scholarly journals Photocatalytic Degradation of Diclofenac Using Al2O3-Nd2O3 Binary Oxides Prepared by the Sol-Gel Method

Materials ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1345 ◽  
Author(s):  
José Eduardo Casillas ◽  
Jorge Campa-Molina ◽  
Francisco Tzompantzi ◽  
Gregorio Guadalupe Carbajal Arízaga ◽  
Alejandro López-Gaona ◽  
...  
Keyword(s):  
Band Gap ◽  
Uv Light ◽  
Light Exposure ◽  
Sol Gel ◽  
Reaction Times ◽  
Binary Oxide ◽  
Semiconductor Materials ◽  
Electron Hole ◽  
Binary Oxides ◽  
Sol Gel Synthesis

This paper reports the sol-gel synthesis of Al2O3-Nd2O3 (Al-Nd-x; x = 5%, 10%, 15% and 25% of Nd2O3) binary oxides and the photodegradation of diclofenac activated by UV light. Al-Nd-based catalysts were analyzed by N2 physisorption, XRD, TEM, SEM, UV-Vis and PL spectroscopies. The inclusion of Nd2O3 in the aluminum oxide matrix in the 10–25% range reduced the band gap energies from 3.35 eV for the γ-Al2O3 to values as low as 3.13–3.20 eV, which are typical of semiconductor materials absorbing in the UV region. γ-Al2O3 and Al-Nd-x binary oxides reached more than 92.0% of photoconverted diclofenac after 40 min of reaction. However, the photocatalytic activity in the diclofenac degradation using Al-Nd-x with Nd2O3 contents in the range 10–25% was improved with respect to that of γ-Al2O3 at short reaction times. The diclofenac photoconversion using γ-Al2O3 was 63.0% at 10 min of UV light exposure, whereas Al-Nd-15 binary oxide reached 82.0% at this reaction time. The rate constants determined from the kinetic experiments revealed that the highest activities in the aqueous medium were reached with the catalysts with 15% and 25% of Nd2O3, and these compounds presented the lowest band gap energies. The experimental results also demonstrated that Nd2O3 acts as a separator of charges favoring the decrease in the recombination rate of electron-hole pairs.

scholarly journals Room Temperature Synthesis of V-Doped TiO2 and Its Photocatalytic Activity in the Removal of Caffeine under UV Irradiation

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 911 ◽  
Author(s):  
Olga Sacco ◽  
Diana Sannino ◽  
Mariantonietta Matarangolo ◽  
Vincenzo Vaiano
Keyword(s):  
Room Temperature ◽  
Uv Light ◽  
Sol Gel ◽  
Doped Tio2 ◽  
Toc Removal ◽  
Calcination Step ◽  
Caffeine Degradation ◽  
Wavelength Emission ◽  
Sol Gel Synthesis ◽  
Uv Leds

In this work, the influence of simple acids in the room temperature sol-gel synthesis of TiO2 was investigated and the efficiency of prepared photocatalysts was evaluated in the removal of caffeine. To improve the photoactivity of TiO2, vanadium-doped TiO2 (VTiO2) samples were obtained starting from different amount of vanadyl sulphate as a dopant source. The samples were centrifuged, washed and finally dried at room temperature, and no calcination step was carried out. The prepared photocatalysts were characterized by different techniques (X-ray powder diffraction (XRD), specific surface area (SSA), ultraviolet-visible diffuse reflectance spectra (UV-vis DRS) and Raman). VTiO2 photocatalysts were tested in the photocatalytic removal of aqueous solutions containing caffeine. The photocatalytic tests were carried out in a recirculating batch cylindrical photoreactor irradiated by a UV LEDs strip (nominal power of 12 W and wavelength emission peak at about 365 nm) surrounding the external surface of the reactor. The optimized VTiO2 photocatalyst was able to reach a caffeine degradation of about 96% after 360 min of UV light irradiation with a total organic carbon (TOC) removal of 72%.

scholarly journals Zn Doped α-Fe2O3: An Efficient Material for UV Driven Photocatalysis and Electrical Conductivity

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 273 ◽  
Author(s):  
Suman ◽  
Surjeet Chahal ◽  
Ashok Kumar ◽  
Parmod Kumar
Keyword(s):  
Band Gap ◽  
Room Temperature ◽  
Uv Light ◽  
Sol Gel ◽  
High Energy ◽  
Lattice Parameter ◽  
Dielectric Behavior ◽  
Energy Storage Devices ◽  
Vis Spectroscopy ◽  
Potential Applications

Zinc (Zn) doped hematite (α-Fe2O3) nanoparticles with varying concentrations (pure, 2%, 4% and 6%) were synthesized via sol-gel method. The influence of divalent Zn ions on structural, optical and dielectric behavior of hematite were studied. X-ray diffraction (XRD) pattern of synthesized samples were indexed to rhombohedral R3c space group of hematite with 14–21 nm crystallite size. The lattice parameter (a and c) values increase upto Zn 4% and decrease afterwards. The surface morphology of prepared nanoparticles were explored using transmission electron microscopy (TEM). The band gap measured from Tauc’s plot, using UV-Vis spectroscopy, showed reduction in its values upto Zn 4% and the reverse trend was obtained in higher concentrations. The dielectric properties of pure and Zn doped hematite were investigated at room temperature and followed the same trends as that of XRD parameters and band gap. Photocatalytic properties of nanoparticles were performed for hazardous Rose bengal dye and showed effective degradation in the presence of UV light. Hence, Zn2+ doped hematite can be considered as an efficient material for the potential applications in the domain of photocatalysis and also higher value of dielectric constant at room temperature makes them applicable in high energy storage devices.

Band-Gap Engineering Based on Ti@ZnO Nanocolloids: Tunable Optical Properties

2014 ◽  
Vol 617 ◽  
pp. 161-165
Author(s):  
Chrystelle Neaime ◽  
Fabien Grasset ◽  
Tangi Aubert
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Uv Light ◽  
Sol Gel ◽  
Wide Band ◽  
Colloidal Solutions ◽  
Light Emitters ◽  
Wide Range ◽  
High Concentrations ◽  
Acoustic Wave Devices

One of the largest application areas of sol-gel chemistry is thin-film preparation. Using this approach, we started to synthesize M@ZnO colloidal solutions for the preparation of functional thin films. ZnO is a wide band-gap (3.37 eV) semiconductor with large exciton binding energy. In the bulk or in nanosized form, it could be used in a wide range of applications such as UV light emitters, spin functional devices, gas sensors, transparent electronics or surface acoustic wave devices. Since recently, the preparation of innovative functional M@ZnO materials by doping or functionalizing nanocolloids constitutes a new challenge. Using high concentrations of the different Ti@ZnO nanocolloids, we were able to prepare various functional colloidal solutions with tunable emission and thin films, such as red-luminescent Eu3+@ZnTiO3 or versatile ZnTiON colored nanomaterials.

Sol–gel synthesis of erbium-doped ZnO with nest structure for photocatalysis

2018 ◽  
Vol 11 (01) ◽  
pp. 1750082 ◽  
Author(s):  
Chun Li ◽  
Zuoyun Yan ◽  
Yuan Zhou ◽  
Shuang Zhao ◽  
Xiaotao Zhang ◽  
...  
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Kinetic Studies ◽  
Bandgap Energy ◽  
Nest Structure ◽  
Er Doping ◽  
Erbium Doped ◽  
Doped Zno ◽  
Er Doped ◽  
Sol Gel Synthesis

Rare earth erbium-doped ZnO samples were synthesized via a facile sol–gel method. The influences of Er-doping on structural properties, morphological features and optical properties were characterized by XRD, BET, SEM and UV–Vis DRS techniques. The results showed that the as-synthesized products were well crystallined in the absence of impurity phases and Er-doping resulted in the reduction of bandgap energy deducted from the UV–Vis DRS results. Amongst the samples, layer-like 0.5% Er-doped ZnO with nest structure achieved the highest photodegradation (90.7%) of methylene blue (MB) after UV light irradiation for 2[Formula: see text]h. The kinetic studies of MB degradation over different Er-doped ZnO were also conducted and proved to obey the pseudo-first-order kinetics.

Electrical Characteristic of UV Sensor Using Nanostructured Al Doped ZnO Thin Film

2013 ◽  
Vol 667 ◽  
pp. 384-387
Author(s):  
Mohamed Zahidi Musa ◽  
Mohamad Hafiz Mamat ◽  
Mohamad Rusop
Keyword(s):  
Absorption Coefficient ◽  
Near Infrared ◽  
Uv Light ◽  
Light Exposure ◽  
Sol Gel ◽  
High Sensitivity ◽  
Fast Response ◽  
Uv Sensor ◽  
Coating Method ◽  
Doped Zno

The electrical properties of nanostructured Aluminum (Al) doped Zinc Oxide (ZnO) thin films based ultraviolet (UV) sensor prepared by sol-gel spin-coating method have been investigated. Uniform nanoparticles Al doped ZnO have been deposited with high absorption coefficient at UV region and low absorption coefficient properties in visible and near-infrared (NIR) region. I-V spectra show high sensitivity characteristic of UV sensor with fast response after UV light exposure.

Correlation of Thickness with the Photocatalytic Characteristic of TiO2 Thin Films

2005 ◽  
Vol 486-487 ◽  
pp. 65-68 ◽  
Author(s):  
Sang Wook Lee ◽  
Hyun Suk Jung ◽  
Dong Wook Kim ◽  
Kug Sun Hong
Keyword(s):  
Thin Films ◽  
Film Thickness ◽  
Stearic Acid ◽  
Band Gap ◽  
Uv Light ◽  
Sol Gel ◽  
Photocatalytic Property ◽  
Tio2 Films ◽  
Tio2 Thin Films ◽  
Sol Gel Process

5, 10, and 30 nm thickness of transparent TiO2 thin films were fabricated using sol-gel process, and the influence of film thickness on the photocatalytic property was investigated. The increase in film thickness was found to enhance the photocatalytic property of the films. Photocatalytic properties of each film were estimated by decomposition of stearic acid. The amount of decomposed stearic acid increased with film thickness (5 - 30 nm). For the case of 30 nm thickness film, the stearic acid was decomposed perfectly in twelve minutes. UV-vis spectra and photocurrents of each film clearly showed that the photoactivities of TiO2 films were related to the amount of absorbed UV light and band gap shift.

ZnFe2O4 Doped TiO2 Photocatalyst Synthesis and Characterization with Effect of Different Coupling Ratios on Band Gap

2021 ◽  
Vol 43 (6) ◽  
pp. 736-736
Author(s):  
Farukh Iqbal Farukh Iqbal ◽  
Saad Nadeem Saad Nadeem ◽  
Kamran Zakaria and Bawadi Abdullah Kamran Zakaria and Bawadi Abdullah
Keyword(s):  
Visible Light ◽  
Band Gap ◽  
Uv Light ◽  
Sol Gel ◽  
Visible Region ◽  
Xrd Analysis ◽  
Phase Identification ◽  
Coupling Ratio ◽  
Color Mapping ◽  
Visible Light Driven

In this work the effect of different coupling ratios of ZnFe2O4 and TiO2 on the band gap was investigated, to convert TiO2 as a visible light driven photocatalyst ZnFe2O4. In this work, ZnFe2O4 was synthesized utilizing sol-gel technique and calcining under normal atmosphere at 900 and#176;C. Thereafter, ZnFe2O4 was coupled with TiO2 by mixing in 50 ml water in three different coupling w/w ratios (1:1, 1:2 and 2:1) followed by the calcination of coupled catalyst under nitrogen environment at 500 and#176;C. XRD, XPS, FESEM-EDS imaging, TGA, UV-Vis, and FTIR were performed to characterize the catalyst. Crystal phase identification could be confirmed through XRD analysis with homogenous distribution of metal constituents through color mapping and surface charge transitions from XPS analysis for a better electron hole generation. Thermogravimetric analysis (TGA) confirmed that the pure ZnFe2O4 obtained at 900 and#176;C, while FTIR verified the presence of desired functional group in ZnFe2O4. Moreover, Fourier Transformation Infrared Spectroscopy (FTIR) illustrated two major peaks and no extra major impurity was detected. ZnFe2O4 is visible light driven photocatalyst and TiO2 can work only under UV light. So, the effect of different coupling ratios of ZnFe2O4 with TiO2 was examined by UV-Vis characterization. The band gap is given by 1:1 was 2.8, 2:1 was 3.17 and 1:2 was 3.02. It was observed that the most optimum coupling ratio is 1:1 and the band-gap fall under visible region. The findings of this work could be supportive significantly for the selection of suitable coupling ratio to convert UV-driven photocatalyst into visible region active photocatalyst.

scholarly journals Investigation of the photocatalytic efficiency of tantalum alkoxy carboxylate-derived Ta2O5 nanoparticles in rhodamine B removal

2017 ◽  
Vol 8 ◽  
pp. 604-613 ◽  
Author(s):  
Subia Ambreen ◽  
Mohammad Danish ◽  
Narendra D Pandey ◽  
Ashutosh Pandey
Keyword(s):  
Rhodamine B ◽  
Uv Light ◽  
Sol Gel ◽  
Light Irradiation ◽  
Photocatalytic Efficiency ◽  
Uv Light Irradiation ◽  
Sol Gel Synthesis

Ta2O5 nanoparticles have been synthesized from alkoxy carboxylates of tantalum via the sol–gel route. Tantalum alkoxides were reacted with chlorocarboxylic acids in order to lower the susceptibility hydrolysis. When these modified alkoxy carboxylates were used in the sol–gel synthesis, they yielded Ta2O5 nanoparticles of better properties than those of the alkoxide-derived Ta2O5 nanoparticles. These nanoparticles efficiently removed rhodamine B under UV light irradiation.

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