Core-shell structure catalytic material of high-entropy alloy coated with high-entropy oxide and preparation method of core-shell structure catalytic material

Abstract

The invention discloses a core-shell structure catalytic material of a high-entropy alloy coated with a high-entropy oxide and a preparation method, the core-shell structure catalytic material is used for synergistic removal of nitrogen oxides and volatile organic compounds, and the core of the core-shell structure catalytic material is a quinary non-noble metal high-entropy alloy; and the shell of the core-shell structure catalytic material is a quinary non-noble metal high-entropy oxide. The core-shell structure catalytic material of the high-entropy alloy coated with the high-entropy oxide according to the embodiment of the invention is relatively low in preparation cost, has excellent thermal stability, chemical stability, toxicity resistance and catalytic reaction activity, and can realize efficient synergistic removal of nitrogen oxides and volatile organic compounds.

Description

Technical Field

[0001] The present invention relates to the technical field of catalytic treatment of nitrogen oxides and volatile organic compounds, and in particular to a core-shell structured catalytic material with a high-entropy oxide coating on a high-entropy alloy and a preparation method thereof. Background Art

[0002] Nitrogen oxides (NOx) and volatile organic compounds (VOCs) are the main precursors for the formation of PM2.5 and O 3 and are likely to cause environmental problems such as photochemical smog and haze, posing potential risks to human health. In recent years, the prevention and control of air pollution in China has entered a new stage of coordinated control of PM2.5 and O 3 To meet environmental protection requirements and reduce the health hazards and environmental impacts caused by pollutant emissions, effective measures must be taken to treat NOx and VOCs.

[0003] Catalysts are the core for achieving efficient removal of pollutants. However, the catalysts in related technologies have low selectivity for the target product COx, accompanied by the generation of a large number of by-products such as dioxins and polycyclic aromatic hydrocarbons, presenting high environmental risks; moreover, the operating temperature range of the catalysts is narrow, and the anti-poisoning performance and thermal stability are poor. Noble metal catalysts have excellent low-temperature oxidation activity for VOCs, but their preparation cost is high, they are easily deactivated by flue gas components, and the active sites are prone to agglomeration at high temperatures, resulting in poor stability. Therefore, it is necessary to develop a new type of bifunctional catalyst with the ability to synergistically control multiple pollutants. Summary of the Invention

[0004] The present invention aims to at least solve one of the technical problems existing in the prior art. To this end, an object of the present invention is to provide a core-shell structured catalytic material with a high-entropy oxide coating on a high-entropy alloy, which has a relatively low preparation cost, excellent thermal stability, chemical stability, anti-poisoning property and catalytic reaction activity, and can achieve efficient synergistic removal of nitrogen oxides and volatile organic compounds.

[0005] According to an embodiment of the present invention, the core-shell structured catalytic material with a high-entropy oxide coating on a high-entropy alloy is used for the synergistic removal of nitrogen oxides and volatile organic compounds. The core of the core-shell structured catalytic material is a quinary non-noble metal high-entropy alloy, and the shell of the core-shell structured catalytic material is a quinary non-noble metal high-entropy oxide.

[0006] The core-shell structured catalytic material of high-entropy alloy coated with high-entropy oxide according to the embodiments of the present invention uses a quinary non-precious metal high-entropy alloy as the core of the core-shell structure and a quinary non-precious metal high-entropy oxide as the shell layer of the core-shell structure, constructing a core-shell structured catalytic material of high-entropy oxide coated with high-entropy alloy, effectively regulating the catalytic reaction activity, optimizing the distribution of surface active sites of the catalytic material, and having excellent thermal stability, chemical stability, anti-poisoning property and catalytic reaction activity. By utilizing the strong charge transfer effect formed at the core-shell interface, the catalytic reaction activity is further improved, and non-precious metals are used to reduce the preparation cost on the premise of ensuring the catalytic activity.

[0007] According to some embodiments of the present invention, the quinary non-precious metal high-entropy alloy is FeVMoWTi HEAs, and the quinary non-precious metal high-entropy oxide is (FeVMoWTi)xOy HEOs.

[0008] According to some embodiments of the present invention, it includes: preparing quinary non-precious metal high-entropy alloy nanoparticles by a carbon thermal shock method; preparing the quinary non-precious metal high-entropy oxide precursor; uniformly loading the quinary non-precious metal high-entropy oxide precursor on the surface of the quinary non-precious metal high-entropy alloy nanoparticles by a co-precipitation method; after washing, filtering, drying and calcining the obtained precipitate, forming a core-shell structured powder of the quinary non-precious metal high-entropy oxide coating the quinary non-precious metal high-entropy alloy; and performing ball milling on the core-shell structured powder to obtain the core-shell structured catalytic material of high-entropy oxide coated with high-entropy alloy.

[0009] According to some embodiments of the present invention, preparing quinary non-precious metal high-entropy alloy nanoparticles by a carbon thermal shock method includes: configuring a first metal precursor solution; uniformly loading the first metal precursor solution on the surface of carbon nanofibers; and then placing the obtained sample under an inert atmosphere for thermal shock to obtain quinary non-precious metal high-entropy alloy nanoparticles.

[0010] According to some embodiments of the present invention, the first metal precursor solution includes ferric chloride, vanadium chloride, molybdenum chloride, tungsten chloride and titanium chloride, the inert atmosphere is one of nitrogen, helium or argon, and the thermal shock parameters include: a thermal shock temperature of 1700 - 2000 °C, a thermal shock time of 50 - 55 ms, and a heating rate of 105 °C / s.

[0011] According to some embodiments of the present invention, the carbon nanofibers are synthesized by an electrospinning method, and the raw material for preparing the carbon nanofibers is polyacrylonitrile, and the carbonization temperature is 600 - 1000 °C.

[0012] According to some embodiments of the present invention, the quinary non-noble metal high-entropy oxide precursor is uniformly loaded on the surface of the quinary non-noble metal high-entropy alloy by a co-precipitation method, including: preparing a second metal precursor solution; adding the quinary non-noble metal high-entropy alloy nanoparticles into the second metal precursor solution and mixing uniformly; then adding NaOH to adjust the pH of the solution to form a precipitate.

[0013] According to some embodiments of the present invention, the second metal precursor solution includes ferric nitrate nonahydrate, ammonium metavanadate, ammonium heptamolybdate, ammonium metatungstate, and tetrabutyl titanate. The concentration of NaOH is 0.1 mol / L, and the pH of the solution is 8-11.

[0014] According to some embodiments of the present invention, in the process steps of washing, filtering, drying, and calcining the obtained precipitate: the drying temperature is 110 °C, the drying time is 12-18 h, the calcining temperature is 900 °C, and the calcining time is 1 h.

[0015] According to some embodiments of the present invention, in the process steps of ball milling the core-shell structure powder: the ball-to-material ratio is 8-15:1, the ball milling speed is 250-350 r / min, and the ball milling time is 30-60 h.

[0016] Additional aspects and advantages of the present invention will be given in part in the following description, become apparent in part from the following description, or be understood through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 is a schematic flow chart of a preparation method of a core-shell structure catalytic material of a high-entropy alloy coated with a high-entropy oxide according to some embodiments of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0018] The embodiments of the present invention will be described in detail below. The examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements with the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

[0019] For the core-shell structure catalytic material of a high-entropy alloy coated with a high-entropy oxide according to an embodiment of the present invention, the core-shell structure catalytic material is used for the synergistic removal of nitrogen oxides and volatile organic compounds. The core of the core-shell structure catalytic material is a quinary non-noble metal high-entropy alloy, and the shell of the core-shell structure catalytic material is a quinary non-noble metal high-entropy oxide.

[0020] The core-shell structured catalytic material of high-entropy oxide-coated high-entropy alloy according to an embodiment of the present invention uses a quinary non-noble metal high-entropy alloy as the core of the core-shell structure and a quinary non-noble metal high-entropy oxide as the shell layer of the core-shell structure, constructing a core-shell structured catalytic material of high-entropy oxide-coated high-entropy alloy, effectively regulating the catalytic reaction activity, optimizing the distribution of surface active sites of the catalytic material, and having excellent thermal stability, chemical stability, anti-poisoning property and catalytic reaction activity. By utilizing the strong charge transfer effect formed at the core-shell interface, the catalytic reaction activity is further improved, and non-noble metals are used to reduce the preparation cost on the premise of ensuring the catalytic activity.

[0021] According to some embodiments of the present invention, the quinary non-noble metal high-entropy alloy is FeVMoWTi HEAs, that is, a high-entropy alloy containing five non-noble metal elements of Fe, V, Mo, W, and Ti (the English abbreviation of high-entropy alloy is: HEAs); the quinary non-noble metal high-entropy oxide is (FeVMoWTi)xOy HEOs, that is, a high-entropy oxide containing five non-noble metal elements of Fe, V, Mo, W, and Ti (the English abbreviation of high-entropy oxide is HEOs). The present invention selects Fe, V, Mo, W, and Ti to synthesize high-entropy materials. Because transition metals are low in cost and have unique reactivity and electronic structures, the preparation cost is effectively reduced on the premise of ensuring the catalytic activity.

[0022] According to some embodiments of the present invention, it includes: preparing quinary non-noble metal high-entropy alloy nanoparticles by a carbothermal shock method. The carbothermal shock method has the characteristics of uniform temperature distribution, fast heating / cooling rate, high reaction temperature and short reaction time. Through the high-temperature carbothermal shock method of the present invention, the prepared quinary non-noble metal high-entropy alloy nanoparticles have the advantage of uniform particles; Preparing a quinary non-noble metal high-entropy oxide precursor. For example, the quinary non-noble metal high-entropy oxide precursor is prepared by mixing solutions of five metal compounds respectively containing Fe, V, Mo, W, and Ti; The quinary non-noble metal high-entropy oxide precursor is uniformly loaded on the surface of the quinary non-noble metal high-entropy alloy nanoparticles by a co-precipitation method. Among them, the co-precipitation method obtains nanoparticle precipitates through various chemical reactions in the solution. The process includes adding an alkaline solution such as NaOH to the solution to simultaneously precipitate multiple cations, forming a uniform precipitate of quinary non-noble metal high-entropy oxide-coated quinary non-noble metal high-entropy alloy. The precipitate nanomaterials prepared by this method have small particle size and uniform distribution; After washing, filtering, drying and calcining the obtained precipitate, a core-shell structured powder of quinary non-noble metal high-entropy oxide-coated quinary non-noble metal high-entropy alloy is formed; The core-shell structure powder is ball-milled to obtain a core-shell structure catalytic material with a high-entropy oxide coating a high-entropy alloy. Among them, the ball-milling treatment can be high-speed low-temperature ball-milling. Ball-milling the core-shell structure powder increases the specific surface area of the core-shell structure powder, exposes more surface active sites, and thus improves the catalytic activity.

[0023] According to some embodiments of the present invention, preparing five-element non-precious metal high-entropy alloy nanoparticles by a carbothermal shock method, including: Preparing a first metal precursor solution; Uniformly loading the first metal precursor solution on the surface of carbon nanofibers; then placing the obtained sample under an inert atmosphere for thermal shock to obtain five-element non-precious metal high-entropy alloy nanoparticles.

[0024] By uniformly loading the first metal precursor solution on the surface of carbon nanofibers and then performing thermal shock, five-element non-precious metal high-entropy alloy nanoparticles are obtained. This carbothermal shock method can obtain relatively uniform five-element non-precious metal high-entropy alloy nanoparticles.

[0025] According to some embodiments of the present invention, the first metal precursor solution includes iron chloride, vanadium chloride, molybdenum chloride, tungsten chloride, and titanium chloride, and the inert atmosphere is one of nitrogen, helium, or argon. The thermal shock parameters include: the thermal shock temperature is 1700 - 2000 °C, the thermal shock time is 50 - 55 ms, and the heating rate is 105 °C / s. By introducing an inert atmosphere, the material is protected from contact with hot air to prevent oxidation of the precursor solution during thermal shock.

[0026] For example, the concentrations of iron chloride, vanadium chloride, molybdenum chloride, tungsten chloride, and titanium chloride included in the first metal precursor solution are all 0.1 mol / L. Iron chloride, vanadium chloride, molybdenum chloride, tungsten chloride, and titanium chloride are all common, chemically stable, and inexpensive metal compounds, which can not only provide the metal elements required for the first metal precursor solution but also reduce the preparation cost.

[0027] According to some embodiments of the present invention, the carbon nanofibers are synthesized by electrospinning, and the raw material for preparing the carbon nanofibers is polyacrylonitrile, and the carbonization temperature is 600 - 1000 °C. The electrospinning method can prepare a variety of nanofibers with diameters as low as dozens of nanometers, and the nanofibers have good uniformity, ensuring that the five-element non-precious metal high-entropy alloy nanoparticles prepared during thermal shock are small in particle size and uniform in volume.

[0028] According to some embodiments of the present invention, a quinary non-noble metal high-entropy oxide precursor is uniformly loaded on the surface of a quinary non-noble metal high-entropy alloy by a co-precipitation method, including: preparing a second metal precursor solution; adding quinary non-noble metal high-entropy alloy nanoparticles to the second metal precursor solution and mixing uniformly; then adding NaOH to adjust the pH of the solution to form a precipitate. By adjusting an appropriate pH value, the generated precipitate is made more uniform and impurities are reduced.

[0029] According to some embodiments of the present invention, the second metal precursor solution includes ferric nitrate nonahydrate, ammonium metavanadate, ammonium heptamolybdate, ammonium metatungstate, and tetrabutyl titanate. The concentration of NaOH is 0.1 mol / L, and the pH of the solution is 8 - 11.

[0030] For example, the concentrations of ferric nitrate nonahydrate, ammonium metavanadate, ammonium heptamolybdate, ammonium metatungstate, and tetrabutyl titanate included in the second metal precursor solution are all 0.1 mol / L. Ferric nitrate nonahydrate, ammonium metavanadate, ammonium heptamolybdate, ammonium metatungstate, and tetrabutyl titanate are all common, chemically stable, and low-cost metal compounds, which can not only provide the metal elements required for the second metal precursor solution but also reduce the preparation cost.

[0031] According to some embodiments of the present invention, in the process steps of washing, filtering, drying, and calcining the obtained precipitate: the drying temperature is 110 °C, the drying time is 12 - 18 h, the calcining temperature is 900 °C, and the calcining time is 1 h. By washing and filtering the precipitate, impurities in the precipitate can be removed; by drying and calcining the precipitate, moisture in the precipitate can be removed, facilitating the next process.

[0032] According to some embodiments of the present invention, in the process step of ball-milling the core-shell structure powder: the ball-to-powder ratio is 8 - 15:1, the ball-milling rotation speed is 250 - 350 r / min, and the ball-milling time is 30 - 60 h. By ball-milling the core-shell structure powder, the specific surface area of the core-shell structure powder is increased, more surface active sites are exposed, and thus the catalytic activity is improved.

[0033] The core-shell structured catalytic material of high-entropy alloy coated with high-entropy oxide in some embodiments of the present invention has four core effects due to the high-entropy material, thus exhibiting excellent stability and catalytic activity. The core-shell structured catalytic material of high-entropy alloy coated with high-entropy oxide effectively regulates the catalytic reaction activity, optimizes the distribution of surface active sites of the catalytic material, and has excellent thermal stability, chemical stability, anti-poisoning property and catalytic reaction activity. By utilizing the strong charge transfer effect formed at the core-shell interface, the catalytic reaction activity is further improved. The core-shell structured catalytic material of high-entropy alloy coated with high-entropy oxide is subjected to ball milling treatment, effectively increasing the specific surface area of the core-shell structured powder, exposing more surface active sites, thereby improving the catalytic activity, having strong thermal stability, good corrosion resistance, and excellent performance in the synergistic removal of nitrogen oxides and volatile organic compounds.

[0034] The following specifically describes some core-shell structured catalytic materials of high-entropy alloy coated with high-entropy oxide and their preparation methods in the embodiments of the present invention through some specific examples.

[0035] Example 1, The core-shell structured catalytic material of high-entropy alloy coated with high-entropy oxide for the synergistic removal of nitrogen oxides and volatile organic compounds in Example 1 and its preparation method. The specific steps of the preparation method include: (1) Dissolve polyacrylonitrile in dimethylformamide to prepare a 10 wt% electrospinning solution. Set the electrospinning voltage to 15 kV, the receiving distance to 10 cm, and the receiver rotation speed to 2500 r / min. Stabilize the obtained fibers in a forced-air drying oven at 260 °C for 6 hours, and then carbonize them at 600 °C for 1 hour under a nitrogen atmosphere to obtain carbon nanofibers. Prepare ethanol solutions of ferric chloride, vanadium chloride, molybdenum chloride, tungsten chloride, and titanium chloride with a concentration of 0.1 mol / L respectively, mix them evenly, take an appropriate amount of the above carbon nanofibers, uniformly load the mixed solution on the surface of the carbon nanofibers and dry it at room temperature. Then fix the obtained sample on a copper support and transfer it to a nitrogen atmosphere for rapid thermal shock. The thermal shock temperature is 1700 °C, the shock time is 50 ms, and the heating rate is 105 °C / s to obtain five-element non-precious metal high-entropy alloy nanoparticles.

[0036] (2) Prepare solutions of ferric nitrate nonahydrate, ammonium metavanadate, ammonium heptamolybdate, ammonium metatungstate, and tetrabutyl titanate with a concentration of 0.1 mol / L respectively, mix them evenly, add an appropriate amount of the five-element non-precious metal high-entropy alloy nanoparticles obtained in step (1), mix them evenly, then add an appropriate amount of NaOH solution with a concentration of 0.1 mol / L to adjust the pH of the solution to 8. Wash, filter, and dry the obtained precipitate at 110 °C for 12 h, and then calcine it at 900 °C for 1 h to obtain five-element non-precious metal high-entropy oxide coated five-element non-precious metal high-entropy alloy core-shell powder.

[0037] (3) Take the powder obtained in Step 3 and perform rapid low-temperature ball milling treatment. The ball-to-material ratio is 8:1, the ball milling speed is 250 r / min, and the ball milling time is 30 h to obtain the target core-shell structured catalytic material of high-entropy alloy coated with high-entropy oxide.

[0038] Example 2 The core-shell structured catalytic material of high-entropy alloy coated with high-entropy oxide for the synergistic removal of nitrogen oxides and volatile organic compounds in Example 2 and its preparation method. The specific steps of the preparation method include: (1) Dissolve polyacrylonitrile in dimethylformamide to make a 10 wt% electrospinning solution. Set the electrospinning voltage to 15 kV, the receiving distance to 10 cm, and the receiver rotation speed to 2500 r / min. Stabilize the obtained fibers in a blast drying oven at 260 °C for 6 hours, and then carbonize them at 700 °C for 1 hour in a nitrogen atmosphere to obtain carbon nanofibers. Prepare ethanol solutions of ferric chloride, vanadium chloride, molybdenum chloride, tungsten chloride, and titanium chloride with a concentration of 0.1 mol / L respectively, mix them evenly, take an appropriate amount of the above carbon nanofibers, uniformly load the mixed solution on the surface of the carbon nanofibers and dry it at room temperature. Then fix the obtained sample on a copper support and transfer it to a nitrogen atmosphere for rapid thermal shock. The thermal shock temperature is 1800 °C, the shock time is 52 ms, and the heating rate is 105 °C / s to obtain five-element non-precious metal high-entropy alloy nanoparticles.

[0039] (2) Prepare solutions of ferric nitrate nonahydrate, ammonium metavanadate, ammonium heptamolybdate, ammonium metatungstate, and tetrabutyl titanate with a concentration of 0.1 mol / L respectively, mix them evenly, add an appropriate amount of the five-element non-precious metal high-entropy alloy nanoparticles obtained in Step (1), mix them evenly, then add an appropriate amount of NaOH solution with a concentration of 0.1 mol / L to adjust the pH of the solution to 9. Wash, filter, and dry the obtained precipitate at 110 °C for 14 h, and then calcine it at 900 °C for 1 h to obtain a core-shell powder of five-element non-precious metal high-entropy oxide coated with five-element non-precious metal high-entropy alloy.

[0040] (3) Take the powder obtained in Step 3 and perform rapid low-temperature ball milling treatment. The ball-to-material ratio is 10:1, the ball milling speed is 270 r / min, and the ball milling time is 40 h to obtain the target core-shell structured catalytic material of high-entropy alloy coated with high-entropy oxide.

[0041] Example 3 The core-shell structured catalytic material of high-entropy alloy coated with high-entropy oxide for the synergistic removal of nitrogen oxides and volatile organic compounds in Example 3 and its preparation method. The specific steps of the preparation method include: (1) Dissolve polyacrylonitrile in dimethylformamide to prepare a 10 wt% electrospinning solution. Set the electrospinning voltage to 15 kV, the receiving distance to 10 cm, and the receiver rotation speed to 2500 r / min. Stabilize the obtained fibers in a blast drying oven at 260 °C for 6 hours, and then carbonize them at 800 °C for 1 hour under a nitrogen atmosphere to obtain carbon nanofibers. Prepare ethanol solutions of ferric chloride, vanadium chloride, molybdenum chloride, tungsten chloride, and titanium chloride with concentrations of 0.1 mol / L respectively, mix them evenly, take an appropriate amount of the above carbon nanofibers, uniformly load the mixed solution on the surface of the carbon nanofibers and dry at room temperature. Then fix the obtained sample on a copper holder and transfer it to a helium atmosphere for rapid thermal shock. The thermal shock temperature is 1900 °C, the shock time is 54 ms, and the heating rate is 105 °C / s to obtain five-element non-noble metal high-entropy alloy nanoparticles.

[0042] (2) Prepare solutions of ferric nitrate nonahydrate, ammonium metavanadate, ammonium heptamolybdate, ammonium metatungstate, and tetrabutyl titanate with concentrations of 0.1 mol / L respectively, mix them evenly, add an appropriate amount of the five-element non-noble metal high-entropy alloy nanoparticles obtained in step (1), mix them evenly, then add an appropriate amount of NaOH solution with a concentration of 0.1 mol / L to adjust the pH of the solution to 10. Wash, filter, and dry the obtained precipitate at 110 °C for 16 h, and then calcine it at 900 °C for 1 h to obtain five-element non-noble metal high-entropy oxide-coated five-element non-noble metal high-entropy alloy core-shell powder.

[0043] (3) Take the powder obtained in step 3 and perform rapid low-temperature ball milling treatment. The ball-to-material ratio is 13:1, the ball milling speed is 300 r / min, and the ball milling time is 50 h to obtain the target high-entropy oxide-coated high-entropy alloy core-shell structure catalytic material.

[0044] Example 4 The core-shell structure catalytic material of high-entropy oxide-coated high-entropy alloy for the synergistic removal of nitrogen oxides and volatile organic compounds in Example 4 and its preparation method. The specific steps of the preparation method include: (1) Dissolve polyacrylonitrile in dimethylformamide to prepare a 10 wt% electrospinning solution. Set the electrospinning voltage to 15 kV, the receiving distance to 10 cm, and the receiver rotation speed to 2500 r / min. Stabilize the obtained fibers in a blast drying oven at 260 °C for 6 hours, and then carbonize them at 900 °C for 1 hour under a nitrogen atmosphere to obtain carbon nanofibers. Prepare ethanol solutions of ferric chloride, vanadium chloride, molybdenum chloride, tungsten chloride, and titanium chloride with concentrations of 0.1 mol / L respectively, mix them evenly, take an appropriate amount of the above carbon nanofibers, evenly load the mixed solution on the surface of the carbon nanofibers and dry at room temperature. Then fix the obtained sample on a copper support and transfer it to an argon atmosphere for rapid thermal shock. The thermal shock temperature is 2000 °C, the shock time is 55 ms, and the heating rate is 105 °C / s to obtain five-element non-precious metal high-entropy alloy nanoparticles.

[0045] (2) Prepare solutions of ferric nitrate nonahydrate, ammonium metavanadate, ammonium heptamolybdate, ammonium metatungstate, and tetrabutyl titanate with concentrations of 0.1 mol / L respectively, mix them evenly, add an appropriate amount of the five-element non-precious metal high-entropy alloy nanoparticles obtained in step (1), mix them evenly, then add an appropriate amount of NaOH solution with a concentration of 0.1 mol / L to adjust the pH of the solution to 11. Wash, filter, and dry the obtained precipitate at 110 °C for 18 h, and then calcine it at 900 °C for 1 h to obtain five-element non-precious metal high-entropy oxide-coated five-element non-precious metal high-entropy alloy core-shell powder.

[0046] (3) Take the powder obtained in step 3 and perform rapid low-temperature ball milling treatment. The ball-to-material ratio is 15:1, the ball milling speed is 330 r / min, and the ball milling time is 50 h to obtain the target high-entropy oxide-coated high-entropy alloy core-shell structure catalytic material.

[0047] Example 5 The core-shell structure catalytic material of high-entropy oxide-coated high-entropy alloy for the synergistic removal of nitrogen oxides and volatile organic compounds in Example 5 and its preparation method. The specific steps of the preparation method include: (1) Dissolve polyacrylonitrile in dimethylformamide to prepare a 10 wt% electrospinning solution. Set the electrospinning voltage to 15 kV, the receiving distance to 10 cm, and the receiver rotation speed to 2500 r / min. Stabilize the obtained fibers in a blast drying oven at 260 °C for 6 hours, and then carbonize them at 800 °C for 1 hour under a nitrogen atmosphere to obtain carbon nanofibers. Prepare ethanol solutions of ferric chloride, vanadium chloride, molybdenum chloride, tungsten chloride, and titanium chloride with a concentration of 0.1 mol / L respectively, mix them evenly, take an appropriate amount of the above carbon nanofibers, uniformly load the mixed solution on the surface of the carbon nanofibers and dry it at room temperature. Then fix the obtained sample on a copper support and transfer it to an argon atmosphere for rapid thermal shock. The thermal shock temperature is 2000 °C, the shock time is 55 ms, and the heating rate is 105 °C / s to obtain five-element non-precious metal high-entropy alloy nanoparticles.

[0048] (2) Prepare solutions of ferric nitrate nonahydrate, ammonium metavanadate, ammonium heptamolybdate, ammonium metatungstate, and tetrabutyl titanate with a concentration of 0.1 mol / L respectively, mix them evenly, add an appropriate amount of the five-element non-precious metal high-entropy alloy nanoparticles obtained in step (1), mix them evenly, then add an appropriate amount of NaOH solution with a concentration of 0.1 mol / L to adjust the pH of the solution to 11. Wash, filter, and dry the obtained precipitate at 110 °C for 16 h, and then calcine it at 900 °C for 1 h to obtain five-element non-precious metal high-entropy oxide-coated five-element non-precious metal high-entropy alloy core-shell powder.

[0049] (3) Take the powder obtained in step 3 and perform rapid low-temperature ball milling treatment. The ball-to-material ratio is 15:1, the ball milling speed is 350 r / min, and the ball milling time is 60 h to obtain the target high-entropy oxide-coated high-entropy alloy core-shell structure catalytic material.

[0050] In the description of this specification, the description referring to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0051] Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the claims and their equivalents.

Claims

1. A high entropy oxide-coated high entropy alloy core-shell structure catalytic material, characterized in that: The core-shell structure catalytic material is used for the coordinated removal of nitrogen oxides and volatile organic compounds. The core of the core-shell structure catalytic material is a five-element non-precious metal high entropy alloy, and the shell of the core-shell structure catalytic material is a five-element non-precious metal high entropy oxide.

2. The high entropy oxide-coated high entropy alloy core-shell structure catalytic material according to claim 1, characterized in that: The five-element non-precious metal high entropy alloy is FeVMoWTi HEAs, and the five-element non-precious metal high entropy oxide is (FeVMoWTi) x O y HEOs.

3. A method for preparing a core-shell structure catalytic material of a high entropy oxide coated high entropy alloy, characterized in that: include: Five-element non-precious metal high entropy alloy nanoparticles were prepared by carbon thermal shock method; Preparing the five-element non-noble metal high entropy oxide precursor; The five-element non-noble metal high entropy oxide precursor is uniformly loaded on the surface of the five-element non-noble metal high entropy alloy nanoparticles by a co-precipitation method; The obtained precipitate is washed, filtered, dried and calcined to form a core-shell structure powder of a five-element non-noble metal high entropy oxide coated with a five-element non-noble metal high entropy alloy; The core-shell structure powder is subjected to ball milling treatment to obtain a core-shell structure catalytic material of a high entropy alloy coated with a high entropy oxide.

4. The method for preparing a core-shell structure catalytic material of a high entropy oxide coated high entropy alloy according to claim 3, characterized in that: Five-element non-precious metal high entropy alloy nanoparticles are prepared by carbon thermal shock method, including: preparing a first metal precursor solution; uniformly loading the first metal precursor solution on the surface of the carbon nanofibers; The obtained sample was then placed in an inert atmosphere for thermal shock to obtain five-element non-precious metal high entropy alloy nanoparticles.

5. The method for preparing a core-shell structure catalytic material of a high entropy oxide coated high entropy alloy according to claim 4, characterized in that: The first metal precursor solution includes ferric chloride, vanadium chloride, molybdenum chloride, tungsten chloride and titanium chloride, the inert atmosphere is one of nitrogen, helium or argon, and the thermal shock parameters include: thermal shock temperature of 1700-2000°C, thermal shock time of 50-55ms, and heating rate of 105°C / s.

6. The method for preparing a core-shell structure catalytic material of a high entropy oxide coated high entropy alloy according to claim 4, characterized in that: The carbon nanofiber is synthesized by electrostatic spinning. The raw material for preparing the carbon nanofiber is polyacrylonitrile and the carbonization temperature is 600-1000°C.

7. The method for preparing a core-shell structure catalytic material of a high entropy oxide coated high entropy alloy according to claim 3, characterized in that: The five-element non-noble metal high entropy oxide precursor is uniformly loaded on the surface of the five-element non-noble metal high entropy alloy by a co-precipitation method, comprising: preparing a second metal precursor solution; Adding the five-element non-noble metal high entropy alloy nanoparticles to the second metal precursor solution and mixing them evenly; NaOH was then added to adjust the pH of the solution to form a precipitate.

8. The method for preparing a core-shell structure catalytic material of a high entropy oxide coated high entropy alloy according to claim 7, characterized in that: The second metal precursor solution includes ferric nitrate nonahydrate, ammonium metavanadate, ammonium heptamolybdate, ammonium metatungstate and tetra-n-butyl titanate, the NaOH concentration is 0.1 mol / L, and the solution pH is 8-11.

9. The method for preparing a core-shell structure catalytic material of a high entropy oxide coated high entropy alloy according to claim 3, characterized in that: In the process steps of washing, filtering, drying and calcining the obtained precipitate: the drying temperature is 110°C, the drying time is 12-18 hours, the calcination temperature is 900°C, and the calcination time is 1 hour.

10. The method for preparing a core-shell structure catalytic material of a high entropy oxide coated high entropy alloy according to claim 3, characterized in that: In the process step of ball milling the core-shell structure powder, the ball-to-material ratio is 8-15:1, the ball milling speed is 250-350 r / min, and the ball milling time is 30-60 h.

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