An object of the present invention is to provide a CeO.sub.2ZrO.sub.2-based complex oxide having a sufficiently reduced particle size and a method for producing the CeO.sub.2ZrO.sub.2-based complex oxide, and there are provided a complex oxide containing a zirconium element, a cerium element, and optionally another rare earth metal element, wherein D.sub.50 and D.sub.90 of the complex oxide measured by a laser diffraction scattering particle size distribution measurement method are 0.5 ?m or less and 1 ?m or less, respectively, and a method for producing the complex oxide.

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.

[Problem] Chabazite zeolites have a problem of low hydrothermal resistance. [Solution] By steam treating a chabazite zeolite having a silica-alumina ratio and a crystallinity that are within certain ranges, a chabazite zeolite having a high crystallinity and a high hydrothermal resistance can be obtained.

A method for synthesis of inorganic nanoparticles is disclosed. This synthesis method is single step, based on two heaters and functions using near ambient conditions. This flow method can be used to synthesize a range of inorganic particles. Synthesis of stoichiometric and non-stoichiometric hydroxyapatite with ranging thermal stabilities has been shown in this application. These materials find wide applications as biomaterials, in the form of additives to polymer based composites, for bone filling applications and also as coatings on metallic substrates.

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.

A composition including cerium and zirconium oxides, including at least 30 wt.-% cerium oxide is desired. Following calcination at a temperature of 900 DEG C. for 4 hours, the composition has two populations of pores, the diameters of the first population being centered around a value of between 5 nm and 15 nm for a composition including 30% to 65% cerium oxide or between 10 nm and 20 nm for more than 65% cerium oxide and the diameter of the second population being centered around a value of between 45 nm and 65 nm for 30% to 65% cerium oxide or between 60 nm and 100 nm for more than 65% cerium oxide.

The composition of the invention is based on oxides of cerium, of zirconium and of at least one rare earth metal other than cerium, with a cerium oxide content of greater than 50% by weight and it has, after calcination at 1000? C. for 4 hours, a specific surface area of at least 20 m.sup.2/g and an amount of mobile oxygen between 200? C. and 400? C. of at least 0.8 ml O.sub.2/g. It is prepared by a process in which, in a reactor, a mixture of compounds of cerium, of zirconium and of the other rare earth metal is reacted continuously with a basic compound with a residence time of the reaction medium in the mixing zone of the reactor of at most 100 milliseconds; the precipitate is heated then brought into contact with a surfactant before being calcined.

The invention relates to a composition containing zirconium, cerium and yttrium oxides with a cerium oxide proportion of between 3% and 15%, and yttrium oxide proportions corresponding to the following conditions: 6% at most if the cerium oxide proportion is between 12% excluded and 15% included; 10% at most if the cerium oxide proportion is between 7% excluded and 12% included; 30% at most if the cerium oxide proportion is between 3% and 7% included; the balance consisting of zirconium oxide. The composition may optionally include an oxide of a rare earth selected from lanthanum, neodymium and praseodymium. The composition can be used for processing the exhaust gases of a vehicle.

Composite particles that super-aggregates of coated aggregates having low structure carbon black cores and metal/metoxide mantles are described. Coatings containing filler-polymer compositions which have the composite particles as filler, such as curable coatings and cured coatings or films formed therefrom containing the filler-polymer compositions, with combinations of high resistivity, good optical density properties, good thermal stability, high dielectric constant, and good processability, along with their use in black matrices, black column spacers, light shielding elements in LCDs and other display devices, also are described. Inks containing the composite particle are described. Devices having these compositions, components and/or elements, and methods of preparing and making these various materials and products are described.

The invention relates to a mixed oxide composed of zirconium, cerium, lanthanum and at least one rare earth oxide other than cerium and lanthanum, having a specific porosity and a high specific surface area; to the method for preparing same and to the use thereof in catalysis.