Ferrite as three-way catalyst for treatment of exhaust gas from vehicle engine

Abstract

A kind of ferrite used as a three-way catalyst for treatment of exhaust gas from vehicle engines is revealed. Mono-nitrogen oxides (NO X ), carbon monoxide (CO) and hydrocarbons (HC) in exhaust gas from vehicle engines can be removed effectively by the three-way catalyst made from ferrite containing at least one substitutional metal.

What is claimed is: 
     
         1 . A method for treating exhaust gas from vehicle engines by ferrite, comprising applying the ferrite used as a three-way catalyst to the exhaust gas from vehicle engines for removal of mono-nitrogen oxides (NO X ), carbon monoxide (CO) and hydrocarbons (HC). 
     
     
         2 . The method as claimed in  claim 1 , wherein the ferrite comprises iron and at least one substitutional metal selected from the group consisting of copper (Cu), manganese (Mn), titanium (Ti), cobalt (Co), zinc (Zn), nickel (Ni), strontium (Sr), calcium (Ca), magnesium (Mg), chromium (Cr), aluminum (Al), neodymium (Nd), samarium (Sm), lanthanum (La), and cerium (Ce), and their combinations; and wherein a molar ratio of the substitutional metal to the iron is ranging from 1:0.5 to 1:10. 
     
     
         3 . The method as claimed in  claim 1 , wherein the carbon monoxide (CO) and the hydrocarbons (HC) in exhaust gas are used as reductants for removal of the mono-nitrogen oxides (NO X ) in exhaust gas from gasoline engines. 
     
     
         4 . The method as claimed in  claim 1 , wherein urea solution, ammonia, hydrogen or other selective reductant is added for removal of the mono-nitrogen oxides (NO X ) in exhaust gas from diesel engines. 
     
     
         5 . The method as claimed in  claim 1 , wherein the ferrite is produced into a honeycomb catalyst. 
     
     
         6 . The method as claimed in  claim 5 , wherein the honeycomb catalyst is used as a three-way catalytic converter for treating exhaust gas from gasoline engines. 
     
     
         7 . The method as claimed in  claim 5 , wherein the honeycomb catalyst is used as a three-way catalytic converter for treating exhaust gas from diesel engines.