Synergistic photocatalytic and antibacterial efficacies of Ag/rGO and Ag/Ag2O/rGO nanocomposites: The impact of oxide formation and ternary heterojunction

Abstract

This study explores the efficient solvothermal integration of Ag/rGO and Ag/Ag2O/rGO nanocomposites using various solvents and employs thorough characterization procedures. The primary focus is on understanding the nuanced effects resulting from the combination of Ag nanoparticles with rGO nanosheets, particularly in the context of Ag2O formation. For a quantitative assessment of their photocatalytic and antibacterial properties, graphene oxide and silver nitrate (AgNO3) were introduced to create Ag/rGO and Ag/Ag2O/rGO nanocomposites. The results demonstrate a significant enhancement in photocatalytic performance for the Ag/Ag2O/rGO nanocomposite, achieving a rapid degradation of 99.99 % of methylene blue dye within 30 minutes under simulated solar light irradiation. This heightened efficiency is attributed to improved separation and transfer efficiency, as well as the substantial generation of photoinduced carriers due to the incorporation of visibly active Ag2O nanoparticles. Moreover, the Ag/Ag2O/rGO nanocomposite exhibits an enhanced antibacterial activity, reflected in Minimum Inhibitory Concentration (MIC) values of 50 μg/ml for Bacillus cereus and 300 μg/ml for Escherichia coli. The nanocomposite's higher antimicrobial activity against Gram-positive bacteria, particularly Bacillus cereus, is underscored, revealing its potential as an effective antibacterial agent. The formation of a ternary heterojunction in the Ag/Ag2O/rGO nanocomposite results in a notable increase in the production of free radicals, enhancing charge carrier migration and separation efficiency. This quantitative evidence emphasizes the versatile nature of the nanocomposite, highlighting its potential across diverse fields through augmented antibacterial and photocatalytic properties.