Insights on photocatalytic dye inactivation and antimicrobial activity of pH-dependent facile synthesised copper oxide nanoparticles

Photocatalytic efficacy of copper oxide nanoparticles (CuO Nps) synthesised by a simple wet chemical route at different pH values ranging from 4 to 10 was investigated. The synthesised nanoparticles were characterised by analytical tools such as X-ray diffraction (XRD), diffuse reflectance spectroscopy, photoluminescence, scanning electron microscope and Raman spectroscopy. The XRD pattern endorses the formation of monoclinic CuO with an average particle size of 26 nm at higher pH (pH 8), whereas at lower pH levels (pH 4 & 6) copper oxide complexes with monoclinic structure were observed. The diffuse reflectance spectrum of the CuO Nps showed band gap energy of ~ 1.4 eV. The SEM images displayed diverse morphologies while altering the pH during the synthesis process of CuO Nps. The degradation efficiency of CuO Nps towards rhodamine B was recorded as 88% after 6 h and could be reused. The extent of mineralisation of the dyes was evaluated by chemical oxygen demand. Owing to the application of remediation of contaminated water, the samples were also treated with different gram-positive and gram-negative bacteria and showed efficient against the microbes harmful to human lungs.