Synergistic bifunctionality of ZnO nanowalls: Antibacterial activity and photocatalysis through integrated in silico and in vitro approaches

Abstract

This research investigation delves into the versatile attributes of ZnO nanowalls, specifically probing into their dual functionality encompassing antibacterial and photocatalytic properties. The synthesis of ZnO was achieved by employing a microwave-mediated co-precipitation technique. The resulting sample underwent thorough characterization through diverse analytical methodologies. X-ray diffraction analysis disclosed the prevalence of the hexagonal wurtzite phase, as confirmed by JCPDS card No. 36–1451, with an average crystallite size determined as 23.48 nm. Tauc plot extrapolation method was applied to the UV absorption spectrum to ascertain the bandgap energy. The ZnO nanostructure morphology, featuring multi-directional nano-walls, was unveiled through scanning electron microscopy (SEM). The BET nitrogen adsorption technique quantified the surface area of the ZnO sample as 6.69 m2/g. In antibacterial evaluation, the in vitro (disk diffusion) method showcased the remarkable efficacy of ZnO against both gram-positive Staphylococcus sp. and gram-negative E. coli bacteria. Complementing these experimental findings, in silico molecular docking studies exposed both nano ZnO ligands with standard and corrected lattice parameter values exhibiting favorable binding energy. Moreover, the synthesized ZnO nanoparticles exhibited remarkable photocatalytic activity, particularly demonstrated in the decolorisation of Azure A and Azure B dyes, following the first-order Langmuir–Hinshelwood kinetic model. The collective findings underscored a synergistic effect within the fabricated ZnO nanoparticles, showcasing their dual prowess in both antibacterial and photocatalytic activities. The observed phenomenon can be chiefly ascribed to the presence of lattice strain and dislocation density. This intriguing dual functionality positions them as promising candidates for potential applications in wastewater treatment.