Particulate combustion catalyst, particulate filter and exhaust gas purifying apparatus

Abstract

Provided is a particulate combustion catalyst including a carrier formed of Zr oxide, a carrier formed of a Zr—Ce composite oxide, or a carrier formed of a composite oxide containing Zr, Ce, and at least one metal selected from among Nd, La, Fe, Y, Pr, Ba, Ca, Mg, Sn, and Sr; an oxide of at least one metal selected from the group consisting of Ba, Ca, Mg, and Sr, the metal oxide being supported on the carrier in an amount, as reduced to metal, of 0.5 to 30 mass % with respect to the carrier; and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier. Also provided are a particulate filter coated with the catalyst; and an exhaust gas cleaning apparatus including a particulate filter coated with the catalyst.

1 . A particulate combustion catalyst characterized by comprising a carrier formed of zirconium oxide; an oxide of at least one metal selected from the group consisting of Ba, Ca, Mg, and Sr, the metal oxide being supported on the carrier in an amount, as reduced to metal, of 0.5 to 30 mass % with respect to the carrier; and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier. 
     
     
         2 . A particulate combustion catalyst characterized by comprising a carrier formed of a zirconium-cerium composite oxide; an oxide of at least one metal selected from the group consisting of Ba, Ca, Mg, and Sr, the metal oxide being supported on the carrier in an amount, as reduced to metal, of 0.5 to 30 mass % with respect to the carrier; and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier. 
     
     
         3 . A particulate combustion catalyst characterized by comprising a carrier formed of a composite oxide containing zirconium, cerium, and at least one metal selected from among Nd, La, Fe, Y, Pr, Ba, Ca, Mg, Sn, and Sr; an oxide of at least one metal selected from the group consisting of Ba, Ca, Mg, and Sr, the metal oxide being supported on the carrier in an amount, as reduced to metal, of 0.5 to 30 mass % with respect to the carrier; and metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier. 
     
     
         4 . A particulate combustion catalyst according to  claim 1 , wherein the amount, as reduced to metal, of metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, is 0.1 to 25 mass % on the basis of the total mass of the carrier and an oxide of at least one metal selected from the group consisting of Ba, Ca, Mg, and Sr. 
     
     
         5 . A particulate combustion catalyst according to  claim 1 , wherein the surface of the carrier is provided with SiO 2 , TiO 2 , ZrO 2 , or Al 2 O 3 , which serves as a binder component. 
     
     
         6 . A particulate filter characterized by being coated with a particulate combustion catalyst as recited in  claim 1 . 
     
     
         7 . An exhaust gas cleaning apparatus characterized by comprising a particulate filter coated with a particulate combustion catalyst as recited in  claim 1 . 
     
     
         8 . A particulate combustion catalyst according to  claim 2 , wherein the amount, as reduced to metal, of metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, is 0.1 to 25 mass % on the basis of the total mass of the carrier and an oxide of at least one metal selected from the group consisting of Ba, Ca, Mg, and Sr. 
     
     
         9 . A particulate combustion catalyst according to  claim 3 , wherein the amount, as reduced to metal, of metallic Ag or Ag oxide, which serves as a catalyst component and is supported on the carrier, is 0.1 to 25 mass % on the basis of the total mass of the carrier and an oxide of at least one metal selected from the group consisting of Ba, Ca, Mg, and Sr. 
     
     
         10 . A particulate combustion catalyst according to  claim 2 , wherein the surface of the carrier is provided with SiO 2 , TiO 2 , ZrO 2 , or Al 2 O 2 , which serves as a binder component. 
     
     
         11 . A particulate combustion catalyst according to  claim 3 , wherein the surface of the carrier is provided with SiO 2 , TiO 2 , ZrO 2 , or Al 2 O 2 , which serves as a binder component. 
     
     
         12 . A particulate combustion catalyst according to  claim 4 , wherein the surface of the carrier is provided with SiO 2 , TiO 2 , ZrO 2 , or Al 2 O 2 , which serves as a binder component. 
     
     
         13 . A particulate combustion catalyst according to  claim 8 , wherein the surface of the carrier is provided with SiO 2 , TiO 2 , ZrO 2 , or Al 2 O 2 , which serves as a binder component. 
     
     
         14 . A particulate combustion catalyst according to  claim 9 , wherein the surface of the carrier is provided with SiO 2 , TiO 2 , ZrO 2 , or Al 2 O 2 , which serves as a binder component. 
     
     
         15 . A particulate filter characterized by being coated with a particulate combustion catalyst as recited in  claim 2 . 
     
     
         16 . A particulate filter characterized by being coated with a particulate combustion catalyst as recited in  claim 3 . 
     
     
         17 . An exhaust gas cleaning apparatus characterized by comprising a particulate filter coated with a particulate combustion catalyst as recited in  claim 2 . 
     
     
         18 . An exhaust gas cleaning apparatus characterized by comprising a particulate filter coated with a particulate combustion catalyst as recited in  claim 3 .