Preparation of Mesoporous TiO2 Microspheres by Ultrasonic-Hydrothermal Process and its Photocatalysis

2012 ◽  
Vol 578 ◽  
pp. 99-104
Author(s):  
Yang Lin Liu ◽  
Xue Chen Duan ◽  
Shu Yun Liu ◽  
Yan Yan Liu
Keyword(s):  
Photocatalytic Activity ◽  
Crystal Size ◽  
High Surface ◽  
Hydrothermal Process ◽  
High Surface Area ◽  
Heat Treating ◽  
Mesoporous Tio2 ◽  
Average Crystal Size ◽  
Tio2 Microspheres ◽  
Effects Of Temperature

Mesoporous TiO2 microspheres were prepared by Ultrasonic-Hydrothermal Process with tetrabutyltitanate as titanium resource and octadecylamine as template. The effects of temperature and time of hytrothermol process, and calcination temperature on the structure had been investigated via XRD,SEM,TEM.The results indicated it will be better hythrothermol treating 20h at 120°Cand then heat-treating 4h at 400°C. A high surface area of 261.7 m2/g and pore volume of 0.28cm3/g was obtained in the corresponding sample with quite narrow distribution,and centering at 4.3nm in diameter.TiO2 frame was highly crystallized, showed the characteristic of pure anataste, with average crystal size of 10.0nm. The as-prepared sample possess a morphology of microspheres with diameter about 100-300nm.The photocatalytic activity was valuated by photodegradation of methly orange. The resultes indicated 99.79% of methly orange in the solution was removed after 30min photocatalytic treatment.

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.

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.

scholarly journals Photocatalytic Decolorization of Methyl Red on Nanoporous Anodic ZrO2 of Different Crystal Structures

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 215
Author(s):  
Ewa Wierzbicka ◽  
Karolina Syrek ◽  
Klaudia Mączka ◽  
Grzegorz D. Sulka
Keyword(s):  
Photocatalytic Activity ◽  
Photocatalytic Performance ◽  
Elevated Temperatures ◽  
Aqueous Electrolyte ◽  
High Surface ◽  
High Surface Area ◽  
Methyl Red ◽  
Self Organized ◽  
Photocatalytic Decolorization ◽  
Perfect Adhesion

High surface area, self-organized nanoporous ZrO2 arrays with perfect adhesion to the Zr substrate were synthesized by anodization in an aqueous electrolyte containing (NH4)2SO4 and NH4F. The obtained semiconductor materials were tested as photocatalysts for decolorization of the methyl red (MR) as a model azo dye pollutant. It was demonstrated that as-synthesized anodic ZrO2 anodic layers are already crystalline and, therefore, do not require further thermal treatment to provide a high photocatalytic performance. However, photocatalytic efficiency could be improved by annealing at a relatively low-temperature of 350 °C. Higher annealing temperatures caused a gradual drop of photocatalytic activity. The photocatalytic behavior was correlated with the crystal phase transformation in anodic ZrO2. It was found that higher photocatalytic activity was observed for the tetragonal phase over the monoclinic phase (predominant at elevated temperatures). It results from the optimal and complex electronic structure of annealed ZrO2 with three different energy states having absorption edges at 2.0, 4.01 and 5.28 eV.

Efficiency Enhancement in Dye-Sensitized Solar Cell Using TiO2 /Ilmenite-Derived Nanofiber Composite as Working Electrode

2014 ◽  
Vol 925 ◽  
pp. 600-604
Author(s):  
Athapon Simpraditpan ◽  
Thanakorn Wirunmongkol ◽  
Sorapong Pavasupree ◽  
Wisanu Pecharapa
Keyword(s):  
Nanocomposite Film ◽  
High Surface ◽  
Hydrothermal Process ◽  
High Surface Area ◽  
Dye Sensitized Solar Cells ◽  
Nanocomposite Films ◽  
Film Electrode ◽  
Photoelectric Conversion ◽  
Dye Sensitized ◽  
Working Electrode

TiO2 nanocomposite films of calcined TiO2 nanofibers and commercial-grade TiO2 nanoparticles Degussa (P25) utilized as working electrode of dye-sensitized solar cells (DSSCs) are prepared by a doctor blade method. TiO2 nanofibers were synthesized from ilmenite mineral by hydrothermal process in combination with calcinations process. The prepared samples are characterized by XRD, XPS and TEM. The photoelectric conversion performance of the DSSC based on nanocomposite film electrode was compared to the device fabricated by pure P25 at the same film thickness. The result shows that as calcination temperature increases, the transformation of nanofibers to nanorods and nanoparticles were observed. The energy conversion efficiency (ƞ) of the device tends to with increasing calcined temperature. The greatest ƞ is 3.90% obtained from DSSC fabricated from nanocomposite film electrode of 5 wt.% nanofibers calcined at 800 oC for 2 h mixed with P25, indicating the significant enhancement in its performance by the incorporation of the nanofibers. This enhancement of DSSCs may correlate to high surface area, higher light scattering and light harvesting, low charge recombination and fast electron-transfer rate by nanofibers.

Cr Doped TiO2 Supported on TUD-1 Photocatalyst for Dye Photodegradation

2014 ◽  
Vol 69 (5) ◽  
Author(s):  
Ooi Yee Khai ◽  
Leny Yuliati ◽  
Siew Ling Lee
Keyword(s):  
Photocatalytic Activity ◽  
Visible Light ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Xrd Analysis ◽  
Bandgap Energy ◽  
Doped Tio2 ◽  
Visible Light Driven ◽  
Synthesized Materials

New visible light driven photocatalysts of 1 mol% Cr doped TiO2 supported on TUD-1 have been successfully synthesized. The Cr-TiO2/xTUD-1 (x = 10, 20, 30, 40 and 50) photocatalysts were prepared via surfactant-free sol-gel method followed by wet impregnation procedures. XRD analysis revealed that both TiO2 and Cr were incorporated in the highly porous siliceous matrix. FTIR analysis showed the existence of Si-O-Ti in all the materials. As observed, tetrahedral-coordinated Ti species were dominant in Cr-TiO2/10TUD-1, Cr-TiO2/20TUD-1 and Cr-TiO2/30TUD-1. Meanwhile, octahedral- coordinated Ti species were the dominant species in Cr-TiO2/40TUD-1 and Cr-TiO2/50TUD-1. It has been demonstrated that the amount of TUD-1 as photocatalyst support affected the wavelength response and the bandgap energy of the resulting materials. All the materials have bandgap energy of ~2.9 eV. The photocatalytic performance of the synthesized materials was tested out in dye photodegradation under visible light irradiation at 298 K for 5 hours. Results showed that all Cr-TiO2/TUD-1 materials had higher photocatalytic activity than that of Cr-TiO2. This could be explained by the high surface area and porosity provided by TUD-1 in enhancing the adsorption and diffusivities of the dye molecules, hence leading to the promising photocatalytic activity. Among the materials prepared, Cr-TiO2/30TUD-1 appeared as the most superior photocatalyst which gave the highest dye photodegradation.

The synthesis of bayberry-like mesoporous TiO2 microspheres by a kinetics-controlled method and their hydrophilic films

CrystEngComm ◽  
2020 ◽  
Vol 22 (5) ◽  
pp. 969-978 ◽  
Author(s):  
Li Li ◽  
Liang Wang ◽  
Xinhong Chen ◽  
Changyuan Tao ◽  
Jun Du ◽  
...  
Keyword(s):  
Surface Roughness ◽  
High Surface ◽  
Mesoporous Tio2 ◽  
High Density ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
High Surface Roughness ◽  
Surface Hydroxyl Groups ◽  
Tio2 Microspheres

Bayberry-like mesoporous TiO2 hydrophilic films with high surface roughness and high density of surface hydroxyl groups.

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