Dual-functional photocatalysis: bridging hydrogen production and environmental remediation – a review

Abstract

The convergence of global water pollution and the demand for clean energy has accelerated interest in photocatalytic systems capable of simultaneously generating hydrogen and degrading recalcitrant organic contaminants. Rather than treating wastewater and energy production as independent challenges, dual-functional photocatalysis offers a unified solar-driven strategy in which photogenerated electrons fuel hydrogen evolution. At the same time, holes and reactive oxygen species drive the mineralization of pollutants. This review explores recent advances in integrated photocatalytic platforms that transform wastewater from an environmental liability into a functional resource for sustainable hydrogen generation. Emphasis is placed on mechanistic coupling between redox reactions, highlighting how band alignment, interfacial charge transfer, and heterojunction architecture govern the balance between hydrogen selectivity and oxidative degradation. Key catalyst engineering strategies, including defect modulation, co-catalyst loading, and Z-scheme and S-scheme heterojunctions, are critically examined across systems targeting pharmaceuticals, dyes, and microplastics. Beyond material innovation, the review evaluates the practical implications of using pollutants as sacrificial electron donors, including trade-offs related to mineralization, catalyst stability, and the complexity of real wastewater. By integrating mechanistic insight with application-oriented assessment, this work provides a roadmap for designing robust photocatalytic systems that bridge environmental remediation and clean energy production, advancing circular economy principles and multiple sustainable development goals.