Visible light induced selective photocatalytic reduction of CO2 to CH4 on In2O3-rGO nanocomposites

Abstract

Maintaining the atmospheric CO2 by its utilization in the production of valuable solar fuel like methane is one of the major challenges for humankind. Photocatalytic reduction of CO2 is a vital approach for its consumption by conversion into a valuable chemical product. Here, we prepared In2O3-rGO nanocomposites with varying reduced graphene oxide (rGO) content for the investigation of photocatalytic reduction of CO2. The product yield obtained by photocatalytic reduction of CO2 by visible light source was quantified by exploring the gas chromatography measurements. The catalytic activity of In2O3-rGO nanocomposites towards the photocatalytic reduction process of CO2 to CH4 gets enhanced as compared to In2O3 nanostructures due to the enhancement of lifetime of separation of photogenerated electron-hole pairs, which assist in improvement of charge transfer from In2O3 to rGO under visible light source. The In2O32wt%rGO nanocomposite exhibits a maximum methane yield of 953.72 μmol.g−1. The highest catalytic performance of In2O3-2wt%rGO nanocomposite may be attributed to improvement in its optical properties such as optical band gap and oxygen vacancies (Vo) defects by the addition of rGO in it. A mechanism based on the oxygen vacancies mediated charge transfer process is invoked to explain the observed enhancement in the photocatalytic reduction of CO2.