Photocatalytic Degradation of Acetaldehyde by Sol-Gel TiO2 Nanoparticles: Effect of the Physicochemical Properties on the Photocatalytic Activity

2011 ◽  
Vol 691 ◽  
pp. 92-98 ◽  
Author(s):  
R. Carrera ◽  
A.L. Vázquez ◽  
S. Castillo ◽  
E.M. Arce Estrada
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Surface Area ◽  
Photocatalytic Oxidation ◽  
Crystal Size ◽  
Uv Light ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Synthesis Method

Nowadays, nanostructured semiconductor materials offer promising opportunities for a new generation of materials such as TiO2nanoparticles with improved properties for their application in the environmental catalysis field. It is well known that the phocatalytic activity of the TiO2nanoparticles is strongly dependent on the surface area, crystal size, phase composition and synthesis method. Thus, the preparation conditions clearly affect the photocatalytic activity of the TiO2nanoparticles. This work deals with the study of the structure of TiO2nanoparticles that were synthesized by the sol-gel method (using isopropanol as solvent), and calcined at 200 and 500°C. The obtained samples were characterized by the XRD-Rietveld refinement, BET and TEM techniques; and tested in the photodecomposition of acetaldehyde. The evaluations were carried out at room temperature by using CH3CHO (300 ppmv), O2(2.0 %) in helium balance in a quartz glass photoreactor (gas phase) with a 365-UV light lamp. According to the results, the sample that presented the highest activity in the photocatalytic oxidation of acetaldehyde (96.4%) was the one annealed at 200 °C. This sample showed the following proportion of phases: anatase (62.88%) with a tetragonal structure (a=0.3790926, b=0.3790926, c=0.9495732) nm; and b) brookite (37.12%) with an orthorhombic structure (a=0.9167624, b=0.5416461, c=0.5210546) nm. The surface area was 189 m2/g and the average crystal size was 7.03 nm. From the results, it can be seen that this material showed high activity in the photocatalytic degradation of acetaldehyde because of: the presence of a mixture of the anatase (higher proportion) and brookite phases, nanometric crystal size and high surface area obtained in this TiO2material. According to the aforementioned, this material can be considered as a good option for the decomposition of acetaldehyde and other volatile organic compounds (VOCs) in confined spaces.

scholarly journals Enhancement of Photocatalytic Oxidation of Glucose to Value-Added Chemicals on TiO2 Photocatalysts by A Zeolite (Type Y) Support and Metal Loading

Catalysts ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 423 ◽  
Author(s):  
Kamonchanok Roongraung ◽  
Surawut Chuangchote ◽  
Navadol Laosiripojana
Keyword(s):  
Formic Acid ◽  
Surface Area ◽  
Gluconic Acid ◽  
Photocatalytic Oxidation ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Value Added ◽  
Incipient Wetness Impregnation ◽  
Microwave Assisted

TiO2-based photocatalysts synthesized by the microwave-assisted sol-gel method was tested in the photocatalytic glucose conversion. Modifications of TiO2 with type-Y zeolite (ZeY) and metals (Ag, Cu, and Ag-Cu) were developed for increasing the dispersion of TiO2 nanoparticles and increasing the photocatalytic activity. Effects of the TiO2 dosage to zeolite ratio (i.e., TiO2/ZeY of 10, 20, 40, and 50 mol %) and the silica to alumina ratio in ZeY (i.e., SiO2:Al2O3 of 10, 100, and 500) were firstly studied. It was found that the specific surface area of TiO2/ZeY was 400–590 m2g−1, which was higher than that of pristine TiO2 (34.38 m2g−1). The good properties of 20%TiO2/ZeY photocatalyst, including smaller particles (13.27 nm) and high surface area, could achieve the highest photocatalytic glucose conversion (75%). Yields of gluconic acid, arabinose, xylitol, and formic acid obtained from 20%TiO2/ZeY were 9%, 26%, 4%, and 35%, respectively. For the effect of the silica to alumina ratio, the highest glucose conversion was obtained from SiO2:Al2O3 ratio of 100. Interestingly, it was found that the SiO2:Al2O3 ratio affected the selectivity of carboxylic products (gluconic acid and formic acid). At a low ratio of silica to alumina (SiO2:Al2O3 = 10), higher selectivity of the carboxylic products (gluconic acid = 29% and formic acid = 32%) was obtained (compared with other higher ratios). TiO2/ZeY was further loaded by metals using the microwave-assisted incipient wetness impregnation technique. The highest glucose conversion of 96.9 % was obtained from 1 wt. % Ag-TiO2 (40%)/ZeY. Furthermore, the bimetallic Ag-Cu-loaded TiO2/ZeY presented the highest xylitol yield of 12.93%.

Sol-Gel Synthesis of N-Doped Mesoporous TiO2 with High Crystallinity and High Visible Light Photocatalytic Activity

2012 ◽  
Vol 217-219 ◽  
pp. 857-861 ◽  
Author(s):  
Xiao Ling Guo ◽  
Xiang Dong Wang ◽  
Feng He
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
Surface Area ◽  
Anatase Phase ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Weight Ratio ◽  
Mesoporous Tio2 ◽  
Vis Spectroscopy

N-doped mesoporous TiO2 with high surface area and crystallinity were synthesized by sol-gel method using polyacrylamide (PAM) and polyethylene glycol (PEG) as the complex templates. The resulting materials were characterized by XRD, TEM, N2 adsorption-desorption, and UV-Vis spectroscopy. It is found that when the weight ratio of PAM and PEG is 1:4, the sample, prepared at 600 °C in nitrogen and at 500 °C in air, is anatase phase and has high surface area and crystallinity. The particle size and pore size of the sample are about 10 nm and 17 nm respectively. Compared with that of the undoped mesoporous TiO2, the absorption band edges of N-doped samples exhibit an evident red-shift. The results of the photocatalytic degradation of methyl orange (MO) show that N-doped sample appears to have higher photocatalytic activity under visible light than undoped sample.

Role of Nanocrystalline Titania Phases in the Photocatalytic Oxidation of NO at Room Temperature

2010 ◽  
Vol 132 ◽  
pp. 96-104
Author(s):  
S. Castillo ◽  
R. Carrera ◽  
R. Camposeco ◽  
P. Del Angel ◽  
J.A. Montoya ◽  
...  
Keyword(s):  
Photocatalytic Oxidation ◽  
Room Temperature ◽  
Uv Light ◽  
Anatase Phase ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Nanocrystalline Tio2 ◽  
Oxidation Activity

Nanocrystalline TiO2 powders were prepared by the sol-gel method and evaluated in the NO photocatalytic oxidation. Samples annealed at 200 and 500°C (TiO2-P-200, TiO2-P-500) were characterized by nitrogen adsorption, XRD-Rietveld refinements, TEM, FTIR and UV-vis spectroscopies. The photocatalytic test of the sol-gel TiO2 samples was carried out in an insulated chamber with 10 ppm of NO, using a 365-nm UV light lamp; the test results were compared with those obtained with a commercial catalyst (P25). Improved photoactivity (89 % of NO oxidized in 60 min) was obtained with the TiO2-P-200 solid which showed high surface area, small crystallite size, higher amount of OH and highly abundant brookite phase (37.2 %) coexisting with the anatase phase (62.8 %). The photo-oxidation activity of the sol-gel catalyst annealed at 500 °C (TiO2-P-500) showed changes in its textural and morphologic properties and therefore, less photoactivity. Sol-gel photocatalysts could be a good option for abating pollution in both indoor and outdoor environments at room temperature.

High-Surface-Area Alumina-Silica Nanocatalysts Prepared by a Hybrid Sol-Gel Route Using a Boehmite Precursor

2010 ◽  
Vol 93 (12) ◽  
pp. 4047-4052 ◽  
Author(s):  
Padmaja Parameswaran Nampi ◽  
Padmanabhan Moothetty ◽  
Wilfried Wunderlich ◽  
Frank John Berry ◽  
Michael Mortimer ◽  
...  
Keyword(s):  
Surface Area ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area

Synthesis and structural characteristics of high surface area TiO2 aerogels by ultrasonic-assisted sol–gel method

2018 ◽  
Vol 29 (7) ◽  
pp. 075702 ◽  
Author(s):  
Feng Qingge ◽  
Cai Huidong ◽  
Lin Haiying ◽  
Qin Siying ◽  
Liu Zheng ◽  
...  
Keyword(s):  
Surface Area ◽  
Structural Characteristics ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Gel Method ◽  
Sol Gel Method ◽  
Ultrasonic Assisted

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.

Aqueous colloidal sol–gel route to synthesize nanosized ceria-doped titania having high surface area and increased anatase phase stability

2007 ◽  
Vol 43 (3) ◽  
pp. 299-304 ◽  
Author(s):  
Pradeepan Periyat ◽  
K. V. Baiju ◽  
P. Mukundan ◽  
P. Krishna Pillai ◽  
K. G. K. Warrier
Keyword(s):  
Surface Area ◽  
Phase Stability ◽  
Anatase Phase ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Doped Titania

Photocatalytically Active Cotton Fabrics Produced with Anatase Synthesized Using a Low-Temperature Sol-Gel Process

2018 ◽  
Vol 762 ◽  
pp. 408-412
Author(s):  
Raivis Eglītis ◽  
Gundars Mežinskis
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Sol Gel ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Average Particle ◽  
X Ray Diffraction ◽  
Sol Gel Process ◽  
Anatase Nanoparticles ◽  
Pre Treatment

In this work two different hydrosols were used to impregnate a commercially available cotton fabric with anatase nanoparticles to give it photocatalytic activity. To increase the activity, different pre-treatment methods were applied. The nanoparticle size was determined using dynamic light scattering and x-ray diffraction and the fabrics were examined using scanning electron microscopy. Photocatalytic activity was measured using the degradation of methyl-orange while irradiating the samples with UV light. The synthesis method allowed to produce anatase with an average particle size of 32 to 37 nm depending on the synthesis method used.

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