Synthesis and CO2 Photoreduction of Lead-Free Cesium Bismuth Halide Perovskite Nanocrystals

The photoreduction of CO2 into renewable fuels is a promising approach to solve the global energy and environmental crisis. All-inorganic bismuth (Bi) halide perovskite nanocrystals (NCs) have emerged as an appealing photocatalyst for visible-light-driven CO2 reduction, but they still have low photocatalytic activity. Herein, a set of lead-free and stable Cs3Bi2X9 (X = Cl, Cl0.5Br0.5, Br, Br0.5I0.5, I) perovskite NCs were explored for the photocatalytic reduction of CO2 to CO at the gas–solid interface. In all of the recorded perovskite NCs, the as-synthesized Cs3Bi2(Br0.5I0.5)9 showed the highest efficiency of CO2-to-CO conversion producing 54 μmol g–1 of CO yield under visible-light irradiation for 3 h. The strategy we proposed may bring up new opportunities for an efficient photocatalytic CO2 reduction of lead-free perovskite NCs.