Ternary silver tungstate-MoS₂/graphene oxide heterostructure nanocomposite for enhanced photocatalysis under visible light and antibacterial activity

Wastewater emanating out of industrial units is loaded with hazardous organic dyes. The hindrance in sunlight penetration into the water by this dye-loaded wastewater has led to disruption in an aquatic ecosystem. Along with these carcinogenic pollutants, biological pollutants such as noxious bacteria are present in wastewater posing serious health problems. Fabrication of narrow bandgap visible light active photocatalysts is crucial these days. Metal tungstates and metal sulphides are mainly being sought due to their unique tailorable optical and chemical properties. In the present study, silver tungstate-MoS₂ supported on graphene oxide was synthesized utilizing the ultrasonic-assisted hydrothermal method. The as-synthesized ternary nanocomposite was characterized by XRD, FTIR, SEM-EDS, TEM, XPS, BET, PL, and UV-vis techniques. The photocatalytic activity of prepared nanocomposites was evaluated using methyl orange degradation under visible light. The ternary nanocomposite showed improved photoefficiency, attaining 93 % methyl orange degradation in 90 min under various optimized conditions of solution pH = 5, initial dye concentration of 10 ppm, and catalyst dose of 50 mg/100 ml. The modelization and optimization for assessing the interaction effect amongst several variables were evaluated employing Response Surface Methodology (RSM). The antibacterial activity of synthesized binary and ternary hybrid nanocomposites was determined by the inactivation of gram-negative (Escherichia coli) and gram-positive (Staphylococcus aureus) bacteria. The improved photocatalytic and antimicrobial activities of ternary nanocomposite may be credited to the synergistic effect of heterojunction among three components.