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In this study, pure ZnO and iron (Fe) and cobalt (Co) co-doped ZnO nanoparticles were synthesized by varying Fe and Co concentrations using the co-precipitation method. The physical properties of as-prepared samples were investigated through XRD, FTIR, SEM, and UV–vis spectroscopy. X-ray diffraction confirmed the strong influence of Fe and Co ions on structural parameters without disturbing the basic ZnO hexagonal structure. The microstructural study was executed by using the Scherrer, W–H, and SSP methods. FTIR confirmed the presence of Zn–O, and Zn–M–O (M = Fe, Co) vibrational modes, which further confirmed the successful incorporation of dopants ions. The energy bandgap (E g) extracted from UV–vis spectra has shown red-shift (3.37–2.7 eV) for decreasing Fe contents, whereas blue-shift (3.37–3.39 eV) for increasing Co concentration. SEM was used to investigate surface morphology, which represents the high rate of agglomeration. The photocatalytic test was performed on grown samples against various dyes and also observed the effects of varying concentrations of Fe and Co ions. The maximum degradation efficiency (98.8%) at 6%Fe and 4%Co under direct sunlight in 60 min against methylene blue (MB) was achieved. The photocatalytic activity of optimized concentration (6%Fe and 4%Co) was further tested against cresol red (CR), methyl orange (MO), safranin-O (SO), rhodamine-B (RhB), and methyl red (MR) dyes. The maximum degradation efficiency against MR dye (96.0%) was observed. The antibacterial test against Staphylococcus aureus and Klebsiella pneumoniae bacterial strains have shown that co-doped ZnO nanoparticles have a higher activity as compared to pristine ZnO, and furthermore, the sample with 6%Fe and 4%Co concentration exposed the highest antibacterial actively for both bacterial strains. [ABSTRACT FROM AUTHOR]

Novel Zn 0 · 95 Mn 0 · 05 O and Zn 0 · 9 Mn 0.05 M 0.05 O (M = Al, Bi, Sr, Ag) nanocrystals were prepared via the co-precipitation technique. The X-ray diffraction pattern confirmed the substitution of Mn, Al, Bi, Sr, and Ag dopants without altering the basic ZnO structure. The microstructural study was performed by employing the Scherrer plot, Williamson-Hall, and SSP methods. The energy bandgap calculated from UV–vis spectra using different methods observed red-shifted by co-doping. The other optical parameters were also studied and discussed in detail. The FTIR spectra confirmed the presence of Zn–O, and Zn-M–O vibrational modes. Raman spectra demonstrated the presence of ZnO phonon modes, and the Raman shift exhibited the structural defects induced by dopants. The PL spectra showed strong NBE and DLE in the UV and visible region due to extrinsic defects. The IV measurements exhibited the enhancement in the electrical conductivity of ZnO by co-doping. The photocatalytic activity was performed under direct sunlight for methyl orange and methylene blue dyes, and the enhanced degradation efficiency was achieved by co-doping. Furthermore, this article enhances the understanding of tuning the physical properties of ZnO by co-doping and introduces a new class of sunlight-driven photocatalysts. [ABSTRACT FROM AUTHOR]

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 Cd 0.90 Co 0.05 Cr 0.05 O (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. [Display omitted] • Pristine CdO and Cr-Co co-doped CdO nanowires were synthesized via a facile co-precipitation method. • Different analytical techniques such as XRD, FTIR, Raman, UV–vis, IV, SEM, CV, EIS, and GCD were used. • Enhanced photocatalytic performance against various pollutants with stability upto 5th cycle was achieved. • Improved antibacterial characteristics against different human pathogenic bacterial strain was attained. • The higher specific capacitance, energy density, and power density at optimal loading of Cr and Co were obtained. [ABSTRACT FROM AUTHOR]