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In the present work, pristine anatase titanium oxide (TiO2), vanadium oxide (V2O5), and yttrium oxide (Y2O3) nanopowders (NPs), and tri-phase TiO2–Y2O3–V2O5 nanocomposite (NC) were prepared via a simple co-precipitation method. The grown products were characterized by employing a range of techniques, including X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), ultraviolet–visible spectroscopy (UV–vis), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX) analysis. The XRD diffraction pattern confirmed the formation of NC having TiO2 tetragonal, Y2O3 cubic, and V2O5 orthorhombic phases. FTIR spectra evident the presence of metal–oxygen bond in NPs and NC. The energy bandgap (2.55 eV) of NC is found in the range of visible region specified its use as an efficient photocatalyst under sunlight illumination. EDX analysis confirmed the existence of Ti, Y, and V in the nanocomposite. The antibacterial studies against Staphylococcus aureus, Klebsiella pneumonia, and Proteus vulgaris bacteria by varying concentrations (10, 20, 30, and 40 mg ml−1) showed that the NC has higher antibacterial activity than individual oxides. The photocatalytic activity exhibited that NC has the highest degradation efficiency 99.29%, 90.69%, and 99.83% against methylene blue (MB), safranin-O (SO), and methyl orange (MO) dyes as compared to pristine TiO2, V2O5, and Y2O3 NPs under 80 min direct sunlight irradiation. Furthermore, the grown NC is a good candidate for treating organic pollutants and bacteria inactivation.

In this work, we focus on the synthesis of Cu0.95Zn0.05O and Cu0.9Zn0.05M0.05O (M = Cr, Co, Cd) nanocrystals by employing low-cost sol–gel method. The effect of single doping and co-doping on physical, antibacterial, and photocatalytic properties of CuO has been successfully investigated using characterization tools comprising XRD, SEM, FTIR, UV–Vis, and I–V measurements. X-ray diffraction pattern exhibited that the grown product of CuO has no traces of impurities, indicated the successful incorporation of dopants without changing monoclinic structure. The X-ray peak profile analysis was adopted to calculate the average crystallite size (D) by considering the contributions of lattice strain on peak broadening. The calculated direct energy bandgap indicated redshift (1.26 eV to 1.81) eV by co-doping. The I–V study revealed the enhancement in electrical properties by co-doping. The effects of co-doping on photocatalytic properties of CuO were studied by degradation of methylene blue (MB) and methyl orange (MO) dyes under direct sunlight. The Zn/Cd-doped nanocrystal has a higher degradation efficiency 98.4% against MB and 96.1% against MO dye in 50 min. The enhanced photodegradation is due to the generation of reactive species confirmed by scavenger's experiments. The recyclability test showed the reusability of grown catalyst up to the 4th cycle. The antibacterial property was studied against Staphylococcus aureus and Klebsiella pneumoniae bacterial strains, which showed the highest zone of inhibition 31 mm, and 32 mm for co-doped samples. Furthermore, the present study paves the path to modify the properties of CuO for optoelectronic devices, environmental, and biomedical applications.

Novel tri-phase CuO-MgO-ZnO nanocomposite was prepared using the co-precipitation technique and investigated its physical properties using characterization techniques including XRD, FTIR, Raman, IV, UV-vis, PL, and SEM. The application of grown CuO-MgO-ZnO nanocomposite for the degradation of various dyes under sunlight and antibacterial activity against different bacteria were studied. The XRD confirmed the existence of diffraction peaks related to CuO (monoclinic), MgO (cubic), and ZnO (hexagonal) with CuO phase 40%, MgO 24%, and ZnO 36%. The optical energy gap of nanocomposite was 2.9 eV, which made it an efficient catalyst under sunlight. Raman and FTIR spectra have further confirmed the formation of the nanocomposite. SEM images revealed agglomerated rod-shaped morphology. EDX results showed the atomic percentage of a constituent element in this order Cu>Zn>Mg. PL results demonstrate the presence of intrinsic defects. The photocatalytic activity against methylene blue (MB), methyl orange (MO), rhodamine-B (RhB), cresol red (CR), and P-nitroaniline (P-Nitro) dyes has shown the excellent degradation efficiencies 88.5%, 93.5%, 75.9%, 98.8%, and 98.6% at 5 ppm dye concentration and 82.6%, 83.6%, 64.3%, 93.1%, and 94.3% at 10 ppm dye concentration in 100 min, respectively, under sunlight illumination. The higher degradation is due to the generation of superoxide and hydroxyl radicals. The recyclability test showed the reusability of catalyst up to the 5th cycle. The antibacterial activity against Escherichia coli, Klebsiella pneumoniae, Proteus Vulgaris, Staphylococcus aureus, and Pseudomonas aeruginosa bacteria with the zone of inhibition 30, 31, 30, 30, and 30 mm, respectively, was achieved.