Abstract: Provided are an exhaust gas purification catalyst comprising a nanocomposite material comprising CeO2 and NiO which are uniformly mixed; and a production method thereof. The uniform mixing satisfies at least one of following conditions: (a) when the nanocomposite material is analyzed using STEM-EDX, the number of Ni atoms is from 3 to 20 atomic % relative to the total number of Ni and Ce atoms at a majority of randomly selected 5 or more measurement points in which both Ce and Ni elements are detected; and (b) in the Fourier transform of EXAFS spectrum at Ni—K absorption edge regarding the nanocomposite material, the ratio of the peak intensity of Ni—O near an interatomic distance of 1.8 ? to the peak intensity of Ni—Ni near an interatomic distance of 2.6 ? is 1:at least 0.50 to less than 2.18.

Abstract: An exhaust gas purification catalyst of the present invention includes a catalyst support and a plurality of bimetallic particles supported thereon wherein the bimetallic particles consist of gold and cobalt and have an average particle size of greater than 0 nm but 100 nm or less. A method of the present invention includes heating a mixed solution containing a gold salt, a cobalt salt, a solvent and an inorganic reducing agent to a temperature sufficient to reduce gold and cobalt, thereby producing bimetallic particles consisting of gold and cobalt, and supporting the produced bimetallic particles on the catalyst support.

Abstract: A method of synthesizing metal composite oxide, the method including: a step of separately introducing into a high-speed stirring apparatus a ceria composite oxide microparticle colloid having a mean particle diameter of 10 nm or less after adding a dispersant and an alumina microparticle colloid having a mean particle diameter of 10 nm or less after adding a dispersant; a step of synthesizing alumina-ceria composite oxide microparticles by allowing the ceria composite oxide microparticles and the alumina microparticles that have been introduced into the high-speed stirring apparatus to react in a microscopic space; and a step of applying a shearing force of 17000 sec?1 or more to the alumina-ceria composite oxide microparticles.

Abstract: Provided are metal particles comprising an at least partial solid solution of rhodium and gold. Also provided is a method for producing metal particles comprising adding a boron-based reducing agent to a mixed solution containing a rhodium salt and a gold salt to produce the metal particles comprising an at least partial solid solution of rhodium and gold. Furthermore, provided are an exhaust gas purifying catalyst comprising the metal particles supported on a catalyst support and a method for producing the same.

Abstract: The purpose of the present invention is to provide an exhaust gas purification catalyst which can decrease a NOx reduction temperature and comprises rhodium and gold. An exhaust gas purification catalyst which carries two-element microparticles each comprising rhodium and gold, said catalyst being characterized in that the rhodium and the gold are phase-separated from each other and the content ratio of the rhodium to the gold (i.e., rhodium:gold) is (30-99.9 at. %):(70-0.1 at. %) in the two-element microparticles.

Abstract: An exhaust gas purification catalyst of the present invention includes a catalyst support and a plurality of bimetallic particles supported thereon wherein the bimetallic particles consist of gold and cobalt and have an average particle size of greater than 0 nm but 100 nm or less. A method of the present invention includes heating a mixed solution containing a gold salt, a cobalt salt, a solvent and an inorganic reducing agent to a temperature sufficient to reduce gold and cobalt, thereby producing bimetallic particles consisting of gold and cobalt, and supporting the produced bimetallic particles on the catalyst support.

Abstract: The purpose of the present invention is to provide an exhaust gas purification catalyst which can decrease a NOx reduction temperature and comprises rhodium and gold. An exhaust gas purification catalyst which carries two-element microparticles each comprising rhodium and gold, said catalyst being characterized in that the rhodium and the gold are phase-separated from each other and the content ratio of the rhodium to the gold (i.e., rhodium:gold) is (30-99.9 at. %):(70-0.1 at. %) in the two-element microparticles.

Abstract: Provided are metal particles comprising an at least partial solid solution of rhodium and gold. Also provided is a method for producing metal particles comprising adding a boron-based reducing agent to a mixed solution containing a rhodium salt and a gold salt to produce the metal particles comprising an at least partial solid solution of rhodium and gold. Furthermore, provided are an exhaust gas purifying catalyst comprising the metal particles supported on a catalyst support and a method for producing the same.

Abstract: A method of synthesizing metal composite oxide, the method including: a step of separately introducing into a high-speed stirring apparatus a ceria composite oxide microparticle colloid having a mean particle diameter of 10 nm or less after adding a dispersant and an alumina microparticle colloid having a mean particle diameter of 10 nm or less after adding a dispersant; a step of synthesizing alumina-ceria composite oxide microparticles by allowing the ceria composite oxide microparticles and the alumina microparticles that have been introduced into the high-speed stirring apparatus to react in a microscopic space; and a step of applying a shearing force of 17000 sec?1 or more to the alumina-ceria composite oxide microparticles.