To obtain a NOX-occlusion reduction-type catalyst excellent in NOX- occlusion performance by uniformly supporting a noble metal in a high dispersion state into an area from the surface to the inside of a coating layer.
The noble metal is supported in the coating layer by bringing a solution containing a dissolved noble metal compound into contact with the coating layer in the supercritical state or the subcritical state. Or, after supporting the noble metal compound in the coating layer, the coating layer is treated in the supercritical atmosphere or the subcritical atmosphere. It is considered that the noble metal is conveyed by a supercritical fluid or a subcritical fluid and diffuses in the coating layer. Thereby, it becomes possible to uniformly support the noble metal in the coating layer.
ITAHARA HIROSHI
TAKAHASHI NAOKI
FUKUSHIMA YOSHIAKI
SUGIURA MASAHIRO
