Recent progress in ion-modified TiO₂ for enhanced photocatalytic hydrogen production has been reviewed, focusing on strategies to improve the efficiency of hydrogen generation through water splitting under solar light. TiO₂, a widely studied semiconductor photocatalyst, has limitations such as a wide bandgap and rapid recombination of photogenerated charge carriers, which hinder its effectiveness in visible light. To address these issues, various ion modification techniques have been explored, including metal doping, metal nanoparticle (NP) deposition, and nonmetal doping. These methods aim to narrow the bandgap, introduce defect states, and enhance the separation and transfer of charge carriers, thereby improving the photocatalytic performance of TiO₂. Metal doping, particularly with transition metals like Cu, Fe, and Cr, has been shown to reduce the bandgap of TiO₂, enabling it to absorb visible light and increase hydrogen production efficiency. For example, Cu-doped TiO₂ with 0.5 mol% doping exhibited significantly higher hydrogen evolution rates under UV and UV-B irradiation. Similarly, Fe-doped TiO₂ showed enhanced photocatalytic activity, with hydrogen production rates increasing under both UV and visible light. The optimal Fe concentration was found to be around 0.15–0.5 wt%, which improved the separation of electron-hole pairs and enhanced the overall efficiency of hydrogen production. Nonmetal doping, such as with Sr and Ru, has also been effective in modifying the electronic structure of TiO₂, increasing its surface area, and tuning its bandgap to enhance visible light absorption. Additionally, the incorporation of noble metal NPs, such as Au and Ag, has been shown to extend the light absorption range of TiO₂ to the visible and near-infrared regions through localized surface plasmon resonance (LSPR). These NPs act as both sensitizers and co-catalysts, facilitating electron injection into the conduction band of TiO₂ and improving charge separation and transfer. The review highlights the importance of optimizing the concentration and type of dopants to achieve the best photocatalytic performance. Metal NPs, when deposited on TiO₂, can form Schottky junctions that enhance charge separation and reduce recombination rates. The synergistic effects of different modification strategies, such as combining metal doping with NP deposition, have been shown to significantly improve the efficiency of hydrogen production from water splitting under solar light. Overall, ion-modified TiO₂ photocatalysts represent a promising avenue for advancing the efficiency and practicality of solar-driven hydrogen production.Recent progress in ion-modified TiO₂ for enhanced photocatalytic hydrogen production has been reviewed, focusing on strategies to improve the efficiency of hydrogen generation through water splitting under solar light. TiO₂, a widely studied semiconductor photocatalyst, has limitations such as a wide bandgap and rapid recombination of photogenerated charge carriers, which hinder its effectiveness in visible light. To address these issues, various ion modification techniques have been explored, including metal doping, metal nanoparticle (NP) deposition, and nonmetal doping. These methods aim to narrow the bandgap, introduce defect states, and enhance the separation and transfer of charge carriers, thereby improving the photocatalytic performance of TiO₂. Metal doping, particularly with transition metals like Cu, Fe, and Cr, has been shown to reduce the bandgap of TiO₂, enabling it to absorb visible light and increase hydrogen production efficiency. For example, Cu-doped TiO₂ with 0.5 mol% doping exhibited significantly higher hydrogen evolution rates under UV and UV-B irradiation. Similarly, Fe-doped TiO₂ showed enhanced photocatalytic activity, with hydrogen production rates increasing under both UV and visible light. The optimal Fe concentration was found to be around 0.15–0.5 wt%, which improved the separation of electron-hole pairs and enhanced the overall efficiency of hydrogen production. Nonmetal doping, such as with Sr and Ru, has also been effective in modifying the electronic structure of TiO₂, increasing its surface area, and tuning its bandgap to enhance visible light absorption. Additionally, the incorporation of noble metal NPs, such as Au and Ag, has been shown to extend the light absorption range of TiO₂ to the visible and near-infrared regions through localized surface plasmon resonance (LSPR). These NPs act as both sensitizers and co-catalysts, facilitating electron injection into the conduction band of TiO₂ and improving charge separation and transfer. The review highlights the importance of optimizing the concentration and type of dopants to achieve the best photocatalytic performance. Metal NPs, when deposited on TiO₂, can form Schottky junctions that enhance charge separation and reduce recombination rates. The synergistic effects of different modification strategies, such as combining metal doping with NP deposition, have been shown to significantly improve the efficiency of hydrogen production from water splitting under solar light. Overall, ion-modified TiO₂ photocatalysts represent a promising avenue for advancing the efficiency and practicality of solar-driven hydrogen production.