Catalyst composition and catalytic reduction system

Abstract

A catalyst composition, a method of preparation of catalyst composition, a catalytic reduction system including the catalyst composition and a system using the catalytic reduction system are provided. The catalyst composition includes a templated amorphous metal oxide substrate, a catalyst material, and a sulfur scavenger material. The catalyst material includes a catalyst metal disposed on the templated metal oxide substrate and the sulfur scavenger includes an alkali metal.

1 . A catalyst composition, comprising:
 a templated amorphous metal oxide substrate having a plurality of pores;   a catalyst material comprising a catalyst metal and disposed on the substrate; and   a sulfur scavenger comprising an alkali metal and disposed on the substrate.   
     
     
         2 . The composition of  claim 1 , wherein the alkali metal comprises lithium, sodium, or potassium. 
     
     
         3 . The composition of  claim 2 , wherein the alkali metal comprises lithium. 
     
     
         4 . The composition of  claim 1 , wherein the alkali metal is in an amount from about 0.1 mole percent to about 15 mole percent of the substrate. 
     
     
         5 . The composition of  claim 4 , wherein the alkali metal is in an amount from about 3 mole percent to about 10 mole percent of the substrate. 
     
     
         6 . The composition of  claim 1 , wherein the catalyst metal comprises silver. 
     
     
         7 . The composition of  claim 1 , wherein the templated amorphous metal oxide substrate comprises alumina, silica, aluminosilicate, or combination thereof. 
     
     
         8 . The composition of  claim 1 , wherein the substrate further comprises a dopant material selected from the group consisting of zirconium, iron, gallium, indium, tungsten, zinc, platinum, and rhodium. 
     
     
         9 . The composition of  claim 1 , wherein the catalyst material and sulfur scavenger are dispersed in an intermixed form in the substrate. 
     
     
         10 . A method of preparation of a catalyst composition, comprising:
 combining a metal oxide precursor, a catalyst metal precursor and an alkali metal precursor in the presence of a templating agent;
 hydrolyzing and condensing to form an intermediate product that comprises metal oxide, alkali metal oxide, and catalyst metal; and 
   calcining to form a templated amorphous metal oxide substrate having a plurality of pores and comprising an alkali metal oxide and catalyst metal.   
     
     
         11 . A catalytic reduction system comprising:
 a catalyst support;   a catalyst composition disposed on the catalyst support, the catalyst composition comprising:   a templated amorphous metal oxide substrate having a plurality of pores;   a catalyst material comprising a catalyst metal and disposed on the substrate; and   a sulfur scavenger comprising an alkali metal and disposed on the substrate.   
     
     
         12 . The catalytic reduction system of  claim 11 , wherein the alkali metal comprises lithium. 
     
     
         13 . The catalytic reduction system of  claim 11 , wherein the alkali metal is in an amount from about 0.1 mole percent to about 15 mole percent based on the substrate. 
     
     
         14 . The catalytic reduction system of  claim 13 , wherein the alkali metal is in an amount from about 3 mole percent to about 10 mole percent based on the substrate. 
     
     
         15 . The catalytic reduction system of  claim 11 , wherein the catalyst metal comprises silver. 
     
     
         16 . A system comprising:
 an internal combustion engine, and   
       a catalytic reduction system disposed to receive an exhaust stream from the engine, wherein the catalytic reduction system comprises
 a catalyst support; 
 a catalyst composition disposed on the catalyst support, the catalyst composition comprising: 
 a templated amorphous metal oxide substrate having a plurality of pores; 
 a catalyst material comprising a catalyst metal and disposed on the substrate; and 
 a sulfur scavenger comprising an alkali metal and disposed on the substrate. 
 
     
     
         17 . A method of removing sulfur from a catalytic reduction system, comprising:
 passing an exhaust stream from an exhaust source over a catalyst composition, wherein the catalyst composition comprises a templated amorphous metal oxide substrate, a catalyst material comprising a catalyst metal, and a sulfur scavenger;   reacting the exhaust stream with the catalyst composition to form sulfates;   decomposing the sulfates to produce sulfur oxides; and   removing the sulfur oxides from the catalytic reduction system.   
     
     
         18 . The method of  claim 17 , wherein reacting the exhaust stream comprises reacting the exhaust stream with the sulfur scavenger of the catalyst composition to form the sulfates.