Method for preparing FeNb2S4

Abstract

The invention discloses a method for preparing FeNb2S4, which comprises the following steps: uniformly mixing niobium trichloride and ferrous sulfide in a protective atmosphere to obtain a mixture, then putting the mixture into a reaction kettle, and adjusting the reaction kettle to be in a protective atmosphere or a vacuum condition for high-temperature reaction to obtain FeNb2S4 after the reaction. According to the method disclosed by the invention, the FeNb2S4 is prepared by taking niobium trichloride as a raw material, one-step preparation is realized, and the process method is high in operability, simple in process, low in requirement on preparation equipment and easy to industrially popularize and apply.

Description

Technical Field

[0001] The invention belongs to the technical field of electrocatalysis and relates to a method for preparing FeNb2S4, and in particular to a method for preparing FeNb2S4 by using niobium trichloride. Background Art

[0002] FeNb2S4 is a highly efficient electrocatalyst that can be used for electrocatalytic synthesis of ammonia. At present, the main method for preparing this material is to prepare niobium and iron into niobium-iron alloy, and then convert the zero-valent niobium and iron into FeNb2S4 through a sulfidation process. Chinese patent document CN 113930789 A discloses a new type of iron-niobium-based ultrafine nanoparticle catalyst used for electrocatalytic synthesis of ammonia. The iron source and niobium source are mixed and freeze-dried to form an iron-niobium aerogel, and then the aerogel is ignited to obtain iron-niobium oxide, and then sulfided to obtain FeNb2S4 ultrafine nanoparticles. In this application document, high-valent iron and niobium are reduced to prepare FeNb2S4. The current existing method for preparing FeNb2S4 requires the process of preparing an intermediate product first and then sulfiding, which has problems such as cumbersome operation and long production cycle. Chinese patent document CN119372492A discloses a method for separating niobium from niobium-containing ore, wherein a niobium crude concentrate is mixed with a sulfiding agent to obtain a mixture, and the mixture is then subjected to reduction smelting to obtain a reduced ore, and a niobium-rich product is obtained directly from the reduced ore, or the niobium-rich product is obtained after post-processing the reduced ore. A sulfiding agent and a reducing agent are required in the preparation process and the calcination temperature is relatively high. Summary of the invention

[0003] In order to overcome the problems in the prior art, the present invention provides a method for preparing FeNb2S4, which uses niobium trichloride as a raw material to prepare FeNb2S4 in one step. The process method has strong operability and simple process, and does not require the use of reducing agents and sulfurizing agents.

[0004] In order to solve the above technical problems, the technical solution proposed by the present invention is: The present invention provides a method for preparing FeNb2S4, comprising the following steps: The niobium trichloride and ferrous sulfide are uniformly mixed under a protective atmosphere to obtain a mixture, and then the mixture is put into a reactor, and the reactor is adjusted to perform a high-temperature reaction under a protective atmosphere or vacuum conditions to obtain FeNb2S4 after the reaction.

[0005] In the present invention, niobium trichloride and ferrous sulfide are used for high-temperature reaction. The technical idea is to directly prepare FeNb2S4 by a one-step method. The valence states of niobium and iron do not change. This is different from the idea of ​​preparing FeNb2S4 by sulfiding niobium-iron alloy from a zero-valent state in the prior art. There is no need for a reduction reaction, and FeNb2S4 with the same valence state can be obtained by a one-step reaction.

[0006] As an optional embodiment, in the method provided by the present invention, the protective atmosphere is one or both of argon or nitrogen.

[0007] As an optional embodiment, in the method provided by the present invention, the molar mass ratio of niobium trichloride to ferrous sulfide is 1:2-4.

[0008] As an optional embodiment, in the method provided by the present invention, the temperature of the high-temperature reaction under the protective atmosphere is 700-950° C., and the reaction time is greater than 30 min.

[0009] In the present invention, since there is no need to reduce iron and niobium, the raw materials will be vaporized at 700-950° C. in the reactor and react to generate FeNb2S4 without the need for a higher temperature.

[0010] As an optional implementation, in the method provided by the present invention, the vacuum degree is less than or equal to 0.01 Pa.

[0011] As an optional embodiment, in the method provided by the present invention, the iron sulfide is selected from one or more of ferrous sulfide, ferrous trisulfide, pyrrhotite, pyrrhotite, pyrite, and ferrous disulfide.

[0012] As an optional embodiment, in the method provided by the present invention, niobium trichloride and ferrous sulfide are mixed to form a preform, and then subjected to a high temperature reaction.

[0013] As an optional embodiment, in the method provided by the present invention, the preform is prepared by granulation or tableting.

[0014] In the present invention, making a preform is beneficial to improving the reaction efficiency.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a method for preparing FeNb2S4 by using niobium trichloride. Compared with the two-step method for preparing FeNb2S4, the present invention can prepare FeNb2S4 by using niobium trichloride as a raw material in one step. In the present invention, FeNb2S4 can be prepared without using a sulfiding agent and a reducing agent. 4， The process method has strong operability, simple process, low requirements on preparation equipment, and is easy to promote and apply industrially. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0017] Figure 1 XRD spectrum of FeNb2S4 prepared in Example 1; Figure 2 The unit cell diagram of FeNb2S4 prepared in Example 1; Figure 3 This is the EDS spectrum of FeNb2S4 prepared in Example 1; Figure 4 XRD spectrum of FeNb2S4 prepared in Example 2; Figure 5 This is the EDS spectrum of FeNb2S4 prepared in Example 2; Figure 6 This is the EDS spectrum of FeNb2S4 prepared in Example 3; Figure 7 This is the EDS spectrum of FeNb2S4 prepared in Example 4; Figure 8 This is the EDS spectrum of FeNb2S4 prepared in Example 5; Fig. 9 This is the EDS spectrum of FeNb2S4 prepared in Example 6. DETAILED DESCRIPTION

[0018] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0019] Unless otherwise defined, all professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0020] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0021] Example 1 A method for preparing FeNb2S4 comprises the following steps: firstly, niobium trichloride NbCl3 and FeS are uniformly mixed in an argon atmosphere at a molar mass ratio of 1:2, and then pressed into a crucible. After the crucible is placed in a reactor, the atmosphere in the reactor is adjusted to argon, and then the temperature is raised to 700°C and maintained for 60 minutes to terminate the reaction.

[0022] After cooling, the FeNb2S4 material in flake form can be directly selected from the reaction product. The FeNb2S4 material is subjected to single crystal XRD diffraction analysis, and the results are as follows: Figure 1 As shown. After analysis, the crystal cell structure of FeNb2S4 material is as follows Figure 2 As shown in Figure 2, the crystal system of FeNb2S4 material is hexagonal. At the same time, the EDS spectrum obtained by energy spectrometer test is as follows: Figure 3 As shown, the main characteristic elements are niobium, iron and sulfur.

[0023] Example 2 A method for preparing FeNb2S4, firstly, niobium trichloride NbCl3 and iron trisulfide are uniformly mixed in an argon atmosphere at a molar mass of 1:2, granulated, and then put into a crucible, after the crucible is put into a reactor, the atmosphere in the reactor is adjusted to argon, and then the temperature is raised to 950°C and maintained for 30 minutes, and the reaction is completed.

[0024] After cooling, the FeNb2S4 material can be directly selected from the reaction product. The FeNb2S4 material is analyzed by XRD, and the diffraction spectrum is as follows: Figure 4 As shown, the phase is FeNb2S4; at the same time, the EDS spectrum obtained by the energy spectrometer test is as follows Figure 5 As shown, the main characteristic elements are niobium, iron and sulfur.

[0025] Example 3 A method for preparing FeNb2S4 comprises the following steps: firstly, niobium trichloride NbCl3 and FeS are uniformly mixed in a molar mass ratio of 1:4 under an argon atmosphere and then put into a crucible; after the crucible is put into a reactor, the atmosphere in the reactor is adjusted to argon; then, the temperature is raised to 800°C and maintained for 60 minutes, and the reaction is completed.

[0026] After cooling, the FeNb2S4 material in sheet form can be directly selected from the reaction product. The FeNb2S4 material is tested by an energy spectrometer, and the obtained EDS spectrum is as follows: Figure 6 As shown, the main characteristic elements are niobium, iron and sulfur.

[0027] Example 4 A method for preparing FeNb2S4, firstly, niobium trichloride NbCl3 and FeS are uniformly mixed and granulated in a nitrogen atmosphere according to a molar mass of 1:3, and then put into a crucible, after the crucible is put into a reactor, the reactor is evacuated to a vacuum degree of 0.01 Pa, and then the temperature is raised to 900°C and maintained for 30 minutes, and the reaction is completed.

[0028] After cooling, the FeNb2S4 material in sheet form can be directly selected from the reaction product. The FeNb2S4 material is tested by an energy spectrometer, and the obtained EDS spectrum is as follows: Figure 7 As shown, the main characteristic elements are niobium, iron and sulfur.

[0029] Example 5 A method for preparing FeNb2S4, firstly, niobium trichloride NbCl3 and ferrous disulfide are uniformly mixed and granulated in a nitrogen atmosphere according to a molar mass of 1:2, and then put into a crucible, after the crucible is put into a reactor, the reactor is evacuated to a vacuum degree of 0.01 Pa, and then the temperature is raised to 700°C and maintained for 30 minutes, and the reaction is completed.

[0030] After cooling, the FeNb2S4 material in sheet form can be directly selected from the reaction product. The FeNb2S4 material is tested by an energy spectrometer, and the obtained EDS spectrum is as follows: Figure 8 As shown, the main characteristic elements are niobium, iron and sulfur.

[0031] Example 6 A method for preparing FeNb2S4, firstly, niobium trichloride NbCl3 and FeS are uniformly mixed and granulated in a nitrogen atmosphere according to a molar mass of 1:4, and then put into a crucible, after the crucible is put into a reactor, the reactor is evacuated to a vacuum degree of 0.01 Pa, and then the temperature is raised to 800°C and maintained for 60 minutes, and the reaction is completed.

[0032] After cooling, the FeNb2S4 material in sheet form can be directly selected from the reaction product. The FeNb2S4 material is tested by an energy spectrometer, and the obtained EDS spectrum is as follows: Fig. 9 As shown, the main characteristic elements are niobium, iron and sulfur.

[0033] Comparative Example 1 The difference from Example 1 is that the reaction was carried out under air atmosphere and the other conditions were the same as those in Example 1. No flaky FeNb2S4 was found in the reaction product.

[0034] Comparative Example 2 The difference from Example 1 is that the molar mass ratio of niobium trichloride NbCl3 to FeS is 1:5, and the other conditions are the same as those in Example 1. Flake FeNb2S4 is found in the reaction product, and the reaction product contains more impurities.

[0035] Comparative Example 3 The difference from Example 4 is that the molar mass ratio of niobium trichloride NbCl3 to FeS is 1:1, and the other conditions are the same as those in Example 4. A small amount of flaky FeNb2S4 is found in the reaction product, and there are many impurities in the reaction product.

[0036] Comparative Example 4 A method for preparing FeNb2S4, firstly, Nb2O5, ferrous sulfide and coke are uniformly mixed in a mass ratio of 1:0.4:0.2 under an argon atmosphere, granulated, and then put into a crucible, and after the crucible is put into a reactor, the atmosphere in the reactor is adjusted to argon, and then the temperature is raised to 950°C, maintained for 30 minutes, and the reaction is terminated. After detection, no FeNb2S4 is formed in the reaction product.

[0037] The above contents are further detailed descriptions of the present invention in combination with specific preferred embodiments, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the field to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A method for preparing FeNb2S4, characterized in that: The following steps are involved: The niobium trichloride and ferrous sulfide are uniformly mixed under a protective atmosphere to obtain a mixture, and then the mixture is put into a reactor, and the reactor is adjusted to perform a high-temperature reaction under a protective atmosphere or vacuum conditions to obtain FeNb2S4 after the reaction.

2. The method for preparing FeNb2S4 according to claim 1, characterized in that: The protective atmosphere is one or both of argon and nitrogen.

3. The method for preparing FeNb2S4 according to claim 1, characterized in that: The molar mass ratio of the niobium trichloride to ferrous sulfide is 1:2-4.

4. The method for preparing FeNb2S4 according to claim 1, characterized in that: The temperature of the high temperature reaction under the protective atmosphere is 700-950° C., and the reaction time is greater than 30 minutes.

5. The method for preparing FeNb2S4 according to claim 1, characterized in that: The vacuum degree is less than or equal to 0.01Pa.

6. The method for preparing FeNb2S4 according to claim 1, characterized in that: Niobium trichloride and ferrous sulfide are mixed to form a preform, which is then subjected to a high temperature reaction.

7. The method for preparing FeNb2S4 according to claim 6, characterized in that: The preform is prepared by granulation or tableting.

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