The Study on the Decomposition of Azo Dye by La-Modified TiO2

2010 ◽  
Vol 123-125 ◽  
pp. 276-279
Author(s):  
Kuo Shan Yao ◽  
Yung Hsu Hsieh ◽  
Yu Jie Chang ◽  
Ching Hsing Lin ◽  
Chen Yu Chang ◽  
...  
Keyword(s):  
Azo Dye ◽  
Acidic Solution ◽  
Supported Catalysts ◽  
Anatase Phase ◽  
Sol Gel ◽  
Rutile Phase ◽  
Desorption Process ◽  
Sol Gel Process ◽  
Photocatalytic Activities ◽  
20 Nm

The La/TiO2 photocatalyst was prepared by lanthanum into TiO2 structure in a sol-gel process. The catalyst was characterized by field-emission scanning electron microscope (FE-SEM), X-ray diffractometer (XRD), ESCA, and Brunauer Emmett Teller (BET) analyses. Photocatalytic activities of the supported catalysts were examined through decomposition process of azo-dye Acid Yellow 17 solution under UV irradiation. The results showed that the particle size of TiO2 is about 20 nm, and the particle of La/TiO2 is about 10 nm. The crystal structure is mainly in anatase phase, the contents of the rutile phase increase with the increase of the amount of doped lanthanum. The adsorption capacity of La/TiO2 catalysts increases with lanthanum dosage in the acidic solution. The contribution of actual photodecomposition was determined by desorption process, after the photocatalytic reaction. In the acidic solution, better photodecomposition efficiency is achieved than in the neutral or alkaline solution. The experiments demonstrated that the optimum doping of La at 10 mol %, the maximum photodecomposition in dye concertration at 15 mg L-1 and photocatalytic dosage at 0.75 g L-1, achieving the highest effect.

Sol-Gel Synthesis and Characterization of TiO2-Based Photocatalyst and its Photoactivity Research

2013 ◽  
Vol 864-867 ◽  
pp. 613-616
Author(s):  
Xue Mei Qi ◽  
Xin Yuan Zhu ◽  
Jiang Wu ◽  
Yu Wu ◽  
Han Cheng Luo
Keyword(s):  
Anatase Phase ◽  
Sol Gel ◽  
Great Influence ◽  
Rutile Phase ◽  
Xrd Diffraction ◽  
Sol Gel Process ◽  
Photocatalytic Activities ◽  
Stirring Time ◽  
Sol Gel Synthesis

The TiO2-based photocatalysts have been synthesized by using sol-gel process and their photocatalytic activities were studied by the degradation of methylene blue (MB). It was shown that the calcination temperature has great influence on the crystalline phase transition of TiO2. For all the samples (Ag-doped and undoped TiO2photocatalysts) calcined at 573K, only anatase phase was observed from XRD diffraction spectra and the intensity of peaks is weak. After the calcined at 773K, a mixture of anatase-rutile phase appeared. The contents of rutile phase were about 85% and77% for undoped and Ag-adopted TiO2photocatalysts.There were only rutile phases for all the TiO2photocatalysts calcined at 973K observed from XRD diffraction spectra. Magnetically stirring time of A solution before added B had no obvious effects on the polymorphs transition of TiO2.

Preparation of Ti/B Binary Oxides by Sol-Gel Method and Their Photocatalytic Activity for Stoichiometric H2O Decomposition

1996 ◽  
Vol 454 ◽  
Author(s):  
S. C. Moon ◽  
S. Tabata ◽  
K. Okada ◽  
M. Fujiki ◽  
H. Mametsuka
Keyword(s):  
Titanium Oxide ◽  
Anatase Phase ◽  
Aqueous Suspension ◽  
Sol Gel ◽  
Rutile Phase ◽  
Binary Oxide ◽  
Gel Method ◽  
Sol Gel Method ◽  
Binary Oxides ◽  
Photocatalytic Activities

ABSTRACTA titanium-boron binary oxide has been prepared by the sol-gel method and characterized using SEM, TEM, UV-VIS reflectance, and X-ray diffraction spectroscopies. These measurements indicated that the obtained Ti/B gel with no treatment exhibited an amorphous structure. After calcination in O2, the crystalline structure of titanium oxide species in the Ti/B binary oxide was changed while boron oxide species maintained in the state of amorphous. Titanium oxide species in the Ti/B binary oxide calcined at 673 K showed an anatase phase of TiO2, and changed with the calcination temperatures from anatase phase to rutile phase. The Pt loaded Ti/B photocatalysts in aqueous suspension system decomposed water stoichiometrically under UV-irradiation. Their photocatalytic activities decreased with increasing the calcination temperature, indicating the photocatalytic activities of the Ti/B binary oxides were depended on the crystal phase of titanium oxide in the Ti/B photocatalysts.

Experimental Research on Degradation of Azo Dye Wasterwater by Photocatalysis of Nano-TiO2 Doped with Ce / Fe

2013 ◽  
Vol 295-298 ◽  
pp. 331-334 ◽  
Author(s):  
Hong Jiao Song ◽  
Lei Zhu ◽  
Xun Wang
Keyword(s):  
Photocatalytic Activity ◽  
Experimental Research ◽  
Azo Dye ◽  
Sol Gel ◽  
Dye Wastewater ◽  
Photogenerated Electrons ◽  
Sol Gel Process ◽  
Degradation Of Azo Dye

The sol-gel process is applied to respectively prepare nano-TiO2films with Ce (cerium) or nano-TiO2films with Fe (ferium), which are used to degradate azo dye wastewater and present their characterization by XRD and HRTEM methods. The results show that proper amount of Ce or Fe doped into the nano-TiO2films can effectively accelerate the separation of photogenerated electrons-holes and easily form lattices, and consequently promotes nano-TiO2films' photocatalytic activity by nearly 20%.

Metal supported catalysts obtained by sol-gel in the hydrosilylation of phenylacetylene with R3SiH organosilanes (R3 = Ph3, Ph2Me, and PhMe2)

2000 ◽  
Vol 78 (11) ◽  
pp. 1491-1495 ◽  
Author(s):  
Rafael Jiménez ◽  
Juan Manuel López ◽  
Jorge Cervantes
Keyword(s):  
Specific Activity ◽  
Supported Catalysts ◽  
Sol Gel ◽  
Synthetic Route ◽  
Catalytic Systems ◽  
Hydrosilylation Reaction ◽  
Solid Catalysts ◽  
Sol Gel Process ◽  
Cis And Trans ◽  
Inorganic Matrices

The hydrosilylation reaction of phenylacetylene, generated on the surface of solid catalysts (such as Pt and Ru) supported on inorganic matrices such as MgO obtained by the sol-gel process, yields vinylsilanes as the main products. The products' distribution, specific activity, and turnover reactions were determined for the case of the hydrosilylation reaction of PhC = CH with R3SiH (R = Ph3, Ph2Me, and PhMe2). For Ph3SiH and Ph2MeSiH, the presence of β-trans and α isomers is observed. Addition of PhMe2SiH to phenylacetylene leads to the formation of β (cis and trans) and α isomers. These catalytic systems provide a new synthetic route to Si—C bond formation.Key words: Vinylsilanes, sol-gel catalysts, hydrosilylation and phenylacetylene.

Synthesis of Titania coated Alumina Particles by a Hybrid Sol-gel Method

2002 ◽  
Vol 740 ◽  
Author(s):  
A.D. Schmidt ◽  
S.B. Majumder ◽  
P.S. Dobal ◽  
R.S. Katiyar ◽  
D.C. Agrawal
Keyword(s):  
Anatase Phase ◽  
Sol Gel ◽  
Rutile Phase ◽  
Microscopy Imaging ◽  
Nano Crystalline ◽  
Heat Treated ◽  
Alumina Particles ◽  
Gel Technique ◽  
Titania Coatings ◽  
Titania Coating

ABSTRACTModifying their surface with a coating of another ceramic material can dramatically alter the properties of ceramic particles. In the present work we have demonstrated that the Al2O3 particles can be successfully coated by TiO2 using a novel sol-gel technique. The nature of these coatings was predicted on the basis of scanning electron microscopy imaging in conjunction with the micro-Raman scattering measurements. The surface morphology of these particles shows that either individual or group of sub-micron alumina particles are coated with the nano-crystalline titania particles. The thickness of the titania coating could be varied by changing the precursor sol concentration. Amorphous titania was converted to anatase phase at 400°C and upon further heating it started transforming to rutile phase, and both these phases coexisted in the coated particles that were heat treated up to 800°C. The mechanical strength of the titania coating was measured qualitatively by ultrasonicating the coated powders for longer duration to observe that titania coatings are strongly adhered with the alumina particles.

Bicontinuous nanodisc and nanospherical titania materials prepared by sol-gel process in reverse microemulsion

2012 ◽  
Vol 66 (3) ◽  
Author(s):  
Khaled Haouemi ◽  
Fathi Touati ◽  
Néji Gharbi
Keyword(s):  
Sol Gel ◽  
Textural Properties ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tio2 Particles ◽  
Sol Gel Process ◽  
Bet Method ◽  
Reverse Microemulsions ◽  
Different Shapes

AbstractTiO2 nanoparticles with different shapes and sizes were synthesised by the sol-gel route in Water/Brij78/Hexane reverse microemulsions. The aqueous cores of these microemulsions were used as nanoreactors to control sol-gel reactions. We studied the effect of water/surfactant mole ratio (W 0) on the morphology, and textural properties of the final products. The materials thus obtained were characterised by different techniques. Thermogravimetric and differential thermal analysis (TG-DTA) was used to study the thermal behaviour of the products and X-ray diffraction (XRD) to identify the crystalline phases. The morphological and textural properties of the products were determined by scattering electron microscopy (SEM) and the Brunauer-Emmett-Teller (BET) method, respectively. We also studied the influence of thermal treatment on the structure and size of the TiO2 particles. The effect of W 0 on the anatase-rutile phase transition temperature was investigated.

Growth of TiO2 Nanotube Arrays using Porous Anodic Alumina Templates

2013 ◽  
Vol 1601 ◽  
Author(s):  
A. Shoja ◽  
A. Nourmohammadi ◽  
M. H. Feiz
Keyword(s):  
Anatase Phase ◽  
Sol Gel ◽  
Rutile Phase ◽  
Nanotube Arrays ◽  
Nanoporous Alumina ◽  
Heat Treated ◽  
Semiconductor Behavior ◽  
Dc Electric Field ◽  
Nanoporous Alumina Templates ◽  
Anodic Alumina Templates

ABSTRACTThe aim of this research study is to produce high quality TiO2 nanotube arrays. It is shown that sol-gel electrophoresis is a suitable one to obtain vast-area TiO2 nanotube arrays when nanoporous alumina templates are used. To fabricate TiO2 nanotube arrays, alumina templates were produced via a two-step anodizing by a homemade anodizing cell using high purity phosphoric acid as the electrolyte with aluminum and platinum as electrodes. The semiconductor behavior of these templates can also be employed when producing conducting substrates for the grown TiO2 nanotubes. Stabilized titanium sol was prepared by modified hydrolysis of the titanium precursor using acetic acid. In order to produce TiO2 nanotube arrays, the template pores were filled with the precursor sol by applying a DC electric field. Then, the filled template was heat treated to crystallize the desired TiO2 phase. Scanning electron microscopy of TiO2 nanotube arrays showed that the nanotubes have been deposited in the channels of the nanoporous alumina template. X-ray diffraction data confirmed phase structure and composition of TiO2 nanotube arrays after heat treatment. To reach pure anatase phase, the samples were heated at 320°C and 400°C for two hours. To obtain pure rutile phase, the samples were heated at 320°C and 750°C for two hours.

Preparation of Nanosized TiO2 Synthesized by Sol-Gel Pathway Using Ionic Liquid as Assistant and its Photocatalytic Activities

2012 ◽  
Vol 535-537 ◽  
pp. 2240-2244
Author(s):  
Wei Wei ◽  
Chang Shun Yu ◽  
Shao Jun Wang ◽  
Qing Da An
Keyword(s):  
Ionic Liquid ◽  
Diffuse Reflectance ◽  
Sol Gel ◽  
Rutile Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Photocatalytic Activities ◽  
Average Size ◽  
Nanosized Tio2

Nanosized TiO2 particles were synthesized by sol-gel method using ionic liquid as assistant. The samples were characterized by UV-vis diffuse reflectance spectra, X-ray diffraction (XRD), transmission electron microscopy (TEM). It was shown that the phase detectable was mainly rutile phase with uniform sphericity and the average size was 10nm. Along with the rise of sintering temperature, grain diameter became bigger. The photocatalytic activities of nanosized TiO2 were evaluated by the reduction yield in the presence of CO2 and water. The result showed that TiO2 catalysts has efficient photocatalytic activities, of which made with [OMIM]BF4 displayed the highest photocatalytic active in the experiment.

Effect of Cores on Photoluminescence of Hybrid SiO2-Coated CdTe Quantum Dots

2020 ◽  
Vol 20 (9) ◽  
pp. 5478-5485
Author(s):  
Cong Xie ◽  
Yubin Zhao ◽  
Yuxiang Song ◽  
Yingjie Liu ◽  
Yaya Wang ◽  
...  
Keyword(s):  
Quantum Dots ◽  
High Stability ◽  
Sol Gel ◽  
Quantum Yields ◽  
Core Shell ◽  
Aqueous Synthesis ◽  
Pl Spectra ◽  
Cdte Qds ◽  
Sol Gel Process ◽  
20 Nm

Compared with conventional semiconductor quantum dots, hybrid SiO2 coated CdTe QDs exhibited high stability, long fluorescent lifetime, high photoluminescence quantum yields, and well biocompatibility. In this paper, CdTe QDs with tunable PL from green to red emitting were prepared by an aqueous synthesis. A sol–gel process resulted in CdTe QDs coated with a hybrid SiO2 shell contained CdS-like clusters to obtain red-shifted PL spectra, increased PL efficiency and high stability. The clusters were formed by the reaction of Cd2+ and S2− ions generated via the decomposition of thioglycolic acid. The clusters around CdTe cores created a core–shell structure which is very similar with traditional semiconductor core–shell QDs. After being coated with a hybrid SiO2 shell, the PL of green-emitting naked CdTe QDs was red-shifted largely (~30 nm) while the PL of yellowemitting CdTe QDs revealed a small red-shifted (~20 nm). Furthermore, The PL of red-emitting naked CdTe QDs was red-shifted much small (less than 10 nm). This phenomenon is ascribed to the change of band gap of CdTe cores with sizes. The red-shift of PL spectra is attributed to the CdS-like clusters around the core rather than the thickness of the hybrid SiO2 shell.

Sign in / Sign up

Export Citation Format

Share Document