Department of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, 212003, P. R. China.
Key Laboratory of Industrial Ecology and Environmental Engineering and State Key Laboratory of Fine Chemical, School of Environmental Sciences and Technology, Dalian University of Technology, Dalian, 116024, P. R. China.
J Nanosci Nanotechnol. 2019 Jun 1;19(6):3519-3527. doi: 10.1166/jnn.2019.16122.
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.
二硫化钼（MoS₂）作为一种典型的层状过渡金属硫化物，已被广泛应用于光催化领域。在此，我们报告了一种采用简单的光辅助沉积法制备的层状 MoS₂纳米片修饰的 TiO₂异质结。通过 X 射线衍射、拉曼光谱、扫描电子显微镜、透射电子显微镜和 X 射线光电子能谱对所制备的样品进行了详细的研究。结果表明，MoS₂纳米片均匀地覆盖在 TiO₂的外表面上。通过在水溶液中去除亚甲基蓝（MB）和 2-氯苯酚（2-CP）来评估可见光敏感的光催化活性。因此，与纯 TiO₂相比，MoS₂/TiO₂异质结在可见光下表现出了提高的光催化降解活性。在可见光照射 90 分钟后，MoS₂/TiO₂样品（阳光照射时间：30 分钟）对 MB 和 2-CP 的降解效率分别高达 93.6%和 70.6%。此外，基于自由基捕获实验、光致发光光谱和电子顺磁共振分析的综合研究结果，提出了增强光催化活性的相应机制。在染料分子的光降解过程中，空穴氧化、羟基自由基和超氧阴离子自由基同时作为活性物质起作用。然而，在这些物质中，空穴氧化在光催化反应中起着最重要的作用。
