Synthesis of MoS₂/TiO₂ Nanophotocatalyst and Its Enhanced Visible Light Driven Photocatalytic Performance.

Molybdenum disulfide (MoS₂), as a typical layered transition metal sulfide, has been widely used in photocatalysis. Here, we report layered MoS₂ nanosheet-coated TiO₂ heterostructures that were prepared using a simple photo-assisted deposition method. The as-prepared samples were investigated in detail by using X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy. Results demonstrated that the MoS₂ nanosheets uniformly covered the outer surface of TiO₂. The visible light-sensitive photocatalytic activity was evaluated by the removal of methylene blue (MB) and 2-chlorophenol (2-CP) in aqueous solution. Thus, the MoS₂/TiO₂ heterostructures exhibited improved photocatalytic degradation activity under visible light compared with the pure TiO₂. Under visible light irradiation for 90 min, the degradation efficiencies of MB and 2-CP over the MoS₂/TiO₂ sample (sunlight irradiation time: 30 min) are as high as 93.6% and 70.6%, respectively. Furthermore, the corresponding mechanism of enhanced photocatalytic activity is proposed on the basis of the comprehensively investigated results from the radical trapping experiments, photoluminescence spectroscopy, and electron spin resonance analysis. The hole oxidation, hydroxyl radicals, and superoxide anion radicals act as the active species simultaneously in the photodegradation of the dye molecules. However, of these species, hole oxidation played the most important roles in the photocatalytic reaction.