Novel scr catalysts and after-treatment devices for diesel engine exhaust gas

Abstract

Disclosed is an SCR catalyst composition having improved NOx conversion and a device for post-treating diesel engine exhaust gas using the same. The SCR catalyst composition can effectively convert NOx generated from an engine into harmless components. The device, which improves the NOx conversion, includes an SCR catalyst module disposed downstream of a diesel engine and having an injector, an oxidation catalyst module disposed downstream of the SCR catalyst module, and a catalyst soot filter module, all of which are successively arranged in series.

1 . A device for emitting diesel engine exhaust gas, suitable for improving NO x  conversion, comprising an SCR catalyst module disposed downstream of a diesel engine and including an injector, an oxidation catalyst module disposed downstream of the SCR catalyst module, and a catalyst soot filter module, all of which are successively arranged in series. 
     
     
         2 . The device according to  claim 1 , wherein an SCR catalyst used in the SCR catalyst module comprises Cu or Fe-containing zeolite impregnated with one or a combination of two selected from the group consisting of Pt, Pd and Rh; or Cu, Fe or Si-containing alumina impregnated with one or a combination of two selected from the group consisting of Pt, Pd and Rh. 
     
     
         3 . The device according to  claim 2 , wherein the catalyst is applied on a carrier made of a ceramic or a fireproof metal including stainless steel. 
     
     
         4 . The device according to  claim 2 , wherein the SCR catalyst comprises 5˜10 wt % Cu or Fe-containing zeolite impregnated with 0.5 wt % or less of one or more selected from the group consisting of Pt, Pd and Rh. 
     
     
         5 . The device according to  claim 2 , wherein the SCR catalyst comprises 5˜10 wt % Cu, Fe or Si-containing alumina impregnated with 0.5 wt % or less of one or more selected from the group consisting of Pt, Pd and Rh.