| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an oxygen occluding agent and a catalyst for cleaning an exhaust gas in which a catalyst metal is made to expose on pore surfaces and an exhaust gas is made to diffuse inside the oxygen occluding agent by dispersing a large number of fine pores as the oxygen occluding agent contact frequency of the catalyst metal with the exhaust gas is increased, can enhance the cleaning performance of the exhaust gas. <P>SOLUTION: When a composite oxide containing a catalyst metal (Rh), Ce and Zr is prepared, by preparing a precursor through adding a template material (casting material), the catalyst metal (Rh) is placed at a crystal lattice or between crystal points, and the average pore diameter of the composite oxide is 5 nm or smaller and the ratio of the pore volume of the pores of the pore diameter of 5 nm or smaller holding in the pore volume of the pores of the pore diameter of 100 nm is 70% or more. the oxygen occluding performance is increased by Rh, the diffusivity inside of composite oxide of the exhaust gas is enhanced and the catalyst metal is largely exposed on the surfaces of the pores of the composite oxide; thereby, the exhaust gas cleaning performance is enhanced. <P>COPYRIGHT: (C)2007,JPO&INPIT |
