Ozone decomposition catalyst, method for preparing the same, and use thereof

Abstract

The application discloses an ozone decomposition catalyst with catalytic performance and water resistance, and a preparation method and application thereof, and belongs to the field of gas purification and treatment in the field of energy and environment. The ozone decomposition catalyst comprises a carrier, an active component, a catalytic component and a reinforcing component; the active component and the catalytic component are loaded on the carrier to form a core layer; and the reinforcing component is wrapped around the periphery of the core layer to form a reinforcing layer. The ozone decomposition catalyst adopts a configuration of "reinforcing layer @ catalytic component" or "reinforcing layer @ catalytic component @ metal honeycomb substrate", so as to ensure the ozone catalytic decomposition performance and water resistance of the catalyst under high flux and high humidity conditions. The metal wall ozone decomposition catalyst with the configuration of "reinforcing layer @ catalytic component @ metal honeycomb substrate" is especially suitable for the ozone decomposition catalyst required in an ozone converter of an aircraft cabin control system and a fuel tank inerting system.

Description

Technical Field

[0001] The present invention belongs to the technical field of gas purification and treatment in the field of energy and environment, and in particular relates to a catalyst suitable for ozone decomposition and removal applications under high humidity and high flux conditions and a preparation method thereof. Background Art

[0002] Ozone in the atmosphere primarily exists in the stratosphere, 5 to 25 km above the ground. Civil aircraft typically fly at altitudes between 7 and 12.5 km, where ozone concentrations range from approximately 0.4 to 0.8 ppm. It's important to note that the aircraft's environmental control system introduces fresh air through the compressor, half of which is then recycled internally. Therefore, at certain cruising altitudes, ozone concentrations inside the aircraft can rise to around 1 to 2 ppm, posing a serious health risk to crew and passengers. Therefore, ozone converters within the environmental control system play a crucial role.

[0003] The core of an ozone converter is the ozone decomposition catalyst installed within it. This catalyst is supported by a monolithic metal honeycomb wall, which decomposes and removes ozone. Due to the unique operating environment characterized by high gas flux and high humidity, ozone converters place stringent demands on the catalyst within them. In addition to ensuring excellent ozone decomposition performance, the ozone decomposition catalyst supported on the metal substrate must also possess excellent mechanical stability and robustness. Conventional ozone decomposition catalysts are typically calcined at relatively low temperatures, below 350°C, to ensure optimal ozone decomposition performance. However, the calcination temperature for a firmly supported catalyst on a metal substrate is typically above 500°C. Such high temperatures can damage the performance of conventional ozone decomposition catalysts. Furthermore, a technical challenge in decomposing and removing ozone in high-humidity air is the catalyst's excellent water resistance. Water forms a film on the catalyst surface, inhibiting ozone adsorption at the active sites and hindering ozone decomposition and removal. Summary of the Invention

[0004] In light of this, the present invention addresses the performance requirements of ozone decomposition catalysts within aircraft ozone converters by providing an ozone decomposition catalyst with a "reinforcement layer @ catalytic component" configuration. This catalyst exhibits excellent ozone decomposition performance and water resistance at high flux, and can be securely supported on a metal honeycomb substrate in a wall-mounted manner, resulting in a monolithic catalyst with a "reinforcement layer @ catalytic component @ metal honeycomb substrate" configuration. By optimizing the preparation process, the issue of catalyst coating firmness on the metal substrate surface has been resolved.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] An ozone decomposition catalyst, comprising a carrier, an active component, a co-catalytic component and a strengthening component;

[0007] The active component and the co-catalytic component are loaded on the carrier to form a core layer;

[0008] The strengthening component is wrapped around the periphery of the core layer to form a strengthening layer;

[0009] The active elements in the active component include Pd and Ni;

[0010] The promoter elements in the promoter component are selected from at least two of Al, Si, La, Ni or Mn;

[0011] The strengthening elements in the strengthening component include Pd and Si.

[0012] Optionally, the total loading amount of the active component and the co-catalytic component is 5% to 50% of the carrier mass; the mass ratio of the active component to the co-catalytic component is 1:2 to 1:10000;

[0013] The thickness of the strengthening layer is 1 to 10 microns.

[0014] A method for preparing the above-mentioned ozone decomposition catalyst comprises the following steps:

[0015] Step 1: Obtain a carrier loaded with active ingredients, and obtain powder A after drying and calcining;

[0016] Step 2: Prepare a mixed solution containing powder A and a co-catalyst component, and ball mill to obtain a slurry S;

[0017] Step 3: After the slurry S is dried, dispersed, roasted and formed, a semi-finished product B is obtained;

[0018] Step 4: Prepare silica sol containing Pd element to obtain strengthening layer precursor P;

[0019] Step 5: The strengthening layer precursor P is loaded onto the semi-finished product B by a spraying method or an impregnation method, and after drying, the ozone decomposition catalyst is obtained.

[0020] Optionally, in step 1, the drying temperature is 50-150° C., and the drying time is 1-24 hours; the calcination conditions are: heating to 450-600° C. at a heating rate of 1-5° C. / min, and maintaining the constant temperature for 1-6 hours;

[0021] In step 2, the mass ratio of the powder A to the catalyst promoter is 1:1 to 10000:1; the solid content of the slurry S is 10 wt% to 50 wt%, and the solid particle size d 50 is 0.5 to 10 μm, and the pH range is 2.0 to 5.0;

[0022] In step 3, the drying temperature is 50-150° C., and the drying time is 1-24 hours. The dispersion is performed by dry mechanical grinding, and the particle size after dispersion is 20-100 μm. The calcination conditions are: heating to 450-600° C. at a heating rate of 1-5° C. / min and maintaining the temperature for 1-6 hours. The particle size of the semi-finished product B is 150-850 μm.

[0023] In step 4, the strengthening layer precursor P exists in the form of a stable sol;

[0024] In step 5, the mass ratio of the strengthening layer precursor P to the semi-finished product B is 1:10 to 1:10000; the drying temperature is 200 to 350° C., and the drying time is 5 to 8 hours.

[0025] The purpose of step 1 is to obtain a carrier loaded with active ingredients in the form of powder.

[0026] Optionally, in step 1, the precursor solution of Pd in ​​the active component may be palladium nitrate, palladium chloride, or a solution obtained by dissolving palladium in aqua regia;

[0027] Preferably, in step 1, the Pd precursor solution is palladium nitrate.

[0028] Optionally, in step 1, the precursor solution of Ni in the active component can be nickel nitrate, nickel sulfate, nickel chloride, nickel hydroxyl, etc.;

[0029] Preferably, in step 1, the Ni precursor solution is nickel nitrate.

[0030] Optionally, the carrier is selected from alumina; the crystal structure of alumina includes α-Al2O3, β-Al2O3, γ-Al2O3, δ-Al2O3, etc.

[0031] Preferably, in step 1, the crystal structure of the alumina powder is mainly γ-Al2O3.

[0032] Optionally, in step 1, the lower limit of the drying temperature is independently selected from 50°C, 60°C, 70°C, 80°C, and 90°C; the upper limit of the drying temperature is independently selected from 80°C, 100°C, 120°C, 130°C, and 150°C.

[0033] Optionally, in step 1, the lower limit of the drying time is independently selected from 1 hour, 2 hours, 3 hours, 5 hours, 7 hours, 10 hours, and 12 hours; the upper limit of the drying time is independently selected from 12 hours, 15 hours, 16 hours, 20 hours, 22 hours, and 24 hours.

[0034] Optionally, in step 1, the lower limit of the calcination temperature is independently selected from 450°C, 500°C, and 550°C; the upper limit of the calcination temperature is independently selected from 500°C, 550°C, and 600°C.

[0035] Optionally, in step 1, the heating rate of the calcination process is selected from 1°C / min, 2°C / min, 3°C / min, 4°C / min or 5°C / min, or any value between any two of the above points.

[0036] Optionally, in step 1, the lower limit of the calcination time is independently selected from 1 hour, 2 hours, and 3 hours; the upper limit of the calcination time is independently selected from 3 hours, 4 hours, 5 hours, and 6 hours.

[0037] The purpose of step 2 is to obtain a slurry containing multiple active substances and having a particle size within a specific range.

[0038] Optionally, in step 2, the lower limit of the solid content of the slurry S is independently selected from 10wt%, 15wt%, 20wt%, 25wt%, and 30wt%; the upper limit of the solid content of the slurry S is independently selected from 30wt%, 40wt%, 45wt%, and 50wt%.

[0039] Optionally, in step 2, the solid phase particle size d of the slurry S is 50 The lower limit of is independently selected from 0.5 μm, 1 μm, 1.5 μm, 2 μm, 3 μm; the solid phase particle size d of the slurry S is 50 The upper limit of is independently selected from 3 μm, 5 μm, 6 μm, 8 μm, and 10 μm.

[0040] Optionally, in step 2, the lower limit of the pH value of the slurry S is independently selected from 2.0, 2.5, and 3.0; the upper limit of the pH value is independently selected from 3.0, 4.0, 4.5, and 5.0.

[0041] The purpose of step 3 is to obtain a semi-finished catalyst with a particle size within a specific range.

[0042] Optionally, in step 3, the lower limit of the drying temperature is independently selected from 50°C, 60°C, 70°C, and 80°C; the upper limit of the drying temperature is independently selected from 80°C, 100°C, 120°C, and 150°C.

[0043] Optionally, in step 3, the lower limit of the drying time is independently selected from 1 hour, 2 hours, 3 hours, 5 hours, 7 hours, 10 hours, and 12 hours; the upper limit of the drying time is independently selected from 12 hours, 15 hours, 16 hours, 20 hours, 22 hours, and 24 hours.

[0044] Optionally, in step 3, the dispersion process adopts a dry mechanical grinding method. After dispersion, the lower limit of the particle size range of the obtained powder is independently selected from 20μm, 30μm, 40μm, and 50μm; the upper limit of the particle size range of the powder is independently selected from 50μm, 60μm, 80μm, 90μm, and 100μm.

[0045] Optionally, in step 3, the lower limit of the calcination temperature is independently selected from 450°C, 500°C, and 550°C; the upper limit of the calcination temperature is independently selected from 500°C, 550°C, and 600°C.

[0046] Optionally, in step 3, the heating rate of the calcination process is selected from 1°C / min, 2°C / min, 3°C / min, 4°C / min or 5°C / min, or any value between the above two points.

[0047] Optionally, in step 3, the lower limit of the calcination time is independently selected from 1 hour, 2 hours, and 3 hours; the upper limit of the calcination time is independently selected from 3 hours, 4 hours, 5 hours, and 6 hours.

[0048] Optionally, in step 3, the molding process includes tableting and crushing of the powder.

[0049] Optionally, in step 3, after forming, the granular semi-finished catalyst B is obtained, and the lower limit of the particle size range is independently selected from 150μm, 175μm, 200μm, 220μm, 250μm, 300μm, and 400μm; the upper limit of the particle size range is independently selected from 400μm, 500μm, 550μm, 600μm, 650μm, 750μm, and 850μm.

[0050] The purpose of step 4 is to prepare a stable silica sol containing a trace amount of Pd, thereby obtaining the precursor sol for the strengthening layer. Since the addition of the Pd elemental solution introduces an electrolyte into the silica sol, which destabilizes the sol, a surfactant is required to adjust the sol's stability.

[0051] Optionally, in step 4, the surfactant is a non-ionic surfactant, including at least one of polyol compounds, polyether compounds, polyester compounds, and polyether-modified silicone compounds.

[0052] The purpose of step 5 is to bond a strengthening layer to the surface of the catalyst component to improve the water resistance of the catalyst without damaging the catalytic performance of the catalyst.

[0053] Optionally, in step 5, the lower limit of the drying temperature is independently selected from 200°C, 230°C, and 250°C; the upper limit of the drying temperature is independently selected from 250°C, 300°C, 330°C, and 350°C; the lower limit of the drying time is selected from 5.5h, 6h, and 6.5h; and the upper limit of the drying time is selected from 7.5h, 7h, and 6.5h.

[0054] The present invention also provides an ozone decomposition catalyst, comprising a carrier, an active component, a co-catalytic component, a strengthening component and a metal matrix; the metal matrix has regular straight pores;

[0055] The surface of the metal substrate is coated with an active layer comprising active components and co-catalytic components; the surface of the active layer is coated with a strengthening layer comprising strengthening components; the coating can be attached to the pore walls of the metal substrate;

[0056] The active component and the co-catalytic component are loaded on the carrier;

[0057] The active elements in the active component include Pd and Ni;

[0058] The promoter elements in the promoter component are selected from at least two of Al, Si, La, Ni or Mn;

[0059] The strengthening elements in the strengthening component include Pd and Si.

[0060] Optionally, the thickness of the active layer is 5 to 100 microns; the thickness of the strengthening layer is 1 to 10 microns;

[0061] The metal substrate is a metal honeycomb substrate; the material of the metal honeycomb substrate is selected from stainless steel or aluminum alloy; the pore density of the metal substrate is 200-800 cpsi; the metal substrate is cylindrical in shape, with a diameter of 10-300 mm and a height of 10-500 mm.

[0062] Optionally, the total loading amount of the active component and the co-catalytic component is 5% to 60% of the mass of the metal matrix; the mass ratio of the active component to the co-catalytic component is 1:2 to 1:10000.

[0063] A method for preparing the above-mentioned ozone decomposition catalyst comprises the following steps:

[0064] Step a: obtaining a carrier loaded with active components, drying and calcining the carrier to obtain carrier A;

[0065] Step b: preparing a mixed solution containing powder A and a co-catalytic component, and ball milling to obtain a slurry S;

[0066] Step c: obtaining a pretreated metal substrate;

[0067] Step d: coating the slurry S on the surface of the pretreated metal substrate, drying and calcining to obtain a semi-finished product D;

[0068] Step e: preparing a silica sol containing Pd element to obtain a strengthening layer precursor P;

[0069] Step f: coating the strengthening layer precursor P onto the surface of the semi-finished product D, and drying the semi-finished product D to obtain the ozone decomposition catalyst.

[0070] Optionally, in step a, the drying temperature is 50-150° C., and the drying time is 1-24 hours; the calcination conditions are: heating to 450-600° C. at a heating rate of 1-5° C. / min, and maintaining the constant temperature for 1-6 hours;

[0071] In step b, the mass ratio of the powder A to the active component is 1:1 to 10000:1; the solid content of the slurry S is 10wt% to 50wt%, and the solid particle size d 50 is 0.5 to 10 μm, and the pH range is 2.0 to 5.0;

[0072] In step d, the viscosity of the slurry S is adjusted to 10 to 300 mPa·s before coating; the drying temperature is 50 to 150°C and the drying time is 1 to 24 hours; the calcination conditions are: heating to 450 to 600°C at a heating rate of 1 to 5°C / min and maintaining the temperature for 1 to 6 hours; the coating loading of the semi-finished product D accounts for 5% to 60% of the mass of the pretreated metal substrate;

[0073] In step e, the strengthening layer precursor P exists in the form of a stable sol;

[0074] In step f, the loading amount of the strengthening layer precursor P accounts for 0.01% to 10% of the semi-finished product D; the drying conditions are: drying at 80 to 120° C. for 0.2 to 2 hours, heating to 200 to 350° C., and continuing for 5 to 8 hours.

[0075] Optionally, the step of obtaining the pretreated substrate comprises: placing the metal substrate in anhydrous ethanol and ultrasonically cleaning it twice, each time for 15 to 25 minutes, taking it out and drying it, and then calcining it at 900 to 1050° C. in an air atmosphere for 2 to 36 hours;

[0076] The metal substrate is made of stainless steel or aluminum alloy, preferably FeCrAl; the metal substrate has regular straight channels with a channel density of 200 to 800 cpsi; the metal substrate is cylindrical in shape with a diameter of 10 to 300 mm and a height of 10 to 500 mm.

[0077] The purpose of step a is to obtain an alumina support loaded with active components in the form of powder.

[0078] Optionally, in step a, the precursor solution of Pd in ​​the active component may be palladium nitrate, palladium chloride, or a solution obtained by dissolving palladium element in aqua regia; preferably, in step 1, the precursor solution of Pd is palladium nitrate.

[0079] Optionally, in step a, the Ni precursor solution in the active component may be nickel nitrate, nickel sulfate, nickel chloride, nickel hydroxyl, etc.; preferably, in step 1, the Ni precursor solution is nickel nitrate.

[0080] Optionally, in step a, the carrier is selected from alumina; the crystal structure of alumina includes α-Al2O3, β-Al2O3, γ-Al2O3, δ-Al2O3, etc.; preferably, in step 1, the crystal structure of alumina powder is mainly γ-Al2O3.

[0081] Optionally, in step a, the lower limit of the drying temperature is independently selected from 50°C, 60°C, 70°C, and 80°C; the upper limit of the drying temperature is independently selected from 80°C, 100°C, 120°C, and 150°C.

[0082] Optionally, in step a, the lower limit of the drying time is independently selected from 1 hour, 2 hours, 3 hours, 5 hours, 8 hours, and 10 hours; the upper limit of the drying time is independently selected from 10 hours, 12 hours, 14 hours, 16 hours, 20 hours, and 24 hours.

[0083] Optionally, in step a, the lower limit of the calcination temperature is independently selected from 450°C, 500°C, and 550°C; the upper limit of the calcination temperature is independently selected from 500°C, 550°C, and 600°C.

[0084] Optionally, in step a, the heating rate of the calcination process is independently selected from 1°C / min, 2°C / min, 3°C / min, 4°C / min or 5°C / min, or any value between any two of the above points.

[0085] Optionally, in step a, the lower limit of the calcination time is independently selected from 1 hour, 2 hours, and 3 hours; the upper limit of the calcination time is independently selected from 3 hours, 4 hours, 5 hours, and 6 hours.

[0086] The purpose of step b is to obtain a slurry containing multiple active substances and having a particle size within a specific range.

[0087] Optionally, in step b, the lower limit of the solid content of the slurry S is independently selected from 10wt%, 15wt%, 20wt%, 25wt%, and 30wt%; the upper limit of the solid content of the slurry S is independently selected from 30wt%, 35wt%, 40wt%, 45wt%, and 50wt%.

[0088] Optionally, in step b, the solid phase particle size d of the slurry S is50 The lower limit of is independently selected from 0.5 μm, 1 μm, 1.5 μm, 2 μm, 2.5 μm, 3 μm; the solid phase particle size d of the slurry S is 50 The upper limit of is independently selected from 3 μm, 4 μm, 5 μm, 6 μm, 8 μm, and 10 μm.

[0089] Optionally, in step b, the lower limit of the pH value of the slurry S is independently selected from 2.0, 2.5, and 3.0; the upper limit of the pH value is independently selected from 3.0, 4.0, 4.5, and 5.0.

[0090] In the step c, the metal substrate has regular straight channels.

[0091] Optionally, the material of the metal matrix can be various types of stainless steel, or FeCrAl alloy; preferably, the metal matrix is ​​made of FeCrAl alloy with regular pores.

[0092] The purpose of step d is to firmly load the slurry S obtained in step 2 onto the pretreated metal substrate provided in step 3 to obtain a wall-supported catalyst coating of the ozone decomposition catalyst semi-finished product D.

[0093] The viscosity of the slurry S is adjusted to be in the range of 10 to 300 mPa·s.

[0094] Optionally, the lower limit of the viscosity of the slurry S is independently selected from 10mPa·s, 20mPa·s, 30mPa·s, 40mPa·s, 50mPa·s, and 60mPa·s; the upper limit of the viscosity of the slurry S is independently selected from 50mPa·s, 100mPa·s, 150mPa·s, 200mPa·s, 250mPa·s, and 300mPa·s.

[0095] The coating loading of the wall-supported catalyst sample D accounts for 5% to 60% of the mass of the metal substrate.

[0096] Optionally, the lower limit of the wall-borne coating's mass to the metal substrate is independently selected from 5%, 10%, 15%, and 20%; the upper limit of the wall-borne coating's mass to the metal substrate is independently selected from 20%, 25%, 30%, 35%, 40%, 50%, and 55%.

[0097] The slurry S can be applied once or multiple times, and the specific number of coatings is determined by the actual demand for coating load.

[0098] Optionally, in step d, the lower limit of the drying temperature is independently selected from 50°C, 60°C, 70°C, and 80°C; the upper limit of the drying temperature is independently selected from 80°C, 100°C, 120°C, and 150°C.

[0099] Optionally, in step d, the lower limit of the drying time is independently selected from 1 hour, 2 hours, 3 hours, 5 hours, 7 hours, and 10 hours; the upper limit of the drying time is independently selected from 10 hours, 12 hours, 14 hours, 16 hours, 20 hours, and 24 hours.

[0100] Optionally, in step d, the lower limit of the calcination temperature is independently selected from 450°C, 500°C, and 550°C; the upper limit of the calcination temperature is independently selected from 500°C, 550°C, and 600°C.

[0101] Optionally, in step d, the heating rate of the calcination process is independently selected from 1°C / min, 2°C / min, 3°C / min, 4°C / min or 5°C / min, or any value between the above two points.

[0102] Optionally, in step d, the lower limit of the calcination time is independently selected from 1 hour, 2 hours, and 3 hours; the upper limit of the calcination time is independently selected from 3 hours, 4 hours, 5 hours, and 6 hours.

[0103] The purpose of step e is to prepare a stable silica sol containing a trace amount of Pd, thereby obtaining the precursor sol for the strengthening layer. Since the addition of the Pd elemental solution introduces an electrolyte into the silica sol, which destabilizes the sol, a surfactant is required to adjust the sol's stability.

[0104] Optionally, in step e, the surfactant is a non-ionic surfactant, including at least one of polyol compounds, polyether compounds, polyester compounds, and polyether-modified silicone compounds.

[0105] The purpose of step f is to bond a layer of the strengthening layer to the surface of the metal wall-supported catalyst semi-finished product D, so as to improve the water resistance of the catalyst while not damaging the catalytic performance of the catalyst.

[0106] Optionally, in step f, the lower limit of the drying temperature is independently selected from 200°C, 230°C, and 250°C; the upper limit of the drying temperature is independently selected from 250°C, 280°C, 300°C, 330°C, and 350°C.

[0107] Optionally, in step f, the lower limit of the drying time is independently selected from 1 hour, 2 hours, 3 hours, 5 hours, 7 hours, and 10 hours; the upper limit of the drying time is independently selected from 10 hours, 12 hours, 14 hours, 16 hours, 20 hours, and 24 hours.

[0108] In the present application, the preparation method of silica sol containing Pd includes: (1) weighing 75 parts of acidic silica sol with a solid content of 20%, 5 parts of methyl cellulose aqueous solution with a concentration of 2.5%, and 5 parts of dilute nitric acid with a concentration of 3M, placing them in a three-necked flask, and continuously stirring them under water bath heating conditions, maintaining the temperature at 45°C, and marking them as Pa; (2) weighing 14 parts of polyvinyl alcohol aqueous solution with a concentration of 5% and 1 part of palladium nitrate aqueous solution with a concentration of 100 mg / mL, mixing them and stirring them evenly, and marking them as Pb; (3) adding the Pb mixture dropwise to Pa at a rate of 2 mL / min, maintaining the stirring state and controlling the temperature of the mixture at 45°C. After the complete addition is completed, stirring is continued for 30 minutes, and then heating is stopped. Stirring is continued for 1 hour under natural cooling to obtain a stable silica sol containing trace amounts of Pd.

[0109] The present invention also provides the above-mentioned ozone decomposition catalyst, and the use of the ozone decomposition catalyst obtained by the above-mentioned preparation method in ozone decomposition and removal; in particular, the use in ozone decomposition and removal under the conditions of temperature 50-250°C, relative humidity 0%-100%, and gas flux 10-2000g / s.

[0110] The ozone decomposition catalyst of the "reinforcement layer@catalytic component" configuration provided by the present invention is mainly applied in the form of particles.

[0111] The ozone decomposition catalyst of the "reinforcement layer @ catalytic component @ metal honeycomb matrix" configuration provided by the present invention exists in the form of an integral configuration and is suitable for applications in which the gas processing volume is large, and is particularly suitable for applications in ozone converters in environmental control systems and fuel tank inerting systems on aircraft.

[0112] The beneficial effects of the present invention include but are not limited to:

[0113] (1) The ozone decomposition catalyst of the "reinforcement layer@catalytic component" configuration provided by the present invention has the characteristics of good ozone catalytic decomposition performance and good water resistance, is suitable for ozone decomposition needs under high-throughput conditions, and can meet the requirements of the metal wall-supported catalyst preparation process.

[0114] (2) The metal wall-borne ozone decomposition catalyst of the overall configuration of "reinforcement layer @ catalytic component @ metal honeycomb matrix" provided by the present invention has excellent ozone catalytic decomposition performance and water resistance, and the wall-borne coating has excellent firmness, which fully meets the application requirements of the ozone decomposition catalyst inside the ozone converter involved in the airborne environmental control system and the fuel tank inerting system. DETAILED DESCRIPTION

[0115] The present invention is further described in detail below through specific examples, but this should not be understood as limiting the scope of the above claims of the present invention to the following examples.

[0116] Ozone conversion rate % = (1-outlet ozone concentration / inlet ozone concentration) * 100%

[0117] Example 1

[0118] This example describes the preparation process of the ozone decomposition catalyst of the "reinforcement layer@catalytic component" configuration.

[0119] Step 1: Prepare a carrier for loading active components. The specific process is as follows:

[0120] (1) Weigh 38.93 g of Ni(NO3)2·6H2O solid and 10 mL of 100 mg / mL palladium nitrate aqueous solution into a 100 mL volumetric flask. Add an appropriate amount of deionized water to dissolve and adjust the volume to 100 mL. Then transfer the mixed solution into a 500 mL three-necked flask and heat and stir in a water bath at 80°C. (2) Add 100 g of γ-Al2O3 evenly into the three-necked flask at a rate of 10 g / min. After the γ-Al2O3 is completely added, continue stirring for 20 minutes. (3) Take out the γ-Al2O3 loaded with Pd and Ni, place it in an oven and dry it at 120°C for 6 hours. Then, heat it in a muffle furnace at a heating rate of 3°C / min to 500°C and keep it at 500°C for 4 hours. After cooling naturally, take it out for use and mark it as A-1.

[0121] Step 2: Prepare slurry. The specific process is as follows:

[0122] (1) Quantitatively weigh 25 parts of active component-loaded carrier A-1, 5 parts of LaNiO3, 5 parts of NiAl2O4, 5 parts of pseudo-boehmite, 3 parts of nitric acid, 10 parts of polyvinyl alcohol (PVA-1750) aqueous solution (concentration of 2.5%) and 47 parts of deionized water, mix and then use mechanical ball milling for 8 hours to obtain a slurry labeled S-1. The average particle size of the solid phase particles in the slurry was measured using a Malvern particle size analyzer. The average value of the three measurements was taken, d 50 The particle size was 2.415 μm, and the pH of the slurry was measured to be 3.95.

[0123] Step 3: Prepare the semi-finished catalyst. The specific process is as follows:

[0124] (1) Take an appropriate amount of slurry S-1 and place it in an oven to dry at 120°C for 6 hours; (2) Mechanically grind and sieve the dried solid to obtain a powder with an average particle size range of 40 to 80 μm; (3) Place the powder in a muffle furnace, heat it to 500°C at a heating rate of 3°C / min, and keep it at 500°C for 4 hours; (4) Process the calcined powder through a tableting process and a crushing process to obtain an irregular granular catalyst semi-finished product with an average particle size range of 500 to 800 μm, marked as B-1.

[0125] Step 4: Prepare a stable silica sol containing trace amounts of Pd. The specific process is as follows:

[0126] (1) Weigh 75 parts of acidic silica sol with a solid content of 20%, 5 parts of methyl cellulose aqueous solution with a concentration of 2.5%, and 5 parts of dilute nitric acid with a concentration of 3M, put them into a three-necked flask, and continue stirring under water bath heating conditions, maintaining the temperature at 45°C, and mark them as Pa; (2) Weigh 14 parts of polyvinyl alcohol aqueous solution with a concentration of 5% and 1 part of palladium nitrate aqueous solution with a concentration of 100 mg / mL, mix and stir evenly, and mark them as Pb; (3) Add the Pb mixture dropwise to Pa at a rate of 2 mL / min, keep stirring during the period and control the temperature of the mixture at 45°C. After the addition is complete, continue stirring for 30 minutes, then stop heating, and continue stirring for 1 hour under natural cooling conditions to obtain a stable silica sol containing trace amounts of Pd, marked as the precursor P-1 of the strengthening layer.

[0127] Step 5: Load preparation of the strengthening layer. The specific process is as follows:

[0128] (1) Weigh 95 parts of B-1 particles and place them in a tray on a shaker, keeping them in a periodic left-right shaking state; (2) Weigh 5 parts of P-1 solution and spray the P-1 solution evenly onto the B-1 particles through an atomizing nozzle; (3) Place the sample obtained after spraying in an oven and dry it at 250°C for 6 hours to obtain a finished catalyst with a "strengthening layer@catalytic component" configuration. The strengthening layer thickness is 3.7 μm and is marked as Example-1.

[0129] Example 2

[0130] This embodiment describes the preparation process of the ozone decomposition catalyst of the “reinforcement layer @ catalytic component @ metal honeycomb matrix” configuration.

[0131] Step a: Prepare a carrier for loading active components. The specific process is as follows:

[0132] (1) Weigh 38.93g of Ni(NO3)2·6H2O solid and 10mL of 100mg / mL palladium nitrate aqueous solution into a 100mL volumetric flask. Add appropriate amount of deionized water to dissolve and adjust the volume to 100mL. Then transfer the mixed solution into a 500mL three-necked flask and heat and stir in a water bath at 80℃. (2) Add 100g of γ-Al2O3 into the three-necked flask at a rate of 10g / min. After the γ-Al2O3 is completely added, continue stirring for 20min. (3) Take out the γ-Al2O3 loaded with Pd and Ni, put it into an oven and dry it at 120℃ for 6 hours. Then, heat it to 500℃ in a muffle furnace at a heating rate of 3℃ / min and keep it at 500℃ for 4 hours. After cooling naturally, take it out for use and mark it as A-2.

[0133] Step b: preparing slurry, the specific process is as follows:

[0134] (1) Quantitatively weigh 25 parts of active component-loaded carrier A-2, 5 parts of LaNiO3, 5 parts of NiAl2O4, 5 parts of pseudo-boehmite, 3 parts of inorganic acid, 10 parts of polyvinyl alcohol aqueous solution (concentration of 2.5%) and 47 parts of deionized water, mix and then use mechanical ball milling for 8 hours to obtain a slurry labeled S-2. The average particle size of the solid phase particles in the slurry was measured using a Malvern particle size analyzer. The average value of the three measurements was taken, d 50 The particle size was 2.397 μm, and the pH of the slurry was measured to be 3.91.

[0135] Step c: Pretreatment of the metal honeycomb matrix. The specific process is as follows:

[0136] A 600 cpsi FeCrAl metal honeycomb substrate with regular straight pores and a cylindrical shape measuring 15 x 20 mm was selected. The metal substrate was first ultrasonically cleaned twice in anhydrous ethanol for 20 minutes each time. After drying, it was calcined in a muffle furnace at 925°C in air for 16 hours. The resulting metal honeycomb substrate was labeled F-2.

[0137] Step d: Preparation of metal wall-supported catalyst, the specific process is as follows:

[0138] (1) The viscosity of slurry S-2 was adjusted to 55 mPa·s, and the slurry S-2 was evenly coated on the pretreated metal honeycomb substrate F-2. The metal honeycomb substrate F-2 was purged with air to remove excess slurry, and then dried in an oven at 110°C for 2 hours. The obtained sample was marked as F-2-a; (2) Slurry S-2 was coated on F-2-a again, and then dried at 110°C; (3) The dried sample was heated to 500°C in a muffle furnace at a heating rate of 3°C / min, and kept at 500°C for 2 hours to obtain a semi-finished sample of a metal honeycomb ozone decomposition catalyst with a catalyst coating loading of 22.35% and a catalyst coating thickness of 18.9 μm, marked as D-2.

[0139] Step e: Preparation of a stable silica sol containing a trace amount of Pd. The specific process is as follows:

[0140] (1) Weigh 75 parts of acidic silica sol with a solid content of 20%, 5 parts of methyl cellulose aqueous solution with a concentration of 2.5%, and 5 parts of dilute nitric acid with a concentration of 3M, put them into a three-necked flask, and continue stirring under water bath heating conditions, maintaining the temperature at 45°C, and mark them as Pc; (2) Weigh 14 parts of 5% polyvinyl alcohol aqueous solution and 1 part of 100 mg / mL palladium nitrate aqueous solution, mix them and stir them evenly, and mark them as Pd; (3) Add the Pd mixed solution dropwise to Pc at a rate of 2 mL / min, keep stirring during the process and control the temperature of the mixed solution at 45°C. After the addition is complete, continue stirring for 30 minutes, then stop heating, and continue stirring for 1 hour under natural cooling conditions to obtain a stable silica sol containing trace amounts of Pd, marked as the precursor P-2 of the strengthening layer.

[0141] Step f: Preparation of the load of the strengthening layer. The specific process is as follows:

[0142] (1) The precursor P-2 sol was evenly coated on the semi-finished sample D-2, and the excess slurry was blown through D-2 with air; (2) The sample was placed in an oven and dried at 100°C for 1 hour; (3) The oven temperature was increased to 250°C and maintained for 4 hours, with a strengthening layer loading of 4.5%; (4) After natural cooling, a finished catalyst having a "strengthening layer @ catalytic component @ metal honeycomb substrate" configuration was obtained, with a strengthening layer thickness of 4.1 μm, marked as Example-2.

[0143] Comparative Example 1

[0144] This embodiment describes the preparation process of an ozone decomposition catalyst without the "strengthening layer", which is as follows:

[0145] Step 1: Prepare a carrier loaded with active ingredients. The specific process is the same as that described in Step 1 of Example 1. The obtained carrier is labeled as Ac-1.

[0146] Step 2: Prepare slurry. The specific process is the same as that of step 2 in Example 1. The obtained slurry is marked as Sc-1. The average particle size of the solid phase particles in the slurry is measured using a Malvern particle size analyzer. The average value of the three measurements is d 50 The particle size was 2.338 μm, and the pH of the slurry was measured to be 3.86.

[0147] Step 3: Prepare the finished catalyst. The specific process is the same as that described in Step 3 of Example 1, and obtain an irregular granular catalyst product with an average particle size ranging from 500 to 800 μm, which is marked as Comparison-1.

[0148] Comparative Example 2

[0149] This embodiment describes the preparation process of an ozone decomposition catalyst having a "catalytic component@metal honeycomb matrix" configuration without the "reinforcement layer", as follows:

[0150] Step 1: Prepare a carrier loaded with active ingredients. The specific process is the same as that described in Step 1 of Example 2. The obtained carrier is labeled as Ac-2.

[0151] Step 2: Prepare slurry. The specific process is the same as that described in step 2 of Example 2. The obtained slurry is marked as Sc-2. The average particle size of the solid phase particles in the slurry is measured using a Malvern particle size analyzer. The average value of the three measurements is d 50 The particle size was 2.495 μm, and the pH of the slurry was measured to be 3.99.

[0152] Step 3: Pretreatment of the metal honeycomb substrate. The specific process is the same as that described in Step 3 of Example 2. The metal honeycomb substrate after pretreatment is marked as Fc-2.

[0153] Step 4: Preparation of metal wall-supported catalyst. The specific process is the same as that described in Step 4 of Example 2, and a metal honeycomb ozone decomposition catalyst with a catalyst coating loading of 23.9% is obtained, which is marked as Comparison-2.

[0154] Test Case

[0155] The performance of the granular ozone decomposition catalysts prepared by the methods of Example 1 and Comparative Example 1 was compared. An ozone decomposition performance comparison experiment was conducted under the same conditions. The experimental conditions were as follows: gas mass space velocity (WHSV) of 2,000,000 mL / g·h, reaction temperature of 180°C, catalyst inlet ozone concentration of 2 ppm, and water content of 4.2%. The changing trends of the ozone concentration at the outlet of each catalyst were examined. As shown in Table 1, the performance of catalyst Example-1 in Example 1 was significantly better than that of catalyst Comparison-1 in Comparative Example 1.

[0156] Table 1 Comparison of catalyst performance in Example 1 and Comparative Example 1

[0157]

[0158] The performance of the ozone decomposition catalysts prepared by the methods of Example 2 and Comparative Example 2 was compared. An ozone decomposition performance comparison experiment was conducted under the same conditions. The experimental conditions were as follows: a gas volume space velocity (GHSV) of 500,000 mL / g·h, a reaction temperature of 180°C, an ozone concentration of 2 ppm at the catalyst inlet, and a water content of 4.2%. The changing trends of the ozone concentrations at the outlets of the catalysts were examined. As shown in Table 2, the performance of catalyst Example-2 in Example 2 was significantly better than that of catalyst Comparison-2 in Comparative Example 2.

[0159] Table 2 Comparison of catalyst performance in Example 2 and Comparative Example 2

[0160]

[0161] The above descriptions are merely a few embodiments of the present application and do not constitute any form of limitation to the present application. Although the present application discloses the preferred embodiments as above, they are not intended to limit the present application. Any technical personnel familiar with the present profession, without departing from the scope of the technical solution of the present application, using the technical content disclosed above to make slight changes or modifications are equivalent to equivalent implementation cases and fall within the scope of the technical solution.

Claims

1. An ozone decomposition catalyst, characterized in that The ozone decomposition catalyst comprises a carrier, an active component, a co-catalytic component and a strengthening component; The active component and the co-catalytic component are loaded on the carrier to form a core layer; The strengthening component is wrapped around the periphery of the core layer to form a strengthening layer; The active elements in the active component are composed of Pd and Ni; The promoter elements in the promoter component are composed of La and Ni; The strengthening component is a silica sol containing Pd; The thickness of the strengthening layer is 1 to 10 microns.

2. The ozone decomposition catalyst according to claim 1, characterized in that The total loading amount of the active component and the co-catalytic component is 5% to 50% of the carrier mass; the mass ratio of the active component to the co-catalytic component is 1:2 to 1:10000.

3. An ozone decomposition catalyst, characterized in that The ozone decomposition catalyst comprises a carrier, an active component, a catalytic promoter component, a strengthening component and a metal matrix; the metal matrix has regular straight pores; The surface of the metal substrate is coated with an active layer comprising an active component and a catalytic promoter component; the surface of the active layer is coated with a strengthening layer comprising a strengthening component; The active component and the co-catalytic component are loaded on the carrier; The active elements in the active component are composed of Pd and Ni; The promoter elements in the promoter component are composed of La and Ni; The strengthening component is a silica sol containing Pd; The thickness of the active layer is 5 to 100 microns; the thickness of the strengthening layer is 1 to 10 microns.

4. The ozone decomposition catalyst according to claim 3, characterized in that The metal substrate is a metal honeycomb substrate; the material of the metal honeycomb substrate is selected from stainless steel or aluminum alloy; The pore density of the metal matrix is ​​200-800 cpsi; The metal substrate is cylindrical in shape with a diameter of 10-300 mm and a height of 10-500 mm; The total loading amount of the active component and the co-catalytic component is 5% to 60% of the mass of the metal matrix; the mass ratio of the active component to the co-catalytic component is 1:2 to 1:10000.

5. A method for preparing the ozone decomposition catalyst according to claim 1 or 2, characterized in that: The following steps are involved: Step 1: Obtain a carrier loaded with active ingredients, and obtain powder A after drying and calcining; Step 2: Prepare a mixed solution containing powder A and a co-catalyst component, and ball mill to obtain a slurry S; Step 3: After the slurry S is dried, dispersed, roasted and formed, a semi-finished product B is obtained; Step 4: Prepare silica sol containing Pd element to obtain strengthening layer precursor P; Step 5: The strengthening layer precursor P is loaded onto the semi-finished product B by a spraying method or an impregnation method, and after drying, the ozone decomposition catalyst is obtained.

6. A method for preparing the ozone decomposition catalyst according to claim 3 or 4, characterized in that: The following steps are involved: Step a: obtaining a carrier loaded with active components, drying and calcining the carrier to obtain carrier A; Step b: preparing a mixed solution containing powder A and a co-catalytic component, and ball milling to obtain a slurry S; Step c: obtaining a pretreated metal substrate; Step d: coating the slurry S on the surface of the pretreated metal substrate, drying and calcining to obtain a semi-finished product D; Step e: preparing a silica sol containing Pd element to obtain a strengthening layer precursor P; Step f: coating the strengthening layer precursor P onto the surface of the semi-finished product D, and drying the semi-finished product D to obtain the ozone decomposition catalyst.

7. The preparation method according to claim 5 or 6, characterized in that: In step 1 and step a, the drying temperature is independently 50-150° C., and the drying time is independently 1-24 h; The calcination conditions are independently as follows: heating to 450-600°C at a heating rate of 1-5°C / min and maintaining the temperature for 1-6 hours; In step 2 and step b, the mass ratio of the powder A to the catalyst promoter is independently 1:1 to 10000:1; the solid content of the slurry S is independently 10 wt% to 50 wt%, and the solid particle size d is 50 independently 0.5–10 μm, and the pH range independently 2.0–5.0; In step 3 and step d, the drying temperature is independently 50-150°C, and the drying time is independently 1-24 hours; the calcination conditions are independently: heating to 450-600°C at a heating rate of 1-5°C / min, and maintaining the constant temperature for 1-6 hours.

8. The preparation method according to claim 5, characterized in that In step 3, the dispersion is carried out by dry mechanical grinding, and the particle size after dispersion is 20-100 μm; the particle size of the semi-finished product B is 150-850 μm; In step 5, the mass ratio of the strengthening layer precursor P to the semi-finished product B is 1:10 to 1:10000; the drying temperature is 200 to 350 o C, time is 5~8h.

9. The preparation method according to claim 6, characterized in that In step c, the step of obtaining a pretreated metal substrate comprises: ultrasonically cleaning the metal substrate twice in anhydrous ethanol for 15 to 25 minutes each time, taking it out to dry, and then calcining it at 900 to 1050° C. in an air atmosphere for 2 to 36 hours; In step d, the coating loading of the semi-finished product D accounts for 5% to 60% of the mass of the pretreated metal substrate; In step f, the loading amount of the strengthening layer precursor P accounts for 0.01% to 10% of the semi-finished product D; the drying treatment conditions are: drying at 80 to 120°C for 0.2 to 2 hours, heating to 200 to 350°C, and drying at 100 to 200°C. o C, continue for 5~8 hours.

10. Use of the ozone decomposition catalyst according to any one of claims 1 to 4 or the ozone decomposition catalyst prepared by the preparation method according to any one of claims 5 to 9 in ozone decomposition and removal; Application in ozone decomposition and removal under the conditions of temperature 50~250℃, relative humidity 0~100%, and gas flux 10~2000g / s.

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