Preparation of SiO2 Encapsulated ZnO Nanopowders by Sol-Gel Method

2011 ◽  
Vol 412 ◽  
pp. 13-16
Author(s):  
Yan Xiang Wang ◽  
Jian Sun ◽  
Xiao Yan Li
Keyword(s):  
Liquid Phase ◽  
Sol Gel ◽  
Average Diameter ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Nanocrystals ◽  
Zno Particles ◽  
Low Temperature Crystallization ◽  
Temperature Crystallization

The shell-core structures of SiO2/ZnO nanopowders were obtained by simple two-step technique based on low-temperature crystallization from liquid phase. The influence of molar ratio of SiO2/ZnO in the reaction mixture on the morphology of obtained SiO2/ZnO nanopowders was studied. Crystalline structure of SiO2/ZnO nanocrystals obtained was proofed by the X-ray diffraction data. The average diameter of SiO2/ZnO nanocrystals was about 80~100nm according to FSEM and TEM data. It is shown that SiO2 components on the surface prevent the thermal interfusion of ZnO particles. Morphology and diameter of raw ZnO, SiO2/ZnO nanopowders prepared with molar ratio of SiO2/ZnO 0.1, 0.2, and 0.5 were almost same. When molar ratio of SiO2/ZnO was 0.5, ZnO core was coated with SiO2, and the thickness of shell was about 10nm. At the same time, SiO2 nanocrystals also formed the islands structure.

Controlled Growth of ZnO Nanocrystals on the Surface of SiO2 Spheres

2009 ◽  
Vol 151 ◽  
pp. 264-268 ◽  
Author(s):  
Yuliya V. Yermolayeva ◽  
Yuriy N. Savin ◽  
Alexander V. Tolmachev
Keyword(s):  
Average Diameter ◽  
Core Shell ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Nanocrystals ◽  
Transmission Electron ◽  
Zno Particles ◽  
One Step ◽  
Shell Particles ◽  
Sio2 Spheres

The “islands” of ZnO nanocrystals on amorphous monodisperse 200 nm SiO2 spheres (core-shell particles) were obtained by simple one-step technique based on low-temperature crystallization from liquid phase. The influence of starting reagents types and concentration of zinc ions in the reaction mixture on the morphology of ZnO shells obtained was studied. Crystalline structure of ZnO nanocrystals obtained was proofed by the X-ray diffraction data. The average diameter of ZnO nanocrystals on SiO2 spheres is 10 nm according to X-ray diffraction (XRD) and transmission electron microscopy (TEM) data. It was shown that SiO2/ZnO particles obtained have high luminescence characteristics. Photoluminescence spectra of core-shell SiO2/ZnO particles show two emission peaks centred at 386 nm and 570 nm. Core-shell SiO2/ZnO particles obtained are perspective for active photonic crystals creation for UV-spectral region.

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.

scholarly journals ZnFe2O4-TiO2Nanoparticles within Mesoporous MCM-41

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Aidong Tang ◽  
Yuehua Deng ◽  
Jiao Jin ◽  
Huaming Yang
Keyword(s):  
Sol Gel ◽  
Rutile Phase ◽  
Band Gap Energy ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Agglomeration Of Nanoparticles ◽  
Adsorption Desorption ◽  
Mcm 41

A novel nanocomposite ZnFe2O4-TiO2/MCM-41 (ZTM) was synthesized by a sol-gel method and characterized through X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), N2adsorption-desorption, Raman spectroscopy, and ultraviolet visible (UV-vis) spectrophotometry. The results confirmed the incorporation of ZnFe2O4-TiO2nanoparticles inside the pores of the mesoporous MCM-41 host without destroying its integrity. ZnFe2O4nanoparticles can inhibit the transformation of anatase into rutile phase of TiO2. Incorporation of ZnFe2O4-TiO2within MCM-41 avoided the agglomeration of nanoparticles and reduced the band gap energy of TiO2to enhance its visible light photocatalytic activity. UV-vis absorption edges of ZTM nanocomposites redshifted with the increase of Zn/Ti molar ratio. The nanocomposite approach could be a potential choice for enhancing the photoactivity of TiO2, indicating an interesting application in the photodegradation and photoelectric fields.

Study of Heating Effect on Specific Surface Area, and Changing Optical Properties of ZnO Nanocrystals

2011 ◽  
Vol 403-408 ◽  
pp. 1205-1210
Author(s):  
Jaleh Babak ◽  
Ashrafi Ghazaleh ◽  
Gholami Nasim ◽  
Azizian Saeid ◽  
Golbedaghi Reza ◽  
...  
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Energy Gap ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Zno Nanocrystals ◽  
Transmission Electron ◽  
Zno Nanocrystal

In this work ZnO nanocrystal powders have been synthesized by using Zinc acetate dehydrate as a precursor and sol-gel method. Then the products have been annealed at temperature of 200-1050°C, for 2 hours. The powders were characterized using X-ray diffraction (XRD), UV-vis absorption and photoluminescence (PL) spectroscopy. The morphology of refrence ZnO nanoparticles have been studied using Transmission Electron Microscope (TEM). During the annealing process, increase in nanocrystal size, defects and energy gap quantitative, and decrease in specific surface area have been observed.

The Effect of Stabiliser’s Molarity to the Growth of ZnO Nanorods

2011 ◽  
Vol 312-315 ◽  
pp. 99-103 ◽  
Author(s):  
Zuraida Khusaimi ◽  
Mohamad Hafiz Mamat ◽  
Mohd Zainizan Sahdan ◽  
Norbani Abdullah ◽  
Mohamad Rusop
Keyword(s):  
Sol Gel ◽  
Zno Nanorods ◽  
Structural Features ◽  
Zinc Nitrate ◽  
Molar Ratio ◽  
Nitrate Hexahydrate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Wet Chemical ◽  
Gel Preparation

A wet chemical approach, originating from sol-gel preparation, was adopted with the intention to develop a low-temperature benign method of preparation. ZnO nanorods are successfully grown in an aqueous medium. The precursor, zinc nitrate hexahydrate (Zn(NO3)2.6H2O), is stabilized by hexamethylene tetraamine (HMTA). The effect of changing the molarity of HMTA to the structural orientation of ZnO nanorods is investigated. X-ray diffraction of the synthesized ZnO shows hexagonal zincite structure. The structural features of the nanocrystalline ZnO were studied by SEM. Structural features, surface morphology and differences in lattice orientation are seemingly influenced by varying the Zn2+: HMTA molar ratio. The formation of ZnO nanorods with blunt and sharp tips is found to be significantly affected by this ratio.

Synthesis, Characterization and Photocatalytic Activity of Nb-Doped TiO2 Nanoparticles

2012 ◽  
Vol 455-456 ◽  
pp. 110-114 ◽  
Author(s):  
Xuan Dong Li ◽  
Xi Jiang Han ◽  
Wen Ying Wang ◽  
Xiao Hong Liu ◽  
Yan Wang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Methyl Orange ◽  
Photoelectron Spectroscopy ◽  
Sol Gel ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Doped Tio2 ◽  
X Ray ◽  
Vis Spectroscopy

Nb-doped TiO2 powders with different concentrations of Nb have been synthesized by a sol-gel method and characterized by a series of technologies including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and UV-vis spectroscopy. The photocatalytic activity of Nb-doped TiO2 is evaluated by degradation efficiency of methyl orange in aqueous solution. The results indicate that the photocatalytic activity of Nb-doped TiO2 synthesized with a Nb/Ti molar ratio of 5% is higher than that of TiO2 under the visible light.

Preparation and Photocatalytic Preoperty of BaV2O6 Photocatalyst by Liquid-Phase Deposition Method

2012 ◽  
Vol 460 ◽  
pp. 131-134
Author(s):  
Min Wang ◽  
Qiong Liu ◽  
Hai Yan Luan
Keyword(s):  
Photocatalytic Activity ◽  
Liquid Phase ◽  
Calcination Temperature ◽  
Molar Ratio ◽  
Liquid Phase Deposition ◽  
Deposition Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Synthesized Materials

BaV2O6 photocatalyst was prepared by liquid-phase deposition method in paper and different calcination temperature effecting photocatalytic activity were investigated. X-ray diffraction (XRD) has been employed to characterize the as-synthesized materials. The photocatalytic activity was evaluated by degradation of Methy lorange(MO) under the UV-light.It was found that as-prepared BaV2O6 with molar ratio of V5+ to Ba3+ be 2:1, pH=7 and calcinated under 500°C for 4h exhibits higher activity than any other calcination temperature. The highest degragation rate was about 65% or so in 100min.

Morphology and Phase Composition of Sol-Gel Derived Aluminum Borate Nanowhiskers

2015 ◽  
Vol 659 ◽  
pp. 121-126 ◽  
Author(s):  
Pat Sooksaen
Keyword(s):  
Fourier Transform ◽  
Phase Composition ◽  
Sol Gel ◽  
Molar Ratio ◽  
Aluminum Borate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Higher Temperature ◽  
Sol Gel Synthesis ◽  
Scanning Electron

Aluminium borate nanowhiskers with varying aspect ratio were synthesized via sol–gel synthesis. The morphology of aluminum borate (Al4B2O9 and Al18B4O33) nanowhiskers could be controlled by varying the aluminum to boron (Al:B) molar ratio in the sol–gel derived precursors. Sintering temperatures (850 and 1100°C) and sintering times (4 and 32 hours) also affected the phase composition and size of the nanowhiskers. Citric acid was also added in the sol–gel derived precursors as a surface stabilizer for obtaining uniform finely dispersed nanostructures. Fine nanowhiskers were obtained by the calcination at 850°C, whereas higher temperature of 1100°C led to thicker and longer nanowhiskers and became rod-like crystals. The morphology and phase composition were investigated by field emission scanning electron microscope and X-ray diffraction. Chemical bond vibrations in the synthesized nanowhiskers were investigated by Fourier-transform infrared spectroscopy.

scholarly journals Synthesis of Ca-Doped Three-Dimensionally Ordered Macroporous Catalysts for Transesterification

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Tanat Chokpanyarat ◽  
Vittaya Punsuvon ◽  
Supakit Achiwawanich
Keyword(s):  
Reaction Time ◽  
Catalyst Concentration ◽  
Sol Gel ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
The Novel ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hierarchical Porous ◽  
Ordered Macroporous

The novel three-dimensionally ordered macroporous (3DOM) CaO/SiO2, 3DOM CaO/Al2O3, and 3DOM Ca12Al14O32Cl2 catalysts for biodiesel transesterification were prepared by sol-gel method. The 3DOM catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). The hierarchical porous structure was achieved; however, only 3DOM CaO/Al2O3 and 3DOM Ca12Al14O32Cl2 catalysts were used for transesterification due to high amount of active CaO. Various parameters such as methanol to oil molar ratio, catalyst concentration, reaction time, and their influence on the biodiesel production were studied. The result showed that 99.0% RPO conversion was achieved using the 3DOM Ca12Al14O33Cl2 as a catalyst under the optimal condition of 12 : 1 methanol to oil molar ratio and 6 wt.% catalyst with reaction time of 3 hours at 65°C.

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.

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