An iron-based multimetallic catalytic material, its preparation method and application
By constructing a multi-layered enclosed iron-based polymetallic oxide catalyst, the problems of structural instability and complex preparation of traditional iron-based catalysts were solved, achieving high efficiency and stability of the catalyst and physical isolation of active sites, simplifying the preparation process and reducing costs.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2026-03-06
- Publication Date
- 2026-05-26
AI Technical Summary
Traditional iron-based catalysts are structurally unstable, their active sites are prone to aggregation, and their catalytic performance decays rapidly. Furthermore, existing preparation methods are cumbersome, costly, and difficult to achieve the ordered arrangement and synergistic effect of multi-metal components.
By dissolving metal salts with different hydroxide solubility products in water, mixing them, and then reacting them with potassium ferrate to form a precipitate, followed by standing, filtration, washing, drying, and finally calcination at low temperature, a multi-layered enclosed iron-based polymetallic oxide catalyst is constructed to achieve a gradient distribution of metal components.
This approach achieves high efficiency and stability of the catalyst, as well as physical barrier of the active sites, extending its service life, simplifying the preparation process, reducing costs, and making it suitable for industrial applications.
Smart Images
Figure CN121797328B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of catalyst preparation technology, specifically relating to an iron-based multimetallic catalytic material, its preparation method, and its application. Background Technology
[0002] Reverse water gas reaction ( As a key reaction for achieving efficient conversion and utilization of carbon resources, the reaction has significant industrial application value in fields such as syngas production, carbon capture and conversion, and new energy storage. The efficiency and selectivity of this reaction largely depend on the performance of high-performance catalysts. Among them, iron-based catalysts have become a research hotspot for catalysts in the reverse-flow gas reaction due to their advantages such as low raw material cost, high catalytic activity, and good environmental compatibility.
[0003] However, traditional iron-based catalysts still have many shortcomings in practical applications: on the one hand, single iron-based catalysts have poor activity, their active sites are prone to aggregation, and their stability is poor. They are also prone to sintering or phase transformation during the reaction, leading to a rapid decline in catalytic performance. On the other hand, traditional iron-based catalysts have limited structural control capabilities, making it difficult to optimize reactant adsorption, intermediate conversion, and product desorption processes through precise structural design, thus restricting further improvements in catalytic activity and selectivity. Therefore, constructing iron-based polymetallic oxide catalysts with special structures through reasonable structural design and optimized preparation processes has become a key direction for improving the catalytic performance of countercurrent gas reaction.
[0004] In existing catalyst preparation technologies, structural control methods for metal oxide catalysts (such as impregnation, co-precipitation, and sol-gel methods) often fail to achieve the ordered arrangement and precise encapsulation of different metal components. Although some multi-metal catalysts have improved their performance through composite modification, the lack of clear structural guidance design results in uneven distribution of metal components, which fails to fully leverage the synergistic effect of each component. Furthermore, the preparation process often involves cumbersome steps, harsh reaction conditions, and high costs, which are not conducive to industrial applications.
[0005] Based on this, we developed a simple, mild, and precisely constructable method for preparing iron-based catalysts with enclosed structures to address the shortcomings of traditional countercurrent gas catalysts, such as structural instability, insufficient activity, and insufficient selectivity. This method has significant practical implications and application value when applied to countercurrent gas catalytic reactions. Summary of the Invention
[0006] This invention aims to overcome the shortcomings of existing iron-based catalysts, such as difficulty in structural control, easy aggregation of active sites, and insufficient catalytic stability and selectivity. It provides a simple, mild, and precisely constructable method for preparing iron-based polymetallic oxide catalysts with enclosed structures. Furthermore, this catalyst is applied to the reverse water gas catalytic reaction to improve reaction efficiency and stability, thus meeting the needs of industrial applications.
[0007] This invention is achieved through the following technical solution:
[0008] In a first aspect, the present invention provides a method for preparing an iron-based multimetallic catalytic material, specifically comprising the following steps:
[0009] Step 1: Dissolve two or more water-soluble metal salts with different solubility products in deionized water, and mix them by stirring or ultrasonic treatment to obtain mixed solution A;
[0010] Step 2: Dissolve potassium ferrate in cold deionized water to obtain solution B;
[0011] The molar amount of potassium ferrate is equal to the amount of hydroxide (OH) required to precipitate all the metal ions in step one. - Half the number of moles;
[0012] Step 3: Under stirring conditions, pour the solution B obtained in Step 2 into the mixed solution A obtained in Step 1 to obtain mixed solution C;
[0013] Step 4: The mixed solution C obtained in Step 3 is allowed to stand at a low temperature until a precipitate forms and the color of the supernatant changes from dark purple to light purple, while the pH of the supernatant is neutral; then it is filtered, washed and dried to obtain the catalyst precursor.
[0014] Step 5: The catalytic material precursor is calcined in a mixed atmosphere of hydrogen and argon, and then cooled to obtain the iron-based multimetallic catalytic material.
[0015] Furthermore, in step one, the total mass percentage concentration of the water-soluble metal salt in the mixed solution A is 1%-10%.
[0016] Furthermore, in step one, the metal elements in the water-soluble metal salt include at least two different metal elements other than iron, and the at least two different metal elements are selected from at least two of magnesium (Mg), copper (Cu), zinc (Zn), nickel (Ni), and cobalt (Co).
[0017] Furthermore, in step two, the temperature of the cold deionized water is 4-25℃.
[0018] Furthermore, in step four, the low-temperature environment is 2-10℃, and the drying temperature is 60-150℃.
[0019] Furthermore, in step five, the mixed atmosphere of hydrogen and argon is 5%-30% hydrogen by volume, the argon is in equilibrium, the calcination temperature is 300-600℃, and the calcination time is 2-4h.
[0020] In a second aspect, the present invention provides an iron-based multimetallic catalytic material prepared by the method described in the first aspect.
[0021] Furthermore, the catalytic material has a multi-layered enclosed microstructure, wherein metal oxides with relatively high hydroxide solubility products are distributed in the outer region of the structure, and metal oxides with relatively low hydroxide solubility products are distributed in the inner region of the structure.
[0022] Thirdly, the present invention also provides an application of iron-based polymetallic catalytic materials in catalytic reverse water gas reaction.
[0023] Compared with the prior art, the advantages of the present invention are as follows:
[0024] 1. Breakthrough in structural design: It breaks through the bottleneck of uneven component distribution in traditional multi-metal catalysts. By utilizing the difference in solubility product of different metal hydroxides, it precisely constructs an ordered enclosed structure with "high → low solubility product of hydroxide" corresponding to "outside → inside" of the structure, so as to achieve the gradient arrangement and synergistic effect of each metal component. Existing methods are difficult to achieve such precise structural control.
[0025] 2. The preparation process is more advantageous: it does not require harsh reaction conditions such as high temperature and high pressure, the steps are simple (only mixing, precipitation, post-treatment and calcination), and the operation is easy; moreover, the raw materials are common water-soluble metal salts and potassium ferrate, which are low in cost and have good environmental compatibility. It solves the problems of cumbersome steps, harsh conditions and high cost of existing preparation methods, and is more suitable for large-scale industrial production.
[0026] 3. The enclosed structure can effectively physically block active sites, inhibit agglomeration and sintering during the reaction process, avoid catalyst phase transformation, and greatly extend service life; while traditional metal oxide catalysts are prone to rapid catalytic performance decay due to unstable structure. Attached Figure Description
[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or parts are generally identified by similar reference numerals. In the drawings, the elements or parts are not necessarily drawn to scale.
[0028] Figure 1The images show the SEM images of the precursor of the MgCuFeO catalytic material prepared in Example 1 (a), the SEM image after the catalytic reaction (b), the STEM image (c), the three-dimensional structural schematic diagram of the corresponding material preparation process (d), and the elemental distribution line scan of the material (e).
[0029] Figure 2 This is a schematic diagram comparing the X-ray diffraction (XRD) spectra of the MgCuFeO catalytic material prepared in Example 1 and that in Comparative Example 2 after the catalytic reaction.
[0030] Figure 3 The images show the distribution mapping of elements (a), (b), (c), (d), (e), and (f) of the MgCuFeO catalytic material prepared in Example 1, obtained by scanning transmission electron microscopy (STEM).
[0031] Figure 4 The images shown are the scanning transmission electron microscope (STEM) images (a), HAADF images (b), Cu & Fe (c), Fe (d), Cu (e), and O element (f) distribution maps of Comparative Example 2.
[0032] Figure 5 The image shows a comparison of the catalytic activity of the MgCuFeO catalyst prepared in Example 1 and the catalysts prepared in Comparative Examples 1-3 in the countercurrent gas reaction.
[0033] Figure 6 The graph shows the long-term reaction stability test results of the MgCuFeO catalyst prepared in Example 1 at 500℃ and 600℃.
[0034] Figure 7 The graph shows the changes in the catalytic activity of a series of catalysts prepared by changing the ratio of Cu to Mg elements during synthesis in the counter-water gas reaction.
[0035] Figure 8 Transmission electron microscope image (a) and elemental distribution line scan (b) of the CoNiCuZnMgFeO catalyst prepared in Example 2;
[0036] Figure 9 This is a comparison of the catalytic activities of various iron-based encapsulated catalysts with different components prepared by the method of this invention in the countercurrent gas reaction under the same reaction conditions. Detailed Implementation
[0037] To clearly and completely describe the technical solution and its specific working process of the present invention, the specific embodiments of the present invention are as follows, in conjunction with the accompanying drawings:
[0038] Example 1
[0039] This embodiment provides a method for preparing the iron-based multimetallic catalytic material MgCuFeO, which specifically includes the following steps:
[0040] 1 mmol each of copper acetate and magnesium acetate were simultaneously dissolved in 30 ml of deionized water and magnetically stirred until completely dissolved, yielding a clear mixed solution A. 2 mmol of potassium ferrate was dissolved in 30 ml of pre-treated deionized water at 4°C to form solution B. While stirring, solution B was poured into mixed solution A, and stirring was continued for one minute to ensure homogeneity, yielding mixed solution C. Mixed solution C was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. A precipitate was observed to gradually form, and the color of the supernatant changed from dark purple to light purple. pH paper showed the supernatant to be neutral. The precipitate was filtered and washed several times alternately with deionized water and anhydrous ethanol. It was then transferred to an oven and dried at 80°C for 12 hours to obtain precursor powder. The dried precursor powder was placed in a quartz boat and placed in a tube furnace. A mixed gas (volume fraction: 20% H2 / 80%) was introduced at a flow rate of 50 mL / min. Under an Ar atmosphere, the temperature was increased to 500°C at a heating rate of 5°C / min and calcined at this temperature for 3 hours; then it was naturally cooled to room temperature under an inert atmosphere to obtain the catalyst material MgCuFeO.
[0041] Comparative Example 1
[0042] This comparative example provides a coprecipitation preparation method for the iron-based multimetallic catalytic material MgCuFeO, specifically including the following steps: 1 mmol each of copper acetate and magnesium acetate, and 2 mmol of ferric nitrate are dissolved in 30 ml of deionized water and magnetically stirred until completely dissolved to obtain a clear mixed solution A; 10 mmol of KOH is dissolved in 30 ml of deionized water to form solution B; under stirring, solution B is added dropwise to mixed solution A, and a precipitate is gradually observed to form; the precipitate is filtered and washed several times alternately with deionized water and anhydrous ethanol, transferred to an oven, and dried at 80 °C for 12 hours to obtain precursor powder; the dried precursor powder is placed in a quartz boat and placed in a tube furnace; under a mixed gas atmosphere (volume fraction: 20% H2 / 80% Ar) with a flow rate of 50 mL / min, the temperature is raised to 500 °C at a heating rate of 5 °C / min and calcined at this temperature for 3 hours; subsequently, it is naturally cooled to room temperature under an inert atmosphere to obtain MgCuFeO prepared by the coprecipitation method.
[0043] Comparative Example 2
[0044] This comparative example provides a method for preparing the iron-based multimetallic catalytic material CuFeO, specifically including the following steps: Dissolve 2 mmol of copper acetate in 30 ml of deionized water, and stir magnetically until completely dissolved to obtain a clear mixed solution A; dissolve 2 mmol of potassium ferrate in 30 ml of pre-treated deionized water at 4°C to form solution B; while stirring, pour solution B into mixed solution A, and continue stirring for one minute to ensure homogeneity, obtaining mixed solution C; transfer mixed solution C to a 4°C refrigerated environment and let it stand for 24 hours, during which a precipitate gradually forms, and the color of the supernatant changes from dark purple to light purple. pH paper tests show the supernatant is neutral; filter the precipitate and wash it several times alternately with deionized water and anhydrous ethanol, then transfer it to an oven and dry it at 80°C for 12 hours to obtain precursor powder; place the dried precursor powder in a quartz boat and place it in a tube furnace; saturate the furnace with a mixed gas (volume fraction: 20% H2 / 80%) at a flow rate of 50 mL / min. Under an Ar atmosphere, the temperature was increased to 500°C at a heating rate of 5°C / min and calcined at this temperature for 3 hours; then it was naturally cooled to room temperature under an inert atmosphere to obtain the catalyst CuFeO.
[0045] Comparative Example 3
[0046] This comparative example provides a method for preparing the iron-based multimetallic catalytic material MgFeO, specifically including the following steps: Dissolve 2 mmol of magnesium acetate in 30 ml of deionized water, and stir magnetically until completely dissolved to obtain a clear mixed solution A; dissolve 2 mmol of potassium ferrate in 30 ml of pre-treated deionized water at 4℃ to form solution B; while stirring, pour solution B into mixed solution A, and continue stirring for one minute to ensure homogeneity, obtaining mixed solution C; transfer mixed solution C to a 4℃ refrigerated environment and let it stand for 24 hours, during which a precipitate gradually forms, and the color of the supernatant changes from dark purple to light purple. pH paper tests show the supernatant is neutral; filter the precipitate and wash it several times alternately with deionized water and anhydrous ethanol, then transfer it to an oven and dry it at 80℃ for 12 hours to obtain precursor powder; place the dried precursor powder in a quartz boat and place it in a tube furnace; saturate the furnace with a mixed gas (volume fraction: 20% H2 / 80%) at a flow rate of 50 mL / min. Under an Ar atmosphere, the temperature was increased to 500°C at a heating rate of 5°C / min and calcined at this temperature for 3 hours; then it was naturally cooled to room temperature under an inert atmosphere to obtain the catalyst material MgFeO.
[0047] like Figure 1 As shown, the scanning transmission electron microscope (STEM) images and elemental distribution diagrams indicate that the catalytic material MgCuFeO prepared in Example 1 was obtained by calcining the MgFe / CuFe-LDH layered hydroxide precursor and exhibits a clear core-shell enclosed structure. Figure 3 The elemental mapping diagram further confirms that the signal distribution regions of Mg and Fe elements (MgFeO framework) constitute the main framework of the structure, while the Cu element signal is concentrated in a specific region inside the framework (CuO particles), forming a typical enclosed configuration of CuO encapsulated by MgFeO.
[0048] Figure 2 The XRD pattern showed that CuO's characteristic crystalline peaks were still detectable in the reacted MgCuFeO catalyst, indicating that the surrounding structure effectively stabilized Cu and prevented its excessive agglomeration during the reaction. In contrast, the CuFeO catalyst prepared without Mg (Comparative Example 2) did not exhibit this stabilizing effect.
[0049] like Figure 4 The image shows CuFeO prepared by removing Mg from Comparative Example 2. Elemental mapping indicates that Cu precipitates from the bulk phase in the unenclosed structure; this is because the Mg-O bond is a strong ionic bond with high lattice energy and an extremely high bond energy (~394 kJ / mol). At the RWGS reaction temperature, Mg-O is almost not reduced by H2, providing a robust and irreducible physical support structure under thermodynamic inertness. In the catalytic structure prepared without introducing Mg, the catalyst consists only of the Cu-O and Fe-O systems. Under an H2 reaction atmosphere, CuO is rapidly reduced to highly mobile Cu. 0 Atoms / nanoparticles. Fe2O3 is also partially reduced and reconstructed, and its structure itself is in a dynamic state of change. Not only can it not fix Cu, but it may also precipitate Cu species due to lattice changes.
[0050] The catalytic activity of the catalysts prepared in Example 1 and Comparative Examples 1-3 was investigated using a fixed-bed reactor. 50 mg of catalyst was weighed and mixed thoroughly with 250 mg of quartz sand, then loaded into a quartz tube. A CO2:H2 molar ratio of 1:1 was used. The reaction was carried out at atmospheric pressure between 200-600 °C, with a gas space velocity (GHSV) of 48,000 ml·g. -1 ·h -1 Up to 9,000,000 ml·g -1 ·h -1 The product was analyzed using a Shimadzu GC-2014C online gas chromatograph, equipped with a TCD and flame ionization detector, and high-purity argon was used as the carrier gas.
[0051] like Figure 5As shown, the MgCuFeO catalytic material prepared in Example 1 and the control samples of Comparative Examples 1-3 (with Mg or Cu elements removed) exhibited excellent catalytic activity against water gas at a carbon-to-hydrogen ratio of 1:1 and a feed space velocity of 48,000 ml / min. The MgCuFeO reached the equilibrium reaction rate at 350 °C, which was significantly better than the control samples (with Mg or Cu components removed).
[0052] like Figure 6 As shown, long-term stability tests were conducted at 500℃ and 600℃ for approximately 100 hours, respectively. The activity of the MgCuFeO catalytic material prepared in Example 1 did not show significant attenuation, demonstrating its excellent thermal stability.
[0053] like Figure 7 As shown, by adjusting the feeding ratio of copper acetate to magnesium acetate (Cu:Mg) during synthesis, it was found that the catalytic activity of the prepared catalyst reached its optimum when Cu:Mg = 1:1 (molar ratio), indicating that the distribution ratio of each component has an important influence on the performance.
[0054] Example 2
[0055] This embodiment provides a method for preparing the iron-based multimetallic catalytic material CoNiCuZnMgFeO, which specifically includes the following steps:
[0056] 0.5 mmol each of copper acetate, magnesium acetate, zinc acetate, nickel acetate, and cobalt acetate were simultaneously dissolved in 30 ml of deionized water to form mixed solution A; 2.5 mmol of potassium ferrate was dissolved in 30 ml of pre-treated deionized water at 4°C to form solution B; the subsequent steps were exactly the same as in Example 1: solution B was poured into mixed solution A while stirring, and after stirring for one minute, the solution was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. After precipitate formed and the supernatant changed from dark purple to light purple and became neutral, the solution was filtered, washed, and dried to obtain the precursor. The precursor was calcined at 500°C under a 20% H₂ / Ar equilibrium atmosphere to obtain the catalyst CoNiCuZnMgFeO.
[0057] Figure 8 The images show the transmission and line scan elemental analysis spectra of CoNiCuZnMgFeO synthesized in Example 2. As can be seen from the images, the obtained catalytic material also forms a uniform and dense enclosed structure. All the incorporated metal elements show a gradient distribution at the microscale, indicating that the preparation method of the present invention has good universality for multi-metal systems and can achieve the controllable assembly of complex components.
[0058] Example 3
[0059] This embodiment provides a method for preparing the iron-based multimetallic catalytic material CoMoCuZnMgFeO, which specifically includes the following steps:
[0060] 0.5 mmol each of copper acetate, magnesium acetate, zinc acetate, ammonium molybdate, and cobalt acetate were simultaneously dissolved in 30 ml of deionized water to form mixed solution A; 2.5 mmol of potassium ferrate was dissolved in 30 ml of pre-treated deionized water at 4°C to form solution B; the subsequent steps were exactly the same as in Example 1: solution B was poured into mixed solution A while stirring, and after stirring for one minute, the solution was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. After precipitate formed and the supernatant changed from dark purple to light purple and became neutral, the solution was filtered, washed, and dried to obtain the precursor. The precursor was calcined at 500°C under a 20% H₂ / Ar equilibrium atmosphere to obtain the catalyst CoMoCuZnMgFeO.
[0061] Example 4
[0062] This embodiment provides a method for preparing the iron-based multimetallic catalytic material CoNiCuZnFeO, which specifically includes the following steps:
[0063] 0.5 mmol each of copper acetate, zinc acetate, nickel acetate, and cobalt acetate were simultaneously dissolved in 30 ml of deionized water to form mixed solution A; 2 mmol of potassium ferrate was dissolved in 30 ml of pre-treated deionized water at 4°C to form solution B; the subsequent steps were exactly the same as in Example 1: solution B was poured into mixed solution A while stirring, and after stirring for one minute, the solution was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. After precipitate formed and the supernatant changed from dark purple to light purple and became neutral, it was filtered, washed, and dried to obtain the precursor. The precursor was calcined at 500°C under a 20% H2 / Ar equilibrium atmosphere to obtain the catalyst CoNiCuZnFeO.
[0064] Example 5
[0065] This embodiment provides a method for preparing the iron-based multimetallic catalytic material NdSmCuCoMgFeO, which specifically includes the following steps:
[0066] 0.5 mmol each of neodymium acetate, copper acetate, samarium acetate, magnesium acetate, and cobalt acetate were simultaneously dissolved in 30 ml of deionized water to form mixed solution A; 2.5 mmol of potassium ferrate was dissolved in 30 ml of deionized water pre-treated at 4°C to form solution B; the subsequent steps were exactly the same as in Example 1: solution B was poured into mixed solution A while stirring, and after stirring for one minute, the solution was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. After precipitate formed and the supernatant changed from dark purple to light purple and became neutral, the solution was filtered, washed, and dried to obtain the precursor. The precursor was calcined at 500°C under a 20% H2 / Ar equilibrium atmosphere to obtain the catalyst NdSmCuCoMgFeO.
[0067] Example 6
[0068] This embodiment provides a method for preparing the iron-based multimetallic catalytic material CoNiCuZnCsFeO, which specifically includes the following steps:
[0069] 0.5 mmol each of zinc acetate, copper acetate, nickel acetate, cesium acetate, and cobalt acetate were simultaneously dissolved in 30 ml of deionized water to form mixed solution A; 2.5 mmol of potassium ferrate was dissolved in 30 ml of pre-treated deionized water at 4°C to form solution B; the subsequent steps were exactly the same as in Example 1: solution B was poured into mixed solution A while stirring, and after stirring for one minute, the solution was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. After precipitate formed and the supernatant changed from dark purple to light purple and became neutral, the solution was filtered, washed, and dried to obtain the precursor. The precursor was calcined at 500°C under a 20% H₂ / Ar equilibrium atmosphere to obtain the catalyst CoNiCuZnCsFeO.
[0070] Example 7
[0071] This embodiment provides a method for preparing the iron-based multimetallic catalytic material 0.5%PtMgCuFeO, which specifically includes the following steps:
[0072] 1 mmol each of copper acetate and magnesium acetate, and 0.72 ml of 10 mM platinum nitrate solution were simultaneously dissolved in 30 ml of deionized water to form mixed solution A; 2 mmol of potassium ferrate was dissolved in 30 ml of pre-treated deionized water at 4°C to form solution B; the subsequent steps were exactly the same as in Example 1: solution B was poured into mixed solution A while stirring, and after stirring for one minute, the solution was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. After precipitate formed and the supernatant changed from dark purple to light purple and became neutral, the solution was filtered, washed, and dried to obtain the precursor. The precursor was calcined at 500°C under a 20% H2 / Ar equilibrium atmosphere to obtain the catalyst material 0.5% PtMgCuFeO.
[0073] Example 8
[0074] This embodiment provides a method for preparing the iron-based multimetallic catalytic material CaCuFeO, which specifically includes the following steps:
[0075] 1 mmol each of copper acetate and calcium acetate were dissolved in 30 ml of deionized water to form mixed solution A; 2 mmol of potassium ferrate was dissolved in 30 ml of pre-treated deionized water at 4°C to form solution B; the subsequent steps were exactly the same as in Example 1: solution B was poured into mixed solution A while stirring, and after stirring for one minute, the solution was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. After precipitate formed and the supernatant changed from dark purple to light purple and became neutral, the solution was filtered, washed, and dried to obtain the precursor. The precursor was calcined at 500°C under a 20% H₂ / Ar equilibrium atmosphere to obtain the catalyst CaCuFeO.
[0076] Example 9
[0077] This embodiment provides a method for preparing the iron-based multimetallic catalytic material NiMgFeO, which specifically includes the following steps:
[0078] 1 mmol each of nickel acetate and magnesium acetate were dissolved in 30 ml of deionized water to form mixed solution A; 2 mmol of potassium ferrate was dissolved in 30 ml of deionized water pre-treated at 4°C to form solution B; the subsequent steps were exactly the same as in Example 1: solution B was poured into mixed solution A while stirring, and after stirring for one minute, the solution was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. After precipitate formed and the supernatant changed from dark purple to light purple and became neutral, the solution was filtered, washed, and dried to obtain the precursor. The precursor was calcined at 500°C under a 20% H₂ / Ar equilibrium atmosphere to obtain the catalyst NiMgFeO.
[0079] Example 10
[0080] This embodiment provides a method for preparing the iron-based multimetallic catalytic material CoMgFeO, which specifically includes the following steps:
[0081] 1 mmol each of cobalt acetate and magnesium acetate were dissolved in 30 ml of deionized water to form mixed solution A; 2 mmol of potassium ferrate was dissolved in 30 ml of deionized water pre-treated at 4°C to form solution B; the subsequent steps were exactly the same as in Example 1: solution B was poured into mixed solution A while stirring, and after stirring for one minute, the solution was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. After precipitate formed and the supernatant changed from dark purple to light purple and became neutral, it was filtered, washed, and dried to obtain the precursor. The precursor was calcined at 500°C under a 20% H2 / Ar equilibrium atmosphere to obtain the catalyst CoMgFeO.
[0082] Example 11
[0083] This embodiment provides a method for preparing the iron-based multimetallic catalytic material ZnMgFeO, which specifically includes the following steps:
[0084] 1 mmol each of zinc acetate and magnesium acetate were dissolved in 30 ml of deionized water to form mixed solution A; 2 mmol of potassium ferrate was dissolved in 30 ml of pre-treated deionized water at 4°C to form solution B; the subsequent steps were exactly the same as in Example 1: solution B was poured into mixed solution A while stirring, and after stirring for one minute, the solution was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. After a precipitate formed and the supernatant changed from dark purple to light purple and became neutral, it was filtered, washed, and dried to obtain the precursor. The precursor was calcined at 500°C under a 20% H₂ / Ar equilibrium atmosphere to obtain the catalyst ZnMgFeO.
[0085] Example 12
[0086] This embodiment provides a method for preparing the iron-based multimetallic catalytic material NdMgCuFeO, which specifically includes the following steps:
[0087] 0.5 mmol each of neodymium acetate, magnesium acetate, and copper acetate were dissolved in 30 ml of deionized water to form mixed solution A; 1.5 mmol of potassium ferrate was dissolved in 30 ml of pre-treated deionized water at 4°C to form solution B; the subsequent steps were exactly the same as in Example 1: solution B was poured into mixed solution A while stirring, and after stirring for one minute, the solution was transferred to a 4°C refrigerated environment and allowed to stand for 24 hours. After precipitate formed and the supernatant changed from dark purple to light purple and became neutral, the solution was filtered, washed, and dried to obtain the precursor. The precursor was calcined at 500°C under a 20% H₂ / Ar equilibrium atmosphere to obtain the catalyst NdMgCuFeO.
[0088] Figure 9 The catalytic activity of the synthesized CoNiCuZnMgFeO and the materials prepared in Examples 2-12 at 300°C with a carbon-to-hydrogen ratio of 1:1 and a feed space velocity of 48,000 ml / min was measured. All catalysts exhibited considerable CO2 conversion capacity, fully demonstrating the broad applicability and effectiveness of the preparation method described in this invention in constructing high-performance reverse water-gas shift reaction catalysts.
[0089] The preferred embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.
[0090] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.
[0091] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.
Claims
1. A method for preparing an iron-based multimetallic catalytic material, characterized in that, Includes the following steps: Step 1: Dissolve two or more water-soluble metal salts with different solubility products in deionized water, and mix them by stirring or ultrasonic treatment to obtain mixed solution A; Step 2: Dissolve potassium ferrate in cold deionized water to obtain solution B; The amount of potassium ferrate is equal to half the amount of hydroxide ions required for the precipitation of all metal ions in step one. Step 3: Under stirring conditions, pour the solution B obtained in Step 2 into the mixed solution A obtained in Step 1 to obtain mixed solution C; Step 4: The mixed solution C obtained in Step 3 is allowed to stand at a low temperature until a precipitate forms and the color of the supernatant changes from dark purple to light purple, while the pH of the supernatant is neutral; then it is filtered, washed, and dried to obtain the catalyst precursor. Step 5: The catalytic material precursor is calcined in a mixed atmosphere of hydrogen and argon, and then cooled to obtain the iron-based multimetallic catalytic material; In step one, the metal elements in the water-soluble metal salt include at least two different metal elements other than iron, and the at least two different metal elements are selected from at least two of magnesium, copper, zinc, nickel, and cobalt; and the at least two different metal elements are not magnesium and zinc. In step two, the temperature of the cold deionized water is 4-25℃; The low-temperature environment is 2-10℃; The calcination temperature is 300-600℃.
2. The method for preparing an iron-based multimetallic catalytic material as described in claim 1, characterized in that, In step one, the total mass percentage concentration of the water-soluble metal salt in the mixed solution A is 1%-10%.
3. The method for preparing an iron-based multimetallic catalytic material as described in claim 1, characterized in that, In step four, the drying temperature is 60-150℃.
4. The preparation method of an iron-based multimetallic catalytic material as described in claim 1, characterized in that, In step five, the mixed atmosphere of hydrogen and argon is 5%-30% hydrogen by volume, the argon is balanced, and the calcination time is 2-4 hours.
5. An iron-based multimetallic catalytic material, characterized in that, It is prepared by the preparation method according to any one of claims 1-4.
6. The iron-based multimetallic catalytic material as described in claim 5, characterized in that, The iron-based multimetallic catalytic material has a multilayered enclosed microstructure, wherein metal oxides with relatively high hydroxide solubility products are distributed in the outer region of the structure, and metal oxides with relatively low hydroxide solubility products are distributed in the inner region of the structure.
7. The application of the iron-based multimetallic catalytic material as described in claim 5 in the catalytic reaction of countercurrent water gas.