In-situ grown lead-free perovskite Cs3Bi2Br9 on porous Ta2O5 for boosted gas–solid phase CO2 photocatalytic conversion

Developing efficient photocatalysts for the conversion of CO 2 into value-added chemicals is considered as an ideal strategy to handle the energy crisis and environmental pollution. Among the numerous candidate materials, lead-free perovskite Cs 3 Bi 2 Br 9 has attracted significant research interests in CO 2 photoreduction because of its excellent reducing power and controllable product selectivity. In this work, we developed a novel Cs 3 Bi 2 Br 9 /Ta 2 O 5 composite via the in-situ growth of Cs 3 Bi 2 Br 9 on the porous Ta 2 O 5 , which exhibits excellent dual functionalities of CO 2 capture and conversion. The optimized sample T2 achieved a CO photoreduction yield of 413.45 μmol g −1  h −1 without adding any sacrificial agents, which is 4.7 and 22.3 times higher than that of pure Cs 3 Bi 2 Br 9 and Ta 2 O 5 , respectively. The markedly improved photocatalytic performance arises from a type-II heterojunction charge transfer pathway generated between Cs 3 Bi 2 Br 9 and Ta 2 O 5 , which drives the highly efficient separation and transfer of charge carriers, as confirmed by the enhanced photocurrent response and quenched PL intensity. Furthermore, the achieved composite also exhibited remarkable stability, as evidenced by the well-maintained structural integrity of the material after a 24-hour cycling test. This study provides key insights for developing novel lead-free perovskite-based photocatalysts, which has significant scientific and application value for achieving carbon neutrality goals.