High-Efficiency Photocatalytic Degradation of Tannic Acid Using TiO2 Heterojunction Catalysts

Photocatalysts have been extensively used for hydrogen evolution or organic degradation. In this work, two different heterojunction types of composite photocatalysts, 1T-MoS2@TiO2 with Schottky heterojunction and 2H-MoS2@TiO2 with type-II heterojunction, are synthesized via hydrothermal synthesis. These two composite materials exhibit excellent photocatalytic activity toward the degradation of tannic acid, which is a typical organic in nuclear wastewater. At an optimal loading of 16% 1T-MoS2, the 1T-MoS2@TiO2 shows the highest degradation capacity of 98%, which is 3.2 times higher than that of pure TiO2. The degradation rate of 16% 1T-MoS2@TiO2 is much higher than that of 13% 2H-MoS2@TiO2. The enhanced photocatalytic activity might be attributed to the improved charge transfer according to the mechanism investigation, supported by the X-ray photoelectron spectroscopy (XPS) and electrochemical impedance spectroscopy (EIS) analyses. This work provides new opportunities for constructing highly efficient catalysts for nuclear waste disposal.