A NO.sub.x absorber catalyst for treating an exhaust gas from a lean burn engine. The NO.sub.x absorber catalyst comprises a molecular sieve catalyst comprising a noble metal and a molecular sieve, wherein the molecular sieve contains the noble metal; an oxygen storage material for protecting the molecular sieve catalyst; and a substrate having an inlet end and an outlet end.

The exhaust gas purification device includes: a substrate of wall flow structure having inlet cells, outlet cells and a porous partition wall; and a catalyst layer provided in at least part of internal pores of the partition wall and held on the surface of the internal pores. The relationship between an average filling factor A of the catalyst layer held in pores having a pore diameter of 5 m to less than 10 m, an average filling factor B of the catalyst layer held in pores having a pore diameter of 10 m to less than 20 m and an average filling factor C of the catalyst layer held in pores having a pore diameter of 20 m to less than 30 m, among the internal pores of the partition wall 16 in which the catalyst layer is held, satisfies the following expression: A<B<C.

Variations of ZPGM catalyst material compositions including doped CuMn spinel supported on doped zirconia support oxide are disclosed. The disclosed ZPGM catalyst compositions include a small substitution of Ni within the A-site or B-site cation of a CuMn spinel supported on doped zirconia support oxide, and produced by the incipient wetness (IW) methodology. Bulk powder ZPGM catalyst compositions are subjected to XRD analyses to determine the spinel phase formation and stability. Additionally, bulk powder ZPGM catalyst compositions are subjected to a steady-state isothermal sweep test to determine NO, CO, and THC conversion. The ZPGM catalyst material compositions including Ni-doped CuMn spinel supported on doped zirconia support oxide exhibit improved levels in NO and CO conversions, which can be employed in ZPGM catalysts for a plurality of TWC applications, thereby leading to a more effective utilization of ZPGM catalyst materials with high thermal and chemical stability in TWC products.

Sulfur-resistant synergized platinum group metals (SPGM) catalysts with significant oxidation capabilities are disclosed. Catalytic layers of SPGM catalyst samples are produced using conventional synthesis techniques to build a washcoat layer completely or substantially free of PGM material. The SPGM catalyst includes a washcoat layer comprising YMnO.sub.3 perovskite and an overcoat layer including a Pt composition deposited on a plurality of support oxides with total PGM loading of about 5 g/ft.sup.3. Resistance to sulfur poisoning and catalytic stability is observed under 1.3 gS/L condition to assess the influence that selected support oxides have on the DOC performance of the SPGM catalysts. The results indicate SPGM catalysts produced to include a layer of low amount of PGM catalyst material deposited on a plurality of support oxides added to a layer of ZPGM catalyst material are capable of providing significant improvements in sulfur resistance of SPGM catalyst systems.

In an example of a method for forming a catalyst, a polymeric solution including a platinum group metal (PGM) is exposed to electrospinning to form carbon-based nanofibers containing PGM nanoparticles therein. An outer surface of the carbon-based nanofibers containing the PGM nanoparticles is coated with a metal oxide or a metal oxide precursor. The carbon-based nanofibers are selectively removed to form metal oxide nanotubes having PGM nanoparticles retained within a hollow portion thereof.

The present disclosure describes ZPGM catalyst material compositions having significantly high oxygen storage capacity for a plurality of TWC applications. The disclosed ZPGM catalyst material compositions include a CuMn spinel deposited on doped Zirconia support oxide. The disclosed ZPGM catalyst material compositions exhibit significant high OSC stability properties after fuel cut aging. The improved thermal stability and OSC properties of the disclosed ZPGM catalyst material compositions are determined by performing a standard isothermal oscillating OSC tests. Fresh and aged ZPGM catalyst material compositions are employed within the standard isothermal oscillating OSC test, over multiple reducing/oxidizing cycles at a temperature of about 575 C.

The present disclosure describes bulk powder Zero-PGM material compositions including a CuMn.sub.2O.sub.4 spinel structure supported on doped zirconia support oxides powders, including Ba, Sr, and Ti at different dopant loadings produced by different conventional synthetic methods. BET-surface area and XRD analysis are performed for a plurality of doped zirconia support oxides to compare the thermal stability, before and after deposition of CuMn spinel. Additionally, bulk powder ZPGM catalyst compositions are subjected to a steady-state isothermal sweep test to determine NO conversion capabilities. The selected support oxide material compositions are capable of providing increased surface areas for improved thermal stability leading to a more effective utilization of ZPGM catalyst materials with enhanced NO conversion and improved thermal stability for TWC applications.

A zoned catalyzed substrate monolith comprises a first zone and a second zone that are arranged axially in series. The first zone comprises a platinum group metal loaded on a support and a first base metal oxide or a first base metal loaded on an inorganic oxide. The first base metal oxide is iron oxide, manganese oxide, copper oxide, zinc oxide, nickel oxide, or mixtures thereof. The first base metal is iron, manganese, copper, zinc, nickel, or mixtures thereof. The second zone comprises copper or iron loaded on a zeolite and a second base metal oxide or a second base metal loaded on an inorganic oxide. The second base metal oxide is iron oxide, manganese oxide, copper oxide, zinc oxide, nickel oxide, or mixtures thereof. The second base metal is iron, manganese, copper, zinc, nickel, or mixtures thereof. The second base metal is different from the first base metal.

Variations of coating processes of CuMnFe ZPGM catalyst materials for TWC applications are disclosed. The disclosed coating processes for CuMnFe spinel materials are enabled in the preparation ZPGM catalyst samples according to a plurality of catalyst configurations, which may include an alumina only washcoat layer coated on a suitable ceramic substrate, and an overcoat layer with or without an impregnation layer, including CuMnFe spinel and doped Zirconia support oxide, prepared according to variations of disclosed coating processes. Activity measurements are considered under variety of lean condition to rich condition to analyze the influence of disclosed coating processes on TWC performance of ZPGM catalysts for a plurality of TWC applications. Different coating processes may substantially increase thermal stability and TWC activity, providing improved levels of NO.sub.x conversion that may lead to cost effective manufacturing solutions for ZPGM-TWC systems.

A catalytic filter is provided having a mixture of an SCR catalyst and soot oxidation catalyst where the soot oxidation catalyst is a copper doped ceria, iron doped ceria or manganese doped ceria. The mixture of an SCR catalyst and soot oxidation catalyst provides for a lowering of the peak oxidation temperature for soot removal from the filter. The use of the filter allows for improved soot combustion and reduces the susceptibility of an SCR catalyst contained on a filter to deterioration. The soot oxidation catalyst also improves the resistance of the SCR catalyst to poisoning and subsequent deterioration of SCR performance.