Three-way catalytic converter using nanoparticles

Abstract

The present disclosure relates to a substrate comprising nanomaterials for treatment of gases, washcoats for use in preparing such a substrate, and methods of preparation of the nanomaterials and the substrate comprising the nanomaterials. More specifically, the present disclosure relates to a substrate comprising nanomaterial for three-way catalytic converters for treatment of exhaust gases.

1 . A coated substrate comprising:
 a first washcoat layer comprising oxidative catalytically active particles, the oxidative catalytically active particles comprising oxidative composite nanoparticles bonded to first micron-sized carrier particles, wherein the oxidative composite nanoparticles comprise a first support nanoparticle and one or more oxidative catalyst nanoparticles; and   a second washcoat layer comprising reductive catalytically active particles, the reductive catalytically active particles comprising reductive composite nanoparticles bonded to second micron-sized carrier particles, wherein the reductive composite nanoparticles comprise a second support nanoparticle and one or more reductive catalyst nanoparticles:   wherein the first washcoat layer is disposed underneath the second washcoat layer.   
     
     
         2 - 3 . (canceled) 
     
     
         4 . The coated substrate of  claim 1 , wherein the oxidative catalyst nanoparticles comprise platinum, palladium, or a mixture thereof. 
     
     
         5 . The coated substrate of  claim 4 , wherein the oxidative catalyst nanoparticles comprise palladium. 
     
     
         6 . The coated substrate of  claim 1 , wherein the first support nanoparticles comprise aluminum oxide. 
     
     
         7 . The coated substrate of  claim 1 , wherein the first micron-sized carrier particles comprise aluminum oxide. 
     
     
         8 . The coated substrate of  claim 1 , wherein the first micron-sized carrier particle is pre-treated at a temperature range of about 700° C. to about 1500° C. 
     
     
         9 . The coated substrate of  claim 1 , wherein the reductive catalyst nanoparticles comprise rhodium. 
     
     
         10 . The coated substrate of  claim 1 , wherein the second support nanoparticles comprise cerium zirconium oxide. 
     
     
         11 . The coated substrate of  claim 1 , wherein the second micron-sized carrier particles comprise cerium zirconium oxide. 
     
     
         12 . The coated substrate of  claim 1 , wherein the support nanoparticles have an average diameter of 10 nm to 20 nm. 
     
     
         13 . The coated substrate of  claim 1 , wherein the catalytic nanoparticles have an average diameter of between 1 nm and 5 nm. 
     
     
         14 . The coated substrate of  claim 1 , further comprising an oxygen storage component. 
     
     
         15 . The coated substrate of  claim 14 , wherein the oxygen storage component is cerium zirconium oxide or cerium oxide. 
     
     
         16 . The coated substrate of  claim 1 , further comprising a NOx absorber component. 
     
     
         17 . The coated substrate of  claim 16 , wherein the NOx absorber component is nano-sized BaO. 
     
     
         18 . The coated substrate of  claim 16 , wherein the NOx absorber component is micron-sized BaO. 
     
     
         19 . The coated substrate of  claim 1 , wherein the substrate comprises cordierite. 
     
     
         20 . The coated substrate of  claim 1 , wherein the substrate comprises a grid array structure. 
     
     
         21 . The coated substrate of  claim 1 , wherein:
 the coated substrate has a platinum group metal loading of 4 g/l or less and a light-off temperature for carbon monoxide at least 5° C. lower than the light-off temperature of a substrate with the same platinum group metal loading deposited by wet-chemistry methods;   the coated substrate has a platinum group metal loading of 4 g/l or less and a light-off temperature for hydrocarbon at least 5° C. lower than the light-off temperature of a substrate with the same platinum group metal loading deposited by wet-chemistry methods; or   the coated substrate has a platinum group metal loading of 4 g/l or less and a light-off temperature for nitrogen oxide at least 5° C. lower than the light-off temperature of a substrate with the same platinum group metal loading deposited by wet-chemistry methods.   
     
     
         22 - 23 . (canceled) 
     
     
         24 . The coated substrate of  claim 1 , wherein the coated substrate has a platinum group metal loading of about 3.0 g/l to about 4.0 g/l. 
     
     
         25 . The coated substrate of  claim 1 , wherein said coated substrate has a platinum group metal loading of about 3.0 g/l to about 4.0 g/l, and after 125,000 miles of operation in a vehicular catalytic converter, the coated substrate has a light-off temperature for carbon monoxide at least 5° C. lower than a coated substrate prepared by depositing platinum group metals by wet chemical methods having the same platinum group metal loading after 125,000 miles of operation in a vehicular catalytic converter. 
     
     
         26 . The coated substrate of  claim 1 , wherein a ratio of oxidative catalytically active particles to reductive catalytically active particles is between 6:1 and 40:1. 
     
     
         27 . A catalytic converter comprising a coated substrate of  claim 1 . 
     
     
         28 . An exhaust treatment system comprising a conduit for exhaust gas and a catalytic converter comprising a coated substrate of  claim 1 . 
     
     
         29 . A vehicle comprising a catalytic converter according to  claim 27 . 
     
     
         30 . A method of treating an exhaust gas, comprising contacting the coated substrate of  claim 1  with the exhaust gas. 
     
     
         31 . (canceled) 
     
     
         32 . A method of forming a coated substrate, the method comprising:
 a) coating a substrate with a first washcoat composition comprising oxidative catalytically active particles wherein the oxidative catalytically active particles comprise oxidative composite nanoparticles bonded to first micron-sized carrier particles, and wherein the oxidative composite nanoparticles comprise a first support nanoparticle and one or more oxidative catalyst nanoparticles; and   b) coating the substrate with a second washcoat composition comprising reductive catalytically active particles wherein the reductive catalytically active particles comprise reductive composite nanoparticles bonded to second micron-sized carrier particles, and wherein the reductive composite nanoparticles comprise a second support nanoparticle and one or more reductive catalyst nanoparticles;   wherein the first washcoat composition is coated onto the substrate prior to the second washcoat composition.   
     
     
         33 - 34 . (canceled) 
     
     
         35 . A coated substrate comprising:
 a first washcoat layer comprising oxidative catalytically active particles, the oxidative catalytically active particles comprising oxidative composite nanoparticles bonded to first micron-sized carrier particles, wherein the oxidative composite nanoparticles comprise a first support nanoparticle and one or more oxidative catalyst nanoparticles; and   a second washcoat layer comprising reductive catalytically active particles, the reductive catalytically active particles comprising reductive composite nanoparticles bonded to second micron-sized carrier particles, wherein the reductive composite nanoparticles comprise a second support nanoparticle and one or more reductive catalyst nanoparticles:   wherein the second washcoat layer is disposed underneath the first washcoat layer.   
     
     
         36 . The coated substrate of  claim 35 , wherein the oxidative catalyst nanoparticles comprise platinum, palladium, or a mixture thereof. 
     
     
         37 . The coated substrate of  claim 36 , wherein the oxidative catalyst nanoparticles comprise palladium. 
     
     
         38 . The coated substrate of  claim 35 , wherein the first support nanoparticles comprise aluminum oxide. 
     
     
         39 . The coated substrate of  claim 35 , wherein the first micron-sized carrier particles comprise aluminum oxide. 
     
     
         40 . The coated substrate of  claim 35 , wherein the first micron-sized carrier particle is pre-treated at a temperature range of about 700° C. to about 1500° C. 
     
     
         41 . The coated substrate of  claim 35 , wherein the reductive catalyst nanoparticles comprise rhodium. 
     
     
         42 . The coated substrate of  claim 35 , wherein the second support nanoparticles comprise cerium zirconium oxide. 
     
     
         43 . The coated substrate of  claim 35 , wherein the second micron-sized carrier particles comprise cerium zirconium oxide. 
     
     
         44 . The coated substrate of  claim 35 , wherein the support nanoparticles have an average diameter of 10 nm to 20 nm. 
     
     
         45 . The coated substrate of  claim 35 , wherein the catalytic nanoparticles have an average diameter of between 1 nm and 5 nm. 
     
     
         46 . The coated substrate of  claim 35 , further comprising an oxygen storage component. 
     
     
         47 . The coated substrate of  claim 46 , wherein the oxygen storage component is cerium zirconium oxide or cerium oxide. 
     
     
         48 . The coated substrate of  claim 35 , further comprising a NOx absorber component. 
     
     
         49 . The coated substrate of  claim 48 , wherein the NOx absorber component is nano-sized BaO. 
     
     
         50 . The coated substrate of  claim 48 , wherein the NOx absorber component is micron-sized BaO. 
     
     
         51 . The coated substrate of  claim 35 , wherein the substrate comprises cordierite. 
     
     
         52 . The coated substrate of  claim 35 , wherein the substrate comprises a grid array structure. 
     
     
         53 . The coated substrate of  claim 35 , wherein:
 the coated substrate has a platinum group metal loading of 4 g/l or less and a light-off temperature for carbon monoxide at least 5° C. lower than the light-off temperature of a substrate with the same platinum group metal loading deposited by wet-chemistry methods;   the coated substrate has a platinum group metal loading of 4 g/l or less and a light-off temperature for hydrocarbon at least 5° C. lower than the light-off temperature of a substrate with the same platinum group metal loading deposited by wet-chemistry methods; or;   the coated substrate has a platinum group metal loading of 4 g/l or less and a light-off temperature for nitrogen oxide at least 5° C. lower than the light-off temperature of a substrate with the same platinum group metal loading deposited by wet-chemistry methods.   
     
     
         54 . The coated substrate of  claim 35 , wherein the coated substrate has a platinum group metal loading of about 3.0 g/l to about 4.0 g/l. 
     
     
         55 . The coated substrate of  claim 35 , wherein said coated substrate has a platinum group metal loading of about 3.0 g/l to about 4.0 g/l, and after 125,000 miles of operation in a vehicular catalytic converter, the coated substrate has a light-off temperature for carbon monoxide at least 5° C. lower than a coated substrate prepared by depositing platinum group metals by wet chemical methods having the same platinum group metal loading after 125,000 miles of operation in a vehicular catalytic converter. 
     
     
         56 . The coated substrate of  claim 35 , wherein a ratio of oxidative catalytically active particles to reductive catalytically active particles is between 6:1 and 40:1. 
     
     
         57 . A catalytic converter comprising a coated substrate of  claim 35 . 
     
     
         58 . An exhaust treatment system comprising a conduit for exhaust gas and a catalytic converter comprising a coated substrate of  claim 35 . 
     
     
         59 . A vehicle comprising a catalytic converter according to  claim 57 . 
     
     
         60 . A method of treating an exhaust gas, comprising contacting the coated substrate of  claim 35  with the exhaust gas. 
     
     
         61 . A method of forming a coated substrate, the method comprising:
 a) coating a substrate with a first washcoat composition comprising oxidative catalytically active particles, wherein the oxidative catalytically active particles comprise oxidative composite nanoparticles bonded to first micron-sized carrier particles, and wherein the oxidative composite nanoparticles comprise a first support nanoparticle and one or more oxidative catalyst nanoparticles; and   b) coating the substrate with a second washcoat composition comprising reductive catalytically active particles, wherein the reductive catalytically active particles comprise reductive composite nanoparticles bonded to second micron-sized carrier particles, and wherein the reductive composite nanoparticles comprise a second support nanoparticle and one or more reductive catalyst nanoparticles;   wherein the second washcoat composition is coated onto the substrate prior to the first washcoat composition.