Construction of NiO/g-C3N4 p-n heterojunctions for enhanced photocatalytic CO2 reduction

Reducing carbon dioxide (CO2) as fuel by photocatalysis is one of the effective methods in addressing the issues of fossil fuel crisis and greenhouse effect. Here, a novel p-n heterojunction made up of NiO nanosheets and g-C3N4 nanowires has been effectively fabricated on a large scale for the photocatalytic conversion of CO2 to CO and CH4. The morphologies, structures and composition of the NiO/g-C3N4 were characterized, which confirmed the being of the p-n junction between NiO nanosheets and g-C3N4 nanowires. The improved photocatalytic activities of CO2 reduction over NiO/g-C3N4 can come from the broadened light response range and the formation of the p-n junction that could deter the rapid recombination of electrons and holes. The possible photocatalytic mechanism of CO2 reduction reaction has been presented. Moreover, a novel NiO/g-C3N4 photocatalyst exhibits considerable stability for CO2 reduction. [Display omitted] •The NiO/g-C3N4 heterojunctions were assembled.•NiO/g-C3N4 enhanced activities for CO2 photoreduction.•The synergistic effect of matching band and heterojuction improved the charge separation efficiency.