A starting material powder, which contains a rare earth oxide that is composed of terbium oxide and at least one other rare earth oxide selected from among yttrium oxide, scandium oxide and oxides of lanthanide rare earth elements (excluding terbium) and a sintering assistant that is formed of an oxide of at least one element selected from among group 2 elements and group 4 elements, is produced by having (a) terbium ions, (b) ions of at least one other rare earth element selected from among yttrium ions, scandium ions and lanthanide rare earth ions (excluding terbium ions) and (c) ions of at least one element selected from among group 2 elements and group 4 elements coprecipitate in an aqueous solution containing the components (a)-(c), then filtering and separating the coprecipitate, and subjecting the separated coprecipitate to thermal dehydration.

A method for producing a metal oxide nanocrystals according to the embodiment of the present invention comprises continuously flowing a nanocrystal precursor solution comprising a nanocrystal precursor into a continuous flow path and heating the nanocrystal precursor solution in the continuous flow path to create nanocrystals, comprising: providing a nanocrystal precursor solution supply unit that is connected to the continuous flow path and comprises a first vessel and a second vessel; delivering a nanocrystal precursor solution in the second vessel to the continuous low path; and creating a nanocrystal precursor solution in the first vessel as a different batch from the nanocrystal precursor solution in the second vessel.

Nanowires useful as heterogeneous catalysts are provided. The nanowire catalysts are prepared by polymer templated methods and are useful in a variety of catalytic reactions, for example, the oxidative coupling of methane to ethane and/or ethylene. Related methods for use and manufacture of the same are also disclosed.

Nanowires useful as heterogeneous catalysts are provided. The nanowires catalysts are useful in a variety of catalytic reactions, for example, the oxidative coupling of methane to ethylene. Related methods for use and manufacture of the same are also disclosed.

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

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 lower layer of the 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.

Rare earth compound particles are prepared by a step of heating an aqueous solution containing rare earth metal ions and urea to form a rare earth compound by a reaction of a hydrolysis product of urea, and the rare earth metal ions. In the heating step, heating the aqueous solution into which an acetylene glycol-ethylene oxide adduct is added.

The invention relates to a method for preparing a composite metal oxide hollow fibre. A certain stoichiometry of composite metal oxide raw material and a polymer binding agent are added to an organic solvent, and mixed mechanically to obtain an evenly dispersed spinning solution having a suitable viscosity. After defoaming treatment, the spinning solution is extruded through a spinneret and, after undergoing a certain dry spinning process, enters an external coagulation bath; during this period, a phase inversion process occurs and composite metal oxide hollow fibre blanks are formed. The blanks are immersed in the external coagulation bath and the organic solvent is displaced; after natural drying, the blanks undergo a heat treatment process; during this period, polymer burn off, in situ reaction, and in situ sintering processes occur to obtain the composite metal oxide hollow fibre.

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 slurry of a dispersion medium and rare earth oxide particles. The particles having a volume basis median particle size D50 of up to 50 nm. The rare earth oxide particles having a dispersity index S of up to 1, the dispersity index S being determined according to the formula (1):
(D90D10)/D50(1) wherein D10, D50 and D90 are cumulative 10%, 50% and 90% diameters in volume basis particle size distribution, respectively.