| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a hydrocarbon adsorbing material for exhaust gas, which has excellent acid-resistant characteristics, hydrophobicity and heat resistance, has high capacity for holding the adsorbed hydrocarbon and can delay the desorption of the hydrocarbon (cold HC) discharged when an engine is started and to provide an exhaust gas purifying catalyst in which the hydrocarbon adsorbing material is used and which has excellent cold HC purifying performance. <P>SOLUTION: This hydrocarbon adsorbing material is acid BETA zeolite in which a part or all of Al atoms or Si atoms are substituted by other metal atoms, acid NU-2 zeolite having the same BEA structure as that of the acid BETA zeolite or the zeolite which has the BEA structure resembled to that of the acid BETA zeolite and is obtained by using SSZ-31 and/or SSZ-41 as a precursor. <P>COPYRIGHT: (C)2004,JPO |
