Fluorine-doped high-entropy oxide catalyst as well as preparation method and application thereof
By using fluorine-doped high-entropy oxide catalysts, the problem of catalyst poisoning in low-temperature wet flue gas was solved. This enabled efficient catalysis of VOCs in wet flue gas while maintaining the balance between the catalyst's water resistance and activity, thus improving the catalyst's stability and service life.
Patent Information
- Application Number
- CN202511727340.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-24
- Publication Date
- 2026-02-27
AI Technical Summary
Existing catalysts are prone to poisoning under low-temperature and humid flue gas conditions, which leads to a decrease in pollutant control efficiency and makes it difficult to achieve a balance between maintaining water resistance and catalytic activity.
A fluorine-doped high-entropy oxide catalyst was prepared by combining F with a high-entropy oxide support. The catalyst has both oxidation activity and stability. The water resistance of F and the multi-component synergistic effect of high-entropy oxide are utilized to avoid the inhibition of catalytic activity by F.
It achieves efficient catalysis of VOCs in wet flue gas while maintaining the catalyst's resistance to water poisoning and long-term stability. The catalytic activity decreases slightly under the influence of water vapor but can recover, significantly improving the catalyst's service life.
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Figure CN121571173A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalysis technology, and relates to a fluorine-doped high-entropy oxide catalyst, its preparation method, and its application. Background Technology
[0002] Low-temperature catalysts can reduce energy consumption in the catalytic control of pollutants in combustion flue gas, which is of great significance for industrial energy conservation and emission reduction. However, under low-temperature conditions, the water vapor content in the flue gas increases, leading to catalyst poisoning and a significant decrease in pollutant control efficiency. Therefore, developing new catalysts to solve the problem of catalyst water poisoning is of great significance for reducing enterprise energy consumption and improving flue gas pollutant control efficiency.
[0003] Modification with fluorine (F) is a key strategy for imparting water resistance to material surfaces, primarily due to F's high electronegativity and low polarizability. When fluorine replaces surface oxygen or forms M–F bonds with metals, its outer 2p electron cloud becomes extremely dense, resulting in a stable negative potential layer on the surface. This allows the positively charged hydrogen terminals (Hδ) of water molecules to be effectively neutralized. + The M–F bonds are difficult for water molecules to approach, thus significantly inhibiting the physical adsorption and chemical dissociation of water molecules. Furthermore, the M–F bonds possess extremely high bond energy and chemical inertness, making them difficult for water molecules to attack or break, resulting in a significant reduction in surface energy and weakened surface polarity. Therefore, fluorine doping achieves electrostatic repulsion and chemical inertization of water molecules by constructing a low-polarity, highly dense electron cloud surface environment, thereby endowing the material with excellent water resistance and hydrophobic stability.
[0004] However, current research rarely uses fluorine (F) to modify metal oxides to improve their water resistance during catalysis. The main reason is that the high electronegativity and strong electron-withdrawing properties of fluorine often disrupt the electronic structure stability of the metal-oxygen bond, leading to a significant decrease in catalytic activity. Specifically, the M–F bond energy formed after F replaces surface oxygen is extremely high, almost completely absent from the redox cycle, inhibiting the migration and activation of lattice oxygen, thus reducing oxygen vacancy concentration and hindering the redox cycle. Simultaneously, the strong electron-withdrawing effect of F leads to enhanced localization of transition metal d orbitals, weakening metal-oxygen covalentity, thereby reducing surface active oxygen (O2). - O - The ability to generate and react with fluorine (F) is limited. Therefore, although F can impart excellent hydrophobicity to materials, its strong electron binding effect and chemical inertness often lead to "passivation" of catalytic sites, becoming a key factor limiting its application in metal oxide catalytic systems.
[0005] Furthermore, for conventional metal oxide catalysts (which do not have high-entropy structures) and undoped high-entropy oxide catalysts in existing technologies, water vapor in the flue gas can cause catalyst poisoning and reduce pollutant control efficiency during the catalytic reaction of VOCs in wet flue gas.
[0006] Therefore, developing a fluorine-doped high-entropy oxide catalyst that maintains a stable and efficient balance between water resistance and catalytic activity in pollutant control is a current research focus. Summary of the Invention
[0007] The purpose of this invention is to overcome the shortcomings of the prior art and provide a fluorine-doped high-entropy oxide catalyst, its preparation method and application. By combining the fluorine doping strategy with a high-entropy oxide support, a fluorine-doped high-entropy oxide is prepared. As a catalyst, it has good oxidation activity for VOCs. When catalyzing VOCs in wet flue gas, it exhibits higher catalyst efficiency and catalytic stability, that is, it has good resistance to water vapor poisoning.
[0008] The objective of this invention is achieved through the following technical solutions: The first aspect of this invention provides a method for preparing a fluorine-doped high-entropy oxide catalyst, comprising: (1) Manganese salt, cerium salt, praseodymium salt, zirconium salt, yttrium salt, glycine, and trifluoroacetamide were dissolved together in deionized water and stirred at room temperature for 2-4 h to obtain a uniform light green precursor solution. (2) Place the precursor solution in a drying oven at 60-90℃ for 10-14 h to obtain a gel-like precursor; (3) The gel-like precursor was calcined at 500-700℃ for 20-40 minutes in air atmosphere, and then quickly taken out and quenched at room temperature to obtain fluorine-doped high-entropy oxide catalyst.
[0009] Further, the manganese salt, cerium salt, praseodymium salt, zirconium salt, and yttrium salt are water-soluble salts. Specifically, the manganese salt is manganese nitrate or manganese acetate tetrahydrate or manganese chloride tetrahydrate; the cerium salt is cerium nitrate hexahydrate or cerium(III) acetate hexahydrate or cerium(III) chloride heptahydrate; the praseodymium salt is praseodymium nitrate hexahydrate or praseodymium(III) acetate hexahydrate or praseodymium(III) chloride heptahydrate; the zirconium salt is zirconium nitrate pentahydrate or zirconium acetate or zirconium chloride octahydrate; and the yttrium salt is yttrium nitrate hexahydrate or yttrium(III) acetate tetrahydrate or yttrium chloride hexahydrate. Furthermore, the molar ratio of metal ions in the manganese salt, cerium salt, praseodymium salt, zirconium salt, and yttrium salt is 1:1:1:1:1.
[0010] Furthermore, in the precursor solution, the molar ratio of metal ions, glycine, and ammonium trifluoroacetate is 0.5-0.8:8-12:0.005-0.02.
[0011] Furthermore, the gel-like precursor is placed in a quartz boat and then placed in a preheated tube furnace at 500-700°C. A calcination temperature of 600°C is further preferred.
[0012] Furthermore, the stirring speed is 450-600 r / min.
[0013] A second aspect of the present invention provides a fluorine-doped high-entropy oxide catalyst obtained by the preparation method described above, having the general chemical formula (MnCeZrPrY)OO. v -F, where F element partially replaces oxygen atoms, and oxygen vacancies O are present in the material. v .
[0014] A third aspect of the present invention provides the application of the fluorine-doped high-entropy oxide catalyst in the catalytic oxidation of VOCs.
[0015] Furthermore, the catalyst sample was placed in the reactor, and 40 ppm acetone, 5 vol% O2 and carrier gas N2 were introduced, along with 5-10 vol% water vapor. The outlet concentration of acetone was monitored, and its removal efficiency was calculated.
[0016] Furthermore, the formula for the catalytic efficiency of VOCs is: Where η represents the catalytic oxidation efficiency, C (in) It is the concentration (ppm) of the pollutants entering the reactor. C (out) It is the pollutant concentration (ppm) at the reactor outlet.
[0017] Furthermore, the temperature of the catalytic reaction is 150-200℃.
[0018] In this application, the applicant innovatively proposes the preparation of F-doped high-entropy oxide catalysts, utilizing the water resistance of F materials to overcome the problem of F poisoning of conventional metal oxides, achieving a highly efficient balance between water resistance and catalytic activity in pollutant control. Compared with traditional single-metal oxide systems, this invention utilizes F to modify high-entropy oxides (HEO) to overcome the problem of "F-induced activity reduction," fundamentally due to the multi-component synergistic effect and electronic structure harmonization ability of high-entropy systems. In conventional metal oxides (such as MnO...) x In high-entropy oxides, the high electronegativity of F strongly attracts electrons, forming stable Mn–F bonds, leading to enhanced electron localization and hindered oxygen migration, thus significantly inhibiting catalytic activity. However, in high-entropy oxides, due to the different electronegativity, coordination environments, and M–O bond energies of various metals (such as Mn, Ce, Pr, Zr, and Y), F does not uniformly replace all oxygens but selectively dopes, preferentially binding to oxygen sites adjacent to metals with lower electronegativity and weaker activity (such as Zr and Y), thereby spatially avoiding major active centers (such as Mn and Ce). Simultaneously, the electronic complementarity effect between multiple metals can be adjusted through valence state regulation (e.g., Ce…). 4+ / Ce 3+ Mn 4+ / Mn 3+ (Conversion) achieves charge compensation, maintaining the overall balance between oxygen vacancies and redox cycles. Furthermore, the inherent lattice distortion and high configurational entropy of the high-entropy system effectively disperse the local structural disturbances caused by F doping, avoiding the formation of inert fluoride phases. Therefore, in high-entropy oxides, F doping transforms from a "passivation" effect to a "synergistic regulation" effect, achieving a design advantage that balances water resistance and catalytic activity.
[0019] The advantages and positive effects of this invention are: (1) This invention combines an F doping strategy with a high-entropy oxide support, transforming the role of F from an "active poisoner" in the traditional system to a "synergistic regulator" in the high-entropy system. This results in a catalyst exhibiting reversible resistance to water poisoning and long-term stability in the catalytic oxidation of VOCs, achieving a highly efficient synergy between water resistance and catalytic activity. In wet flue gas containing 5% water vapor, the catalyst of this invention is minimally affected by water vapor (as low as 3%) in the catalytic oxidation of VOCs (such as acetone), far lower than that of undoped high-entropy oxide catalysts (activity decreases by up to 28%), demonstrating excellent water resistance and stability. Furthermore, its catalytic activity can be completely restored after the water vapor is removed, indicating that F doping transforms the water poisoning process from irreversible to a reversible dynamic regulation process, greatly improving the catalyst's lifespan. In wet flue gas, it not only exhibits strong resistance to poisoning but also maintains high catalytic efficiency for VOCs (e.g., the conversion rate of acetone can still reach over 89% at 180℃).
[0020] (2) The catalyst preparation method of this invention is simple. The fluorine doping process does not destroy the main crystal structure of the high-entropy oxide (maintaining a single fluorite phase), and at the same time successfully introduces oxygen vacancies that promote the catalytic reaction. The glycine-solution combustion method used is simple and mild, and is suitable for large-scale preparation. Attached Figure Description
[0021] Figure 1 (MnCeZrPrY)OO, as in Example 1 v -F 0.1 XRD pattern of (MnCeZrPrY)O2 and standard pattern of fluorite phase crystal in Comparative Example 1; Figure 2 (MnCeZrPrY)OO, as in Example 1 v -F 0.1 XPS 1s spectrum of (MnCeZrPrY)O2 in Comparative Example 1, where (a) is the (MnCeZrPrY)O2 spectrum. v -F 0.1 (b) is (MnCeZrPrY)O2; Figure 3 High-entropy oxides (MnCeZrPrY)O2 and (MnCeZrPrY)OO v -F 0.1 A comparison chart of catalytic activities; Figure 4 The catalyst activity diagrams are shown before and after F doping of MnO2. Figure 5 Figure 1 shows the effect of water vapor on high-entropy catalysts with different fluorine doping concentrations. Figure 6 The graph shows the effect of water vapor on catalytic activity and stability in Example 1 and Comparative Example 1. Figure 7 The diagram shows the catalytic activity of high-entropy catalysts with different fluorine doping levels in dry flue gas. Figure 8 The diagram shows the catalytic activity of high-entropy catalysts with different fluorine doping levels in wet flue gas. Detailed Implementation
[0022] The present invention will be further described in detail below through specific embodiments. The following embodiments are merely descriptive and not limiting, and should not be used to limit the scope of protection of the present invention.
[0023] The manganese nitrate (Mn(NO3)2), cerium nitrate hexahydrate (Ce(NO3)3·6H2O), zirconium nitrate pentahydrate (Zr(NO3)4·5H2O), yttrium nitrate hexahydrate (Y(NO3)3·6H2O), glycine, and ammonium trifluoroacetate used in the following examples were all purchased from Shanghai Maclean Biochemical Technology Co., Ltd. Praseodymium nitrate hexahydrate (Pr(NO3)3·6H2O) was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.
[0024] Example 1 A method for preparing a fluorine-doped high-entropy oxide catalyst, comprising: (1) Dissolve 0.1 mol of each of Mn(NO3)2, Ce(NO3)3·6H2O, Pr(NO3)3·6H2O, Zr(NO3)4·5H2O, and Y(NO3)3·6H2O, along with 10 mol of glycine and 0.01 mol of ammonium trifluoroacetate in 200 mL of deionized water and stir at 500 r / min at room temperature for 2 h to obtain a uniform light green precursor solution.
[0025] (2) The precursor solution was dried in a drying oven at 80°C for 12 h to remove moisture, resulting in a gel-like precursor. (3) The obtained gel-like precursor was placed in a quartz boat and directly placed into a preheated tube furnace at 600℃. It was calcined in air for 30 min, and then the sample was quickly taken out and quenched at room temperature to obtain a fluorine-doped high-entropy oxide catalyst. The obtained sample was named (MnCeZrPrY)OO. v -F 0.1 (0.1 represents the molar ratio of amine trifluoroacetate to the metal precursor (0.01 / 0.1)).
[0026] Example 2 A method for preparing a fluorine-doped high-entropy oxide catalyst, comprising: (1) Dissolve 0.1 mol of each of Mn(NO3)2, Ce(NO3)3·6H2O, Pr(NO3)3·6H2O, Zr(NO3)4·5H2O, and Y(NO3)3·6H2O, along with 10 mol of glycine and 0.1 mol of ammonium trifluoroacetate in 200 mL of deionized water and stir at 500 r / min at room temperature for 3 h to obtain a uniform light green precursor solution.
[0027] (2) The precursor solution was dried in a drying oven at 90°C for 12 h to remove moisture, resulting in a gel-like precursor. (3) The obtained gel-like precursor was placed in a quartz boat and directly placed into a preheated 700℃ tube furnace. It was calcined in air for 40 min, and then the sample was quickly taken out and quenched at room temperature to obtain a fluorine-doped high-entropy oxide catalyst. The obtained sample was named (MnCeZrPrY)OO. v -F1 (1 represents the molar ratio of amine trifluoroacetate to the metal precursor (0.1 / 0.1)).
[0028] Example 3 A method for preparing a fluorine-doped high-entropy oxide catalyst, comprising: (1) Dissolve 0.1 mol of each of Mn(NO3)2, Ce(NO3)3·6H2O, Pr(NO3)3·6H2O, Zr(NO3)4·5H2O, and Y(NO3)3·6H2O, along with 10 mol of glycine and 0.005 mol of ammonium trifluoroacetate in 200 mL of deionized water and stir at 500 r / min at room temperature for 3 h to obtain a uniform light green precursor solution.
[0029] (2) The precursor solution was dried in a drying oven at 60°C for 10 h to remove moisture, resulting in a gel-like precursor. (3) The obtained gel-like precursor was placed in a quartz boat and directly placed into a preheated 700℃ tube furnace. It was calcined in air for 40 min, and then the sample was quickly taken out and quenched at room temperature to obtain a fluorine-doped high-entropy oxide catalyst. The sample was named (MnCeZrPrY)OO. v -F 0.05 (0.05 represents the molar ratio of amine trifluoroacetate to the metal precursor (0.005 / 0.1)).
[0030] Comparative Example 1 The only difference from Example 1 is that amine trifluoroacetate was not added, and a high-entropy oxide catalyst was prepared, which was named (MnCeZrPrY)O2.
[0031] The high-entropy oxide catalyst prepared in Comparative Example 1 and the fluorine-doped high-entropy oxide catalyst (MnCeZrPrY) prepared in Example 1 v -F 0.1 XRD pattern as shown Figure 1 As shown, the XPS O 1s spectrum is as follows: Figure 2 As shown. According to Figure 1 It can be seen that the high-entropy oxide catalyst has a typical fluorite structure and conforms to the unique single-phase structure of high-entropy materials. In Example 1, F doping did not affect the crystal structure of the material, and the material still possesses a single fluorite structure. Figure 2 It can be seen that at this time, F replaces some of the O atoms in the material, and more oxygen vacancy structures (Ov) are generated due to the need to balance the internal charge of the material.
[0032] Comparative Example 2 0.1 mol MnO2, 10 mol glycine, and 0.01 mol ammonium trifluoroacetate were dissolved together in 200 mL of deionized water and stirred at 500 r / min at room temperature for 2 h to obtain a uniform light green precursor solution.
[0033] The precursor solution was dried in a drying oven at 80°C for 12 hours to remove moisture, yielding a gel-like precursor. The obtained gelatinous precursor was placed in a quartz boat and directly placed into a preheated tube furnace at 600℃. It was calcined in air for 30 min, and then the sample was quickly removed and quenched at room temperature to obtain a fluorine-doped oxide catalyst, which was named MnO-O. v -F 0.1 (0.1 represents the molar ratio of amine trifluoroacetate to the metal precursor (0.01 / 0.1)).
[0034] Comparative Example 3 The only difference from Example 1 is that Ce(NO3)3·6H2O in step (1) is replaced with Cu(NO3)3·6H2O.
[0035] Replacing Ce(NO3)3·6H2O with Cu(NO3)3·6H2O resulted in a ~20% decrease in the activity of the synthesized catalyst. This is because the replacement element makes it difficult to form a single-phase high-entropy oxide, which weakens the synergistic effect between metal atoms within the material (only in a high-entropy structure, where multiple metal atoms are randomly distributed in the same lattice, can better electron transfer and synergistic effects be demonstrated), thus reducing catalytic activity.
[0036] Specifically: In the fluorite-type (Fm3m) structure, the metal ion is usually in the +3 or +4 valence and is located next to O. 2- At the site of coordination in a cubic octahedron or a slightly distorted location. Ce 4+ (0.97 Å, CN=8) or Ce 3+ (1.14 Å) can well match the large cation sites in the fluorite lattice, forming a high-entropy oxide with a fluorite structure. When Cu 2+ When Cu replaces Ce (0.73 Å, CN=6), 2+ The radius is significantly smaller, and it tends to be six-coordinate (octahedral) rather than eight-coordinate, causing the local structure to no longer maintain the long-range order of fluorite, thus promoting phase separation. Therefore, after replacing Ce with Cu, the catalyst is difficult to form a high-entropy structure, the metal synergistic effect is weakened, and the activity is reduced.
[0037] Comparative Example 4 The only difference from Example 1 is that in step (1), 0.125 mol of each of Mn, Ce, Zr and Pr, 10 mol of glycine and 0.01 mol of ammonium trifluoroacetate were dissolved together in 200 mL of deionized water and stirred at 500 r / min at room temperature for 2 h to obtain a homogeneous precursor solution.
[0038] The activity of the obtained quaternary catalyst decreased by ~25%. This is because the quaternary metal components are difficult to form high-entropy oxides, lacking the high-entropy structure to impart reactive performance to the catalyst. In multi-component oxides, differences in the radius, valence, and crystal field strength of different metal cations lead to a large enthalpy of mixing (ΔH). mix This can easily lead to phase separation or multiphase coexistence. When the number of metals is small (e.g., 4-membered), the increase in mixing entropy is low, and the system is more prone to phase separation, making it difficult to form a single-phase high-entropy oxide. Therefore, although the intrinsic catalytic activity of Y oxide is very weak (Y oxide's catalytic efficiency for VOCs is <10%), the quaternary catalyst synthesized without adding Y has a significantly reduced overall catalyst activity because it is difficult to form a high-entropy structure and the synergistic effect between metal atoms is weakened.
[0039] The VOCs catalytic activity of the catalysts prepared in the examples and comparative examples was tested: At 180°C, the catalyst samples were placed in a reactor, and 40 ppm acetone, 5 vol% O2, and carrier gas N2 were introduced. 5% vol water vapor was introduced into the flue gas, and the acetone conversion efficiency of the catalyst in dry / wet flue gas was tested.
[0040] The formula for the catalytic efficiency of VOCs is: Where η represents the catalytic oxidation efficiency, C (in) It is the concentration (ppm) of the pollutants entering the reactor. C (out) It is the pollutant concentration (ppm) at the reactor outlet.
[0041] VOCs conversion efficiency results of the catalysts in Example 1 and Comparative Example 1: At 180°C, the VOCs conversion efficiency of (MnCeZrPrY)OO in dry flue gas was... v -F 0.1 The conversion rate of acetone was 92%; (MnCeZrPrY)OO in the wet flue gas v -F 0.1 The acetone conversion rate was 89%, and water vapor only reduced the catalyst activity by about 3%, indicating that the material has resistance to water poisoning.
[0042] The acetone conversion efficiency before and after F doping of the high-entropy oxide (MnCeZrPrY)O2 is as follows: Figure 3 As shown in the figure, the acetone conversion rate decreases only slightly after F doping. Furthermore, the difference between MnO2 in Comparative Example 2 and the F-doped MnO-O... v -F 0.1 The catalytic activity was tested, and the results are as follows: Figure 4 As shown, F doping leads to a significant decrease in the activity of the MnO2 catalyst (~50%, at 180°C). By comparing Comparative Example 2 with the catalyst of Example 1, it is demonstrated that the multi-component and single-phase structure characteristics of high-entropy catalysts can solve the problem of F poisoning of conventional metal oxides and achieve a balance between water resistance and activity in VOCs catalysis.
[0043] The extent to which high-entropy catalysts are affected by water vapor was assessed, and the results are as follows: Figure 5As shown, the undoped sample exhibited a 28% decrease in activity after introducing 5% water vapor into the flue gas, demonstrating a significant water poisoning effect. In contrast, the high-entropy oxides modified with different fluorine doping amounts showed a lower degree of activity decrease under the same conditions. The best effect was observed with a fluorine doping amount of 0.1 mol, reducing activity by only 3%, significantly improving water resistance. More importantly, long-term cycling experiments were conducted on the effects of water vapor on catalytic activity and stability before and after fluorine doping in Example 1 and Comparative Example 1. The results are as follows... Figure 6 As shown, when the water vapor is removed, the activity of the undoped catalyst in Comparative Example 1 cannot recover to its initial level, exhibiting typical irreversible deactivation characteristics. In contrast, the activity of the F-doped sample in Example 1 can be completely recovered, indicating that F doping effectively transforms the water poisoning process from irreversible to a reversible, dynamically regulated process. This result fully demonstrates that F doping in high-entropy systems can significantly enhance the catalyst's resistance to water poisoning and its long-term stability by constructing a low-polarity, self-healing surface environment.
[0044] Using high-entropy oxides with different F doping amounts as control examples, it is shown that F doping amounts within a certain range can balance catalyst activity and water resistance, achieving efficient removal of VOCs in wet flue gas.
[0045] The catalytic activity of high-entropy oxide catalysts with different F doping amounts in dry or wet flue gas was evaluated. The catalytic activity in dry flue gas was as follows: Figure 7 As shown, the catalytic activity in wet flue gas is as follows: Figure 8 As shown, Figure 7 The diagram shows the catalytic activity of high-entropy catalysts with different fluorine doping concentrations in dry flue gas. Under dry flue gas conditions, fluorine doping leads to a decrease in catalyst activity, and the decrease in activity is proportional to the amount of fluorine doping. For example, at 180°C, the catalytic activity decreases slightly when the doping concentration is low (0.05 mol), decreases by 7% when the doping concentration increases to 0.1 mol, and drops to 33% when the fluorine doping concentration is further increased to 1 mol. Figure 8 The diagram shows the catalytic activity of high-entropy catalysts with different fluorine doping levels in wet flue gas. Under wet flue gas conditions, fluorine doping improves the catalyst's resistance to water poisoning, and the higher the fluorine doping level, the stronger the catalyst's water resistance. Combined with... Figure 7 and Figure 8 Considering both the suppression of intrinsic catalyst activity by F doping and the enhancement of catalyst water resistance in wet flue gas, it is believed that the catalyst doped with 0.1 mol of F exhibits the best balance between activity and water resistance, making it the preferred F doping amount. When the F doping amount is 0.1 mol, the catalyst demonstrates the optimal balance between activity and water resistance.
[0046] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several modifications and improvements can be made without departing from the inventive concept, and these all fall within the protection scope of the present invention.
Claims
1. A method for preparing a fluorine-doped high-entropy oxide catalyst, characterized in that, include: (1) Manganese salt, cerium salt, praseodymium salt, zirconium salt, yttrium salt, glycine, and ammonium trifluoroacetate were dissolved together in deionized water and stirred at room temperature for 2-4 h to obtain a homogeneous precursor solution; (2) Place the precursor solution in a drying oven at 60-90℃ for 10-14 h to obtain a gel-like precursor; (3) The gel-like precursor was calcined at 500-700℃ for 20-40 minutes in air atmosphere, and then taken out and quenched at room temperature to obtain fluorine-doped high-entropy oxide catalyst.
2. The preparation method according to claim 1, characterized in that, The manganese salt, cerium salt, praseodymium salt, zirconium salt, and yttrium salt are all water-soluble salts.
3. The preparation method according to claim 2, characterized in that, The manganese salt is manganese nitrate, manganese acetate tetrahydrate, or manganese chloride tetrahydrate; the cerium salt is cerium nitrate hexahydrate, cerium(III) acetate hexahydrate, or cerium(III) chloride heptahydrate; the praseodymium salt is praseodymium nitrate hexahydrate, praseodymium(III) acetate hexahydrate, or praseodymium(III) chloride heptahydrate; the zirconium salt is zirconium nitrate pentahydrate, zirconium acetate, or zirconium chloride octahydrate; and the yttrium salt is yttrium nitrate hexahydrate, yttrium(III) acetate tetrahydrate, or yttrium chloride hexahydrate.
4. The preparation method according to claim 1, characterized in that, The molar ratio of metal ions in the manganese salt, cerium salt, praseodymium salt, zirconium salt, and yttrium salt is 1:1:1:1:
1.
5. The preparation method according to claim 1, characterized in that, In the precursor solution, the molar ratio of metal ions, glycine, and ammonium trifluoroacetate is 0.5-0.8:8-12:0.005-0.
02.
6. The preparation method according to claim 1, characterized in that, The gel-like precursor is placed in a quartz boat and then placed in a preheated tube furnace at 500-700℃.
7. A fluorine-doped high-entropy oxide catalyst obtained by the preparation method according to any one of claims 1-6, characterized in that, The general chemical formula is (MnCeZrPrY)OO. v -F, where F element partially replaces oxygen atoms, and oxygen vacancies O are present in the material. v .
8. The application of the fluorine-doped high-entropy oxide catalyst as described in claim 7 in the catalytic oxidation of VOCs.
9. The application according to claim 8, characterized in that, The catalyst was placed in the reactor, and 40 ppm acetone, 5 vol% O2 and carrier gas N2 were introduced. 5-10 vol% water vapor was introduced, the outlet concentration of acetone was monitored, and its removal efficiency was calculated.
10. The application according to claim 9, characterized in that, The temperature for the catalytic reaction is 150-200℃.