This review discusses the enhancement of photocatalytic activity in nanostructured metal oxide photocatalysts. Metal oxides, such as TiO₂, ZnO, WO₃, and others, are promising materials due to their excellent photosensitivity, chemical stability, non-toxicity, and biocompatibility. However, their efficiency is limited by their primary operation under UV light and the recombination of photogenerated electrons and holes. Strategies to enhance photocatalytic performance include structure or material modifications, such as doping with nonmetals or metals, surface modification, heterojunction formation, and nanostructuring. These approaches aim to improve charge separation, extend light absorption into the visible range, and reduce recombination rates. ZnO-based nanocomposites, in particular, have shown promise in environmental remediation, energy conversion, and biomedical applications. The review highlights recent advancements in ZnO-based photocatalysts, including their coupling with carbon-based materials like graphene oxide (GO) and reduced graphene oxide (rGO), which can enhance photocatalytic activity and reduce recombination. Other metal oxides, such as iron (III) oxide, niobium pentoxide, titanium dioxide, tungsten trioxide, and vanadium oxide, are also discussed for their photocatalytic properties and potential applications. The review emphasizes the importance of optimizing the structure, composition, and properties of metal oxide photocatalysts to improve their efficiency and effectiveness in various applications, including water purification, antimicrobial agents, air purification, and hydrogen production. Advanced characterization techniques are also discussed to understand and optimize the performance of these materials.This review discusses the enhancement of photocatalytic activity in nanostructured metal oxide photocatalysts. Metal oxides, such as TiO₂, ZnO, WO₃, and others, are promising materials due to their excellent photosensitivity, chemical stability, non-toxicity, and biocompatibility. However, their efficiency is limited by their primary operation under UV light and the recombination of photogenerated electrons and holes. Strategies to enhance photocatalytic performance include structure or material modifications, such as doping with nonmetals or metals, surface modification, heterojunction formation, and nanostructuring. These approaches aim to improve charge separation, extend light absorption into the visible range, and reduce recombination rates. ZnO-based nanocomposites, in particular, have shown promise in environmental remediation, energy conversion, and biomedical applications. The review highlights recent advancements in ZnO-based photocatalysts, including their coupling with carbon-based materials like graphene oxide (GO) and reduced graphene oxide (rGO), which can enhance photocatalytic activity and reduce recombination. Other metal oxides, such as iron (III) oxide, niobium pentoxide, titanium dioxide, tungsten trioxide, and vanadium oxide, are also discussed for their photocatalytic properties and potential applications. The review emphasizes the importance of optimizing the structure, composition, and properties of metal oxide photocatalysts to improve their efficiency and effectiveness in various applications, including water purification, antimicrobial agents, air purification, and hydrogen production. Advanced characterization techniques are also discussed to understand and optimize the performance of these materials.