scholarly journals Upconversion Luminescence and Photodegradation Performances of Pr Doped Y2SiO5Nanomaterials

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Yi Yang ◽  
Cheng Liu ◽  
Ping Mao ◽  
Lian-Jun Wang
Keyword(s):  
Doping Concentration ◽  
Crystal Size ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Fine Crystal ◽  
X Ray ◽  
Photodegradation Rate ◽  
Infrared Spectrometer ◽  
Fluorescence Spectrometer ◽  
Degradation Time

Yttrium silicates Y2SiO5upconversion nanomaterials with different doping concentrations of praseodymium ion Pr are prepared by using a sol-gel method. X-ray diffractometer, SEM, Fourier transform infrared spectrometer, and fluorescence spectrometer have been employed to test the crystal structure and upconversion luminescence performances. The results indicate that samples calcined higher than 950°C present fine crystal structures, of which Si-O-Si band at 757–1048 cm−1splits into three fine peaks. The crystal size of the samples calcined at 950°C and 1000°C is 29.1 nm and 66.7 nm, respectively. The luminescence intensities of the samples are increasing at first and then decreasing, with the increasing of the doping concentrations of 0.47%, 0.77%, 0.96%, 2.95%, and 4.93%. Nanomaterial sample doped 0.96% Pr emits the highest upconversion luminescence intensity of 6.43 × 106 cps and shows the best photodegradation performance for nitrobenzene wastewater. It demonstrates that too much of Pr doping concentration would result in quenching of the fluorescence. Nevertheless, as the degradation time expands, sample doped 0.96% Pr shows much faster increasing of photodegradation rate than samples of other doping concentrations and reaches to a high photodegradation rate of 97.14% in 6 hours for 10 mg/L nitrobenzene wastewater.

scholarly journals Effect of Li(I) and TiO2on the Upconversion Luminance of Pr:Y2SiO5and Its Photodegradation on Nitrobenzene Wastewater

2015 ◽  
Vol 2015 ◽  
pp. 1-7 ◽  
Author(s):  
Yi Yang ◽  
Guang-Zhi Xia ◽  
Cheng Liu ◽  
Jin-Hua Zhang ◽  
Lian-Jun Wang
Keyword(s):  
Crystal Size ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Lithium Ion ◽  
Coating Film ◽  
High Luminance ◽  
Photodegradation Rate ◽  
Crystal Transition ◽  
Fluorescence Spectrometer

Based on the substrate of Pr:Y2SiO5upconversion nanomaterials, lithium ion Li(I) doped Pr:Y2SiO5and TiO2nanofilm coated Li,Pr:Y2SiO5composites were prepared by using a sol-gel method. X-ray diffractometer, SEM, and fluorescence spectrometer have been employed to test the crystal structure, microimages, and upconversion luminescence performances. The doping of Li(I) affects highly the crystal transition of Pr:Y2SiO5and X2-Y2SiO5phase was well formed by doping 8% Li(I). Furthermore, the doping of Li(I) also brings high luminance intensity of Pr:Y2SiO5and contributes to a maximum intensity of 9.76 × 106cps doped 8%. Too much of Li(I) doping would result in big crystal size and fluorescence quenching of Pr:Y2SiO5material. However, the coating of TiO2nanofilm is not helping in increasing the upconversion fluorescence of Li,Pr:Y2SiO5but is promoting the full use of the fluorescence. The luminescence intensities of TiO2/Li,Pr:Y2SiO5composites are getting down sharply with the coating amount since the luminescence emitted by Li,Pr:Y2SiO5is quickly adsorbed in situ by the TiO2coating film. With the optimum coating concentration of 1%, the TiO2/Li,Pr:Y2SiO5composite shows excellent photodegradation performances on nitrobenzene wastewater, though it shows a low luminescence intensity. For 5 mg/L nitrobenzene wastewater, the composite presents a photodegradation rate of 97.08% in 4 hours.

Preparation and Photocatalytic Properties of Rod-Shaped TiO2 Based on Salix Fiber

2014 ◽  
Vol 609-610 ◽  
pp. 250-254
Author(s):  
Ya Bin Li ◽  
Jin Tian Huang ◽  
Yan Fei Pan
Keyword(s):  
Photocatalytic Performance ◽  
Sol Gel ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Nanocomposite Structure ◽  
X Ray ◽  
Infrared Spectrometer ◽  
Ft Ir ◽  
Degradation Of Methyl Orange ◽  
Scanning Electron

In the paper, the TiO2nanomaterials adopted the microcrystalline cellulose as the template by the template method and sol-gel method was prepared. Through the infrared spectrometer (FT-IR), scanning electron microscope (SEM), X-ray diffraction (XRD), the surface morphology, composition and the type of the samples were characterized respectively. The influence of the macro morphology of TiO2photocatalytic performance to use the reaction of decolorization and degradation of methyl orange as model was analyzed. The results showed that TiO2which was produced by the template of sallix fiber was Rod-shaped and the average diameter size of nanocomposite structure was 20.592 nm, which can provide a new method of producing other morphology of TiO2.

Preparation, Characterization and UV Absorption of Phosphotungstic Acid Cerium

2014 ◽  
Vol 1061-1062 ◽  
pp. 328-332
Author(s):  
Hai Lian Yu ◽  
Zhen Hu
Keyword(s):  
Phosphotungstic Acid ◽  
Absorption Capacity ◽  
Uv Absorption ◽  
Precipitation Method ◽  
Gravimetric Analysis ◽  
X Ray ◽  
Good Thermal Stability ◽  
Infrared Spectrometer ◽  
The Fourier Transform ◽  
Fluorescence Spectrometer

Phosphotungstic acid cerium [CePW12O40] was prepared with phosphotungstic acid and hydrate cerium nitrate by precipitation method. The Fourier transform infrared spectrometer, X-ray diffractometer, X-ray fluorescence spectrometer and thermal gravimetric analysis were used to characterize product, The UV-VIS spectrophotometer was used to measure its absorption capacity. The results showed that the prepared product is CePW12O40, it has good crystal and good thermal stability, its purity reaches 99.55%, there is good UV absorption property between 200nm and 260nm..

Structure and Up-Conversion Luminescence Properties of Er3+-Yb3+Co-Doped TiO2 Nanocrystals Prepared by Sol-Gel Method

2009 ◽  
Vol 66 ◽  
pp. 167-170 ◽  
Author(s):  
Zhen Zhong Zhang ◽  
Ji Hong Zhang ◽  
Wei Zhou ◽  
Ming Xia Song ◽  
Wei Li ◽  
...  
Keyword(s):  
Titanium Tetrachloride ◽  
Upconversion Luminescence ◽  
Sol Gel ◽  
Green Emission ◽  
X Ray Diffraction ◽  
Red Emission ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Co Doped

Er3+/Yb3+ co-doped TiO2 nanocrystals were prepared by Sol-gel method in which titanium tetrachloride was adopted as the precursor. The structure, particle size, and optical properties of samples were characterized by X-ray diffraction(XRD), Field emission-Scanning Electron Microscopy(FE-SEM) and photoluminescence(PL) spectra. Er3+ concentration was fixed at 1.0mol%, and Yb3+ concentration was changed from 3 to 10mol%. Intense upconversion luminescence was observed when the samples were excited by 980nm laser. The dependence of upconversion luminescence on Yb3+ concentration was presented. The results show that the upconversion luminescence increases with the Yb3+ concentration and gets its peak at 5%. The ratio of red emission to green emission(R/G) was strikingly enhanced with the increase of Yb3+ concentration. Under the excitation of 980nm, the green emission in the range of 520-570nm (2H11/2, 4S3/2→4I15/2) and the red emission in the range of 640~690nm (4F9/2 →4I15/2) are both due to two photons process. The possible upconversion mechanism was discussed.

N-Doped Cu11O2 (VO4)6 Photocatalyst Prepared by Sol-Gel Method

2011 ◽  
Vol 393-395 ◽  
pp. 1287-1290
Author(s):  
Min Wang ◽  
Qiong Liu ◽  
Qi Xing
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Photodegradation Rate ◽  
Triclinic Phase ◽  
Synthesized Materials

The N-doped Cu11O2 (VO4)6 photocatalyst was prepared using the sol-gel method. Techniques of X-ray diffraction (XRD), scanning electron microscope (SEM) have been employed to characterize the as-synthesized materials. During liquid phase photocatalytic degradation of Methy lorange(MO) under the UV-light, the as-prepared N-doped Cu11O2 (VO4)6 exhibits higher activity than the pure Cu11O2 (VO4)6 without doped N. It found that the N-doped Cu11O2 (VO4)6 prepared with the molar ratio of citric acid to metal inons be 2:1, N/Cu molar ratio of 12%, pH=7 and calcinated under 500°C for 4 hours was pure triclinic phase. In this conditions, the sample had highest photocatalytic activity with the photodegradation rate was about 94.42% or so in 60min under 20W ultraviolet lamp.

scholarly journals Effects of Li+ Doping Concentration on Structure and Photoluminescence of the Y2O3: Ho3+/Yb3+ Up-conversion Film

2019 ◽  
pp. 1-8 ◽  
Author(s):  
Min Sun ◽  
Wenbo Hou ◽  
Juncheng Liu ◽  
Lifang Nie
Keyword(s):  
Doping Concentration ◽  
Crystal Size ◽  
Sol Gel ◽  
Emission Spectra ◽  
Luminescent Properties ◽  
Optical Transmittance ◽  
Li Doping ◽  
Maximum Value ◽  
Size Of Particles ◽  
Co Doped

The Li+ co-doped Y2O3: Ho3+/Yb3+ films were prepared with sol-gel method and spin-coating technique. The effects of Li+ on the structure and luminescent properties of the films were investigated. The results show the grain size increased first and then decreased with the increase of Li+ doping concentration. The crystal size of particles composing the film got the maximum value when Li+ concentration took 4 mol%. As Li+ doping concentration increased, the optical transmittance of the Y2O3: Ho3+/Yb3+ film improved at first then reduced and got the maximum at 3 mol%. Excited with a 980-nm laser, there were two green emissions in the up-conversion emission spectra, one centered at 535 nm, the other at 550 nm, which ascribed to the 5F4→5I8 and 5S2→5I8 transitions of Ho3+, respectively. The up-conversion luminescence intensity also increased firstly and then decreased with the Li+ doping concentration increase, and got the highest value at 2 mol%.

scholarly journals The Synthesis and Characterizations of CeY0.15Er0.05O2 Nanocrystal

2021 ◽  
Vol 22 (2) ◽  
pp. 341-344
Author(s):  
Handan Özlü Torun
Keyword(s):  
Crystal Size ◽  
Sintering Temperature ◽  
Sol Gel ◽  
Impedance Analysis ◽  
Fluorite Structure ◽  
X Ray Diffraction ◽  
X Ray ◽  
Organic Species ◽  
Unit Cell Size ◽  
Structure Properties

CeY0.15Er0.05O2 nanocrystal powders prepared via sol-gel method. Phases identification have been made X-ray diffraction, SEM-EDX, FTIR, thermal and impedance analysis. XRD data show that all powders were obtained with cubic fluorite structure. With the increase of sintering temperature, the unit cell size decreased and the crystal size increased. The particle size was found to be in the range of 150 to 270 nm. It was found that the nitrates and organic species seen in the FTIR results. It was observed that organic species disappeared at sintering temperatures selected according to thermal analysis results. Impedance measurements of the pelletized sample were made. Although the crystal structure properties were good, it was found that the conductivity values were low.

Comparative Study on the Structure and Properties of Japanese and Self-Made Precursors

2011 ◽  
Vol 317-319 ◽  
pp. 292-296
Author(s):  
Bao Hua Ji
Keyword(s):  
Comparative Study ◽  
Crystal Size ◽  
Cyano Group ◽  
Structure And Properties ◽  
X Ray Diffraction ◽  
Compact Structure ◽  
Cross Sectional ◽  
Xrd Pattern ◽  
X Ray ◽  
Infrared Spectrometer

In order to release the important information on the structural constitution of Japanese precursor, comparative study on structure and properties of Japanese and self-made precursors were carried out by X-ray Diffraction (XRD), infrared spectrometer (FTIR), element content analysis and the breaking tenacity. It was found that Japanese precursor contains cyano group (–CN) and may contain styrene sulfonic acid amine, while not containing the carboxyl and ester carbonyl, that is, not containing MA. The XRD pattern of Japanese precursor around 10° appears a new crystalline diffraction peak, and the crystal size becomes lower. The cross-sectional shapes of Japanese precursor are circle, with uniform and compact structure, thus its mechanical properties is superior.

Effect of the Ce-Doped TiO2 on the Photocatalysis Degradation of MB

2013 ◽  
Vol 320 ◽  
pp. 220-225 ◽  
Author(s):  
Xiao Ye Fu ◽  
Xiu Hong Liang
Keyword(s):  
Visible Light ◽  
Uv Light ◽  
Sol Gel ◽  
Crystal Form ◽  
X Ray Diffraction ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Crystal Transformation ◽  
Infrared Spectrometer

In this paper, we prepared a series of powders (pure TiO2 and Ce-doped TiO2) by sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), infrared spectrometer (IR) and UV spectrophotometer. The results indicated that the doped Ce influence the crystal structure of TiO2 and improve the temperature of crystal transformation. In the degradation of MB experiment, after 5 hours, the degradation efficiency of them (pure TiO2 , Ce-doped TiO2 and P25) under UV light is about 99.1%, while under visible light,Ce-doped TiO2 is about 60% higher than pure TiO2 and P25, up to 73%. This illustrates that the doped Ce increase the absorption to visible light and improve the photocatalytic efficiency.Key Words: TiO2, Ce-doped TiO2, photocatalyst, sol-gel method, crystal form

Growth of the Sol-Gel Based ZnO:Al Thin Films with High Doping Concentration

2012 ◽  
Vol 485 ◽  
pp. 144-148
Author(s):  
Jian Lin Chen ◽  
Yan Jie Ren ◽  
Jian Chen ◽  
Jian Jun He ◽  
Ding Chen
Keyword(s):  
Thin Films ◽  
Doping Concentration ◽  
Sol Gel ◽  
Zno Thin Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
High Doping Concentration ◽  
Doped Zno ◽  
Surface Morphologies

Preferentially oriented Al-doped ZnO thin films with doping concentration of 1, 2, 3, 5 and 10 mol% respectively were prepared on glass substrates via sol-gel route. The crystallinity of films was characterized by X-ray diffraction and the surface morphologies were observed by scanning electron microscopy. The results show that ZnO:Al films at low doping concentration (1, 2 mol%) grow into dense homogenous microstructure. However, as for high doping concentration (3, 5, 10 mol%), Al3+ precipitate in the form of amorphous Al2O3 and ZnO:Al films exhibit heterogeneous nucleation and exceptional growth of the big plate-like crystals at the interface of the amorphous Al2O3 and ZnO:Al matrix.

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