Monolithic catalytic material and monolithic catalyst, preparation method therefor and use thereof, and catalytic oxidation method

Abstract

A monolithic catalytic material and a monolithic catalyst, a preparation method therefor and use thereof, and a catalytic oxidation method. The monolithic catalytic material comprises a structured support and a modified alumina coating distributed on the structured support. The modified alumina coating comprises an alumina-containing coating and a manganese-cobalt composite oxide supported on the surface of the alumina-containing coating. The monolithic catalytic material has better catalytic activity.

Description

Monolithic catalytic material and monolithic catalyst, preparation method and application thereof, and catalytic oxidation method Technical Field

[0001] The present invention relates to the field of waste gas treatment, and in particular to a monolithic catalytic material and a monolithic catalyst, a preparation method and application thereof, and a catalytic oxidation method. Background Art

[0002] Catalytic oxidation is a common method for treating VOCs in petrochemical exhaust gases. Due to the large gas volumes and high flow rates involved, honeycomb ceramics are generally used as catalyst carriers. The active centers used for catalytic oxidation are generally precious metal active centers. Since precious metal active centers are expensive, people are considering using non-precious metal active centers to replace precious metals. Manganese has multiple oxidation states and can undergo redox reactions between different oxidation states, effectively regulating the oxidation activity of Mn-based catalysts. By regulating the oxidation state and coordination environment of manganese, the catalyst can exhibit good activity. Mn-based catalysts generally have good catalytic stability. Manganese has high resistance to poisoning and sintering in redox reactions, and can maintain good catalytic activity under a variety of exhaust gas components and conditions, thereby extending the service life of the catalyst.

[0003] Mn-based catalytic oxidation catalysts can be prepared by chemical synthesis or direct pyrolysis. This method has the characteristics of simple preparation, but low catalytic activity per unit mass. Mn metal salts can also be loaded on a carrier by impregnation or chemical deposition, and then converted into the corresponding oxide after drying and calcining. The dispersion of the metal particles obtained by this method is improved compared to the non-loaded method, and the preparation process is simple, but the degree of dispersion often decreases with the increase of metal loading. A precursor compound containing Mn can also be doped into a slurry system and then coated on a carrier honeycomb ceramic. Monolithic catalysts are the mainstream of VOC catalytic oxidation catalysts, but the Mn loading in this method is not high.

[0004] Manganese-based monolithic catalysts are typically prepared by adding a small amount of Mn to a conventional slurry formulation, or by loading the slurry coating after it has dried, calcined, and stabilized. The former is affected by the slurry's stability; excessive addition can severely compromise its stability. The latter, simply loading the catalyst, makes it difficult to generate interaction forces with the precious metal center.

[0005] CN111085217A discloses a three-dimensional porous Mn-Co nanosphere grown on cordierite. The microspheres are formed by introducing cobalt into the skeleton of manganese oxide to form a cobalt-manganese spinel composite oxide with a three-dimensional porous structure. The microspheres are mainly formed by agglomerating a large number of small nanoparticles and can be evenly distributed on the pore walls of the honeycomb ceramic cordierite. The synthesis process does not introduce a slurry and is prepared by growing cobalt-manganese oxide directly on the surface of cordierite. However, its loading capacity is limited, and the amount of active centers is severely restricted. At the same time, due to the lack of sufficient microscopic pores and corresponding specific surface area, it does not have the ability to subsequently load precious metals. Its catalytic performance needs to be further improved.

[0006] Summary of the Invention

[0007] In response to the shortcomings of the prior art, the present invention provides a monolithic catalytic material and a monolithic catalyst, as well as a preparation method and application thereof, and a catalytic oxidation method. The monolithic catalyst provided by the present invention has high catalytic oxidation activity when applied to the catalytic oxidation reaction of VOCs.

[0008] The first aspect of the present invention provides an integral catalytic material, comprising a regular structure support and a modified alumina coating distributed on the regular structure support, wherein the modified alumina coating comprises a coating containing alumina and a manganese-cobalt composite oxide supported on the surface of the coating containing alumina.

[0009] Preferably, the manganese-cobalt composite oxide has a morphology of spherical or quasi-spherical particles formed by cross-stacked rod-like structures.

[0010] Preferably, the surface layer of the rod-like structure is MnO2, and the interior is MnCo2O4; further preferably, the thickness of the surface layer of the rod-like structure MnO2 is 1nm to 3nm.

[0011] A second aspect of the present invention provides a method for preparing a monolithic catalytic material, the method comprising the following steps:

[0012] (1) introducing a coating slurry containing aluminum oxide and / or its precursor into a structured support, followed by drying and optionally calcining to obtain a structured support loaded with a coating containing aluminum oxide;

[0013] (2) The structured support carrying the coating layer containing aluminum oxide is reacted with a manganese precursor and a cobalt precursor in the presence of a solvent, and then dried.

[0014] Preferably, the coating slurry contains aluminum oxide and a solvent, and optionally a surfactant, optionally an aluminum oxide precursor, and optionally a silicon source. Further preferably, the coating slurry has a pH of 3 to 4, and / or a viscosity of 10 to 100 mPa·s.

[0015] The third aspect of the present invention provides a monolithic catalyst, which comprises the monolithic catalytic material described in the first aspect or the monolithic catalytic material prepared by the preparation method described in the second aspect, and a precious metal component.

[0016] The fourth aspect of the present invention provides a method for preparing an integral catalyst, which comprises impregnating the integral catalytic material described in the first aspect or the integral catalytic material prepared by the preparation method described in the second aspect in an impregnation solution containing a precious metal precursor, adjusting the pH to alkaline, allowing to stand, and then drying and calcining.

[0017] The fifth aspect of the present invention provides use of the monolithic catalytic material described in the first aspect or the monolithic catalyst described in the third aspect in a catalytic oxidation reaction, preferably in a catalytic oxidation reaction of VOCs.

[0018] The sixth aspect of the present invention provides a method for catalytic oxidation of VOCs, which comprises contacting exhaust gas containing VOCs with the integral catalyst described in the third aspect to carry out a catalytic oxidation reaction.

[0019] The present invention introduces an aluminum oxide coating on the surface of a structured support and loads a manganese-cobalt composite oxide onto the aluminum oxide coating, resulting in a monolithic catalyst with a bimetallic oxide system exhibiting enhanced catalytic activity. In preferred embodiments, the unique morphology and composition of the manganese-cobalt composite oxide further facilitates the subsequent high dispersion of precious metals, thereby enhancing the catalytic activity of the monolithic catalyst. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG1 is a scanning electron microscope photograph of the monolithic catalytic material prepared in Example 1;

[0021] FIG2 is an XRD spectrum of the monolithic catalytic material prepared in Example 1;

[0022] FIG3 is a Raman spectrum of the monolithic catalytic material prepared in Example 1;

[0023] FIG4 is a SEM image of the monolithic catalytic material prepared in Example 1;

[0024] FIG5 is a STEM image of the monolithic catalytic material prepared in Example 1;

[0025] FIG6 is a stability evaluation curve diagram of Example 1. DETAILED DESCRIPTION

[0026] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0027] In the present invention, unless otherwise explicitly stated, percentages and contents are all based on mass.

[0028] The first aspect of the present invention provides an integral catalytic material, comprising a regular structure support and a modified alumina coating distributed on the regular structure support, wherein the modified alumina coating comprises a coating containing alumina and a manganese-cobalt composite oxide supported on the surface of the coating containing alumina.

[0029] In the present invention, the term "monolithic catalytic material" refers to a catalytic material comprising a regular structure support and a modified alumina coating distributed on the regular structure support; the "regular structure support" is a carrier with a regular structure.

[0030] In the present invention, the modified alumina coating layer may be distributed on the inner surface and / or outer surface of the structured support.

[0031] According to a preferred embodiment of the present invention, based on the total amount of the integral catalytic material, the content of the regular structure support is 80-95wt%, preferably 85-92wt%, for example, 85wt%, 86wt%, 87wt%, 88wt%, 89wt%, 90wt%, 91wt% or 92wt%, and the content of the modified alumina coating is 5-20wt%, preferably 8-15wt%, for example, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt% or 15wt%.

[0032] In the present invention, the content of the regular structure support and the content of the modified alumina coating in the integral catalytic material can be tested by conventional technical means in the field, for example, they can be obtained by weighing the weight of the material before and after coating, or by determining its weight based on the shape of the regular structure support and the manufacturer, and then calculating the percentage of the regular structure support.

[0033] According to the present invention, preferably, based on the total amount of the modified alumina coating, the content of the coating containing alumina is 85-95wt%, for example, 85wt%, 86wt%, 87wt%, 88wt%, 89wt%, 90wt%, 91wt%, 92wt%, 93wt%, 94wt% or 95wt%, and the content of manganese-cobalt composite oxide is 5-15wt%, for example, 5wt%, 6wt%, 7wt%, 8wt%, 9wt%, 10wt%, 11wt%, 12wt%, 13wt%, 14wt% or 15wt%.

[0034] In the present invention, the total amount of the modified alumina coating is used as a benchmark. The content of the alumina-containing coating and the manganese-cobalt composite oxide is measured by inductively coupled plasma optical emission spectrometry (ICP) to obtain the metal element content, which is then converted into the oxide content. Specifically, an AVIO 500 inductively coupled plasma optical emission spectrometer (ICP) from PerkinElmer (USA) can be used. Prior to testing, the sample is digested with aqua regia at a solid-to-liquid ratio of 1:3 and heated at 50°C until clear.

[0035] According to a preferred embodiment of the present invention, the manganese-cobalt composite oxide comprises MnCo2O4 and MnO2. Preferably, based on the total amount of the modified alumina coating, the content of some Mn and Co as MnCo2O4 is 4-15 wt%, for example, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, 10 wt%, 11 wt%, 12 wt%, 13 wt%, 14 wt%, or 15 wt%, and the content of the remaining Mn as MnO2 is 0.1-1 wt%, for example, 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, 0.6 wt%, 0.7 wt%, 0.8 wt%, 0.9 wt%, or 1 wt%. The monolithic catalytic material provided by the present invention can achieve high catalytic oxidation performance even with relatively small amounts of Mn and Co, and avoids pore blocking caused by large Mn and Co contents.

[0036] In the present invention, the content of a portion of Mn and Co calculated as MnCo2O4 and the content of the remaining Mn calculated as MnO2 are obtained by ICP testing, and the specific testing method is as described above. Part of Mn exists in the form of MnO2, and part of Mn and Co exist in the form of MnCo2O4. The contents of Co and Mn are obtained by ICP testing, and then the content of a portion of Mn and Co calculated as MnCo2O4 is calculated using Co. The difference between the Mn content obtained by ICP testing and the amount of Mn existing in the form of MnCo2O4 is the content of the remaining Mn calculated as MnO2.

[0037] According to the present invention, preferably, the thickness of the modified alumina coating is 20 μm to 50 μm, more preferably 25 to 35 μm.

[0038] In the present invention, the thickness of the modified alumina coating is measured by SEM imaging using a thermal field emission scanning electron microscope SU5000 from Hitachi, Japan, with operating parameters of 30 kV resolution for secondary electron microscopy imaging, 15 kV resolution for backscattered electrons, and a beam current of 0-200 nA.

[0039] According to the present invention, preferably, the specific surface area of ​​the modified alumina coating is 100 to 200 m 2 By adopting this preferred embodiment, the modified alumina coating provides a larger specific surface area, which is more conducive to the subsequent dispersion of precious metals.

[0040] According to the present invention, preferably, the average pore size of the modified alumina coating is 5 to 12 nm. The modified alumina coating provided by the present invention has a larger average pore size, avoiding the pore blocking phenomenon caused by high Mn and Co contents in the prior art.

[0041] The present invention uses a physical adsorption analyzer, the AUTO-SORB-1-MP analyzer from Quantachrome, to measure the specific surface area and average pore size of the sample. Operating conditions: Before testing, the sample was vacuum degassed at 300°C for 6 hours on an external degassing station. Subsequently, adsorption and desorption tests were performed at liquid ammonia temperature (77 K) using nitrogen as the adsorbate. The specific surface area of ​​the sample was calculated using the Büninauer-Emmett-Teller (BET) method.

[0042] According to the catalytic material provided by the present invention, the coating layer containing aluminum oxide may be composed entirely of aluminum oxide, or may further contain other heat-resistant inorganic oxides. Preferably, the coating layer containing aluminum oxide further contains a heat-resistant inorganic oxide, and the heat-resistant inorganic oxide is at least one selected from silicon oxide, titanium oxide, cerium oxide, lanthanum oxide, and zirconium oxide, preferably silicon oxide.

[0043] The present invention has a wide range of selection for the content of alumina and other heat-resistant inorganic oxides in the coating containing alumina. Preferably, based on the total amount of the modified alumina coating, the content of the heat-resistant inorganic oxide (preferably silicon oxide) is 2 to 5 wt%, for example, 2 wt%, 3 wt%, 4 wt% or 5 wt%.

[0044] According to the present invention, the coating containing aluminum oxide preferably further contains a transition metal oxide, wherein the transition metal is selected from at least one of Group IIIB metal elements, Group IVB metal elements, and Group VB metal elements. The Group IIIB metal elements include, but are not limited to, Y and lanthanide metals. The Group IVB metal elements include, but are not limited to, Ti and Zr. The Group VB metal elements include, but are not limited to, V, Nb, and Ta.

[0045] According to a preferred embodiment of the present invention, the transition metal is more preferably at least one of cerium, lanthanum, zirconium and vanadium.

[0046] The present invention has a wide selection range for the content of the transition metal oxide. Preferably, based on the total amount of the modified alumina coating, the content of the transition metal oxide is 2-10 wt%.

[0047] According to a preferred embodiment of the present invention, the coating layer containing aluminum oxide includes aluminum oxide, silicon oxide, and a transition metal oxide. Based on the total amount of the coating layer containing aluminum oxide, the aluminum oxide content is 85-93 wt%, for example, 85 wt%, 86 wt%, 87 wt%, 88 wt%, 89 wt%, 90 wt%, 91 wt%, 92 wt%, or 93 wt%. The silicon oxide content is 2-5 wt%, for example, 2 wt%, 3 wt%, 4 wt%, or 5 wt%. The transition metal oxide content is 2-10 wt%, for example, 2 wt%, 3 wt%, 4 wt%, 5 wt%, 6 wt%, 7 wt%, 8 wt%, 9 wt%, or 10 wt%. This preferred embodiment is more conducive to improving the catalytic activity of the catalytic material.

[0048] The content of each component in the coating containing aluminum oxide can be obtained through ICP testing.

[0049] According to a preferred embodiment of the present invention, the manganese-cobalt composite oxide has a morphology of spherical or quasi-spherical particles formed by cross-stacked rod-like structures. As shown in FIG4 , the rod-like structures are irregularly cross-stacked to form spherical or quasi-spherical particles.

[0050] According to the present invention, preferably, the size (also referred to as diameter) of the spherical or quasi-spherical particles is 200 nm to 2 μm, preferably 200 nm to 500 nm.

[0051] According to the present invention, preferably, the length of the rod-like structure is 20 nm to 200 nm.

[0052] In the present invention, the morphology of the manganese-cobalt composite oxide is obtained by scanning electron microscopy.

[0053] According to the present invention, preferably, the surface layer of the rod-like structure is MnO2, and the interior is MnCo2O4. Further preferably, the thickness of the surface layer of the rod-like structure MnO2 is 1nm to 3nm.

[0054] The present invention uses STEM to observe the sample morphology and particle size distribution to calculate the particle size, and EDS to observe the element distribution of the sample. A JEM-F200 field emission transmission electron microscope from JEOL (JEOL) was used. Operating conditions: an accelerating voltage of 200kV. Before the test, a small amount of powder sample was ultrasonically dispersed in anhydrous ethanol and dripped onto a copper mesh using a capillary. The test was performed after drying. As shown in FIG5 , the strip-shaped particles with lattice spacings of 0.478nm and 0.293nm are the (111) and (220) crystal planes of MnCo2O4. It can be clearly seen that their outer layers, especially the outer layer of the (220) crystal plane, have a MnO2 thin layer with a spacing of 0.211nm. This indicates that the surface layer of the rod-shaped structure is MnO2 and the interior is MnCo2O4.

[0055] According to the present invention, the manganese-cobalt composite oxide is preferably grown on the coating containing aluminum oxide. In this preferred embodiment, the manganese-cobalt composite oxide and the coating containing aluminum oxide are tightly bonded. As shown in Figure 1, the manganese-cobalt composite oxide and the coating containing aluminum oxide have a cactus-like morphology (with pompoms growing above the leaves) and exhibit bonding.

[0056] According to a preferred embodiment of the present invention, in the Raman spectrum of the modified alumina coating, at 461 cm -1 、613cm -1 、679cm -1 There is a characteristic peak at 613cm -1 The characteristic peak intensity at 461 cm -1 and 679cm -1 The Raman spectra of the coating containing aluminum oxide and the manganese-cobalt composite oxide supported on the surface thereof show that the MnCo2O4 particles are obviously bonded to the aluminum oxide, and the two are tightly bonded.

[0057] In the present invention, the chemical environment of the metal is determined by Raman spectroscopy using a DRX microscope from Thermo Fisher, USA. Operating conditions: the excitation wavelength is λ ex. =532nm, detector is CCD, scanning range is 100-1000cm -1 , with a resolution of 1.0 cm -1 .

[0058] According to the monolithic catalytic material of the present invention, the structured support can provide a catalyst bed for a fixed bed reactor. The structured support can be a monolithic support block with a hollow pore structure formed inside. A coating containing aluminum oxide can be distributed on the inner wall of the pore, and the pore can be used as a flow space for the fluid. Preferably, the structured support is selected from a monolithic support having a parallel pore structure with openings at both ends. The structured support can be a honeycomb structured support (referred to as honeycomb ceramic) with a honeycomb-shaped opening in the cross section.

[0059] Preferably, the regular structure support body is a honeycomb ceramic; further preferably, the regular structure support body is selected from at least one of a cordierite honeycomb support, a mullite honeycomb support, a diamond honeycomb support, a corundum honeycomb support, a zirconium corundum honeycomb support, a quartz honeycomb support, a nepheline honeycomb support, a feldspar honeycomb support, an alumina honeycomb support and a metal alloy honeycomb support.

[0060] A second aspect of the present invention provides a method for preparing a monolithic catalytic material, the method comprising the following steps:

[0061] (1) introducing a coating slurry containing aluminum oxide and / or its precursor into a structured support, followed by drying and optionally calcining to obtain a structured support loaded with a coating containing aluminum oxide;

[0062] (2) The structured support carrying the coating layer containing aluminum oxide is reacted with a manganese precursor and a cobalt precursor in the presence of a solvent, and then dried.

[0063] According to the method provided by the present invention, the selection range of the regular structure support can be the same as the selection range of the first aspect mentioned above, and the present invention will not be repeated here.

[0064] According to the present invention, the structured support is preferably pretreated before step (1) to facilitate slurry adhesion. The specific operation and conditions of the pretreatment can be carried out according to conventional techniques in the art. Preferably, the pretreatment is carried out with an acid, particularly nitric acid (preferably a nitric acid concentration of 0.2 to 1 mol / L, and a pretreatment time of 4 to 8 hours). More preferably, washing and drying are performed after the pretreatment.

[0065] According to the method provided by the present invention, the precursor of the aluminum oxide can be any substance that can be converted into aluminum oxide by subsequent calcination, including but not limited to at least one of pseudo-boehmite, aluminum hydroxide and aluminum sec-butoxide.

[0066] The present invention has no particular limitation on the specific method of introducing the coating slurry into the structured support, and it can be, for example, coating or dipping, preferably dipping.

[0067] The coating may be performed once or multiple times as long as a desired amount of aluminum oxide-containing coating layer can be obtained.

[0068] The immersion time may be 2 to 10 minutes.

[0069] According to the method provided by the present invention, the coating slurry preferably contains the components and / or precursors of the components containing aluminum oxide coating described in the first aspect above.

[0070] According to a preferred embodiment of the present invention, the coating slurry contains aluminum oxide and a solvent and optionally a surfactant, optionally an aluminum oxide precursor, and optionally a silicon source. The coating slurry may contain any one of the surfactant, the aluminum oxide precursor, and the silicon source, or may not contain them, but preferably contains them.

[0071] Preferably, based on the total amount of the coating slurry, the content of the solvent is 40-70wt%, the content of the aluminum oxide is 15-45wt%, the content of the surfactant is 0-6wt%, the content of the aluminum oxide precursor is 0-6wt%, and the content of the silicon source is 0-6wt%. Further preferably, based on the total amount of the coating slurry, the content of the solvent is 45-65wt%, the content of the aluminum oxide is 20-40wt%, the content of the surfactant is 3-6wt%, the content of the aluminum oxide precursor is 3-6wt%, and the content of the silicon source is 3-6wt%. The use of the above preferred coating slurry formula is more conducive to the reaction of step (2), can form a stronger interaction between the active center and the coating, and effectively reduce the agglomeration and inactivation of the active components during the reaction process.

[0072] According to the present invention, preferably, the alumina precursor is pseudo-boehmite. More preferably, the specific surface area of ​​the pseudo-boehmite is 150 to 380 m 2 / g.

[0073] According to the present invention, preferably, the specific surface area of ​​the alumina is 100 to 1000 m 2 / g.

[0074] The alumina and pseudo-boehmite can be commercially available products or prepared according to existing technologies.

[0075] In the present invention, the surfactant can be selected from a wide range of types, so as to achieve uniform dispersion of the slurry components. Preferably, the surfactant is selected from at least one of polyethylene glycol, urea, sodium dodecylbenzene sulfonate, and stearic acid.

[0076] According to a preferred embodiment of the present invention, the silicon source is an organic silicon source, more preferably at least one of ethyl orthosilicate, methyl orthosilicate, polysiloxane and ethoxysiloxane.

[0077] In the present invention, the solvent can be selected from a wide range of types, as long as it can provide an environment for mixing with the other components in the slurry. Preferably, the solvent is water and / or a lower carbon alcohol, preferably water and a lower carbon alcohol. The lower carbon alcohol can be a C1-C5 alcohol, preferably one or more of ethanol, ethylene glycol, and butanol. Preferably, the mass ratio of the lower carbon alcohol to water is 1 to 2:20.

[0078] According to the present invention, preferably, the pH value of the coating slurry is 3 to 4, and / or the viscosity of the coating slurry is 10 to 100 mPa·s.

[0079] According to the present invention, the pH value of the coating slurry can be adjusted by adding acid or alkali, preferably by adding an inorganic acid solution, such as at least one of nitric acid, sulfuric acid and hydrochloric acid.

[0080] In the present invention, there is no particular limitation on the amount of the inorganic acid solution, as long as the pH value of the coating slurry is 3-4. Those skilled in the art can select the amount according to actual needs. In the present invention, the amount of the inorganic acid solution and the total amount of the other components in the coating slurry meet 100%.

[0081] In the present invention, the viscosity of the coating slurry refers to the viscosity measured by a viscometer at 25°C.

[0082] The coating slurry formulation according to the above preferred embodiment is more conducive to the close bonding of the manganese-cobalt composite oxide and the coating, and is more conducive to improving the subsequent performance in the catalytic oxidation reaction.

[0083] According to the present invention, the coating slurry preferably further comprises a transition metal, wherein the transition metal is selected from at least one of Group IIIB metal elements, Group IVB metal elements, and Group VB metal elements. The specific type of the transition metal can be selected from the same range as described in the first aspect above, and the present invention will not be further described here.

[0084] The present invention does not particularly limit the method for introducing the transition metal into the coating slurry, as long as the transition metal can be introduced into the coating containing aluminum oxide. Preferably, the transition metal can be added to the coating slurry in the form of a transition metal salt and mixed with other components, or can be introduced by supporting it on aluminum oxide.

[0085] According to the present invention, preferably, the coating slurry further contains a transition metal salt. More preferably, the content of the transition metal salt is 1 to 5 wt % based on the total amount of the coating slurry.

[0086] According to one embodiment of the present invention, a method for preparing a coating slurry includes uniformly mixing alumina powder, pseudo-boehmite, a surfactant, a silicon source, and a solvent, and then adjusting the pH to 3-4 or the viscosity to 10-100 mPa.s. The pH is typically adjusted using a diluted inorganic acid solution to obtain a slurry having a suitable viscosity.

[0087] According to the present invention, preferably, the reaction in step (2) is an oxidation-reduction reaction, which obtains a manganese-cobalt composite oxide on the surface of the coating containing aluminum oxide, and the coating containing aluminum oxide and the manganese-cobalt composite oxide form a modified aluminum oxide coating.

[0088] Preferably, the thickness of the modified alumina coating is 20 μm to 50 μm.

[0089] According to the present invention, preferably, the amounts of the coating slurry, the regular structure support, the manganese precursor and the cobalt precursor are such that in the prepared integral catalytic material, based on the total amount of the integral catalytic material, the content of the regular structure support is 80 to 95 wt%, preferably 85 to 92 wt%, and the total content of the modified alumina coating is 5 to 20 wt%, preferably 8 to 15 wt%.

[0090] According to the present invention, preferably, the amount of the coating slurry, manganese precursor and cobalt precursor is such that in the obtained integral catalytic material, based on the total amount of the modified alumina coating, the content of the coating containing alumina is 85-95wt%, and the content of the manganese-cobalt composite oxide is 5-15wt%.

[0091] Preferably, the manganese precursor and the cobalt precursor are used in such an amount that, in the resulting monolithic catalytic material, the content of a portion of Mn and Co calculated as MnCo2O4 is 5-15 wt%, and the content of the remaining Mn calculated as MnO2 is 0.1-1 wt%, based on the total amount of the modified alumina coating. The content of a portion of Mn and Co calculated as MnCo2O4 and the content of the remaining Mn calculated as MnO2 have the same meanings as described above in the first aspect.

[0092] According to the method provided by the present invention, the manganese precursor can be any manganese-containing compound that can undergo redox reaction. Preferably, the manganese precursor is potassium permanganate.

[0093] Similarly, the cobalt precursor can be any cobalt-containing compound that can undergo redox reaction. Preferably, the cobalt precursor is a divalent cobalt salt, such as cobalt nitrate, cobalt chloride, or cobalt sulfate. In the embodiment of the present invention, cobalt nitrate is used as an example for illustration.

[0094] The present invention has a wide range of choices for the solvent in step (2), as long as it provides an environment for the reaction. Preferably, the solvent is water.

[0095] According to a preferred embodiment of the present invention, the reaction in step (2) comprises contacting the structured support carrying the coating containing aluminum oxide with a solution containing a manganese precursor, and then adding a cobalt precursor to react. This preferred embodiment is more conducive to the redox reaction and is more conducive to obtaining a catalytic material with improved performance.

[0096] According to the method provided by the present invention, preferably, the concentration of the solution containing the manganese precursor is 0.1-0.3 mol / L.

[0097] According to the method provided by the present invention, preferably, in step (2), the regular structure support loaded with the coating containing aluminum oxide is contacted with the solution containing a manganese precursor by immersing the regular structure support loaded with the coating containing aluminum oxide in the solution containing a manganese precursor.

[0098] Preferably, the cobalt precursor is added in the form of a solution containing the cobalt precursor.

[0099] Preferably, the concentration of the solution containing the cobalt precursor is 1 to 8 times the concentration of the solution containing the manganese precursor.

[0100] According to the method provided by the present invention, the addition rate of the solution containing the cobalt precursor can be selected in a wide range, based on the condition that it is conducive to the redox reaction. Preferably, the addition rate of the solution containing the cobalt precursor is 0.5% to 1% of the total volume of the solution containing the cobalt precursor per minute.

[0101] According to a preferred embodiment of the present invention, step (2) comprises contacting the structured support carrying the coating containing aluminum oxide with a solution containing a manganese precursor, heating the solution to a reaction temperature, and then adding the cobalt precursor to react; preferably, the reaction temperature is 50 to 90° C., preferably 60 to 80° C.; preferably, the reaction time is 1 to 6 hours, preferably 2 to 4 hours. The reaction time is measured from the completion of the addition of the cobalt precursor.

[0102] According to a preferred embodiment of the present invention, in order to facilitate the redox reaction, the step of adding the cobalt precursor in step (2) is carried out under oscillation conditions. The present invention has a wide range of oscillation conditions, and preferably, the oscillation frequency is 60 to 180 times / minute.

[0103] The method provided by the present invention specifically further comprises a washing step performed before the drying in step (2). The washing can be performed using conventional technical means in the art, and the present invention has no particular limitation thereto.

[0104] According to the present invention, preferably, the drying conditions in step (1) and step (2) independently include: a temperature of 100 to 150° C. and a time of 8 to 24 hours.

[0105] According to the present invention, the calcination may be performed in step (1) or not. Preferably, the calcination conditions in step (1) include: a calcination temperature of 250-500°C, preferably 300-380°C, and a calcination time of 1-6 hours, preferably 2-4 hours.

[0106] The third aspect of the present invention provides a monolithic catalyst, which comprises the monolithic catalytic material described in the first aspect or the monolithic catalytic material prepared by the preparation method described in the second aspect, and a precious metal component.

[0107] Preferably, the precious metal component is selected from at least one of platinum, palladium, rubidium and rhodium, more preferably platinum and / or palladium, and most preferably platinum and palladium. The present invention has a wide range of selection for the ratio of platinum to palladium, for example, it can be 1:0.1 to 10.

[0108] According to the present invention, preferably, the content of the precious metal component is 0.2 to 2.5 g / L based on the total volume of the monolithic catalyst. The use of the monolithic catalytic material provided by the present invention can reduce the amount of precious metal components used.

[0109] According to the present invention, preferably, the average particle diameter of the noble metal component is 4 to 10 nm, more preferably 4 to 8 nm, for example, 4 nm, 5 nm, 6 nm, 7 nm or 8 nm. The noble metal component of the catalyst provided by the present invention is better dispersed and has a smaller average particle diameter.

[0110] In the present invention, the average particle diameter of the precious metal component was determined by STEM observation of sample morphology and particle size distribution using a JEOL JEM-F200 field emission transmission electron microscope. Operating conditions: an accelerating voltage of 200 kV. Prior to testing, a small amount of powder sample was ultrasonically dispersed in anhydrous ethanol and dripped onto a copper grid using a capillary tube. The sample was then dried before testing.

[0111] The present invention has no particular limitation on the preparation method of the monolithic catalyst, and the monolithic catalyst may be prepared by any of the methods conventionally used in the art, such as an ammonia decomposition method.

[0112] The fourth aspect of the present invention provides a method for preparing an integral catalyst, which comprises impregnating the integral catalytic material described in the first aspect or the integral catalytic material prepared by the preparation method described in the second aspect in an impregnation solution containing a precious metal precursor, adjusting the pH to alkaline, allowing to stand, and then drying and calcining.

[0113] Preferably, the standing time is 1 to 6 hours.

[0114] Preferably, the preparation method further comprises: heating the product obtained after standing.

[0115] Preferably, the conditions for the heat treatment include: a temperature of 50 to 80° C., preferably 60 to 70° C., and a time of 1 to 6 hours.

[0116] Preferably, the drying conditions include: a temperature of 100 to 150° C. and a time of 12 to 24 hours.

[0117] Preferably, the calcination conditions include: a calcination temperature of 400-550° C., and a calcination time of 1-6 hours, preferably 2-4 hours.

[0118] In the present invention, ammonia can be used to adjust the pH to alkaline, preferably to 8-9. Preferably, the concentration of ammonia is 0.5-1 mol / L. Using ammonia to adjust the pH facilitates the dispersion of the precious metal and improves the catalytic performance of the catalyst.

[0119] A fifth aspect of the present invention provides use of the monolithic catalytic material described in the first aspect or the monolithic catalyst described in the third aspect in a catalytic oxidation reaction, preferably in a catalytic oxidation reaction of VOCs. The monolithic catalytic material or monolithic catalyst provided by the present invention is suitable for treating a variety of industrial waste gases, and is particularly suitable for treating VOCs contained in waste gases from the petroleum refining and chemical industries.

[0120] The sixth aspect of the present invention provides a method for catalytic oxidation of VOCs, which comprises contacting exhaust gas containing VOCs with the integral catalyst described in the third aspect to carry out a catalytic oxidation reaction.

[0121] Preferably, the conditions of the catalytic oxidation reaction include: reaction pressure is atmospheric pressure, reaction temperature is 200-600°C, exhaust gas volume space velocity is 5000-60000h -1 .

[0122] Preferably, the concentration of VOCs in the exhaust gas containing VOCs is 500 to 10,000 ppmv.

[0123] The present invention has a wide range of selection for the types of VOCs substances, which can be one or more substances selected from alkanes, olefins, benzene series, oxygen-containing VOCs and chlorine-containing VOCs.

[0124] In the present invention, the reaction can be carried out in a fixed bed reactor.

[0125] The preparation process and product performance of the method of the present invention are further illustrated below in conjunction with examples and comparative examples, but the following examples do not constitute a limitation of the method of the present invention.

[0126] The pseudo-boehmite used in the following examples is SB powder with a specific surface area of ​​350 m 2 / g, alumina powder is obtained by calcining SB powder at 540℃, with a specific surface area of ​​300m 2 / g, the honeycomb ceramic used in the embodiment is a 400-mesh cordierite honeycomb ceramic. The honeycomb ceramic is pretreated before use. The pretreatment process is to place 100 mL of the honeycomb ceramic in 200 mL of 1 mol / L nitric acid solution and vibrate in an ultrasonic oscillator for 1 hour; then repeatedly rinse with 500 mL of clean water, and then dry in an oven at 110°C for 12 hours.

[0127] Example 1

[0128] (1) A 3 wt % aqueous solution of cerium nitrate, alumina powder, urea, pseudo-boehmite, butanol, and ethyl orthosilicate were stirred and uniformly mixed in a material mass ratio of (170:90:10:10:18:10) to obtain a mixed slurry; and the pH was adjusted to 3.5;

[0129] (2) Immersing the pretreated honeycomb ceramic in the mixed slurry for 2 minutes, blowing the slurry residue out of the pores after taking it out, drying it at 110°C for 12 hours, and calcining it at 350°C for 4 hours to obtain a monolithic catalyst carrier;

[0130] (3) The monolithic catalyst support obtained in step (2) was immersed in 100 mL of 0.2 mol / L potassium permanganate solution, and then heated to 70°C, and 50 mL of 0.8 mol / L cobalt nitrate solution was added dropwise. During the process, a beaker oscillator was used to oscillate at a frequency of 60 times / min. After that, the monolithic catalyst support was kept still for 4 hours, taken out, purged with dry air for 2 hours, and then dried at 110°C for 8 hours to obtain a monolithic catalytic material A.

[0131] The monolithic catalytic material A comprises a honeycomb ceramic and a modified alumina coating (including a coating containing alumina and a manganese-cobalt composite oxide) distributed on the honeycomb ceramic. Based on the total amount of the catalytic material, the content of the honeycomb ceramic is 88 wt%, and the content of the modified alumina coating is 12 wt%. The specific surface area of ​​the modified alumina coating is 150 m 2 / g, average pore size 7.8nm.

[0132] Based on the total amount of the modified alumina coating, it includes part of Mn calculated as MnO2 with a content of 0.2wt%, part of Mn and Co calculated as MnCo2O4 with a content of 10wt%, Si calculated as SiO2 with a content of 2wt%, Al calculated as Al2O3 with a content of 85wt%, and Ce calculated as CeO2 with a content of 3wt%.

[0133] After characterization, it can be seen from Figures 1, 4 and 5 that the surface of the coating is uniformly loaded with spherical particles of manganese-cobalt composite oxide, the diameter of the spherical particles is 200nm~500nm, the length of the rod-like structure on the surface of the spherical particles is 20nm~40nm, the inside of the rod-like structure is MnCo2O4, the outer layer is MnO2, the thickness of MnO2 is 1~3nm, and the thickness of the modified alumina coating is 25μm~30μm; Figure 1 is an SEM image of the integral catalytic material A, from which it can be seen that the manganese-cobalt composite oxide is tightly combined with the coating, has a morphology similar to that of cactus balls, and has a bonding phenomenon.

[0134] FIG2 is the XRD spectrum of the integral catalytic material A. As can be seen from FIG2 , after MnCo2O4 is combined with alumina, the diffraction peaks of both are weakened, and it can be seen that there is a certain degree of combination between the two.

[0135] Figure 3 is the Raman spectrum of the monolithic catalytic material A. It can be seen that at 461 cm -1 、613cm -1 、679cm -1 There is a characteristic peak at 613cm -1 The characteristic peak intensity at 461 cm -1 and 679cm -1 The characteristic peak intensity shows that the MnCo2O4 particles are obviously bonded with alumina, and the two are closely bonded.

[0136] FIG4 is a SEM image of the monolithic catalytic material A. As can be seen from FIG4 , the morphology of the manganese-cobalt composite oxide is spherical or quasi-spherical particles formed by cross-stacked rod-like structures.

[0137] Figure 5 shows a STEM image of monolithic catalytic material A. The rod-shaped particles with lattice spacings of 0.478 nm and 0.293 nm are the (111) and (220) planes of MnCo2O4. Their outer layers, especially the outer layer of the (220) plane, are clearly visible, with a thin MnO2 layer with a spacing of 0.211 nm. This indicates that the surface of the rod-shaped structure is MnO2, while the interior is MnCo2O4.

[0138] (4) The monolithic catalytic material A obtained in step (3) was immersed in 100 mL of a 0.66 g / L platinum nitrate and 0.33 g / L palladium nitrate solution, concentrated ammonia was added to adjust the pH to 8-9, and then allowed to stand for 2 hours, and then heated at 70° C. for 1 hour;

[0139] (5) After taking out the honeycomb ceramic catalyst in step (4), it was purged with dry air for 2 hours, then dried at 110°C for 12 hours, and then calcined at 450°C for 4 hours to obtain the catalyst MnCo-1.

[0140] Example 2

[0141] (1) A 5 wt% aqueous solution of cerium nitrate, alumina powder, urea, pseudo-boehmite, butanol, and ethyl orthosilicate were stirred and uniformly mixed in a material mass ratio of (170:90:10:10:18:12) to obtain a mixed slurry; and the pH was adjusted to 3;

[0142] (2) Immersing the pretreated honeycomb ceramic in the mixed slurry for 2 minutes, blowing the slurry residue out of the pores after taking it out, drying it at 110°C for 15 hours, and calcining it at 360°C for 2 hours to obtain a monolithic catalyst carrier;

[0143] (3) The monolithic catalyst support obtained in step (2) was immersed in 100 mL of 0.2 mol / L potassium permanganate solution, then heated to 70°C, and 50 mL of 1 mol / L cobalt nitrate solution was added dropwise. During the process, a beaker oscillator was used to oscillate at a frequency of 60 times / min. After that, the monolithic catalyst support was kept still for 4 hours, taken out, purged with dry air for 2 hours, and then dried at 110°C for 12 hours to obtain a monolithic catalytic material B.

[0144] The monolithic catalytic material B comprises a honeycomb ceramic and a modified alumina coating (including a coating containing alumina and a manganese-cobalt composite oxide) distributed on the honeycomb ceramic. Based on the total amount of the catalytic material, the content of the honeycomb ceramic is 85wt%, and the content of the modified alumina coating is 15wt%. The specific surface area of ​​the modified alumina coating is 170m 2 / g, average pore size 7.3nm.

[0145] Based on the total amount of the modified alumina coating, it includes a portion of Mn calculated as MnO2 with a content of 0.2wt%, a portion of Mn and Co calculated as MnCo2O4 with a content of 11wt%, Si calculated as SiO2 with a content of 2.4wt%, Al calculated as Al2O3 with a content of 81.4wt%, and Ce calculated as CeO2 with a content of 5wt%.

[0146] (4) The monolithic catalytic material B obtained in step (3) was immersed in 100 mL of a 0.66 g / L platinum nitrate and 0.33 g / L palladium nitrate solution, concentrated ammonia was added to adjust the pH to 8-9, and then allowed to stand for 2 hours, and then heated at 75° C. for 1.5 hours;

[0147] (5) After taking out the honeycomb ceramic catalyst in step (4), it was purged with dry air for 2 hours, then dried at 110°C for 12 hours, and then calcined at 450°C for 4 hours to obtain the catalyst MnCo-2.

[0148] Example 3

[0149] Steps (1) and (2) were carried out according to Example 1.

[0150] (3) The monolithic catalyst support obtained in step (2) was immersed in 100 mL of 0.1 mol / L potassium permanganate solution, then heated to 70°C, and 50 mL of 0.6 mol / L cobalt nitrate solution was added dropwise. During the process, a beaker oscillator was used to oscillate at a frequency of 60 times / min. After that, the monolithic catalyst support was kept still for 4 hours, taken out, purged with dry air for 2 hours, and then dried at 110°C for 8 hours to obtain a monolithic catalytic material C.

[0151] The monolithic catalytic material C comprises a honeycomb ceramic and a modified alumina coating (including a coating containing alumina and a manganese-cobalt composite oxide) distributed on the honeycomb ceramic. Based on the total amount of the catalytic material, the honeycomb ceramic content is 89 wt%, and the modified alumina coating content is 11 wt%.

[0152] Based on the total amount of the modified alumina coating, it includes part of Mn calculated as MnO2 with a content of 0.1wt%, part of Mn and Co calculated as MnCo2O4 with a content of 5wt%, Si calculated as SiO2 with a content of 2wt%, Al calculated as Al2O3 with a content of 90wt%, and Ce calculated as CeO2 with a content of 3wt%.

[0153] SEM and STEM characterizations show that the coating surface is uniformly loaded with spherical particles of manganese-cobalt composite oxide, with a diameter of 200nm to 500nm, a rod-like structure on the surface of the spherical particles with a length of 20nm to 40nm, MnCo2O4 inside the rod-like structure and MnO2 on the outside, and a MnO2 thickness of 1 to 2nm. The thickness of the modified alumina coating is 25μm to 30μm.

[0154] (4) The monolithic catalytic material C obtained in step (3) was immersed in 100 mL of 1 g / L platinum nitrate solution, concentrated ammonia was added to adjust the pH to 8-9, and then allowed to stand for 2 hours, and then heated at 70° C. for 1 hour;

[0155] (5) After taking out the honeycomb ceramic catalyst in step (4), it was purged with dry air for 2 hours, then dried at 110°C for 12 hours, and then calcined at 450°C for 4 hours to obtain the catalyst MnCo-3.

[0156] Example 4

[0157] The method of Example 1 was followed, except that the cerium nitrate aqueous solution was replaced with an equal mass of water to obtain the catalyst MnCo-4.

[0158] Example 5

[0159] The method of Example 1 was followed, except that 100 mL of potassium permanganate solution was replaced with 100 mL of manganese nitrate solution. The catalyst MnCo-5 was obtained.

[0160] The resulting catalyst cannot be loaded with significant amounts of Mn and Co via chemical reduction. Only small amounts of Mn and Co are loaded in the form of MnO2 and Co3O4, respectively. Based on the total amount of the modified alumina coating, the coating comprises 0.1 wt% Mn as MnO2, 0.2 wt% Co as Co3O4, 2 wt% Si as SiO2, 95 wt% Al as Al2O3, and 3 wt% Ce as CeO2.

[0161] Example 6

[0162] The method of Example 1 was followed, except that no ethyl orthosilicate was added in step (1), to obtain the catalyst MnCo-6.

[0163] Example 7

[0164] The method of Example 1 was followed, except that the mass ratio of 3 wt % cerium nitrate aqueous solution, alumina powder, urea, pseudo-boehmite, butanol, and tetraethyl orthosilicate was 170:90:10:10:18:60 to obtain catalyst MnCo-7.

[0165] Example 8

[0166] The method of Example 1 was followed, except that in step (3), potassium permanganate solution and cobalt nitrate solution were added simultaneously, and reacted in an autoclave at 160° C. and 1 MPa pressure to obtain the catalyst MnCo-8.

[0167] SEM characterization shows that the coating surface is loaded with spherical particles of manganese-cobalt composite oxide, the diameter of the spherical particles is 2μm to 5μm, and the rod-like structure on the surface of the spherical particles is not obvious. At the same time, the thickness of the modified alumina coating is 10μm, with obvious loss.

[0168] Example 9

[0169] The method of Example 1 was followed, except that, based on the same mass of silicon dioxide, ethyl orthosilicate was replaced with silica sol of the same mass to obtain catalyst MnCo-9.

[0170] Example 10

[0171] The method of Example 1 is followed, except that step (4) and step (5) are not included, and after drying in step (3), the catalyst is calcined at 450° C. for 4 hours to obtain catalyst MnCo-10.

[0172] Comparative Example 1

[0173] The method of Example 1 is followed, except that steps (1) and (2) are not included, and the honeycomb ceramic body is directly used as a carrier for the subsequent steps.

[0174] Table 1

[0175] Note: The mass fraction of Mn in Table 1 is based on the total amount of the catalyst.

[0176] Test Example 1

[0177] The catalysts of the examples and comparative examples were applied to the catalytic oxidation of ethane in a fixed-bed reactor of a medium-sized reaction evaluation device. The catalyst loading was 100 mL, the bed height was 10 cm, the initial ethane concentration was 2000 ppm, the carrier gas was air, and the space velocity was 20,000 h-1. -1 The ethane concentration was measured using an Agilent 7890A gas chromatograph, and the test results are shown in Table 2. Under the same conditions, benzene was used as the reactant, with an initial benzene concentration of 3000 ppm, and the test results are shown in Table 3.

[0178] Table 2

[0179] Table 3

[0180] Test Example 2

[0181] This test example is used to illustrate the stability of the monolithic catalytic material A obtained in Example 1. The test conditions include: monolithic catalytic material A loading amount 100 mL, reaction temperature 350 ° C, gas volume space velocity 6000 h -1 , using an ethane concentration of 1300ppm and air as the carrier gas. Figure 6 is a stability evaluation curve of the integral catalytic material A of Example 1, wherein the horizontal axis is the reaction time and the vertical axis is the conversion rate of ethane. Among them, the black (lower) curve refers to the curve obtained under the condition of introducing 5% by volume of water vapor (w / H2O addition), and the red (upper) curve refers to the curve obtained under the condition of not introducing water vapor (w / o H2O addition). It can be seen that 50 hours after the start of the reaction, the catalytic material entered a stable state. Whether water vapor is introduced or not, its activity does not decrease, indicating that the catalytic material provided by the present invention has good stability.

Claims

1. An integral catalytic material, characterized in that, It includes a regular structure support and a modified alumina coating distributed on the regular structure support. The modified alumina coating includes a coating containing alumina and a manganese-cobalt composite oxide supported on the surface of the coating containing alumina.

2. The catalytic material according to claim 1, wherein Based on the total amount of the monolithic catalytic material, the content of the regular structure support is 80-95 wt%, preferably 85-92 wt%, and the content of the modified alumina coating is 5-20 wt%, preferably 8-15 wt%; Preferably, based on the total amount of the modified alumina coating, the content of the coating containing alumina is 85-95 wt%, and the content of the manganese-cobalt composite oxide is 5-15 wt%; More preferably, based on the total amount of the modified alumina coating, the content of part of Mn and Co calculated as MnCo2O4 is 4-15 wt%, and the content of the remaining part of Mn calculated as MnO2 is 0.1-1 wt%; More preferably, the thickness of the modified alumina coating is 20 μm-50 μm; Further preferably, the specific surface area of the modified alumina coating is 100-200 m 2 / g, and the average pore diameter is 5-12 nm.

3. The catalytic material according to claim 1 or 2, wherein The coating containing alumina also contains a heat-resistant inorganic oxide, and the heat-resistant inorganic oxide is selected from at least one of silicon oxide, titanium oxide, cerium oxide, lanthanum oxide, and zirconium oxide, preferably silicon oxide; Preferably, based on the total amount of the modified alumina coating, the content of the heat-resistant inorganic oxide is 2-5 wt%; Preferably, the coating containing alumina also contains a transition metal oxide, and the transition metal is selected from at least one of group IIIB metal elements, group IVB metal elements, and group VB metal elements, more preferably at least one of cerium, lanthanum, zirconium, and vanadium; Preferably, based on the total amount of the modified alumina coating, the content of the transition metal oxide is 2-10 wt%.

4. The catalytic material according to any one of claims 1-3, wherein, The morphology of the manganese-cobalt composite oxide is spherical or quasi-spherical particles formed by the cross-stacking of rod-like structures; Preferably, the size of the spherical or quasi-spherical particles is 200 nm-2 μm, preferably 200 nm-500 nm.

5. The catalytic material according to claim 4, wherein The length of the rod-like structure is 20 nm-200 nm; Preferably, the surface layer of the rod-like structure is MnO2, and the interior is MnCo2O4; More preferably, the thickness of the MnO2 on the surface layer of the rod-like structure is 1 nm-3 nm.

6. The catalytic material according to any one of claims 1-5, wherein, The manganese-cobalt composite oxide grows on the coating containing alumina.

7. The catalytic material according to any one of claims 1-6, wherein, In the Raman spectrum of the modified alumina coating, characteristic peaks exist at 461 cm -1 , 613 cm -1 , and 679 cm -1 . Moreover, the peak intensity of the characteristic peak at 613 cm -1 is stronger than the peak intensities of the characteristic peaks at 461 cm -1 and 679 cm -1 .

8. The catalytic material according to any one of claims 1-7, wherein, The regular structure support is selected from monolithic carriers having a parallel pore structure with both ends open; Preferably, the regular structure support is a honeycomb ceramic; Preferably, the regular structure support is selected from at least one of cordierite honeycomb carriers, mullite honeycomb carriers, diamond honeycomb carriers, corundum honeycomb carriers, zircon corundum honeycomb carriers, quartz honeycomb carriers, nepheline honeycomb carriers, feldspar honeycomb carriers, alumina honeycomb carriers, and metal alloy honeycomb carriers.

9. A preparation method of an integral catalytic material, characterized in that, The preparation method includes the following steps: (1) Introduce a coating slurry containing alumina and / or its precursor into the regular structure support, then dry and optionally calcine to obtain a regular structure support loaded with a coating containing alumina; (2) In the presence of a solvent, a structured support loaded with a coating containing alumina is reacted with a manganese precursor and a cobalt precursor, and then dried.

10. The preparation method according to claim 9, wherein, The reaction in step (2) is a redox reaction, and a manganese-cobalt composite oxide is obtained on the surface of the coating containing alumina. The coating containing alumina and the manganese-cobalt composite oxide form a modified alumina coating; Preferably, the thickness of the modified alumina coating is 20 μm to 50 μm; Preferably, the amounts of the coating slurry, the structured support, the manganese precursor, and the cobalt precursor are such that in the monolithic catalytic material obtained, based on the total amount of the monolithic catalytic material, the content of the structured support is 80 to 95 wt%, preferably 85 to 92 wt%, and the total content of the modified alumina coating is 5 to 20 wt%, preferably 8 to 15 wt%; Preferably, the amounts of the manganese precursor and the cobalt precursor are such that in the monolithic catalytic material obtained, based on the total amount of the modified alumina coating, the content of part of Mn and Co in terms of MnCo2O4 is 5 to 15 wt%, and the content of the remaining part of Mn in terms of MnO2 is 0.1 to 1 wt%; Preferably, in step (2), the molar ratio of the Mn precursor to the cobalt precursor in terms of metal elements is 0.1 to 0.8, more preferably 0.3 to 0.6; Preferably, the structured support is selected from monolithic carriers having a parallel pore structure with open ends at both ends; further preferably, the structured support is a honeycomb ceramic; more preferably, the structured support is selected from at least one of cordierite honeycomb carriers, mullite honeycomb carriers, diamond honeycomb carriers, corundum honeycomb carriers, zircon corundum honeycomb carriers, quartz honeycomb carriers, nepheline honeycomb carriers, feldspar honeycomb carriers, alumina honeycomb carriers, and metal alloy honeycomb carriers.

11. The preparation method according to claim 9 or 10, wherein The coating slurry contains alumina, a solvent, and optionally a surfactant, an optionally alumina precursor, and an optionally silicon source; Preferably, based on the total amount of the coating slurry, the content of the solvent is 40 to 70 wt%, the content of alumina is 15 to 45 wt%, the content of the surfactant is 0 to 6 wt%, the content of the alumina precursor is 0 to 6 wt%, and the content of the silicon source is 0 to 6 wt%; further preferably, based on the total amount of the coating slurry, the content of the solvent is 45 to 65 wt%, the content of alumina is 20 to 40 wt%, the content of the surfactant is 3 to 6 wt%, the content of the alumina precursor is 3 to 6 wt%, and the content of the silicon source is 3 to 6 wt%; Preferably, the alumina precursor is at least one of pseudo-boehmite, aluminum hydroxide, and aluminum sec-butoxide; Preferably, the specific surface area of the alumina is 100 to 1000 m 2 / g; Preferably, the specific surface area of the pseudo-boehmite is 150 to 380 m 2 / g; Preferably, the surfactant is selected from at least one of polyethylene glycol, urea, sodium dodecylbenzenesulfonate, and stearic acid; Preferably, the silicon source is an organosilicon source, further preferably at least one of tetraethyl orthosilicate, tetramethyl orthosilicate, polysiloxane, and ethoxysiloxane; Preferably, the pH value of the coating slurry is 3 to 4, and / or the viscosity of the coating slurry is 10 to 100 mPa·s.

12. The preparation method according to claim 11, wherein, The coating slurry further contains a transition metal salt, and the transition metal is selected from at least one of the Group IIIB metal elements, Group IVB metal elements, and Group VB metal elements, preferably at least one of cerium, lanthanum, zirconium, and vanadium; Preferably, based on the total amount of the coating slurry, the content of the transition metal salt is 1-5 wt%.

13. The preparation method according to any one of claims 9-12, wherein The manganese precursor is potassium permanganate; The cobalt precursor is a divalent cobalt salt; Preferably, the reaction in step (2) includes: contacting a structured support loaded with a coating containing alumina with a solution containing a manganese precursor, and then adding a cobalt precursor for reaction; Preferably, the concentration of the solution containing the manganese precursor is 0.1-0.3 mol / L; Preferably, the manner of contacting the structured support loaded with the coating containing alumina with the solution containing the manganese precursor in step (2) is to immerse the structured support loaded with the coating containing alumina in the solution containing the manganese precursor; Preferably, the cobalt precursor is added in the form of a solution containing the cobalt precursor, and the concentration of the solution containing the cobalt precursor is 1-8 times the concentration of the solution containing the manganese precursor.

14. The preparation method according to any one of claims 9-13, wherein Step (2) includes contacting the structured support loaded with the coating containing alumina with the solution containing the manganese precursor, then raising the temperature to the reaction temperature, and then adding the cobalt precursor for reaction; preferably, the reaction temperature is 50-90 °C, preferably 60-80 °C; preferably, the reaction time is 1-6 hours, preferably 2-4 hours.

15. The preparation method according to any one of claims 9-14, wherein The drying conditions in step (1) and step (2) each independently include: a temperature of 100-150 °C and a time of 8-24 hours; The calcination conditions in step (1) include: a calcination temperature of 250-500 °C and a time of 1-6 hours.

16. A monolithic catalyst, which includes the monolithic catalytic material according to any one of claims 1-8 or the monolithic catalytic material prepared by the preparation method according to any one of claims 9-15, and a noble metal component; Preferably, the noble metal component is selected from at least one of platinum, palladium, rubidium, and rhodium; Preferably, based on the total volume of the monolithic catalyst, the content of the noble metal component is 0.2-2.5 g / L; Preferably, the average particle diameter of the noble metal component is 4-10 nm.

17. A preparation method of a monolithic catalyst, which includes immersing the monolithic catalytic material according to any one of claims 1-8 or the monolithic catalytic material prepared by the preparation method according to any one of claims 9-15 in an impregnation solution containing a noble metal precursor, adjusting the pH to alkaline, preferably adjusting to a pH of 8-9, standing, and then performing drying and calcination; Preferably, the standing time is 1-6 hours; Preferably, the preparation method further comprises: subjecting the product obtained after standing to heat treatment; Preferably, the conditions of the heat treatment include: temperature of 50-80 °C and time of 1-6 hours; Preferably, the conditions of the drying include: temperature of 100-150 °C and time of 12-24 hours; Preferably, the conditions of the calcination include: calcination temperature of 400-550 °C and time of 1-6 hours.

18. Use of the monolithic catalytic material according to any one of claims 1-8 or the monolithic catalyst according to claim 16 in a catalytic oxidation reaction, preferably in a catalytic oxidation reaction of VOCs.

19. A method for catalytic oxidation of VOCs, the method comprising subjecting the waste gas containing VOCs to catalytic oxidation reaction by contacting with the monolithic catalyst according to claim 16; Preferably, the conditions for the catalytic oxidation reaction include: The reaction pressure is atmospheric pressure, the reaction temperature is 200 to 600 °C, and the volumetric space velocity of the waste gas containing VOCs is 5000 to 60000 h -1 ; Preferably, in the waste gas containing VOCs, the concentration of VOCs is 500-10000 ppmv.

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