Indium-Sensitized UV Photocatalysts Made from Alkali Titanate Microfibers

2009 ◽  
Vol 620-622 ◽  
pp. 651-654
Author(s):  
Leticia M. Torres-Martínez ◽  
Cecilia Sánchez-Trinidad ◽  
Vicente Rodríguez-González ◽  
Ricardo Gómez
Keyword(s):  
Heat Treatment ◽  
Annealing Time ◽  
Uv Light ◽  
Sol Gel ◽  
Dichlorophenoxyacetic Acid ◽  
Sem Images ◽  
Uv Light Irradiation ◽  
Heat Treated ◽  
Munk Function ◽  
Sol Gel Process

Indium-alkali microfibers doped ceramic were prepared by the sol-gel process. The gels preparation samples, were heat treated at 700°C for different length of time. The products were characterized by means of XRD, SEM-EDS and UV–Vis-DRS. The XRD showed the formation of the Na2Ti6O13 phase whose crystallinity depends on the annealing time. The band gap calculated from the UV–Vis Kubelka-Munk function shows very similar values (3.53-3.55 eV). The SEM images of the indium-alkali titanates show microfiber clumps morphologies of about 5 µm, and the EDS spectra show that In2O3 is on the Na2Ti6O13 surface. The results of the evaluation of the In-Na2Ti6O13 semiconductors in the 2, 4-dichlorophenoxyacetic acid (2, 4-D) photodecomposition under UV light irradiation, show that the photoactivity depends on the time of heat treatment of the samples.

Load TiO2 or TiO2-N on the Porous Carbon

2012 ◽  
Vol 512-515 ◽  
pp. 1686-1689
Author(s):  
Jie Chen ◽  
Le Fu Mei ◽  
Li Bing Liao
Keyword(s):  
Heat Treatment ◽  
Porous Carbon ◽  
Heat Treatment Temperature ◽  
Treatment Time ◽  
Sol Gel ◽  
Treatment Temperature ◽  
Heat Treatment Time ◽  
Sem Images ◽  
Soaking Time ◽  
Sol Gel Process

In this paper, porous carbon has been used to carry TiO2 and TiO2-N by a sol-gel process. The effect of soaking time, heat treatment temperature, and heat treatment time on the carrying efficiency have been studied. XRD experiments indicated that TiO2 and TiO2-N crystallized in anatase and rutile with the ratio of 3∶2. SEM images showed that island-like TiO2 and TiO2-N particles with diameters in the range of 1-5um, the biggest size is about 10um, were evenly coated on the surface of the porous carbon.

Photodegradation of Reactive Red 141 and Reactive Yellow 105 Dyes Using Prepared TiO2 Nanoparticles

2014 ◽  
Vol 807 ◽  
pp. 65-79 ◽  
Author(s):  
Augustine Amalraj ◽  
P. Anitha Pius
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Operational Parameters ◽  
X Ray Diffraction ◽  
Pseudo First Order Reaction ◽  
Illumination Time ◽  
X Ray ◽  
Uv Light Irradiation ◽  
Sol Gel Process ◽  
Dye Solutions

The photodegradation of Reactive Red 141 (RR-141) and Reactive Yellow 105 (RY-105) dyes using TiO2 nanoparticles was investigated under UV light irradiation. TiO2 was prepared by sol-gel process and characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) with Energy Dispersive X-ray analysis (EDAX) and FTIR. The effects of operational parameters such as illumination time, catalyst dose, initial concentration and pH of dye solutions on photodegradation by TiO2 have been analyzed. The degradation of the selected dyes followed pseudo-first order reaction according to the Langmuir-Hinshelwood kinetic model.

Preparation and characterization of GeS2

1996 ◽  
Vol 11 (2) ◽  
pp. 363-372 ◽  
Author(s):  
Vesna Stanić ◽  
Alain C. Pierre ◽  
Thomas H. Etsell ◽  
Randy J. Mikula
Keyword(s):  
Heat Treatment ◽  
Hydrogen Sulfide ◽  
Water Contamination ◽  
Sol Gel ◽  
Heat Treated ◽  
Sol Gel Process

Synthesis of GeS2 via a sol-gel process using germanium ethoxide and hydrogen sulfide in toluene resulted in a gel aggregate with an apparent Ge/S ratio 1:1.8. Special precautions were necessary to protect the reaction mixture from water contamination which produced GeO2. Results indicated that the main source of water was the hydrogen sulfide gas. Heat treatment of the produced GeSx gel yielded a product with Ge/S ratio 1:2.3. The sol-gel prepared materials and their heat-treated products were characterized by various methods.

Development of Carbon Nanostructures in an Intermediate Prepared from Sol-Gel Process

2007 ◽  
Vol 124-126 ◽  
pp. 775-778
Author(s):  
Kyu Suk Han ◽  
Tae Gyung Ko
Keyword(s):  
Heat Treatment ◽  
Carbon Nanotube ◽  
Carbon Nanostructures ◽  
Sol Gel ◽  
Carbon Nanostructure ◽  
Zirconium Alkoxide ◽  
Heat Treated ◽  
Multi Walled Carbon Nanotube ◽  
Sol Gel Process ◽  
Raman Study

We report the observation of the carbon nanostructures simply obtained from the sol-gel process using zirconium alkoxide with subsequent heat-treatment. A Raman study showed that the well-defined D and G active modes in multi-walled carbon nanotube similarly appeared in the sample prepared at 350 and 400 . Those disappeared when the sample was heat-treated above 450 , at which its phase fully transformed to zirconia. We observed through HRTEM that either sphere or tube-like carbon nanostructure appeared dispersedly or in a cluster among the oxide aggregates at 350 and 400 . Our study demonstrated that both of the two carbon nanostructures occurred in an intermediate related to carbonization, which may exist during the heat-treatment even in air

scholarly journals Upconversion and infrared emission of Er3+/Yb3+ co-doped SiO2-Gd2O3 obtained by sol-gel process

2015 ◽  
Vol 9 (1) ◽  
pp. 23-31 ◽  
Author(s):  
Leonardo Rocha ◽  
Sidney Ribeiro ◽  
Arnaldo Pereira ◽  
Marco Schiavon ◽  
Jefferson Ferrari
Keyword(s):  
Heat Treatment ◽  
Heat Treatment Temperature ◽  
Sol Gel ◽  
Infrared Region ◽  
Infrared Emission ◽  
Treatment Temperature ◽  
Cubic Phase ◽  
Heat Treated ◽  
Sol Gel Process ◽  
Co Doped

This work reports on the preparation of materials based on Yb3+/Er3+ co-doped SiO2-Gd2O3 via sol-gel process. The 0.4mol%of Er3+ ions was fixed and the amount of Yb3+ ions changed as 1.8, 5 and 9mol%in order to evaluate the photoluminescence properties as a function of the Yb3+ ions concentration. The prepared xerogels were heat-treated at 900, 1000 and 1100?C for 8 h. X-ray diffraction analyses of the heat-treated materials confirmed the formation of the Gd2O3 cubic phase embedded in the SiO2 host, demonstrating the effective incorporation of RE3+ ions in the structure. The Scherrer?s equation verified that the sizes of Gd2O3 nanocrystallite are between 31 and 69 nm and directly dependent on the heat-treatment temperature. Under excitation at 980 nm all materials showed upconversion phenomena, and the intensities of the emissions in the green and red regions showed to be directly dependent on power pump of laser, quantity of Yb3+ ions and heat-treatment temperature. The materials also showed emission in the infrared region with the maximum around 1530 nm, assigned to the transition of 4I13/2 ? 4I15/2 of the Er3+ ions, region known as technological C-telecom band used in optical amplification.

Photochromic Properties of WO3 Thin films

2008 ◽  
Vol 368-372 ◽  
pp. 336-338
Author(s):  
Xin Min Wang ◽  
Bo Liu ◽  
Hong Hua Cai ◽  
Zhong Kuang Luo ◽  
Xiang Zhong Ren ◽  
...  
Keyword(s):  
Thin Films ◽  
Uv Light ◽  
Sol Gel ◽  
Dip Coating ◽  
Light Transmittance ◽  
Photochromic Properties ◽  
Heat Treated ◽  
Sol Gel Process ◽  
Different Temperatures ◽  
Dip Coating Technique

WO3 sol was prepared through the sol-gel process. Ethanol, acetone and SiO2 sol were added to the WO3 sol. The WO3 thin films on glass substrate were obtained with the hybrid sol by the dip-coating technique, and then were heat-treated at different temperatures for a certain time. X-ray diffractometer and scanning electron microscope were used to characterize the crystal structure and surface morphology of these coatings. Visible light transmittance changes of the thin films irradiated under UV light were measured with UV spectrometer. The experimental results demonstrated that photochromic effect, hardness and uniformity of thin films were improved when the thin films are obtained with the hybrid sol.

Effective of SiO2 Addition on the Self-Cleaning and Photocatalytic Properties of TiO2 Films by Sol-Gel Process

2009 ◽  
Vol 620-622 ◽  
pp. 679-682 ◽  
Author(s):  
Dae Yong Shin ◽  
Kyung Nam Kim
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Sol Gel ◽  
Light Irradiation ◽  
Photocatalytic Properties ◽  
Water Contact ◽  
Sio2 Films ◽  
Uv Light Irradiation ◽  
Sol Gel Process ◽  
Self Cleaning

Thin films of various composition in the system of TiO2•SiO2 have been fabricated by the sol-gel process using Si(OC2H5) and Ti(OC3H7i)4 as precursors. TiO2•SiO2 films were formed on the glass substrate by spin-coating technique and heated at 500°C for 1 h. The relationship between hydrophilicity, photocatalytic properties and self-cleaning property with SiO2 addition and UV light irradiation were investigated. Photocatalytic activity of TiO2•SiO2 films showed decomposition of ~97% of acetaldehyde in 2 h and a water contact angle of ~10°. TiO2•SiO2 films can have more hydrophilic activity and less photocatalytic activity by increasing of SiO2 addition. XPS measurements revealed that the amount of organic compounds adsorbed on the films decreased with the UV light irradiation and SiO2 addition, because of the increased of both OH group contents in films and decomposed organic contaminants of the films surface.

scholarly journals Nanostructured LiFe5O8 by a Biogenic Method for Applications from Electronics to Medicine

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 193
Author(s):  
Silvia Soreto Teixeira ◽  
Manuel P. F. Graça ◽  
José Lucas ◽  
Manuel Almeida Valente ◽  
Paula I. P. Soares ◽  
...  
Keyword(s):  
Spinel Ferrite ◽  
Sol Gel ◽  
Reaction Medium ◽  
Magnetic Hyperthermia ◽  
Magnetic Characteristics ◽  
Secondary Phases ◽  
Heat Treated ◽  
Structure Morphology ◽  
Sol Gel Process ◽  
Crystallite Sizes

The physical properties of the cubic and ferrimagnetic spinel ferrite LiFe5O8 has made it an attractive material for electronic and medical applications. In this work, LiFe5O8 nanosized crystallites were synthesized by a novel and eco-friendly sol-gel process, by using powder coconut water as a mediated reaction medium. The dried powders were heat-treated (HT) at temperatures between 400 and 1000 °C, and their structure, morphology, electrical and magnetic characteristics, cytotoxicity, and magnetic hyperthermia assays were performed. The heat treatment of the LiFe5O8 powder tunes the crystallite sizes between 50 nm and 200 nm. When increasing the temperature of the HT, secondary phases start to form. The dielectric analysis revealed, at 300 K and 10 kHz, an increase of ε′ (≈10 up to ≈14) with a tanδ almost constant (≈0.3) with the increase of the HT temperature. The cytotoxicity results reveal, for concentrations below 2.5 mg/mL, that all samples have a non-cytotoxicity property. The sample heat-treated at 1000 °C, which revealed hysteresis and magnetic saturation of 73 emu g−1 at 300 K, showed a heating profile adequate for magnetic hyperthermia applications, showing the potential for biomedical applications.

scholarly journals TiO2-Powdered Activated Carbon (TiO2/PAC) for Removal and Photocatalytic Properties of 2-Methylisoborneol (2-MIB) in Water

Water ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 1622
Author(s):  
Xiao-Pin Guo ◽  
Peng Zang ◽  
Yong-Mei Li ◽  
Dong-Su Bi
Keyword(s):  
Activated Carbon ◽  
Natural Organic Matter ◽  
Uv Light ◽  
Sol Gel ◽  
Light Irradiation ◽  
Nano Tio2 ◽  
Uv Light Irradiation ◽  
Adsorption Capacities ◽  
Taste And Odor ◽  
Composite Photocatalysts

2-methylisoborneol (2-MIB) is a common taste and odor compound caused by off-flavor secondary metabolites, which represents one of the greatest challenges for drinking water utilities worldwide. A TiO2-coated activated carbon (TiO2/PAC) has been synthesized using the sol-gel method. A new TiO2/PAC photocatalyst has been successfully employed in photodegradation of 2-MIB under UV light irradiation. In addition, the combined results of XRD, SEM-EDX, FTIR and UV-Vis suggested that the nano-TiO2 had been successfully loaded on the surface of PAC. Experimental results of 2-MIB removal indicated that the adsorption capacities of PAC for 2-MIB were higher than that of TiO2/PAC. However, in the natural organic matter (NOM) bearing water, the removal efficiency of 2-MIB by TiO2/PAC and PAC were 97.8% and 65.4%, respectively, under UV light irradiation. Moreover, it was shown that the presence of NOMs had a distinct effect on the removal of MIB by TiO2/PAC and PAC. In addition, a simplified equivalent background compound (SEBC) model could not only be used to describe the competitive adsorption of MIB and NOM, but also represent the photocatalytic process. In comparison to other related studies, there are a few novel composite photocatalysts that could efficiently and rapidly remove MIB by the combination of adsorption and photocatalysis.

Preparation of Macroprous C12A7 Mayenite Monoliths via a Sol-Gel Process with Nitrates as Precursors

2018 ◽  
Vol 768 ◽  
pp. 211-217 ◽  
Author(s):  
Rui Wang ◽  
Yu Kun Sun ◽  
Bao Jia Qi Jiang ◽  
Hui Yang ◽  
Xing Zhong Guo
Keyword(s):  
Heat Treatment ◽  
Phase Separation ◽  
Binary System ◽  
Propylene Oxide ◽  
Crystalline Phase ◽  
Sol Gel ◽  
Single Crystalline ◽  
Sol Gel Process

Macroporous Ca12Al14O33(C12A7) mayenite monoliths have been successfully prepared via a sol-gel process in the presence of propylene oxide (PO) and poly (ethyleneoxide) (PEO). Gelation of CaO-Al2O3binary system with nitrates salts as additional precursors is accelerated by PO as an acid scavenger, while PEO works as a phase separation inducer to mediate the phase separation of the system. Appropriate PO and PEO amounts allow the formation of monolithic xerogel with interconnected macropores and co-continuous skeletons. The resultant dried gels are amorphous and the single crystalline phase Ca12Al14O33mayenite forms after heat-treatment at 1100 °C in air, while the macrostructure is preserved with a porosity as high as 78% and smoother and denser skeletons.

Sign in / Sign up

Export Citation Format

Share Document