A three-way catalyst device (TWC) includes a first catalytic brick (FCB) and a second catalytic brick (SCB) downstream from the FCB. The FCB has a first washcoat applied to a first support body including ceramic and/or metal oxide particles, Pd particles, and Rh particles, and has at most 35 g/ft.sup.3 Pd and at most 7.5 g/ft.sup.3 Rh. The SCB has a second washcoat applied to a second support body including ceramic and/or metal oxide particles, Pt particles, and Rh particles, and has a Pt loading of at most 35 g/ft.sup.3 Pt and a Rh loading of at most 7.0 g/ft.sup.3 Rh. The FCB can have 25 g/ft.sup.3 to 35 g/ft.sup.3 Pd and 5.5 g/ft.sup.3 to 7.5 g/ft.sup.3 Rh and the SCB can have 25 g/ft.sup.3 to 35 g/ft.sup.3 Pt and 5.0 g/ft.sup.3 to 7.0 g/ft.sup.3 Rh. The TWC can receive exhaust gas from an internal combustion engine powering a vehicle.

An exhaust gas treatment system includes in order: an intake for receiving an exhaust gas from a lean burn combustion engine; an injector for the provision of a nitrogenous reductant; a close-coupled vanadium-containing SCR catalyst composition; one or more downstream PGM-containing oxidation catalyst compositions, wherein the close-coupled vanadium-containing SCR catalyst composition includes cerium in a Ce:V molar ratio of greater than 0.3.

A catalytic article for treating exhaust gas comprising: a first catalytic region beginning at the inlet end and extending for less than the axial length L, wherein the first catalytic region comprises a first palladium component and a first oxygen storage capacity (OSC) material comprising ceria; a second catalytic region beginning at the outlet end and extending for less than the axial length L, wherein the second catalytic region comprises a second palladium component and a second OSC material comprising ceria; a third catalytic region beginning at the outlet end and extending for less than the axial length L, wherein the third catalytic region comprises a third rhodium component and a third OSC material comprising ceria; wherein at least a portion of the first catalytic region is not covered by the second catalytic region and/or the third catalytic region; and wherein (a) the ceria amount in the first catalytic region is less than 50% of the total ceria amount in the first, second, and third catalytic regions; or (b) the ceria loading in the first catalytic region is less than 50% of the sum of the ceria loading in the first, second, and third catalytic regions.

A gasoline engine exhaust gas purification catalyst for purifying exhaust gas emitted from a gasoline engine includes a precious metal, alumina, and a ceria/zirconia composite oxide supported on a three-dimensional structure, and has pores having a peak 1 at a pore size of not less than 0.001 μm and not greater than 0.05 μm, pores having a peak 2 at a pore size of not less than 2.5 μm and not greater than 5.0 μm, and pores having a peak 3 at a different pore size than the above pore sizes in a pore size distribution measured by mercury intrusion method, wherein the pore volume of the pores having the peak 3 is greater than 1.4% of the total pore volume. A production method for the catalyst, and an exhaust gas purification method using the catalyst are also described.

Disclosed herein are emission treatment systems, articles, and methods for selectively reducing NOx compounds. The systems include a hydrogen generator, a hydrogen selective catalytic reduction (H.sub.2-SCR) article, and one or more of a diesel oxidation catalyst (DOC) and/or a lean NOx trap (LNT) and/or a low temperature NOx adsorber (LTNA). Certain articles may comprise a zone coated substrate and/or a layered coated substrate and/or an intermingled coated substrate of one or more of the H.sub.2-SCR and/or DOC and/or LNT and/or LTNA catalytic compositions.

A vehicular exhaust filter comprising a porous substrate having an inlet face and an outlet face with the porous substrate comprising inlet channels extending from the inlet face and outlet channels extending from the outlet face is disclosed. The inlet channels and the outlet channels are separated by a plurality of filter walls having a porous structure. The vehicular exhaust filter is loaded with a refractory powder having a tapped density before loading of less than 0.10 g/cm.sup.3 and the vehicular exhaust filter has a mass loading of the refractory powder of less than 10 g/l.

Systems for reducing the content of residual pollutants from tailpipes emissions in an exhaust line having a cold part may include an ozone generation system; an MnO.sub.2 catalyst; and a lean NO.sub.x trap (LNT) catalyst. In these systems, the ozone, MnO.sub.2 catalyst, and LNT catalyst may be provided in the cold part of the exhaust line. In these systems, the residuals pollutants may be oxidized at temperatures of from about 20° C. to about 150° C. in rich or lean conditions and NO.sub.2 may have a concentration of less than 0.1 mg/km in the tailpipe emissions downstream of the cold part of the exhaust line. Corresponding methods may include generating ozone from an ozonizer; injecting the ozone in a mixing chamber comprising the residual pollutants to form a first mixture; converting the first mixture using an MnO.sub.2 catalyst to form a second mixture; and converting the second mixture using an LNT catalyst.

Systems for reducing the content of residual pollutants from tailpipes emissions in an exhaust line having a cold part may include an ozone generation system; an MnO.sub.2 catalyst; and a lean NO.sub.x trap (LNT) catalyst. In these systems, the ozone, MnO.sub.2 catalyst, and LNT catalyst may be provided in the cold part of the exhaust line. In these systems, the residuals pollutants may be oxidized at temperatures of from about 20° C. to about 150° C. in rich or lean conditions and NO.sub.2 may have a concentration of less than 0.1 mg/km in the tailpipe emissions downstream of the cold part of the exhaust line. Corresponding methods may include generating ozone from an ozonizer; injecting the ozone in a mixing chamber comprising the residual pollutants to form a first mixture; converting the first mixture using an MnO.sub.2 catalyst to form a second mixture; and converting the second mixture using an LNT catalyst.

A vehicular exhaust filter comprising a porous substrate having an inlet face and an outlet face with the porous substrate comprising inlet channels extending from the inlet face and outlet channels extending from the outlet face is disclosed. The inlet channels and the outlet channels are separated by a plurality of filter walls having a porous structure. The vehicular exhaust filter is loaded with a refractory powder having a tapped density before loading of less than 0.10 g/cm.sup.3 and the vehicular exhaust filter has a mass loading of the refractory powder of less than 10 g/l.

A method and apparatus (1) for treating a filter (2) for filtering particulate matter from exhaust gas and a treated filter (2) are described. A reservoir (3) containing a dry powder (4) is provided. A vacuum generator (6) establishes a primary gas flow through a porous structure of the filter (2) by applying a pressure reduction to an outlet face of the filter (2). A spray device (7) receives the dry powder (4) from a transport device (8) and sprays the dry powder (4) towards the inlet face of the filter (2). A controller (9) is configured to control operation of at least the vacuum generator (6) and the spray device (7). The dry powder (4) comprises or consists of a metal compound for forming by thermal decomposition a metal oxide.