A ternary heterogeneous catalyst carrier and its preparation method and application

Abstract

The present invention discloses a ternary heterogeneous catalyst carrier and its preparation method and application, belonging to the field of material preparation and catalysis technology. In the present invention, cheap and easily available molybdenum source, iron source and sugar carbon source are fully mixed through two simple operations of dissolution and evaporation to obtain a calcined precursor, and the Fe3Mo3N@Fe3Mo3C ternary heterogeneous carrier is directly obtained by a one-step calcination method in an inert atmosphere. The reaction raw materials of the present invention are all low-priced and easily available bulk chemicals; the preparation operations are all safe and simple conventional basic operations, such as dissolution, stirring, drying, grinding, calcination, etc., without high-pressure reaction operations; inert carrier gas is used during the high-temperature calcination process, and there is no flammable and explosive gas such as hydrogen and methane, and the calcination process is safe and reliable. The above technical advantages can ensure that the present invention can achieve safe, low-cost, easy-to-operate and repeatable industrial production, and can be applied to the fields of electrocatalysis and thermal catalysis that require higher anti-sintering stability and selectivity.

Description

Technical Field

[0001] The present invention belongs to the technical field of material preparation and catalysis, and particularly relates to a ternary heterogeneous catalyst carrier and a preparation method and application thereof. Background Art

[0002] Multimetallic compounds have excellent catalytic activity and have been widely used in the field of catalysis. Fe3Mo3N@Fe3Mo3C, as an important member of multimetallic compounds, has been widely used as a metal-loaded heterogeneous carrier in related fields such as electrocatalysis and thermal catalysis. It can significantly improve the anti-sintering stability and selectivity of the catalyst during the catalytic process.

[0003] There are two main existing methods for synthesizing Fe3Mo3N@Fe3Mo3C. One method uses carbon nanotubes as a carbon source, uniformly mixes them with metal salts and ammonium molybdate, and then calcines them in an inert atmosphere to produce Fe3Mo3N@Fe3Mo3C (e.g., CN109351359A). However, this invention is limited in that carbon nanotubes are less common than polysaccharides and are expensive, even exceeding the price of the heterogeneous support they are made from. This high production cost limits its industrial application. The second method is to fully mix cetyltrimethylammonium bromide (CTAB), chitosan aqueous solution, FeCl2, and ammonium heptamolybdate, and then hydrothermally treat them in a sealed polytetrafluoroethylene-lined stainless steel autoclave. The hydrothermally treated product is placed in a tubular furnace in a flowing atmosphere of H2 to obtain Fe3Mo3N@Fe3Mo3C (such as Robust Fe3Mo3C Supported IrMn Clusters as Highly EfficientBifunctional Air Electrode for Metal–Air Battery). This method also involves the relatively expensive cetyltrimethylammonium bromide (CTAB), and the preparation process requires a high-temperature and high-pressure hydrothermal reaction followed by calcination in a hydrogen atmosphere. The operation steps are complex and the safety is poor, making it difficult to apply in industrial production. Summary of the Invention

[0004] In order to overcome the defects of the above-mentioned prior art, the purpose of the present invention is to provide a ternary heterogeneous catalyst carrier and its preparation method and application, which are low-cost, simple to operate, mild reaction conditions, safe and pollution-free; when used as a catalyst carrier, it can effectively improve the anti-sintering stability and selectivity.

[0005] The present invention is achieved through the following technical solutions:

[0006] The present invention discloses a method for preparing a ternary heterogeneous catalyst carrier, comprising the following steps:

[0007] Step 1: Dissolve an iron source, a molybdenum source, and a sugar carbon source in water at a molar ratio of (1-10):1:(10-100), stir, and evaporate to dryness to obtain a black solid precursor;

[0008] Step 2: The black solid precursor obtained in step 1 is calcined at high temperature under an inert carrier gas atmosphere to obtain a Fe3Mo3N@Fe3Mo3C ternary heterogeneous catalyst support.

[0009] Preferably, in step 1, the water is deionized water.

[0010] Preferably, in step 1, the iron source is one or more of ferric nitrite, ferric sulfate, ferric chloride, and ferrous chloride.

[0011] Preferably, in step 1, the molybdenum source is one or more of ammonium molybdate and sodium molybdate.

[0012] Preferably, in step 1, the carbohydrate carbon source is glucose, maltose or sucrose.

[0013] Preferably, in step 2, the inert carrier gas is nitrogen or argon.

[0014] Preferably, in step 2, the calcination temperature is 400-1500° C., and the calcination time is 1-12 hours.

[0015] Preferably, in step 2, calcination is carried out in a tubular furnace.

[0016] The invention also discloses a ternary heterogeneous catalyst carrier prepared by the preparation method.

[0017] The present invention also discloses the application of the ternary heterogeneous catalyst carrier as a catalyst carrier in thermal catalysis and electrocatalysis reactions.

[0018] Compared with the prior art, the present invention has the following beneficial technical effects:

[0019] The preparation method of the ternary heterogeneous catalyst carrier of the present invention uses a carbohydrate compound as a carbon source instead of expensive carbon nanotubes. The reaction can adjust the ratio of Fe3Mo3N and Fe3Mo3C in the Fe3Mo3N@Fe3Mo3C heterogeneous carrier by the excess degree of the carbon source. The preparation process does not require a high-pressure hydrothermal reaction operation, reducing the number of steps in preparing materials and the coefficient of experimental risk. The Fe3Mo3N@Fe3Mo3C heterogeneous carrier is prepared by preparing a precursor of a molybdenum salt and an iron salt in a water bath with a molybdenum salt, an iron salt, and a carbohydrate organic compound. The precursor of the molybdenum salt and the iron salt is then directly calcined and complexed in situ to obtain the Fe3Mo3N@Fe3Mo3C heterogeneous carrier. The heterogeneous carrier is prepared based on the theory of strong and weak carrier interactions. Catalysts with strong carrier interactions will undergo Ostwald ripening during the catalytic process, thereby destroying the active structure of the catalyst and greatly reducing the activity of the catalyst. Catalysts with weak carrier interactions will undergo particle aggregation and migration during the catalytic process, destroying the active structure of the catalyst and greatly reducing the activity of the catalyst. Catalysts with strong carrier interactions have a good inhibitory effect on particle aggregation and migration, while catalysts with weak carrier interactions have an inhibitory effect on Ostwald ripening. Therefore, the preparation of a heterogeneous carrier with two types of interactions has a very strong inhibitory effect on Ostwald ripening and particle aggregation and migration, two sintering modes involved in the use of the catalyst. At the same time, the reaction raw materials of the present invention are all low-priced and easily available bulk chemicals; the preparation operations are all safe and simple conventional basic operations, such as dissolution, stirring, drying, grinding, calcination, etc., without high-pressure reaction operations; inert carrier gas is used during the high-temperature calcination process, and there is no flammable and explosive gas such as hydrogen and methane, so the calcination process is safe and reliable.

[0020] Furthermore, the iron source is one or more of ferric nitrite, ferric sulfate, ferric chloride, and ferrous chloride, and the molybdenum source is one or more of ammonium molybdate and sodium molybdate, which are inexpensive and readily available.

[0021] In the ternary heterogeneous catalyst support prepared using the aforementioned preparation method, the metal atoms M can be atomically dispersed on the support surface via carbon bridges within the Fe3Mo3N@Fe3Mo3C heterogeneous support. These metal atoms, M, can form M-C bonds on the carbide surface. These M-C bonds effectively and stably separate the M sites within the Fe3Mo3N@Fe3Mo3C heterogeneous support, providing a maximum active site density and high structural stability. Furthermore, the synergistic catalytic process between M and Fe3Mo3N@Fe3Mo3C provides a highly active interface structure. The efficient C-H bond dissociation and CO reforming capabilities of the atomically dispersed M atoms are key to its excellent thermocatalytic performance. Furthermore, the mesoporous structure of the Fe3Mo3N@Fe3Mo3C heterogeneous support significantly improves battery cycling stability, providing a promising alternative for use as an air cathode in alkaline electrolytes. Consequently, the Fe3Mo3N@Fe3Mo3C heterogeneous support exhibits excellent corrosion resistance, electrical conductivity, and sintering stability, making it suitable for use as a metal-loaded heterogeneous support in a wide range of applications, including electrocatalysis and thermocatalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a process flow chart of the present invention;

[0023] Figure 2 This is the XRD characterization diagram of the Fe3Mo3N@Fe3Mo3C heterogeneous support prepared in the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments, which are intended to explain the present invention rather than to limit it.

[0025] like Figure 1 The present invention adopts a molybdenum source, an iron source and a carbon source to be fully mixed by dissolving and evaporating in two simple steps to obtain a calcined precursor, and adopts an inert atmosphere one-step calcination method to directly obtain the Fe3Mo3N@Fe3Mo3C ternary heterogeneous carrier.

[0026] Example 1

[0027] A mixed solution of ferric nitrite, ammonium molybdate, and glucose in a molar ratio of 1:1:10 was prepared in a beaker and stirred with a glass rod to fully dissolve. The solution turned light yellow and was then placed in a constant-temperature magnetic stirrer at 90°C and stirred for 2 hours before evaporating to dryness. A white precipitate formed during the process. The evaporated sample was transferred to a drying oven and dried for 12 hours. After removal, it was placed in a mortar and ground into a fine powder to facilitate calcination. The sample was then placed in a quartz crucible and transferred to a tube furnace. The temperature was increased to 400°C at a rate of 5°C / min and calcined in a nitrogen atmosphere for 1 hour to obtain the Fe3Mo3N@Fe3Mo3C heterogeneous carrier.

[0028] Example 2

[0029] A mixed solution of ferric chloride, ammonium molybdate, sodium molybdate, and maltose in a molar ratio of 4:1:40 was prepared in a beaker and stirred with a glass rod to fully dissolve. The solution turned light yellow and was then placed in a constant-temperature magnetic stirrer at 90°C and stirred for 2 hours before evaporating to dryness. A white precipitate formed during the process. The evaporated sample was transferred to a drying oven and dried for 12 hours. After removal, it was placed in a mortar and ground into a fine powder to facilitate calcination. The sample was then placed in a quartz crucible and transferred to a tube furnace. The temperature was raised to 700°C at a heating rate of 5°C / min and calcined in a nitrogen atmosphere for 4 hours to obtain the Fe3Mo3N@Fe3Mo3C heterogeneous support.

[0030] Example 3

[0031] A mixed solution of ferric sulfate, sodium molybdate, ammonium molybdate, and maltose in a molar ratio of 7:1:70 was prepared in a beaker and stirred with a glass rod to fully dissolve. The solution turned light yellow and was then placed in a constant-temperature magnetic stirrer at 90°C and stirred for 2 hours before evaporating to dryness. A white precipitate formed during the process. The evaporated sample was transferred to a drying oven and dried for 12 hours. After removal, it was placed in a mortar and ground into a fine powder to facilitate calcination. The sample was then placed in a quartz crucible and transferred to a tube furnace. The temperature was increased to 900°C at a heating rate of 5°C / min and calcined in a nitrogen atmosphere for 9 hours to obtain the Fe3Mo3N@Fe3Mo3C heterogeneous carrier.

[0032] Example 4

[0033] A mixed solution of ferric chloride and ferric sulfate, ammonium molybdate, and sucrose in a molar ratio of 8:1:80 was prepared in a beaker and stirred with a glass rod to fully dissolve. The solution turned light yellow and was then placed in a constant-temperature magnetic stirrer at 90°C and stirred for 2 hours before evaporating to dryness. A white precipitate formed during the process. The evaporated sample was transferred to a drying oven and dried for 12 hours. After removal, it was placed in a mortar and ground into a fine powder to facilitate calcination. The sample was then placed in a quartz crucible and transferred to a tube furnace. The temperature was increased to 1000°C at a rate of 5°C / min and calcined in an argon atmosphere for 10 hours to obtain the Fe3Mo3N@Fe3Mo3C heterogeneous support.

[0034] Example 5

[0035] A mixed solution of ferrous chloride, ferric sulfate, sodium molybdate, ammonium molybdate, and glucose in a molar ratio of 9:1:90 was prepared in a beaker and stirred with a glass rod to fully dissolve. The solution turned light yellow and was then placed in a constant-temperature magnetic stirrer at 90°C and stirred for 2 hours before evaporating to dryness. A white precipitate formed during the process. The evaporated sample was transferred to a drying oven and dried for 12 hours. After removal, it was placed in a mortar and ground into a fine powder to facilitate calcination. The sample was then placed in a quartz crucible and transferred to a tube furnace. The temperature was increased to 1250°C at a rate of 5°C / min and calcined in a nitrogen atmosphere for 11 hours to obtain the Fe3Mo3N@Fe3Mo3C heterogeneous carrier.

[0036] Figure 2 The XRD pattern of the Fe3Mo3N@Fe3Mo3C heterogeneous support of the present invention shows obvious characteristic diffraction peaks of Fe3Mo3N@Fe3Mo3C. Strong diffraction peaks of Fe3Mo3C (PDF#47-1191) are observed at 2θ = 22.6°, 32.2°, 35.2°, 39.7°, 42.2°, 46.1°, 49.1°, 54.7°, 59.2°, 64.2°, 67.2°, 69.0°, 71.9°, 73.7°, 74.2°, 78.2°, and 78.7°. Fe3Mo3N (PDF#48-1408) shows strong diffraction peaks at 2θ=22.7°, 26.7°, 32.3°, 35.3°, 39.8°, 42.4°, 46.3°, 49.4°, 55.0°, 59.5°, 64.6°, 67.6°, 72.3°, 74.1°, 78.9°, and 79.1° in the figure, so it can be judged that the product is a Fe3Mo3N@Fe3Mo3C heterogeneous support.

[0037] Table 1 shows the hydrogen production performance, CO selectivity, and catalytic material stability of the Fe3Mo3N@Fe3Mo3C heterogeneous supports prepared in various examples of the present invention in thermal catalytic applications. It can be seen that the Fe3Mo3N@Fe3Mo3C heterogeneous support prepared in Example 1, using a molar ratio of ferric nitrite, ammonium molybdate, and glucose of 1:1:10, a calcination temperature of 400°C, and a calcination time of 1 hour, exhibits the best hydrogen production performance, CO selectivity, and catalytic material stability, reaching 111.8 μmol H2 / g / s, 1.3%, and 1000 h, respectively.

[0038] Table 1 Thermocatalytic performance of Fe3Mo3N@Fe3Mo3C heterogeneous supports

[0039]

[0040] Table 2 shows the detection limit and sensitivity of the Fe3Mo3N@Fe3Mo3C heterogeneous support prepared in various embodiments of the present invention as an electrode material in electrocatalysis. It can be seen that when the conditions adopted in Example 1 are a molar ratio of ferric nitrite, ammonium molybdate and glucose of 1:1:10, a calcination temperature of 400°C and a calcination time of 1 h, the Fe3Mo3N@Fe3Mo3C heterogeneous support prepared has the lowest detection limit and the highest sensitivity, which are 50 nM and 256.6 μA / mMcm respectively. 2 .

[0041] Table 2 Electrocatalytic performance of Fe3Mo3N@Fe3Mo3C heterogeneous supports

[0042]

[0043] It should be noted that the above is only part of the embodiments of the present invention. Equivalent changes made to the system described in the present invention are all included in the scope of protection of the present invention. Those skilled in the art of the present invention may make similar substitutions for the specific examples described, as long as they do not deviate from the structure of the present invention or exceed the scope defined by the claims, and all such substitutions are within the scope of protection of the present invention.

Claims

1. A method for preparing a ternary heterogeneous catalyst carrier, characterized in that: The following steps are involved: Step 1: Dissolve ferric nitrite, ammonium molybdate, and glucose in water at a molar ratio of 1:1:10, stir, and evaporate to dryness to obtain a black solid precursor; Step 2: The black solid precursor obtained in step 1 is calcined at a high temperature under an inert carrier gas atmosphere to obtain a Fe3Mo3N@Fe3Mo3C ternary heterogeneous catalyst support. The calcination temperature is 400°C and the calcination time is 1 hour.

2. The method for preparing a ternary heterogeneous catalyst carrier according to claim 1, characterized in that: In step 1, the water is deionized water.

3. The method for preparing a ternary heterogeneous catalyst carrier according to claim 1, characterized in that: In step 2, the inert carrier gas is nitrogen or argon.

4. The method for preparing a ternary heterogeneous catalyst carrier according to claim 1, characterized in that: In step 2, calcination is carried out in a tube furnace.

5. A ternary heterogeneous catalyst carrier prepared according to the preparation method according to any one of claims 1 to 4.

6. Use of the ternary heterogeneous catalyst carrier according to claim 5 as a catalyst carrier in thermal catalysis and electrocatalysis reactions.

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