Preparation of black hollow TiO2 nanotube-coated PDA@Ag2S heterostructures for efficient photocatalytic reduction of Cr(VI)

At present, hexavalent chromium (Cr(VI)) has a serious impact on the water environment and human beings since it can be easily absorbed by the human body, lethal to aquatic organisms and carcinogenic to humans. Based on this, a black hollow TiO 2 nanotube supported polydopamine (PDA)@Ag 2 S composite photocatalytic material was prepared, which can be used for the efficient photocatalytic reduction of Cr(VI) in wastewater. Both black hollow TiO 2 and Ag 2 S have the shortcoming of undergoing ready recombination of photogenerated carriers. The introduction of PDA can not only improve the photogeneration of composite photocatalytic materials, but also broaden the absorption range in the visible-light region. A detailed mechanism for the TiO 2-x @PDA@Ag 2 S photocatalytic system has been proposed at the same time. This work provides a new methodology for the design and synthesis of sandwich organic-inorganic hybrid photocatalytic materials.