# US 2013/0239556 A1 · Production method for exhaust gas-purifying catalyst and motor vehicle > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2013/0239556 A1 - Document ID: US20130239556A1 - Status: Published application - Kind: A1 - Application number: 13/883,634 - Filed: 2011-11-25 - Published: 2013-09-19 - Earliest claimed: 2010-12-06 - Assignees: Yamaha Hatsudoki Kabushiki Kaisha - Inventors: Yutaka Itou; Naohiro Morozumi - Web page: https://patentgrep.com/patent/US20130239556A1 ## CPC - B01J 23/63: with rare earths or actinides - B01J 21/066: {Zirconium or hafnium; Oxides or hydroxides thereof} - B01J 23/464: {Rhodium} - B01J 35/394: {Metal dispersion value, e.g. percentage or fraction} - B01J 37/0213: {Preparation of the impregnating solution} - B01J 37/0248: {Coatings comprising impregnated particles} - B01J 37/035: {Precipitation on carriers} - F01N 3/28: Construction of catalytic reactors - B01D 53/94: by catalytic processes - B01D 2255/1025: Rhodium - B01D 2255/2063: Lanthanum - B01D 2255/2065: Cerium - B01D 2255/2068: Neodymium - B01D 2255/20715: Zirconium - F01N 3/2828: {Ceramic multi-channel monoliths, e.g. honeycombs} - F01N 2590/04: for motorcycles - Y02A 50/20: Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - F01N: GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL-COMBUSTION ENGINES (arrangements in connection with gas exhaust of propulsion units in vehicles B60K13/00; combustion-air intake silencers specially adapted for, or arranged on, internal-combustion engines F02M35/00; protecting against, or damping, noise in general G10K11/16) - 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) - Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE ## Abstract A method for producing an exhaust gas purifying catalyst according to the present invention includes step (a) of preparing a metal oxide support containing zirconium; step (b) of preparing a solution containing rhodium; and step (c) of adding the metal oxide support prepared in the step (a), and ammonium carbonate, ammonium hydrogencarbonate or ammonia water, to the solution prepared in the step (b) to obtain the solution having a pH adjusted to a range of 3.0 or higher and 7.5 or lower. The present invention provides a method capable of producing an exhaust gas purifying catalyst including a metal oxide support containing zirconium and rhodium of a minute particle size which is supported on the metal oxide support at a high degree of dispersion. ## Claims ### Claim 1 A method for producing an exhaust gas purifying catalyst, comprising: step (a) of preparing a metal oxide support containing zirconium; step (b) of preparing a solution containing rhodium; and step (c) of adding the metal oxide support, and ammonium carbonate or ammonium hydrogencarbonate or ammonia water, to the solution to obtain the solution having a pH adjusted to a range of 3.0 or higher and 7.5 or lower. ### Claim 2 (depends on 1) The method for producing an exhaust gas purifying catalyst of claim 1, wherein the step (c) includes: step (c-1A) of mixing the metal oxide support in the solution; and step (c-2A) of adding ammonium carbonate, ammonium hydrogencarbonate or ammonia water to the solution after the step (c-1A) to adjust the pH of the solution to a range of 3.0 or higher and 7.5 or lower. ### Claim 3 (depends on 1) The method for producing an exhaust gas purifying catalyst of claim 1, wherein the step (c) includes: step (c-1B) of adding ammonium carbonate, ammonium hydrogencarbonate or ammonia water to the solution to adjust the pH of the solution to a prescribed range; and step (c-2B) of mixing the metal oxide support in the solution after the step (c-1B); wherein the prescribed range in the step (c-1B) is set such that the pH of the solution becomes a value in a range of 3.0 or higher and 7.5 or lower after the step (c-2B) is performed. ### Claim 4 (depends on 1) The method for producing an exhaust gas purifying catalyst of claim 1, wherein the pH of the solution obtained in the step (c) is in a range of 4.0 or higher and 6.5 or lower. ### Claim 5 (depends on 1) The method for producing an exhaust gas purifying catalyst of claim 1, wherein the metal oxide support prepared in the step (a) contains zirconium in a range of 50 mol % or higher and 95 mol % or lower as being converted into an oxide. ### Claim 6 (depends on 5) The method for producing an exhaust gas purifying catalyst of claim 5, wherein the metal oxide support prepared in the step (a) contains zirconium in a range of 70 mol % or higher and 90 mol % or lower as being converted into an oxide. ### Claim 7 (depends on 1) The method for producing an exhaust gas purifying catalyst of claim 1, wherein the metal oxide support prepared in the step (a) contains at least one metal material selected from the group consisting of cerium, lanthanum and neodymium. ### Claim 8 (depends on 1) The method for producing an exhaust gas purifying catalyst of claim 1, wherein the solution prepared in the step (b) has an absorbance of 0.8 or less for a ray having a wavelength of 300 nm. ### Claim 9 (depends on 1) The method for producing an exhaust gas purifying catalyst of claim 1, wherein the solution prepared in the step (b) has a chlorine content of 1000 ppm or less. ### Claim 10 (depends on 1) The method for producing an exhaust gas purifying catalyst of claim 1, further comprising step (d) of drying and burning the solution after the step (c) to obtain catalyst powder containing the metal oxide support and rhodium supported thereon. ### Claim 11 (depends on 10) The method for producing an exhaust gas purifying catalyst of claim 10, further comprising step (e) of forming a catalyst layer by use of the catalyst powder on a surface of a honeycomb-like substrate. ### Claim 12 (depends on 1) A motor vehicle, comprising: an internal combustion engine; an exhaust pipe for guiding exhaust gas from the internal combustion engine to outside; and the exhaust gas purifying catalyst produced by the method for producing an exhaust gas purifying catalyst of claim 1 and provided in the exhaust pipe.