Perovskite-mediated lattice compatibility in BaTiO3/CsPbBr3 heterostructures for photocatalytic CO2 reduction

Heterojunction engineering significantly enhances photocatalytic CO 2 reduction performance. However, a large lattice mismatch in heterostructures hinders photocatalytic reaction by forming extensive grain boundaries, inefficient interfaces, and sluggish interfacial charge transfer. Metal halide perovskites, featuring soft lattices induced by weak ionic metal-halide bonds, offer effective solutions to alleviate such mismatches. Herein, we fabricate BaTiO 3 /CsPbBr 3 photocatalysts with a precisely engineered type-II heterojunction. Notably, the BaTiO 3 /CsPbBr 3 heterostructure achieves a CO formation rate of 17.3 μmol∙g −1  h −1 — 5.2-fold and 2.3-fold higher than pristine BaTiO 3 (3.3 μmol∙g −1  h −1 ) and CsPbBr 3 (7.6 μmol∙g −1  h −1 ), respectively. This improvement stems from the synergistic effect of enhanced light absorption and charge separation. This work provides fundamental insights for developing high-performance heterojunction photocatalysts.