wizyta

od 2020-09-20

Title: Generation of iron active species in MCM-41 materials

Source: Studies in Surface Science and Catalysis A

Year : 2005

Abstract:

A new method, the immobilisation or ferroceneacetic acid (FAA) on various MCM-41 mesoporous molecular sieves (containing Si or Si+Al) followed by calcination at 773 K has been applied for the formation of iron active species. The structural, surface and catalytic properties of these materials, characterised by N-2 adsorption/desorption, XRD, Al-27 NMR, ESR, and Mossbauer spectroscopy as well as test reactions, were compared with those of materials prepared via commonly used impregnation methods. Contrary to Fe-impregnated samples, Fe oxides species were only slightly detected in the solids modified by FAA followed by calcination. It is evidenced that the new technique applied for Fe-modification gives rise to the significantly higher activity (in isopropanol decomposition and acetonylacetone cyclization) reached thanks to a better isolation and/or dispersion of Fe3+ species. The presence of Al in the sample influences the Fe3+ reduction under vacuum.

DOI: 10.1016/s0167-2991(05)80419-7   (Pobrane:  2021-01-02)