Valluri Durga Kumari

Sm3+‐Doped Bi2O3 Photocatalyst Prepared by Hydrothermal Synthesis

Bi2O3 and Sm3+‐doped Bi2O3 visible‐light‐active photocatalysts with different Sm3+ loadings (0.5, 1.0, and 2.0 wt %) were synthesized by a hydrothermal method. The structural properties of the prepared catalysts were studied by X‐ray diffraction (XRD), BET surface area, UV/Vis diffuse reflectance (DRS), FTIR, and X‐ray photoelectron (XPS) spectroscopic techniques. The XRD spectra of the Sm‐doped Bi2O3 catalysts calcined at 550 °C show only the characteristic peaks of Bi2O3. A high red shift in the range 450–600 nm was detected in the DRS band, leading to a large decrease in the band‐gap energy from 2.82 to 2.0 eV. This red shift increased with increasing Sm content. XPS results revealed that Sm interacted with Bi2O3, wherein both Bi and Sm were in the +3 oxidation state. The photocatalytic activities of the catalysts were evaluated for the degradation of methylene blue and phenol under solar irradiation. Of all of the catalysts prepared, the Sm3+‐doped Bi2O3 with a Sm loading of 1 wt % gave the best photocatalytic activity.

An efficient and novel porous nanosilica supported TiO2 photocatalyst for pesticide degradation using solar light

A latex polymer of styrene-acrylic acid emulsion is used as a template for the synthesis of novel porous nanosilica (PNS) material. TiO(2) is dispersed over PNS by solid state dispersion and the composite materials are characterized by XRD, nitrogen adsorption-desorption isotherms, SEM and TEM measurements. The photocatalytic activities of the composite TiO(2)/PNS catalysts are evaluated for degradation of isoproturon pesticide in water with different parameters under solar light. Furthermore, commercial pesticide solutions containing imidacloprid and phosphamidon were also degraded successfully with the composite system using the same developed conditions for isoproturon degradation. The 5 wt% TiO(2)/PNS is found to be active in the present investigation.

Photocatalytic reduction of CO2 over Cu-TiO2 /molecular sieve 5A composite.

TiO2 and different Cu wt% loaded TiO2 (TC0.5–5.0), 10 wt% TC2.0 supported on molecular sieve 5A (10 wt% TC2.0/MS) were prepared by impregnation and solid‐state dispersion methods. The photocatalysts prepared were characterized using XRD, SEM, and UV–Vis DRS, TEM, XPS spectroscopy techniques. Photocatalytic reduction of CO2 in water and alkaline solution are investigated in a batch reactor. The yield of oxalic acid increased notably when TC was supported on molecular sieve. The Cu‐TiO2 supported on molecular sieve catalyst promotes the charge separation that leads to an increase in the selective formation of oxalic acid in addition to methanol, acetic acid and traces of methane. The product formation is due to the high adsorption of CO2, water and product shape selectivity of the composite photocatalyst. The maximum yield of oxalic acid was found to be 65.6 μg h−1 g−1 per cat using 0.2 N NaOH containing solution over 10 wt% TC2.0/MS photocatalyst. The difference in the photocatalytic activity is related to its physicochemical properties.

TiO2 supported over porous silica photocatalysts for pesticide degradation using solar light: Part 2. Silica prepared using acrylic acid emulsion.

An acrylic acid emulsion mixture is used for synthesis of novel porous silica (E-Si) material. The photocatalytic activity of TiO2 under solar light irradiation for isoproturon (herbicide) degradation is drastically increased when dispersed over E-Si support using solid state dispersion (SSD) technique. The composite material is characterized by XRD, nitrogen adsorption-desorption isotherms, UV-vis DRS, SEM and TEM measurements. The photocatalytic activities of the composite catalysts are evaluated for different parameters. The 5 wt% TiO2/E-Si is found to be highly active for isoproturon degradation.

Hydrogenation of acetophenone over bifunctional multi metal oxide catalysts

The vapor phase hydrogenation of acetophenone at atmospheric pressure is carried out for the synthesis of 1-phenylethanol in a fixed bed reactor using Cu-Zn-Al-O (LTS-1) and LTS-2, Zn-Cr-Al-O (HTS-1) and Zn-Cu-Cr-Al-O (HTS-2) metal oxide catalysts. Our studies clearly indicate that a catalyst of low temperature hydrogenation activity, when modified for its acidity with magnesium oxide, shows maximum selectivity of 1-phenylethanol.

Photocatalytic synthesis of urea from in situ generated ammonia and carbon dioxide.

TiO2 and Fe‐titanate (different wt%) supported on zeolite were prepared by sol‐gel and solid‐state dispersion methods. The photocatalysts prepared were characterized by X‐ray diffraction, scanning electron microscopy and ultraviolet (UV)–visible diffuse reflectance spectroscopy techniques. Photocatalytic reduction of nitrate in water and isopropanol/oxalic acid as hole scavengers are investigated in a batch reactor under UV illumination. The yield of urea increased notably when the catalysts were supported on zeolite. The Fe‐titanate supported catalyst promotes the charge separation that contributes to an increase in selective formation of urea. The product formation is because of the high adsorption of in situ generated CO2 and NH3 over shape‐selective property of the zeolite in the composite photocatalyst. The maximum yield of urea is found to be 18 ppm while 1% isopropanol containing solution over 10 wt% Fe‐titanate/HZSM‐5 photocatalyst was used.