Amplifying photoreduction efficacy of Bi-Sb bimetallic nanocrystals: Manipulating carrier dynamics to boost CO2-to-CO conversion

Abstract

Inorganic Bi-based halide perovskites have attracted significant attention in the field of CO2 photoreduction due to their excellent optoelectronic conversion performance and low toxicity. However, the inherent strong localization of electron-hole pairs remains the main factors limiting charge carrier transport and CRR performance. In this work, CBSB-x NCs with different Bi/Sb ratios were synthesized assisted by ultrasound methods to manipulate carrier behavior and assess CRR performance. The photoelectrochemical properties revealed that incorporation of Sb effectively suppressed nonradiative recombination and improved transport efficiency of charge carriers. Among the bimetallic variants, CBSB-1 NCs exhibited enhanced catalytic performance in CO production, with a yield of 38.77 μmol·g−1 and a high selectivity of 96.53 %. In-situ DRIFTS and DFT calculations indicated that Sb as co-catalytic sites promote charge transfer at the Bi-Br-Sb interface, accelerate the rapid evolution of b-CO32- to HCOO- and significantly reduce the reaction energy barrier of CO.