This review provides an overview of significant innovations in photocatalysts for hydrogen evolution, focusing on selection criteria, photocatalytic modifications, and mechanisms. Various semiconductors such as TiO₂, g-C₃N₄, graphene, sulfide, oxide, nitride, oxysulfide, oxynitrides, and cocatalyst-based photocatalysts are examined. Techniques to enhance metal and nonmetal compatibility to boost photoactivity under visible light are discussed, including the development of heterojunctions (type I, II, and III) and Z-systems. The importance of reaction chemistry, mass transfer, kinetics, light diffusion, and suitable light and photoreactors is highlighted to optimize sustainable hydrogen output efficiency and selectivity. The review also covers the thermodynamic aspects of water splitting, the selection of photocatalysts, and strategies to improve photocatalytic activity, such as surface refinement, heterojunction emergence, and Z-scheme and S-scheme systems. Specific materials like TiO₂, ZnO, WO₃, Fe₂O₃, CuO, Cu₂O, g-C₃N₄, and metal sulfides are detailed, along with their modifications and improvements to enhance photocatalytic performance.This review provides an overview of significant innovations in photocatalysts for hydrogen evolution, focusing on selection criteria, photocatalytic modifications, and mechanisms. Various semiconductors such as TiO₂, g-C₃N₄, graphene, sulfide, oxide, nitride, oxysulfide, oxynitrides, and cocatalyst-based photocatalysts are examined. Techniques to enhance metal and nonmetal compatibility to boost photoactivity under visible light are discussed, including the development of heterojunctions (type I, II, and III) and Z-systems. The importance of reaction chemistry, mass transfer, kinetics, light diffusion, and suitable light and photoreactors is highlighted to optimize sustainable hydrogen output efficiency and selectivity. The review also covers the thermodynamic aspects of water splitting, the selection of photocatalysts, and strategies to improve photocatalytic activity, such as surface refinement, heterojunction emergence, and Z-scheme and S-scheme systems. Specific materials like TiO₂, ZnO, WO₃, Fe₂O₃, CuO, Cu₂O, g-C₃N₄, and metal sulfides are detailed, along with their modifications and improvements to enhance photocatalytic performance.