Sol-gel preparation and characterization of Co/TiO2 nanoparticles: Application to the degradation of methyl orange

Abstract

Cobalt doped titania nanoparticles were synthesized by sol-gel method using titanium(IV) isopropoxide and cobalt nitrate as precursors. X-Ray diffraction (XRD) results showed that titania and Co/TiO 2 nanoparticles only include anatase phase. The framework substitution of Co in TiO 2 nanoparticles was established by XRD, scanning electron microscopy equipped with energy dispersive X-ray microanalysis (SEM-EDX) and Fourier transform infrared (FT-IR) techniques. Transmission electron microscopy (TEM) images confirmed the nanocrystalline nature of Co/TiO 2 . The increase of cobalt doping enhanced "red-shift" in the UV-Vis absorption spectra. The dopant suppresses the growth of TiO 2 grains, agglomerates them and shifts the band absorption of TiO 2 from ultraviolet (UV) to visible region. The photocatalytic activity of samples was tested for degradation of methyl orange (MO) solutions. Although the photocatalytic activity of undoped TiO 2 was found to be higher than that of Co/TiO 2 under UV irradiation, the presence of 0.5% Co dopant in TiO 2 resulted in a catalyst with the highest activity under visible irradiation.

Co/TiO2 nanoparticles: preparation, characterization and its application for photocatalytic degradation of methylene blue

“…3 at 0.6, 6.9 and 7.5 keV. The less intense peak is assigned to cobalt in the TiO 2 lattices [20,38]. These results confirmed the existence of cobalt atoms in the Co/TiO 2 samples but the XRD patterns do not show any diffractions related to cobalt.…”

“…In the case of Co/TiO 2 (d) sample, it can be concluded that the addition of cobalt to titania hinders the growth of TiO 2 nanoparticles. It seems that cobalt ions form complex with the TiO 2 surface oxygen, hence, suppress the growth of TiO 2 crystallite [38].…”

ESR and XRD investigation of effects induced by gamma radiation on PVA-TiO2 membranes

“…6b), [35]. When the concentration TiO 2 increases, these peaks appear again, but supplementary peaks appear at 2θ= 46…”

Synthesis and optical studies of gamma irradiated Eu doped nanocrystalline CaF2

“…With increase of Eu concentration from 1 mol% to 5 mol% the surface hydroxyl groups in the host (CaF 2 ) lattice are said to increase [10]. The increase in number of hydroxyl groups increase the intensity of FTIR absorption bands.…”