Recent Advances in Electrocatalysts for Water Splitting: Fundamental Mechanism, Material Design and Challenges in Performance

Abstract

Electrochemical water splitting is a viable method for producing hydrogen (H2) sustainably and a crucial part of clean energy technology. However, the slow kinetics of the hydrogen evolution reaction (HER), especially the oxygen evolution reaction (OER), limit its effectiveness, making the development of effective electrocatalysts necessary to lower overpotential and increase reaction rates.[9,22] This overview outlines the fundamentals of water splitting, with a focusing on mechanism of HER and OER.. Noble metal catalysts—such as platinum for HER and Iridium or Ruthenium oxides for OER—serve as benchmarks because of their higher activity but are constrained by their high cost and scarcity.[6,21] As a result, considerable efforts have focused on earth-abundant alternatives that balance performance and cost, such as transition metal oxides, sulfides, carbides, and nitrides. Key design strategies, including defect engineering, heterostructure generation, nanostructuring, and electronic structure manipulation, are emphasised for their role in boosting active site density and optimizing adsorption properties to enhance catalytic efficiency. Advances in computational modelling have enabled rational catalyst design. Despite these advances, challenges such as gas crossover, high overpotentials, catalyst degradation, and scalability remain. To achieve effective and large-scale green hydrogen production, these challenges must be addressed through better materials and system design.