Characterization and Photocatalytic Activity of La1.6Ln0.4Zr2O7 (Ln= La, Nd, Dy, Er) Nanocrystals by Stearic Acid Method

2010 ◽  
Vol 123-125 ◽  
pp. 631-634 ◽  
Author(s):  
Yu Ping Tong ◽  
Shun Bo Zhao ◽  
Feng Lan Li ◽  
Chang Yong Li

La1.6Ln0.4Zr2O7 (Ln= La, Nd, Dy, Er) nanocrystals were prepared by stearic acid combustion method. The samples were characterized by powder X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) nitrogen adsorption, transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The photocatalytic activity of La1.6Ln0.4Zr2O7 was evaluated by the photocatalytic degradation of methyl orange. The order of the photocatalytic activity was as following: La1.6Er0.4Zr2O7>La1.6Dy0.4Zr2O7> La1.6Nd0.4Zr2O7> La2Zr2O7. La1.6Dy0.4Zr2O7 showed that the best photocatalytic activity and the reason may be related to the big magnetic moment of Er3+. It may be considered largely to be caused by the partly occupied Ln4f levels. Since the solid samples have the same structure, the reason that La1.6Er0.4Zr2O7 shows the highest reactivity may be related to lowest Ln4f level of Er3+.

MRS Advances ◽  
2019 ◽  
Vol 4 (61-62) ◽  
pp. 3423-3431
Author(s):  
Daniela K. Calvo-Ramos ◽  
Marina Vega-González ◽  
José Santos-Cruz ◽  
Francisco Javier De Moure-Flores ◽  
Sandra A. Mayén-Hernández

ABSTRACTNanoparticles of titanium dioxide (TiO2), synthesized by the sonochemical technique, were mixed with different amounts of graphene oxide (GO), obtained by the improved method of Hummer, in order to modify their bandwidth. The TiO2/OG compounds were characterized using different techniques: X-ray Diffraction (XRD), transmission electron microscopy (TEM), Raman and UV-Vis-NIR spectroscopy. TiO2 bandgap decreased, with GO incorporation, from 3.2 to 2.72 eV when GO was present at 20 weigh percentage (TiO2/GO-20%). Photodegradation experiments of methylene blue (MB) were performed with the materials to verify their photocatalytic activity. At 40 minutes, the pure TiO2 degraded 48% of MB, whereas the compound TiO2/GO-20% degraded 88%, showing a good incorporation of both compounds and the improvement of TiO2 photocatalitic properties.


RSC Advances ◽  
2015 ◽  
Vol 5 (54) ◽  
pp. 43473-43479 ◽  
Author(s):  
Yanli Xu ◽  
Mengmeng Lv ◽  
Hanbiao Yang ◽  
Qi Chen ◽  
Xueting Liu ◽  
...  

The BiVO4/MIL-101 composite and pure materials were characterized by X-ray diffraction, transmission electron microscopy, thermogravimetric analysis, UV-vis diffuse reflectance absorption spectra and photoluminescence emission spectra.


2006 ◽  
Vol 60 (21-22) ◽  
pp. 2682-2685 ◽  
Author(s):  
Marcelo J.B. Souza ◽  
Antonio S. Araujo ◽  
Anne M.G. Pedrosa ◽  
Bojan A. Marinkovic ◽  
Paula M. Jardim ◽  
...  

TAPPI Journal ◽  
2012 ◽  
Vol 11 (5) ◽  
pp. 33-38 ◽  
Author(s):  
SEONGHYUK KO ◽  
PAUL D. FLEMING ◽  
MARGARET JOYCE ◽  
PNINA ARI-GUR

We investigated the effect of the crystalline phases of titanium dioxide nanopigment to optimize the optical properties and photocatalytic activity for synthesizing a photoactive paper. Six different ratios of anatase to rutile were prepared. Phase change and particle size were characterized using X-ray diffraction and transmission electron microscopy. Optical properties including opacity and brightness were tested. Photocatalytic activity was evaluated by measuring toluene decomposition, using gas chromatography. A specific ratio between two different crystallites of titanium dioxide showed relatively better optical and photoactive properties. The optimal anatase-to-rutile ratio was found to be 0.52:0.48.


2004 ◽  
Vol 49 (4) ◽  
pp. 177-181 ◽  
Author(s):  
C.Y. Yun ◽  
J. Moon ◽  
K. Chung ◽  
M. Kang ◽  
C.B. Shin ◽  
...  

Photocatalytically active nanocrystalline titania particles were prepared using a hydrothermal process, by controlling the particle size and crystallinity. The crystalline structures and morphologies of the particles were characterized by X-ray diffraction and transmission electron microscopy. The BET method was used to determine the surface area and verify the grain size. To estimate the photocatalytic activity of the synthesized particles, a dye photodegradation experiment was carried out and the activity of the particles was compared with that of conventional titania. The results show that synthesized nanocrystalline titania particles had a higher photocatalytic activity than that of conventional titania. These findings provide a basis for the preparation of more effective and useful materials for use in AOP applications.


2013 ◽  
Vol 651 ◽  
pp. 187-192 ◽  
Author(s):  
Gang Cheng Zhou ◽  
Quan Xin Zhu ◽  
Wan Qing Xiong ◽  
Jian Lei ◽  
Wen Xiang Ye ◽  
...  

ZnO/TiO2 nanocomposites were prepared by mixing of ultrasonic vibration and sintering at 500°C for 2 h initial nano-ZnO and nano-TiO2 which were synthesized by a microwave irradiation heating technique from an aqueous solution of Zn(Ac)2•2H2O, Ti(SO4)2, respectively. The samples were characterized by the techniques of X-ray diffraction (XRD) and transmission electron microscopy (TEM). And we have also carried on research to the photocatalytic activity of the as-prepared ZnO/TiO2 nanocomposites by photo-degrading methyl orange. The result indicates that the as-prepared sample is a good photocatalyst. When m (TiO2) /m (ZnO) ratio was equal to 4, the photocatalytic activity of the nanocomposites is best. The result shows that the degradation ratio of the methyl orange (2mg/L) has reached 93% within 80 min


2009 ◽  
Vol 620-622 ◽  
pp. 671-674
Author(s):  
Hui Hui Li ◽  
Yu Hua Wang

This paper aims at the investigation of photocatalytic properties of titanium dioxide coatings covering on the surfaces of long blue-emitting afterglow CaAl2O4:Eu2+, Nd3+ elaborated by a sol-gel method. Morphologies and microstructures of the coatings were observed mainly by transmission electron microscopy (TEM) and analyzed by X-ray diffraction (XRD). The photocatalytic behavior of the TiO2-base surfaces was evaluated by the degradation of methyl orange (MO) solution. It suggested that a layer of TiO2 film mounted on the phosphor particles successfully. Also, the TiO2 coatings had remained its photocatalytic role on the as-prepared sample even after the light source was removed. The inner long blue-emitting afterglow had released blue afterglow after removing light source and allowed for reactive TiO2 surfaces to be held for the removal of methyl orange.


2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
M. Th. Makhlouf ◽  
B. M. Abu-Zied ◽  
T. H. Mansoure

Combustion method has been used as a fast and facile method to prepare nanocrystalline Co3O4 spinel employing sucrose as a combustion fuel. The products were characterized by thermal analyses (TGA and DTA), X-ray diffraction technique (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and transmission electron microscopy (TEM) techniques. Experimental results revealed that the molar ratio of fuel/oxidizer (F/O) plays an important role in controlling the crystallite size of Co3O4 nanoparticles. Transmission electron microscopy indicated that the crystallite size of Co3O4 nanocrystals was in the range of 13–32 nm. X-ray diffraction confirmed the formation of CoO phase with spinel Co3O4. The effect of calcination temperature on crystallite size and morphology has been, also, discussed.


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