A B S T R A C TThe paradigm modifications in the metallic crystals from bulky to micro-size to nano-scale have resulted in excellent and amazing properties; which have been the remarkable interests in a wider range of applications. Particularly, Ag NPs have much attention owing to their distinctive optical, chemical, electrical and catalytic properties that can be tuned with surface nature, size, shapes, etc. and hence these crystals have been used in various fields such as catalysis, sensor, electronic components, antimicrobial agents in the health industry etc. Among them, Ag NPs based disinfectants have paid attention due to the practical applications in our daily life.

Herein, a protocol strategy has been designed for the preparation of ternary silver nanoparticles-supported polyaniline multiwalled carbon nanotube (Ag NPs–PANI/MWCNT) nanocomposites with a chemical interaction for catalytic and antibacterial activity. The morphological study confirmed that Ag NPs were immobilized on the surface of PANI, and afterward, Ag NPs–PANI were mixed with the MWCNTs. The X-ray diffraction technique revealed the face-centered cubic structure of Ag NPs, and the X-ray photoelectron spectroscopy study revealed the chemical constituent and signature of π–π* and C–N interactions in the nanocomposites. The ternary Ag NPs–PANI/MWCNTs nanocomposites have the apparent rate of reaction (K app) as 5.4 × 10–3 s–1, higher than binary nanocomposites for catalytic reduction of 4-nitrophenol to 4-aminophenol at room temperature. Antibacterial activity of Ag NPs–PANI/MWCNT nanocomposites is higher against pathogenic bacteria. Thereafter, because of multifold applications of ternary nanocomposites, they have a broad scope in the field of environmental and healthcare sectors.

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Supported silver nanoparticles (Ag NPs) were prepared by chemical reduction method with a sol-gel method. The structure, morphology, and interconnectivity of Ag/TiO nanocomposites (NCs) were analyzed using different instrumental techniques. Transmission electron microscopy reveals the Ag NPs have uniformly distributed and anchored on the surface of TiO . The reduction in electron-hole recombination was measured by Photoluminescence measurements lead, to an increased photocatalytic inactivation of bacteria. Increase in the amount of Ag NPs on TiO resulted in a slight decrease in optical band gap energy of TiO . The effect of Ag NPs content on the photocatalytic properties of TiO for inhibition of bacteria in visible light irradiation was studied. Furthermore, the antibacterial activity of Ag/TiO NCs in the presence of UVA light was studied against gram-positive Staphylococcus aureus and gram-negative Escherichia coli bacterial strain by plate count method. Lower values of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of the catalysts were observed and used to determine the tolerance factor which is shown bactericidal nature of the NCs. Subsequently, time-killing assay of Ag/TiO NCs was shown dynamics of antimicrobial activity. These multifold antibacterial studies exhibited potent antibacterial nature of the NCs and employed in the wider range of biomedical fields.