Unveiling photochemical CO2 reduction processes on PbBiO2I/GO surfaces: Insights from in-situ Raman spectroscopy

Bismuth-based materials are increasingly valued for their dual capability in catalyzing the photochemical CO2 reduction reaction (CO2RR) and enhancing the selectivity towards multi-carbon (C2+) products. This study introduces a novel PbBiO2I/graphene oxide (PbBiO2I/GO) composite, synthesized to leverage the unique properties of both components for improving catalytic performance. The physical and chemical properties of these composites were characterized to delineate their functionality and interaction mechanisms. The heterojunction structure in the composites significantly facilitated the CO2RR, with a noted CH4 conversion rate of 0.8376 mu molg(-1)h(-)1. This rate is significantly higher similar to 1.78 times that of standalone PbBiO2I under similar conditions. Advanced X-ray photoelectron spectroscopy (XPS) analysis indicated that the incorporation of graphene oxide enhances the electronic environment around Pb2+ and Bi3+ ions, reducing their charge states and increasing oxygen vacancies. This modification likely contributes to the observed catalytic enhancement. Furthermore, in-situ Raman spectroscopy provided insights into the dynamic formation of key intermediates during the CO2RR. Under targeted light irradiation, distinct intermediates such as *COO, *CO, H*CO/H*COH, OC*C*O, O*CCHO, and C-H were detected, facilitating a deeper understanding of the mechanistic pathways involved in C1 and C2 product formation. This comprehensive analysis not only elucidates the enhanced catalytic pathways facilitated by the composite structure but also sets a foundation for future optimizations in bismuth-based photocatalytic systems.