Photocatalytic CO2 Reduction Coupled with Oxidation of Benzyl Alcohol over CsPbBr3@PANI Nanocomposites

Herein, we successfully prepare conductive polyaniline (PANI)-encapsulated CsPbBr₃ perovskite nanocrystals (PNCs) that demonstrate much improved photocatalytic performance and stability toward the CO₂ reduction reaction (CRR) coupled with oxidation of benzyl alcohol (BA) to benzaldehyde. Due to the acid-base interaction between CO₂ and PANI, CO₂ molecules are selectively adsorbed on PANI in the form of carbamate. As a result, the rate of production of CO (r_CO) reaches 26.1 μmol g^-1 h^-1 with a selectivity of 98.1%, which is in good agreement with the rate of oxidation (∼27.0 μmol g^-1 h^-1) of BA. Such a high reduction/oxidation rate is enabled by the fast electron transfer (∼2.2 ps) from PNCs to PANI, as revealed by femtosecond transient absorption spectroscopy. Moreover, because of the benefit of the encapsulation of PANI, no significant decrease in r_CO is observed in a 10 h CRR test. This work offers insight into how to simultaneously achieve improved photocatalytic performance and stability of CsPbX₃ PNCs.