A focused review on design aspects of noble-metal-free oxide-graphenaceous nanocomposites as electrocatalysts for direct seawater electrolysis

Hydrogen ( \({\text{H}}_{2}\) ) has emerged as an important energy resource to achieve sustainable carbon neutrality. While conventional \({\text{H}}_{2}\) generation methods rely on fossil fuels, the electrocatalytic water splitting driven by renewable energy offers a clean alternative. However, the scarcity of freshwater resources necessitates the development of seawater electrolysis (SWE), which relies on electrocatalysts for efficient H 2 evolution. This comprehensive review examines the state-of-the-art in \({\text{H}}_{2}\) generation from seawater using noble-metal-free oxide-graphene nanocomposites as electrocatalysts. This review systematically examines the fundamental principles governing direct SWE, with particular emphasis on thermodynamics, reaction kinetics, and the electrochemical mechanisms underlying the hydrogen evolution reaction, oxygen evolution reaction, and competing chlorine evolution reaction. The review critically evaluates catalyst design principles, namely, electronic structure, active site optimization, specific surface area, electrical conductivity, and chloride corrosion resistance that govern the performance of electrocatalysts in a harsh seawater environment. A comprehensive comparison of top-performing metal oxide-graphenaceous nanocomposites is presented, and practical challenges, including chloride-induced corrosion and system-level integration issues, as well as benchmarking criteria for commercialization, are discussed. Finally, suggestions for future research and development are given.