Photocatalytic degradation of aqueous methyl orange using a novel Ag/TiO2/Fe2O3 photocatalyst prepared by UV-assisted thermal synthesis (original) (raw)
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Silver Doped TiO2 Photocatalyst for Methyl Orange Degradation
Journal of Engineering Science and Technology Review
The photocatalytic efficiency of nanocrystalline TiO 2 is strongly influenced by light sources and recombination of photoinduced electrons and holes. It is known that TiO 2 doped with Ag has self-sterilizing and self-cleaning effects. A study has been carried out on the photocatalytic behavior of silver modified titanium dioxide for decomposition of methyl orange after UV black lamps and solar irradiation treatment. The base nanoparticles were standard photocatalyst TiO 2 (P25). AgNO 3 aqueous solution with the presence of TiO 2 were irradiated with UV black lamps and reduced Ag doped the surface of the TiO 2 nanoparticles. The silver modified titanium dioxide particles were studied by XRD and TEM. Silver ions (Ag +) were reduced to Ag 0 as shown by the XRD. Silver particles of about 10 nm in size were detected on the surface of the TiO 2 and partially in the aqueous solution. The presence of Ag 0 on the surface of TiO 2 nanoparticles, after UV black lamps and solar irradiation, highly increased the photocatyalytic activity in comparison to the photocatalyst P25. This is explained with the reduced recombination of electrons and holes in the presence of Ag 0 .
Effect of Ag-N co-doping in Nanosize TiO 2 on Photocatalytic Degradation of Methyl Orange Dye
Journal of Surface Science and Technology, 2013
Synergetically modified nanosize TiO 2 semiconductor heterogeneous photocatalyst powder has been synthesized from TiCl 4 precursor for producing efficient photocatalyst that may work under visible radiation. The crystallite phase and size of the as-synthesized photo-catalyst were determined by X-ray diffraction (XRD) technique. As-synthesized TiO 2 was found to be nano-crystalline anatase. The absorption edge of the photo-catalyst was evaluated from the UV/ Visible diffuse absorbance spectra. The band gap energies (E bg ) of undoped-, Ag-doped-, Ndoped- and Ag-N co-doped TiO 2 semiconductor photo-catalysts were found to be 3.14, 3.02, 2.56 and 2.45 eV, respectively. Co-doping of Ag and N in TiO 2 has shown synergetic effect towards photo-catalytic degradation of methyl orange in aqueous solutions. Using Ag-N co-doped TiO 2 photo-catalyst, degradation of methyl orange under UV and visible irradiations were 79.1% and 73.5%, respectively.
2nd International Conference on Environmental Science and Technology, 2011
The objective of the present work was to synthesize 10 wt % metal doped TiO2 (Degussa P-25) photocatalysts using three methods: complex precipitation (CP), depositionprecipitation (DP) and wet impregnation (WI) methods and to evaluate their performance for a model azo dye, Orange II. The raw photocatalysts were activated by calcination at three different temperatures (180°C, 200°C and 300°C) for 1 hour duration. Photocatalytic degradation for 50 ppm orange II was studied at pH 6.8 under the irradiation of a UV light and visible light. The extent of dye degradation was determined using UV-vis Spectrophotometery. On the basis of results it was observed that visible light has better effect for dye removal compared to UV light and WI photocatalysts showed the best decolorization results with 100% Orange II removal for photocatalysts calcined at 1800C and 2000C while 98.5% for 3000C calcination temperature. Selected photocatalysts were characterized using Powder X-ray Diffraction (XRD), Fieldemission Scanning Electron Microscopy-Energy Dispersive Xray (FESEM- EDX) and Diffuse Reflectance UV visible spectroscopy (DRUV vis).
Journal of Electroanalytical Chemistry, 2020
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SN Applied Sciences
The aim of this work is the synthesis and characterization of C, N, S-Fe multidoped TiO 2 photocatalysts. The nanoparticles were prepared by sol-gel method and investigated by X-ray diffraction (XRD), transmission electron microscopy, UV-visible diffuse reflectance spectroscopy (DRS) and N 2 adsorption-desorption isotherm (BET). Photocatalytic activity of the photocatalysts was studied by degrading methyl orange (MO) under UV and visible light irradiations. XRD analysis illustrated that all synthesized samples present the anatase phase. CNS-0.3Fe-doped TiO 2 exhibited the highest surface area of 891 m 2 /g. DRS showed that Fe doping had efficiently narrowed the band gap to 2.74 eV and broaden the visiblelight response region. The synthesized nanomaterials exhibited high photodegradation ability in the decomposition of MO than commercial pure TiO 2 nanoparticles Degussa P25.
Environmental Technology & Innovation, 2018
The photocatalytic degradation of a model azo dye acid orange 7 (AO7) by Fe 3+-doped TiO 2 nanocatalyst has been studied under UV, Visible (λ > 400 nm) and solar light irradiation. The role of hydrogen peroxide to enhance the catalyst's efficiency was examined. The reaction pathway of complete mineralization was investigated by monitoring the temporal evolution of reaction intermediates and low molecular weight organic acids (LMWOA) as final products in solution. These LMWOAs are oxidized eventually to inorganic ions such a nitrate, sulfate, oxalate etc, which are confirmed using GC-MS, UV-Vis and Ion Chromatographic analyses. The optimized condition of photocatalytic degradation were obtained for degradation under different light source. The Fe 3+-doped TiO 2 showed high dye degradation efficiency under both UV (100%), visible (100%) and solar light (90%) which distinguishes Fe 3+-doped TiO 2 from materials in literature that are only efficient in particular light source for dye degradation. Furthermore, the Fe 3+ doped titania photocatlysts are stable and can maintain performance upto 6 recycle use. Reaction kinetics for UV and solar light induced degradation followed first order reaction whereas visible light degradation followed a zero-order reaction.
Journal of Environmental Sciences, 2017
A nitrogen-doped titanium dioxide composite photocatalyst (N-TiO 2) with heterojunction structures is synthesized by three different approaches: a novel UV-assisted thermal synthesis, annealing, and microwave technique. Photocatalytic activities of synthesized photocatalysts are evaluated by the degradation of Methyl Orange under ultraviolet light types A (UV-A), B (UV-B), and C (UV-C), visible light, and direct sunlight irradiation. Results show that by using N-TiO 2 photocatalyst prepared by the UV-assisted thermal synthesis and annealing, the degradation increases by 16.5% and 20.4%, respectively, compared to that by bare TiO 2. The best results are obtained at a nitrogen to TiO 2 mass ratio of 0.15 (N: TiO 2). The enhancement of the photocatalytic activity observed in the visible range is mainly attributed to the increasing separation rate of photogenerated charge carriers. The novel UV-assisted thermal synthesis has produced encouraging results as a preparation method for the nitrogen-doped TiO 2 photocatalyst; thus, further studies are recommended for process optimization, immobilization, and scale-up to evaluate its applicability in wastewater treatment.
N-Loaded TiO2 for Photocatalytic Degradation of Methyl Orange under Visible Light Irradiation
Advanced Materials Research, 2012
Nitrogen-loaded TiO2 (N-loaded TiO2), a visible-light driven catalyst, was successfully synthesized by the modified sol-gel method. Physical characterizations of the as-prepared catalysts have been performed by using X-ray diffraction (XRD), Diffuse reflectance UVvisspectroscopy(DRUVvis), Raman spectroscopyand BETspecific surface areain order to obtain structure-activity relationship. Results from Raman spectroscopy clearly suggested that N atoms were incorporated into the TiO2 crystal lattice as evidenced by the vibrational peak of TiN in TiO2-xNx.DR UVvis results also suggested that the nitrogen dopant might be responsible for narrowing the TiO2band gap energy, thus resulting in a shift towards the visiblelight region. Photocatalytic activity of N-loaded TiO2 evaluated through the degradation of methyl orange (MO)under visible light irradiation (l> 400 nm) indicated that all N-loaded photocatalysts exhibited significantly higher activities than the unloaded TiO2 and Degussa...
2015
This study describes the application of novel chemistry methods for the removal of dye by nano-structured titanium oxide (TiO 2) photocatalysts. Such materials can be applied in the development of efficient photocatalytic systems for the treatment of water. Nanocrystalline TiO 2 was synthesized by Sol-Gel route using titanium tetraisopropoxide as a metal precursor. The catalysts were characterized by X-ray diffraction (XRD), Transmission Electron Microoscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR). Synthesized TiO 2 was related to anatase phase and crystalline structure was characterized by XRD. Cuboidal and uneven shape of TiO 2 nanoparticles were observed by TEM images. FTIR reveals the functional groups present in the synthesized TiO 2 nanoparticles. Thus synthesized TiO 2 nanoparticle was used for photocatalytic degradation of methyl orange. The photodegradation of methyl orange (MO) dye, is examined both under different dye concentration(10,20,30 and 40 ppm) and ...