Effect of reaction time on plasma-liquid electrochemical synthesis of chromium oxide nanoparticles

This study investigates the synthesis of chromium oxide (Cr2O3) nanoparticles using a plasma-liquid electrochemical technique with chromium (III) nitrate nonahydrate as the precursor and fructose as the stabilizer. This synthesis technique enables the production of high-purity nanoparticles with precise control of size and morphology, in an environmentally friendly and efficient manner. The aim of this study is to examine the influence of reaction time (10–30 min) on the morphology, structural, optical characteristics, and antibacterial performance of nanoparticles. The XRD analysis reveals that by increasing the reaction time, a corresponding increase in the crystallite size of the Cr2O3 nanoparticles is attained. UV–Vis spectroscopy indicates that prolonged processing time results in a reduction of the band gap (3.45, 2.47, and 2.35 eV). SEM images show that particle size increases (41–59 nm) with longer treatment durations, likely caused by increased particle interaction and growth rates. The antibacterial tests show that synthesized chromium oxide nanoparticles exhibit significant inhibitory effects on Gram-negative bacteria (E. coli), whereas moderate activity was observed against Gram-positive bacteria (S. aureus). These findings indicate that chromium oxide nanoparticles can be effectively synthesized by the plasma-liquid electrochemical technique, and the characteristics of nanoparticles and their applicability as an antibacterial material are optimum at a reaction time of 20 min. The change in reaction time has a significant impact on the total cost when any synthesis is carried out on a large industrial scale, and it is necessary to optimize the time at which better characteristics at a low production cost can be attained.