engleski

Characterization of sol-gel-derived ceria nanoparticles doped with manganese

Ceria (CeO2), with its stable fluorite structure and two interchangeable oxidation states, Ce4+ and Ce3+ has many excellent properties enabling its widespread use. Owing to the shift between Ce4+ and Ce3+, oxygen vacancies occur within the lattice resulting with high oxygen mobility and oxygen storage capacity of ceria. Nanoparticles have a larger specific surface area compared to bulk material and thus provide faster oxygen exchange, resulting in better catalytic activity. It is belived that incorporation of Mn atoms in ceria crystal lattice will ensure even better catalytic propeties for oxidation of numerous compounds, for instance: carbon monoxide, phenol, and volatile organic compounds. With all this in mind, nano-ceria doped with manganese in various amounts was prepared via sol-gel synthesis. The as prepared samples were thermally treated to observe coarsening and thermal stability. All samples, as prepared and annealed, were studied by X-ray diffraction (XRD). Along with ceria, manganese (II) 2, 4-pentadionate [Mn(C5H7O2)2] lines appear in all of the as prepared samples doped with manganese. Crystallite size decrease due to incorporation of Mn atoms in the ceria crystal lattice was established via Scherrer method. The determination of surface properties as well as pore volume was acquired using Brunauer-Emmet-Teller (BET) N2 gas adsorption- desorption isotherms. Scanning electron microscope (SEM) analysis gave insight into sample morphology showing ceria nanoparticles. Thermally induced changes were monitored via differential thermal analysis and thermo- gravimetric analysis (DTA/TGA) giving insight into the decomposition of leftover organic phase.

Sol-gel, doping, ceria, maganese

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