Abstract: A composite material includes a polymer matrix and a quantity of electrically conductive microparticles dispersed within the polymer matrix in an amount and distribution structured so that the composite material exhibits an increase in thermal emissivity of at least about 8% with increasing temperature of the composite material, for temperatures over a range of 23° C.-60° C. inclusive. The composite material may be used as (or as part of) a passive variable radiator for cooling an object in thermal communication with the composite material.

Abstract: An oxygen storage material (OSM) includes a zinc manganese iron oxide (ZMF) and an alkali metal base on the ZMF surface. The ZMF has a spinel structure. The alkali metal containing ZMF can be formed to have a weight percent of alkali metal up to about two percent. The alkali metal carbonate is retained on the ZMF surface upon heating to a temperature greater than 1,000° C. and stabilizes the ZMF to the cycling of an oxygen rich and oxygen lean atmosphere. The OSM additionally catalyzes the oxidation of hydrocarbons and CO and catalyzes the reduction of NOx for use in catalytic converters.

Abstract: Methods of making an iron based catalyst using microwave hydrothermal synthesis are provided. The methods include dissolving iron(III) nitrate, Fe(NO3)3, in an organic solvent to form a solution. Once dissolved, the methods include a step of neutralizing the solution with an alkaline mineralizing agent to obtain a precipitate. The solution with the precipitate is then subjected to microwave radiation to cause a temperature gradient and a hydrothermal crystallization process to form a synthesized product. The synthesized product is subsequently separated from the mineralizing agent. The method includes washing and drying the synthesized product to obtain particles of sodium iron oxide (NaFeO2) catalyst that can be used as a composition for a passive NOx adsorber. A two-stage NOx abatement device for removal of NOx from an exhaust gas stream during a cold start operation of an internal combustion engine is also provided.

Abstract: An oxygen storage material (OSM) includes a zinc manganese iron oxide (ZMF) and an alkali metal base on the ZMF surface. The ZMF has a spinel structure. The alkali metal containing ZMF can be formed to have a weight percent of alkali metal up to about two percent. The alkali metal carbonate is retained on the ZMF surface upon heating to a temperature greater than 1,000° C. and stabilizes the ZMF to the cycling of an oxygen rich and oxygen lean atmosphere. The OSM additionally catalyzes the oxidation of hydrocarbons and CO and catalyzes the reduction of NOx for use in catalytic converters.

Abstract: An improved catalyst system is provided for the direct decomposition removal of NOx from an exhaust gas stream at temperatures between about 350° C. and about 600° C. that employs an (amorphous CuOx)/Co3O4 catalyst. The catalyst has an amorphous CuOx deposit on the surfaces of particles of Co3O4 spinel oxide. The catalyst is configured to reduce NOx to N2 without the presence of a reductant. The (amorphous CuOx)/Co3O4 catalyst is formed by the precipitation of the deposit from solution onto a suspension of Co3O4 spinel oxide particles. The catalyst system can be employed in a catalytic converter for the direct decomposition removal of NOx from an exhaust gas stream flowing at a temperature of less than or equal to about 500° C.

Abstract: NOx abatement compositions include cobalt oxide (Co3O4) doped with cerium, and have an overall formula Co3-xCe-O4, 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: Passive NOx adsorption (PNA) compositions have a formula Pd—NiFe2O4 wherein Pd represents a palladium component, such as palladium oxide, that is adsorbed on surfaces of the nickel ferrite. Such compositions can be synthesized by wet impregnation of nickel ferrite with a palladium salt, and exhibit efficient NOx adsorption at low temperature, with NOx desorption occurring predominantly at high temperature. Two-stage NOx abatement catalysts, effective under engine cold start conditions, include a PNA composition upstream from an NOx conversion catalyst.

Abstract: An improved catalyst system is provided for the direct decomposition removal of NOx from an exhaust gas stream at temperatures between about 350° C. and about 600° C. that employs an (amorphous CuOx)/Co3O4 catalyst. The catalyst has an amorphous CuOx deposit on the surfaces of particles of Co3O4 spinel oxide. The catalyst is configured to reduce NOx to N2 without the presence of a reductant. The (amorphous CuOx)/Co3O4 catalyst is formed by the precipitation of the deposit from solution onto a suspension of Co3O4 spinel oxide particles. The catalyst system can be employed in a catalytic converter for the direct decomposition removal of NOx from an exhaust gas stream flowing at a temperature of less than or equal to about 500° C.

Abstract: Methods of making an iron based catalyst using microwave hydrothermal synthesis are provided. The methods include dissolving iron(III) nitrate, Fe(NO3)3, in an organic solvent to form a solution. Once dissolved, the methods include a step of neutralizing the solution with an alkaline mineralizing agent to obtain a precipitate. The solution with the precipitate is then subjected to microwave radiation to cause a temperature gradient and a hydrothermal crystallization process to form a synthesized product. The synthesized product is subsequently separated from the mineralizing agent. The method includes washing and drying the synthesized product to obtain particles of sodium iron oxide (NaFeO2) catalyst that can be used as a composition for a passive NOx adsorber. A two-stage NOx abatement device for removal of NOx from an exhaust gas stream during a cold start operation of an internal combustion engine is also provided.

Abstract: Passive NOx adsorption (PNA) compositions have a formula Pd—NiFe2O4 wherein Pd represents a palladium component, such as palladium oxide, that is adsorbed on surfaces of the nickel ferrite. Such compositions can be synthesized by wet impregnation of nickel ferrite with a palladium salt, and exhibit efficient NOx adsorption at low temperature, with NOx desorption occurring predominantly at high temperature. Two-stage NOx abatement catalysts, effective under engine cold start conditions, include a PNA composition upstream from an NOx conversion catalyst.

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: Active catalysts for the treatment of a low temperature exhaust gas stream are provided containing copper oxides dispersed on a spinel oxide for the direct, lean removal of nitrogen oxides from the exhaust gas stream. The low temperature, direct decomposition is accomplished without the need of a reductant molecule. In one example, CuOx may be dispersed as a monolayer on a metal oxide support, such as Co3O4 spinel oxide, synthesized using an incipient wetness impregnation technique. The CuOx/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: 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 containing copper oxides dispersed on a spinel oxide for the direct, lean removal of nitrogen oxides from the exhaust gas stream. The low temperature, direct decomposition is accomplished without the need of a reductant molecule. In one example, CuOx may be dispersed as a monolayer on a metal oxide support, such as Co3O4 spinel oxide, synthesized using an incipient wetness impregnation technique. The CuOx/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.