Insights into the Influence of Anatase TiO₂ Facets on Marine Biomass Photoreforming Coupled with Hydrogen Evolution

Photocatalytic reforming of waste biomass provides a promising approach for the simultaneous clean energy production and resource recovery. Herein, we report the efficient coupling of hydrogen (H₂) evolution with the oxidation of waste chitin, achieving the coproduction of H₂ and value-added chemicals. Through systematic screening, anatase TiO₂ has been identified as the optimal material for the coupled photocatalytic system, with its reforming activity being closely associated with the production of hydroxyl radicals (^•OH). Based on this mechanism, TiO₂ dominated by {001} facets was successfully synthesized, achieving an H₂ evolution rate of 291.0 μmol·g^-1·h^-1. This performance represents significant enhancements of 42.2 and 5.0 times compared to TiO₂ dominated by {101} and {100} facets, respectively. This superior activity is attributed to the {001} facets, which facilitate the formation of ^•OH and enhance the adsorption of chitin. What is more, practical scalability was demonstrated by directly converting real-world crab shells into H₂ under mild conditions using a combined mechanical ball milling and photocatalytic reforming process. This work proposes an efficient and scalable strategy for marine waste reforming coupled with clean energy production and highlights the importance of facet engineering in designing photocatalysts for biomass valorization.