In this study, we used sol-gel to synthesize undoped and V-ZnO nanoparticles with different vanadium concentrations (1, 3, and 5 at.%) under supercritical dry conditions of ethanol. XRD spectra showed that the obtained powders are well crystallized in the hexagonal wurtzite structure of ZnO nanoparticles. The average crystallite size, estimated by the Debye-Scherer formula, was found to be equal to 31 nm for the pure sample, and it was decreased to 27 nm for the 3at.% vanadium-doped one. SEM and TEM photographs indicated the spherical and elongated shapes of the nanoparticles. The stretching bands located at 419 cm−1 confirmed ZnO material formation. The efficacy of the produced ZnO NPs against Gram+, Gram− bacteria, and fungi was tested. Vanadium-doped ZnO, with low concentrations (10 µg/mL), exhibited a large influence on bacterial and fungi growth inhibition. For example, the inhibition zones IZ of S. aureus and E. coli bacteria reached 16 and 15 mm, respectively, for ZnO:V1%, while the IZ of these two bacteria were 14 and 12 mm for the undoped ZnO. The use of V-dopant enhanced the production of the reactive oxygen species ROS by the photogeneration of electron-hole pairs due to light absorption by ZnO in the visible region.

Sol‐gel has been used to synthesize pure and calcium doped ZnO (CZO) nanopowders under supercritical dry conditions of ethanol and characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy and Photoluminescence (PL). XRD showed that undoped and Ca‐doped ZnO samples have a hexagonal wurtzite structure with a slight distortion of ZnO lattice and no extra secondary phases, suggesting the substitution of Ca ions in the ZnO structure. The average crystallite size is increased after the addition of Ca dopant from 31 to 34 nm. PL spectroscopy showed the removal of the green emission band that existed in the pure sample; in addition to the appearance of new peaks at 408, 448, 465 and 596 nm attributed to zinc interstitials (Zni), zinc vacancy (VZn), oxygen vacancy defect (Vo) and oxygen interstitial (Oi), respectively. Antibacterial tests are performed to check the efficacity of CZO material against gram‐positive, gram‐negative bacteria and fungi. The increase in crystallites size influenced the efficacity of the CZO sample against microbes. The different mechanisms that are believed to enhance the antibacterial activities are the release of Zn2+, ROS production and electrostatic interactions. Increasing the amount of CZO powder in DMSO from 50 µg/ml to 100 µg/ml led to an increase in the antibacterial activity of the nanomaterial, and this is potentially due to the enhancement of several interaction sites. Promising results have been illustrated, which proves the potentiality of doping with this element. The growth curves through optical density (OD600 nm) measurements of the pathogenic strains in Ca‐ZnO nanoparticles using the serial fold dilution method indicated that the strains’ viability decreases with increasing nanoparticle concentrations.This article is protected by copyright. All rights reserved.

In this study, we used sol-gel to synthesize undoped and V-ZnO nanoparticles with different vanadium concentrations (1, 3 and 5 at.%) under supercritical dry condition of ethanol. XRD spectra showed that the obtained powders are well crystallised in hexagonal wurtzite structure of ZnO nanoparticles. The average crystallites size, estimated by Debye-Scherer formula, was found to be equal to 31 nm for the pure sample and it was decreased to 27 nm for the 3at.% vanadium doped one. SEM and TEM photographs indicated the spherical and elongated shape of the nanoparticles. The stretching bands located at 419 cm-1 confirmed ZnO materials formation. The efficacity of the produced ZnO NPs against G+, G- bacteria and fungi was tested. Vanadium doped ZnO, with low concentrations (10 µg/ml) exhibited a large influence on bacteria and fungi growth inhibition.