Self-assembled flower-like (BiO)2CO3–CdS–CuS stable heterojunction degrades toluene under visible light response

Abstract The toluene as a representative VOCs is not only difficult to degrade, but also very harmful. In this manuscript, we use photocatalytic materials to degrade toluene. At first, the sheet-like structure decorated (BiO)2CO3 flowers were fabricated. The tight decoration of sheet-like structure over (BiO)2CO3 flowers provided greater specific surface area to contact with the toluene. Finally, the (BiO)2CO3 and CdS–CuS were fabricated to form a ternary heterojunction by one-step hydrothermal method. The activity enhancement should be ascribed to that the ternary heterojunction could produce more active material •OH for toluene degradation. The 3p-orbital in the sulfur atom in CuS can be used as an electron acceptor to effectively improve the stability of sulfur vacancies on the surface of CdS. In addition, the presence of CuS could solve the problem of deactivation caused by photo-etching of CdS under illumination conditions. The valence change of the S element in CuS-CdS-BOC is only 1.1%, but up to 7.5% in CdS-BOC before and after the reaction. The highest degradation effect was exhibited, the degradation of toluene at 3000 ppm could reach 67%. In addition, The band gap of the composite material was reduced from 3.2eV to 2.25eV. A new alternative catalytic material was provided for the degradation of toluene. A reliable strategy was provide for enhancing the stability of S in CdS by this work.