Exhaust gas purification catalyst, and exhaust gas purification filter and exhaust gas purification method using the same

Abstract

An exhaust gas purification catalyst includes: a support containing alumina as a major component; and an active species fine particle containing silver sulfate as a major component and having an average crystallite size of 3 nm to less than 100 nm, in which the active species fine particle is supported on a surface of the support.

What is claimed is: 
     
         1 . An exhaust gas purification catalyst comprising:
 a support containing alumina as a major component; and   an active species fine particle containing silver sulfate as a major component and having an average crystallite size of 3 nm to less than 100 nm, wherein   the active species fine particle is supported on a surface of the support.   
     
     
         2 . The exhaust gas purification catalyst according to  claim 1 , wherein
 a support amount of the silver sulfate with respect to a total amount of the support and the active species fine particle is 2 mass % to 50 mass % in terms of metal silver.   
     
     
         3 . The exhaust gas purification catalyst according to  claim 1 , wherein
 a specific surface area of the support is 5 m 2 /g to 300 m 2 /g.   
     
     
         4 . An exhaust gas purification filter comprising:
 an air-permeable substrate; and   the exhaust gas purification catalyst according to  claim 1  supported on the air-permeable substrate.   
     
     
         5 . An exhaust gas purification method comprising:
 oxidizing and removing particulate matter by bringing exhaust gas exhausted from an internal combustion engine into contact with the exhaust gas purification catalyst according to  claim 1 .