Reduced graphene oxide assisted g-C3N4/rGO/NiAl-LDHs type II heterostructure with high performance photocatalytic CO2 reduction

Photocatalytic CO2 reduction has been considered as a potential way to solve the energy problem and the greenhouse effect. In this work, layered g-C3N4/rGO/NiAl-LDHs heterojunctions were prepared by using a hydrothermal method, the optimized composite exhibited enhanced photocatalytic CO2 reduction to CO (2.6 μmol h−1g−1) and CH4 (20 μmol h−1g−1) activity, which was 3.7 and 14.2 times higher than that of pure g-C3N4, respectively. According to the experimental and density functional theory calculation (DFT) results, it is believed that with the large contact interface and excellent electron mobility rGO could act as an electron transfer bridge to facilitate the rapid charge migration and separation between g-C3N4 and NiAl-LDHs. Thus, driven by the internal electric field, interfacial band edge bending, as well as the type II heterostructure, the activity of g-C3N4/rGO/NiAl-LDHs could be greatly enhanced. This work provides a possible way to rational design and fabrication of rGO-assisted composite systems with type II, Schottky, S-scheme, P-N and other heterojunctions.