Novel synthesis of ultra-low Pt-loaded TiO2 catalysts for efficient photocatalytic H2 evolution: a controllable photoreduction strategy

While noble metal single atoms (SAs)/semiconductor photocatalysts offer outstanding catalytic performance, challenges related to dosage and stability limit their broader application. In this study, we present a controlled photoreduction strategy that leverages synergistic photoreduction conditions, steric hindrance, and complexation to significantly enhance both activity and stability with an ultra-low Pt loading. The optimized Pt/TiO 2 catalyst (0.0063 wt% Pt) exhibits a 73-fold increase in photocatalytic activity, achieving a Pt mass activity of 6.24 mol/g/h. XPS analysis and DFT calculations reveal that Pt atoms are deposited on TiO 2 via strong interactions resembling an O-Pt-O bond, effectively preventing the migration and aggregation of highly dispersed Pt SAs, thereby significantly improving catalyst stability. Additionally, the ΔG H * for Pt 2+ SAs is nearly 0 (−0.002 eV), enabling rapid H adsorption and H 2 desorption, which imparts the catalyst with exceptional catalytic performance. This study paves the way for the development of catalysts with minimal precious metal content, enhanced efficiency, and extended stability.