[en] Highlights: • Facile synthesis of tri-phase direct dual S-scheme ZnO–V₂O₅-WO₃ heterostructured NC and pure ZnO, V₂O₅, and WO₃ NPs. • SEM, EDX, XRD, Raman, FTIR, and UV–vis was carried out. • The photocatalytic performance was tested against MB, CR, RhB, MO, SO, and MR dyes. • S-scheme is more efficient than other schemes for enhancing photocatalytic activity. • The antibacterial test against different bacteria strain was performed. In this work, tri-phase direct dual S-scheme ZnO–V₂O₅–WO₃ heterostructured nanocomposite and pure ZnO, V₂O₅, and WO₃ nanoparticles were synthesized by using a facile co-precipitation approach to investigate antibacterial and photocatalytic characteristics of the grown nanocomposite. The physical properties of as-synthesized products were examined by employing characterization techniques such as Scanning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Raman, Fourier transform infrared spectroscopy (FTIR), and UV–vis spectroscopy. The XRD results confirmed the formation of pristine ZnO, V₂O₅, WO₃ nanoparticles and the existence of diffraction peaks related to hexagonal phase ZnO, orthorhombic V₂O₅, and monoclinic phase of WO₃ in ZnO–V₂O₅–WO₃ nanocomposite. The variation in structural parameters was studied by SSP, Scherrer plot, and W–H models. The energy bandgap of nanocomposite (2.63 eV) was calculated from UV–vis spectroscopy, which indicated the usability as a photocatalyst under direct sunlight. FTIR and Raman's spectra also supported the formation of the ZnO–V₂O₅–WO₃ nanocomposite. Spherical and roughly hexagonal morphology were seen in SEM images. EDX analysis has confirmed the existence of Zn, V, W, and O in the nanocomposite. The antibacterial test against Klebsiella pneumonia, Staphylococcus aureus, Proteus Vulgaris, and Pseudomonas aeruginosa bacteria showed higher activity. The photocatalytic performance of the ZnO–V₂O₅–WO₃ nanocomposite (99.8%) was the highest against methylene blue (MB) as compared to pure ZnO (78.8%), V₂O₅ (85.8%), and WO₃ (80.0%) under natural sunlight. The degradation efficiency of ZnO–V₂O₅–WO₃ against cresol red (CR), rhodamine-B (RhB), methyl orange (MO), safranin-O (SO), and methyl red (MR) dyes was 67.0%, 86.6%, 98.0%, 76.8%, and 99.0%, respectively, under direct sunlight in 80 min. Different schematic models are designed to illustrate the photocatalytic reaction mechanism, whereas the separation of charge carriers and enhanced photocatalytic performance can be efficiently explained by S-scheme.

[en] Highlights: • 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: 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_0.90Co_0.05Cr_0.05O (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.