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.

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.

Synergized Platinum Group Metals (SPGM) catalyst system for TWC application is disclosed. Disclosed SPGM catalyst system may include a washcoat that includes stoichiometric CuMn spinel structure, supported on doped ZrO.sub.2, and an overcoat that includes PGM, such as platinum (Pt) supported on carrier material oxides, such as alumina. SPGM catalyst system shows significant improvement in nitrogen oxide reduction performance under lean and also rich operating conditions. Additionally, disclosed SPGM catalyst system exhibits enhanced catalytic activity for carbon monoxide conversion. Furthermore, disclosed SPGM catalyst systems are found to have enhanced catalytic activity compared to PGM catalyst system, showing that there is a synergistic effect between PGM catalyst, such as Pt, and CuMn spinel within disclosed SPGM catalyst system, which help in activity and thermal stability of disclosed SPGM catalyst.

A catalyst for storing nitrogen oxides (NO.sub.x) in an exhaust gas from a lean burn engine comprising a NO.sub.x storage material and a substrate, wherein the NO.sub.x storage material comprises a NO.sub.x storage component and an NO oxidation promoter on a support material, wherein the NO oxidation promoter is manganese or an oxide, hydroxide or carbonate thereof.

A process for catalytically reducing N.sub.2O concentration by more than 90% in an off-gas stream containing more than 15 vol. % N.sub.2O, comprising the steps of a) adding a reducing agent and a fresh dilution gas and/or a recirculated gas to the off-gas stream to provide a diluted off-gas stream; b) introducing the diluted off-gas into a decomposing reaction of N.sub.2O in the diluted off-gas stream by reaction with the reducing agent in presence of a catalyst containing cobalt to N.sub.2 and O.sub.2; c) withdrawing a reacted outlet gas stream from step (b) having a temperature higher than 300 C. as the diluted off-gas stream introduced into step (b) due to exothermal decomposition of the N.sub.2O; and d) transferring heat from the outlet gas stream to the off-gas stream upstream step (b) and/or step (a) by indirect heat exchange.

Provided is an exhaust gas purification catalyst that suppresses phosphorus poisoning and improves long-term durability. The exhaust gas purification catalyst includes a phosphorus collection layer and a catalyst layer containing at least one precious metal element M.sup.p selected from the group consisting of Pt, Pd, and Rh, wherein the phosphorus collection layer is arranged on the upper layer side and/or the upstream side with respect to the catalyst layer; the phosphorus collection layer contains a composite oxide containing Al and an alkaline earth metal element M.sup.a that includes Mg and that may include at least one selected from the group consisting of Ca, Sr, and Ba, and having a cubic spinel structure belonging to the space group Fd-3m; the composite oxide has a M.sup.a/Al molar ratio in a range of 0.02 or more and 0.60 or less; and the composite oxide has a peak derived from the cubic spinel structure belonging to the space group Fd-3m of the composite oxide between a diffraction angle 2x.sub.M.sup.a.sub.O that is a position of a peak derived from an alkaline earth metal oxide M.sup.aO and a diffraction angle 2x.sub.Al2O3 that is a position of a peak derived from an aluminum oxide Al.sub.2O.sub.3 in an X-ray diffraction spectrum.