Cu2O/reduced graphene oxide composites for the photocatalytic conversion of CO2.

A facile one-step microwave-assisted chemical method has been successfully used for the synthesis of Cu2O/reduced graphene oxide (RGO) composites. Photocatalytic CO2 reduction was then investigated on the junction under ambient conditions. The RGO coating dramatically increases Cu2O activity for CO2 photoreduction to result in a nearly six times higher activity than the optimized Cu2O and 50 times higher activity than the Cu2O/RuOx junction in the 20(th) hour. Furthermore, an apparent initial quantum yield of approximately 0.34 % at 400 nm has been achieved by the Cu2O/RGO junction for CO2 photoreduction. The photocurrent of the junction is nearly double that of the blank Cu2O photocathode. The improved activity together with the enhanced stability of Cu2O is attributed to the efficient charge separation and transfer to RGO as well as the protection function of RGO, which was proved by XRD, SEM, TEM, X-ray photoelectron spectroscopy, photo-electrochemical, photoluminescence, and impedance characterizations. This study further presents useful information for other photocatalyst modification for efficient CO2 reduction without the need for a noble-metal co-catalyst.