scholarly journals Vanadium oxides doped porous titania photocatalysts for phenol photodegradation

2016 ◽  
Vol 12 (1) ◽  
Author(s):  
Siew Ling Lee ◽  
Swee Por Khaw ◽  
Yee Khai Ooi
Keyword(s):  
Anatase Phase ◽  
Sol Gel ◽  
Phenol Degradation ◽  
Nitrogen Adsorption ◽  
Band Gap Energy ◽  
Vanadium Oxides ◽  
Ammonium Bromide ◽  
Porous Titania ◽  
Cetyltrimethyl Ammonium ◽  
Adsorption Desorption

Vanadium oxides (1 - 5 wt%) doped porous TiO2 using tetrabutyltitanate and cetyltrimethyl ammonium bromide as Ti precursor and template, respectively was successfully synthesized via sol-gel method. All the samples crystallined in anatase phase as indicated by X-ray diffraction analysis. The results of diffused reflectance UV-visible spectroscopy analysis showed that the band gap energy of TiO2 reduced from 3.02 to 2.72 eV after introduction of 5 wt% V. The nitrogen adsorption-desorption analysis revealed that the surface area of samples increased with the amount of V dopant. These materials contained of disorder mesopores with particle size ranged 5 – 56 nm. Amongst, sample 4V-TBT-p-TiO2 recorded the highest percentage of phenol degradation (62.2%) under visible light irradiation

scholarly journals Synthesis of Ag-TiO2/perlite composite for the photodegradation of methylene blue under solar light irradiation

2020 ◽  
Vol 9 (4) ◽  
pp. 42-48
Author(s):  
Nui Pham Xuan ◽  
Hoa Nguyen Thi ◽  
Tien Nguyen Trung ◽  
Tai Le Huu ◽  
Thi Tran Thi Van
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Diffuse Reflectance Spectroscopy ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Band Gap Energy ◽  
Light Irradiation ◽  
Solar Light ◽  
Solar Light Irradiation ◽  
Adsorption Desorption

In this research, photocatalytic materials of TiO2, Ag-TiO2, Ag-TiO2/perlite were synthesized by the sol-gel method. By combining the photocatalytic activity between Ag-TiO2 and Perlite mineral, the Ag-TiO2/perlite composite has overcome the disadvantages of pristine TiO2, such as high band gap energy, low light utilization and easy recombination of electrons and holes. The synthesized samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption isotherm, UV-vis diffuse reflectance spectroscopy (UV-vis DRS). The photocatalytic activity of the samples was tested for degradation of methylene blue (MB) under solar light irradiation. Photodegradation studies revealed a 95% removal of MB dye via the synthesized Ag-TiO2/perlite after 150 min of irradiation. Reusability of this hybrid photocatalyst system was tested and only a 3% decrease was observed after four cycles.

scholarly journals Modification of TiO2 nanoparticles through lanthanum doping and peg templating

2014 ◽  
Vol 8 (4) ◽  
pp. 195-202 ◽  
Author(s):  
Marija Milanovic ◽  
Ljubica Nikolic
Keyword(s):  
Anatase Phase ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Sem Analysis ◽  
X Ray Diffraction ◽  
Average Pore ◽  
Lanthanum Doping ◽  
X Ray ◽  
Doped Titania ◽  
Adsorption Desorption

Pure and lanthanum doped titania nanopowders were synthesized through a room temperature sol-gel method using a template of polyethylene glycol (PEG). The progress of the synthesis in terms of phase formation and size of nanoparticles was monitored by X-ray diffraction, FTIR spectroscopy and SEM analysis. After calcination at 450?C in air, the results have shown the presence of small particles crystallized predominantly in the form of anatase phase, with significant agglomeration. Nitrogen adsorption-desorption measurements confirmed that all prepared powders are mesoporous with an average pore diameter in range 3.1-3.8 nm. The addition of lanthanum ions leads to the nanopowders with the highest specific surface (BET) area (203m2/g). The obtained powders were compared to TiO2 prepared without a template.

Adsorptive Desulfurization of Model Gasoline on Organic - Inorganic Modified Montmorillonite

2014 ◽  
Vol 875-877 ◽  
pp. 237-241 ◽  
Author(s):  
Yu Chang Zhang ◽  
Xiao Wei Yang ◽  
Dan Li ◽  
Ping Na
Keyword(s):  
Adsorption Mechanism ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Material Structure ◽  
Ammonium Bromide ◽  
Maximum Adsorption Capacity ◽  
X Ray Diffraction ◽  
Adsorptive Desulfurization ◽  
Nmr Techniques ◽  
Adsorption Desorption

The phenyl trimethyl ammonium bromide (PTMAB) and Keggin polyhydroxyl aluminum cations (Al13) as pillared agent and montmorillonite as the carrier, organic - inorganic pillared montmorillonite was prepared through sol-gel method to remove sulfur in model gasoline. The results showed when adsorption time was 1.5 h and reaction temperature was 40 °C, the maximum adsorption capacity of PTMAB-Al-MMT was 5.32 mg/g. The modified materials were characterized by X-ray diffraction, Nitrogen adsorption-desorption and NMR techniques to investigate the material structure and the adsorption mechanism. After the intercalation of PTMAB and Keggin Al13 in MMT, the interlayer d-spacing, specific surface and pore volume area increased to 1.10 nm, 41.23 m2 /g and 0.16cm3/g, respectively.

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

scholarly journals Bulk Versus Surface Modification of Alumina with Mn and Ce Based Oxides for CH4 Catalytic Combustion

Materials ◽  
2019 ◽  
Vol 12 (11) ◽  
pp. 1771 ◽  
Author(s):  
Stefan Neatu ◽  
Mihaela M. Trandafir ◽  
Adelina Stănoiu ◽  
Ovidiu G. Florea ◽  
Cristian E. Simion ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Catalytic Combustion ◽  
Mixed Oxides ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Temperature Programmed ◽  
Catalytic Combustion Of Methane ◽  
Adsorption Desorption

This study presents the synthesis and characterization of lanthanum-modified alumina supported cerium–manganese mixed oxides, which were prepared by three different methods (coprecipitation, impregnation and citrate-based sol-gel method) followed by calcination at 500 °C. The physicochemical properties of the synthesized materials were investigated by various characterization techniques, namely: nitrogen adsorption-desorption isotherms, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and H2–temperature programmed reduction (TPR). This experimental study demonstrated that the role of the catalytic surface is much more important than the bulk one. Indeed, the incipient impregnation of CeO2–MnOx catalyst, supported on an optimized amount of 4 wt.% La2O3–Al2O3, provided the best results of the catalytic combustion of methane on our catalytic micro-convertors. This is mainly due to: (i) the highest pore size dimensions according to the Brunauer-Emmett-Teller (BET) investigations, (ii) the highest amount of Mn4+ or/and Ce4+ on the surface as revealed by XPS, (iii) the presence of a mixed phase (Ce2MnO6) as shown by X-ray diffraction; and (iv) a higher reducibility of Mn4+ or/and Ce4+ species as displayed by H2–TPR and therefore more reactive oxygen species.

scholarly journals ZnFe2O4-TiO2Nanoparticles within Mesoporous MCM-41

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Aidong Tang ◽  
Yuehua Deng ◽  
Jiao Jin ◽  
Huaming Yang
Keyword(s):  
Sol Gel ◽  
Rutile Phase ◽  
Band Gap Energy ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Agglomeration Of Nanoparticles ◽  
Adsorption Desorption ◽  
Mcm 41

A novel nanocomposite ZnFe2O4-TiO2/MCM-41 (ZTM) was synthesized by a sol-gel method and characterized through X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), N2adsorption-desorption, Raman spectroscopy, and ultraviolet visible (UV-vis) spectrophotometry. The results confirmed the incorporation of ZnFe2O4-TiO2nanoparticles inside the pores of the mesoporous MCM-41 host without destroying its integrity. ZnFe2O4nanoparticles can inhibit the transformation of anatase into rutile phase of TiO2. Incorporation of ZnFe2O4-TiO2within MCM-41 avoided the agglomeration of nanoparticles and reduced the band gap energy of TiO2to enhance its visible light photocatalytic activity. UV-vis absorption edges of ZTM nanocomposites redshifted with the increase of Zn/Ti molar ratio. The nanocomposite approach could be a potential choice for enhancing the photoactivity of TiO2, indicating an interesting application in the photodegradation and photoelectric fields.

Cement Bonded Sol-Gel TiO2 Powder Photocatalysis for Phenol Removal

2015 ◽  
Vol 776 ◽  
pp. 271-276 ◽  
Author(s):  
Nor Hafizah ◽  
Iis Sopyan
Keyword(s):  
Anatase Phase ◽  
Sol Gel ◽  
Phenol Degradation ◽  
Xrd Analysis ◽  
Hydrolysis Rate ◽  
Molar Ratio ◽  
Synthesis Process ◽  
Phenol Removal ◽  
Titanium Tetraisopropoxide ◽  
Degussa P25

Photocatalysis has been proven effective in controlling various environmental problems originated by pollutions both in liquid and gaseous phases. Titanium dioxide (TiO2) is well known the most practical photocatalyst as it has high photocatalytic efficiency, low band gap energy, and no toxicity. Various chemical methods have been tried to produce TiO2 photocatalyst powder with high activity. In this study, sol-gel method has been employed to produce nanosized TiO2 photocatalyst particles and its physical properties and photocatalytic activity in phenol degradation test were compared with the commercial TiO2 powder, Degussa P25. The synthesis process was carried out through hydrolysis of titanium tetraisopropoxide (TPT) and methanol where the molar ratio of water to TPT was monitored to control the hydrolysis rate. From X-Ray Diffraction (XRD) analysis, the sol-gel TiO2 powder obtained was fully in anatase structure with high crystallinity. Scanning Electron Microscope (SEM) measurement showed that the powder was in nanoto sub-micron size, spherical in shape, and tightly agglomerated. Thermal analysis confirmed that sol-gel derived amorphous TiO2 powder transformed to anatase phase after 400°C calcination. The test on photocatalytic performance conducted using aqueous solution of phenol as the representative of water pollutant examined in this study showed that the sol-gel TiO2 powder is more efficient in degrading phenol compared to one of the most active photocatalysts commercially available, Degussa P25.

Self-Organization in Nanoparticle Titanium Dioxide Thin Films

1998 ◽  
Vol 519 ◽  
Author(s):  
S.D. Burnside ◽  
V. Shklover ◽  
C.A. Barbe ◽  
K. Brooks ◽  
P. Comte ◽  
...  
Keyword(s):  
Thin Films ◽  
Titanium Dioxide ◽  
Sol Gel ◽  
Photovoltaic Performance ◽  
Nitrogen Adsorption ◽  
Self Organization ◽  
X Ray Diffraction ◽  
Nanocrystalline Titanium ◽  
Titanium Dioxide Thin Films ◽  
Adsorption Desorption

AbstractNanocrystalline titanium dioxide has been synthesized using a sol-gel technique followed by hydrothermal growth at temperatures in the range 190-270°C. Thin films of these colloids were studied using x-ray diffraction (XRD), scanning electron microscopy (SEM), and nitrogen adsorption/desorption. Self-organization of the nanocrystalline particles in regular arrays was observed in films made from colloids autoclaved at lower temperatures. We present herein initial photovoltaic performance of these semiconducting films used as working electrodes in a dye-sensitized solar cell.

scholarly journals Surfactant-Free Solvothermal Method for Synthesis of Mesoporous Nanocrystalline TiO2Microspheres with Tailored Pore Size

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Yajing Zhang ◽  
Sujuan Zhang ◽  
Kangjun Wang ◽  
Fu Ding ◽  
Jing Wu
Keyword(s):  
Pore Size ◽  
Anatase Phase ◽  
Nitrogen Adsorption ◽  
Ethanol Solution ◽  
Tetrabutyl Titanate ◽  
Size Distributions ◽  
Pore Size Distributions ◽  
Structure Morphology ◽  
Mesoporous Microspheres ◽  
Adsorption Desorption

TiO2mesoporous microspheres self-assembled from nanoparticles were synthesized by a surfactant-free solvothermal route. The TiO2precursors were fabricated by tetrabutyl titanate, glacial acetic acid, and urea in the ethanol solution at 140°C for 20 h, and TiO2mesoporous microspheres were obtained by a postcalcination at temperatures of 450°C for promoting TiO2crystallization and the removal of residual organics. The phase structure, morphology, and pore nature were characterized by XRD, SEM, and nitrogen adsorption-desorption measurements. The as-prepared TiO2microspheres are in anatase phase, with 2-3 μm in diameter, and narrow pore distribution range is 3-4 nm. The adjustments of the synthetic parameters lead to the formation of the mesoporous TiO2microspheres with tuned pore size distributions and morphology.

scholarly journals Characterization and Photocatalytic Activity of Nano-TiO2 Doped with Iron and Niobium for Turquoise Blue Dye Removal

2012 ◽  
Vol 12 (1) ◽  
pp. 34 ◽  
Author(s):  
Nhat Minh Doan ◽  
Carl Renan Estrellan ◽  
Anton Purnomo ◽  
Susan Gallardo ◽  
Chris Salim ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Anatase Phase ◽  
Sol Gel ◽  
Chemical Properties ◽  
Band Gap Energy ◽  
Blue Dye ◽  
Nano Tio2 ◽  
Co Doping ◽  
Reaction Rate Constants ◽  
Physical And Chemical

The nano-TiO2 photocatalysts doped with Iron and Niobium for dye wastewater treatment were prepared by temperature-controlled sol-gel method. The effects of these dopants on the physical and chemical properties of TiO2 were compared with the commercially available Degussa TiO2 P25. Among these characteristics are crystalline size, the presence of absolute anatase phase, band gap energy and specific surface area. The characterization data were correlated to photocatalytic activities using Turquoise blue dye (TBD) as model pollutant. Single doping (with Nb) and co-doping (Fe and Nb) catalyst reached complete decolorization within 2.5 hours and 3 hours. In addition, their kinetic reaction rate constants of apparent first-order model are 0.0258 min-1 and 0.0225 min-1, respectively. The presence of Nb as traps is considered to play a crucial key in enhancing the photocatalytic activity.

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