Metal chalcogenides (CuS or MoS2)-modified TiO2 as highly efficient bifunctional photocatalyst nanocomposites for green H2 generation and dye degradation

Abstract

Abstract Herein, we report the modification of TiO2 nanostructures with two different metal chalcogenides (CuS or MoS2). The effect of the preparation scheme (hydrothermal and coprecipitation methods) and the mass ratio of metal chalcogenides were investigated. The as-synthesized photocatalyst nanocomposites were fully characterized by various techniques. Moreover, the photo/electrochemical analysis were performed to investigate the photoelectric properties and photocatalytic mechanism. The photocatalytic performance was evaluated using two test reactions. In the case of H2 generation via water splitting, it was found that 0.5 wt% CuS-TiO2 synthesized via the coprecipitation method exhibited an initial hydrogen evolution rate (HER) of 2.95 mmol h−1 g−1. While, the optimized 3 wt% MoS2-TiO2 synthesized by the hydrothermal method, showed an HER of 1.7 mmol h−1 g−1. Moreover, the degradation efficiency of methylene blue dye was 98% under UV–Vis light irradiation within 2 h over 0.5 CT_PP and 3MT_HT. Under visible irradiation, the degradation efficiency was 100% and 96% for 3MT_PP and 0.5CT_HT in the presence of H2O2, respectively. This study has proven that metal chalcogenides can act as effective, stable, and low-cost bifunctional co-catalysts to enhance the overall photocatalytic performance.