engleski

Sol-gel synthesis of ceria: Study of cerium(III) acetylacetonate hydrolysis kinetics by thermochemical methods

Solid oxides show special properties if prepared as very fine powders, in the submicrometer range. These nanopowders allow the preparation of special catalysts, as for example ceria nanopowder catalysts that show improved oxygen absorption/desorption properties due to the easier valence state change and generation of oxygen vacancies at increased rate. There are numerous methods of nanopowder preparation and one of them is the sol-gel process, basically a bottom-up method that generates reactive „molecules“ that agglomerate into nano-clusters, depending on the particular use of the starting materials, temperature, rate of reaction, solvent, mixing rate etc. Finely tuned sol-gel process after the final calcination of the dried gel produces nanopowders of great homogeneity. In this work, the first step of sol-gel process, i.e. precursor hydrolysis/gelation has been studied by thermochemical/calorimetric method of measurement of the heat generation rate during the slow hydrolysis of cerium (III)-acetylacetonate. This is one, but important step of gel formation that is otherwise difficult to study, i.e. it is not well characterized in the open literature in general. Toward that goal, a laboratory setup was constructed and characterized for its sensitivity and time stability in order to study slow chemical and structural changes of sol-gel transition.

Sol‐gel ; Ceria(III)‐acetylacetonate ; Ceria nanopowder ; Calorimeter ; Rate of hydrolysis

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