(19)
(11)EP 1 074 289 A3

(12)EUROPEAN PATENT APPLICATION

(88)Date of publication A3:
10.10.2001 Bulletin 2001/41

(43)Date of publication A2:
07.02.2001 Bulletin 2001/06

(21)Application number: 00115164.6

(22)Date of filing:  12.07.2000
(51)Int. Cl.7B01D 53/94, B01J 37/025, B01J 29/068, B01J 35/04
(84)Designated Contracting States:
AT BE CH CY DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV MK RO SI

(30)Priority: 06.08.1999 JP 22460099
06.07.2000 JP 2000205381

(71)Applicant: NISSAN MOTOR CO., LTD.
Yokohama-shi Kanagawa-ken (JP)

(72)Inventors:
  • Yamamoto, Shinji
    Yokosuka-shi, Kanagawa-ken (JP)
  • Takaya, Masahiro
    Yokosuka-shi, Kanagawa-ken (JP)

(74)Representative: Weber, Joachim, Dr. 
Hoefer, Schmitz, Weber & Partner Patentanwälte Gabriel-Max-Strasse 29
81545 München
81545 München (DE)

  


(54)Exhaust gas purifying catalyst and process for preparing the catalyst


(57) An exhaust gas purifying catalyst comprises a hydrocarbon adsorbent layer and a metal-based catalyst layer on a monolithic support. The catalyst contains zeolite in the underlying hydrocarbon adsorbent layer and contains noble metals such as palladium, platinum, rhodium, etc. in the overlying metal-based catalyst layer. Also, both layers contain an alkaline metal, etc., and a weight ratio of the alkaline metal, etc. contained in the metal-based catalyst layer to the alkaline metal, etc. contained in the hydrocarbon adsorbent layer is set to 60:40 to 99:1. A process for preparing the above catalyst comprises forming the metal-based catalyst by coating slurry. The slurry contains water insoluble or water hardly-soluble alkaline metal and/or alkaline earth metal compound.