A hollow structure catalyst for removing nitrogen oxides and chlorinated organic compounds in a reaction zone, and a preparation method and application thereof

Abstract

The application discloses a hollow-structure catalyst for removing nitrogen oxides and chlorinated organic compounds, a preparation method and application thereof, and relates to the technical field of environmental catalysis and multi-pollutant control. The hollow-structure catalyst for removing nitrogen oxides and chlorinated organic compounds is prepared by combining a hydrothermal method, a sol-gel method and an impregnation method. The catalyst has a hollow core-shell structure, and comprises a hollow spherical titanium dioxide shell layer, a composite active component of vanadium pentoxide and tungsten trioxide loaded on the inner surface of the hollow spherical titanium dioxide shell layer, and a composite active component of chromium sesquioxide and cerium dioxide loaded on the outer surface of the hollow spherical titanium dioxide shell layer. The catalyst separates active sites, realizes reaction partition of NH3-SCR reaction and catalytic oxidation reaction of chlorinated organic compounds, significantly improves the removal efficiency of nitrogen oxides and chlorinated organic compounds, and greatly reduces the generation of peroxide by-products in the reaction.

Description

Technical Field

[0001] This invention relates to the field of environmental catalysis for the control of multiple pollutants, and in particular to a hollow-structured catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones, its preparation method, and its application. Background Technology

[0002] Nitrogen oxides (NO) x Nitrogen oxides (NOx) and chlorinated volatile organic compounds (Cl-VOCs) are typical toxic and harmful pollutants in industrial flue gas. Chlorobenzene, as a representative Cl-VOC, is chemically stable, difficult to biodegrade, and easily generates highly carcinogenic byproducts such as dioxins and chlorinated aromatic hydrocarbons during high-temperature reactions. Both pose serious threats to the ecological environment and human health. Currently, selective catalytic reduction (NH3-SCR) is a mature technology for removing nitrogen oxides, and catalytic oxidation is the mainstream technology for removing Cl-VOCs. However, when multiple pollutants coexist in industrial flue gas, single-function catalysts cannot achieve removal. Traditional bifunctional catalysts, due to the lack of effective separation of active sites for denitrification and chlorobenzene oxidation, suffer from competitive adsorption problems in different reaction atmospheres. This not only leads to low removal efficiency of nitrogen oxides and chlorobenzene but also generates a large number of chlorinated byproducts and nitrogen oxide reduction byproducts due to mutual interference of active sites, resulting in a high risk of secondary pollution. For example, Chinese patent CN113000046A discloses a modified manganese-based mullite catalyst for the purification of nitrogen oxides and chlorinated volatile organic compounds, its preparation method, and its application. This invention uses modified metal elements (Ca, Sr, Ba, Fe, etc.), lanthanides (La, Ce, Sm, etc.), and manganese metal salts as main raw materials, combined with potassium permanganate, to prepare the catalyst via a hydrothermal method combined with surface acid etching. The process involves dissolving and mixing the metal salts, adjusting the pH to 1-12, hydrothermally reacting at 160-200℃ for 12-20 hours, calcining, etching with 0.1-3 mol / L acid solution, and secondary calcination. However, when catalyzing the reaction of nitrogen oxides and chlorobenzene, the catalyst's N2 selectivity is only about 80%, indicating that a large amount of peroxidation byproducts are still generated during the removal of nitrogen oxides and chlorobenzene. Therefore, designing a catalyst with excellent catalytic performance that can simultaneously and efficiently remove nitrogen oxides and Cl-VOCs is of great significance. Summary of the Invention

[0003] To address the technical problems of low removal efficiency of nitrogen oxides and chlorinated organic compounds in existing technologies, and the large number of byproducts caused by competitive adsorption between active sites under different reaction atmospheres, this invention provides a hollow-structured catalyst for the partial removal of nitrogen oxides and chlorinated organic compounds, its preparation method, and its application. This catalyst achieves physical isolation of active sites through a unique hollow core-shell structure design, which can effectively improve the removal efficiency of nitrogen oxides and chlorinated organic compounds and significantly reduce the amount of byproducts generated. The N2 selectivity of the catalyst is always maintained above 90%.

[0004] To achieve the above objectives, the present invention provides the following solution: One technical solution of the present invention is a hollow core-shell catalyst for the reaction partitioning removal of nitrogen oxides and chlorinated organic compounds. The catalyst has a hollow core-shell structure, comprising a hollow spherical titanium dioxide shell, a vanadium pentoxide and tungsten trioxide composite active component supported on the inner surface of the hollow spherical titanium dioxide shell (i.e., the vanadium pentoxide and tungsten trioxide composite active component is located inside the hollow spherical titanium dioxide shell, serving as the main active component for the NH3-SCR reaction), and a chromium trioxide and cerium dioxide composite active component supported on the outer surface of the hollow spherical titanium dioxide shell (i.e., the chromium trioxide and cerium dioxide composite active component is located outside the hollow spherical titanium dioxide shell, serving as the main active component for the catalytic oxidation reaction of chlorinated organic compounds). In other words, the core of the catalyst is a cavity, and the outer shell is a spherical titanium dioxide shell with different composite active components loaded on its inner and outer surfaces respectively.

[0005] The catalyst of this invention has a hollow core-shell structure, consisting of, from the inside out, a composite active component of vanadium pentoxide and tungsten trioxide for the NH3-SCR reaction (wherein, vanadium pentoxide is the active component for the NH3-SCR reaction). The core active center for denitrification, with tungsten trioxide as an additive significantly enhancing surface acidity and synergistically improving denitrification activity and stability, consists of a hollow spherical titanium dioxide shell and a composite active component of chromium trioxide and cerium dioxide for the catalytic oxidation reaction of chlorinated organics. (Chromium trioxide is the core active phase for breaking C-Cl bonds and deeply oxidizing chlorinated organics, while cerium dioxide, with its excellent oxygen storage and release capacity, can provide active oxygen species for the oxidation reaction and alleviate chlorine poisoning. The two synergistically enhance the mineralization efficiency and product selectivity of chlorinated organics.) The hollow spherical titanium dioxide shell physically isolates the composite active component of vanadium pentoxide and tungsten trioxide from the composite active component of chromium trioxide and cerium dioxide (the spherical titanium dioxide shell acts as a barrier layer to effectively isolate the internal and external active sites), achieving reaction partitioning for the NH3-SCR reaction and the catalytic oxidation reaction of chlorinated organics. This avoids competitive adsorption of different reaction atmospheres and the poisoning of the NH3-SCR denitrification active component by chlorobenzene, thus exhibiting good catalytic performance and product selectivity.

[0006] Furthermore, the proportions of vanadium pentoxide, tungsten trioxide, chromium trioxide, and cerium dioxide in the catalyst are independently 1-5 wt% (the proportions of each active component may be the same or different), for example, 1 wt%, 2 wt%, 3 wt%, 4 wt%, or 5 wt%, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0007] Preferably, the proportions of vanadium pentoxide, tungsten trioxide, chromium trioxide and cerium dioxide in the catalyst are all 1-3 wt%.

[0008] Furthermore, the hollow spherical titanium dioxide shell accounts for 80-96 wt% of the catalyst, for example, 80 wt%, 84 wt%, 88 wt%, 92 wt%, or 96 wt%, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0009] The second technical solution of the present invention: a method for preparing a hollow structure catalyst for the above-mentioned reaction partitioning to remove nitrogen oxides and chlorinated organic compounds, comprising the following steps: Using vanadium precursor, tungsten precursor and carbon ball precursor as raw materials, carbon ball powder (abbreviated as VW / C) with anchored vanadium-tungsten composite active components is obtained through hydrothermal reaction. The titanium precursor is coated onto the surface of the carbon ball powder anchored to the vanadium-tungsten composite active component by means of a sol-gel method, to obtain titanium (specifically, titanium precursor) coated carbon ball powder anchored to the vanadium-tungsten composite active component (referred to as VW / C@Ti). The titanium-coated carbon ball powder with anchored vanadium-tungsten composite active components is subjected to a first calcination treatment (to remove the carbon balls) to obtain titanium ball powder with hollow structure and vanadium-tungsten composite active components loaded on the inner surface (referred to as VW@Ti). Chromium and cerium precursors were loaded onto the inner surface of titanium sphere powder loaded with vanadium-tungsten composite active components by impregnation, and then subjected to a second calcination treatment to obtain the hollow-structured catalyst (referred to as CrCe / VW@Ti) for removing nitrogen oxides and chlorinated organic compounds in the reaction zone.

[0010] This invention uses a hydrothermal method to anchor vanadium-tungsten composite active components onto carbon spheres to obtain VW / C powder. A titanium precursor is then coated onto the surface of the VW / C powder using a sol-gel method, followed by a first calcination treatment to remove the carbon spheres and generate titanium dioxide, resulting in hollow spherical VW@Ti powder. A chromium-cerium active component precursor is impregnated onto the hollow spherical VW@Ti powder, followed by a second calcination treatment to obtain a hollow catalyst CrCe / VW@Ti, with a hollow spherical titanium dioxide shell as a support (barrier layer), an outer layer of chromium-cerium composite active components, and an inner layer of vanadium-tungsten composite active components.

[0011] Furthermore, the hydrothermal reaction step includes: mixing vanadium precursor, tungsten precursor, carbon sphere precursor and water, and carrying out a hydrothermal reaction.

[0012] Furthermore, the vanadium precursor is added in the form of an aqueous vanadium precursor solution, and the tungsten precursor is added in the form of an aqueous tungsten precursor solution, that is, the aqueous vanadium precursor solution, the aqueous tungsten precursor solution, the carbon sphere precursor and water are mixed and a hydrothermal reaction is carried out.

[0013] Furthermore, the process after the hydrothermal reaction is completed includes centrifugation, washing, and drying steps.

[0014] Furthermore, the sol-gel method includes: dispersing the carbon ball powder of the anchored vanadium-tungsten composite active component in a solvent, adding a titanium precursor, stirring and reacting, and then allowing it to stand to obtain titanium-coated carbon ball powder of the anchored vanadium-tungsten composite active component.

[0015] Compared to the hydrothermal method, the sol-gel method can achieve uniform coating of titanium precursors under mild conditions, thereby achieving uniform coating and precise thickness control of the TiO2 shell. This avoids the problems of carbon sphere template collapse and vanadium-tungsten active component migration caused by the high temperature and high pressure environment of the hydrothermal method. As a result, a mesoporous TiO2 shell is obtained, which can not only ensure efficient mass transfer of small molecule reactants, but also effectively retain chlorinated organic compounds that poison intermediates.

[0016] Furthermore, the carbon ball powder anchoring the vanadium-tungsten composite active component is dispersed in a solvent by ultrasonic dispersion.

[0017] Furthermore, the settling process also includes centrifugation, washing, and drying steps.

[0018] Furthermore, the impregnation method includes the following steps: mixing chromium precursor, cerium precursor, titanium ball powder with vanadium-tungsten composite active components loaded on the inner surface of the hollow structure, and water, heating and stirring, and then drying.

[0019] Furthermore, the chromium precursor is added in the form of an aqueous solution of the chromium precursor, and the cerium precursor is added in the form of an aqueous solution of the cerium precursor. That is, the aqueous solution of the chromium precursor, the aqueous solution of the cerium precursor, the titanium ball powder with vanadium-tungsten composite active components loaded on the inner surface of the hollow structure, and water are mixed, heated and stirred, and then dried.

[0020] Preferably, the drying after heating and stirring is specifically rotary evaporation drying.

[0021] Preferably, the preparation method includes the following more specific steps: (1) Add vanadium precursor aqueous solution, tungsten precursor aqueous solution and carbon ball precursor to water and mix evenly. After hydrothermal reaction, centrifuge, wash and dry to obtain VW / C powder. (2) The VW / C powder obtained in step (1) is added to a solvent, ultrasonically dispersed, and then titanium precursor is added and stirred vigorously. After standing, it is centrifuged, washed and dried to obtain VW / C@Ti powder. (3) The VW / C@Ti powder obtained in step (2) is subjected to a first calcination treatment to remove carbon spheres and obtain hollow spherical VW@Ti powder; (4) Add the aqueous solution of chromium precursor, the aqueous solution of cerium precursor and the VW@Ti powder obtained in step (3) to water and mix evenly. After stirring in a water bath, dry by rotary evaporation and calcination for a second time to obtain the hollow structure catalyst CrCe / VW@Ti that removes nitrogen oxides and chlorinated organics in the reaction zone.

[0022] Furthermore, the vanadium precursor includes ammonium metavanadate.

[0023] Furthermore, the tungsten precursor includes ammonium metatungstate.

[0024] Furthermore, the carbon sphere precursor includes glucose.

[0025] Furthermore, the mass ratio of the vanadium precursor (i.e., the vanadium precursor contained in the vanadium precursor aqueous solution), the tungsten precursor (i.e., the tungsten precursor contained in the tungsten precursor aqueous solution) and the carbon sphere precursor is 0.04-0.2:0.0325-0.1625:6-14.

[0026] Furthermore, the concentration of the vanadium precursor aqueous solution is 0.01 g / mL.

[0027] Furthermore, the concentration of the tungsten precursor aqueous solution is 0.01 g / mL.

[0028] Further, the volume ratio of the vanadium precursor aqueous solution, the tungsten precursor aqueous solution, and the water is 4-20:3.25-16.25:100. For example, the volume ratio of the vanadium precursor aqueous solution to the water can be 4:100, 8:100, 12:100, 16:100, or 20:100, and the volume ratio of the tungsten precursor aqueous solution to the water can be 3.25:100, 6.5:100, 9.75:100, 13:100, or 16.25:100, but is not limited to the listed values; other unlisted values ​​within the range are also applicable.

[0029] Furthermore, the mass-to-volume ratio of the carbon sphere precursor to the water is 6-14 g:100 mL, for example, it can be 6 g:100 mL, 7 g:100 mL, 8 g:100 mL, 9 g:100 mL, 10 g:100 mL, 11 g:100 mL, 12 g:100 mL, 13 g:100 mL or 14 g:100 mL, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Furthermore, the temperature of the hydrothermal reaction is 120-180℃, for example, it can be 120℃, 130℃, 140℃, 150℃, 160℃, 170℃ or 180℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0031] Furthermore, the hydrothermal reaction time is 9-15 hours, for example, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours or 15 hours, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] The hydrothermal reaction serves to condense and carbonize anhydrous glucose, the precursor of carbon spheres, under high temperature and pressure. This process causes amorphous molecules to aggregate and gradually nucleate, growing directionally into spherical carbon matrices with regular morphology and stable frameworks. Furthermore, the hydrothermal reaction allows the vanadium-tungsten composite active components to be simultaneously fixed onto the surface and pores of the carbon spheres during their growth, achieving anchored loading of the active components. Excessively high hydrothermal temperatures can cause the condensation and carbonization rates of the carbon sphere precursors to be too rapid, leading to uncontrolled nucleation and growth, severe agglomeration, and uneven particle size in the carbon spheres. Conversely, excessively low hydrothermal temperatures can result in insufficient driving force for the condensation and carbonization reactions, making nucleation difficult, growth slow, and hindering the formation of regular spherical structures. Excessively long hydrothermal times can cause the carbon spheres to grow continuously, resulting in large and uneven particle sizes, with some spheres fusing and adhering, disrupting the spherical morphology. Conversely, insufficient hydrothermal times lead to incomplete condensation and carbonization of the carbon sphere precursors, resulting in incomplete spherical growth. Therefore, it is crucial to control the hydrothermal time and temperature within a reasonable range.

[0033] Preferably, the washing after the hydrothermal reaction is performed three times, the drying temperature is 80°C, and the drying time is 20 hours.

[0034] Furthermore, the titanium precursor includes tetrabutyl titanate, titanium isopropoxide, or titanium tetrachloride.

[0035] Furthermore, the solvent includes anhydrous ethanol.

[0036] Furthermore, the mass ratio of vanadium in the carbon ball powder anchoring the vanadium-tungsten composite active component to titanium in the titanium precursor is 1:17-98, for example, it can be 1:17, 1:22, 1:32.5, 1:49 or 1:98, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0037] Furthermore, the ultrasonic dispersion time is 10-50 min, for example, it can be 10 min, 20 min, 30 min, 40 min or 50 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0038] Furthermore, the temperature of the stirring reaction is 20-30℃ (i.e., room temperature), and the time is 30-90 min, for example, it can be 30 min, 40 min, 50 min, 60 min, 70 min, 80 min or 90 min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0039] The purpose of ultrasonic dispersion is to ensure that the VW / C powder is evenly dispersed in the solvent to form a uniform suspension, while the purpose of stirring is to coat the VW / C powder surface with the titanium precursor. Insufficient ultrasonic dispersion and stirring times will result in uneven coating of the titanium precursor on the VW / C powder surface; therefore, the ultrasonic dispersion and stirring times need to be controlled within a reasonable range.

[0040] Furthermore, the settling temperature is 20-30℃ (i.e., room temperature), and the time is 10-20h, for example, it can be 10h, 12h, 14h, 16h, 18h or 20h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0041] The settling period is part of the aging stage of the sol-gel method, which allows the titanium precursor to complete the coating on the surface of VW / C powder. Too short a settling time may result in insufficient coating and failure of the titanium precursor to coat the VW / C powder surface. Therefore, the settling time needs to be controlled within a reasonable range.

[0042] Preferably, the washing is performed 3 times after standing, and the drying temperature is 80℃ for 20 hours.

[0043] Furthermore, the temperature of the first calcination treatment is 400-550℃ and the time is 3-5h. For example, the temperature can be 400℃, 450℃, 500℃ or 550℃ and the time can be 3h, 4h or 5h, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0044] The purpose of the first calcination treatment is to pyrolyze the titanium precursor coated on the surface of the VW / C powder into anatase titanium dioxide, while simultaneously oxidizing the vanadium and tungsten precursors into a composite active component of vanadium pentoxide and tungsten trioxide with denitrification activity. It also removes the carbon spheres inside the catalyst, obtaining hollow spherical VW@Ti powder. Too low a calcination temperature and too short a calcination time will result in incomplete removal of the carbon sphere template, incomplete crystallization of titanium dioxide, and insufficient oxidation of the vanadium and tungsten precursors. Too high a calcination temperature and too long a calcination time will cause titanium dioxide to transform from the anatase phase to the rutile phase. Therefore, it is necessary to control the calcination time and temperature within a reasonable range.

[0045] Furthermore, the chromium precursor comprises chromium nitrate nonahydrate.

[0046] Furthermore, the cerium precursor comprises cerium nitrate hexahydrate.

[0047] Furthermore, the mass ratio of the chromium precursor (i.e., the chromium precursor contained in the aqueous solution of the chromium precursor), the cerium precursor (i.e., the cerium precursor contained in the aqueous solution of the cerium precursor), and the titanium ball powder with vanadium-tungsten composite active components loaded on the inner surface of the hollow structure is 0.055-0.29:0.025-0.14:1.

[0048] Furthermore, the concentration of the aqueous solution of the chromium precursor is 0.01 g / mL.

[0049] Furthermore, the concentration of the cerium precursor aqueous solution is 0.01 g / mL.

[0050] Furthermore, the volume ratio of the chromium precursor aqueous solution, the cerium precursor aqueous solution, and the water is 5.5-29:2.5-14:50. For example, the volume ratio of the chromium precursor aqueous solution to the water can be 5.5:50, 10:50, 15:50, 20:50, or 29:50, and the volume ratio of the cerium precursor aqueous solution to the water can be 2.5:50, 6:50, 9:50, 12:50, or 14:50, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0051] Furthermore, the mass-to-volume ratio of the titanium ball powder with vanadium-tungsten composite active components loaded on the inner surface to the aqueous solution of the chromium precursor is 1g:5.5-29mL.

[0052] Furthermore, the heating and stirring temperature is 30-60℃ and the time is 30-90min, for example, it can be 30min, 40min, 50min, 60min, 70min, 80min or 90min, but is not limited to the listed values. Other values ​​not listed within the range are also applicable.

[0053] Furthermore, the temperature of the rotary drying is 40-80℃, for example, it can be 40℃, 50℃, 60℃, 70℃ or 80℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0054] Furthermore, the temperature of the second calcination treatment is 400-550℃ and the time is 3-5h. For example, the temperature can be 400℃, 450℃, 500℃ or 550℃ and the time can be 3h, 4h or 5h, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0055] The purpose of the second calcination treatment is to oxidize the chromium and cerium precursors impregnated on the surface of the hollow spherical VW@Ti powder into a composite active component of chromium trioxide and cerium dioxide with chlorinated organic oxidizing activity. Too low a calcination temperature and too short a calcination time will result in insufficient oxidation of the chromium and cerium precursors; too high a calcination temperature and too long a calcination time will cause titanium dioxide to transform from the anatase phase to the rutile phase. Therefore, it is necessary to control the calcination time and temperature within a reasonable range.

[0056] The third technical solution of the present invention: the application of a hollow structure catalyst for removing nitrogen oxides and chlorinated organic compounds in the above-mentioned reaction partition in the synergistic removal of nitrogen oxides and chlorinated organic compounds in flue gas.

[0057] In the synergistic removal of nitrogen oxides and chlorinated organic compounds, nitrogen oxides are removed via the NH3-SCR reaction, while chlorinated organic compounds are removed via catalytic oxidation.

[0058] Furthermore, the nitrogen oxides include NO, and the chlorinated organic compounds include chlorobenzene.

[0059] Furthermore, the temperature for the synergistic removal is 150-400℃, for example, it can be 150℃, 200℃, 250℃, 300℃, 350℃ or 400℃, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0060] The hollow-structured catalyst for the removal of nitrogen oxides and chlorinated organic compounds provided by this invention uses a hollow spherical titanium dioxide shell as a support. The outer layer is loaded with a composite active component of chromium trioxide and cerium dioxide, while the inner layer is loaded with a composite active component of vanadium pentoxide and tungsten trioxide. Compared with traditional catalysts for the removal of nitrogen oxides and chlorinated organic compounds, the catalyst prepared by this invention isolates the NH3-SCR active component and the chlorinated organic compound catalytic oxidation active component through the hollow spherical titanium dioxide shell. This partitions the NH3-SCR and chlorinated organic compound catalytic oxidation reactions, avoiding competitive adsorption between active sites of different atmospheres, thereby exhibiting good catalytic performance and product selectivity.

[0061] The hollow-structure catalyst for the reaction partitioning removal of nitrogen oxides and chlorinated organic compounds provided by this invention can achieve efficient removal of nitrogen oxides and chlorinated organic compounds simultaneously at low temperatures.

[0062] The present invention discloses the following technical effects: (1) The hollow structure catalyst for removing nitrogen oxides and chlorinated organics provided by the present invention consists of, from the inside out, a composite active component of vanadium pentoxide and tungsten trioxide for NH3-SCR denitrification, a hollow spherical titanium dioxide shell, and a composite active component of chromium trioxide and cerium dioxide for catalytic oxidation of chlorinated organics. The hollow spherical titanium dioxide shell of the catalyst effectively isolates the internal and external active sites, thereby realizing the reaction partitioning of NH3-SCR reaction and catalytic oxidation of chlorinated organics. This avoids competitive adsorption of different reaction atmospheres and poisoning of the NH3-SCR denitrification active component by chlorinated organics, significantly improving the removal efficiency of nitrogen oxides and chlorinated organics, and greatly reducing the generation of peroxidation byproducts in the reaction. It has good application prospects in the field of multi-pollutant treatment of industrial flue gas.

[0063] (2) This invention combines hydrothermal method, sol-gel method and impregnation method to prepare a reaction partition dual-effect catalyst with hollow structure externally supported chromium and cerium and internally supported vanadium and tungsten. The prepared catalyst is used for the removal of chlorinated organics and nitrogen oxides and has good catalytic performance and product selectivity. Attached Figure Description

[0064] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0065] Figure 1 The image shows a SEM image of the hollow catalyst CrCe / VW@Ti prepared in Example 1 for the reaction partitioning removal of nitrogen oxides and chlorinated organic compounds.

[0066] Figure 2 The XRD patterns are of the hollow-structured catalysts CrCe / VW@Ti prepared in Examples 1-5 for the reaction partitioning removal of nitrogen oxides and chlorinated organic compounds. Detailed Implementation

[0067] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0068] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0069] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0070] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0071] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0072] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0073] Unless otherwise specified, the room temperature mentioned in the following embodiments, comparative examples and test examples of this invention refers to 20-30°C.

[0074] Unless otherwise specified, all raw materials used in the following embodiments, comparative examples and test examples of this invention are commercially available products.

[0075] Example 1 This embodiment provides a hollow core-shell catalyst for the reaction partitioning removal of nitrogen oxides and chlorinated organic compounds. It consists of a hollow spherical titanium dioxide shell (i.e., a hollow spherical titanium dioxide shell), a composite active component of vanadium pentoxide and tungsten trioxide supported on the inner surface of the hollow spherical titanium dioxide shell, and a composite active component of chromium trioxide and cerium dioxide supported on the outer surface of the hollow spherical titanium dioxide shell. The proportions of vanadium pentoxide, tungsten trioxide, chromium trioxide, cerium dioxide, and titanium dioxide shell in the catalyst (specifically referring to the theoretical proportions, i.e., calculated based on the mass of oxides that can be generated corresponding to the titanium, vanadium, tungsten, chromium, and cerium elements contained in the raw materials) are approximately 2wt%, 2wt%, 2wt%, 2wt%, and 92wt%, respectively (rounded to the nearest integer in the calculation).

[0076] The preparation method of the hollow-structured catalyst for the removal of nitrogen oxides and chlorinated organic compounds in the above reaction zone is as follows: (1) Add 0.01 g / mL of ammonium metavanadate aqueous solution, 0.01 g / mL of ammonium metatungstate aqueous solution and anhydrous glucose to deionized water and mix evenly (the volume ratio of ammonium metavanadate aqueous solution, ammonium metatungstate aqueous solution and deionized water is 8:6.5:100, and the mass-volume ratio of anhydrous glucose and deionized water is 9 g:100 mL). After hydrothermal reaction at 180℃ for 10 h, centrifuge, wash 3 times, and dry at 80℃ for 20 h to obtain VW / C powder; (2) Add the VW / C powder obtained in step (1) to anhydrous ethanol (the mass-volume ratio of VW / C powder to anhydrous ethanol is 1g:30mL), ultrasonically disperse for 30min, then add tetrabutyl titanate (the mass ratio of V element in VW / C powder to Ti element in tetrabutyl titanate is 1:49), stir vigorously at room temperature for 60min (speed is 70r / min), let stand at room temperature for 18h, centrifuge, wash 3 times, dry at 80℃ for 20h to obtain VW / C@Ti powder; (3) The VW / C@Ti powder obtained in step (2) is subjected to a first calcination treatment, specifically calcined at 500℃ for 4h to remove carbon spheres and obtain hollow spherical VW@Ti powder; (4) Add 0.01 g / mL chromium nitrate nonahydrate aqueous solution, 0.01 g / mL cerium nitrate hexahydrate aqueous solution and VW@Ti powder obtained in step (3) to deionized water and mix evenly (the volume ratio of chromium nitrate aqueous solution, cerium nitrate hexahydrate aqueous solution and deionized water is 11:5:50, and the mass-volume ratio of VW@Ti powder and chromium nitrate nonahydrate aqueous solution is 1 g:11 mL). After stirring in a water bath at 50℃ for 60 min, dry by rotary evaporation at 60℃ for 2 h and calcinate at 500℃ for 4 h to obtain the hollow structure catalyst CrCe / VW@Ti for removing nitrogen oxides and chlorinated organics in the reaction zone.

[0077] Example 2 This embodiment provides a hollow structure catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones. It consists of a hollow spherical titanium dioxide shell, a composite active component of vanadium pentoxide and tungsten trioxide supported on the inner surface of the hollow spherical titanium dioxide shell, and a composite active component of chromium trioxide and cerium dioxide supported on the outer surface of the hollow spherical titanium dioxide shell. The proportions of vanadium pentoxide, tungsten trioxide, chromium trioxide, cerium dioxide, and titanium dioxide shell in the catalyst are approximately 1 wt%, 1 wt%, 1 wt%, 1 wt%, and 96 wt%, respectively.

[0078] The preparation method of the hollow-structured catalyst for the removal of nitrogen oxides and chlorinated organic compounds in the above reaction zone is as follows: (1) Add 0.01 g / mL of ammonium metavanadate aqueous solution, 0.01 g / mL of ammonium metatungstate aqueous solution and anhydrous glucose to deionized water and mix evenly (the volume ratio of ammonium metavanadate aqueous solution, ammonium metatungstate aqueous solution and deionized water is 4:3.25:100, and the mass-volume ratio of anhydrous glucose and deionized water is 9 g:100 mL). After hydrothermal reaction at 180℃ for 10 h, centrifuge, wash 3 times, and dry at 80℃ for 20 h to obtain VW / C powder; (2) The VW / C powder obtained in step (1) was added to anhydrous ethanol (the mass-volume ratio of VW / C powder to anhydrous ethanol was 1 g: 30 mL), ultrasonically dispersed for 30 min, and then tetrabutyl titanate was added (the mass ratio of V element in VW / C powder to Ti element in tetrabutyl titanate was 1: 98). The mixture was stirred vigorously at room temperature for 60 min (rotation speed was 70 r / min), and then allowed to stand at room temperature for 18 h. After centrifugation, washing 3 times, and drying at 80 °C for 20 h, VW / C@Ti powder was obtained. (3) The VW / C@Ti powder obtained in step (2) is subjected to a first calcination treatment, specifically calcined at 500℃ for 4h to remove carbon spheres and obtain hollow spherical VW@Ti powder; (4) Add 0.01 g / mL chromium nitrate nonahydrate aqueous solution, 0.01 g / mL cerium nitrate hexahydrate aqueous solution and VW@Ti powder obtained in step (3) to deionized water and mix evenly (the volume ratio of chromium nitrate aqueous solution, cerium nitrate hexahydrate aqueous solution and deionized water is 5.5:2.5:50, and the mass-volume ratio of VW@Ti powder and chromium nitrate nonahydrate aqueous solution is 1 g:5.5 mL). After stirring in a water bath at 50℃ for 60 min, dry by rotary evaporation at 60℃ for 2 h and calcinate at 500℃ for 4 h to obtain the hollow structure catalyst CrCe / VW@Ti for removing nitrogen oxides and chlorinated organics in the reaction zone.

[0079] Example 3 This embodiment provides a hollow-structured catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones. It consists of a hollow spherical titanium dioxide shell, a composite active component of vanadium pentoxide and tungsten trioxide supported on the inner surface of the hollow spherical titanium dioxide shell, and a composite active component of chromium trioxide and cerium dioxide supported on the outer surface of the hollow spherical titanium dioxide shell. The proportions of vanadium pentoxide, tungsten trioxide, chromium trioxide, cerium dioxide, and titanium dioxide shell in the catalyst are approximately 3 wt%, 3 wt%, 3 wt%, 3 wt%, and 88 wt%, respectively.

[0080] The preparation method of the hollow-structured catalyst for the removal of nitrogen oxides and chlorinated organic compounds in the above reaction zone is as follows: (1) Add 0.01 g / mL of ammonium metavanadate aqueous solution, 0.01 g / mL of ammonium metatungstate aqueous solution and anhydrous glucose to deionized water and mix evenly (the volume ratio of ammonium metavanadate aqueous solution, ammonium metatungstate aqueous solution and deionized water is 12:10:100, and the mass-volume ratio of anhydrous glucose and deionized water is 9 g:100 mL). After hydrothermal reaction at 180℃ for 10 h, centrifuge, wash 3 times, and dry at 80℃ for 20 h to obtain VW / C powder. (2) The VW / C powder obtained in step (1) was added to anhydrous ethanol (the mass-volume ratio of VW / C powder to anhydrous ethanol was 1 g: 30 mL), ultrasonically dispersed for 30 min, and then tetrabutyl titanate was added (the mass ratio of V element in VW / C powder to Ti element in tetrabutyl titanate was 1: 32.5). The mixture was stirred vigorously at room temperature for 60 min (speed was 70 r / min), and then allowed to stand at room temperature for 18 h. After centrifugation, washing 3 times, and drying at 80 °C for 20 h, VW / C@Ti powder was obtained. (3) The VW / C@Ti powder obtained in step (2) is subjected to a first calcination treatment, specifically calcined at 500℃ for 4h to remove carbon spheres and obtain hollow spherical VW@Ti powder; (4) Add 0.01 g / mL chromium nitrate nonahydrate aqueous solution, 0.01 g / mL cerium nitrate hexahydrate aqueous solution and VW@Ti powder obtained in step (3) to deionized water and mix evenly (the volume ratio of chromium nitrate aqueous solution, cerium nitrate hexahydrate aqueous solution and deionized water is 16.5:8:50, and the mass-volume ratio of VW@Ti powder and chromium nitrate nonahydrate aqueous solution is 1 g:16.5 mL). After stirring in a water bath at 50 °C for 60 min, dry by rotary evaporation at 60 °C for 2 h and calcinate at 500 °C for 4 h to obtain the hollow structure catalyst CrCe / VW@Ti for removing nitrogen oxides and chlorinated organics in the reaction zone.

[0081] Example 4 This embodiment provides a hollow structure catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones. It consists of a hollow spherical titanium dioxide shell, a composite active component of vanadium pentoxide and tungsten trioxide supported on the inner surface of the hollow spherical titanium dioxide shell, and a composite active component of chromium trioxide and cerium dioxide supported on the outer surface of the hollow spherical titanium dioxide shell. The proportions of vanadium pentoxide, tungsten trioxide, chromium trioxide, cerium dioxide, and titanium dioxide shell in the catalyst are approximately 4 wt%, 4 wt%, 4 wt%, 4 wt%, and 84 wt%, respectively.

[0082] The preparation method of the hollow-structured catalyst for the removal of nitrogen oxides and chlorinated organic compounds in the above reaction zone is as follows: (1) Add 0.01 g / mL of ammonium metavanadate aqueous solution, 0.01 g / mL of ammonium metatungstate aqueous solution and anhydrous glucose to deionized water and mix evenly (the volume ratio of ammonium metavanadate aqueous solution, ammonium metatungstate aqueous solution and deionized water is 16:13:100, and the mass-volume ratio of anhydrous glucose and deionized water is 9 g:100 mL). After hydrothermal reaction at 180℃ for 10 h, centrifuge, wash 3 times, and dry at 80℃ for 20 h to obtain VW / C powder; (2) Add the VW / C powder obtained in step (1) to anhydrous ethanol (the mass-volume ratio of VW / C powder to anhydrous ethanol is 1g:30mL), ultrasonically disperse for 30min, then add tetrabutyl titanate (the mass ratio of V element in VW / C powder to Ti element in tetrabutyl titanate is 1:22), stir vigorously at room temperature for 60min (speed is 70r / min), let stand at room temperature for 18h, centrifuge, wash 3 times, dry at 80℃ for 20h to obtain VW / C@Ti powder; (3) The VW / C@Ti powder obtained in step (2) is subjected to a first calcination treatment, specifically calcined at 500℃ for 4h to remove carbon spheres and obtain hollow spherical VW@Ti powder; (4) Add 0.01 g / mL chromium nitrate nonahydrate aqueous solution, 0.01 g / mL cerium nitrate hexahydrate aqueous solution and VW@Ti powder obtained in step (3) to deionized water and mix evenly (the volume ratio of chromium nitrate aqueous solution, cerium nitrate hexahydrate aqueous solution and deionized water is 23:11:50, and the mass-volume ratio of VW@Ti powder and chromium nitrate nonahydrate aqueous solution is 1 g:23 mL). After stirring in a water bath at 50℃ for 60 min, dry by rotary evaporation at 60℃ for 2 h and calcinate at 500℃ for 4 h to obtain the hollow structure catalyst CrCe / VW@Ti for removing nitrogen oxides and chlorinated organics in the reaction zone.

[0083] Example 5 This embodiment provides a hollow structure catalyst for the reaction partitioning removal of nitrogen oxides and chlorinated organic compounds. It consists of a hollow spherical titanium dioxide shell, a composite active component of vanadium pentoxide and tungsten trioxide supported on the inner surface of the hollow spherical titanium dioxide shell, and a composite active component of chromium trioxide and cerium dioxide supported on the outer surface of the hollow spherical titanium dioxide shell. The proportions of vanadium pentoxide, tungsten trioxide, chromium trioxide, cerium dioxide, and titanium dioxide shell in the catalyst are approximately 5 wt%, 5 wt%, 5 wt%, 5 wt%, and 80 wt%, respectively.

[0084] The preparation method of the hollow-structured catalyst for the removal of nitrogen oxides and chlorinated organic compounds in the above reaction zone is as follows: (1) Add 0.01 g / mL of ammonium metavanadate aqueous solution, 0.01 g / mL of ammonium metatungstate aqueous solution and anhydrous glucose to deionized water and mix evenly (the volume ratio of ammonium metavanadate aqueous solution, ammonium metatungstate aqueous solution and deionized water is 20:16.25:100, and the mass-volume ratio of anhydrous glucose and deionized water is 9 g:100 mL). After hydrothermal reaction at 180℃ for 10 h, centrifuge, wash 3 times, and dry at 80℃ for 20 h to obtain VW / C powder; (2) The VW / C powder obtained in step (1) was added to anhydrous ethanol (the mass-volume ratio of VW / C powder to anhydrous ethanol was 1 g: 30 mL), ultrasonically dispersed for 30 min, and then tetrabutyl titanate was added (the mass ratio of V element in VW / C powder to Ti element in tetrabutyl titanate was 1:17). The mixture was stirred vigorously at room temperature for 60 min (rotation speed was 70 r / min), and then allowed to stand at room temperature for 18 h. After centrifugation, washing 3 times, and drying at 80 °C for 20 h, VW / C@Ti powder was obtained. (3) The VW / C@Ti powder obtained in step (2) is subjected to a first calcination treatment, specifically calcined at 500℃ for 4h to remove carbon spheres and obtain hollow spherical VW@Ti powder; (4) Add 0.01 g / mL chromium nitrate nonahydrate aqueous solution, 0.01 g / mL cerium nitrate hexahydrate aqueous solution and VW@Ti powder obtained in step (3) to deionized water and mix evenly (the volume ratio of chromium nitrate aqueous solution, cerium nitrate hexahydrate aqueous solution and deionized water is 29:14:50, and the mass-volume ratio of VW@Ti powder and chromium nitrate nonahydrate aqueous solution is 1 g:29 mL). After stirring in a water bath at 50°C for 60 min, dry by rotary evaporation at 60°C for 2 h and calcinate at 500°C for 4 h to obtain the hollow structure catalyst CrCe / VW@Ti for removing nitrogen oxides and chlorinated organics in the reaction zone.

[0085] Comparative Example 1 This comparative example provides a catalyst composed of a hollow spherical titanium dioxide shell and a composite active component of chromium trioxide and cerium dioxide supported on the outer surface of the hollow spherical titanium dioxide shell; the yield ratios of chromium trioxide, cerium dioxide and titanium dioxide shell in the catalyst are approximately 2 wt%, 2 wt% and 96 wt%, respectively.

[0086] The preparation method of the above catalyst is as follows: (1) Add anhydrous glucose to deionized water and mix evenly (the mass-volume ratio of anhydrous glucose to deionized water is 9g:100mL). After hydrothermal reaction at 180℃ for 10h, centrifuge, wash 3 times, and dry at 80℃ for 20h to obtain carbon ball powder. (2) The carbon ball powder obtained in step (1) was added to anhydrous ethanol (the mass-volume ratio of carbon ball powder to anhydrous ethanol was 1 g: 30 mL), ultrasonically dispersed for 30 min, and then tetrabutyl titanate (the mass ratio of carbon ball powder to tetrabutyl titanate was 1: 2.4) was added. The mixture was stirred vigorously at room temperature for 60 min (rotation speed was 70 r / min), and then allowed to stand at room temperature for 18 h. After centrifugation, washing 3 times, and drying at 80 °C for 20 h, C@Ti powder was obtained. (3) The C@Ti powder obtained in step (2) is subjected to a first calcination treatment, specifically calcined at 500℃ for 4h to remove carbon spheres and obtain hollow spherical TiO2 powder; (4) Add 0.01 g / mL chromium nitrate nonahydrate aqueous solution, 0.01 g / mL cerium nitrate hexahydrate aqueous solution and TiO2 powder obtained in step (3) to deionized water and mix evenly (the volume ratio of chromium nitrate aqueous solution, cerium nitrate hexahydrate aqueous solution and deionized water is 11:5:50, and the mass-volume ratio of TiO2 powder and chromium nitrate nonahydrate aqueous solution is 1 g:11 mL). After stirring in a water bath at 50℃ for 60 min, dry by rotary evaporation at 60℃ for 2 h and calcinate at 500℃ for 4 h to obtain hollow structure catalyst CrCe@Ti.

[0087] Comparative Example 2 This comparative example provides a catalyst composed of a hollow spherical titanium dioxide shell and a composite active component of vanadium pentoxide and tungsten trioxide supported on the inner surface of the hollow spherical titanium dioxide shell; the proportions of vanadium pentoxide, tungsten trioxide and titanium dioxide shell in the catalyst are approximately 2 wt%, 2 wt% and 96 wt%, respectively.

[0088] The preparation method of the above catalyst is as follows: (1) Add 0.01 g / mL of ammonium metavanadate aqueous solution, 0.01 g / mL of ammonium metatungstate aqueous solution and anhydrous glucose to deionized water and mix evenly (the volume ratio of ammonium metavanadate aqueous solution, ammonium metatungstate aqueous solution and deionized water is 8:6.5:100, and the mass-volume ratio of anhydrous glucose and deionized water is 9 g:100 mL). After hydrothermal reaction at 180℃ for 10 h, centrifuge, wash 3 times, and dry at 80℃ for 20 h to obtain VW / C powder; (2) Add the VW / C powder obtained in step (1) to anhydrous ethanol (the mass-volume ratio of VW / C powder to anhydrous ethanol is 1g:30mL), ultrasonically disperse for 30min, then add tetrabutyl titanate (the mass ratio of V element in VW / C powder to Ti element in tetrabutyl titanate is 1:49), stir vigorously at room temperature for 60min (speed is 70r / min), let stand at room temperature for 18h, centrifuge, wash 3 times, dry at 80℃ for 20h to obtain VW / C@Ti powder; (3) The VW / C@Ti powder obtained in step (2) is subjected to a first calcination treatment, specifically calcined at 500°C for 4 hours to remove carbon spheres and obtain hollow spherical VW@Ti powder, which is the catalyst of this comparative example.

[0089] Comparative Example 3 This comparative example provides a catalyst comprising a hollow spherical titanium dioxide shell, a composite active component of vanadium pentoxide and tungsten trioxide supported on the outer surface of the hollow spherical titanium dioxide shell, and a composite active component of chromium trioxide and cerium dioxide; the proportions of vanadium pentoxide, tungsten trioxide, chromium trioxide, cerium dioxide, and titanium dioxide shell in the catalyst are approximately 2 wt%, 2 wt%, 2 wt%, 2 wt%, and 92 wt%, respectively.

[0090] The preparation method of the above catalyst is as follows: (1) Add anhydrous glucose to deionized water and mix evenly (the mass-volume ratio of anhydrous glucose to deionized water is 9g:100mL). After hydrothermal reaction at 180℃ for 10h, centrifuge, wash 3 times, and dry at 80℃ for 20h to obtain carbon ball powder. (2) The carbon ball powder obtained in step (1) was added to anhydrous ethanol (the mass-volume ratio of carbon ball powder to anhydrous ethanol was 1 g: 30 mL), ultrasonically dispersed for 30 min, and then tetrabutyl titanate (the mass-volume ratio of carbon ball powder to tetrabutyl titanate was 1: 2.4) was added. The mixture was stirred vigorously at room temperature for 60 min (rotation speed was 70 r / min), and then allowed to stand at room temperature for 18 h. After centrifugation, washing 3 times, and drying at 80 °C for 20 h, C@Ti powder was obtained. (3) The C@Ti powder obtained in step (2) is subjected to a first calcination treatment, specifically calcined at 500℃ for 4h to remove carbon spheres and obtain hollow spherical TiO2 powder; (4) Add 0.01 g / mL of ammonium metavanadate aqueous solution, 0.01 g / mL of ammonium metatungstate aqueous solution, 0.01 g / mL of chromium nitrate nonahydrate aqueous solution, 0.01 g / mL of cerium nitrate hexahydrate aqueous solution and TiO2 powder obtained in step (3) to deionized water and mix evenly (the volume ratio of ammonium metavanadate aqueous solution, ammonium metatungstate aqueous solution, chromium nitrate aqueous solution, cerium nitrate hexahydrate aqueous solution to deionized water is 2.8:2.3:11.4:5.5:50, and the mass-volume ratio of TiO2 powder to chromium nitrate aqueous solution is 1 g:11.4 mL). After stirring in a water bath at 50 °C for 60 min, dry by rotary evaporation at 60 °C for 2 h and calcinate at 500 °C for 4 h to obtain the hollow structure catalyst CrCeVW@Ti.

[0091] Comparative Example 4 This comparative example provides a catalyst comprising a hollow spherical titanium dioxide shell, a composite active component of vanadium pentoxide and tungsten trioxide supported on the outer surface of the hollow spherical titanium dioxide shell, and a composite active component of chromium trioxide and cerium dioxide supported on the inner surface of the hollow spherical titanium dioxide shell; the proportions of vanadium pentoxide, tungsten trioxide, chromium trioxide, cerium dioxide, and titanium dioxide shell in the catalyst are approximately 2 wt%, 2 wt%, 2 wt%, 2 wt%, and 92 wt%, respectively.

[0092] The preparation method of the above catalyst is as follows: (1) Add 0.01 g / mL of chromium nitrate nonahydrate aqueous solution, 0.01 g / mL of cerium nitrate hexahydrate aqueous solution and anhydrous glucose to deionized water and mix evenly (the volume ratio of chromium nitrate nonahydrate aqueous solution, cerium nitrate hexahydrate aqueous solution and deionized water is 10.5:5:50, and the mass-volume ratio of anhydrous glucose and deionized water is 9 g:50 mL). After hydrothermal reaction at 180℃ for 10 h, centrifuge, wash 3 times, and dry at 80℃ for 20 h to obtain CrCe / C powder; (2) The CrCe / C powder obtained in step (1) was added to anhydrous ethanol (the mass-volume ratio of CrCe / C powder to anhydrous ethanol was 1 g: 30 mL), ultrasonically dispersed for 30 min, and then tetrabutyl titanate was added (the mass ratio of Cr element in CrCe / C powder to Ti element in tetrabutyl titanate was 1:40). The mixture was stirred vigorously at room temperature for 60 min (rotation speed was 70 r / min), and then allowed to stand at room temperature for 18 h. After centrifugation, washing 3 times, and drying at 80 °C for 20 h, CrCe / C@Ti powder was obtained. (3) The CrCe / C@Ti powder obtained in step (2) is subjected to a first calcination treatment, specifically calcined at 500℃ for 4h to remove carbon spheres and obtain hollow spherical CrCe@Ti powder; (4) Add 0.01 g / mL ammonium metavanadate aqueous solution, 0.01 g / mL ammonium metatungstate aqueous solution and CrCe@Ti powder obtained in step (3) to deionized water and mix evenly (the volume ratio of ammonium metavanadate aqueous solution, ammonium metatungstate aqueous solution and deionized water is 2.7:2.2:100, and the mass-volume ratio of CrCe@Ti powder and ammonium metavanadate aqueous solution is 1 g:2.7 mL). After stirring in a water bath at 50 °C for 60 min, dry by rotary evaporation at 60 °C for 2 h and calcinate at 500 °C for 4 h to obtain hollow structure catalyst VW / CrCe@Ti.

[0093] Comparative Example 5 This comparative example provides a catalyst that differs from Example 1 in that the hydrothermal reaction conditions in step (1) of the preparation method are changed to hydrothermal reaction at 200°C for 16 hours, the conditions for the first calcination treatment in step (3) are changed to calcination at 600°C for 6 hours, and the conditions for the second calcination treatment in step (4) are changed to calcination at 600°C for 6 hours. All other conditions are the same as in Example 1.

[0094] Comparative Example 6 This comparative example provides a catalyst that differs from Example 1 in that the hydrothermal reaction conditions in step (1) of the preparation method are changed to hydrothermal reaction at 100°C for 8 hours, the conditions for the first calcination treatment in step (3) are changed to calcination at 300°C for 2 hours, and the conditions for the second calcination treatment in step (4) are changed to calcination at 300°C for 2 hours. The rest are the same as in Example 1.

[0095] Comparative Example 7 This comparative example provides a catalyst that differs from Example 1 in that the ultrasonic dispersion time in step (2) of the preparation method is changed to 10 min, the time for vigorous stirring after adding tetrabutyl titanate is changed to 20 min, and the time for standing at room temperature is changed to 8 h. The rest are the same as in Example 1.

[0096] Test Example 1 Characterization data: The SEM image of the hollow-structured catalyst CrCe / VW@Ti prepared in Example 1 for the reaction partitioning removal of nitrogen oxides and chlorinated organic compounds is shown below. Figure 1 As shown, the hollow-structured catalyst for the partial removal of nitrogen oxides and chlorinated organic compounds prepared in Example 1 exhibits a uniform and regular hollow spherical morphology. The morphologies of the hollow-structured catalysts CrCe / VW@Ti for the partial removal of nitrogen oxides and chlorinated organic compounds prepared in Examples 2-5 are similar to those in Example 1 and will not be repeated.

[0097] The XRD patterns of the hollow-structured catalyst CrCe / VW@Ti prepared in Examples 1-5 for the reaction partitioning removal of nitrogen oxides and chlorinated organic compounds are shown below. Figure 2 As shown, it can be seen that the spherical titanium dioxide shell support in the hollow structure catalysts for the removal of nitrogen oxides and chlorinated organic compounds in the reaction partitions prepared in Examples 1-5 has anatase phase as its crystal phase. The active components, vanadium pentoxide, tungsten trioxide, chromium trioxide and cerium dioxide, are not shown in the XRD pattern due to their high dispersion and low content.

[0098] Test Example 2 The catalytic performance of the catalysts prepared in Examples 1-5 and Comparative Examples 1-7 was tested under the following conditions: flue gas composition: [NO] = 200 ppm, [NH3] = 200 ppm, [C6H5Cl] = 100 ppm, [O2] = 16 vol%, N2 as carrier gas; catalyst dosage: 100 mg; reactor temperature: 150-400 °C; flue gas flow rate: 100 mL / min. The maximum NO conversion rate and the reaction temperature at which the maximum conversion rate was reached for the SCR reaction are shown in Table 1. The maximum chlorobenzene conversion rate and the reaction temperature at which the maximum conversion rate was reached for the oxidation of chlorobenzene (C6H5Cl) are shown in Table 2.

[0099] Table 1 Table 2 As can be seen from Tables 1 and 2, the hollow structure catalyst for the removal of nitrogen oxides and chlorinated organic compounds by reaction partitioning provided by the present invention has excellent NH3-SCR activity and chlorobenzene catalytic oxidation activity. It can achieve complete removal of NO at 210-250℃ (the temperature corresponding to different active component loadings is different), and the removal efficiency of chlorobenzene also reaches 100% at 280-320℃.

[0100] As can be seen from the comparison between Example 1 and Examples 2 and 5, too low an active component loading will reduce the activity of the catalyst, while too high an active component loading will improve the catalytic activity to a certain extent, but will increase the production of by-products in the reaction.

[0101] A comparison between Example 1 and Comparative Example 1 shows that the chromium-cerium active component, due to the presence of Ce... 4+ / Ce 3+The redox pair exhibited some NH3-SCR activity, but only 50% activity with an N2 selectivity of 40.5%. Furthermore, the extremely low N2 selectivity indicates that the 50% NO consumption included the formation of peroxide byproducts under the oxidation of the chromium-cerium component, and did not follow the NH3-SCR reaction pathway to produce non-toxic and harmless N2. Therefore, vanadium-tungsten was used as the main NH3-SCR active component to regulate the ability of the dual-effect catalyst to reduce NO to N2. A comparison between Example 1 and Comparative Example 2 shows that chromium and cerium are the main active components for the chlorobenzene (i.e., chlorinated organic compounds) catalytic oxidation of the catalyst. The absence of chromium and cerium significantly reduced the chlorobenzene oxidation activity of the catalyst. Although the vanadium-tungsten active component has some chlorobenzene oxidation ability, significant competitive adsorption occurred at the vanadium-tungsten active sites when both NH3 and chlorobenzene atmospheres were introduced simultaneously. This led to a decrease in catalyst selectivity and an increase in the complete chlorobenzene conversion temperature. Therefore, it is necessary to add chromium and cerium active components to regulate the catalyst's oxidation performance. A comparison of Example 1 and Comparative Example 3 shows that when the vanadium-tungsten and chromium-cerium active components are simultaneously located outside the catalyst (i.e., supported on the outer surface of the hollow spherical titanium dioxide shell), the N2 selectivity and HCl selectivity of the catalyst are significantly reduced. This is because different reactants compete for adsorption between active sites. The titanium dioxide shell effectively avoids competitive adsorption by isolating the NH3-SCR active site and the chlorobenzene catalytic oxidation site, thereby improving the product selectivity of the catalyst. A comparison of Example 1 and Comparative Example 4 shows that swapping the loading positions of the NH3-SCR active component and the chlorobenzene (i.e., chlorinated organic compound) catalytic oxidation active component significantly affects the synergistic activity of the catalyst. A comparison of Example 1 and Comparative Example 5 shows that... The comparison with Comparative Example 6 shows that if the hydrothermal reaction temperature and the first and second calcination treatments are too low or the time is too short, the active component cannot be generated. If the temperature is too high, the titanium dioxide will transform from the anatase phase to the rutile phase, reducing the catalytic activity. The comparison between Example 1 and Comparative Example 7 shows that if the stirring time at room temperature after adding the titanium precursor is too short, the amount of coated titanium precursor will decrease, which will lead to a decrease in the titanium dioxide content in the catalyst. The decrease in titanium dioxide content will cause a decrease in catalyst activity. This may be because a lower titanium dioxide content will lead to uneven coating, thereby destroying the special structure of the catalyst reaction zone. In addition, a low titanium dioxide content will lead to a decrease in the number of acidic sites on the catalyst surface, thereby inhibiting the catalyst activity.

[0102] In summary, this invention can combine hydrothermal method, sol-gel method and impregnation method to prepare a hollow structure catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones. The prepared hollow structure catalyst has good catalytic performance and product selectivity for the removal of chlorinated organic compounds and nitrogen oxides.

[0103] Specifically, the hollow-structured catalyst for the reaction partitioning removal of nitrogen oxides and chlorinated organic compounds provided by this invention consists, from the inside out, a composite active component of vanadium pentoxide and tungsten trioxide for NH3-SCR denitrification, a hollow spherical titanium dioxide shell, and a composite active component of chromium trioxide and cerium dioxide for catalytic oxidation of chlorinated organic compounds. The hollow spherical titanium dioxide shell of the catalyst effectively isolates the internal and external active sites, thereby achieving reaction partitioning between the NH3-SCR denitrification reaction and the catalytic oxidation reaction of chlorinated organic compounds. This effectively avoids the competitive adsorption problem between different reaction atmospheres and prevents chlorinated organic compounds from poisoning the NH3-SCR denitrification active component. It not only significantly improves the removal efficiency of nitrogen oxides and chlorinated organic compounds but also greatly reduces the generation of peroxidation byproducts during the reaction.

[0104] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A hollow-structured catalyst for the reaction partitioning removal of nitrogen oxides and chlorinated organic compounds, characterized in that, The catalyst has a hollow core-shell structure, including a hollow spherical titanium dioxide shell, a composite active component of vanadium pentoxide and tungsten trioxide supported on the inner surface of the hollow spherical titanium dioxide shell, and a composite active component of chromium trioxide and cerium dioxide supported on the outer surface of the hollow spherical titanium dioxide shell. The preparation steps of the hollow-structured catalyst for removing nitrogen oxides and chlorinated organic compounds in the reaction zone include: Carbon ball powder anchored with vanadium-tungsten composite active components was obtained by hydrothermal reaction using vanadium precursor, tungsten precursor and carbon ball precursor as raw materials. Titanium precursors were coated onto the surface of carbon ball powder anchored to vanadium-tungsten composite active components using a sol-gel method to obtain titanium-coated carbon ball powder anchored to vanadium-tungsten composite active components. The titanium-coated carbon ball powder with anchored vanadium-tungsten composite active components was subjected to a first calcination treatment to obtain titanium ball powder with hollow structure and vanadium-tungsten composite active components loaded on the inner surface. Chromium and cerium precursors were loaded onto the inner surface of titanium sphere powder loaded with vanadium-tungsten composite active components by impregnation, and then subjected to a second calcination treatment to obtain the hollow structure catalyst for removing nitrogen oxides and chlorinated organic compounds in the reaction zone. The hydrothermal reaction steps include: mixing vanadium precursor, tungsten precursor, carbon sphere precursor and water, and carrying out a hydrothermal reaction.

2. The hollow-structure catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones as described in claim 1, characterized in that, The proportions of vanadium pentoxide, tungsten trioxide, chromium trioxide and cerium dioxide in the catalyst are independently 1-5 wt%; the proportion of the hollow spherical titanium dioxide shell in the catalyst is 80-96 wt%.

3. The hollow-structure catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones as described in claim 1, characterized in that, The vanadium precursor includes ammonium metavanadate; And / or, the tungsten precursor includes ammonium metatungstate; And / or, the carbon sphere precursor includes glucose.

4. The hollow-structure catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones as described in claim 3, characterized in that, The mass ratio of the vanadium precursor, the tungsten precursor, and the carbon sphere precursor is 0.04-0.2:0.0325-0.1625:6-14; And / or, the hydrothermal reaction is carried out at a temperature of 120-180°C for a time of 9-15 hours.

5. The hollow-structure catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones as described in claim 1, characterized in that, The steps of the sol-gel method include: dispersing the carbon ball powder of the anchored vanadium-tungsten composite active component in a solvent, adding a titanium precursor, stirring and reacting, and then allowing it to stand to obtain titanium-coated carbon ball powder of the anchored vanadium-tungsten composite active component.

6. The hollow-structure catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones as described in claim 5, characterized in that, The titanium precursor includes tetrabutyl titanate, titanium isopropoxide, or titanium tetrachloride. And / or, the solvent includes anhydrous ethanol; And / or, the mass ratio of vanadium in the carbon ball powder anchoring the vanadium-tungsten composite active component to titanium in the titanium precursor is 1:17-98. And / or, the temperature of the stirring reaction is 20-30°C and the time is 30-90 min; And / or, the settling temperature is 20-30℃ and the time is 10-20h; And / or, the temperature of the first calcination treatment is 400-550℃, and the time is 3-5h.

7. The hollow-structure catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones as described in claim 1, characterized in that, The chromium precursor includes chromium nitrate nonahydrate; And / or, the cerium precursor comprises cerium nitrate hexahydrate; And / or, the impregnation method includes the following steps: mixing a chromium precursor, a cerium precursor, titanium ball powder with vanadium-tungsten composite active components loaded on the inner surface of the hollow structure, and water, heating and stirring, and then drying.

8. The hollow-structure catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones as described in claim 7, characterized in that, The mass ratio of the chromium precursor, the cerium precursor, and the titanium ball powder with vanadium-tungsten composite active components loaded on the inner surface of the hollow structure is 0.055-0.29:0.025-0.14:1; And / or, the heating and stirring temperature is 30-60℃, and the time is 30-90 min; And / or, the drying temperature is 40-80°C; And / or, the temperature of the second calcination treatment is 400-550℃, and the time is 3-5h.

9. The application of a hollow-structured catalyst for the removal of nitrogen oxides and chlorinated organic compounds in reaction zones as described in any one of claims 1-8 in the synergistic removal of nitrogen oxides and chlorinated organic compounds in flue gas.

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