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US 4,274,981 AGranted
Catalyst for purifying exhaust gas and the process for manufacturing thereof
AssigneeToyota Jidosha Kogyo Kabushiki Kaisha
InventorsYoshihiro Suzuki, Hiroo Kinoshita, Naomi Akasaka
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Abstract
A catalyst for purifying exhaust gas composed of a catalyst carrier coated with a metal oxide material containing a spinel metal oxide of the formula: MAl.sub.2 O.sub.4 wherein M is Sr, Mg, Cu, Mn, Mo, Zn, Fe, Co or Ni the metal oxide coated carrier further being coated with rhodium and platinum and/or palladium as catalytically active components. The catalytically active components also can include cerium.
Claims7
A catalyst for purifying exhaust gas comprising:
- a catalyst carrier coated with a metal oxide material containing a spinel metal oxide of the formula:
- MAl.sub.2 O.sub.4 wherein M is Sr, Cu, Mn, Mo, Zn, Fe, Co or Ni, said metal oxide coated carrier further being coated with Rh and Ce and Pt and/or Pd as the catalytically active components.
A process for manufacturing a catalyst for purifying exhaust gas, comprising:
- treating a spinel metal oxide of the formula MAl.sub.2 O.sub.4, wherein M is Sr, Cu, Mn, Mo, Zn, Fe, Co or Ni, with an inorganic or organic acid;
- immersing a catalyst carrier in a slurry consisting of said treated spinel oxide and alumina sol stabilized with inorganic or organic acid, thereby forming a film comprising said spinel metal oxide on the surface of said carrier;
- washing said film coated carrier with water;
- drying and calcining said film coated carrier;
- immersing said calcined carrier in a solution containing a soluble form of Pt and/or Pd followed by the immersion of said carrier in a solution containing a soluble form of Rh;
- and
- calcining or reducing said noble metal coated carrier.
4 more elements
Dependencies are inferred from the claim text.