A method for preparing FeNb2S4

Abstract

The present invention discloses a method for preparing FeNb2S4. The method comprises uniformly mixing niobium trichloride and ferrous sulfide under a protective atmosphere to obtain a mixture, then placing the mixture in a reactor and adjusting the reactor to a protective atmosphere or vacuum conditions for a high-temperature reaction to obtain FeNb2S4. The method of the present invention uses niobium trichloride as a raw material to prepare FeNb2S4 in a one-step process. The process is highly operable, simple, and has low requirements for preparation equipment, making it easy to promote and apply industrially.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalysis and relates to a method for preparing FeNb2S4, 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 ammonia synthesis. Currently, the main method for preparing this material is to prepare niobium and iron into a niobium-iron alloy, and then convert the zero-valent niobium and iron into FeNb2S4 through a sulfurization process. Chinese patent document CN 113930789 A discloses a new iron-niobium-based ultrafine nanoparticle catalyst for electrocatalytic ammonia synthesis. The iron source and niobium source are mixed and freeze-dried to form an iron-niobium aerogel. This aerogel is then ignited to obtain iron-niobium oxide, which is then sulfurized to obtain FeNb2S4 ultrafine nanoparticles. In this application document, the high-valent iron and niobium are reduced to prepare FeNb2S4. The current method for preparing FeNb2S4 requires the preparation of an intermediate product followed by sulfurization, which has problems such as cumbersome operation and a long production cycle. Chinese patent document CN119372492A discloses a method for separating niobium from niobium-containing ore. The method comprises mixing a crude niobium concentrate with a sulfiding agent to obtain a mixture, and then reducing and smelting the mixture to obtain a reduced ore. A niobium-rich product is obtained directly from the reduced ore, or the reduced ore is post-processed to obtain the niobium-rich product. The preparation process requires the use of a sulfiding agent and a reducing agent, 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 raw material to prepare FeNb2S4 in one step. The process is highly operable, simple, 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:

[0005] The present invention provides a method for preparing FeNb2S4, comprising the following steps:

[0006] Niobium trichloride and ferrous sulfide are mixed uniformly under a protective atmosphere to obtain a mixture, and then the mixture is placed in a reactor, and the reactor is adjusted to be under a protective atmosphere or vacuum conditions for high-temperature reaction to obtain FeNb2S4.

[0007] In the present invention, niobium trichloride and ferrous sulfide are used for high-temperature reaction. The technical idea is to directly prepare FeNb2S4 using 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 in a one-step reaction.

[0008] As an optional embodiment, in the method provided by the present invention, the protective atmosphere is one or both of argon and nitrogen.

[0009] 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.

[0010] 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 minutes.

[0011] 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.

[0012] As an optional embodiment, in the method provided by the present invention, the vacuum degree is less than or equal to 0.01 Pa.

[0013] 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.

[0014] 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.

[0015] As an optional embodiment, in the method provided by the present invention, the preform is prepared by granulation or tableting.

[0016] In the present invention, making a preform is beneficial to improving the reaction efficiency.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] 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

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0020] Figure 1 XRD spectrum of FeNb2S4 prepared in Example 1;

[0021] Figure 2 This is a unit cell diagram of FeNb2S4 prepared in Example 1;

[0022] Figure 3 This is the EDS spectrum of FeNb2S4 prepared in Example 1;

[0023] Figure 4 XRD spectrum of FeNb2S4 prepared in Example 2;

[0024] Figure 5 This is the EDS spectrum of FeNb2S4 prepared in Example 2;

[0025] Figure 6 This is the EDS spectrum of FeNb2S4 prepared in Example 3;

[0026] Figure 7 This is the EDS spectrum of FeNb2S4 prepared in Example 4;

[0027] Figure 8 This is the EDS spectrum of FeNb2S4 prepared in Example 5;

[0028] Figure 9 This is the EDS spectrum of FeNb2S4 prepared in Example 6. DETAILED DESCRIPTION

[0029] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with the accompanying drawings and preferred embodiments. However, the protection scope of the present invention is not limited to the following specific embodiments.

[0030] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical 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.

[0031] 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.

[0032] Example 1

[0033] A method for preparing FeNb2S4 comprises: first, uniformly mixing niobium trichloride (NbCl3) and FeS in a molar mass ratio of 1:2 under an argon atmosphere; then, forming tablets into pellets and placing them in a crucible; placing the crucible in a reactor; adjusting the atmosphere in the reactor to argon; and then heating the reactor to 700°C and maintaining the mixture for 60 minutes to complete the reaction.

[0034] After cooling, the FeNb2S4 material 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 unit cell structure of FeNb2S4 material is as follows Figure 2 As shown, 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.

[0035] Example 2

[0036] A method for preparing FeNb2S4 comprises: first, uniformly mixing niobium trichloride (NbCl3) and iron trisulfide (FeS4) in a molar mass ratio of 1:2 under an argon atmosphere, granulating the mixture, and then placing the mixture into a crucible. After placing the crucible 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 to terminate the reaction.

[0037] 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.

[0038] Example 3

[0039] A method for preparing FeNb2S4 comprises: first, uniformly mixing niobium trichloride (NbCl3) and FeS in a molar ratio of 1:4 under an argon atmosphere, and then placing the mixture in a crucible; placing the crucible in a reactor; adjusting the atmosphere in the reactor to argon; and then heating the reactor to 800°C and maintaining the mixture for 60 minutes to terminate the reaction.

[0040] After cooling, the FeNb2S4 material can be directly selected from the reaction product. The FeNb2S4 material is tested by an energy dispersive spectrometer, and the obtained EDS spectrum is as follows: Figure 6As shown, the main characteristic elements are niobium, iron and sulfur.

[0041] Example 4

[0042] A method for preparing FeNb2S4 comprises: first, uniformly mixing niobium trichloride (NbCl3) and FeS in a molar mass ratio of 1:3 under a nitrogen atmosphere to form granules, then placing the granules in a crucible; placing the crucible in a reactor; evacuating the reactor to a vacuum degree of 0.01 Pa; then heating the reactor to 900°C and maintaining the mixture for 30 minutes to terminate the reaction.

[0043] After cooling, the FeNb2S4 material can be directly selected from the reaction product. The FeNb2S4 material is tested by an energy dispersive spectrometer, and the obtained EDS spectrum is as follows: Figure 7 As shown, the main characteristic elements are niobium, iron and sulfur.

[0044] Example 5

[0045] A method for preparing FeNb2S4 comprises: first, uniformly mixing niobium trichloride (NbCl3) and ferrous disulfide (ferrous disulfide) in a molar mass ratio of 1:2 under a nitrogen atmosphere to form granules, then placing the granules into a crucible; placing the crucible into a reactor; evacuating the reactor to a vacuum degree of 0.01 Pa; and then heating the reactor to 700°C and maintaining the mixture for 30 minutes to terminate the reaction.

[0046] After cooling, the FeNb2S4 material can be directly selected from the reaction product. The FeNb2S4 material is tested by an energy dispersive spectrometer, and the obtained EDS spectrum is as follows: Figure 8 As shown, the main characteristic elements are niobium, iron and sulfur.

[0047] Example 6

[0048] A method for preparing FeNb2S4 comprises: first, uniformly mixing niobium trichloride (NbCl3) and FeS in a molar mass ratio of 1:4 under a nitrogen atmosphere to form granules, then placing the granules in a crucible; placing the crucible in a reactor; evacuating the reactor to a vacuum degree of 0.01 Pa; then heating the reactor to 800°C and maintaining the mixture for 60 minutes to terminate the reaction.

[0049] After cooling, the FeNb2S4 material can be directly selected from the reaction product. The FeNb2S4 material is tested by an energy dispersive spectrometer, and the obtained EDS spectrum is as follows: Figure 9 As shown, the main characteristic elements are niobium, iron and sulfur.

[0050] Comparative Example 1

[0051] 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.

[0052] Comparative Example 2

[0053] The difference from Example 1 is that the molar ratio of niobium trichloride NbCl3 to FeS is 1:5, and the other conditions are the same as in Example 1. Flake FeNb2S4 is found in the reaction product, and the reaction product contains a large amount of impurities.

[0054] Comparative Example 3

[0055] 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 in Example 4. A small amount of flaky FeNb2S4 is found in the reaction product, and the reaction product contains a large amount of impurities.

[0056] Comparative Example 4

[0057] A method for preparing FeNb2S4 includes uniformly mixing Nb2O5, ferrous sulfide, and coke at a mass ratio of 1:0.4:0.2 under an argon atmosphere, forming granules, and then placing the mixture into a crucible. The crucible is then placed into a reactor, and the atmosphere in the reactor is adjusted to argon. The temperature is then raised to 950°C and maintained for 30 minutes, completing the reaction. Testing indicates that no FeNb2S4 is formed in the reaction product.

[0058] The above is a further detailed description of the present invention in conjunction with specific preferred embodiments, and the specific implementation of the present invention should not be considered to be limited to these descriptions. For those skilled in the art to which the present invention belongs, several simple deductions or substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the scope of protection of the present invention.

Claims

1. A method for preparing FeNb2S4, characterized in that: The following steps are involved: Niobium trichloride and ferrous sulfide are uniformly mixed under a protective atmosphere to obtain a mixture, and then the mixture is placed in a reactor. The reactor is adjusted to a protective atmosphere or vacuum condition for high-temperature reaction to obtain FeNb2S4. The molar ratio of niobium trichloride to ferrous sulfide is 1:2-4.

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 temperature of the high-temperature reaction under the protective atmosphere is 700-950° C., and the reaction time is greater than 30 minutes.

4. The method for preparing FeNb2S4 according to claim 1, wherein The vacuum degree is less than or equal to 0.01Pa.

5. 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.

6. The method for preparing FeNb2S4 according to claim 5, characterized in that The preform is prepared by granulation or tableting.

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