Cobalt-doped V2O5 hexagonal nanosheets for superior photocatalytic toxic pollutants degradation, Cr (VI) reduction, and photoelectrochemical water oxidation performance.

The worldwide energy calamity and ecological disturbances demand materials that can remove harmful contaminants from the polluted water. Recently, semiconductor-based catalytic dye removal has created much consideration due to its high efficacy and eco-friendly contaminated water treatment processes. Vanadium oxide (V2O5) has attracted superior attention as a catalyst due to its robust oxidation power, chemical inertness, and stability against photodegradation. In this study, pristine and cobalt (Co)-doped V2O5 samples were synthesized by solvothermal method and examined for their photo-degradation activity and photoelectrochemical (PEC) water oxidation properties. The orthorhombic crystal phase was confirmed by X-ray diffraction (XRD), hexagonal-shaped morphology was observed by scanning electron microscope (SEM) and reduced optical band gap (2.01 eV) was noticed for doped V2O5 catalyst compared to the pristine (2.20 eV) catalyst. The doped V2O5 catalyst exhibited enhanced photodegradation of crystal violet CV (92.7%) and Cr (VI) reduction (90.5%) after 100 min of light irradiation. The doped photocatalyst exhibited approximately 2.1 and 1.9-fold enhancement of photodegradation of CV and Cr(VI) reduction, respectively. The doped electrode showed improved photocurrent density (0.54 mA/cm-2) compared to pristine electrode (0.12 mA/cm-2). Moreover, the doped electrode showed reduced charge-transfer resistance and enhanced charge-transfer properties compared to those of the pristine electrode. Hence, the prepared hexagonal-shaped V2O5 is a suitable material for the elimination of environmental contaminants from the polluted water as well as water splitting for hydrogen generation.

Effect of Co(2+) and Ni(2+)-doped zinc borate nano crystalline powders by co-precipitation method.

A simple co-precipitation method has been used for the synthesis of Co(2+) and Ni(2+)-doped zinc borate nanopowders. X-ray diffraction (XRD), Fourier transform infrared (FT-IR), UV/Vis absorption, Scanning electron microscope (SEM) with EDS and photoluminescence (PL) spectroscopies techniques has been employed for their characterization. Powder X-ray diffraction data reveals that the crystal structure belongs to monoclinic for both as-prepared samples. SEM images showed surface morphology of the prepared samples. Optical absorption spectra showed the characteristic bands of doped ions in octahedral site symmetry. From the optical absorption data crystal field and inter-electronic repulsion parameters are evaluated. The FT-IR spectra showed the characteristic vibrational bands related to ZnO, BO3 and BO4 molecules. Photoluminescence spectra exhibited the emission bands in ultraviolet and blue regions.

Synthesis and structural characterization of Co2+ ions doped ZnO nanopowders by solid state reaction through sonication.

Cobalt ions doped zinc oxide nanopowder was prepared at room temperature by a novel and simple one step solid-state reaction method through sonication in the presence of a suitable surfactant Sodium Lauryl Sulphate (SLS). The prepared powder was characterized by various spectroscopic techniques. Powder XRD data revealed that the crystal structure belongs to hexagonal and its average crystallite size was evaluated. From optical absorption data, crystal fields (Dq), inter-electronic repulsion parameters (B, C) were evaluated. By correlating optical and EPR spectral data, the site symmetry of Co(2+) ion in the host lattice was determined as octahedral. Photoluminescence spectra exhibited the emission bands in ultraviolet and blue regions. The CIE chromaticity coordinates are also evaluated from the emission spectrum. FT-IR spectra showed the characteristic vibrational bands of Zn-O.

Synthesis and spectroscopic characterization of Cu(II) containing chlorocadmiumphosphate Cd(HPO4)Cl·[H3N(CH2)6NH3]0.5 crystals.

Chlorocadmiumphosphate Cd(HPO(4))Cl·[H(3)N(CH(2))(6)NH(3)](0.5) crystals containing Cu(II) ions have been successfully synthesized at room temperature by using organic amine 1,6-diamino hexane as a template. The samples are characterized by X-ray powder diffraction, Thermal and spectroscopic studies. These are crystallizes in the monoclinic crystal system with cell dimensions: a=1.7697, b=0.6576, c=1.9026nm and ß=106.5°. FT-IR spectrum showed the absorption bands related to PO(4), NH(3)(+) ions and other organic molecule vibrations originated from the templated molecule. The prepared crystals are stable at room temperature and as well as up to around 300°C which were confirmed by thermal analysis. Optical absorption and EPR studies suggest that Cu(II) ion enters in to the lattice as tetragonally distorted octahedral symmetry, for which crystal field and spin-Hamiltonian parameters are calculated. Bonding parameters are suggesting that there exists partial covalent nature between Cu(II) ions and ligands.