scholarly journals Synthesis of bimodally porous titania powders by hydrolysis of titanium tetraisopropoxide

2000 ◽  
Vol 15 (11) ◽  
pp. 2322-2329 ◽  
Author(s):  
Ki Chang Song ◽  
Sotiris E. Pratsinis
Keyword(s):  
Phase Composition ◽  
Calcination Temperature ◽  
Water Concentration ◽  
Nitrogen Adsorption ◽  
Molar Ratio ◽  
Titanium Tetraisopropoxide ◽  
X Ray Diffraction ◽  
Porous Titania ◽  
Nitrogen Adsorption Isotherms ◽  
Hydrolysis Of

Bimodally porous titania powders with controlled phase composition and porosity were made by hydrolysis of titanium tetraisopropoxide (TTIP) and calcination. The extent of calcination was followed by thermogravimetric differential thermal analysis and Fourier transform infrared spectroscopy. The specific surface area (SSA) of the powders ranged from 10 to 500 m2/g as determined by nitrogen adsorption. The SSA increased by decreasing either the water concentration during hydrolysis or the calcination temperature. The pore size distribution was bimodal with fine intraparticle pore diameters at 1–6 nm and larger interparticle pore diameters at 30–120 nm as determined by nitrogen adsorption isotherms. The particle phase composition as determined by x-ray diffraction ranged from amorphous to crystalline anatase and rutile largely proportional to the calcination temperature and to a lesser extent on the initial H2O/TTIP molar ratio.

scholarly journals Thermal Preparation and Application of a Novel Silicon Fertilizer Using Talc and Calcium Carbonate as Starting Materials

Molecules ◽  
2021 ◽  
Vol 26 (15) ◽  
pp. 4493
Author(s):  
Yian Wang ◽  
Jie Zhang ◽  
Junjian Zheng ◽  
Hua Lin ◽  
Gongning Chen ◽  
...  
Keyword(s):  
Calcium Carbonate ◽  
Calcination Temperature ◽  
Nitrogen Adsorption ◽  
Preparation Condition ◽  
Molar Ratio ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Adsorption Analysis ◽  
Si Content ◽  
Calcination Method

The deficiency of available silicon (Si) incurred by year-round agricultural and horticultural practices highlights the significance of Si fertilization for soil replenishment. This study focuses on a novel and economical route for the synthesis of Si fertilizer via the calcination method using talc and calcium carbonate (CaCO3) as starting materials. The molar ratio of talc to CaCO3 of 1:2.0, calcination temperature of 1150 °C and calcination time of 120 min were identified as the optimal conditions to maximize the available Si content of the prepared Si fertilizer. X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR) characterizations elucidate the principles of the calcination temperature-dependent microstructure evolution of Si fertilizers, and the akermanite Ca2Mg(Si2O7) and merwinite Ca3Mg(SiO4)2 were identified as the primary silicates products. The results of release and solubility experiments suggest the content of available metallic element and slow-release property of the Si fertilizer obtained at the optimum preparation condition (Si-OPC). The surface morphology and properties of Si-OPC were illuminated by the results of scanning electron microscope (SEM), surface area and nitrogen adsorption analysis. The acceleration action of CaCO3 in the decomposition process of talc was demonstrated by the thermogravimetry-differential scanning calorimetry (TG-DSC) test. The pot experiment corroborates that 5 g kg−1 soil Si-OPC application sufficed to facilitate the pakchoi growth by providing nutrient elements. This evidence indicates the prepared Si fertilizer as a promising candidate for Si-deficient soil replenishment.

scholarly journals Carbon-coated titania nanostructured particles: Continuous, one-step flame-synthesis

2003 ◽  
Vol 18 (11) ◽  
pp. 2670-2676 ◽  
Author(s):  
Hendrik K. Kammler ◽  
Sotiris E. Pratsinis
Keyword(s):  
Crystal Size ◽  
Nitrogen Adsorption ◽  
Titanium Tetraisopropoxide ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
Nanostructured Particles ◽  
Carbon Particles ◽  
Transmission Electron ◽  
Carbon Coated ◽  
One Step

Concurrent synthesis of titania-carbon nanoparticles (up to 52 wt.% in C) was studied in a diffusion flame aerosol reactor by combustion of titanium tetraisopropoxide and acetylene. These graphitically layered carbon-coated titania particles were characterized by high-resolution transmission electron microscopy (HRTEM), with elemental mapping of C and Ti, x-ray diffraction (XRD), and nitrogen adsorption [Brunauer-Emmett-Teller (BET)]. The specific surface area of the powder was controlled by the acetylene flow rate from 29 to 62 m2/g as the rutile content decreased from 68 to 17 wt.%. Light blue titania suboxides formed at low acetylene flow rates. The average XRD crystal size of TiO2 decreased steadily with increasing carbon content of the composite powders, while the average BET primary particle size calculated from nitrogen adsorption decreased first and then approached a constant value. The latter is attributed to the formation of individual carbon particles next to carbon-coated titania particles as observed by HRTEM and electron spectroscopic imaging.

Catalytic Hydrolysis of Hydrogen Cyanide on Cu-Al Catalyst

2015 ◽  
Vol 1094 ◽  
pp. 15-19
Author(s):  
Lin Xia Yan ◽  
Sen Lin Tian ◽  
Qiu Lin Zhang
Keyword(s):  
Calcination Temperature ◽  
Hydrogen Cyanide ◽  
Influence Factor ◽  
Ph Value ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Cu Content ◽  
Co Precipitation ◽  
The Impact ◽  
Hydrolysis Of

Cu-Al catalysts were synthesized by the co-precipitation method to study hydrolysis of hydrogen cyanide. During the synthesis, the impact of Cu/Al molar ratio, pH value and calcination temperature was investigated and the best synthesis condition was found. The results indicate that the remove of hydrogen cyanide first increases and then decreases with increasing Cu/Al molar ratio, pH value and calcination temperature, which reaches the maxima and remains above 95% at 360 min when Cu/Al molar ratio is 2:1, pH value is approximately 8.0 and calcination temperature is 400°C around. The analysis of X-ray diffraction (XRD) shows that Cu content is the main influence factor at Cu/Al molar ratio below 2:1 whereas crystallinity of catalysts is the key factor at Cu/Al molar ratio above 2:1.

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.

Co-Precipitation Synthesis of BiFeO3 Powders

2010 ◽  
Vol 105-106 ◽  
pp. 286-288 ◽  
Author(s):  
Hai Yang Bo ◽  
Guo Qiang Tan ◽  
Hong Yan Miao ◽  
Ao Xia
Keyword(s):  
Calcination Temperature ◽  
Bismuth Ferrite ◽  
Precipitation Method ◽  
Molar Ratio ◽  
Diffraction Field ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Infrared Spectrophotometer ◽  
Lower Temperature ◽  
Co Precipitation

Bismuth ferrite powders were synthesized by a simple citric acid complexing co-precipitation method at much lower temperature of 600°C. The work studies the calcination temperature and molar ratio of Fe and Bi on the structure and morphology. The as-prepared BiFeO3 powder was characterized by X-ray diffraction, field emission scanning electron microscopy, transmission electron microscope and Fourier transform infrared spectrophotometer. The result shows that the phase pure BiFeO3 powders with cubic morphology were prepared as the calcination temperature was 600°C and molar ratio of Fe and Bi was 1:1. The nanoparticles was uniform with the size of about 200nm.

scholarly journals Characterization and evaluation of the photocatalytic activity of oxides based on TiO2 synthesized by hydrolysis controlled by the use of water/acetone mixtures

2020 ◽  
Vol 2 ◽  
pp. e11
Author(s):  
Werick A. Machado ◽  
Antonio Eduardo da Hora Machado
Keyword(s):  
Pure Water ◽  
Synthesis Process ◽  
Titanium Tetraisopropoxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
A Value ◽  
Ponceau 4R ◽  
Crystalline Oxides ◽  
Hydrolysis Of ◽  
Controlled Hydrolysis

New photocatalysts based on TiO2 were synthesized and characterized. The synthesis involved the controlled hydrolysis of titanium tetraisopropoxide using water containing different proportions of acetone. X-ray diffraction analyses combined with Raman spectroscopy revealed crystalline oxides characterized by the coexistence of the anatase and brookite phases. The Rietveld refinement of diffractograms showed that the presence of acetone in the synthesis process influenced the composition of these crystalline phases, with the proportion of brookite growing from 13% to 22% with the addition of this solvent in the synthesis process. The BET isotherms revealed that these materials are mesoporous with surface area approximately 12% higher than that of the oxide prepared from hydrolysis using pure water. The photocatalytic potential of these oxides was evaluated by means degradation tests using the dyes Ponceau 4R and Reactive Red 120 as oxidizable substrates. The values achieved using the most efficient photocatalyst among the synthesized oxides were, respectively, 83% and 79% for mineralization, and 100% for discoloration of these dyes. This same oxide loaded with 0.5% of platinum and suspended in a 5:1 v/v water/methanol mixture, produced 56 mmol of gaseous hydrogen in 5 h of reaction, a specific hydrogen production rate of 138.5 mmol h−1g−1, a value 60% higher than that achieved using TiO2 P25 under similar conditions.

Porous Ceramic Humidity Sensors Using Sol-Gel Processed ZrTiO4 Nanoparticles

2006 ◽  
Vol 45 ◽  
pp. 1803-1808 ◽  
Author(s):  
I.C. Cosentino ◽  
E.N.S. Muccillo ◽  
F.M. Vichi ◽  
R. Muccillo
Keyword(s):  
Porous Ceramic ◽  
Mercury Porosimetry ◽  
Sol Gel ◽  
Average Particle Size ◽  
Nitrogen Adsorption ◽  
Zirconium Oxychloride ◽  
Average Particle ◽  
Titanium Tetraisopropoxide ◽  
X Ray Diffraction ◽  
Adsorption Analysis

Ceramic ZrTiO4 powders were prepared by a sol-gel method using zirconium oxychloride and titanium tetraisopropoxide. In situ high temperature X-ray diffraction results show that crystallization of the amorphous gel starts at 400°C. Single-phase ZrTiO4 nanoparticles of 46 nm average particle size, determined by nitrogen adsorption analysis, were obtained after heat treatment at 450°C for 1 h. After pressing these sinteractive powders, pellets with controlled pore size distribution were obtained by sintering at temperatures as low as 400°C. The analysis of pores by mercury porosimetry gives an average porosity of 45%. The electrical resistivity, determined by impedance spectroscopy measurements at 24°C under different humidity environments, shows the ability of these pellets to adsorb water vapor in the porous surfaces.

Hydrothermal Synthesis of Nanosized TiO2 Using Basic Peptizing Agents and their Photocatalytic Activity on the Decomposition of Orange II

2007 ◽  
Vol 544-545 ◽  
pp. 71-74
Author(s):  
Jun Ho Kim ◽  
Kwon Taek Lim ◽  
Gun Dae Lee ◽  
Seong Soo Park ◽  
Seong Soo Hong
Keyword(s):  
Photocatalytic Activity ◽  
Uv Light ◽  
Batch Reactor ◽  
Anatase Phase ◽  
Photocatalytic Decomposition ◽  
Molar Ratio ◽  
Orange Ii ◽  
Titanium Tetraisopropoxide ◽  
Peptizing Agent ◽  
Hydrolysis Of

TiO2 nanoparticles were prepared using the hydrolysis of titanium tetraisopropoxide (TTIP) using TENOH as a peptizing agent in the hydrothermal method. The physical properties of prepared nanosized TiO2 particles were investigated. The photocatalytic degradation of orange II has been studied using a batch reactor in the presence of UV light. The crystallite size of the anatase phase is increased from 15 to 30 nm as the molar ratio of TENOH/TTIP increases from 0.1 to 1.0. The titania particle prepared at TENOH/TTIP molar ratio=0.1 shows the highest activity on the photocatalytic decomposition of orange II and the photocatalytic activity decreases according to an increase in TENOH/TTIP molar ratio. In addition, the titania particles prepared at 160oC shows the highest activity on the photocatalytic decomposition of orange II

Effects of Fuel Content and Calcination Procedure on Phase Composition and Microstructure of LiMn2O4 Prepared by Solution Combustion Synthesis

2008 ◽  
Vol 368-372 ◽  
pp. 296-298 ◽  
Author(s):  
Jun Ming Guo ◽  
Gui Yang Liu ◽  
Jie Liu ◽  
De Wei Guo ◽  
Ke Xin Chen ◽  
...  
Keyword(s):  
Grain Size ◽  
Phase Composition ◽  
Combustion Synthesis ◽  
Calcination Temperature ◽  
Solution Combustion Synthesis ◽  
X Ray Diffraction ◽  
Spinel Limn2o4 ◽  
Solution Combustion ◽  
Phase Purity ◽  
Diffraction Patterns

Spinel LiMn2O4 was prepared by solution combustion synthesis. The effect of fuel content and calcination procedure on phase composition and microscopic structure of LiMn2O4 was studied. X-ray diffraction patterns showed that fuel content had no obvious influence on the grain size and phase purity of LiMn2O4. Higher calcination temperature led to higher phase purity, lager grain size, and better crystallization of resultant LiMn2O4. Below 600°C the effect of calcination time was inconspicuous, which became notable above 700°C. Scanning electron microscope images showed that nanocrystalline LiMn2O4 was obtained when the calcination temperature was lower than 600°C and the grain size increased at higher temperatures.

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