The present invention relates to a particulate filter, in particular a particulate filter for use in an emission treatment system of an internal combustion engine. The particulate filter provides an advantageous combination of low back pressure and high fresh filtration efficiency.

A catalyst composition for selective catalytic reduction of NO.sub.x by ammonia or compounds, such as urea, generating ammonia under exhaust gas conditions. The composition includes a) a copper ion exchanged zeolite particles having a Si/Al.sub.2 molar ratio (SAR) of 15 or less and a copper content sufficiently high to perform the catalytic reduction, b) a nanocrystalline aluminium compound in an amount sufficient for stabilizing the zeolite, and c) a zirconium compound in an amount sufficient to improve hydrothermal durability of the catalyst composition.

The present invention relates to the technical field of flue gas denitration catalysts, and discloses a hydrogenated TiO.sub.2 denitration catalyst and a preparation method and use thereof. The hydrogenated TiO.sub.2 denitration catalyst has a crystal form of anatase form, with oxygen vacancies and surface hydroxyl groups; wherein the hydrogenated TiO.sub.2 denitration catalyst contains TiO.sub.2, SO.sub.3 and P.sub.2O.sub.5, and based on the total weight of the hydrogenated TiO.sub.2 denitration catalyst, the content of TiO.sub.2 is 98-99.8% by weight, the content of SO.sub.3 is 0.2-1% by weight, and the content of P.sub.2O.sub.5 is 0.1-0.2% by weight. The hydrogenated TiO.sub.2 denitration catalyst has high denitration activity at 300-400° C. and N.sub.2 selectivity as high as 85% or more, and can be used in NH.sub.3—SCR denitration.

The present invention relates generally to the field of exhaust treatment systems for purifying exhaust gas discharged from a lean burn engine. The exhaust treatment system comprises a Diesel Oxidation Catalyst (DOC), a Catalyzed Soot Filter (CSF), a reductant injector, an AEI zeolite based Selective Catalyzed Reduction (SCR) catalyst and an Ammonia Oxidation Catalyst (AMOX) downstream to the AEI zeolite based SCR catalyst.

The moisture-resistant catalyst for air pollution remediation is a catalyst with moisture-resistant properties, and which is used for removing nitrogen compound pollutants, such as ammonia (NH.sub.3), from air. The moisture-resistant catalyst for air pollution remediation includes at least one metal oxide catalyst, at least one inorganic oxide support for supporting the at least one metal oxide catalyst, and a porous framework for immobilizing the at least one metal oxide catalyst and the at least one inorganic oxide support, where the porous framework is moisture-resistant. As non-limiting examples, the at least one metal oxide catalyst may be supported on the at least one inorganic oxide support by precipitation, impregnation, dry milling, ion-exchange or combinations thereof. The at least one metal oxide catalyst supported on the at least one inorganic oxide support may be physically embedded in the porous framework.

A cerium-zirconium-aluminum-based composite material, a cGPF catalyst and a preparation method thereof are provided. The cerium-zirconium-aluminum-based composite material adopts a stepwise precipitation method, firstly preparing an aluminum-based pre-treated material, then coprecipitating the aluminum-based pre-treated material with zirconium and cerium sol, and finally roasting at high temperature to obtain the cerium-zirconium-aluminum-based composite material. The cerium-zirconium-aluminum-based composite material has better compactness and higher density, and when it is used in cGPF catalyst, it occupies a smaller volume of pores on the catalyst carrier, such that cGPF catalyst has lower back pressure and better ash accumulation resistance, which is beneficial to large-scale application of cGPF catalyst.

An object of the present invention is to provide means for releasing oxygen at a temperature lower than conventional means in an exhaust gas purification catalyst. A Ce—Zr composite oxide is provided, which has a crystallite diameter of 6.5 nm or less and a BET specific surface area of 90 m.sup.2/g or more.

The present invention relates to a mixed oxide of aluminium, of zirconium, of cerium, of lanthanum and optionally of at least one rare-earth metal other than cerium and lanthanum that makes it possible to prepare a catalyst that retains, after severe ageing, a good thermal stability and a good catalytic activity. The invention also relates to the process for preparing this mixed oxide and also to a process for treating exhaust gases from internal combustion engines using a catalyst prepared from this mixed oxide.

An automotive catalytic converter includes a three-way catalyst having Rh as the only precious metal configured as a front zone and a three-way catalyst having a mixture of Rh and Pd, Pt, or both configured as a rear zone, such that an exhaust gas from an internal combustion engine passes through the front zone before passing through the rear zone to minimize sulfur poisoning of the catalytic converter.

Disclosed herein are compositions containing zirconium and cerium having a surprisingly small particle size. The compositions disclosed herein contain zirconium, cerium, optionally yttrium, and optionally one or more other rare earth oxides other than cerium and yttrium. The compositions exhibit a particle size characterized by a D.sub.90 value of about 5 μm to about 30 μm and a D.sub.99 value of about 5 um to about 40 um. Further disclosed are processes of producing these compositions using oxalic acid and supercritical drying in the process. The compositions can be used as a catalyst and/or part of a catalytic system. The composition is prepared by co-precipitation using oxalic acid and supercritical drying.