Abstract: Catalyst compositions for the treatment of vehicular exhaust gases are based on zirconium and cerium oxides, have a cerium oxide content of at most 50% by weight, a level of reducibility of at least 95% after calcination in air at 600°, and a specific surface area after calcination for 4 hours at 1100° of at least 15 m2/g; such compositions are prepared by forming an aqueous mixture containing zirconium and cerium compounds, by heating this mixture to at least 100° and, after the heating, adjusting it to a basic pH, by adding a surfactant additive to the precipitate obtained from this mixture and by calcinating the precipitate in an inert gas or under vacuum at a temperature of at least 900° and then in an oxidizing atmosphere at a temperature of at least 600°.

Abstract: Catalyst compositions for the treatment of vehicular exhaust gases are based on zirconium and cerium oxides, have a cerium oxide content of at most 50% by weight, a level of reducibility of at least 95% after calcination in air at 600°, and a specific surface area after calcination for 4 hours at 1100° of at least 15 m2/g; such compositions are prepared by forming an aqueous mixture containing zirconium and cerium compounds, by heating this mixture to at least 100° and, after the heating, adjusting it to a basic pH, by adding a surfactant additive to the precipitate obtained from this mixture and by calcinating the precipitate in an inert gas or under vacuum at a temperature of at least 900° and then in an oxidizing atmosphere at a temperature of at least 600°.

Abstract: The present invention relates to ceric oxide that has excellent heat resistance and oxygen absorbing and desorbing capability useful as a co-catalyst material suitable for a catalyst for purifying exhaust gas, that is capable of maintaining a large specific surface area even in use in a high temperature environment, and that is suitable for use in a high temperature environment, yet capable of exhibiting high oxygen absorbing and desorbing capability also in a lower temperature range, a method for preparing such ceric oxide, and a catalyst for purifying exhaust gas utilizing such ceric oxide. The ceric oxide is an oxide composed essentially of ceric oxide, and has a specific surface area of not smaller than 30.0 m2/g after calcination at 900° C. for 5 hours.

Abstract: The present invention relates to ceric oxide that has excellent heat resistance and oxygen absorbing and desorbing capability useful as a co-catalyst material suitable for a catalyst for purifying exhaust gas, that is capable of maintaining a large specific surface area even in use in a high temperature environment, and that is suitable for use in a high temperature environment, yet capable of exhibiting high oxygen absorbing and desorbing capability also in a lower temperature range, a method for preparing such ceric oxide, and a catalyst for purifying exhaust gas utilizing such ceric oxide. The ceric oxide is an oxide composed essentially of ceric oxide, and has a specific surface area of not smaller than 30.0 m2/g after calcination at 900° C. for 5 hours.

Abstract: The invention provides a cerium based composite oxide and its production method, which hardly forms aggregates, is composed of particular acicular particles providing sinterable ceramic materials, has a sharp particle size distribution, and inhibited from aggregating. The composite oxide contains 0.1–50 mol % of metal such as Y, Sc, or rare earth elements excluding Ce and Pm, in terms of oxides, and 50 to 99.9 mol % of cerium in terms of oxides, wherein the composite oxide takes the acicular primary particle form having an average aspect ratio of 1.05–10.0, or secondary particle form, aggregates of the primary particles. The composite oxide containing the primary and second particles have a BET specific surface area of 5 to 40 m2/g, an average particle size of 0.1 to 0.5 ?m, and a particle size distribution index represented by formula (1) of not higher than 1.6: Particle Size Distribution Index=(D84?D16)/(2×D50).

Abstract: The invention provides a cerium based composite oxide and its production method, which hardly forms aggregates, is composed of particular acicular particles providing sinterable ceramic materials, has a sharp particle size distribution, and inhibited from aggregating. The composite oxide contains 0.1-50 mol % of metal such as Y, Sc, or rare earth elements excluding Ce and Pm, in terms of oxides, and 50 to 99.9 mol % of cerium in terms of oxides, wherein the composite oxide takes the acicular primary particle form having an average aspect ratio of 1.05-10.0, or secondary particle form, aggregates of the primary particles. The composite oxide containing the primary and second particles have a BET specific surface area of 5 to 40 m2/g, an average particle size of 0.1 to 0.5 ?m, and a particle size distribution index represented by formula (1) of not higher than 1.6: Particle Size Distribution Index=(D84?D16)/(2×D50) ??(1).

Abstract: The present invention relates to ceric oxide that has excellent heat resistance and oxygen absorbing and desorbing capability useful as a co-catalyst material suitable for a catalyst for purifying exhaust gas, that is capable of maintaining a large specific surface area even in use in a high temperature environment, and that is suitable for use in a high temperature environment, yet capable of exhibiting high oxygen absorbing and desorbing capability also in a lower temperature range, a method for preparing such ceric oxide, and a catalyst for purifying exhaust gas utilizing such ceric oxide. The ceric oxide is an oxide composed essentially of ceric oxide, and has a specific surface area of not smaller than 30.0 m2/g after calcination at 900° C. for 5 hours.

Abstract: The invention concerns titanium dioxide particles coated at least partially: with a first layer of at least a cerium and/or iron compound, and a second layer of at least a metal oxide, hydroxide or oxohydroxide, the said particles having a BET specific surface area of at least 70 m2/g and a density of 2.5. The invention also concerns a method for preparing these particles and their use as anti-UV agent.

Abstract: Very finely divided ammonium rare earth double oxalates, readily converted into corresponding rare earth oxides by calcination, such oxides being well adopted, e.g., for the production of luminescent compounds therefrom, are prepared by (a) admixing a second solution of a rare earth compound, e.g., a salt, with a first solution containing oxalate and ammonium ions, (b) then separating the precipitate thus obtained from such mixed solution of reaction, and (c) optionally, drying the separated precipitate.

Abstract: Adsorbent material well adapted for the purification of gases (notably by the PSA and TSA methods) by adsorbing impurities therefrom that are more polar or polarizable than the gases to be purified, e.g., nitrogen, the oxides of carbon and hydrocarbons, comprises a matrix of a type 5A zeolite molecular sieve and a kaolinite clay binder therefor, the clay binder having a concentration of at least 75% by dry weight of kaolinite and a maximum quartz concentration of 20% by dry weight.

Abstract: Adsorbent material well adapted for the purification of gases (notably by the PSA and TSA methods) by adsorbing impurities therefrom that are more polar or polarizable than the gases to be purified, e.g., nitrogen, the oxides of carbon and hydrocarbons, comprises a matrix of a type 5A zeolite molecular sieve and a kaolinite clay binder therefor, the clay binder having a concentration of at least 75% by dry weight of kaolinite and a maximum quartz concentration of 20% by dry weight.

Abstract: Impure gaseous silane containing such impurities as, in particular, phosphines and arsines, is purified, whether by chemisorption and/or physical adsorption, by contacting such silane gas with a sorption mass that includes cooper values, e.g., a copper cation-exchanged molecular sieve.