Efficient solar-driven CO2 reduction on aminated 2D/2D BiOBr/CdS-diethylenetriamine S-scheme heterojunction

In recent years, converting solar energy into chemical energy has been shown to be a promising method to alleviate the problem of a global energy shortage. Coupling different semiconductors to construct a step-scheme (S-scheme) heterojunction photocatalyst has become one of the most effective methods. Through the amination of CdS, a 2D/2D BiOBr/CdS-diethylenetriamine (B/CS-D) S-scheme heterojunction was constructed to achieve efficient charge carrier separation and transfer. It is worth noting that the optimal B/CS-D photocatalyst, with the BiOBr mass ratio of 40%, shows a CO production rate of 19.4 μmol h−1g−1, which is 3.68 times higher than that of CdS-D. The rate of 40%B/CS without D is 11.2 μmol h−1g−1, and the catalyst becomes severely corroded, however, by constructing an S-scheme heterojunction containing D, the stability of the photocatalyst can be improved due to the existence of amine molecules which strengthen the interface contact, and the 2D structure, which increases the area of the contact, thereby speeding up the separation and transmission of carriers. This study shows the construction of an S-scheme heterostructure photocatalyst with improved separation of photoexcited holes and electrons, and a retardation of the corrosion of CdS.