CATALYST SUPPORT COMPOSITION FOR ACCUMULATION OF NITROGEN OXIDES

文件类型：PDF文档
文件大小：850K
FIELD : chemical or physical processes. SUBSTANCE : present invention relates to a method of producing a carrier material composition for use in a catalyst for treating exhaust gases in order to reduce content of NOx. Method includes the following steps : i) preparing an aqueous suspension of a precursor of mixed oxide Mg/AI; ii) preparing an aqueous solution of a cerium salt; iii) preparing an aqueous solution of a salt or salts of one or more rare-earth elements other than cerium salts; iv) combining, in any order, at least the aqueous suspension from step i) with the aqueous solution from step ii) and the aqueous solution from step iii) to obtain an aqueous mixture; v) drying the aqueous mixture to obtain a dried granular material and vi) calcining the dried granular material, wherein the content of salts of one or more rare-earth elements, different from cerium, is in range of 5 wt. % up to 50 wt. %, in terms of the sum of weights of cerium salts from the aqueous solution from step ii) and salts of rare-earth elements different from cerium salts from the aqueous solution from step iii), wherein the weight of all salts is converted to the weight of their oxides. Obtained composition contains two phases : a first phase containing a mixed oxide Mg/Al, and a second phase, containing a cerium oxide and an oxide based on a rare earth element (or elements), different from cerium oxide, wherein the second phase is a solid solution. Invention also relates to versions of a carrier material composition and to use of the carrier material composition as a component for accumulating nitrogen oxides in a catalyst for treating exhaust gases. EFFECT : present invention enables to provide a method of producing a composition of a carrier material and a composition of a carrier material, which could be used in NOx accumulation catalysts with high thermal stability and high ability to accumulate nitrogen oxides, in particular at high temperatures. 16 cl, 1 dwg, 2 tbl, 7 ex