Dual p-n Z-scheme heterostructure boosted superior photoreduction CO2 to CO, CH4 and C2H4 in In2S3/MnO2/BiOCl photocatalyst

Abstract

The creation of a Z-scheme heterojunction is a sophisticated strategy to enhance photocatalytic efficiency. In our study, we synthesized an In2S3/MnO2/BiOCl dual Z-scheme heterostructure by growing BiOCl nanoplates on the sheets of In2S3 nanoflowers, situated on the surface of MnO2 nanowires. This synthesis involved a combination of hydrothermal and solution combustion methods. Experiments and density functional theory (DFT) calculations demonstrated that the In2S3/MnO2/BiOCl composite exhibited notable photo reduction performance and photocatalytic stability. This was attributed to the pivotal roles of BiOCl and MnO2 in the composite, acting as auxiliaries to enhance the electronic structure and facilitate the adsorption/activation capacity of CO2 and H2O. The yield rates of CO, CH4, and C2H4 over In2S3/MnO2/BiOCl as the catalyst were 3.94, 5.5, and 3.64 times higher than those of pure In2S3, respectively. Photoelectrochemical analysis revealed that the dual Z-scheme heterostructure, with its oxygen vacancies and large surface area, enhanced CO2 absorption and active sites on the nanoflower/nanowire intersurfaces. Consequently, the dual Z-scheme charge transfer pathway provided efficient channels for boosting electron transfer and charge separation, resulting in high C2H4, CH4, and CO yields of formed and exihibits an promising photoreduction rate of CO2 to CO (51.2 µmol/g.h), CH4 (42.4 µmol/g.h) and C2H4 (63.2 µmol/g.h), respectively. DFT, in situ Diffuse reflectance infrared fourier transform spectroscopy, and temperature-programmed desorption tests were employed to verify the intermediates pathway. The study proposed a potential photocatalytic mechanism based on these findings.