scholarly journals Visible Light Excited Catalysis and Reusability Performances of TiO2@Pr:Y2SiO5 Upconversion Materials

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Yan Jiao ◽  
Yamiao Wang ◽  
Min Li ◽  
Ying Liu ◽  
Ping Mao ◽  
...  

To get high efficiency photodegradation on pollutants under visible light, Pr(III) doped Y2SiO5 upconversion materials and anatase TiO2 nanofilm coated Pr:Y2SiO5 composite have been prepared by using a sol-gel method. XRD and SEM test results indicated that TiO2 nanofilm was well coated on Pr:Y2SiO5 to form TiO2@Pr:Y2SiO5 composite particles with the sizes of 0.5–1.0 μm. To avoid secondary pollution resulting from incomplete recovery of catalyst particles, TiO2@Pr:Y2SiO5 was loaded on the glass fiber filters by using a dip-coating method. It is found that the catalyst particles were embedded into the carrier firmly, even after having been reused for 6 times. The luminescence intensities of TiO2@Pr:Y2SiO5 were getting down sharply with the coating contents of TiO2 increased, which was attributed to the adsorption of the luminescence by the TiO2 film in situ. As a result, TiO2@Pr:Y2SiO5 with 4% TiO2, which presented lowest luminescence intensity, showed the highest efficiency on the photodegradation of nitrobenzene wastewater. The catalysts loaded on glass fiber filters showed excellent reusability on the photodegradation of nitrobenzene and presented a photodegradation rate of 95% at the first time and up to 75.9% even after 6 times of reusing by the treatment time of 12 h.

2015 ◽  
Vol 1131 ◽  
pp. 237-241 ◽  
Author(s):  
Akkarat Wongkaew ◽  
Chanida Soontornkallapaki ◽  
Naritsara Amhae ◽  
Wichet Lamai

This work aims to study the effect of ZnO containing in TiO2/SiO2 film on the superhydrophilic property after exposed to different types of light. The metal solutions were prepared by sol-gel technique and the film was deposited on glass slides by dip coating method. The parameter studied was the amount of ZnO in the TiO2/SiO2 film. The contents of ZnO were 5-20% weight (increased by 5%). The amount of TiO2 was constant at 30% weight. The obtained films were analyzed for their roughness. The results indicated that film roughness changed according to the ZnO contents. With 5%ZnO in the thin film, the roughness was 0.726 nm while 20%ZnO obtained the roughness of 2.128 nm. UV-Vis spectrophotometer was used for measuring of transmittance of films. At wavelength of 550 nm, the transmittances of each film were greater than 90%. Band gap energy of each film was calculated from the transmittance data. It was found that the average band gap energy of the films was 2.47 eV. Then, the films contained various amount of ZnO were grouped into 2 sets. The first set was exposed to visible light while the other set was exposed to UV. The duration of exposure was 5 hr. Both sets of films after exposed to any light were kept in a black box controlled relative humidity of 85%. Each film was measured contact angle every day. It was found that the 30%TiO2/5%Zn/SiO2 film exposed to visible light showed the best superhydrophilic property. The contact angle was about 0-5° within 3 days. This may due to the reduction of band gap energy in the presence of ZnO in TiO2/SiO2 films to 2.41 eV and the roughness of the film.


2005 ◽  
Vol 486-487 ◽  
pp. 570-573
Author(s):  
Yo Seung Song ◽  
Deuk Yong Lee ◽  
Se Jong Lee ◽  
Bae Yeon Kim ◽  
Shin Nam Hong

SrZrO3 resistive oxides on Ag sheathed Bi(2223) tapes were prepared by the sol-gel and dip-coating method to investigate the effect of PVP content and thermal stage on microstructure of the films. Although film thickness rose with the addition of PVP, the amount of PVP was not effective to reduction in the crack density of the films. However, longer drying time at low temperature and shorter heat treatment time at 500oC were effective for controlling the microcracks of the SrZrO3 films, indicating that the microcracking of the films was governed primarily by the thermal stage.


2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Akira Nishimura ◽  
Go Mitsui ◽  
Masafumi Hirota ◽  
Eric Hu

A Cr-doped film was prepared by sol-gel and dip-coating method and used as the photocatalyst for reforming under the visible light. The ratio of amount of Cr added to amount of Ti in sol solution (R) varied from 0 to 100 wt%. The total layer number of Cr-doped film (N) coated was up to 7. The reforming performance with the Cr-doped film was evaluated by illuminating under a Xe lamp with or without ultraviolet (UV) light. The concentration of CO which was a product from reforming was maximized for  wt% whenNequals to 1. The visible light responsibility was also maximized for  wt%. The amount of Cr within film coated on copper disc was increased with the increase inRup to 70 wt% and started to decrease whenRis over 70 wt%. The reforming performance of film with one layer Cr-doped was found better than that of film with multi Cr-doped layers under illuminating of UV light. Under the visible light, the performance was maximized at  wt% and with one layer Cr-doped.


2000 ◽  
Vol 628 ◽  
Author(s):  
Kazuki Nakanishi ◽  
Souichi Kumon ◽  
Kazuyuki Hirao ◽  
Hiroshi Jinnai

ABSTRACTMacroporous silicate thick films were prepared by a sol-gel dip-coating method accompanied by the phase separation using methyl-trimethoxysilane (MTMS), nitric acid and dimethylformamide (DMF) as starting components. The morphology of the film varied to a large extent depending on the time elapsed after the hydrolysis until the dipping of the coating solution. On a glass substrate, the films prepared by early dipping had inhomogeneous submicrometer-sized pores on the surface of the film. At increased reaction times, relatively narrow sized isolated macropores were observed and their size gradually decreased with the increase of reaction time. On a polyester substrate, in contrast, micrometer-sized isolated spherical gel domains were homogeneously deposited by earlier dippings. With an increase of reaction time, the volume fraction of the gel phase increased, then the morphology of the coating transformed into co-continuous gel domains and macropores, and finally inverted into the continuous gel domains with isolated macropores. The overall morphological variation with the reaction time was explained in terms of the phase separation and the structure freezing by the forced gelation, both of which were induced by the evaporation of methanol during the dipping operation.


2006 ◽  
Vol 317-318 ◽  
pp. 807-810 ◽  
Author(s):  
Chang Yeoul Kim ◽  
Jin Wook Choi ◽  
Tae Yeoung Lim ◽  
Duck Kyun Choi

Electrochromic WO3 thin film was prepared by using tungsten metal solution in hydrogen peroxide as a starting solution and by sol-gel dip coating method. XRD pattern showed that tungsten oxide crystal phase formed at 400. In the view of electrochemical property, WO3 thin film which was heat-treated at 300 and was amorphous had better than that of the crystalline phase.


2017 ◽  
Vol 4 (9) ◽  
pp. 096403 ◽  
Author(s):  
Zohra N Kayani ◽  
Marya Siddiq ◽  
Saira Riaz ◽  
Shahzad Naseem

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
V. L. Chandraboss ◽  
B. Karthikeyan ◽  
J. Kamalakkannan ◽  
S. Prabha ◽  
S. Senthilvelan

The TiO2/SiO2 and ZnO/SiO2 composite films were prepared by sol-gel dip coating method. The surface morphology and crystal structure of thin films were characterized by means of scanning electron microscopy (SEM) with elementary dispersive X-ray analysis (EDX) and X-ray diffractometer (XRD). Optical properties of films have been investigated using ultraviolet and visible spectroscopy (UV-visible spectroscopy). The photocatalytic activity was established by testing the degradation and decolorization of methyl green (MG) from aqueous solution with artificial UV-light.


2014 ◽  
Vol 699 ◽  
pp. 9-14
Author(s):  
Zulkifli Mohd Rosli ◽  
Nur Hamizah Ahmad Rusli ◽  
Jariah Mohamad Juoi ◽  
Mazidah Zainudi

This research aims to determine the effect of ceramic substrates surface roughness on the deposition of silver-titania (AgTiO2) coating. The ceramic substrates were prepared from three batch mixture of waste glass namely transparent glass (99 wt. %): carbon black (1 wt. %), green glass (85 wt. %): ball clay (15 wt. %) and transparent glass (85 wt. %): ball clay (15 wt. %) deposited with AgTiO2 using sol gel dip coating method. Ti and Ag phases have been identified via glancing angle X-Ray diffraction analysis (GAXRD). The thickness and morphology of coatings were characterized using Scanning Electron Microscopy (SEM). Analyses conducted have confirmed that AgTiO2 coating layers have been successfully deposited into various types of selected ceramic substrates. Microstructure analysis shows that coatings deposited on ceramic substrate with a moderate surface roughness of 2.13 (green glass: ball clay) produced the most homogeneous surface and uniform thickness.


2014 ◽  
Vol 25 (10) ◽  
pp. 4339-4347 ◽  
Author(s):  
K. S. Venkatesh ◽  
K. Vijayalakshmi ◽  
K. Karthick ◽  
S. R. Krishnamoorthi ◽  
N. S. Palani ◽  
...  

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