| 摘要 |
<p>PURPOSE:To effectively prevent the deactivation of Rh by incorporating ultrafine powder of zirconia having average particle diameter not more than 5,000Angstrom at 10-50wt.% into an alumina layer which is provided on the surface of a carrier and contains at least Rh as an catalytic component. CONSTITUTION:Ultrafine powder of zirconia having average particle diameter not more than 5,000Angstrom is added to a rhodium aq. soln. and mixed therewith and this mixture is heat-treated to make rhodium to be carried by zirconia particles. Then the zirconia particles are added to alumina slurry and mixed therewith and a catalytic carrier is immersed into the obtained alumina slurry and calcined. A catalyst for purifying exhaust gas wherein an alumina layer incorporated with 10-50% ultrafine particles of zirconia is formed on the surface of the catalytic carrier is prepared by such a way. For example, a first alumina layer 2 contg. platinum and ceria is formed on the surface of a honeycomb-type catalytic carrier 1 made of cordierite. Then the catalyst for purifying exhaust gas prevented from deactivating rhodium is obtained by giving an overcoating of a second alumina layer 3 contg. 10-50wt.% zirconia having average particle diameter not more than 5,00Angstrom and rhodium to the first alumina layer 2.</p> |
