LAUSR

Heterostructures of metal halide perovskites and TiOx are efficient photocatalytic materials owing to the combination of the advantages of each compound, specifically the high absorption coefficients and long charge-carrier lifetimes of perovskites, and efficient photocatalytic activity of TiOx. However, chemical reduction of CO2 using PNC/TiOx heterostructures without organic solvents has not been reported yet. Here, we report the first solvent-free reduction of CO2 using amorphous TiOx with embedded colloidal perovskite nanocrystals (PNCs). The combination was obtained by carrying out hydrolysis of titanium butoxide (TBOT) on the PNC surface without high-temperature calcination. We proposed a mechanism involving photoexcited electrons being transferred from PNCs to TBOT, enabling photocatalytic reactions using TiOx under visible-light excitation. We demonstrated efficient visible-light-driven photocatalytic reactions at PNC/TiOx interfaces, specifically with a CO production rate of 30.43 μmol g-1 h-1 and accelerated degradation of organic pollutants under natural sunlight. Our work has provided a simple path toward both efficient CO2 reduction and photocatalytic degradation of organic dyes.