| 摘要 |
<p>A method of catalytic reduction of nitrogen oxides involving supplying and burning a fuel under the periodical rich/lean condition described in the specification, and contacting the resultant exhaust gas with a catalyst, to thereby catalytically reduce nitrogen oxides in the exhaust gas, characterized in that the catalyst comprises: (A) a first catalyst component comprising (a) a ceria or (b) a praseodymium oxide or (c) at lest one selected from a mixture of oxides of at least two elements selected from among cerium, zirconium, praseodymium, neodymium, terbium, samarium, gadolinium and lanthanum, and a composite oxide of at lest two of these elements, and (B) a second catalyst composition comprising at least one selected from among platinum, rhodium, palladium, a platinum oxide, a rhodium oxide and a palladium oxide; an above catalyst; and a catalyst structure for use in the catalytic reduction of NOx which comprises an inert substrate and the above catalyst provided on the substrate as a catalyst layer.</p> |
