The purpose of the present invention is to provide a zirconia-based composite oxide for making it possible to form a catalyst layer which, despite having a reduced thickness, has a sufficient quantity of catalyst to function in exhaust gas treatment on a wall of a honeycomb structure. The purpose of the present invention is also to provide a method for manufacturing said zirconia-based composite oxide. The present invention relates to a zirconia-based composite oxide characterized in that the tap bulk density thereof is 0.75 g/mL or greater, and the specific surface area thereof after heat treatment for three hours at 1000° C. is 45 m.sup.2/g or greater.

The present invention relates to a metal oxide coated composite comprising a core consisting of a mixture of a La stabilized Al.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 stabilized Al.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.

High surface area, high entropy oxides comprising multiple metal cations in a single-phase fluorite lattice material enables intrinsic catalytic activity without platinum group metals, tunable oxygen storage capacity, and thermal stability. These properties can be obtained through a facile sol-gel synthesis to provide a low-temperature route for production of phase-pure multi-cationic oxides. The resulting materials achieved significantly higher surface area and catalytic performance, taking advantage of all the properties endowed by the various cations in the composition.

High surface area, high entropy oxides comprising multiple metal cations in a single-phase fluorite lattice material enables intrinsic catalytic activity without platinum group metals, tunable oxygen storage capacity, and thermal stability. These properties can be obtained through a facile sol-gel synthesis to provide a low-temperature route for production of phase-pure multi-cationic oxides. The resulting materials achieved significantly higher surface area and catalytic performance, taking advantage of all the properties endowed by the various cations in the composition.

A method for preparing a compound of formula RSH where R represents an alkyl group, by gas-phase catalytic reaction of hydrogen sulfide with a compound of formula ROH, in the presence of a solid catalyst, according to which method the reaction is performed in the presence of a catalyst which includes one or several pure or mixed rare-earth oxide(s), one or several pure or mixed rare-earth sulfide(s), or one or several pure or mixed rare-earth oxysulfide(s). When the rare earth is lanthanum, the catalyst is a mixed oxide of lanthanum and of at least one metal selected from rare earths or not and when the rare earth is cerium, the catalyst is supported on an alumina.

A method for preparing a compound of formula RSH where R represents an alkyl group, by gas-phase catalytic reaction of hydrogen sulfide with a compound of formula ROH, in the presence of a solid catalyst, according to which method the reaction is performed in the presence of a catalyst which includes one or several pure or mixed rare-earth oxide(s), one or several pure or mixed rare-earth sulfide(s), or one or several pure or mixed rare-earth oxysulfide(s). When the rare earth is lanthanum, the catalyst is a mixed oxide of lanthanum and of at least one metal selected from rare earths or not and when the rare earth is cerium, the catalyst is supported on an alumina.

A nitrous oxide (N.sub.2O) removal catalyst composite is provided, comprising a N.sub.2O removal catalytic material on a substrate, the catalytic material comprising a rhodium (Rh) component supported on a ceria-based support, wherein the catalyst composite has a H.sub.2-consumption peak of about 100° C. or less as measured by hydrogen temperature-programmed reduction (H.sub.2-TPR). Methods of making and using the same are also provided.

A nitrous oxide (N.sub.2O) removal catalyst composite is provided, comprising a N.sub.2O removal catalytic material on a substrate, the catalytic material comprising a rhodium (Rh) component supported on a ceria-based support, wherein the catalyst composite has a H.sub.2-consumption peak of about 100° C. or less as measured by hydrogen temperature-programmed reduction (H.sub.2-TPR). Methods of making and using the same are also provided.

This invention relates to azirconium hydroxideor zirconium oxide comprising, on an oxide basis, up to 30 wt % of a dopant comprising one or more of silicon, sulphate, phosphate, tungsten, niobium, aluminium, molybdenum, titanium or tin, and having acid sites, wherein the majority of the acid sites are Lewis acid sites. In addition, the invention relates to a catalyst, catalyst support or precursor, binder, functional binder, coating or sorbent comprising the zirconium hydroxide or zirconium oxide. The invention also relates to a process for preparing zirconium hydroxide, the process comprising the steps of:(a) dissolving a zirconium salt in an aqueous acid, (b) addingone or more complexing agents to the resulting solution or sol, the one or more complexing agents being an organic compound comprising at least one of the following functional groups: an amine, an organosulphate, a sulphonate, a hydroxyl, an ether or a carboxylic acid group, (c) heating the solution or sol formed in step (b), (d) adding a sulphating agent, and (e) adding a base to form a zirconium hydroxide, and (f) optionally adding a dopant.