Rhodia Operations

Anan Kasei Co., Ltd.

Solvay Special Chem Japan, Ltd.

Naotaka Ohtake

Olivier Larcher

Emmanuel Rohart

Kazuhiko Yokota

Fabien Ocampo

Mitsuhiro Okazumi

Toshihiro Sasaki

Keiichiro Mitsuoka

Eisaku Suda

Thomas English

Francis Francis

Andrew D Polli

Manabu Yuasa

Rui Miguel Jorge Coelho Marques

Lauriane Dalencon

Jun Tokuda

The present invention relates to a mixed oxide composition based on zirconium and cerium, to the process for preparing it and to its use in the field of catalysis. The mixed oxide is characterized by a high specific surface area and a specific porosity after calcination at 1100° C.

Mixed oxide with high pore volume

The present invention relates to a mixed oxide with enhanced resistance and NOstorage capacity. The mixed oxide may be used as a component of a NOtrap material in an exhaust system of an internal combustion engine. The invention also relates to a method for treating an exhaust gas from an internal combustion engine using the mixed oxide.

Mixed oxide with enhanced resistance and NOx storage capacity

The present invention relates to cerium oxide particles that have excellent heat resistance and/or pore volume especially useful for catalysts, functional ceramics, solid electrolyte for fuel cells, polishing, ultraviolet absorbers and the like, and particularly suitable for use as a catalyst or cocatalyst material, for instance in catalysis for purifying vehicle exhaust gas. The present invention also relates to a method for preparing such cerium oxide particles, and a catalyst, such as for purifying exhaust gas, utilizing these cerium oxide particles.

Cerium oxide particles and method for production thereof

Provided are: a complex oxide that exhibits high redox ability even at low temperatures, has excellent heat resistance, and stably retains these characteristics even on repeated oxidation and reduction at high temperature; a method for producing the same; and an exhaust gas purification catalyst. The inventive complex oxide contains more than 0 but no more than 20 parts by mass of Si, calculated as SiO, per total 100 parts by mass of rare earth metal elements including Ce, calculated as oxides; and has a characteristic such that when it is subjected to temperature-programmed reduction (TPR) measurement in a 10% hydrogen-90% argon atmosphere at from 50&#xb0; C. to 900&#xb0; C. with the temperature increasing at a rate of 10&#xb0; C./min, followed by oxidation treatment at 500&#xb0; C. for 0.5 hours, and then temperature-programmed reduction measurement is performed again, its calculated reduction rate at and below 400&#xb0; C. is at least 1.5%.

Complex oxide, method for producing same, and exhaust gas purification catalyst

The present invention relates to cerium oxide particles that have excellent heat resistance especially useful for catalysts, functional ceramics, solid electrolyte for fuel cells, polishing, ultraviolet absorbers and the like, and particularly suitable for use as a catalyst or co-catalyst material, for instance in catalysis for purifying vehicle exhaust gas. The present invention also relates to a method for preparing such cerium oxide particles, and a catalyst, such as for purifying exhaust gas, utilizing these cerium oxide particles.

The present invention concerns a process for the production of metal doped cerium compositions comprising a cerium oxide and a metal oxide by precipitation. The invention also concerns metal doped cerium compositions providing high crystallites size and exhibiting high thermal stabilities, which may be used as a catalytic support or for polishing applications.

Metal doped cerium oxide compositions

Provided are: a complex oxide that exhibits high redox ability even at low temperatures, has excellent heat resistance, and stably retains these characteristics even on repeated oxidation and reduction at high temperature; a method for producing the same; and an exhaust gas purification catalyst. The inventive complex oxide contains Ce; rare earth metal element other than Ce, including Y; Al and/or Zr; and Si; such that the Ce, and said other elements other than Ce and Si, are present in a mass ratio of 85:15-99:1, calculated as oxides; and has a characteristic such that when it is subjected to temperature-programmed reduction (TPR) measurement in a 10% hydrogen-90% argon atmosphere at from 50&#xb0; C. to 900&#xb0; C. with the temperature increasing at a rate of 10&#xb0; C./min, followed by oxidation treatment at 500&#xb0; C. for 0.5 hours, and then temperature-programmed reduction measurement is performed again, its calculated reduction rate at and below 400&#xb0; C. is at least 2.0%.

Disclosed are a composite oxide which is capable of maintaining a large specific surface area even used in a high temperature environment, and which has excellent heat resistance and reducibility, as well as a method for producing the composite oxide and a catalyst for exhaust gas purification employing the composite oxide. The composite oxide contains cerium and at least one of rare earth metal elements other than cerium and including yttrium, at a mass ratio of 85:15 to 99:1 in terms oxides, and further containing silicon at more than 0 parts by mass and not more than 20 parts by mass in terms of SiOwith respect to 100 parts by mass of the total of the cerium and the at least one of rare earth metal elements other than cerium and including yttrium, wherein the composite oxide has a specific surface area of not less than 40 m/g as measured by the BET method after calcination at 900&#xb0; C. for 5 hours, and a reducibility of not lower than 30% as calculated from measurement of temperature-programmed reduction from 50&#xb0; C. to 900&#xb0; C. after calcination at 1000&#xb0; C. for 5 hours, and is particularly suitable for a co-catalyst for a catalyst for exhaust gas purification.

Complex oxide, method for producing same and exhaust gas purifying catalyst

Disclosed are a composite oxide which is capable of maintaining a large volume of pores even used in a high temperature environment, and which has excellent heat resistance and catalytic activity, as well as a method for producing the composite oxide and a catalyst for exhaust gas purification employing the composite oxide. The composite oxide contains cerium and at least one element selected from aluminum, silicon, or rare earth metals other than cerium and including yttrium, at a mass ratio of 85:15 to 99:1 in terms oxides, and has a property of exhibiting a not less than 0.30 cm/g, preferably not less than 0.40 cm/g volume of pores with a diameter of not larger than 200 nm, after calcination at 900&#xb0; C. for 5 hours, and is suitable for a co-catalyst in a catalyst for vehicle exhaust gas purification.

Complex oxide, method for producing same, and exhaust gas purifying catalyst

The present invention is directed to a high surface area, high pore volume porous alumina, comprising: aluminum oxide, optionally, silicon oxide and aluminosilicates, and optionally one or more dopants, said alumina having a specific surface area of from about 100 to about 500 square meters per gram and a total pore volume after calcination at 900&#xb0; C. for 2 hours of greater than or equal to 1.2 cubic centimeters per gram, wherein less than or equal to 15% of the total pore volume is contributed by pores having a diameter of less than 10 nm.

Alumina catalyst support

Disclosed are a silicon-containing cerium composite oxide which is capable of maintaining a large specific surface area even used in a high temperature environment, and which has excellent heat resistance and reducibility, as well as a method for producing the composite oxide and a catalyst for exhaust gas purification employing the composite oxide. The composite oxide contains 2 to 20 mass % silicon in terms of SiO, has properties of exhibiting a specific surface area of not less than 40 m/g as measured by the BET method after calcination at 1000&#xb0; C. for 5 hours, and a reducibility of not lower than 30% as calculated from measurement of temperature-programmed reduction from 50&#xb0; C. to 900&#xb0; C. after calcination at 1000&#xb0; C. for 5 hours, and is suitable for a co-catalyst for a catalyst for exhaust gas purification.

The mixed oxide of the invention mainly consists of cerium oxide and of at least one oxide of another rare earth. It has a specific surface area of at least 20 m/g after calcining at 1000&#xb0; C. for 5 hours. It is obtained by forming a liquid medium comprising a cerium compound; by heating this medium; by adding to the precipitate obtained a compound of the other rare earth, by heating the medium thus obtained and by bringing its pH to a basic value and by calcining the precipitate. The mixed oxide may be used as a catalyst support.

Growing community of inventors

Tokushima, Japan

Naotaka Ohtake