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

<jats:title>Abstract</jats:title><jats:p>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 Cs<jats:sub>2</jats:sub>SnI<jats:sub>6</jats:sub> perovskite anchored with a new class of atomically dispersed Pt-I<jats:sub>3</jats:sub> species (PtSA/Cs<jats:sub>2</jats:sub>SnI<jats:sub>6</jats:sub>) for achieving the highly efficient photocatalytic hydrogen production in HI aqueous solution at room temperature. Particularly, we discover that Cs<jats:sub>2</jats:sub>SnI<jats:sub>6</jats:sub> in PtSA/Cs<jats:sub>2</jats:sub>SnI<jats:sub>6</jats:sub> 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/Cs<jats:sub>2</jats:sub>SnI<jats:sub>6</jats:sub> catalyst shows a superb photocatalytic activity for hydrogen production with a record turnover frequency of 70.6 h<jats:sup>−1</jats:sup><jats:italic>per</jats:italic> Pt, about 176.5 times greater than that of Pt nanoparticles supported Cs<jats:sub>2</jats:sub>SnI<jats:sub>6</jats:sub> perovskite, along with superior cycling durability. Charge-carrier dynamics studies in combination with theory calculations reveal that the dramatically boosted photocatalytic performance on PtSA/Cs<jats:sub>2</jats:sub>SnI<jats:sub>6</jats:sub> originates from both unique coordination structure and electronic property of Pt-I<jats:sub>3</jats:sub> 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.</jats:p>