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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.

Metal oxide nanoparticles and their composites with conducting polymers, specifically Polyaniline (PANI) were utilized for fabricating nanoscale supercapacitor (SC) electrode materials. In the present study, we have synthesized pristine Pr2O3, NiO, Co3O4 nanoparticles, binary PANI-Pr2O3, PANI-NiO, PANI-Co3O4, ternary Pr2O3–NiO–Co3O4, and quaternary PANI-Pr2O3–NiO–Co3O4 spherical core-shell nanocomposite using co-precipitation and ultra-sonication methods. The grown samples were characterized with different analytical techniques. The XRD pattern revealed that the as-synthesized products were crystalline with Pr2O3 hexagonal phase, NiO cubic phase, and Co3O4 cubic phase in pure and nanocomposites. The Williamson-Hall, Scherrer, and size-strain plot methods were employed to study the crystalline development and contribution of micro-strain. FTIR pattern exhibited the metal-oxygen and PANI bond vibrations. FE-SEM images shown the spherical core-shell shape morphology of quaternary nanocomposite. EDX evident the presence of praseodymium, cobalt, and nickel in synthesized samples. UV–vis spectroscopy confirmed the absorption in the visible region. The IV graphs showed a higher conductivity of quaternary nanocomposite. The cyclic voltammetry results revealed that the quaternary nanocomposite has a higher specific capacitance 500 Fg-1 as compared to binary nanocomposites 134 F g−1 (PANI-Pr2O3), 143 F g−1 (PANI-Co3O4), 256 F g−1 (PANI-NiO), and PANI (90.8 F g−1) at a scan rate of 5 m Vs−1. The GCD results also showed that the quaternary nanocomposite has a higher specific capacitance of 905 F g−1 at current density 1 A g−1 with maximum energy density and power density of 87.99 kWhkg-1 and 2.6 k W kg−1, respectively. The EIS curve also confirmed that the quaternary nanocomposite has a lower polarization resistance (Rp) and solution resistance (Rs). The higher capacitance of quaternary nanocomposite can facilitate ion transfer, and the formation of its core-shell structure flourish to enhance surface-dependent electrochemical properties. Furthermore, this study gives a novel research idea to manufacture electrode materials for supercapacitors.

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.

Nowadays, environmental pollution due to discharge of organic pollutants from food, textile, and pharmaceutical industries into clean water and development of contagious diseases due to pathogenic organisms provide impetus to material researcher to fabricate novel design for efficient photocatalyst and antimicrobial agents. In this regard, designing a core-shell heterojunction catalyst based on metal oxides is considered an auspicious approach. In present study, combating the problems of singular oxides, core-shell PANI-CeO

Pristine CdO and chromium (Cr)-cobalt (Co) co-doped CdO nanowires via a facile co-precipitation protocol were synthesized and characterized with different analytical techniques to investigate its physical, photocatalytic, antibacterial, and electrochemical properties. The co-doping of Cr-Co into CdO matrix and their structural variations were confirmed by X-ray diffraction (XRD) data. Fourier transform infrared (FTIR) and Raman spectra also confirmed the doping of Cr and Co ions. The energy bandgap was extracted by employing different methods using UV–vis results, exhibited redshift by decreasing Co contents and blue shift by increasing Cr concentration. Scanning electron microscopy (SEM) images confirmed the preparation of nanowires. The photocatalytic and antibacterial experiments results showed the higher photodegradation efficiency against methylene blue (MB) (99.5%), methyl orange (MO) (90.6%), rhodamine-B (RhB) (87.5%), safranin-O (SF) (87.5%), and methyl red (MR) dyes (99.99%), after 60 min of sunlight illumination and the higher zone of inhibition (ZOI) against Klebsiella pneumoniae and Staphylococcus aureus for optimal doped Cd0.90Co0.05Cr0.05O (Cd4) sample. The recyclability tests using Cd4 catalyst were exhibited higher stability up to 5th cycles. The higher ability to decompose dyes and kill bacteria is due to the generation of reactive species, confirmed by the radical trapping experiments. The electrochemical measurements were revealed that the Cd4 sample has a higher specific capacitance of 500 F/ g− 1 at 10 mV/s scan rate, excellent energy density 72 Wh/Kg, and greater power density of 4800 W kg− 1 at a current density of 0.1 A/g. Furthermore, the properties of CdO can be tuned by co-doping for making it a useful material for photocatalyst, supercapacitors electrodes, and antibacterial applications.