Preparation method of iron-doped cerium nickelate
By using a metal-organic framework as a precursor, an iron-doped cerium nickelate catalyst was prepared, which solved the problem of insufficient catalytic performance of perovskite catalysts in the prior art and achieved improved catalytic performance and PMS activation efficiency.
Patent Information
- Application Number
- CN202511000191.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-07-21
- Publication Date
- 2025-11-07
AI Technical Summary
Existing technologies struggle to improve the catalytic performance of perovskite catalysts and the efficiency of PMS activation through synthetic strategies without compromising the structural integrity of the perovskite.
Using metal-organic frameworks (MOFs) as precursors, iron-doped cerium nickelate catalysts were prepared by reacting a mixed solution of cerium salts, iron salts, imidazoles, and potassium nickel cyanide. High-temperature calcination was then used to form an ordered crystal structure to improve catalytic performance.
It effectively increases the specific surface area of the catalyst, improves catalytic performance, achieves efficient PMS activation, and obtains an ordered crystal structure without the use of surfactants.
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Figure CN120900643A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of inorganic functional materials, and particularly relates to a cerium nickelate doped with iron as well as a preparation method and application thereof. BACKGROUND
[0002] Advanced oxidation processes (AOPs) have attracted extensive attention due to their high degradation efficiency, environmental sustainability and wide applicability, and among them, peroxymonosulfate (PMS) activation is one of the most effective methods for removing organic pollutants. The core problem is a high-efficiency and stable catalyst. Among numerous materials, perovskite materials have become a hot material for transition metal-activated PMS to remove pollutants due to their excellent structural stability and excellent catalytic performance. In a typical ABO3 perovskite (such as cerium nickelate, CeNiO3), the A site is occupied by rare earth Ce ions, and the B site is occupied by transition metal nickel ions. Among them, the B-site transition metal ions play a key role in determining the catalytic performance of the material. By doping a second metal in the B site, the physical, chemical and catalytic properties of the perovskite can be precisely adjusted without affecting the integrity of the perovskite structure. Therefore, it is of great research significance to prepare a perovskite-type catalyst doped with high-efficiency and stable transition metal ions.
[0003] Among various synthesis methods, the synthesis strategy using metal organic frameworks (MOFs) as precursors can synthesize perovskite-type catalysts with high porosity and specific surface area, thereby greatly increasing the number of active sites and accelerating the activation efficiency of PMS. Therefore, it is a very challenging task to synthesize doped perovskite-type high-efficiency peroxymonosulfate (PMS) activation catalysts using metal organic frameworks as precursors. SUMMARY
[0004] Therefore, in order to solve the above technical problems, the application provides a cerium nickelate doped with iron as well as a preparation method and application thereof, which comprises the following steps: Step 1, dissolving cerium salt and iron salt in an ethanol aqueous solution in sequence to form an ethanol aqueous solution containing cerium salt and iron salt; Step 2, under stirring, adding imidazole to the solution obtained in step 1, and then adding potassium nickel cyanide aqueous solution drop by drop; Step 3, reacting the solution obtained in step 2 at a certain temperature and standing to obtain cerium-nickel precursor precipitate, washing the cerium-nickel precursor precipitate with deionized water for three times, and drying to obtain a cerium-nickel precursor; Step 4, placing the cerium-nickel precursor obtained in step 3 in a crucible, calcining with a muffle furnace, and obtaining the cerium nickelate doped with iron after natural cooling.
[0005] Further, the concentration of the cerium salt in step 1 is 0.02-0.05 mol / L, the molar ratio of the cerium salt to the iron salt is 1:0.05-1:0.2, and the concentration of the aqueous ethanol solution is 80% (v / v).
[0006] Further, the cerium salt in step 1 is one of cerium nitrate, cerium acetate or cerium sulfate, and the iron salt is one of ferric chloride, ferric nitrate or ferric sulfate.
[0007] Further, the molar ratio of the cerium salt to the imidazole in step 2 is 1:0.8-1:2.2, and the molar ratio of the cerium salt to potassium nickelocyanide (II) is 1:1-1:2.0.
[0008] Further, the stirring speed in step 2 is 180-220 r / min.
[0009] Further, the reaction temperature in step 3 is 55-70 ℃.
[0010] Further, the drying temperature in step 3 is 60-80 ℃.
[0011] Further, the calcination temperature in step 4 is 550-700 ℃, the calcination time is 1-5 hours, and the heating rate of the calcination is 1-3 ℃ / min.
[0012] The application further discloses an iron-doped cerium nickelate catalyst prepared by the preparation method.
[0013] Compared with the prior art, the application can obtain the following technical effects: 1) The synthesis strategy of taking a metal organic framework (MOF) as a precursor effectively increases the specific surface area of the catalyst and improves the catalytic performance.
[0014] 2) The ordered crystal can be obtained without adding a surfactant in the reaction system.
[0015] 3) The catalytic performance of the iron-doped cerium nickelate is greatly improved compared with the undoped cerium nickelate.
[0016] Of course, it is not necessary for any product implementing the application to achieve all the technical effects described above. DETAILED DESCRIPTION
[0017] The drawings described herein are used to provide further understanding of the application, and form a part of the application. The schematic embodiments of the application and the description thereof are used to explain the application, and do not constitute an improper limitation on the application. In the drawings: Figure 1 is a scanning electron microscope photo of the iron-doped cerium nickelate of the application; Figure 2 is an XRD spectrum of the undoped cerium nickelate and the cerium nickelate with different iron doping amounts of the application.
[0018] Figure 3 Figure is a tetracycline removal rate chart of the undoped cerium nickelate and iron-doped cerium nickelate catalysts of the present application DETAILED DESCRIPTION
[0019] The embodiments of the present application will be described in detail below with the accompanying drawings and examples, so that the implementation process of how the present application applies technical means to solve technical problems and achieves technical effects can be fully understood and implemented.
[0020] The present application provides a preparation method of iron-doped cerium nickelate, comprising the following steps: Step 1, dissolve cerium salt and iron salt in ethanol aqueous solution in sequence to form an ethanol aqueous solution containing cerium salt and iron salt; the cerium salt is one of cerium nitrate, cerium acetate or cerium sulfate, and the iron salt is one of ferric chloride, ferric nitrate or ferric sulfate; the concentration of cerium salt is 0.02-0.05 mol / L, the molar ratio of cerium salt to iron salt is 1:0.05-1:0.2, and the concentration of ethanol aqueous solution is 80% (v / v).
[0021] Step 2, under stirring, add imidazole to the solution obtained in step 1, and then add potassium nickel cyanide aqueous solution drop by drop; the molar ratio of cerium salt to imidazole is 1:0.8-1:2.2, and the molar ratio of cerium salt to potassium nickel cyanide is 1:1-1:2.0; the stirring speed is 180-220 r / min.
[0022] Step 3, react the solution obtained in step 2 at a certain temperature and stand to obtain cerium-nickel precursor precipitate, wash with deionized water for three times, and dry to obtain cerium-nickel precursor; the reaction temperature is 55-70 ℃, and the drying temperature is 60-80 ℃.
[0023] Step 4, place the cerium-nickel precursor obtained in step 3 in a crucible, calcine with a muffle furnace, and naturally cool to obtain iron-doped cerium nickelate. The calcination temperature is 550-700 ℃, the calcination time is 1-5 hours, and the heating rate of calcination is 1-3 ℃ / min.
[0024] In the present preparation method, 1, potassium nickel cyanide can directly react with cerium ions to generate a cerium-nickel metal organic framework precursor, and by adding iron ions in the reaction system, an iron-containing cerium-nickel metal organic framework precursor can be obtained, and the iron-doped cerium nickelate catalyst can be obtained by high-temperature conversion of the precursor. The cerium-nickel metal organic framework contains a large amount of carbon-containing ligands, which generates a large amount of pore structure in the high-temperature treatment process, which is beneficial to improve the specific surface area and catalytic performance of the catalyst, and the iron doping further changes the crystal structure and bonding mode of the cerium nickelate catalyst, further improving its catalytic performance.
[0025] 2. The nitrogen atom in the imidazole molecule can coordinate with cerium and iron ions, altering the crystal growth rate and nucleation mode of the system, generating an ordered cerium-nickel metal-organic framework precursor. This precursor, after high-temperature conversion, yields an iron-doped cerium nickelate catalyst. Furthermore, the unique molecular structure of imidazole acts as a buffer in solution, stabilizing the pH of the reaction system and preventing side reactions such as hydrolysis of metal ions.
[0026] 3. The reaction system uses a mixture of ethanol and water as the solvent, which can change the polarity of the solution system and the formation rate of the metal-organic framework, thereby ensuring the quality of the cerium-nickel metal-organic framework precursor crystals.
[0027] Comparative Example Cerium nitrate was dissolved in an ethanol-water solution (80%, v / v) under stirring to obtain an ethanol-water solution containing 0.02 mol / L cerium nitrate. Under stirring, a certain amount of imidazole was added to the above solution at a stirring speed of 180 r / min, with a molar ratio of cerium nitrate to imidazole of 1:1. Then, potassium nickel cyanide aqueous solution was added dropwise, with a molar ratio of cerium nitrate to potassium nickel cyanide of 1:1. The mixture was stirred at 60 °C. After the reaction was complete, the mixture was allowed to stand to obtain a cerium-nickel precursor precipitate, which was washed three times with deionized water and dried to obtain the cerium-nickel precursor. The cerium-nickel precursor was placed in a crucible and calcined in a muffle furnace at 650 °C for 1 hour at a heating rate of 2 °C / min. After natural cooling, an undoped cerium nickelate sample was obtained. The XRD pattern of the obtained product is shown below. Figure 2 As shown, the performance of activated PMS in degrading tetracycline is as follows: Figure 3 As shown.
[0028] Example 1 1. Cerium nitrate and ferric nitrate were sequentially dissolved in an ethanol-water solution (80%, v / v) to obtain an ethanol-water solution containing 0.02 mol / L cerium nitrate and 0.002 mol / L ferric nitrate. Under stirring conditions, a certain amount of imidazole was added to the above solution at a rotation speed of 180 r / min, with a molar ratio of cerium nitrate to imidazole of 1:1. Then, potassium nickel cyanide aqueous solution was added dropwise, with a molar ratio of cerium nitrate to potassium nickel cyanide of 1:1. The above mixed solution was stirred at 60 °C. After the reaction was completed, the mixture was allowed to stand to obtain a cerium-nickel precursor precipitate. This precipitate was washed three times with deionized water and dried to obtain a light red cerium-nickel precursor. The cerium-nickel precursor was placed in a crucible and calcined in a muffle furnace at a temperature of 650 °C for 1 hour at a heating rate of 2 °C / min. After natural cooling, iron-doped cerium nickelate was obtained. The scanning electron microscope image of the obtained product is shown below. Figure 1 As shown, the obtained sample is a sheet-like structure assembled from nanoparticles. The XRD pattern of the obtained product is shown below. Figure 2As shown, the obtained iron-doped cerium nickelate with a cerium-iron molar ratio of 1:0.1 has a crystal structure consistent with that of undoped cerium nickelate, and all diffraction peak positions are the same as those of the standard card CeNiO3 (mp-776207), indicating the successful preparation of the perovskite-type iron-doped cerium nickelate. The performance of the prepared iron-doped cerium nickelate catalyst in activating PMS to degrade tetracycline is as follows Figure 3 As shown, under normal temperature and pressure conditions, the degradation rate of tetracycline is as high as 90% after 60 minutes of reaction, which is much higher than that of the undoped iron-doped cerium nickelate sample obtained in the comparative example.
[0029] Example 2 Cerium nitrate and iron nitrate were sequentially dissolved in an ethanol aqueous solution (80%, v / v) to obtain an ethanol aqueous solution containing 0.02 mol / L cerium nitrate and 0.001 mol / L iron chloride; under stirring conditions, a certain amount of imidazole was added to the above solution, the stirring speed was 200 r / min, and the molar ratio of cerium nitrate to imidazole was 1:0.8; then, potassium nickel cyanide aqueous solution was added dropwise, and the molar ratio of cerium nitrate to potassium nickel cyanide was 1:1.2; the above mixed solution was continuously stirred at 60 ℃, and after the reaction was completed, cerium-nickel precursor precipitate was obtained by standing, which was washed with deionized water three times and dried to obtain a cerium-nickel precursor; the cerium-nickel precursor was placed in a crucible and calcined in a muffle furnace, the calcination temperature was 600 ℃, the calcination time was 2 hours, the heating rate of calcination was 2 ℃ / min, and iron-doped cerium nickelate was obtained after natural cooling.
[0030] Example 3 Cerium acetate and iron nitrate were sequentially dissolved in an ethanol aqueous solution (80%, v / v) to obtain an ethanol aqueous solution containing 0.02 mol / L cerium acetate and 0.004 mol / L iron nitrate; under stirring conditions, a certain amount of imidazole was added to the above solution, the stirring speed was 180 r / min, and the molar ratio of cerium acetate to imidazole was 1:1.2; then, potassium nickel cyanide(II) aqueous solution was added dropwise, and the molar ratio of cerium acetate to potassium nickel cyanide was 1:2; the above mixed solution was continuously stirred at 60 ℃, and after the reaction was completed, cerium-nickel precursor precipitate was obtained by standing, which was washed with deionized water three times and dried to obtain a cerium-nickel precursor; the cerium-nickel precursor was placed in a crucible and calcined in a muffle furnace, the calcination temperature was 650 ℃, the calcination time was 2 hours, the heating rate of calcination was 1 ℃ / min, and iron-doped cerium nickelate was obtained after natural cooling.
[0031] Example 4 Dissolve cerium sulfate and ferric nitrate in an ethanol aqueous solution (80%, v / v) in sequence to obtain an ethanol aqueous solution containing 0.02 mol / L cerium sulfate and 0.003 mol / L ferric sulfate; under stirring, a certain amount of imidazole is added to the above solution, the rotating speed is 220 r / min, and the molar ratio of cerium sulfate to imidazole is 1:1.1; then, a potassium nickel cyanide aqueous solution is added drop by drop, and the molar ratio of cerium sulfate to potassium nickel cyanide is 1:1.5; continue to stir the above mixed solution at 60 ℃, and after the reaction is completed, the cerium-nickel precursor precipitate is obtained by standing, and is washed with deionized water for three times and dried to obtain the cerium-nickel precursor; the cerium-nickel precursor is placed in a crucible and calcined by using a muffle furnace, the calcination temperature is 700 ℃, the calcination time is 3 hours, the heating rate of calcination is 2 ℃ / min, and the iron-doped cerium nickelate is obtained after natural cooling.
[0032] The iron-doped cerium nickelate can be used for the advanced oxidation catalytic degradation of tetracycline antibiotic wastewater, and the efficiency of degrading water pollutants is effectively improved after iron doping, so that the iron-doped cerium nickelate has a wide application prospect.
[0033] As some terms are used in the description and claims to refer to particular components or methods, those skilled in the art will understand that different terms can be used in different regions to refer to the same component. The description and claims of the present application do not distinguish components by the difference in name. As mentioned throughout the description and claims, "comprising" is an open term, and should be interpreted as "including but not limited to". "Substantially" means within an acceptable error range, and those skilled in the art can solve the technical problems within a certain error range, and basically achieve the technical effects. The subsequent description in the specification is a preferred embodiment for implementing the present application, and the description is for the purpose of illustrating the general principles of the present application, and is not intended to limit the scope of the present application. The protection scope of the present application is defined by the appended claims.
[0034] It should also be noted that the terms "comprise", "contain" or any other variant thereof are intended to cover non-exclusive inclusion, so that the goods or systems comprising a series of elements not only include those elements, but also include other elements not explicitly listed, or include elements inherent to such goods or systems. Without more limitations, the element defined by the sentence "comprising a" does not exclude the existence of other identical elements in the goods or systems comprising the element.
[0035] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, it is to be understood that the present invention is not limited to the precise embodiments described herein, and that right can be made to various other embodiments and insulations, modifications, and equivalents thereof without departing from the spirit and scope of the present invention. Accordingly, the application is not to be considered as limited to the precise embodiments described herein, but appropriate modifications and / or alterations given or otherwise provided can be made thereto by those with ordinary skill in the art without departing from the spirit and scope of the present invention which is limited only by the claims appended hereto.
Claims
1. A method for preparing iron-doped cerium nickelate, characterized in that, The method comprises the following steps: Step 1, dissolving the cerium salt and the iron salt in an ethanol aqueous solution in sequence to form an ethanol aqueous solution containing the cerium salt and the iron salt; Step 2, under stirring, adding imidazole into the solution obtained in step 1, and then adding potassium nickel cyanide aqueous solution drop by drop; Step 3, reacting the solution obtained in step 2 at a certain temperature and standing to obtain cerium-nickel precursor precipitate, washing the cerium-nickel precursor precipitate with deionized water for three times, and drying to obtain cerium-nickel precursor; Step 4, placing the cerium-nickel precursor obtained in step 3 in a crucible, calcining with a muffle furnace, and obtaining iron-doped cerium nickelate after natural cooling.
2. The method for preparing iron-doped cerium nickelate according to claim 1, characterized in that, The concentration of the cerium salt in step 1 is 0.02-0.05 mol / L, the molar ratio of the cerium salt to the iron salt is 1:0.05-1:0.2, and the concentration of the ethanol aqueous solution is 80% (v / v).
3. The preparation method according to claim 1, characterized in that, The cerium salt in step 1 is one of cerium nitrate, cerium acetate or cerium sulfate, and the iron salt is one of ferric chloride, ferric nitrate or ferric sulfate.
4. The method for preparing iron-doped cerium nickelate according to claim 1, characterized in that, The molar ratio of the cerium salt to imidazole in step 2 is 1:0.8-1:2.2, and the molar ratio of the cerium salt to potassium nickel cyanide is 1:1-1:2.
0.
5. The method for preparing iron-doped cerium nickelate according to claim 1, characterized in that, The stirring speed in step 2 is 180-220 r / min.
6. The method for preparing iron-doped cerium nickelate according to claim 1, characterized in that, The reaction temperature in step 3 is 55-70 ℃.
7. The method for preparing iron-doped cerium nickelate according to claim 1, characterized in that, The drying temperature in step 3 is 60-80 ℃.
8. The method for preparing iron-doped cerium nickelate according to claim 1, characterized in that, The calcination temperature in step 4 is 550-700 ℃, the calcination time is 1-5 hours, and the heating rate of calcination is 1-3 ℃ / min.