A series of solid base fly ash hybrid materials were synthesized by doping alkali, alkaline earth metals with nitrogen, separately using coprecipitation process, combined with surfactant incorporating method. The catalysts were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and photoluminescence spectroscopy. Results revealed that the co-doped hybrid materials are highly stable with particle size in the range of 40-60 nm. The surface basicity of fly ash was upraised by increased hydroxyl content by doping with alkali, alkaline earth metals with nitrogen. The basicity of hybrid material was measured by liquid phase, solvent free, single step condensation of 4-chlorobenzaldehyde and acetophenone giving higher conversion rate and selectivity of desired product chalcone. This conversion showed that the fly ash based hybrid material has sufficient basic site, responsible for the catalytic activity.

A series of novel photocatalyst with CdS loaded on activated carbon (xAC/CdS) were successfully synthesized by a simple hydrothermal method. The activated carbon content was varied between 0-7 wt. %. The prepared photocatalysts were characterized by X-ray diffraction, scanning electron microscopy with EDX, transmission electron microscopy, X-ray photoelectron spectroscopy, UV-Vis diffuse reflectance spectroscopy, N2 adsorption-desorption analysis and photoluminescence spectroscopy. The photocatalytic activity of as-synthesized photocatalysts was studied for RhB dye degradation under natural sunlight irradiation. XRD analysis assigned both cubic and hexagonal morphology for xAC/CdS photocatalysts. The UV-vis DRS studies showed that loading of CdS on activated carbon enhances its visible light absorption with decrease in band gap energy. The lowest photoinduced e/h pair recombination rate in 3wt% AC/CdS results in optimum photocatalytic activity as revealed by photoluminescence study. The enhancement in dye degradation ability (̴ 11 times) of prepared photocatalysts can be attributed to synergistic effect of CdS and activated carbon.

Abstract:We present a rapid, efficient one pot synthesis of [1,2,4]triazolo [5,1-b]

Boron (B), carbon (C) and sulphur (S) doped ZnO-SnO2 were successfully prepared by facile precipitation method. As prepared nanocomposite photocatalyst was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, high resolution transmission electron spectroscopy, Fourier transform infrared spectroscopy, photoluminescence spectra, UV-diffuse reflectance spectra and BET surface area measurement. The photocatalytic activity of prepared nanocomposite photocatalysts was studied by degradation of methyl orange dye under natural sunlight irradiation. S-doped ZnO-SnO2 was found to be more efficient than that of B,C-doped ZnO-SnO2 and bare ZnO-SnO2 nanocomposites. The photocatalytic activity of prepared photocatalysts follows trend as: S-doped ZnO-SnO2 > C-doped ZnO-SnO2 > B-doped ZnO-SnO2 > pure ZnO-SnO2. The enhanced activity of prepared photocatalysts could be attributed to the high specific surface area and small particle size.

A series of SnO2/activated carbon (AC) nanomaterials were prepared by co-doping V(III), Cr(III), Mn(II), Fe(III), Co(III), Ni(II), Cu(II), Zn(II) with nitrogen and sulphur, separately by co-precipitation method, combined with surfactant incorporation method. The as-prepared sample were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectra (XPS), Brunauer-Teller method (BET), diffuse reflectance spectroscopy (DRS), photoluminescence (PL) and Raman spectroscopy. The results showed that the phase composition, crystallite size, BET surface area and optical absorption of samples varied significantly with the nature dopants. The photocatalytic activities of these co-doped SnO2/AC catalysts were investigated by degradation rhodamine B in aqueous solution under solar-light illumination. The results showed an appreciable enhancement in the photoactivity of Fe/N/SnO2/AC as compared to other co-doped SnO2/AC because of smaller particle size, higher specific surface area, photogenerated carrier′s separation and solar light absorption. The degradation rate of rhodamine B dye reached 98 % in 30 min, which is about 10 times higher than that of pure SnO2.