The Preparation of the Magnetically Separated Cu Doped TiO2 by Coating-Calcining Method

2011 ◽  
Vol 197-198 ◽  
pp. 857-860
Author(s):  
Han Yu Chen ◽  
Bao Shan Zhao ◽  
Zhao Hui Li

In this paper, a magnetic hollow fly ash microsphere(MHFM) was prepared by citrate sol-gel method and the Cu doped TiO2nanopowder were prepared by sol-gel process at which the novel magnetic Cu-doped TiO2photocatalyst (M-Cu/TiO2) was prepared by coating-calcining process. The crystal phase and morphology of M-Cu/TiO2were investigated by Scanning electron microscopy(SEM), X-ray diffraction(XRD), The photocatalytic activities of the prepared photocatalyst under different preparation conditions were evaluated by the degradation of methyl orange (MO). Results showed that these TiO2photocatalysts were highly efficient for the destruction of methylene orange in water. In addition, the multi-coating procedure made it possible to effectively control the physical properties of TiO2layer such as the coating thickness, amount of TiO2and photocatalytic activity. The floating catalyst made by this method could also be separated easily from the reaction system. And the multilayer film has higher photocatalytic activity than TiO2film under visible light irradiation.

2010 ◽  
Vol 97-101 ◽  
pp. 1611-1615 ◽  
Author(s):  
Qing Wang ◽  
Xin Li Li ◽  
Wei Nie ◽  
Yong Mei Xia ◽  
Jian Feng Dai

The ZnO/TiO2 composite films were deposited over glass using spin coating technique by sol-gel process. Single-walled carbon nanotubes (SWNTs) were used to modify the ZnO/TiO2 films successfully in this paper. The structure and composition of the ZnO/TiO2 composite and SWNTs doped ZnO/TiO2 composite were characterized by X-ray diffraction (XRD). The morphology of samples was characterized by scanning electron microscopy (SEM). The photocatalytic activity was investigated by photocatalytic degradation of aqueous methyl orange under ultraviolet (UV) radiation. The UV-vis absorption spectra of the ZnO/TiO2 films and SWNTs doped ZnO/TiO2 films in the wavelength region 200~800 nm were obtained. The results indicate that the SWNTs addition can decrease the grain size of ZnO/TiO2, which can enhance the photocatalytic activity. UV-vis absorption spectra of SWNTs-ZnO/TiO2 showed obvious blue shifts compared with ZnO/TiO2. The optimal amount of doping SWNTs is 1% according to this research. The enhanced mechanism of the SWNTs for the photocatalytic activity in ZnO/TiO2 films was analyzed in this article.


2018 ◽  
Vol 762 ◽  
pp. 408-412
Author(s):  
Raivis Eglītis ◽  
Gundars Mežinskis

In this work two different hydrosols were used to impregnate a commercially available cotton fabric with anatase nanoparticles to give it photocatalytic activity. To increase the activity, different pre-treatment methods were applied. The nanoparticle size was determined using dynamic light scattering and x-ray diffraction and the fabrics were examined using scanning electron microscopy. Photocatalytic activity was measured using the degradation of methyl-orange while irradiating the samples with UV light. The synthesis method allowed to produce anatase with an average particle size of 32 to 37 nm depending on the synthesis method used.


2011 ◽  
Vol 197-198 ◽  
pp. 926-930
Author(s):  
Min Wang ◽  
Qiong Liu ◽  
Chen Zhi Jiang

FeVO4photocatalysts were synthesized via a surfactant-assisted sol-gel method and characterized with X-ray diffraction (XRD), scanning electron microsoope (SEM)and specific surface area (BET). The photocatalytic activity was evaluated by photocatalytic degradation of methyl orange (MO) solution under visible light. The XRD patterns of no-surfactant-assisted, PEG-assisted, CTAB-assisted and SDS-assisted FeVO4, indicate that diffraction peaks can be well indexed as triclinc FeVO4. And the crystalline sizes of samples were evaluated as 113, 69, 66, 76 nm for FVO, FVO-PEG, FVO-CATB and FVO-SDS respectively.The addition of surfactant woul greatly affect the morphology of FeVO4photocatalysts, which can lead to different photocatalytic activities between them. In the experimental conditions used, the PEG-assisted FeVO4product had a much higher photocatalytic activity (the photodegradation rate was about 77% or so in 14h) than the other three products.


2006 ◽  
Vol 13 (04) ◽  
pp. 429-438 ◽  
Author(s):  
YONG LUAN ◽  
PINGFENG FU ◽  
XUEGANG DAI

In the present work, a combined route involving first doping of iron or neodymium ions via sol–gel method followed by acidification of the metal-doped TiO 2 particles for the improvement of the photocatalytic capability of TiO 2 was reported. The obtained metal-doped/acidified TiO 2 photocatalysts were thoroughly characterized by X-ray diffraction, Fourier transform infrared analysis, and photoluminescence emission spectra. At the same time, their photocatalytic activities were evaluated in simulant photodegradation of methylene blue (MB). The results based on these characterizations showed that not only a rutile layer formed on the surface of original TiO 2 particles after surface cladding, but also the doped Fe or Nd ion had a favorable effect on suppression of the electron–hole recombination in the titania under ultraviolet light irradiation. Furthermore, the photocatalytic activity of the material obtained by Fe doping and acidification was substantially improved in comparison to the untreated TiO 2. However, the sample prepared from Nd -doping and acidification of TiO 2 showed decreased capability relative to the untreated TiO 2 in degradation of MB under similar conditions. Finally, the reason why the photocatalytic activities of the obtained catalysts are sensitive to the metal-doping was discussed in details.


2013 ◽  
Vol 853 ◽  
pp. 73-78
Author(s):  
Yan Xi Deng ◽  
Chuan Chuan Liu ◽  
Guang Yang

Diatomite supported Cu-doped TiO2 photocatalysts were synthesized by sol-gel method and characterized by X-ray diffraction (XRD), SEM and UV-vis diffuses reflectance of spectroscopy (DRS). The photocatalytic activity was evaluated by photocatalytic degradation of methylene blue solution under visible light irradiation. The results show that TiO2/diatomite ratio had a great influene on their photocatalytic activities. All prepared Cu-TiO2/diatomite had a better photocatalytic activities in comparison with Cu-TiO2 and the Cu-TiO2(30)/diatomite had higher photocatalytic activity than others. The photocatalytic degradation of methylene blue is due to the breaking of the chormophoric group, rather than the simple decoloration.


2001 ◽  
Vol 16 (4) ◽  
pp. 907-909 ◽  
Author(s):  
Zi-Sheng Guan ◽  
Xin-Tong Zhang ◽  
Ying Ma ◽  
Ya-An Cao ◽  
Jian-Nian Yao

TiO2nanocrystals were prepared by a photo-assisted sol-gel process in which tetrabutoxide titanate was hydrolyzed in acidic medium under ultraviolet irradiation. X-ray diffraction and Raman spectra showed that the as-prepared TiO2particles without further annealing were well-crystallized anatase. Such TiO2particles were easily immobilized on dacron cloth and showed very high photocatalytic activity. In contrast, TiO2particles were ill crystallized and showed lower activity when no light was introduced under otherwise equal conditions.


2011 ◽  
Vol 230-232 ◽  
pp. 131-135
Author(s):  
Wen Jie Zhang ◽  
Yang Yu

The amounts of ethanol, HCl and H2O, and also calcination conditions during sol-gel process of preparing TiO2 photocatalyst were investigated. Methyl orange adsorption on TiO2 prepared using different sol compositions is not more than 4% by varying the amount of ethanol, HCl and H2O. The photocatalytic degradation is related to sol composition, and the optimal composition is composed of 10 ml ethanol, 1.0 ml H2O, and 0.1 ml HCl. Calcination temperature and time are also important in TiO2 preparation. The TiO2 particle prepared at 500 °C for 3 h has the optimal photocatalytic activity. In the irradiation time range up to 100 min, photocatalytic degradation rate constantly increases up to 94.2%.


2015 ◽  
Vol 713-715 ◽  
pp. 2785-2788
Author(s):  
Huan Yan Xu ◽  
Xue Li ◽  
Yan Li ◽  
Ping Li ◽  
Wei Chao Liu

In situ growth of TiO2 nanocrystals on the surface of schorl was realized via Sol-Gel method in this work. The obtained TiO2/schorl composite photocatalysts were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). An active dye, Methyl Orange (MO), was used to evaluate the photocatalytic activity of TiO2/schorl composite photocatalyst. The effect of sintering temperature and time on the photocatalytic activity of TiO2/schorl was emphasized in this work. XRD results indicated that TiO2 existed in the form of anatase only when the temperature was less than 550°C, and the sintering time was less than 2.5h. Higher sintering temperature and longer sintering time could impel the appearance of rutile phase. SEM observations revealed that the nanosized particles of TiO2 were well dispersed and immobilized on the surface of schorl. The optimum preparation conditions of TiO2/schorl composite with best photocatalytic activity were that sintering temperature was 550°C and sintering time was 2.5h.


2012 ◽  
Vol 217-219 ◽  
pp. 733-736
Author(s):  
Xiu Mei Han ◽  
Shu Ai Hao ◽  
Ying Ling Wang ◽  
Gui Fang Sun ◽  
Xi Wei Qi

Zn2SiO4:Eu3+, Dy3+ phosphors have been prepared through the sol-gel process. X-ray diffraction (XRD), thermogravimetric and ddifferential thermal analysis (TG-DTA), FT-IR spectra and photoluminescence spectra were used to characterize the resulting phosphors. The results of XRD indicated that the phosphors crystallized completely at 1000oC. In Zn2SiO4:Eu3+,Dy3+ phosphors, the Eu3+ and Dy3+ show their characteristic red(613nm, 5D0-7F2), blue (481nm, 4F9/2–6H15/2) and yellow (577nm, 4F9/2–6H13/2) emissions.


2012 ◽  
Vol 518-523 ◽  
pp. 775-779 ◽  
Author(s):  
Dong Dong Tan ◽  
De Fu Bi ◽  
Peng Hui Shi ◽  
Shi Hong Xu

The TiO2/NiFe2O4 (TN) composite nanoparticles with different mass ratios of NiFe2O4 to TiO2 were prepared via sol-gel method. X-ray diffraction was used to characterize the phase structure of TN. The results indicated that adulterating a smidgen of NiFe2O4 into the TiO2 (about 0.1%) can promote the phase transformation of TiO2, however, when the doping amount of NiFe2O4 surpasses 1%, the introduction of NiFe2O4 can inhibit the growth of TiO2 crystal grain and reduce the size of TiO2 crystal grain. The degradation experiment of methyl orange solution under UV illumination (253.7 nm) showed that the content of NiFe2O4 in the TN was higher, the photocatalytic activity of TN was worse, and the 0.1% TiO2/NiFe2O4 calcined at 400 °C presented the best photocatalytic activity.


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