748 results about "Cerium(IV) oxide" patented technology

A catalyst for treating exhaust gas from an internal combustion engine includes a carrier body coated with an inner layer and an outer layer. The inner layer includes platinum deposited on a first support material and on a first oxygen storage component, and the outer layer includes platinum and rhodium deposited on a second support material and on a second oxygen storage component. The first and second support materials may be the same or different, and may be selected from the group of: silica, alumina, titania, zirconia, mixed oxides or mixtures thereof, and zirconia-rich zirconia/ceria mixed oxide. The first and second oxygen storage components may include ceria-rich ceria/zirconia mixed oxide compounds, optionally including praseodymia, yttria, neodymia, lanthana or mixtures thereof.

The invention provides a high selectivity catalyst used for catalyzing and completely oxidizing formaldehyde with low concentration at room temperature. The catalyst can catalyze formaldehyde completely so as to lead the formaldehyde to be converted into carbon dioxide and water at room temperature. In addition, the conversion rate of formaldehyde remains 100% within a long period of time, without complex auxiliary facilities such as light source, a heating oven and the like, and external conditions. The catalyst comprises three parts which are inorganic oxide carrier, noble metal component and auxiliary ingredient. Porous inorganic oxide carrier is one of cerium dioxide, zirconium dioxide, titanium dioxide, aluminium sesquioxide, tin dioxide, silicon dioxide, lanthanum sesquioxide, magnesium oxide and zinc oxide or the mixture thereof or composite oxide thereof, zeolite, sepiolite and porous carbon materials. The noble metal component of the catalyst is at least one of platinum, rhodium, palladium, gold and silver. The auxiliary ingredient is at least one of the alkali metals of lithium, sodium, kalium, rubidium and cesium. The loading of the noble metal component used in the catalyst of the invention is 0.1 to 10% according to weight converter of metal elements and the selective preference is 0.3 to 2%. The loading of the auxiliary ingredient is 0.2 to 30% according to weight converter of metal elements and the selective preference is 1 to 10%. When the loading of the auxiliary ingredient is lower than 0.2% or higher than 30%, the activity of the catalyst for catalyzing and oxidizing formaldehyde at room temperature is decreased remarkably.

High-performance intermediate temperature solid oxide fuel cells (SOFCs). The SOFCs are ceria-based structures that can achieve a power output of 300 mW/cm.sup.2 at an operating temperature below 600.degree. C. By way of example, the fuel cell as an anode made of NiO/doped-ceria, a thin film of doped-ceria and/or doped zirconia electrolyte is deposited on the anode, and a cathode of cobalt iron based material, such as (La, Sr)(Co, Fe)O.sub.3 or cobalt, ion, magnesium based material, is deposited on top of the electrolyte, and can operate at a temperature of 550.degree. C. The various layers may be deposited by colloidal spray deposition or aerosol spray casting.

A single-layered three-way catalytic converter containing palladium as the only catalytically active noble metal, with high activity and heat resistance. The catalyst contains, in addition to finely divided, stabilized aluminum oxide, at least one finely divided cerium/zirconium mixed oxide and optionally finely divided nickel oxide as well as highly dispersed amounts of cerium oxide, zirconium oxide and barium oxide. The palladium is distributed largely uniformly throughout the entire catalyst.

A homogeneous ceria-based mixed-metal oxide, useful as a catalyst support, a co-catalyst and/or a getter, is described. The mixed-metal oxide has a relatively large surface area per weight, typically exceeding 150 m<2>/g, a structure of nanocrystallites having diameters of less than 4 nm, and including pores larger than the nanocrystallites and having diameters in the range of 4 to about 9 nm. The ratio of the pore volumes, VP, to skeletal structure volumes, VS, is typically less than about 2.5, and the surface area per unit volume of the oxide material is greater than 320 m<2>/cm<3>, such that the structural morphology supports both a relatively low internal mass transfer resistance and large effective surface area for reaction activity of interest. The mixed metal oxide is made by co-precipitating a dilute metal salt solution containing the respective metals, which may include Zr, Hf, and/or other metal constituents in addition to Ce, replacing water in the co-precipitate with a water-miscible low surface-tension solvent, and relatively quickly drying and calcining the co-precipitate at moderate temperatures. A highly dispersive catalyst metal, such as Pt, may be loaded on the mixed metal oxide support from a catalyst-containing solution following a selected acid surface treatment of the oxide support. The mixed metal oxide, as catalyst support, co-catalyst or getter, is applied in various reactions, and particularly water gas shift and/or preferential oxidation reactions as associated with fuel processing systems, as for fuel cells and the like.

A metal oxide nanorod array structure according to embodiments disclosed herein includes a monolithic substrate having a surface and multiple channels, an interface layer bonded to the surface of the substrate, and a metal oxide nanorod array coupled to the substrate surface via the interface layer. The metal oxide can include ceria, zinc oxide, tin oxide, alumina, zirconia, cobalt oxide, and gallium oxide. The substrate can include a glass substrate, a plastic substrate, a silicon substrate, a ceramic monolith, and a stainless steel monolith. The ceramic can include cordierite, alumina, tin oxide, and titania. The nanorod array structure can include a perovskite shell, such as a lanthanum-based transition metal oxide, or a metal oxide shell, such as ceria, zinc oxide, tin oxide, alumina, zirconia, cobalt oxide, and gallium oxide, or a coating of metal particles, such as platinum, gold, palladium, rhodium, and ruthenium, over each metal oxide nanorod. Structures can be bonded to the surface of a substrate and resist erosion if exposed to high velocity flow rates.

Electrode materials systems for planar solid oxide fuel cells with high electrochemical performance including anode materials that provide exceptional long-term durability when used in reducing gases and cathode materials that provide exceptional long-term durability when used in oxygen-containing gases. The cathode materials comprise zinc-doped lanthanum strontium ferrite (LSZF) or an alternative ferrite, cobaltite or nickelate ceramic electrode material. The cathode material also may comprise a mixed-conducting ceria-based electrolyte material, a palladium dopant, or a combination of these. The cathode may have a bi-layer structure. A ceramic-based interfacial layer may be provided at the electrolyte/cathode interface. The multilayer cathode system and its palladium doped cathode material exhibit a high degree of tolerance to chromium contamination during operation with metallic interconnect materials.

A thermal barrier coating system on a base material includes a bond coat layer with a lower face in direct contact with the base material and an upper face, a first ceramic layer in direct contact with the upper face of the bond coating layer and a second ceramic layer disposed on an outermost surface of the coating system and configured to be exposed to hot gas. The first ceramic layer includes a layer, combination, mixture, alloy, blend or multilayer structure of at least one of yttria-stabilized zirconia with a yttria content in a range of 6-8 wt-%, YTaO4 doped zirconia, and titania doped zirconia. The second ceramic layer includes a layer, combination, mixture, alloy, blend or multilayer structure of at least one of YTaO4 doped zirconia, titania doped zirconia, scandia stabilized zirconia, ceria containing perovskite material, yttrium aluminium garnet material, Monazite material, and spinel material. A material of the second ceramic layer is different from a material of the first ceramic layer.

The object of the invention is to provide an exhaust gas purifying catalyst having a high oxygen storage capacity without changing the usage amount of the oxygen storage component. According to the present invention, the exhaust gas purifying catalyst containing (a) a ceria-zirconia composite oxide containing ceria in a higher amount than zirconia, (b) a ceria-zirconia composite oxide containing zirconia in a higher amount than ceria, and (c) a ceria-zirconia composite oxide having a pyrochlore-type regular array structure is provided. The exhaust gas purifying catalyst of the present invention has a higher oxygen storage capacity than conventional catalysts and is effective in reducing the amount of NOx emission.

A ceramic anode structure obtainable by a process comprising the steps of: (a) providing a slurry by dispersing a powder of an electronically conductive phase and by adding a binder to the dispersion, in which said powder is selected from the group consisting of niobium-doped strontium titanate, vanadium-doped strontium titanate, tantalum-doped strontium titanate, and mixtures thereof, (b) sintering the slurry of step (a), (c) providing a precursor solution of ceria, said solution containing a solvent and a surfactant, (d) impregnating the resulting sintered structure of step (b) with the precursor solution of step (c), (e) subjecting the resulting structure of step (d) to calcination, and (f) conducting steps (d)-(e) at least once.

Disclosed herein is a three-way conversion (TWC) catalyst containing little or no rhodium for purifying exhaust gases of an internal combustion engine, having a multi-layers structure, including a lower layer including an alumina support and an oxygen storage material; an intermediate layer including alumina support impregnated only with palladium and a zirconia-rich oxygen storage material; and an upper layer including alumina support impregnated with platinum, minimum rhodium and platinum, or platinum-palladium and a ceria-rich oxygen storage material.

A CMP oxide slurry includes an aqueous solution containing abrasive particles and two or more different passivation agents. Preferably, the aqueous solution is made up of deionized water, and the abrasive particles are a metal oxide selected from the group consisting of ceria, silica, alumina, titania, zirconia and germania. Also, a first passivation agent may be an anionic, cationic or nonionic surfactant, and a second passivation agent may be a phthalic acid and its salts. In one example, the first passivation agent is poly-vinyl sulfonic acid, and the second passivation agent is potassium hydrogen phthalate. The slurry exhibits a high oxide to silicon nitride removal selectivity.

Described is a method for the production of metal oxides, in particular mixed metal oxides such as ceria/zirconia, and metal oxides obtainable by said method. Due to high enthalpy solvents with a high carboxylic acid content said metal oxides have improved properties. For example ceria/zirconia has excellent oxygen storage capacity at high zirconium levels up to more than 80% of whole metal content.

A process for producing a ceria-zirconia-alumina composite oxide is disclosed. The process comprises combining a cerium (IV) compound and a zirconium (IV) compound with a slurry of aluminum oxide at a temperature greater than 40° C. to produce a reaction slurry, then contacting the reaction slurry with a precipitating agent to precipitate insoluble cerium and zirconium compounds onto the aluminum oxide and form cerium-zirconium-aluminum oxide particles, and calcining the cerium-zirconium-aluminum oxide particles to produce a ceria-zirconia-alumina composite oxide. The process to produce ceria-zirconia-alumina composite oxides provides a material having a high oxygen storage/release capacity that is suitable for a catalyst with enhanced cleaning of the exhaust gases from internal combustion engines.

A ceria-zirconia base composite oxide contains a composite oxide of ceria and zirconia. In the ceria-zirconia base composite oxide, a content ratio between cerium and zirconium in the composite oxide is in a range from 43:57 to 48:52 in terms of molar ratio ([cerium]: [zirconium]). An intensity ratio of a diffraction line at 2θ=14.5° to a diffraction line at 2θ=29° {I(14/29) value} and an intensity ratio of a diffraction line at 2θ=28.5° to the diffraction line at 2θ=29° {I(28/29) value}, which are calculated from an X-ray diffraction pattern obtained by an X-ray diffraction measurement using CuKa after heating under a temperature condition of 1100° C. in air for 5 hours, respectively satisfy the following conditions:

I(14/29)value≧0.015, and I(28/29)value≦0.08.

The invention relates to a cobalt-cesium oxide catalyst for purifying carbon particles and a preparation method thereof, in particular to a catalyst for treating motor vehicle tail gas pollution, especially for treating the carbon particles from diesel vehicle tails gas, as well as the preparation method thereof. The catalyst is a double-oxide composite catalyst, in particular a catalyst which consists of cobalt loaded on nano cerium dioxide or bulk phase mixed oxide of the cobalt and the cesium, and does not contain precious metal components. The catalyst is nano particles and is suitable for processing the carbon particles in the diesel vehicle tail gas; and the minimum combustion peak temperature reaches 364 DEG C under the condition that the catalyst loosely contacts the carbon particles, which corresponds to the catalytic combustion activity of the carbon particles and the loaded precious metal catalyst.

The present invention relates to metal oxide particles having cores comprising larger molar amounts of zirconia than of ceria, and surface layers comprising larger molar amounts of ceria than of zirconia. Further, the present invention relates to a method for preparing the particles. The method comprises preparing a solution comprising zirconia sol and ceria sol, adjusting the pH of the solution within ±0.5 on the basis of the isoelectric point of zirconia, and aggregating zirconia and then aggregating ceria around the aggregated zirconia from the solution to make aggregates. Furthermore, the present invention relates to an exhaust gas purifying catalyst comprising the metal oxide particles, and a noble metal carried by the metal oxide particles.