Catalysts, catalytic materials having catalysts present on supports and catalytic methods are provided. The catalysts, catalytic material and methods are useful in a variety of catalytic reactions, for example, the oxidative coupling of methane.

The exhaust gas-purifying catalyst of the invention contains oxide particles having interdispersed therein A crystallites that are loaded with a noble metal and B crystallites that are not loaded with a noble metal. The A crystallites loaded with a noble metal are composed of an oxide containing at least one of zirconium (Zr) and cerium (Ce). The B crystallites not loaded with a noble metal are composed of a cerium (Ce)-containing oxide which has a higher Ce content (mol %) than the oxide making up the A crystallites. The oxide particles have a specific surface area after 5 hours of heat treatment at 1,150° C. in open air of 30 m.sup.2/g or more.

The exhaust gas-purifying catalyst of the invention contains oxide particles having interdispersed therein A crystallites that are loaded with a noble metal and B crystallites that are not loaded with a noble metal. The A crystallites loaded with a noble metal are composed of an oxide containing at least one of zirconium (Zr) and cerium (Ce). The B crystallites not loaded with a noble metal are composed of a cerium (Ce)-containing oxide which has a higher Ce content (mol %) than the oxide making up the A crystallites. The oxide particles have a specific surface area after 5 hours of heat treatment at 1,150° C. in open air of 30 m.sup.2/g or more.

The present invention relates to a metal oxide coated composite comprising a core consisting of a mixture of a La stabilised AI.sub.2O.sub.3 phase and an Ce/Zr/RE.sub.2O.sub.3 mixed oxide phase, the core having a specific crystallinity, specific pore volume and a specific pore size distribution, and a method for the production of the metal oxide coated composite.

The present invention relates to a metal oxide coated composite comprising a core consisting of a mixture of a La stabilised AI.sub.2O.sub.3 phase and an Ce/Zr/RE.sub.2O.sub.3 mixed oxide phase, the core having a specific crystallinity, specific pore volume and a specific pore size distribution, and a method for the production of the metal oxide coated composite.

A catalytic converter with excellent OSC performance and NO.sub.x purification performance. The converter includes a substrate with a cell structure through which exhaust gas flows, and a catalyst layer formed on a cell wall surface of the substrate. The catalyst layer includes a lower catalyst layer and an upper catalyst layer, the lower catalyst layer being formed on a surface of the substrate, and the upper catalyst layer being formed on a surface of the lower catalyst layer. The upper catalyst layer includes at least a zirconia support with rhodium carried thereon, and two types of ceria-zirconia-based composite oxides with different specific surface areas, each of the ceria-zirconia-based composite oxides having no rhodium carried thereon. The lower catalyst layer includes an alumina support with platinum carried thereon, and a ceria-zirconia-based composite oxide.

A catalytic converter with excellent OSC performance and NO.sub.x purification performance. The converter includes a substrate with a cell structure through which exhaust gas flows, and a catalyst layer formed on a cell wall surface of the substrate. The catalyst layer includes a lower catalyst layer and an upper catalyst layer, the lower catalyst layer being formed on a surface of the substrate, and the upper catalyst layer being formed on a surface of the lower catalyst layer. The upper catalyst layer includes at least a zirconia support with rhodium carried thereon, and two types of ceria-zirconia-based composite oxides with different specific surface areas, each of the ceria-zirconia-based composite oxides having no rhodium carried thereon. The lower catalyst layer includes an alumina support with platinum carried thereon, and a ceria-zirconia-based composite oxide.

The object of the present invention is to provide an exhaust gas purifying catalyst that can achieve high purification performance while suppressing H.sub.2S emissions. The object is solved by an exhaust gas purifying catalyst in which the top layer of a catalyst coating layer comprises a ceria-zirconia composite oxide having a pyrochlore-type ordered array structure, in which the ceria-zirconia composite oxide contains at least one additional element selected from the group consisting of praseodymium, lanthanum, and yttrium at 0.5 to 5.0 mol % in relation to the total cation amount, and the molar ratio of (cerium+additional element):(zirconium) is within the range from 43:57 to 48:52.

The object of the present invention is to provide an exhaust gas purifying catalyst that can achieve high purification performance while suppressing H.sub.2S emissions. The object is solved by an exhaust gas purifying catalyst in which the top layer of a catalyst coating layer comprises a ceria-zirconia composite oxide having a pyrochlore-type ordered array structure, in which the ceria-zirconia composite oxide contains at least one additional element selected from the group consisting of praseodymium, lanthanum, and yttrium at 0.5 to 5.0 mol % in relation to the total cation amount, and the molar ratio of (cerium+additional element):(zirconium) is within the range from 43:57 to 48:52.

A process includes reacting a feed stream containing ethanol and optionally acetaldehyde in a dehydration reactor in the presence of a dehydration catalyst system having a Group 4 or Group 5 metal oxide and a support. The process includes obtaining a product stream containing butadiene from the dehydration reactor. Another process includes reacting a feed stream containing ethanol and optionally acetaldehyde in a dehydration reactor in the presence of a dehydration catalyst system containing a tungsten oxide supported on a zeolite or a tantalum oxide supported on a zeolite. The process includes obtaining a product stream containing butadiene from the dehydration reactor.