Review of single-atom electrocatalysts for hydrogen and oxygen evolution reactions from water-splitting

Electrocatalysis has gained significant research attention due to its potential for sustainable and renewable energy production. Single-atom electrocatalysts (SACs) have emerged as a promising solution, leveraging metal atoms to facilitate electrocatalytic reactions with enhanced stability, reactivity, and selectivity. This review provides a comprehensive overview of the latest advancements in SACs for water splitting. It focuses on advanced synthesis methods, novel characterization techniques, and their applications in hydrogen and oxygen evolution reactions. Furthermore, we investigated the impact of structural engineering parameters, such as binding modes, coordination numbers, and dispersion tendencies, on electrocatalytic performance. We identified key challenges and opportunities for designing more selective, active, stable, and cost-effective SACs for energy conversion by analyzing associated mechanisms and summarizing recent experimental findings. The key challenges of SACs include scalability, stability, cost-effectiveness, mass transfer limitations, characterization, and standardization. These challenges can be addressed by developing scalable synthesis methods, designing stable and durable SACs, exploring earth-abundant metals, optimizing mass transfer, and establishing standardized characterization methods. The insights presented in this review pave the way for developing next-generation electrocatalysts for water splitting.