Patent ID: 6027703
Filing Date: 2000-02-22
Classification: B01D,B01J,F01N,Y02T

Abstract:
A method of purifying a pollutant-containing exhaust gas from a gasoline engine comprising the steps of:contacting a pollutant-containing gas stream with a body of porous, catalytic material having a predetermined low response temperature above which it is catalytically reduces pollutants;storing hydrocarbons present in the gas stream in the porous body at a temperature below the response temperature;releasing said stored hydrocarbons when the temperature exceeds the response temperature and reducing the pollutants with a reducing agent comprising hydrocarbons, carbon monoxide or mixtures thereof,wherein said catalytic material comprises a spinel of the formula A1.sub.a1(1-x) A2.sub.a2(1-x) Al.sub.b O.sub.4 with a1+a2+b.ltoreq.3 and a1, a2 and b are greater than 0, and 0.ltoreq.x<1, and A1 and A2 are independently selected from the group consisting of Mg, Ca, Mn, Fe, Ni, Co, Cu, Sn and Ti, andwherein the response temperature is below 150.degree. C.