Construction of AgBr/BiOBr S-scheme heterojunction using ion exchange strategy for high-efficiency reduction of CO2 to CO under visible light

CO2 reduction via photocatalytic is regarded as the excellent strategy to resolve the severe environmental crisis and energy crisis caused by the accelerated utilization of fossil energy like natural gas, oil, and coal. The Ag ion and the Br ion in BiOBr are creatively used in the ion exchange strategy to form AgBr on the surface of BiOBr, and an S-scheme BiOBr/AgBr heterojunction with close interface contact is constructed. The visible light utilization rate and CO2 conversion rate of the obtained heterojunction are both remarkably improved. The reduction rate of CO2 over the catalyst was tested under visible light using pure water as the liquid environment. As obtained results displayed that the transformation efficiency of BA-1 to CO from CO2 in the visible light was 12.43 mu mol g -1h-1 , which is about 3 times that the pristine BiOBr. The intermediates during the reaction were studied using in situ DRIFTS. The process by which CO2 was degraded was speculated based on in situ DRIFTS spectra. In addition, TPR, EIS, and PL measurements indicate that BA-1 has a high solar utilization rate and strong photo -generated carrier transfer and separation capability. This work showed a novel direction for preparation of efficient photocatalyst for CO2 reduction.