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.

The present disclosure provides catalyst compositions and catalytic articles capable of storing and/or reducing nitrogen oxide (NO.sub.x) emissions in engine exhaust, catalyst articles coated with such compositions, and processes for preparing such catalyst compositions and articles. The catalyst compositions include copper and palladium co-exchanged zeolites. Further provided is a process for preparing such co-exchanged zeolites, an exhaust gas treatment system including the catalytic articles disclosed herein, and methods for reducing NO in an exhaust gas stream using such catalytic articles and systems.

The present invention relates to a catalyst comprising a carrier substrate of the length L, which extends between a first end face ‘a’ and a second end face ‘b’, and differently composed material zones A and B arranged on the carrier substrate, wherein material zone A comprises platinum and no palladium or platinum and palladium with a weight ratio of Pt:Pd of ≥1 and, material zone B comprises a copper containing zeolite having a Cu/Al ratio of 0.355 or higher.

A passive NOx absorber for treating an exhaust gas from a diesel engine is described. The passive NOx absorber comprises a first washcoat region comprising a zeolite catalyst, the zeolite catalyst comprising a noble metal and a zeolite having a SAR of 2-15.

Zeolite catalysts and systems and methods for preparing and using zeolite catalysts having the CHA crystal structure are disclosed. The catalysts can be used to remove nitrogen oxides from a gaseous medium across a broad temperature range and exhibit hydrothermal stable at high reaction temperatures. The zeolite catalysts include a zeolite carrier having a silica to alumina ratio from about 15:1 to about 256:1 and a copper to alumina ratio from about 0.25:1 to about 1:1.

Catalyst compositions and methods of preparation comprising: exchanging a rare earth element into a molecular sieve; incorporating a promoter metal into the molecular sieve; wherein the rare earth element exchanging step and the promoter metal incorporation step are performed as separate steps.

An exhaust gas purification catalyst device including a substrate and an SCR catalyst layer on the substrate, the substrate containing catalyst precious metal particles directly supported on the substrate, the catalyst precious metal particles containing Pt, and the catalyst precious metal particles having an average particle diameter of 30 to 120 nm inclusive.

The present invention relates to a zeolite comprising zinc and platinum, and to a catalyst containing said zeolites.

Catalyst compositions and methods of preparation comprising: preparing a promoter metal-molecular sieve catalyst composition comprising a promoter metal and a molecular sieve; and incorporating an iron salt into the promoter metal-molecular sieve catalyst composition.

The present disclosure generally provides a catalyst composition comprising a zeolite containing iron and/or copper with a reduced amount of extra-framework aluminum. The catalyst composition is useful to catalyze the reduction of nitrogen oxides in exhaust gas in the presence of a reductant.