Enhanced photocatalytic CO2 reduction activity using a Bi4V2O11/single-walled carbon nanotube/g-C3N4 S-scheme heterojunction

A novel Bi4V2O11/single-walled carbon nanotube (SWNT)/g-C3N4 S-scheme heterojunction photocatalyst is prepared using an in situ solvothermal growth method. Heterostructures are constructed by coupling the defective semiconductor Bi4V2O11 with ultrathin porous g-C3N4 nanosheets. To improve the photocatalytic CO2 reduction activity, oxygen defects are used to enhance electron capture and CO2 adsorption, the S-scheme heterojunction is used to improve the separation efficiency of the photogenerated carriers and SWNTs are used to form high-speed electron transport channels. The experimental results indicate that the maximum CO formation rate of Bi4V2O11/SWNT/g-C3N4 is 18.6 μmol h−1 g−1, which is 2.7 and 2.4 times that of the ultrathin porous g-C3N4 nanosheets and Bi4V2O11 heated for 15 h, respectively, and 3.4 times that of standard g-C3N4. This work provides a vital reference point for the in situ construction of S-scheme heterojunctions with defects.