The present invention relates to a method of making a support material composition comprising an Mg/AI oxide, a cerium oxide and at least another rare earth element oxide, to a support material composition and to the use of the support material composition as a nitrogen oxide storage component within a catalyst for treating exhaust gases to reduce NOx content.

A low-temperature NO.sub.x storage catalyst for automobile exhaust purification and a preparation method thereof. Loading a noble metal salt solution on molecular sieve by equal volume impregnation method, wherein the noble metal salt solution comprises palladium nitrate and platinum nitrate, and the molecular sieve comprises SSZ, SAPO and BETA, then drying at 60-120° C. for 2-6 h, roasting at 500-550° C. in air for 2-5 h, and further roasting at 750-850° C. in air for 2-5 h, and then mixing with aluminum sol, ball milling and pulping, and then coating the slurry on a carrier, wherein the loading on the coating is 100-250 g/L and the noble metal content is 10-150 g/ft.sup.3, drying at 60-120° C. for 2-6 h, then roasting at 500-550° C. in air for 2-5 h, and further continuing roasting at 750-850° C. in air for 2-5 h, to obtain the catalyst. Loading the noble metals Pt and Pd into a pore channel of a molecular sieve improves NO.sub.x storage capacity of a catalyst at low temperatures, and selecting a different type of molecular sieve as an NO.sub.x storage unit and increasing a roasting temperature of a molecular sieve material on which Pt and Pd are loaded significantly increases NO.sub.x storage capacity.

A NOx adsorber catalyst for treating an exhaust gas from a diesel engine. The NOx adsorber catalyst comprises a first region comprising a NOx adsorber material comprising a first molecular sieve catalyst. The first molecular sieve catalyst comprises a first noble metal and a first molecular sieve, and the first molecular sieve contains the noble metal. The first molecular sieve has an STI Framework Type.

The present invention relates to a catalyst which comprises a carrier substrate of length L, which extends between a first end face a and a second end face b, and catalytically active material zones A, B and C of different composition, wherein—material zone A comprises palladium or palladium and platinum with a weight ratio of Pd:Pt>1, and cerium oxide, —material zone B comprises platinum or platinum and palladium with a weight ratio of Pt:Pd>1, and cerium oxide and/or cerium/zirconium mixed oxide, and—material zone C comprises platinum or platinum and palladium with a weight ratio of Pt:Pd>1, and a carrier oxide, and wherein—material zone B is arranged above material zone A, and—material zone C is arranged above material zone B, and, starting from the second end face b of the carrier substrate, extends over a length of up to 60% of the length L. The invention also relates to a catalyst arrangement containing said catalyst.

Various embodiments include methods for determining the efficiency of an SCR catalytic converter in a system including a nitrogen oxide sensor, and a metering device for a reducing agent arranged in an exhaust-gas duct, and an exhaust recirculation line with a recirculation valve disposed downstream of the SCR catalytic converter and feeding an intake region of the engine. The methods comprise: setting or identifying a quasi-steady-state operating state and an associated recirculation rate; adding a first quantity of reducing agent using the metering device; measuring a resulting first nitrogen oxide value using the sensor; adding a further predefined quantity, different from the first quantity; measuring the resulting nitrogen oxide values using the sensor; and determining the efficiency of the SCR catalytic converter based at least in part on the associated exhaust-gas recirculation rate and the measured nitrogen oxide values.

The present disclosure is directed to an emission treatment system for oxidation of hydrocarbons and carbon monoxide and for NO.sub.x abatement in an exhaust stream of a lean burn engine, the emission treatment system including a low-temperature NO.sub.x adsorber (LT-NA) that includes a molecular sieve impregnated with at least one PGM component positioned in fluid communication with the exhaust stream; and an oxidation catalyst that includes a refractory metal oxide support containing manganese impregnated with platinum positioned in fluid communication with the exhaust stream, each of the LT-NA and the oxidation catalyst being disposed on a substrate. The invention provides a catalyst article combining an oxidation catalyst with a LT-NA and a related method of treatment of an exhaust gas.

The present invention relates to the use of a material B containing palladium and platinum in a weight ratio of 2:3 to 10:1 for increasing the low-temperature storage of nitrogen oxides by means of a material A containing palladium and zeolite, wherein material A and material B are present on a carrier substrate of the length L, and wherein material A and material B are different from one another.

An exhaust gas purification catalyst is provided which can be more enhanced in NOx purification performance. An exhaust gas purification catalyst including a substrate, a NOx storage layer located over the substrate, an oxidation catalyst layer located over a part of the NOx storage layer, the part being located upstream in an exhaust gas flow direction, and a reduction catalyst layer located over a part of the NOx storage layer, the part being located downstream in an exhaust gas flow direction, wherein the NOx storage layer includes an oxidation catalyst including Pd or Pd and Pt, and a NOx storage material including at least one element selected from the group consisting of an alkali metal, an alkali earth metal and a rare-earth element, the oxidation catalyst layer includes an oxidation catalyst including Pt or Pt and Pd, the reduction catalyst layer includes a reduction catalyst including Rh, and a total content rate (mol %) of Pt and Pd based on a total content rate (100 mol %) of metal element(s) in the oxidation catalyst layer is higher than a total content rate (mol %) of Pt and Pd based on a total content rate (100 mol %) of metal elements in the NOx storage layer.

A method of treating an exhaust gas from an internal combustion engine comprising contacting the exhaust gas with a lean NO.sub.x trap catalyst is disclosed. The lean NO.sub.x trap catalyst comprises a first layer and a second layer.

Passive NO.sub.x adsorption (PNA) compositions have a formula Pd—NiFe.sub.2O.sub.4 wherein Pd represents a palladium component, such as palladium oxide, that is adsorbed on surfaces of the nickel ferrite. Such compositions can be synthesized by wet impregnation of nickel ferrite with a palladium salt, and exhibit efficient NO.sub.x adsorption at low temperature, with NO.sub.x desorption occurring predominantly at high temperature. Two-stage NO.sub.x abatement catalysts, effective under engine cold start conditions, include a PNA composition upstream from an NO.sub.x conversion catalyst.