Photocatalytic Water Disinfection of CVD Grown WS2 Monolayer Decorated with Ag Nanoparticles

Two dimensional nanostructures of transition metal dichalcogenides like WS(2 )have been drawing much attention for biological applications owing to their intrinsic chemical and optical properties with tunable band gap. We have evaluated photocatalytic properties of chemical vapor deposited (CVD) grown WS2 monolayer with a direct band gap of 1.94 eV to disinfect water from Gram-negative E.coli bacteria under fluorescence light by colony counting method. WS2 monolayer decorated with 10-15 nm silver nanoparticles is found to enhance the antibacterial activity in comparison with individual components significantly. We have achieved up to 96% of bacterial growth inhibition by increasing the areal coverage of WS2 (upto 42%) coated with Ag nanoparticles in 3 hours, under fluorescent light. Moreover, direct correlation between the water disinfection ability and geometrical surface areal coverage of the monolayer WS(2 )on SiO2/Si substrate has been established to emphasize on the need of uniform CVD growth of WS, monolayers over large scale for practical application like rapid and efficient cleaning technology.