Synthesis of the silicoaluminophosphate and metal silicoaluminophosphate polymorphs of the molecular sieve SAPO-18 using cyclic quaternary ammoniums as organic structure-directing agents (OSDA) and use thereof as a catalyst.

There is provided a method for producing zeolite having a CHA structure in which Cu is carried, the method enabling an increase in ion exchange efficiency of Cu, effective utilization of Cu, and reduction in production cost. The method for producing the zeolite having the CHA structure in which Cu is carried includes a mixing step of mixing a powder of the zeolite having the CHA structure and a powder of Cu salt with each other and a heating step of heating the obtained powder mixture.

There is provided a zeolite having a CHA structure. When a total integrated intensity of a (211) plane, a (104) plane, and a (220) plane in an X-ray diffraction spectrum obtained by an X-ray powder diffraction method is defined as X.sub.0 and the total integrated intensity after heat endurance test for five hours at 900 C. under an air atmosphere is defined as X.sub.1, a ratio of X.sub.1 (X.sub.1/X.sub.0) to X.sub.0 is within a range from 0.2-0.7; and as measured by a .sup.27Al-NMR method after the heat endurance test for five hours at 900 C. under the air atmosphere, when a peak intensity of tetra-coordinated Al atoms is defined as P.sub.4 and a peak intensity of hexa-coordinated Al atoms is defined as P.sub.6, a ratio of P.sub.6 (P.sub.6/P.sub.4) to P.sub.4 is 0.1 or less.

A method for synthesizing a crystalline molecular sieve SSZ-13, characterized in that the method comprises bringing the following raw materials into contact in water under a crystallization condition: at least one tetravalent silicon source, at least one trivalent aluminum source, at least one alkali metal compound, choline cations and/or SSZ-13 seed crystals, and hydroxide ions. The method avoids using benzyl trimethyl quaternary ammonium ions (BzTMA.sup.+) or N,N,N-trimethyl-1-amantadine cations as structure-directing agents, and obtains high-quality crystal molecular sieve SSZ-13. Due to the use of a low-cost nontoxic structure-directing agent, the method has low production price by employing a low-cost nontoxic template, and can be popularized for application.

The present disclosure provides catalyst compositions for NO.sub.x conversion and wall-flow filter substrates comprising such catalyst compositions. Certain catalyst compositions include a zeolite with sufficient Cu exchanged into cation sites thereof to give a Cu/Al ratio of 0.1 to 0.5 and a CuO loading of 1 to 15 wt. %; and a copper trapping component (e.g., alumina) including a plurality of particles having a D.sub.90 particle size of about 0.5 to 20 microns in a concentration of about 1 to 20 wt. %. The zeolite and copper trapping component can be in the same washcoat layer or can be in different washcoat layers (such that the copper trapping component serves as a pre-coating on the wall-flow filter substrate).

A particle filter for treating exhaust gases includes an SCR catalyst that, when in the presence of a reductant such as ammonia, promotes selective catalytic reduction of NO.sub.x; an active oxidation catalyst that promotes oxidation of hydrocarbons and carbon monoxide; and an oxygen storage catalyst that alternately stores and releases oxygen, enhances soot oxidation, and stores NOx at temperatures below optimal SCR functioning. The particle filter may be included in a system having an oxidation catalytic device (OCD) upstream of the particle filter, and optionally includes one or more SCR converters upstream and/or downstream of the particle filter, and/or an ammonia slip catalyst downstream of the particle filter. The system may further be adapted for operation under a high frequency injection fuel control with an OCD having substantial NOx storage material content, or an NSC for improving the efficiency tradeoffs between soot oxidation during filter regeneration and NO.sub.x reduction.

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.

Provided is a catalyst washcoat comprising (i) a molecular sieve loaded with about 1 to about 10 weight percent of at least non-aluminum promoter metal (wherein the promoter metal weight percent is based on the weight of the molecular sieve); and (ii) about 1 to about 30 weight percent of a binder having a d90 particle size of less than 10 microns (wherein the binder weight percent is based on the total weight of the washcoat). In another aspect of the invention, the catalyst washcoat is applied to a wall-flow filter to form a catalyst article. In another aspect of the invention the catalyst article is part of an exhaust gas treatment system. And in yet another aspect of the invention, provided is a method for treating exhaust gas using the catalyst article.

An aftertreatment system for treating constituents of an exhaust gas generated by an engine includes: a selective catalytic reduction (SCR) system including a SCR catalyst; an oxidation catalyst disposed upstream of the SCR catalyst; and a controller configured to: determine an amount of SO.sub.x gases in the exhaust gas flowing through the aftertreatment system, and in response to the concentration of the SO.sub.x gases being above a threshold, cause heating of the SCR catalyst to an aging temperature in the presence of water to hydrothermally age the SCR catalyst.

The present disclosure provides catalyst compositions for NOx conversion and catalytic articles incorporating such catalyst compositions. Certain catalyst compositions include a zeolite with a silica-to-alumina ratio from 5 to 20 and sufficient Cu exchanged into cation sites of the zeolite such that the zeolite has a Cu/Al ratio of 0.1 to 0.5 and a CuO loading of 1 to 15 wt. %; and a copper trapping component in a concentration in the range of 1 to 20 wt. %, the copper trapping component including a plurality of particles having a particle size of about 0.5 to 20 microns. Certain catalyst compositions include, as the copper trapping component, alumina present as a plurality of alumina particles with a D.sub.90 particle size distribution in the range of 0.5 microns to 20 microns.