Abstract: NOx abatement compositions include cobalt oxide (Co3O4) doped with cerium, and having an overall formula Co3-xCexO4, with cerium occupying tetrahedral and/or octahedral sites in the spinel structure. The NOx abatement compositions possess NOx storage and NOx direct decomposition activity. Dual stage NOx abatement devices include an upstream portion having the NOx abatement composition to adsorb and store NOx at low temperature, and then release the NOx at higher temperature to a downstream catalytic conversion portion.

Abstract: NOx abatement compositions have a formula MxCu1-xFe2O4, wherein M is a substitution metal cation that can be any of cobalt, nickel, and zinc; and x is greater than zero and less than one. Such compositions can serve as direct decomposition catalysts and/or passive adsorption/storage components. Methods for synthesizing the compositions include alkaline precipitation of solutions containing nitrate salts of copper, iron, and at least one of cobalt, nickel, and zinc.

Abstract: A catalyst for direct decomposition of NO and NO2 to N2 and O2 has a CoFe2O4 spinel doped with potassium cations. The catalyst has high activity and good selectivity for N2 production, when potassium cations are loaded at a density of about 0.9 weight percent. Methods for making the catalyst include wet impregnation of a CoFe2O4 spinel with a solution of potassium cations, such as a KOH solution.

Abstract: A catalyst for direct decomposition of NO and NO2 to N2 and O2 has a CoFe2O4 spinel doped with potassium cations. The catalyst has high activity and good selectivity for N2 production, when potassium cations are loaded at a density of about 0.9 weight percent. Methods for making the catalyst include wet impregnation of a CoFe2O4 spinel with a solution of potassium cations, such as a KOH solution.

Abstract: Active catalysts for the treatment of a low temperature exhaust gas stream are provided containing palladium oxides dispersed on a spinel oxide for the direct, lean removal of nitrogen oxides from the exhaust gas stream. The low temperature (from about 400° C. to about 650° C.), direct decomposition is accomplished without the need of a reductant molecule. In one example, PdO may be dispersed on a surface of a metal oxide support, such as Co3O4 spinel oxide, synthesized using wet impregnation techniques. The PdO/Co3O4 catalyst system converts nitric oxide to nitrogen gas with high product specificity, avoiding the production of a significant concentration of the undesirable N2O product.

Abstract: Active catalysts for the treatment of a low temperature exhaust gas stream are provided containing potassium (K) dispersed on a spinel oxide for the direct, lean removal of nitrogen oxides from the exhaust gas stream. The low temperature (from about 400° C. to about 650° C.), direct decomposition is accomplished without the need of a reductant molecule. In one example, K may be dispersed on a surface of a metal oxide support, such as NiFe2O4 spinel oxide, synthesized using wet impregnation techniques. The K/NiFe2O4 catalyst system converts nitric oxide to nitrogen gas with high product specificity, up to 100%, avoiding the production of a significant concentration of the undesirable N2O product.

Abstract: Active catalysts for the treatment of a low temperature exhaust gas stream are provided containing potassium (K) dispersed on a spinel oxide for the direct, lean removal of nitrogen oxides from the exhaust gas stream. The low temperature (from about 400° C. to about 650° C.), direct decomposition is accomplished without the need of a reductant molecule. In one example, K may be dispersed on a surface of a metal oxide support, such as NiFe2O4 spinel oxide, synthesized using wet impregnation techniques. The K/NiFe2O4 catalyst system converts nitric oxide to nitrogen gas with high product specificity, up to 100%, avoiding the production of a significant concentration of the undesirable N2O product.

Abstract: Active catalysts for the treatment of a low temperature exhaust gas stream are provided containing palladium oxides dispersed on a spinel oxide for the direct, lean removal of nitrogen oxides from the exhaust gas stream. The low temperature (from about 400° C. to about 650° C.), direct decomposition is accomplished without the need of a reductant molecule. In one example, PdO may be dispersed on a surface of a metal oxide support, such as Co3O4 spinel oxide, synthesized using wet impregnation techniques. The PdO/Co3O4 catalyst system converts nitric oxide to nitrogen gas with high product specificity, avoiding the production of a significant concentration of the undesirable N2O product.

Abstract: Active catalysts for the treatment of a low temperature exhaust gas stream are provided for the direct decomposition removal of NOx from an exhaust gas stream. The catalyst system may include a mixed oxide composition including cerium oxide and nickel oxide CeO2—NiO. The exhaust gas stream may be provided at a temperature of from about 400° C. to about 650° C. Methods for making the catalyst include co-precipitation techniques, using KOH as a precipitating agent. The catalyst system is configured to catalyze a decomposition of the NOx to generate N2 without the presence of a reductant. The catalyst may be a cubic structure, with nickel incorporated in a cubic lattice of cerium. The catalyst composition may be represented as Ce0.5Ni0.5O2.