N.e. Chemcat Corporation

Daiichi Kigenso Kagaku Kogyo Co., Ltd.

Yoshiro Hirasawa

Takashi Yamada

Akira Kohara

Katsuaki Kato

Katsuaki Katoh

Yasunori Toyoda

An apparatus for purifying exhaust gas exhausted from an internal combustion engine, using two or more honeycomb structure-type catalysts (X) and (Y). The catalyst (X) contains the support material of the zirconium oxide as a main component which loads a Rh component on the support material of zirconium oxide and substantially does not contain a cerium component, and a cerium-containing oxide which substantially does not load the Rh component, and the catalyst (X) does not substantially contain Pt component and Pd component. The catalyst (Y) contains the support material of the cerium-zirconium composite oxide as a main component which loads a Rh component on the support material of cerium-zirconium composite oxide and which contains cerium of 1 to 20% by weight, in an oxide equivalent, and zirconium of 99 to 80% by weight, in an oxide equivalent, and the catalyst (Y) does not substantially contain Pt component and Pd component.

Apparatus of catalyst for purifying exhaust gas and method for purifying exhaust gas

An exhaust gas purification catalyst, which is suitable as a three way catalyst for efficiently purifying carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) in exhaust gas discharged from a gasoline automobile and exhaust gas purification apparatus using the same and an exhaust gas purification method. &#x3c;The upper layer&#x3e; A catalyst composition having an activated metal (A), a heat resistant inorganic oxide (B) and a cerium-zirconium-type composite oxide (C) containing a pyrochlore phase in a crystal structure, wherein the activated metal (A) is rhodium. &#x3c;The lower layer&#x3e; A catalyst composition having an activated metal (A), a heat resistant inorganic oxide (B) and a cerium-containing oxide (C') having a cubic crystal and/or tetragonal crystal structure as a major crystal structure, wherein the activated metal (A) is palladium, or palladium and platinum.

Exhaust gas purification catalyst, exhaust gas purification apparatus using the same and exhaust gas purification method

A catalyst system to be used in an automobile exhaust gas purification apparatus which exerts excellent purification capability to a nitrogen oxide, even when hydrocarbon concentration varies, by subjecting exhaust gas discharged from an automotive internal engine to contacting with a catalyst, an exhaust gas purification apparatus using the same, and an exhaust gas purification method. A catalyst system etc. to be used in an automobile exhaust gas purification apparatus, composed by using two or more exhaust gas purification catalysts, containing a first catalyst supported on an inorganic structural carrier and a second catalyst other than this, characterized by having the first catalyst supported on apart of the inorganic structural carrier positioned at the upstream side, when arranged in an exhaust gas passage; on the other hand having the second catalyst supported on a part of the inorganic structural carrier, positioned at the downstream side, when arranged in an exhaust gas passage; and containing a cerium-zirconium-type composite oxide (A) having a pyrochlore phase in the crystal structure.

Catalyst system to be used in automobile exhaust gas purification apparatus, exhaust gas purification apparatus using the same and exhaust gas purification method

The present invention provides a catalyst system for vehicle exhaust gas purification devices which exhibit excellent capacity of removing nitrogen oxide emissions from internal combustion engine exhaust gases when they are brought into contact with the catalyst even when hydrocarbon concentration in exhaust gases varies, exhaust gas purification device using the same and method for purification of exhaust gases. The catalyst system for vehicle exhaust gas purification devices comprises two or more exhaust gas purification catalysts including two different exhaust gas purification catalysts (first and second catalysts), each supported on an inorganic structural carrier and disposed in an exhaust gas passage, wherein the first catalyst is located on the upstream side in the exhaust gas passage, and the second downstream-side catalyst contains a cerium/zirconium-base compound oxide (A), prepared by melting a starting mixture at its melting point or higher, the molten mixture being then cooled to produce an ingot and crushed.

Catalyst system for vehicle exhaust gas purification devices, exhaust gas purification device using the same, and method for purification of exhaust gases

Growing community of inventors

Numazu, Japan

Yoshiro Hirasawa