Semiconductor photocatalysis is a highly active research area with a focus on enhancing the photocatalytic activity of materials like Fe2O3 and g-C3N4. Various strategies such as surface modification, composite materials, and doping are being explored to improve efficiency. Coupling different semiconductors leads to the creation of magnetic composite materials that show enhanced visible light response and improved charge carrier separation. Additionally, post-grafting of aromatic rings into g-C3N4 has proven effective in enhancing its photocatalytic efficiency, paving the way for novel composite photocatalysts. The article also discusses the development of a visible-light-driven photocatalytic system involving Pd nanoparticles on g-C3N4-imine-functionalized TiO2 nanoparticles for efficient hydrogenation reactions. This system offers a promising approach for hydrogenation processes, addressing limitations associated with traditional hydrogen donors and enhancing overall efficiency in organic synthesis.