Mixed valent manganese-based NOx adsorber

Abstract

Herein disclosed are compositions for passive NOx adsorption and oxidation that include at least a manganese-based oxide and one or more promoter materials and methods for making and using said compositions. The promotor materials may include a rare earth, transition, or main group metal. The compositions may be used in NOx emission control system and adsorbs NOx compounds at low temperatures and then release NOx at higher temperatures, where the NOx can be oxidized, without the hybridized MnOX composition breaking down. The compositions are capable of maintaining a sufficiently large surface area at high temperatures found in the emissions gas streams of internal combustion engines necessary for the complete elimination of NOx.

Claims

1. A composition of matter comprising: a first promoter, comprising one of: aluminum (Al), barium (Ba), cerium (Ce), lanthanum (La), copper (Cu), iron (Fe), magnesium (Mg), titanium (Ti), yttrium (Y), zirconium (Zr), and zinc (Zn); a second promoter, comprising one of: aluminum (Al), barium (Ba), cerium (Ce), lanthanum (La), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), titanium (Ti), yttrium (Y), zirconium (Zr), and zinc (Zn), but different from the first promoter; a manganese oxidizer; and oxygen, according to the formula A.sub.aB.sub.bMn.sub.yO.sub.x, wherein A is the first promoter, B is the second promoter, the additive value of a, b, and y is 1, a is in a range of 0.05-0.25, b is in a range of 0.05-0.25, and y is in a range of 0.50-0.90, x is selected to balance the valences of the formula, wherein said composition exhibits a NOx adsorption value of greater than 70 micromoles of NOx per gram at 300° C., and wherein the composition does not contain platinum group metals.

2. The composition of claim 1, wherein the Mn.sub.yO.sub.x component is 50-70 wt % of the composition.

3. The composition of claim 1, wherein said composition exhibits a specific surface area of between 150 square meters per gram and 250 square meters per gram at room temperature.

4. The composition of claim 1, wherein said composition exhibits a NOx adsorption value of greater than 50 micromoles of NOx per gram at 100° C.

5. The composition of claim 1, wherein said composition exhibits a pore diameter between 5 nanometers and 20 nanometers.

6. The composition of claim 1, wherein said composition exhibits a pore volume between 0.3 mL/g and 0.5 mL/g.

7. The composition of claim 1, wherein said composition exhibits sulfur content below 0.5%.

8. The composition of claim 1, wherein said composition does not produce N.sub.2O in an exhaust gas stream in a temperature range of 100 to 350° C.

9. The composition of claim 1, wherein said composition, when in an exhaust gas stream with a temperature range of 200 to 350° C., is either adsorbing or releasing NOx continuously.

10. The composition of claim 1, wherein said composition has a total alkali metal content of less than 3%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A better understanding of the present disclosure can be obtained with the following detailed descriptions of the various disclosed embodiments in the drawings, which are given by way of illustration only, and thus are not limiting the present disclosure, and wherein:

(2) FIG. 1 is a flow chart of a method of manufacturing a manganese oxide-based catalyst according to one embodiment of the present disclosure;

(3) FIG. 2 is another flow chart of another method of manufacturing a manganese oxide-based catalyst according to another embodiment of the present disclosure; and

(4) FIG. 3 is another flow chart of another method of manufacturing a manganese oxide-based catalyst according to another embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE DISCLOSURE

(5) The present disclosure is susceptible to embodiments of different forms. There are shown in the drawings, and herein will be described in detail, specific embodiments with the understanding that the present invention is to be considered an exemplification of the principles and is not intended to limit the present invention to that illustrated and described herein.

(6) The present invention concerns a composition comprising at least a manganese-based mixed oxide comprising manganese (Mn) and, optionally, at one or more promoter elements (A, or B), where the promoter element (A, B, C . . . ) or elements may be one or more of: aluminum (Al), barium (Ba), cerium (Ce), lanthanum (La), copper (Cu), iron (Fe), magnesium (Mg), titanium (Ti), yttrium (Y), zirconium (Zr), and zinc (Zn). The oxidation state of the central manganese atom in the final composition can be any of: Mn.sup.+2, Mn.sup.+3, or Mn.sup.+4, and the number of oxygen (O) components may vary.

(7) The A.sub.aB.sub.bMn.sub.yO.sub.x material may exhibit a specific surface area (SBET) of >200 square meters per gram after the first calcination and a specific surface area (SBET) of >10 square meters per gram after the ageing at 950° C. for about 1 to 4 hours. The material may exhibit a low temperature (100° C.) NOx adsorption value of >50 micromoles NOx per gram after aging at 650° C. and a total (300° C.) NOx adsorption value of >70 micromoles NOx per gram after aging at 650° C.

(8) More specifically, in some embodiments, the material may exhibit a low temperature (100° C.) NOx adsorption value of >80 micromoles NOx per gram after aging at 650° C. and a total (300° C.) NOx adsorption value of >90 micromoles NOx per gram after aging at 650° C.

(9) A.sub.aB.sub.bMn.sub.yO.sub.x is resistant to temperatures in the combustion exhaust stream in the range of 650-800° C. without significant change of catalytic activity and performance.

(10) This disclosure also shows methods of manufacturing A.sub.aB.sub.bMn.sub.yO.sub.x material. These methods may include steps involving specific sequences of co-precipitation, redox precipitation, pH, precipitation, ion-exchange methods, hydrothermal methods, sol-gel methods, template methods, acid washing, calcining, and thermal methods.

Definitions

(11) Throughout the description, including the claims, the term “comprising one” should be understood as being synonymous with the term “comprising at least one”, unless otherwise specified, and “between” should be understood as being inclusive of the limits.

(12) The NOx storage capacity is defined as the number of NOx molecules (in micromole of NOx per gram of catalyst) being adsorbed over the samples in the isothermal region at 100° C. for the first 15 min. Additional adsorption may take place at higher than 100° C. temperature. The NO oxidation is defined as the number of NO molecules contained in the incoming exhaust gas stream that has been oxidized to NO.sub.2. NOx storage and catalytic performance may be measured by flowing a synthetic gas mixture containing: 200 ppm NO, 211 ppm CO, 165 ppm C.sub.3H.sub.8, 5% CO.sub.2, 5% H.sub.2O, and 11.6% O.sub.2 at a Gas Hourly Space Velocity (GHSV) of 50,000 h.sup.−1 through the material. The temperature in a powder reactor may be held at 100° C. for the first 15 minutes followed by a 10° C. per minute temperature ramp up to 500° C.

(13) It is specified that, in the continuation of the description, unless otherwise indicated, the values at the limits are included in the ranges of values which are given. The proportions for the gases and the mixtures of gases are given in vol % and ppm. The volume flow rates and the vol % are given at 1 atmosphere and 20° C. Specifying any range of concentrations, any listed upper bound of a concentration range can be associated with any listed lower bound of a concentration range.

(14) The contents are given as the molar ratio of the cations which sum to one, unless otherwise indicated. Oxide refers there to final mixed oxide defined as integration of various element oxides composing the composition.

(15) The term “consisting of” means the embodiment necessarily includes the listed components and may also include additional unrecited oxide elements such as impurities, which may specifically originate from its preparation method, for example raw materials or starting reactants used, notably in an amount less than 2% by weight, more preferably less than 1% by weight, of the total mixed oxide. Proportions of impurities may be determined using the inductively coupled plasma mass spectrometry (ICPMS), atomic spectrophotometry, inductively coupled plasma emission spectroscopy (ICPOES), x-ray fluorescence spectroscopy or other techniques known to persons of skill in the art.

(16) In the continuation of the description, the term “specific surface area” is understood to mean the BET specific surface area determined by nitrogen adsorption in accordance with standard ASTM D 3663-78 laid down from the Brunauer-Emmett-Teller method described in the periodical “The Journal of the American Chemical Society, 60, 309 (1938)”. Specific surface areas are expressed for a designated calcination temperature and time.

(17) The calcinations, at the end of which the surface area values are given, are calcinations in air unless otherwise specified. Furthermore, the specific surface area values which are indicated for a given temperature and a given time correspond, unless otherwise indicated, to calcinations at a temperature held over the time indicated.

(18) A rare earth element (REE) or rare earth metal (REM), as defined by IUPAC, is one of a set of seventeen chemical elements in the periodic table, specifically the fifteen lanthanides, as well as scandium and yttrium. Rare earth elements are cerium (Ce), dysprosium (Dy), erbium (Er), europium (Eu), gadolinium (Gd), holmium (Ho), lanthanum (La), lutetium (Lu), neodymium (Nd), praseodymium (Pr), promethium (Pm), samarium (Sm), scandium (Sc), terbium (Tb), thulium (Tm), ytterbium (Yb) and yttrium (Y).

(19) The mixed valent passive NOx adsorber with a general formula of A.sub.aB.sub.bMn.sub.yO.sub.x, where a+b+y=1 and x is the value of oxygen required to balance the valences of the formula. The composition may include:

(20) 50-90 mol % of manganese;

(21) 5-25 mol % of at least one promoter from the list of aluminum (Al), barium (Ba), cerium (Ce), lanthanum (La), copper (Cu), iron (Fe), magnesium (Mg), titanium (Ti), yttrium (Y), zirconium (Zr), and zinc (Zn); and

(22) 5-25 mol % of second promoter from the list of aluminum (Al), barium (Ba), cerium (Ce), lanthanum (La), copper (Cu), iron (Fe), magnesium (Mg), titanium (Ti), yttrium (Y), zirconium (Zr), and zinc (Zn). In some embodiments, the first and the second promoter may be the same, in which case a single promoter material may have a range of 10-50 mol %.

(23) These elements are generally present as oxides. However, it is not excluded that they may be present at least partly in the form of hydroxides or oxyhydroxides. The proportions of these elements can be determined using standard analytical techniques, such as x-ray diffraction analysis and the active oxygen method. Preferably manganese is manganese oxide, and the promoter is a metal selected as described above other than manganese oxide.

(24) In some embodiments, the composition may be manganese oxide 50-70 wt %. In some embodiments, the ratio of manganese oxide to promoter(s) is about 1 to 0.2-0.3. Some exemplary, but not limiting, embodiments include Al.sub.0.1Ce.sub.0.2Mn.sub.0.7O.sub.x, Zr.sub.0.2Ce.sub.0.1Mn.sub.0.7O.sub.x, and Zr.sub.0.25Al.sub.0.25Mn.sub.0.5O.sub.x.

(25) In some embodiments, the promoter may be an oxide as well. For example, manganese combined with yttrium, could be manganese oxide with yttrium or manganese oxide with yttrium oxide.

(26) The mixed oxides of the present disclosure have specific properties, such as one or more of: 1) specific surface areas measured at room temperature ranging from 150 m.sup.2/g to 250 m.sup.2/g; 2) adsorption values ranging from 40 micromoles/g to 70 micromoles/g; 3) average pore diameters of between 5 nm and 20 nm; and 4) total pore volumes of between 0.3 mL/g and 0.5 mL/g.

(27) The total pore volume and pore diameter may be measured by ordinary N.sub.2 porosimetry. It mainly consists in a gas adsorption method determination of pore size distribution, using capillary condensation phenomenon and the principle of equivalent substitution volume.

(28) Specific surface area may be measured using BET surface area instrumentation or other suitable equipment in accordance with standard industry practices. Adsorption may be measured using a Horiba SA-6000 Series Surface Area Analyzer or other suitable equipment in accordance with standard industrial practices. Pore size may be measured using Micromeritics Tri Star II 3020 Automatic Physisorption Analyzer or other suitable equipment in accordance with standard industrial practices. Pore volume may be measured using Micromeritics TriStar II 3020 or other suitable equipment in accordance with standard industrial practices.

(29) Catalyst performance may be measured to confirm one or more of the above properties. The samples may be aged in moist air (2% vol H.sub.2O) at 650° C. for 16 hours in a horizontal tube furnace, or equivalent. Then, the samples may be transferred into a powder plug-flow reactor. In one example, 0.21 g of as-aged samples is loaded into a quartz tube reactor and diluted with sand (typically with a 1:1 ratio) to ensure 50,000 GHSV. First, a gas mixture containing 5% CO.sub.2, 5% H.sub.2O, and 11.6% O.sub.2 balanced with nitrogen may be used to precondition the samples. A heating ramp of 10° C./min is applied to reach 500° C. and then kept for 15 min at maximum temperature. The sample is allowed to cool to 100° C. A reactive gas mixture is set to 201 ppm NO, 211 ppm CO, 165 ppm C.sub.3Hg, 5.0% CO.sub.2, 5% H.sub.2O, and 11.0% O.sub.2 balanced with nitrogen while bypassing the reactor. Then, the reactive gas mixture is abruptly switched to the reactor. The adsorption of NOx is followed by Thermo-Fischer 42 iHL NOx analyzer. After the first 15 minutes, a heating ramp of 10° C./min is applied from 100° C. to 500° C. to induce temperature programmed NO oxidation. NOx storage capacity is measured at 100° C. Total NOx capacity is measured (additional adsorption may take place at higher temperature) at 300° C. NO oxidation is also measured at 300° C.

(30) Further, the composition may release NOx for catalysis at temperatures of about 50° C. to about 800° C. without decomposing. The composition does not produce N.sub.2O when in an exhaust gas stream in a temperature range of 100 to 350° C.

(31) Further, the composition, after aging at 950° C. for 16 hours and testing for oxygen storage capacity at 500° C., may store and release greater than 500 micromoles oxygen per gram material.

(32) Methods of Manufacture

(33) FIG. 1 shows a method 100 of manufacturing an embodiment of a hybridized MnOX composition according to the present disclosure. In step 110, a solution including a manganese salt, a first promoter and an optional second promoter may be prepared. The manganese salt has a lower valence of either +2 or +3. In some embodiments, an acid, such as nitric acid, may be added to place the manganese sale, the first promoter, and the optional second promoter into solution.

(34) In this case, chlorides, sulfates, hydroxides, oxides, carbonates or nitrates of the following elements: aluminum (Al), barium (Ba), cerium (Ce), lanthanum (La), copper (Cu), iron (Fe), potassium (K), magnesium (Mg), titanium (Ti), yttrium (Y), zirconium (Zr), and zinc (Zn) may be used as the first and second promoters. The solution is comprised of a manganese salt is mixed with at least one promoter salt in the required molar ratios in water. The amount of water used may be adjusted to have an intermediate solids content of 3.5 to 5.5% by mass in slurry as calculated as oxides. Mineral acids may be added to aid in the dissolution of the reactant salts, such as nitric acid, sulfuric acid, hydrochloric acid and other suitable inorganic acids known to persons of skill in the art. The solution is continuously mixed to ensure complete dispersion of the reactants. The temperature of the solution may be maintained between 20° C. to 80° C. prior to the synthesis of an intermediate product.

(35) In step 120, an oxidizer, such as a manganate salt, permanganate salt, or hydrogen peroxide is added to the solution in the appropriate ratio to attain the desired final oxidation state of the products, over a period of 30 minutes to three hours. The product may be washed after the time period in solution is complete.

(36) In step 130, a base, such as sodium hydroxide, potassium hydroxide, ammonium hydroxide, sodium bicarbonate or sodium carbonate may be added over a period of 30 minutes to three hours in the appropriate quantity to fully precipitate the non-oxidizable reactant metals and to attain a final slurry pH in the range of 7.5 to 10.0. Steps 120 and 130 may be performed alternately, sequentially or concurrently, and the oxidizer and the base may be added to the solution as a solid or in aqueous form to produce a slurry.

(37) In optional step 135, a surface modifying agent that will react with the precipitated material to preserve structure, diameter, and surface area of the pores of the precipitate during the later heating or aging steps may be added to the solution. Surface modifying agents may include organic compounds that react rapidly during heating or aging of the precipitate. The surface modifying agent may include one or more of: short chain organic acids, polyols, sugars, polyvinyl alcohol, polyethylene glycol-200, simple alcohols, and organic surfactants. When heated or aged, the surface modifying agent may modify the crystal structure and materials morphology and pore structure of the precipitate in solution to enhance its activity.

(38) In step 140, the slurry may be mixed and/or heated to improve uniformity of the mixture. The temperature during the synthesis step may be increased to between 40° C. and 80° C. for subsequent aging. A static mixer and a tank reactor are used at the same time to produce a mixed metal oxide via a redox precipitation method. The use of a Continuous Stirred Tank Reactor (CSTR) allows for a more complete and uniform reaction.

(39) Solids Separation

(40) Aging

(41) In step 150, the slurry may be aged. It is common to retain the solids slurry at the precipitation temperature and pH for a period ranging from about 10 minutes to about 6 hours depending on the composition of the solution. During aging, one or more organic surfactants, such as polyvinyl alcohol (PVA) polyvinyl amine, polyethylene glycol-200 (PEG 200), triton X-100, isopropyl alcohol and ethanol may be used to enlarge pore structure. The dosage is 0.1% to 10%. In some embodiments, the dosage may be 1% to 5%.

(42) Separation of Solid-Liquid

(43) In step 160, a precipitate may be separated from the solution after aging, which is the intermediate product. The precipitate in the slurry should be separated from the salt solution that remains after the reaction. The solid-liquid separation can be carried out using vacuum filtration, frame pressure filtration, or centrifugation.

(44) Washing

(45) In step 170, the precipitate may be washed. In some embodiments, the washing process may reduce the salt content from the precipitate. A washing process may remove salts that can act as catalyst poisons and degrade the efficiency of the catalyst. The total alkali in the final product should be less than 3%. In general, an amount of 10 to 30 times the volume of the slurry of deionized water should be used in washing in order to get a product with a total alkali count below 3%.

(46) Drying

(47) In step 180, the washed precipitate may be dried. The drying process can be carried out in an oven flash dryer or spray dryer. The drying temperature may be between 105° C. and 200° C. for about 1 to 4 hours.

(48) In optional step 185, a surface modifying agent that will react with the dried precipitate to preserve structure, diameter, and surface area of the pores of the precipitate during the later calcination step may be added. In some embodiments, step 185 may be performed on the washed precipitate prior to drying step 180. Surface modifying agents may include organic compounds that react rapidly during calcination of the dried precipitate. The surface modifying agent may include one or more of: short chain organic acids, polyols, sugars, polyvinyl alcohol, polyethylene glycol-200, simple alcohols, and organic surfactants. When calcined, the surface modifying agent may modify the crystal structure and materials morphology and pore structure of the dried precipitate to enhance its activity. Optional step 185 is not performed if a surface modifying agent has already been introduced in step 135.

(49) Calcination:

(50) In step 190, the dried precipitate may be calcined. A muffle furnace, tube furnace or tunnel furnace may be used to calcine the dried precipitate. The calcination temperature may be between 250° C. and 800° C. The temperature and time may be determined by the specific formulation. The calcination temperature may be reached using a temperature ramp of between 1 and 50° C./minute to a final temperature between 450° C. and 800° C. The atmosphere within the calcinator may be oxidizing (air), reducing (H.sub.2, CO in nitrogen), or inert (nitrogen).

(51) After calcination, the composition adhering to the formula A.sub.aB.sub.bMn.sub.yO.sub.x can be verified through chemical testing. More specifically, the final composition may be A.sub.0.05-0.25B.sub.0.05-0.25Mn.sub.0.50-0.90O.sub.x where A is the first promoter, B is the second promoter and x is the value of oxygen required to balance the valences of the formula. In some embodiments, A and B are the same element and the formula may be expressed as A.sub.0.10-0.50Mn.sub.0.50-0.90O.sub.x.

(52) In one exemplary and non-limiting embodiment, the method 100 may be performed in the following manner. A first solution of cerium nitrate and zirconium nitrate may be dissolved in water with a manganese salt. Nitric acid may be added to completely dissolve the salts. Then a second solution containing potassium permanganate may be added to the solution. The second solution may also include sodium carbonate. The ratio of salts in the first solution to the potassium permanganate in the second solution may be about 1.25.

(53) The combination of the first solution and second solution form a slurry. The combination process may include slow stirring or agitation controlled to reduce foaming and ensure complete mixing. The amount of sodium carbonate in the second solution may be adjusted to control the pH of the slurry. In this example, the target pH for the slurry is in a range of 7.5 to 10.0. Additional nitric acid or sodium carbonate may be added to the slurry to secure the desired pH value. Then the slurry may be heated and stirred at about 52° C. for about 3 hours. Excess soluble salts may be filtered out and the remaining slurry heated and aged at about 52° C. for about 1 hour. After aging, the precipitate may be separated from the slurry, and then the precipitate may be washed, dried, and finally calcined for about 2 hours at 250° C. to form the final composition.

(54) FIG. 2 shows a method 200 of manufacturing an embodiment of a hybridized MnOX composition according to the present disclosure. In step 210, a solution including a manganese salt, the first promoter and the optional second promoter may be prepared. In some embodiments, an acid, such as nitric acid, may be added to place the manganese salt, the first promoter, and the optional second promoter into solution.

(55) In this case, chlorides, sulfates, hydroxides, oxides, carbonates or nitrates of the following elements: aluminum (Al), barium (Ba), cerium (Ce), lanthanum (La), copper (Cu), iron (Fe), magnesium (Mg), titanium (Ti), yttrium (Y), zirconium (Zr), and zinc (Zn) may be used as starting materials. The solution is comprised of a manganese salt is mixed with two promoter salts in the required molar ratios in water. The amount of water used may be adjusted to have an intermediate solids content of 3.5 to 5.5% by mass in slurry as calculated as oxides. Mineral acids may be added to aid in the dissolution of the reactant salts, such as nitric acid, sulfuric acid, hydrochloric acid and other suitable inorganic acids known to persons of skill in the art. The solution is continuously mixed to ensure complete dispersion of the reactants. The temperature of Solution A will be maintained between 20° C. to 80° C. prior to the synthesis of the intermediate product.

(56) In step 220, an oxidizer, such as a manganate salt, permanganate salt, or hydrogen peroxide is added to the solution in the appropriate ratio to attain the desired final oxidation state of the products, over a period of 30 minutes to three hours to form a slurry.

(57) In step 230, the product may be separated and washed. In step 235, a third promoter may be added and undergo ion exchange to form the intermediate product. The third promoter is the same as at least one of the first promoter and the second promoter.

(58) In optional step 240, a surface modifying agent that will react with the precipitated material to preserve structure, diameter, and surface area of the pores of the precipitate during the later heating or aging steps may be added to the solution. Surface modifying agents may include organic compounds that react rapidly during heating or aging of the precipitate. The surface modifying agent may include one or more of: short chain organic acids, polyols, sugars, polyvinyl alcohol, polyethylene glycol-200, simple alcohols, and organic surfactants. When heated or aged, the surface modifying agent may modify the crystal structure and materials morphology and pore structure of the precipitate in solution to enhance its activity.

(59) In step 245, the slurry may be mixed and/or heated to improve uniformity of the intermediate product. The temperature during the synthesis step may be increased to between 40° C. and 80° C. for subsequent aging. A static mixer and a tank reactor are used at the same time to produce a mixed metal oxide via a redox precipitation method. The use of a Continuous Stirred Tank Reactor (CSTR) allows for a more complete and uniform reaction.

(60) Aging

(61) In step 250, the slurry may be aged. It is common to retain the solids slurry at the precipitation temperature and pH for a period of ranging from about 10 minutes to about 6 hours depending on the composition of the solution. During aging, one or more organic surfactants, such as polyvinyl alcohol (PVA) polyvinyl amine, polyethylene glycol-200 (PEG 200), triton X-100, isopropyl alcohol and ethanol can be used for enlarging pore structure. The dosage is 0.1% to 10%. In some embodiments the dosage is 1% to 5%. In some embodiments, step 250 may take place before step 230.

(62) Separation of Solid-Liquid

(63) In step 260, a precipitate may be separated from the solution after aging. The precipitate in the slurry should be separated from the salt solution that remains after the reaction. The solid-liquid separation can be carried out using vacuum filtration, frame pressure filtration or centrifugation.

(64) Washing

(65) In step 270, the precipitate may be washed. In some embodiments, the washing process may reduce the salt content from the precipitate. A washing process may remove salts that can act as catalyst poisons and degrade the efficiency of the catalyst. The total alkali in the final product should be less than 3%. In general an amount of 10 to 30 times of deionized water should be used in washing in order to get a product with a total alkali count below 1%.

(66) Drying

(67) In step 280, the washed precipitate may be dried. The drying process can be carried out in an oven, flash dryer or spray dryer. The drying temperature may be between 105° C. and 200° C. for about 1 to 4 hours.

(68) Optional step 285 adds a surface modifying agent that will react with the dried precipitate to preserve structure, diameter, and surface area of the pores of the precipitate during the subsequent calcination step. Surface modifying agents may include organic compounds that react rapidly during calcination of the dried precipitate. The surface modifying agent may include one or more of: short chain organic acids, polyols, sugars, polyvinyl alcohol, polyethylene glycol-200, simple alcohols and organic surfactants. When calcined, the surface modifying agent may modify the crystal structure and materials morphology and pore structure of the dried precipitate to enhance its activity. Optional step 285 is not performed if a surface modifying agent has already been introduced in step 240.

(69) Calcination:

(70) In step 290, the dried precipitate may be calcined. A muffle furnace, tube furnace or tunnel furnace may be used to calcine the dried precipitate. The calcination temperature may be between 250° C. and 800° C. The temperature and time may be determined by the specific formulation. The atmosphere within the calcinator may be oxidizing (air), reducing (H.sub.2, CO in Nitrogen), or inert (Nitrogen).

(71) After calcination, the composition adhering to the formula A.sub.aB.sub.bMn.sub.yO.sub.x can be verified through chemical testing. More specifically, the final composition may be A.sub.0.05-0.25B.sub.0.05-0.25Mn.sub.0.50-0.90O.sub.x where A is the first promoter, B is the second promoter and x is the value of oxygen required to balance the valences of the formula. In some embodiments, A and B are the same element and the formula may be expressed as A.sub.0.10-0.50Mn.sub.0.50-0.90O.sub.x.

(72) Thermal Method

(73) FIG. 3 shows a flow chart of another method 300 for manufacturing an embodiment of a hybridized MnOX composition according to the present disclosure. In step 310, a solution including the first promoter, the second promoter, and a lower valence (+2 or +3) manganese salt may be prepared. In some embodiments, the solution may include an acid, such as nitric acid, to place the first promoter, the second promoter, and the manganese salt into solution.

(74) In this case, oxides, hydroxides, carbonates or nitrates of the following elements: aluminum (Al), barium (Ba), cerium (Ce), lanthanum (La), copper (Cu), iron (Fe), magnesium (Mg), titanium (Ti), yttrium (Y), zirconium (Zr), and zinc (Zn) are used as starting materials. A manganese nitrate, or carbonate may be added with a magnesium, aluminum, titanium or barium oxide or nitrate in the required molar ratio.

(75) In step 320, the mixture may be heated to 400-500° C. for a period of about four hours. The mixture is periodically mixed to ensure complete dispersion of the reactants. In step 330, the mixture may be cooled to below 50° C. In step 340, a surface modifying agent may be added to the mixture. In step 350, the mixture may be milled. In some embodiments, some or all of the steps 330-350 are optional. In some embodiments, steps 330-350 may be performed out of order. In step 360, the mixture may be heated at an increased temperature of 950-1050° C. at a rate of between 1 and 50° C./minute and held for 4 to 12 hours to form a mixed oxide catalyst. The atmosphere can either be oxidizing, inert or reducing depending upon the specific formulation.

(76) In step 370, the mixed oxide catalyst is cooled under a dry inert atmosphere to a temperature below 50° C. and either packaged as the final catalyst or used as a support for the deposition of additional catalyst or co-catalyst.

(77) After calcination, the composition adhering to the formula A.sub.aB.sub.bMn.sub.yO.sub.x can be verified through chemical testing. More specifically, the final composition may be A.sub.0.05-0.25B.sub.0.05-0.25Mn.sub.0.50-0.90O.sub.x where A is the first promoter, B is the second promoter and x is the value of oxygen required to balance the valences of the formula. In some embodiments, A and B are the same element and the formula may be expressed as A.sub.0.10-0.50Mn.sub.0.50-0.90O.sub.x.

(78) When used as a support, the previously formed mixed oxide base is mixed with a nitrate, a carbonate or an oxide of cerium, lanthanum, zirconium, or yttrium reacted at 450° C. for four hours and calcined at 950-1100° C. at a rate of between 1 and 50° C./minute and held for 4 to 8 hours.

(79) The product is then cooled under a dry inert atmosphere and used as the NOx oxidation catalyst. Some exemplary, non-limiting compositions include Ce.sub.0.2Mn.sub.0.8O.sub.x, Mg.sub.0.2Mn.sub.0.8O.sub.x, and Al.sub.0.2Mn.sub.0.8O.sub.x.

(80) Embodiments of the present disclosure may be used in catalytic systems comprising at least one of the compositions described above prepared by one of the methods above. The effectiveness of the embodiments may be affected by the way a particular embodiment is used in the exhaust process of a specific internal combustion system.

(81) These catalytic systems, and more particularly these compositions, can have several applications. In some embodiments, the composition may be used as a wash coat within an exhaust system. The wash coat generally is coated onto a base, often made of ceramic or metal, and a noble metal is deposited on the wash coat. This coating may be obtained by mixing the composition with a support to form a suspension that can subsequently be deposited on a substrate. The wash coat may be used as a diesel oxidation catalyst (DOC), a diesel particulate filter (DPF), or a selective catalytic reduction (SCR) catalyst.

(82) Some compositions are suited for and usable in the catalysis of various reactions, such as, but not limited to, dehydration, hydrosulfurization, hydrodenitrification, desulfurization, hydrodesulfurization, dehydrohalogenation, reforming, steam reforming, cracking, hydrocracking, hydrogenation, dehydrogenation, isomerization, dismutation, oxychlorination, dehydrocyclization of hydrocarbons or other organic compounds, oxidation and/or reduction reactions, the Claus reaction, treatment of exhaust gases from internal combustion engines, demetallation, methanation, the shift conversion, oxidation of CO, purification of air by low temperature oxidation (<200° C., indeed even <100° C.), and catalytic oxidation of the soot emitted by internal combustion engines, such as diesel engines or petrol engines operating under lean burn conditions.

(83) Some of the embodiments, such as, Al.sub.0.1Ce.sub.0.2Mn.sub.0.7O.sub.x, may be used in the purification of air, said air notably comprising carbon monoxide, ethylene, aldehyde, amine, mercaptan, ozone, volatile organic compounds, atmospheric pollutants, fatty acids, hydrocarbons, aromatic hydrocarbons, nitrogen oxides or malodorous compounds, comprising the step of bringing into contact gases with a catalytic system containing one or more of the above described compositions.

(84) The following examples are included to illustrate performance embodiments of the invention and are non-limiting. Some embodiments include Al.sub.0.1Ce.sub.0.2Mn.sub.0.7O.sub.x and Zr.sub.0.25Al.sub.0.25Mn.sub.0.5O.sub.x.

(85) While embodiments in the present disclosure have been described in some detail, according to the preferred embodiments illustrated above, it is not meant to be limiting to modifications such as would be obvious to those skilled in the art.

(86) The foregoing disclosure and description of the disclosure are illustrative and explanatory thereof, and various changes in the details of the illustrated apparatus and system, and the construction and the method of operation may be made without departing from the spirit of the disclosure.