This review summarizes recent advances in nanostructured oxide photoelectrocatalysts for water splitting. The focus is on metal oxides such as Fe₂O₃, ZnO, CuO, and Co₃O₄ as photoelectrodes for photoelectrochemical (PEC) water splitting, along with strategies to enhance their performance, including morphological engineering, heterojunctions, and doping techniques. The review highlights the importance of these materials in generating hydrogen as a clean and sustainable energy source. Key challenges include low electrical conductivity, slow oxygen evolution kinetics, and short hole diffusion lengths in hematite-based photoanodes. To address these issues, various strategies have been explored, such as nanostructuring, heterojunction formation, and doping. For example, nanostructured hematite (Fe₂O₃) with improved morphology and heterojunctions has shown enhanced photoelectrochemical performance. Doping with elements like Ti, Zn, Sn, and Nb has also been shown to improve charge carrier mobility and reduce recombination. Additionally, the use of co-catalysts such as NiFeOₓ and Co₃O₄ has been effective in enhancing the efficiency of oxygen evolution. Copper-based oxides, such as CuO, have also been investigated for their potential in PEC water splitting, with morphological control and nanostructuring playing a key role in improving performance. Overall, the review emphasizes the importance of optimizing the structure, composition, and surface properties of oxide photoelectrodes to achieve efficient and stable water splitting for hydrogen production.This review summarizes recent advances in nanostructured oxide photoelectrocatalysts for water splitting. The focus is on metal oxides such as Fe₂O₃, ZnO, CuO, and Co₃O₄ as photoelectrodes for photoelectrochemical (PEC) water splitting, along with strategies to enhance their performance, including morphological engineering, heterojunctions, and doping techniques. The review highlights the importance of these materials in generating hydrogen as a clean and sustainable energy source. Key challenges include low electrical conductivity, slow oxygen evolution kinetics, and short hole diffusion lengths in hematite-based photoanodes. To address these issues, various strategies have been explored, such as nanostructuring, heterojunction formation, and doping. For example, nanostructured hematite (Fe₂O₃) with improved morphology and heterojunctions has shown enhanced photoelectrochemical performance. Doping with elements like Ti, Zn, Sn, and Nb has also been shown to improve charge carrier mobility and reduce recombination. Additionally, the use of co-catalysts such as NiFeOₓ and Co₃O₄ has been effective in enhancing the efficiency of oxygen evolution. Copper-based oxides, such as CuO, have also been investigated for their potential in PEC water splitting, with morphological control and nanostructuring playing a key role in improving performance. Overall, the review emphasizes the importance of optimizing the structure, composition, and surface properties of oxide photoelectrodes to achieve efficient and stable water splitting for hydrogen production.