Sol-gel sinteza cerijeva (IV) oksida dopiranog manganom ; Sol-gel synthesis of manganese-doped ceria

Cerijev(IV) oksid te cerijev(IV) oksid dopiran manganom pripravljeni su sol-gel procesom. Korišteni su prekursori cerijev acetil acetonat hidrat i manganov acetil acetonat. Nakon sinteze provedena je karakterizacija dobivenih materijala metodama pretražne elektronske mikroskopije, rendgenske difrakcijske analize, infracrvene spektroskopije s Fourierovim transformacijama te diferencijalne termalne analize i termogravimetrijske analize. Provedenim analizama utvrđeno je da je postignuta hidroliza prekursora te je došlo do formiranja gela. Toplinska evolucija uzoraka detaljno je karakterizirana pri različitim temperaturama, te su 500 °C i 2 h izabrani kao parametri termičke obrade. Čisti CeO2 je jedina kristalna faza dobivena toplinskom obradom uzoraka. Parametar jedinične ćelije a ukazuje na ulazak mangana u kristalnu rešetku CeO2. Provedena je kinetička analiza te su određene energije aktivacije okrupnjavanja svih uzoraka. Dopirani uzorci imaju manje veličine kristalita i povećanu toplinsku stabilnost u odnosu na čisti CeO2. ; Manganase-doped ceria and pure ceria samples were prepared by the sol-gel process. Cerium acetylacetonae hydrate and manganase acetylacetonate were used as precursors. The characterization of obtained samples has been conducted by scanning electron microscopy, X-ray diffraction, Fourier transformed infra-red spectroscopy, as well as differential thermal and thermo-gravimetric analysis. It was established that hydrolysis of the precursors and gel formation was achieved. Thermal evolution on several different temperatures was characterized in details. A temperature of 500 °C and a 2 h duration were selected as thermal treatment parameters. Pure ceria was the only crystal phase obtained by thermal treatment with lattice constant a revealing the entrance of manganese in crystal lattice of ceria. Kinetic analysis was conducted and coarsening activation energies of samples were determined. Doped samples displayed smaller crystallite size and increased thermal stability in comparison with pure ...