Microwave assisted CdO–ZnO–MgO nanocomposite and its photocatalytic and antibacterial studies

CdO–ZnO–MgO nanocomposite was synthesized by the microwave-assisted method and characterized by X-ray diffraction (XRD), FTIR, FESEM with energy dispersive X-ray spectrometry and TEM. XRD revealed the existence of the CdO (cubic)–ZnO (hexagonal)–MgO (cubic) structure with an average crystallite size of CdO (33 nm), ZnO (35 nm), MgO (30 nm) and also the dislocation density is evaluated. FTIR confirmed the presence of Cd–O, Zn–O and Mg–O by characteristic vibrational peaks at 863, 566 and 693 cm− 1. The surface morphological (FESEM and TEM) images appear the agglomerated rod-like structure. From the UV–Vis spectra, the bandgap is estimated as 2.67 eV. The prepared nanocomposite acts as an excellent photocatalyst for the removal of both dyes (Methylene blue and Congo red) under solar light irradiation. The antibacterial activity was carried out at different concentrations (25, 50, 75 and 100 µg/ml) in vitro against Escherichia coli, Pseudomonas aeruginosa, Vibrio cholera, Klebsiella pneumoniae, Proteus vulgaris, Salmonella typhi (G −ve); Bacillus subtilis (G +ve) bacteria. The zone of inhibition of 25 mm has a high antibacterial activity towards the gram-negative bacterium (P. vulgaris).