Construction and enhanced photocatalytic activities of a hydrogenated TiO2 nanobelt coated with CDs/MoS2 nanosheets

A few-layered CDs (carbon dots)/MoS2 nanosheet-coated hydrogenated TiO2 (H-TiO2) nanobelt heterostructures—referred to as CDs/MoS2@H-TiO2—with a flexible three-dimensional (3D) hierarchical configuration were prepared via a facial hydrothermal reaction. Note that the visible photocatalytic activity of H-TiO2 was improved compared with that of pristine rutile TiO2, which can be mainly attributed to the optical absorption and charge carrier trapping of oxygen vacancies and Ti ions in TiO2 nanobelts created by the hydrogenation. The CDs/MoS2@H-TiO2 ternary photocatalysts exhibit excellent UV and visible photocatalytic property. Via optimizing the proportion of each component, the CDs/ MoS2@H-TiO2 composite showed the highest photocatalytic degradation activity when the content of the CDs/MoS2 co-catalyst was 5.0 wt% and the content of CDs in this cocatalyst was 25%. Further study revealed that the considerable photodegradation rate under UV irradiation and a large promotion of the photocatalytic activity in both the visible and near-infrared (NIR) region originated from the synergistic effect of oxygen vacancies, interfacial modification, and the vectorial charge-transfer channel design. Our study provides a desired strategy to understand and realize a rationally designed electronic transition between a semiconductor and cocatalysts, which is of great importance for the enhancement of charge separation and obtaining improved photocatalytic performance.