Strong coupling effects at the interfacial sites of a heterojunction formed by 0D/2D Ir quantum dots and TiO2 ultrathin nanosheets for robust photocatalytic H2 production

In this study, we designed a novel two-dimensional ulrathin TiO2 nanosheet structure decorated with Ir quantum dots via an immersion method for photocatalytic H2 production. The resulting Ir-modified TiO2 (Ir/TiO2) possess excellent and stable photocatalytic H2 production activity, with the H2 production rate of 3% Ir/TiO2 being 21 times that of pure TiO2. This enhanced photocatalytic activity is attributed to the interface sites formed between the two-dimensional ultrathin structure and Ir quantum dots, which increase visible light absorption, accelerate the separation of photogenerated charges, and evidently lower the reaction barrier. Additionally, the unique twodimensional nanosheet structure of TiO2 provides a high surface area for optimal dispersion of Ir quantum dots. The size of Ir nanoparticles increased only slightly, from 1.1 nm to 2.1 nm, after five cycles, indicating high stability. This work presents a potential strategy for designing 0D/2D photocatalysts for efficient H2 production.