Stabilization of tetragonal phase of nanostructured Fex/ZrO2 system (0 ≤ x ≤ 25) prepared by modified sol-gel method

2022 ◽  
Author(s):  
Abdelaziz Abu El-fadl ◽  
Amna Eltokhey ◽  
A. A. Abu-Sehly ◽  
Amina A. Abozeed

Abstract In the present study, Fex/ZrO2 (0 ≤ x ≤ 25) nanoparticles were synthesized by a facile modified Sol-Gel method. Stabilization of the tetragonal phase of ZrO2 is studied as a function of both the Fe incorporation ratios and thermal treatment. The Fe incorporation ratios are tested up to the extreme just before FeO and Fe2O3 phases are formed separately. The prepared Fex/ZrO2 nanoparticles XRD analysis depicts the formation of zirconium oxide at different Fe ratios in the nanoscale with an excellent degree of crystallinity in the tetragonal phase. The effect of thermal treatment on stabilizing the tetragonal phase of Fex/ZrO2 nanoparticles is extensively studied. The phase transition to the monoclinic phase is determined as function of Fe incorporation ratios and annealing temperatures. The optical absorbance spectra showed that the optical band gap decreased with increasing Fe ratios without the formation of doping bands which confirms the formation of Fex/ZrO2 single matrix.

2009 ◽  
Vol 2009 ◽  
pp. 1-8 ◽  
Author(s):  
Nor Hafizah ◽  
Iis Sopyan

NanosizedTiO2powder was synthesized via sol-gel method using titanium tetraisopoxide (TPT) as the precursor. Mol ratios of water to TPT were varied from 1 (Powder A), 2 (Powder B), 3 (Powder C), and 4 (Powder D) to evaluate effect of hydrolysis degree. TG/DTA curves showed that amorphous phase turned to anatase crystal structure at ca. 415, 337, 310, and339∘C for Powders A, B, C, and D, respectively. XRD analysis showed that all the synthesizedTiO2powders were 100% in anatase form with Powders B and C showing considerably higher crystallinities. The powders obtained at lower water to TPT mol ratios were spherical in shape and they became bar-like shapes higher mol ratios. The lower hydrolysis degree led to higher surface area of the Powder A (24.8 m2/g) compared to Powder B (14.6 m2/g). From phenol photocatalytic measurement, Powder B was the most efficient attributed to its higher crystallinity.


2020 ◽  
Vol 1000 ◽  
pp. 227-232
Author(s):  
Nurhayati Indah Ciptasari ◽  
Adri Nora ◽  
Lutviasari Nuraini ◽  
Lusiana ◽  
Nono Darsono ◽  
...  

Zirconia (ZrO2) powders doped with cobalt were prepared by sol-gel method using inorganic salt of zirconium (IV) chloride (ZrCl4) as precursor. The amount of cobalt was varied in the range of 4–16% weight percent to study the effect to structural properties. X-ray diffraction (XRD) analysis suggested the resulting phases were zirconium oxide (Baddeleyite) with monoclinic crystal system along with cobalt oxide as secondary phase. The increasing cobalt content caused the XRD peaks to shift into lower angle due to substitution of Zr atom to smaller Co atom in crystal lattice. Scanning electron microscope (SEM) images showed the samples with higher Co content had smoother surface. Generally, the microstructures of Co doped zirconia powders consisted of large agglomerates with small particles on the surface.


2009 ◽  
Vol 206 (9) ◽  
pp. 2139-2142 ◽  
Author(s):  
Takashi Ehara ◽  
Takafumi Otsuki ◽  
Junya Abe ◽  
Takaaki Ueno ◽  
Masahiro Ito ◽  
...  

2009 ◽  
Vol 6 ◽  
pp. 35-41
Author(s):  
Denis A. Ivanov-Pavlov ◽  
Vladimir G. Konakov ◽  
Elena N. Solovieva ◽  
Viktor M. Ushakov ◽  
Natalia V. Borisova

Powder precursors of the Al2O3-ZrO2 system were synthesized by the sol-gel method. Dispersity of the powders depended on synthesis and drying conditions. Differential Scanning Calorimetry, X-Ray diffraction, and method of adsorption–desorption isotherms were used to characterize the interrelations between particle size and phase transition in the Al2O3-ZrO2 system. It was revealed that azeotropic drying under overpressure is quite effective for obtaining well-dispersed powder precursors synthesized by the sol-gel method. In contrast to bulk materials, tetragonal, cubic, and monoclinic phases were found to exist in a wider temperature-composition range. It was shown that the existing phase symmetry in the well-dispersed powders correlates with the crystallite size.


2021 ◽  
pp. 61-73
Author(s):  
Yu.E. Lebedeva ◽  
◽  
N.E. Shchegoleva ◽  
V.A. Voronov ◽  
St.S. Solntcev ◽  
...  

The rheological properties, processes of structure and phase formation of the Al2O3–ZrO2 system compositions obtained by the sol-gel method have been investigated. The temperature range of crystallization of the compositions is 900–1100 °C. With an increase in the concentration of zirconium dioxide in the system, the temperature of the transition from the tetragonal to the monoclinic phase decreases. The effect of the ratio of the components in the initial solutions and the temperature regime of heat treatment of gels on the physicochemical properties of nanopowders and sintered materials has been studied. Ceramic materials of eutectic composition give the highest density and lower values of porosity and water absorption.


2011 ◽  
Vol 393-395 ◽  
pp. 1579-1582
Author(s):  
Yun Lan Xu ◽  
Jin Ping Jia

TiO2/Ti electrode, photoelectrocatalysis (PEC), rotating disk reactor, dye. Abstract: In this work, TiO2/Ti electrode was prepared by sol-gel method and its character was investigated by field emission scanning electron microscope (FESEM), X-ray reflection diffraction (XRD) spectra, UV-Vis diffuse reflection absorption spectra and photoelectro-response analysis. FESEM and XRD analysis demonstrates the TiO2 particles were uniform, about 50 nm and almost anatase, UV-Vis diffuse reflection analysis demonstrates the absoption fringe of TiO2 was 400 nm, and photoelectro-response analysis demonstrates the photoelectro-response capability of the photocatalyst was evident and decreased with the dye solution concenstrate increased. The results of stability and reproducibility of TiO2/Ti electrode demonstrates repetition of both multi-runs of mono-electrode and mono-run of multi-electrodes was excellent, which indicates TiO2/Ti electrode prepared by sol-gel method can degrade dye wastewater high-effectively and stably.


Catalysts ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 1449
Author(s):  
Zhuoying Jiang ◽  
Sameera Wickramasinghe ◽  
Yu Hsin Tsai ◽  
Anna Cristina S. Samia ◽  
David Gurarie ◽  
...  

Nitrogen-doped TiO2 has a great potential as a photocatalyst under visible light irradiation with applications in the removal of air and water pollutants, and the treatment of bacterial contaminations. In this study, nitrogen-doped TiO2 nanoparticles were synthesized via the sol–gel method and a post-annealing heat treatment approach. The effects of annealing treatment on the photocatalyst crystalline size and degree of crystallinity were analyzed. Methylene blue dye was used as the model water contaminant for the evaluation of the photoactivity of the synthesized nitrogen-doped TiO2 nanoparticles. The degradation of methylene blue was attributed to three mechanisms, i.e., adsorption, photocatalysis, and direct light photolysis. A kinetic model was developed to distinguish the impact of these three different mechanisms on the removal of contaminants. Adsorption and photocatalysis are heterogeneous processes for removing water organic contaminants. The characterization analysis demonstrates that they are relevant to the microstructures and surface chemical compositions of nitrogen-doped TiO2 photocatalysts. The processing–structure–performance relationship helped to determine the optimal processing parameters for nitrogen-doped TiO2 photocatalyst to achieve the best performance. While we used methylene blue as the model contaminant, the generalized quantitative model framework developed in this study can be extended to other types of contaminants after proper calibration.


2008 ◽  
Vol 33 (4) ◽  
pp. 993-996
Author(s):  
Junko Shimomura ◽  
Hajime Horikawa ◽  
Takashi Ogihara ◽  
Kazumi Kato ◽  
Hisao Suzuki ◽  
...  

2010 ◽  
Vol 159 ◽  
pp. 605-608
Author(s):  
Manisha Devi ◽  
Mukesh Kumar ◽  
A.M. Gaur

In this paper, our aim was to develop the Neodymium oxide (Nd2O3) based nano composites using sol gel method. This work is mainly focused on to study the synthesis of metal composites by sol gel method. We will also observe the morphologies and dimension of neodymium oxide doped nano composites are influenced due to alteration in growth parameters such as different composition or thermal treatment. The structure of the sample prepared was studied using optical microscope. The other objective would be to investigate the synthesis of modem oxide doped nano composites.


2018 ◽  
Vol 42 (14) ◽  
pp. 12001-12007 ◽  
Author(s):  
Kiros Guesh ◽  
Álvaro Mayoral ◽  
Yonas Chebude ◽  
María José López-Muñoz ◽  
Carlos Márquez-Álvarez ◽  
...  

Photocatalysts based on TiO2 supported on two different synthetic zeolites (faujasite CBV 760: SiO2/Al2O3 = 60 and mordenite CBV 21A, SiO2/Al2O3 = 20), containing 10 wt% and 40 wt% TiO2 loading, have been synthesized using a sol–gel method without any further calcination.


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