Organic amine surface modified one-dimensional CdSe0.8S0.2-diethylenetriamine/two-dimensional SnNb2O6 S-scheme heterojunction with promoted visible-light-driven photocatalytic CO2 reduction

Achieving a strong redox ability and high visible-light absorption ability in a single semiconductor material is difficult. Designing a heterojunction between two semiconductor materials is a feasible method. The new step (S-scheme) heterojunction can effectively promote the separation and transfer of photogenerated electron-hole pairs and retain strong redox ability. We designed and prepared a CdSe 0.8 S 0.2 -diethylenetriamine (DETA)/SnNb 2 O 6 heterostructure material via the solvothermal method. When CdSe 0.8 S 0.2 -DETA and SnNb2O6 form an S-scheme heterojunction, 30%CdSe 0.8 S 0.2 -DETA/SnNb2O6 exhibits the highest CO production rate (17.31 μmol·g –1 ·h –1 ), which is factors of 2.8 and 4.8 higher than that of traditional solvothermal SnNb 2 O 6 (6.2 μmol·g –1 ·h –1 ) and CdSe 0.8 S 0.2 -DETA (3.6 μmol·g –1 ·h –1 ), respectively. X-ray photoelectron spectroscopy characterization data provided evidence that the transfer pathway of space charge in the CO 2 reduction process was in accordance with the S-scheme. This research provides a simple strategy through which one can optimize the band structure to promote the separation of photogenerated carriers and achieve a high efficiency of CO 2 reduction.