Single-atom Pt-I3 sites on all-inorganic Cs2SnI6 perovskite for efficient photocatalytic hydrogen production

Organic-inorganic lead halide perovskites are a new class of semiconductor materials with great potential in photocatalytic hydrogen production, however, their development is greatly plagued by their low photocatalytic activity, instability of organic component and lead toxicity in particular. Herein, we report an anti-dissolution environmentally friendly Cs₂SnI₆ perovskite anchored with a new class of atomically dispersed Pt-I₃ species (PtSA/Cs₂SnI₆) for achieving the highly efficient photocatalytic hydrogen production in HI aqueous solution at room temperature. Particularly, we discover that Cs₂SnI₆ in PtSA/Cs₂SnI₆ has a greatly enhanced tolerance towards HI aqueous solution, which is very important for achieving excellent photocatalytic stability in perovskite-based HI splitting system. Remarkably, the PtSA/Cs₂SnI₆ catalyst shows a superb photocatalytic activity for hydrogen production with a record turnover frequency of 70.6 h^-1 per Pt, about 176.5 times greater than that of Pt nanoparticles supported Cs₂SnI₆ perovskite, along with superior cycling durability. Charge-carrier dynamics studies in combination with theory calculations reveal that the dramatically boosted photocatalytic performance on PtSA/Cs₂SnI₆ originates from both unique coordination structure and electronic property of Pt-I₃ sites, and strong metal-support interaction effect that can not only greatly promote the charge separation and transfer, but also substantially reduce the energy barrier for hydrogen production. This work opens a new way for stimulating more research on perovskite composite materials for efficient hydrogen production.