Carbon dots modified dendritic TiO2-CdS heterojunction for enhanced photodegradation of rhodamine and hydrogen evolution

Heterojunction modified by nanosized interfacial contact stands out in promoting the transport of photogenerated charge carriers. In this work, a dendritic ternary photocatalyst of CdS-TiO2 heterojunction modified by carbon dots (CDs) was prepared by simple hydrothermal method and impregnation method, and the catalysts were characterized by XRD, SEM, TEM, XPS, Uv-vis and ESI. It was found the ternary photocatalyst endows excellent performance in degradation and photolysis of water due to the features of high surface, rich surface function groups, and high conductivity of CDs. Compared with the CdS-TiO2 photocatalyst, the RhB degradation rate of CDs-CdS-TiO2 increased from 69.0 % to 84.5 % in 50 min, and the rate of hydrogen production increased by 3.0 times, reaching 790.6 μmol g−1 h−1. Dendritic CdS-TiO2 heterojunctions and decorated with CDs lead to the increase of the absorption range in the visible region. Combined with theoretical calculations, the introduce of CDs can improve the photo-generated electron-hole separation and carrier transfer rate in CdS-TiO2 heterojunction when electrons are transferred from TiO2 to CdS.