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

Abstract

Two dimensional nanostructures of transition metal dichalcogenides like WS2 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 WS2 on SiO2/Si substrate has been established to emphasize on the need of uniform CVD growth of WS2 monolayers over large scale for practical application like rapid and efficient cleaning technology.

WS2 Monolayer for Piezo–Phototronic Dye Degradation and Bacterial Disinfection

“…During this process, these free charge carriers react with adsorbed O 2 and H 2 O (solvent), and, hence, ROS, i.e., • OH and • O 2 – , are produced much more efficiently, as shown in eqs and . This is how WS 2 smartly contributes to the disinfection of bacteria by producing ROS, which prevents DNA replication. , Furthermore, ROS is also reported to cause lipid membrane peroxidation and damage DNA/proteins. By these methods, ROS kills the bacteria, and such an enhancement of the antibacterial activity of WS 2 with the aid of external stimulation such as vibration and light paves the way to improving the protection against microorganisms.…”

Nanomaterial-Based Antimicrobial Coating for Biomedical Implants: New Age Solution for Biofilm-Associated Infections

“…This prompted researchers to investigate the area in the quest of more efficient, enhanced, and cutting-edge methods to boost the antibacterial and antibiofilm activity for such surfacemodified medical devices and implants. An overwhelming number of studies have been performed on silver-based nanocomposite biomaterial in these past years due to their known ability to act as an antimicrobial 163 and antibiofilm agent for pathogens involved in nosocomial infections. In 2009, Stobie and co-workers investigated the role of silver-doped perfluoropolyether-urethane coatings as a surface modification for biofilm inhibition.…”

Solar‐Driven Photocatalytic Disinfection Over 2D Semiconductors: The Generation and Effects of Reactive Oxygen Species

“…[ 81 ] The TMD nanosheets show distinctive features in terms of optical and electric properties, which allow this group to be fit for photocatalysis. [ 82 ] For environmental application, the TMD nanosheets with sharp edges and oxidation capacities in the dark could act as antibacterial reagents regardless of irradiation. [ 81,83,84 ] The material group also shows photothermal and photocatalytic effects under light exposure.…”

“…Reproduced with permission. [ 82 ] Copyright 2018, Wiley. c) Schematic illustration of the fabricated MoS 2 /TiO 2 nanoarrays on a Ti mesh via anodic oxidation (left); SEM images of the Ti substrates (middle) and MoS 2 /TiO 2 arrays (left).…”

“…A hybrid of CVD‐grown WS 2 nanolayers and silver particles on Si/SiO substrate could achieve up to 96% disinfection toward 5 log E. coli under 12 h continuous irradiation (Figure 17b). [ 82 ] Following the success by Liu et al who seeded MoS 2 vertical arrays on a glassy‐carbon substrate, [ 171 ] Ghoshal et al grew vertical ReS 2 sheets on a SiO 2 /Si wafer via the CVD method for solar‐assisted disinfection. [ 278 ] The dense ReS 2 nanosheets that exhibited out‐of‐plane growth mode possessed an abundant exposure of active edges compared with the flat grown sheets.…”