| 摘要 |
PROBLEM TO BE SOLVED: To further improve an initial NOx purification capacity by a method in which an ultra-hydrophilic photocatalyst layer is formed on the surface of a honeycomb support backing, a catalyst supporting layer is formed from a porous support on the surface of the layer, a catalyst metal and a NOx- occluding material is supported on the layer, and the material is supported mainly in the surface layer of the catalyst supporting layer. SOLUTION: An exhaust gas purification catalyst is composed of a monolithic (honeycomb) support backing 1, a titanium oxide layer (ultra-hydrophilic photocatalyst layer) 2 formed on the cell-wall surface of the backing 1, and an alumina layer (catalyst supporting layer) 3 formed on the surface of the layer 2. On the layer 3 are supported Pt and Rh as a catalyst metal and Ba and Li as a NOx occluding material. Here, the NOx occluding material is supported mainly on the surface layer of the alumina layer 3. By this method, the probability of contact between a reducing component of exhaust gas and SOx occluded as sulfate in the Nox occluding material in the depths can improve. |
