نتایج جستجو برای: Ti-Si mixed oxides
تعداد نتایج: 345210 فیلتر نتایج به سال:
the nanoparticles of ti-si mixed oxides (ntso) with rutile structure were prepared by sol-gel method in a mixture of alcohol and water as solvent. the solid product was characterized by xrd, ftir, sem, tem, uv, tga and laser raman spectroscopy. the catalytic activity of ntso (5-10 nm) was investigated in the epoxidation of cis stilbene, trans stilbene, and norbornene by using oxidants such as t...
the nanoparticles of ni–si mixed oxides were prepared by co-precipitation method using nickel nitrate; ni(no3)2 6h2o and tetraethylorthosilicate (teos). the products were characterized by x-ray diffraction (xrd), transmission electron microscopy (tem), and hydrogen temperature program reduction (h2-tpr). the results revealed that ni–si mixed oxides particles were obtained with average particle ...
The nanoparticles of Ni–Si mixed oxides were prepared by co-precipitation method using nickel nitrate; Ni(NO3)2 6H2O and tetraethylorthosilicate (TEOS). The products were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and hydrogen temperature program reduction (H2-TPR). The results revealed that Ni–Si mixed oxides particles were obtained with average particle ...
The nanoparticles of Ti-Si mixed oxides (NTSO) with Rutile structure were prepared by sol-gel method in a mixture of alcohol and water as solvent. The solid product was characterized by XRD, FTIR, SEM, TEM, UV, TGA and laser Raman spectroscopy. The catalytic activity of NTSO (5-10 nm) was investigated in the epoxidation of cis stilbene, trans stilbene, and norbornene by using oxidants such as t...
As a newly developed conductive ceramic with wide application prospects, the electrochemical corrosion behavior of Ti3SiC2 in 3.5% NaCl solution was investigated by potentiodynamic polarization, potentiostatic polarization and electrochemical impedance spectroscopy. Commercially pure titanium (CP Ti) was selected for comparative, and cooperated with XRD, XPS, SEM, the passivation behavior, corr...
A series of mixed iron and titanium oxide coprecipitates ranging in composition between 0 < Ti/Ti + Fe < 1 was synthesized and aged under varying conditions of pH, temperature and time in order to establish a working model for pedogenic titanium and titano-ferric oxides. X-ray powder diffraction (XRD), selective chemical dissolution, magnetic susceptibility, charge distribution and electron opt...
سنگ¬های آتشفشانی جنوب غرب اردستان، واقع در بخش مرکزی کمربند ماگمایی ارومیه – دختر، عمدتاً متشکل از سنگ¬های بازیک و فلسیک و اندک سنگ¬های حدواسط می باشد. سنگ¬های آتشفشانی غنی از لیتوفیل، از عناصر ti ,zr و برخی عناصر سنگین همچون yb و lu نیز غنی می¬باشند. به نظر می¬رسد که این سنگ ها حاصل درجه ذوب بخشی کم ولی گسترده یک گوشته تهی شده (همانگونه که آنومالی منفی nb-ta دلالت می¬نماید) باشد. برعکس، سنگ¬های...
The structure of the oxide as a nucleus for intragranular ferrite formation in low O weld metal and mechanism Mn depleted zone (MDZ) at oxide/matrix interface were studied using liquid-tin quenched specimens high-temperature conditions during laser welding carbon Ti added steel. At high temperature 1720 K, MDZ is formed around complex oxides (Ti,Mn)3O5, (Ti,Mn)2O3, liquid phase (containing Si, ...
We demonstrate a new design concept where the interaction between silica nanoparticles (about 1.5 nm in diameter) with titania nanoparticles (anatase, about 4 nm or 6 nm in diameter) guides a successful formation of mesoporous titania with crystalline walls and controllable porosity. At an appropriate solution pH (~1.5, depending on the deprotonation tendencies of two types of nanoparticles), t...
It can be difficult to determine the number of active atoms accessible to the fluid phase in mixed oxide catalysts, as required for obtaining true turnover frequencies (TOF). Here, we utilize the selective titration of surface Ti atoms with phenylphosphonic acid (PPA) on TiO2–SiO2 materials to estimate the number of reactant-accessible sites. TiO2–SiO2 composites were synthesized over a range o...
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