Reduced graphene oxide–CuO nanocomposites for photocatalytic conversion of CO2 into methanol under visible light irradiation

Abstract

Reduced graphene oxide (rGO)–copper oxide nanocomposites are prepared by covalent grafting of CuO nanorods on the rGO skeleton. Chemical and structural features of rGO–CuO nanocomposites are probed by FTIR, XPS, XRD and HRTEM analyses. Photocatalytic potential of rGO–CuO nanocomposites is explored for reduction of CO2 into the methanol under the visible light irradiation. The breadth of CuO nanorods and the oxidation state of Cu in the rGO–CuO/Cu2O nanocomposites are systematically varied to investigate their photocatalytic activities. The pristine CuO nanorods exhibited very low photocatalytic activity owing to fast recombination of charge carriers and yielded 175μmolg−1 methanol, whereas rGO–Cu2O and rGO–CuO exhibited significantly improved photocatalytic activities and yielded five (862μmolg−1) and seven (1228μmolg−1) folds methanol, respectively. The superior photocatalytic activity of CuO in the rGO–CuO nanocomposites was attributed to slow recombination of charge carriers and efficient transfer of photo-generated electrons through the rGO skeleton. This study further excludes the use of scavenging donor.