Efficient electron transport at the perovskite nanodots interface facilitates CO₂ photoreduction

How to achieve controllable preparation of heterostructure and in-situ optimize the interface and internal electron transfer by a fast and economic synthesis method has become a big challenge in the practical application of photocatalysis. Herein, an island-shaped SrTiO₃ (STO) perovskite nanodots and TiO₂ (T) compounded S-scheme SrTiO₃/TiO₂ (ST) heterostructure was successfully developed. During the millisecond reaction process, the decomposed Sr²⁺ penetrated into the TiO₂ lattice causing the lattice expansion and inducing local atomic rearrangements, resulting in the generation of STO phase. Owing to the synergy of the efficient electron transport at the perovskite nanodots interface and the stronger reduction capacity, the performance of the optimized ST1 sample is greatly improved to 86.90 μmol g^-1 for CO₂-to-CO and 21.31 μmol g^-1 for CO₂-to-CH₄. The utilization of electrons reached up to 119.74 μmol g^-1 h^-1, which was 3.13 times higher than that of T. Detailed characterizations and density functional theory (DFT) calculations proof that the formation of intermediates HCOO^- and CO₃^2- is the key to the performance improvement critically. Overall, this work originally reports a feasible strategy for flame synthesis of S-scheme heterostructure photocatalyst.