Simultaneous Hydrogen Production and Pollutant Transformation Through Dual‐Functional Photocatalytic Reactions

Photocatalysis provides a direct solar‐driven route for addressing two urgent global needs, clean water and clean energy. Classical research treats pollutant degradation and hydrogen production as separate domains, with environmental photocatalysis focused on mineralization and hydrogen studies centered on water splitting. This perspective reframes photocatalytic systems as dual‐function redox platforms in which pollutants serve not only as electron donors but as reactive substrates capable of selective transformation while supporting hydrogen evolution. We established the mechanistic basis for this coupling, examining band energetics, hole‐driven oxidation, and the kinetic competition between proton reduction and oxygen reduction. Real water matrices introduce additional pathways shaped by natural organic matter, common anion/cations, turbidity, and microbial activity, which shift redox balance and influence selectivity. Recent advances in catalyst design, co‐catalyst engineering, and structured reactors have created new opportunities for guided oxidative pathways and stable hydrogen evolution. Building on these developments, we highlight emerging co‐valorization strategies that produce hydrogen while also converting wastewater‐borne organics into useful intermediates such as aldehydes and acids. Finally, we propose evaluation metrics that capture redox partitioning, product selectivity, and performance under realistic conditions. This integrated perspective positions dual‐function photocatalysis as a promising foundation for circular water–energy systems.