Zrox, ce-zrox, ce-zr-reox as host matrices for redox active cations for low temperature, hydrothermally durable and poison resistant scr catalysts
AssigneeUmicore AG & Co. KG
InventorsBarry W. L. SOUTHWARD, John G. Nunan
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Abstract
The present invention relates to application of catalysts for the Selective Catalytic Reduction of oxides of Nitrogen using N-containing reductant. The catalysts are characterised as phase pure lattice oxide materials into which catalytically active cations are incorporated at high levels of dispersion such that conventional analysis reveals a highly phase pure material. The materials are further characterised by high activity, hydrothermal durability and poison tolerance in the intended application.
Claims40
A method for the conversion of the oxides of nitrogen to nitrogen by contacting said nitrogen oxides with a nitrogen-containing reductant in the presence of a base metal oxide catalyst comprising:
- (a) a phase pure crystal lattice structure, and
- (b) catalytically active cations dispersed within said lattice structure
A method for making a catalytically active cation doped lattice as a catalyst comprising incorporating a phase pure crystal lattice structure with catalytically active cations without the formation of additional phases, such that phase analysis by conventional x-ray diffraction method reveals a substantially phase pure material (>95%), with bulk metal oxide dopant phase being recorded at <5% and dopant metal oxide particle size, as determined by line-broadening/Scherrer equation determination, is about 30 Å to about 100 Å.
A heterogeneous base metal catalyst, with optional low zeolite/zeotype content with said catalyst consisting of:
- (a) a phase pure crystal lattice structure, wherein the lattice structure is selected from one or a mixture of oxides based upon zirconium, cerium-zirconium composite, cerium-zirconium-yttrium composite, cerium-zirconium-rare earth composite or cerium-zirconium-yttrium-rare earth composite, and
- (b) catalytically active cations dispersed with said lattice structure, wherein the catalytically dispersed cations are selected from the group consisting of the transition metal series, alkaline earth metal group, alkali metal group of the Periodic Table of Elements and mixtures thereof.
Dependencies are inferred from the claim text.