نتایج جستجو برای: calcination time
تعداد نتایج: 1893765 فیلتر نتایج به سال:
Polymethylmethacrylate (PMMA)/ceria composite fibres were synthesized by using a sequential combination of polymer electrospinning, spray-coating with a sol, and a final calcination step to yield microstructured ceria tubes, which are composed of nanocrystalline ceria particles. The PMMA template is removed from the organic/inorganic hybrid material by radio frequency (rf) plasma etching follow...
We have demonstrated the synthesis of γ-Fe2O3 nano-particles through a facile and novel calcination process in the air. There is no pH regulation, gas atmosphere, additive, centrifugation or other complicated procedures during the preparing process. A detailed formation process of the nano-particles is proposed, and DMF as a polar solvent may slower the reaction process of calcination. The stru...
Precipitation was carried out to obtain manganese carbonate by adding a precipitating agent, sodium (NaCO3). This followed calcination of the (MnCO3) dioxide (MnO2). For precipitation tests, pH ranging from 8 10, time one two hours, and temperature 25°C 50°C are parameters that considered. The MnCO3 is under following conditions: (1, 2, 3, 4 hours) (370°C, 420°C, 470°C). It should be noted rang...
Ceria-titania solutions with compositions of Ce0.9Ti0.1O2 and Ce0.8Ti0.2O2 were prepared by the citric-acid (Pechini) method and characterized using x-ray diffraction (XRD) for structure, coulometric titration for redox thermodynamics, and water-gas-shift (WGS) reaction rates. Following calcination at 973 K, XRD suggests that the mixed oxides exist as single-phase, fluorite structures, although...
The structure of the mesoporous silica SBA-16 has been interrogated by careful elimination of the organic templating agent using ozone treatment. It is shown that the as-synthesised material consists of large cages connected by very narrow, ca. 7 Å, windows. These windows open up to about 20 Å following a calcination treatment that suggests that the functionality of SBA-16 could be changed mark...
Three quarters of the world’s phosphate deposits are of sedimentary origin and 75%–80% of those include carbonate gangue. In this study, carbonate sedimentary phosphate deposits of the Lar Mountains of southwest Iran are studied. These deposits consist mainly of calcite, fluorapatite, quartz, kaolinite and illite, with an average P2O5 grade of 9%–10% (low-grade). Various pre-processing and proc...
The composites graphite/ZnO were prepared using calcination method. Zinc chloride (ZnCl2) and sodium carbonate (Na2CO3) were used for synthesis of zinc oxide (ZnO), whereas micromilled and natural graphite were used as the matrix for ZnO nanoparticles growing. During the reaction of ZnCl2 with saturated aqueous solution of Na2CO3 new compound Na2Zn3(CO3)4•(H2O)3 originates. During the calcinati...
Bimetallic catalysts (Co:Mo ≈ 2:1 in atomic ratio) were prepared on quartz substrates from metal acetate solutions using a procedure of dip coating, followed by calcination and reduction. High-purity single-walled carbon nanotubes (SWNTs) 1–2 nm in diameter were grown densely (~1.0×10 17 m-2) and vertically on these substrates during an alcohol catalytic chemical vapor deposition process. To cl...
Mixed copper-cerium oxides were prepared by two methods leading to different wpper species in the as-prepared material. At the catalyst operating temperature (300400°C) and above, the same copper species was present irrespective of the prepration technique. A solid solution having the same fluorite structure as that of pure CeQ was formed and remained stable after calcination to 100O0C. At temp...
The co-condensation of a tetraethoxysilane molecule on a neutral n-octylamine surfactant template is a convenient synthetic methodology for mesostructured material preparations. Distinct routes of template removal were investigated. The neutral surfactant was removed by calcination, hot solvent extraction, heating at 150 uC, in vacuo at room temperature and at 100 uC, and air drying, with the p...
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