Stable and Highly Active Single Atom Configurations for Photocatalytic H2 Generation

Abstract The employment of single atoms (SAs), especially Pt SAs, as co‐catalysts in photocatalytic H 2 generation has gained significant attention due to their exceptional efficiency. However, a major challenge in their application is the light‐induced agglomeration of these SAs into less active nanosized particles under photocatalytic conditions. This study addresses the stability and reactivity of Pt SAs on TiO 2 surfaces by investigating various post‐deposition annealing treatments in air, Ar, and Ar‐H 2 environments at different temperatures. It is described that annealing in an Ar‐H 2 atmosphere optimally stabilizes SA configurations, forming stable 2D rafts of assembled SAs ≈0.5–1 nm in diameter. These rafts not only resist light‐induced agglomeration but also exhibit significantly enhanced H 2 production efficiency. The findings reveal a promising approach to maintaining the high reactivity of Pt SAs while overcoming the critical challenge of their stability under photocatalytic conditions.