نتایج جستجو برای: ceo2
تعداد نتایج: 2688 فیلتر نتایج به سال:
This article reports the green fabrication of cerium oxide nanoparticles (CeO2 NPs) using Olea europaea leaf extract and their applications as effective antimicrobial agents. O. europaea leaf extract functions as a chelating agent for reduction of cerium nitrate. The resulting CeO2 NPs exhibit pure single-face cubic structure, which is examined by X-ray diffraction, with a uniform spherical sha...
Diffusion processes and reactions of H at stoichiometric and reduced CeO2(111) surfaces have been studied by using density functional theory calculations corrected by on-site Coulomb interactions (DFT + U). Oxygen vacancies on the surface are determined to be able to significantly affect the behavior of H by modifying the charge of surface lattice O through the occurrence of Ce(3+). It has been...
In this work, nanostructured CeO2 microspheres with high surface area and mesoporosity were prepared by the coprecipitation method, in absence of a template. The reaction between cerium nitrate and concentrated formic acid produced cerium formate, at room temperature. Further, calcination at 300 °C yielded single-phase CeO2 microspheres, with a diameter in the range 0.5-2.6 μm, the surface of t...
Oxygen storage/release (OSC) capacity is an important feature common to all three-way catalysts that enables them to efficiently remove harmful compounds such as hydrocarbons, CO and NOx in automotive exhaust gases. In this report, three types of CeO2-ZrO2 (Ce:Zr = 1:1 molar ratio) compounds with different OSC were characterized by means of XRD (X-ray diffraction) and XAFS (X-ray absorption fin...
We report the microwave synthesis and characterization of Au and Pd nanoparticle catalysts supported on CeO2, CuO, and ZnO nanoparticles for CO oxidation. The results indicate that supported Au/CeO2 catalysts exhibit excellent activity for low-temperature CO oxidation. The Pd/CeO2 catalyst shows a uniform dispersion of Pd nanoparticles with a narrow size distribution within the ceria support. A...
Ultrathin CeO2 nanowires with a diameter of 5 nm and an aspect ratio of more than 100 can be prepared by a one-step refluxing approach in a mixed solvent composed of water and ethanol without using any templates or surfactants. The formation mechanism of the as-synthesized ultrathin nanowires has been investigated. The as-synthesized CeO2 nanowires with a high surface area of 125.31 m2 g-1 exhi...
The performances of different promoters (CeO2, ZrO2 and Ce0.5Zr0.5O2 solid solution) modified Pd/SiC catalysts for methane combustion are studied. XRD and XPS results showed that Zr 4+ could be incorporated into the CeO2 lattice to form Zr0.5Ce0.5O2 solid solution. The catalytic activities of Pd/CeO2/SiC and Pd/ZrO2/SiC are lower than that of Pd/Zr0.5Ce0.5O2/SiC. The Pd/Zr0.5Ce0.5O2/SiC catalys...
Tin was deposited in the amount of 0.4 and 0.8 nm onto CeO2(111) surface by molecular beam deposition at the temperature of 520 K. The interaction of tin with cerium oxide was studied with use of XPS, UPS and RPES (Resonant Photoelectron Spectroscopy). The strong tin – ceria interaction led to the Ce(4-nx)+Snxn+O22compound formation. It was accompanied with partial reduction of CeO2 observed as...
The phase formation of Ni-Ce composites onto a carbon steel electrode was investigated using electrochemical deposition. The anticorrosive properties of composite coating in 0.1 mol L HCl solution were studied by Tafel polarization and electrochemical impedance spectroscopy (EIS). Incorporation of CeO2 particles into the Ni matrices was found to improve corrosion resistance of pure Ni coatings....
The complete oxidation of n-Hexane and iso-Octane was studied individually in a fixed bed tubular flow reactor over CuO-CeO2 catalysts synthesized via four different methods namely urea-nitrate combustion method, urea gelation/co-precipitation method, citric acid sol-gel method and co-impregnation method. Laser diffraction was employed in catalysts characterization. The results obtained from th...
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