread adoption. Transition metals (TMs) emerge as promising candidates to replace noble metal-based electrocatalysts in EWS, offering abundance and affordability. This review surveys recent advancements and innovative methodologies in designing TM-based electrocatalysts, focusing on strategies such as defect engineering of MXene. This approach demonstrates considerable potential in enhancing EWS technology. Moreover, the review underscores the necessity of comprehending the fundamental mechanisms and activity-limiting factors inherent in EWS. It advocates for catalyst engineering strategies, integration of theoretical calculations, and modern in situ characterization techniques to facilitate the commercialization of electrocatalysts for sustainable hydrogen production. By integrating recent progress and ongoing challenges, this review seeks to present insights into the frontier of TM-based electrocatalysts and their role in advancing the field of EWS toward a more sustainable future. [Display omitted] •Diverse strategies for designing TM catalysts are comprehensively evaluated.•Detailed explanations of HER and OER mechanisms/ activity indicators are provided.•Defect engineering approaches in MXenes are briefly described.•Recommendations for developing commercial-grade catalysts are proposed.