Advances of Nanostructured Metal Oxide as Photoanode in Photoelectrochemical (PEC) Water Splitting Application

Research highlights;•Metal oxides nanostructures enable efficient PEC water splitting for hydrogen generation.•BiVO4 based photoanode shows efficient visible light absorption for water splitting.•Key strategies: doping, heterojunctions, and surface modifications.•Machine learning optimizes PEC catalysts and boosts research speed.•Co-catalysts enhance oxygen evolution and PEC cell performance.•Nanostructuring of photocatalysts improve PEC photocurrent density.AbstractWater splitting via photoelectrochemical (PEC) cells offers a promising route to generate hydrogen fuel using solar energy. Nanostructured metal oxides have emerged as leading candidates as photoelectrodes in photocatalytic H2 production due to their photo-electrochemical stability, large surface area, earth abundance, and suitable band gap energies. This review reports the recent advancements of nanostructured metal oxide as photoanodes in photoelectrochemical (PEC) water-splitting applications. This review focuses on recent advancements in metal oxide photoanodes, their synthesis methods, modification strategies, and performance in PEC water splitting. Critical materials such as TiO2, Fe2O3, WO3, and BiVO4 are discussed in detail, highlighting their strengths, limitations, and future research directions to enhance efficiency and stability. This review will give clear insight into the trends and the critical factors for efficient metal oxide photoelectrode to improve the photocatalytic effectiveness in generating hydrogen fuel as an alternative energy source in the future. Finally, this study emphasises the potential of incorporating machine learning methods into experimental workflows to accelerate the optimisation of electrocatalysis performance, representing a significant advancement in developing efficient and sustainable hydrogen production technologies.