# US 7,410,626 B2 · Layered ammonia oxidation catalyst > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,410,626 B2 - Document ID: US7410626B2 - Status: Granted - Kind: B2 - Application number: 10/659,159 - Filed: 2003-09-10 - Published: 2005-03-10 - Granted: 2008-08-12 - Earliest claimed: 2003-09-10 - Assignees: BASF Catalysts LLC - Inventors: Pascaline Harrison Tran; James Mon-Her Chen; Gerard Diomede Lapadula; Marc Thomas Blute - Web page: https://patentgrep.com/patent/US7410626B2 ## CPC - B01D 53/8634: {Ammonia} - B01J 23/6482: {Vanadium} - B01J 37/0244: {Coatings comprising several layers} - B01J 37/0205: {in several steps} - B01J 37/0225: {of metal substrates} - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS ## Abstract The invention pertains to a layered ammonia oxidation catalyst. The layered catalyst causes ammonia to be selectively oxidized in the presence of an oxidant such as air, while minimizing the formation of nitrogen oxides (NOx). The layered catalyst comprises a refractory oxide support such as gamma alumina upon which a platinum component is deposited and a vanadia component is deposited on the platinum. The catalyst is preferably disposed on a substrate such as a metal foil whose surface contains a “herringbone” pattern. ## Claims ### Claim 1 A layered ammonia oxidation catalyst comprising a refractory metal oxide, a layer of platinum disposed upon the refractory metal oxide and a layer of vanadia disposed upon the platinum, wherein said vanadia is present in the amount of about 13 to about 104 g/ft3. ### Claim 2 (depends on 1) The catalyst of claim 1 that is disposed upon a substrate. ### Claim 3 (depends on 2) The catalyst of claim 2 wherein the substrate comprises a “FeCrAlloy” foil having a herringbone pattern impressed upon its surface. ### Claim 4 (depends on 2) The catalyst of claim 2 wherein the substrate comprises a refractory ceramic having a honeycomb structure. ### Claim 5 (depends on 1) The catalyst of claim 1 wherein the refractory metal oxide comprises gamma-alumina having a surface area of about 60 to about 300 m2/g. ### Claim 6 (depends on 1) The catalyst of claim 1 wherein the platinum is present in an amount of about 0.5 to about 4 wt. %, based on the weight of the refractory metal oxide. ### Claim 7 (depends on 6) The catalyst of claim 6 wherein the platinum is present in the amount of about 10 to about 100 g/ft3. ### Claim 8 A method for preparing an ammonia oxidation catalyst that comprises the steps of: (a) depositing a refractory metal oxide upon the surface of a substrate; (b) depositing a platinum component upon the surface of the substrate resulting from step (a); (c) drying and thereafter calcining the substrate resulting from step (b) at a temperature of about 300 to about 700° C.; (d) depositing a vanadium component upon the surface of the substrate resulting from step (c); and (e) drying and thereafter calcining the substrate resulting from step (d) at a temperature of about 300 to about 700° C. so as to form vanadia, wherein said vanadia is present in the amount of about 13 to about 104 g/ft3. ### Claim 9 (depends on 8) The method of claim 8 wherein the substrate comprises a “FeCrAlloy” foil having a herringbone pattern impressed upon its surface. ### Claim 10 (depends on 8) The method of claim 8 wherein the substrate comprises a refractory ceramic having a honeycomb structure. ### Claim 11 (depends on 8) The method of claim 8 wherein the refractory metal oxide comprises gamma-alumina surface area of about 60 to about 300 m2/g. ### Claim 12 (depends on 8) The method of claim 8 wherein the substrate resulting from step (a) is dried and thereafter calcined at a temperature of about 300 to about 700° C. before carrying out step (b). ### Claim 13 (depends on 8) The method of claim 8 wherein in step (a), the refractory metal oxide is deposited upon the surface of the substrate by dipping the substrate into an aqueous slurry of the refractory metal oxide. ### Claim 14 (depends on 8) The method of claim 8 wherein in step (b), the platinum component is deposited on the substrate resulting from step (a) by spraying the surface of such substrate with an aqueous solution of the platinum component. ### Claim 15 (depends on 14) The method of claim 14 wherein the platinum component is utilized in the form of an aqueous solution of an amine-solubilized platinum hydroxide. ### Claim 16 (depends on 8) The method of claim 8 wherein in step (d), the vanadium component is deposited onto the surface of the substrate resulting from step-(c) by dipping said substrate into an aqueous solution of the vanadium component. ### Claim 17 (depends on 16) The method of claim 16 wherein the vanadium component is utilized in the form of an aqueous solution of ammonium metavanadate. ### Claim 18 A process for selectively oxidizing ammonia present in an exhaust gas stream to nitrogen which comprises contacting the exhaust gas stream with a layered ammonia oxidation catalyst in the presence of an oxidant at a temperature of about 200 to about 375° C., said layered ammonia oxidation catalyst comprising a refractory metal oxide, a layer of platinum disposed upon the refractory metal oxide and a layer of vanadia disposed upon the platinum, wherein said vanadia is present in the amount of about 13 to about 104 g/ft3. ### Claim 19 (depends on 18) The process of claim 18 wherein the oxidant comprises a gaseous stream containing at least about 10 wt. % oxygen. ### Claim 20 (depends on 19) The process of claim 19 wherein the gaseous stream comprises air.