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.

This invention relates to azirconium solution or sol comprising: (a) zirconium, (b) nitrate, acetate and/or chloride ions, and (c) 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, wherein the molar ratio of components (a):(b) is 1:0.7 to 1:4.0, the molar ratio of components (a):(c) is 1:0.0005 to 1:0.1, and the pH of the zirconium solution or sol is less than 5. The invention also relates to a process for preparing a zirconium solution or sol, the process comprising the steps of: (a) dissolving a zirconium salt in nitric, acetic and/or hydrochloric acid, and (b) adding one or more complexing agents to the resulting solution, 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, and (c) heating the solution or sol to a temperature of at least 75? C. In addition, the invention relates to products formed from the zirconium solution or sol or obtainable by the process.

This invention relates to a cerium-zirconium based mixed oxide having: (a) a Ce:Zr molar ratio of 1 or less, and (b) a cerium oxide content of 10-50% by weight, wherein the composition has (i) a surface area of at least 18 m.sup.2/g, and a total pore volume as measured by N.sub.2 physisorption of at least 0.11 cm.sup.3/g, after ageing at 1100? C. in an air atmosphere for 6 hours, and (ii) a surface area of at least 42 m.sup.2/g, and a total pore volume as measured by N.sub.2 physisorption of at least 0.31 cm.sup.3/g, after ageing at 1000? C. in an air atmosphere for 4 hours. The invention also relates to a catalytic system comprising the cerium-zirconium based mixed oxide, as well as to a process 10 for treating an exhaust gas from a vehicle engine comprising contacting the exhaust gas with the cerium-zirconium based mixed oxide. In addition, the invention relates to a process for preparing a cerium-zirconium based mixed hydroxide or mixed oxide as claimed in any preceding claim, the process comprising the steps of: (a) dissolving a zirconium salt in an aqueous acid, (b) adding one or more complexing agents to the resulting solution, 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 cerium salt, and adding a sulphating agent either before or after the addition of the cerium salt, and (e) adding a base to form a cerium-zirconium based mixed hydroxide.

A process for producing alumina, the process having a seeding phase and a precipitation phase. During the seeding phase a seed mixture is produced by adding an aluminium salt to an aqueous solution and then adding an alkaline metal aluminate to the mixture while maintaining the seed mixture at generally neutral pH. The precipitation phase produces precipitated alumina by simultaneously adding aluminium salt and alkaline metal aluminate to the seed mixture while maintaining a pH from 6.9 to 7.8. The recovered precipitated alumina has at least one, preferably all the following characteristics: i) a crystallite size of 33-42 Ang.: in the (120) diagonal plane (using XRD).; ii) a crystallite d-spacing (020) of between 6.30-6.59 Ang.; iii) a high porosity with an average pore diameter of 115-166 Ang.; iv) a relatively low bulk density of 250-350 kg/m.sup.3; v) a surface area after calcination for 24 hours at 1100 C. of 60-80 m.sup.2/g; and vi) a pore volume after calcination for one hour at 1000 C. 0.8-1.1 m.sup.3/g.

This invention provides a zirconia-based porous body having a pore diameter suitable for supporting catalytic active species, such as precious metals, small variability in pore diameter, and a sufficient specific surface area even after 12-hour heating at 1000 C. Specifically, the invention provides a zirconia-based porous body in particle form having (1) a pore diameter peak at 20 to 100 nm in the pore distribution by BJH method, a P/W ratio of 0.05 or more wherein W represents half width of the peak and P represents height of the peak in the measured pore distribution curve, and a total pore volume of 0.5 cm.sup.3/g or more; and (2) a pore diameter peak at 20 to 100 nm, the P/W ratio of 0.03 or more, a specific surface area of at least 40 m.sup.2/g, and a total pore volume of 0.3 cm.sup.3/g or more, after heat treatment at 1000 C. for 12 hours.

A process for preparing a mesoporous metal oxide, i.e., transition metal oxide. Lanthanide metal oxide, a post-transition metal oxide and metalloid oxide. The process comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to form the mesoporous metal oxide. A mesoporous metal oxide prepared by the above process. A method of controlling nano-sized wall crystallinity and mesoporosity in mesoporous metal oxides. The method comprises providing an acidic mixture comprising a metal precursor, an interface modifier, a hydrotropic ion precursor, and a surfactant; and heating the acidic mixture at a temperature and for a period of time sufficient to control nano-sized wall crystallinity and mesoporosity in the mesoporous metal oxides. Mesoporous metal oxides and a method of tuning structural properties of mesoporous metal oxides.

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 SiO.sub.2 with 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.sup.2/g as measured by the BET method after calcination at 900? C. for 5 hours, and a reducibility of not lower than 30% as calculated from measurement of temperature-programmed reduction from 50? C. to 900? C. after calcination at 1000? C. for 5 hours, and is particularly suitable for a co-catalyst for a catalyst for exhaust gas purification.

The present invention relates to novel totally-mesoporous zirconium oxide nanoparticles as well as a sol-gel synthesis process thereof which include an innovative nanoparticles purification step. Said nanoparticles are characterized by a totally-mesoporous structure i.e. a distribution of pores within the so-called the mesoporous range uniformly distributed throughout the entire nanoparticle volume. Furthermore, said nanoparticles are non-cytotoxic and present a high surface area, which make particularly suitable in both biomedical and industrial applications (e.g. drug delivery, heavy metals ion sequestration). The manufacturing method is simple and advantageously allows for high control over the shape and diameter of the nanoparticles as well as over the nanoparticles pores.

The present invention is a carbon nanotube aggregate having a three-dimensional shape. The carbon nanotube aggregate having a three-dimensional shape includes a first surface, a second surface and a side surface, wherein a carbon nanotube of the first surface has a Herman orientation coefficient greater than 0.1 and smaller than 0.2, a carbon nanotube of the second surface has a Herman orientation coefficient greater than 0.1 and smaller than 0.2, and a carbon nanotube of the side surface has degree of orientation in which a Herman orientation coefficient is 0.2 or more and 0.99 or less, and the first surface and second surface are mutually arranged in parallel and the side surface is perpendicular with respect to the first surface and second surface.

A process for forming an active cathode material. The process comprises forming a precursor comprising a lithium salt and a multi-carboxylic acid salt of at least one of nickel, manganese or cobalt; heating the precursor in a metal lined vessel to a temperature of no more than 600 C. to form an intermediate material; and heating the intermediate material to a temperature of over 600 C. to form said active cathode material.