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Free keywords:
Spinels preparation;
High surface area;
Zeolites;
Precursors
Abstract:
Transition metal spinels with particle sizes in the nanometer range crystallize from transition metal exchanged zeolites during calcination. The spinels are covered by an amorphous silica which prohibits access to the surface of the spinel particles. Dissolution of the silica in alkaline solution leads to spinels with high surface areas, caused by small particles. The composition of the zeolites as well as the calcination time and temperature are important parameters which take influence on the properties of the obtained spinels. Correct adjustment of these parameters enables control of the spinel particle sizes. The obtained transition metal spinels, having high surface areas up to 200 m2/g, may find use as catalysts or catalyst supports.
