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Nanomaterials with a Multimodal Pore Structure Based on the MFI-type Zeolite

Burkat-Dulak A., Pashkova V., Pudło W., Włoch E., Jarzębski A., Derewinski M.

Polish Journal of Chemistry

2008

Vol. 82, nr 9

1809-1822

Synthesis and characterization of new multimodal porous systems containing thin MFI zeolitic films is reported. These films cover the internal surface of the meso- and macroporous silica-alumina monoliths. They are easily accessible through the open porous structure retained in the partially recrystallized, originally amorphous monolith. When the mesoporous Al-SBA-15 sieves are used in stead of monoliths, a controlled hydrothermal process results in the formation of the MFI nanodomains dispersed in the walls that separate mesopores hexagonally arranged. These do mains possess strong acidic sites of the zeolitic type, but the original ordering of mesopores in the parent material is very well retained. A simple method for the synthesis of the MFI crystals containing both meso- and macrovoids is also proposed. It makes use of the suspended mono- and polydispersed carbon particles that serve as porogens. Thus, the porous MFI crystals obtained can be used for the preparation of effective bifunctional catalysts by the de position of a highly dispersed metallic (Pd) phase.

Zeolite catalysts for catalytic decomposition and reduction of NOx.

Jagielska E., Mostowicz R., Szarlik S., Mejsner J.

Prace Naukowe Instytutu Chemii i Technologii Nafty i Węgla Politechniki Wrocławskiej. Konferencje

2002

Vol. 10, nr 57

189-195

Catalytic decompostion and reduction of NOx by NH3 and CO in the presence of MFI zeolites and MFI zeolite containing catalysts was investigated. The catalyst activity was studied as a function of zeolite ion exchanged form (Na, H, Cu forms), type of an element introduced into zeolite framework, process temperature. Isomorphous substituted Fe, Co, Mn and mixed forms of these elements were used. Three types of catalysts were tested: a) pure zeolites, b) zeolites deposited on a-Al2O3 or cordierite, c) zeolite extrudates with g-Al2O3. [Fe]-MFI crystallized on a-Al2O3 used in the reduction of NOx by CO was the best catalyst. In the process of catalytic reduction of NOx by NH3 the best results were obtained in the presence of Na-[Fe]-MFI molecular sieve. In the process of NOx decomposition, the highest conversion values were obtained in the presence of Cu-[Al]-MFI and [Fe]-MFI.