Hierarchical TiO 2 nanostructures sensitized with MoS 2 nanosheets: an efficient and reusable heterojunction photocatalyst for sunlight-assisted degradation of organic dye pollutants

The present study reports the synthesis, characterization, and natural sunlight-driven photocatalytic activity of a novel heterojunction photocatalyst comprised of hierarchical rutile titanium dioxide (r-TiO 2 ) nanostructures and 1T/2H molybdenum disulfide (MoS 2 ) nanosheets. These components were synthesized by solvothermal methods and their effective integration was achieved by using 3- aminopropyltrimethoxysilane as coupling agent. The photocatalytic activity of r-TiO 2 /MoS 2 nanohybrid was explored for the degradation of cationic dye methylene blue (MB), and anionic dye congo red (CR) under natural sunlight. The results reveal that the sunlight-driven photocatalytic activity of pristine r-TiO 2 was drastically enhanced upon sensitization with 1T/2H MoS 2 nanosheets. The nanohybrid could degrade 99% MB and 98% CR within 150 min with rate constants 25.6 × 10 −3 and 13.2 × 10 −3 min −1 respectively. The r-TiO 2 /MoS 2 nanohybrid retained more than 85% of its catalytic activity even after four cycles of reuse. The scavenger test revealed that holes and hydroxyl radicals are mainly responsible for the degradation of MB and CR. The facile synthesis, outstanding catalytic activity under natural sunlight, and excellent recyclability make r-TiO 2 /MoS 2 a promising heterojunction photocatalyst for the degradation of environmental pollutants from wastewater. The present study can provide new insights towards the development of efficient, economical and sustainable photocatalysts for harnessing renewable solar energy for environmental remediation applications.