Spherical montmorillonite-supported molybdenum disulfide nanosheets as a self-sedimentary catalyst for organic pollutants removal

Water containing organic and carcinogenic pollutants has become a serious environmental problem, threatening the life of the aquatic ecosystem and human beings. Molybdenum disulfide (MoS2), especially monolayered MoS2 sheets, has been proven as an effective catalyst for degradation of organic contaminants due to its more exposed edges and active sites for electron transfer. However, monolayered MoS2 nanosheets easily aggregate due to their high surface energy and strong pi-pi electron interaction, heavily affecting the catalytic performances. In addition, monolayered MoS2 nanosheets with small tiny size are difficult to recover from the mixture, restricting the capacity of recyclability and further mass application. Herein, we solved these issues via supporting the small tiny MoS2 nanosheets on spherical montmorillonite (SMt). The SMt can not only provide large pore volume and specific surface area for supporting abundant MoS2 but also reduce the fouling and enhance the transport during the mass production process. The prepared microspheres exhibited a high catalytic activity towards organic pollutants including methylene blue (MB) and 4-nitrophenol (4-NP) in the presence of NaBH4 due to the strong adsorption capacity of SMt and the large catalytic surface area for electron transfer. Furthermore, the micro-sized granular catalyst can be facile recovered and reused without any devices involved due to the excellent self-sedimentary capacity and large size. Moreover, the catalytic performance and the morphology were almost unaltered after recycling 20 times. Our straightforward strategy to solve the issues through porous micro-sized self-sedimentary SMt supporting tiny monolayered MoS2 nanosheet with high catalytic activity facilitates the practical application of these kinds of catalyst towards the reduction of organic and carcinogenic pollutants.