Photoreforming of Organic Waste into Hydrogen: Catalyst Design, Feedstock Valorization, and Future Perspectives

Photoreforming is an emerging photocatalytic process that converts organic waste into hydrogen H2 using solar energy, offering a dual solution for waste valorization and sustainable fuel production. This review comprehensively examines the fundamental mechanisms of photoreforming, emphasizing the critical role of photocatalyst design in optimizing hydrogen evolution. Key criteria for effective photocatalysts including suitable band edge positions, broad spectrum solar absorption, and photostability are systematically analyzed alongside advances in heterojunction engineering and defect modulation. The review further explores diverse waste-derived feedstocks, such as biomass: alcohols, saccharides, lignin and plastics: PET, PLA, polyolefins, highlighting substrate, specific challenges and pretreatment strategies. Despite progress, challenges like catalyst deactivation, limited visible-light utilization, and scalability persist. Future directions advocate for robust photocatalyst engineering, mechanistic insights into charge dynamics, and scalable reactor designs to realize photoreforming’s potential as a sustainable hydrogen production technology.