Device for the Purification of Exhaust Gases from a Heat Engine, Comprising a Ceramic Carrier and an Active Phase Mechanically Anchored in the Carrier

Abstract

Device for the purification of exhaust gases from a thermal combustion engine comprising: one or several ceramic catalyst carriers comprising an arrangement of crystallites of the same size, same isodiametric morphology and same chemical composition, or approximately the same size, same isodiametric morphology and same chemical composition in which each crystallite is in point or quasi-point contact with the surrounding crystallites, and one or several active phases for chemical destruction of impurities in the exhaust gas comprising metallic particles mechanically anchored in said catalyst carrier such that coalescence and mobility of each particle are limited to a maximum volume corresponding to the volume of a crystallite of said ceramic catalyst carrier.

1 - 8 . (canceled) 
     
     
         9 . A device for the purification of exhaust gases from a thermal combustion engine comprising:
 one or several ceramic catalyst carriers comprising an arrangement of crystallites of the same size, same isodiametric morphology and same chemical composition, or approximately the same size, same isodiametric morphology and same chemical composition in which each crystallite is in point or quasi-point contact with the surrounding crystallites; the average equivalent diameter of said crystallites being between 2 and 20 nm; and   one or several active phases for chemical destruction of impurities in the exhaust gas comprising metallic particles mechanically anchored in said catalyst carrier such that coalescence and mobility of each particle are limited to a maximum volume corresponding to the volume of a crystallite of said ceramic catalyst carrier; the average equivalent diameter of said metallic particles being between 2 and 20 nm.   
     
     
         10 . The device of  claim 9 , wherein the arrangement is made of a material selected from the group consisting of: i) alumina (Al 2 O 3 ) or ceria (CeO 2 ) optionally stabilised with gadolinium oxide; ii) zirconia (ZrO 2 ) optionally stabilised with yttrium oxide or spinel phase; iii) lanthanum oxide (La 2 O 3 ); and mixtures thereof. 
     
     
         11 . The device of  claim 9 , wherein the metallic particles are chosen from among:
 (i) noble metals selected from the group consisting of Ruthenium, Rhodium, Palladium, Osmium, Iridium, Platinum, and an alloy of one to three thereof;   (ii) transition metals selected from the group consisting of Nickel, Silver, Gold, Cobalt, Copper, and an alloy of one to three thereof; and   (iii) an alloy of one to three of the noble metals and one to three of the transition metals.   
     
     
         12 . The device of  claim 9 , wherein the average equivalent diameter of crystallites is between 5 and 15 nm, and the average equivalent diameter of metallic particles is less than 10 nm. 
     
     
         13 . The device of  claim 9 , wherein the arrangement of crystallites is optimally a compact hexagonal or face-centred cubic stack in which each crystallite is in point or quasi-point contact with not more than 12 other crystallites within a 3-dimensional space. 
     
     
         14 . A method for purification of exhaust gases from a thermal combustion engine, comprising circulating exhaust gases through the device of  claim 9 . 
     
     
         15 . The method of  claim 14 , wherein the thermal combustion engine is an automobile vehicle engine. 
     
     
         16 . The method of  claim 15 , wherein the automobile vehicle engine is a diesel engine. 
     
     
         17 . The method of  claim 15 , wherein the thermal combustion engine is a gasoline engine.