Review of Water Splitting Electrolysis over Cobalt Oxide Nanomaterials

Given the recognition of hydrogen fuel as a future energy source, the demand for green hydrogen production necessitates rational electrode designs. Achieving stable durability and high efficiency in electrode fabrication requires a logical combination of substrate and catalyst materials. Cobalt oxide has emerged as a promising catalyst that has garnered significant attention due to its potential to enhance catalytic activity and robustness. In this study, we present a systematic approach to improve the water splitting activity of Co3O4 through morphology control, defect engineering, doping, and heterostructure integration. This study investigates the intrinsic properties of Co3O4, from the atomic to the crystal level, that govern its interfacial activity and synergistic behavior with other materials. These properties significantly influence the surface reaction dynamics of Co3O4, ultimately impacting the kinetics of water splitting. Furthermore, various synthesis routes have been developed to provide a comprehensive perspective on the direct deposition of Co3O4 nanostructures on different conductive substrates. This review encompasses diverse electrode fabrication strategies aimed at optimizing Co3O4 activity. The connection between these strategies offers a complete electrode design pathway, thereby fostering the sustainable development of high-efficiency electrodes for hydrogen production.