Catalytic articles having a high porosity substrate containing platinum, palladium or a mixture thereof, in walls of the high porosity substrate and an SCR catalyst coating on a wall of the high porosity substrate are disclosed. The platinum, palladium or mixture thereof can be present in the wall of the high porosity support as a metal, or as a supported platinum, palladium or a mixture thereof. The catalytic articles are useful for selective catalytic reduction (SCR) of NOx in exhaust gases and in reducing the amount of ammonia slip. Methods for producing such articles are described. Methods of using the catalytic articles in an SCR process, where the amount of ammonia slip is reduced, are also described.

An exhaust gas purification system of the present disclosure includes a first exhaust gas purification device that purifies exhaust gas discharged from an internal combustion engine and a second exhaust gas purification device that additionally purifies the exhaust gas purified by the first exhaust gas purification device, wherein the exhaust gas is exhaust gas with a gaseous composition in which an amount of reducing agents is in excess compared to a stoichiometric gaseous composition and a gaseous composition in which an amount of oxidants is in excess compared to the stoichiometric gaseous composition are alternately switched between, the first exhaust gas purification device includes a three-way catalyst, and the second exhaust gas purification device includes an exhaust gas purification catalyst containing spinel-type MgAl.sub.xFe.sub.2.00−xO.sub.4.00 supporting particles on which Rh is supported, where 0.00<×≤1.50.

An after treatment method is disclosed. The after treatment method may include: operating an engine at a lean air/fuel ratio; calculating an amount of NH.sub.3 stored in an SCR catalyst; calculating an amount of NOx which will flow into the SCR catalyst; determining whether conversion to a rich air/fuel ratio is desired; calculating, when the conversion to the rich air/fuel ratio is desired, a rich duration for which the rich air/fuel ratio is maintained and a target air/fuel ratio; and operating the engine at the target air/fuel ratio for the rich duration.

There is provided an exhaust gas purification system that allows efficient purification of NOx present in exhaust gas emitted from an internal combustion engine. The exhaust gas purification system of the disclosure comprises a first exhaust gas purification device that purifies exhaust gas emitted from an internal combustion engine, wherein the atmosphere alternately switches between a reducing agent-excess atmosphere and an oxidizing agent-excess atmosphere with respect to the stoichiometric atmosphere, and a second exhaust gas purification device that further purifies the exhaust gas that has been purified by the first exhaust gas purification device, wherein the first exhaust gas purification device has a three-way catalyst, and the second exhaust gas purification device has an exhaust gas purifying catalyst that comprises an AMn.sub.2O.sub.4 spinel-type oxide support (A=Mg, Zn or Li) on which a precious metal is supported.

A NO.sub.x adsorber catalyst and its use in an emission treatment system for internal combustion engines, is disclosed. The NO.sub.x adsorber catalyst composition comprises a support material, one or more platinum group metals disposed on the support material, and a NO.sub.x storage material.

Provided are a novel form of AFX zeolite, a novel synthesis technique for producing pure phase small pore zeolites, a novel synthesis method for producing a zeolite with an increased Al pair content, a catalyst comprising the AFX zeolite in combination with a metal, and methods of using the same.

The invention relates to a composition for mineralising carbon dioxide and nitrogen oxide gases, which comprises a mixture of magnesium (between 1 and 25%), iron (between 1 and 23%), calcium monoxide (between 1 and 25%), titanium dioxide (between 0.1 and 11%) and silicon dioxide (between 16 and 75%), with a particle diameter between 100 nm and 4000 μm. The composition causes the mineralisation of carbon dioxide (CO.sub.2) and of the gaseous chemical compounds known as “nitrogen oxides” (NO.sub.x) in the atmosphere. This composition can be added or mixed as an additive in paints, dyes, resins and elastic polymers (gum and natural rubber) in parts with wear, and for any type of covering.

The present disclosure is directed to a method for treating a gaseous exhaust stream containing nitrogen oxides (NO.sub.x) from a diesel or lean-burn gasoline engine following a cold-start of the engine The method involves contact of the gaseous exhaust stream with at least a low temperature NO.sub.x adsorber (LT-NA) component. The LT-NA component includes a rare earth metal component, a platinum group metal (PGM) component, and a dopant. The present disclosure is also directed to a method of modulating a NO.sub.x adsorption/desorption profile of an LT-NA composition, a NO.sub.x desorption temperature range of an LT-NA composition, or both.

Fluid purification systems employing a monolithic composite photocatalyst to remove volatile organic compounds (VOCs) and/or pathogenic organisms are disclosed. Pairing of systems tuned to abate each of these materials are discussed in different configurations such as series and parallel, as well as combining systems to target both materials simultaneously. System configurations that allow a portion of the fluid stream to be purified are also disclosed as are configurations that allow regeneration of the photocatalyst. These features may be augmented by sensors that allow closed loop control of bypass and regeneration cycles in the systems.

In one aspect, the disclosure relates to an oxygen-deficient mixed metal perovskite having the formula Sr.sub.xA.sub.1-xFe.sub.yB.sub.1-yO.sub.3-δ, wherein A can be Ca, K, Y, Ba, La, Sm, or any combination thereof; wherein B can be Co, Cu, Mn, Mg, Ni, Ti, or any combination thereof; wherein x is from 0 to 1; wherein y is from 0 to 1; and wherein δ is from 0 to 0.7. Also disclosed are redox catalysts comprising the oxygen-deficient mixed metal perovskites and methods for chemical looping air separation, chemical looping CO.sub.2 splitting, and chemical looping alkane conversion using the disclosed catalysts.