A method for preparing zinc ferrite material

Abstract

The present invention discloses a preparation method of zinc ferrite materials, belonging to the technical field of new material preparation. The preparation method of the zinc ferrite materials is characterized by comprising the following steps: Step S1. Mix zinc salt, iron salt and sodium oleate and dissolve them in deionized water; Step S2. After stirring the mixed solution obtained in Step S1 evenly, adjust the pH value of the mixed solution; Step S3. Place the mixture obtained in Step S2 in a reaction kettle with a magnetic field and heat it to obtain zinc ferrite; Step S4. After separating the reddish-brown zinc ferrite obtained in Step S3 by a centrifuge, place it in a magnetic field and dry it at a certain temperature to obtain zinc ferrite with a mixed spinel structure. The present invention prepares zinc ferrite with a mixed spinel structure through a magnetic field, and utilizes the induction effect of the magnetic field on iron atoms to change the iron atoms from a single octahedral site to a mixed site of octahedral and tetrahedral sites. Therefore, the active sites in the electrocatalytic process are increased, and the catalytic reaction rate in the electrolysis of water process is increased.

Description

Technical Field

[0001] The present invention relates to a preparation method of zinc ferrite material, belonging to the technical field of new material preparation. Background Art

[0002] With the development of human social modernization, the increasingly prominent problems such as energy shortage, environmental pollution, greenhouse effect, and land desertification have made humans search for sustainable, clean, and inexpensive energy to replace fossil fuels that seriously pollute the environment and are non-renewable. Hydrogen energy is the most potential clean energy in the 21st century. The electrolysis water technology based on renewable energy is a potential high-efficiency and green hydrogen production approach. The hydrogen production reaction by electrolyzing water is slow and needs to be accelerated by adding a catalyst to make the hydrogen production rate faster. The most catalytically effective noble metal oxides are expensive and rare and cannot be widely used in industrial production. Researchers have conducted a large number of studies to find high-efficiency and inexpensive non-noble metal catalysts that can replace noble metals with high catalytic efficiency.

[0003] In recent years, zinc ferrite (ZnFe2O4) has attracted wide attention due to its excellent chemical and physical properties and special spinel structure. ZnFe2O4 is a typical iron-based transition metal composite metal oxide material with a spinel structure, belonging to the cubic crystal system, face-centered cubic structure, and its chemical general formula can be expressed as AB2O4, where A and B occupy two different positions, namely the tetrahedral position and the octahedral position, representing divalent metal cations and trivalent metal cations respectively. In ZnFe2O4, Zn 2+ occupies the A position of the tetrahedral interstitial, and Fe 3+ occupies the B position of the octahedral interstitial, belonging to the normal spinel structure. It has the characteristics of non-toxicity, easy preparation, and relatively low price, and has stable chemical and photochemical properties, high temperature resistance, chemical corrosion resistance, wear resistance, and generally does not react with acids and alkalis. However, ZnFe2O4 is a semiconductor material and has broad application prospects in the fields of magnetic storage, biology, photocatalysis, gas sensing, etc. The existing zinc ferrite as an electrolysis water hydrogen production catalyst has not been applied in the field of electrolysis water hydrogen production due to its poor conductivity and insufficient active sites. Therefore, we provide a preparation method of zinc ferrite material. Summary of the Invention

[0004] The present invention provides a preparation method of zinc ferrite material, aiming to prepare zinc ferrite with a mixed spinel structure, which has improved conductivity and increased active sites, so it can be used as an electrocatalyst in the field of electrolysis water hydrogen production to solve the problems raised in the above background art.

[0005] The present invention is realized as follows. A method for preparing zinc ferrite material includes the following steps:

[0006] Step S1. Mix zinc salt, iron salt and sodium oleate and dissolve them in deionized water;

[0007] Step S2. After stirring the mixed solution obtained in Step S1 evenly, adjust the pH value of the mixed solution;

[0008] Step S3. Place the mixture obtained in Step S2 in a reaction kettle with a magnetic field and heat it to obtain zinc ferrite;

[0009] Step S4. After separating the reddish-brown zinc ferrite obtained in Step S3 by a centrifuge, place it in a magnetic field and dry it at a certain temperature to obtain zinc ferrite with a mixed spinel structure;

[0010] Further, in Step S1, the zinc salt is zinc sulfate, zinc chloride or zinc nitrate.

[0011] Further, in Step S1, the iron salt is ferric sulfate, ferric chloride or ferric nitrate.

[0012] Further, in Step S1, the mixed molar ratio of the zinc salt and sodium oleate is 1:0.2 to 1:5.

[0013] Further, in Step S1, the mixed molar ratio of the zinc salt and the iron salt is 1:0.5 to 1:10.

[0014] Further, the pH value of the mixed solution in Step S2 is 9 to 14.

[0015] Further, in Step S3, the magnetic field intensity of the magnetic field reaction kettle is 0.05 to 5 Tesla.

[0016] Further, in Step S3, the magnetic field direction is perpendicular or parallel to the reaction kettle.

[0017] Further, in Step S3, the heating temperature is 90 to 150 o C, and the calcination time is 1 to 30 hours.

[0018] Further, in Step S4, the magnetic field intensity is 0.01 to 1 Tesla, the drying time is 1 to 10 hours, and the drying temperature is 20 to 90 o C.

[0019] In the method provided by the present invention, a preparation method of a zinc ferrite material prepares zinc ferrite with a mixed spinel structure by applying a magnetic field. The present invention utilizes the induction effect of the magnetic field on iron atoms to change the iron atoms from a single octahedral site to a mixed site of octahedral and tetrahedral sites. Therefore, the active sites in the electrocatalytic process are increased, and the catalytic reaction rate in the electrolysis of water process is increased. Compared with the prior art, by regulating the structure of the non-noble metal oxide catalyst through the magnetic field, the efficient catalytic reaction of its electrolysis of water can be realized. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 is a flowchart of a method for preparing a zinc ferrite material provided by the present invention;

[0021] Figure 2 is a surface morphology diagram of the zinc ferrite material prepared by the method for preparing a zinc ferrite material provided by the present invention;

[0022] Figure 3 is a catalytic performance test curve graph of zinc ferrite and commercial iridium oxide catalysts for the oxygen evolution reaction of water electrolysis; DETAILED DESCRIPTION OF THE EMBODIMENTS

[0023] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. Example 1

[0024] Step S1. A zinc salt, an iron salt and sodium oleate are mixed and dissolved in deionized water;

[0025] In this example, zinc nitrate, ferric chloride and sodium oleate are mixed in a certain proportion, where the molar ratio of zinc nitrate to ferric chloride is 1:2, and the molar ratio of zinc nitrate to sodium oleate is 1:0.5;

[0026] Step S2. After the mixed solution obtained in step S1 is stirred evenly, the pH value of the mixed solution is adjusted;

[0027] In this example, the pH value of the mixed solution obtained in step S1 is adjusted to 9;

[0028] Step S3. The mixture obtained in step S2 is placed in a reaction kettle with a magnetic field and heated to obtain zinc ferrite;

[0029] In this example, the mixture obtained in step S2 is placed in a reaction kettle perpendicular to a 0.5 tesla magnetic field and heated at 100 o °C and calcined for 10 hours.

[0030] Step S4. The reddish-brown zinc ferrite obtained in step S3 is separated by a centrifuge, placed in a magnetic field, and dried at a certain temperature to obtain zinc ferrite with a mixed spinel structure;

[0031] In this example, the reddish-brown zinc ferrite obtained in step S3 is separated by a centrifuge, placed in a 1 tesla magnetic field, and dried at 50 o °C for 6 hours.

[0032] By Figure 1The preparation process shown can produce zinc ferrite materials, and their surface morphology is as Figure 2 shown, which is a nano-spherical structure. Figure 3 This is the catalytic performance test of the prepared zinc ferrite material and commercial iridium oxide catalyst for the oxygen evolution reaction of water electrolysis. It can be seen from the figure that: in the OER test, the initial potential of the zinc ferrite catalyst becomes smaller than that of the commercial iridium oxide catalyst, and the current density of the catalyst is higher, indicating that the efficiency of water electrolysis is greatly improved by using this method. Example 2

[0033] Step S1. Mix zinc salt, iron salt and sodium oleate and dissolve them in deionized water;

[0034] In this example, zinc sulfate, ferric chloride and sodium oleate are mixed in a certain proportion, where the molar ratio of zinc sulfate to ferric chloride is 1:0.5, and the molar ratio of zinc sulfate to sodium oleate is 1:2;

[0035] Step S2. After stirring the mixed solution obtained in step S1 evenly, adjust the pH value of the mixed solution;

[0036] In this example, the pH value of the mixed solution obtained in step S1 is adjusted to 10;

[0037] Step S3. Place the mixture obtained in step S2 in a reaction kettle with a magnetic field and heat it to obtain zinc ferrite;

[0038] In this example, the mixture obtained in step S2 is placed in a reaction kettle perpendicular to a 0.05 Tesla magnetic field and heated at 90 o °C and calcined for 30 hours.

[0039] Step S4. After separating the reddish-brown zinc ferrite obtained in step S3 by a centrifuge, place it in a magnetic field and dry it at a certain temperature to obtain zinc ferrite with a mixed spinel structure;

[0040] In this example, after separating the reddish-brown zinc ferrite obtained in step S3 by a centrifuge, place it in a 0.01 Tesla magnetic field and dry it at 90 o °C for 1 hour. Example 3

[0041] Step S1. Mix zinc salt, iron salt and sodium oleate and dissolve them in deionized water;

[0042] In this example, zinc chloride, ferric nitrate and sodium oleate are mixed in a certain proportion, where the molar ratio of zinc chloride to ferric nitrate is 1:5, and the molar ratio of zinc chloride to sodium oleate is 1:0.2;

[0043] Step S2. Stir the mixed solution obtained in step S1 evenly and then adjust the pH value of the mixed solution;

[0044] In this embodiment, the pH value of the mixed solution obtained in step S1 is adjusted to 11;

[0045] Step S3. Place the mixture obtained in step S2 in a reaction kettle with a magnetic field and heat it to obtain zinc ferrite;

[0046] In this embodiment, the mixture obtained in step S2 is placed in a reaction kettle parallel to a 5 Tesla magnetic field and heated at 120 o C and calcined for 2 hours.

[0047] Step S4. After separating the reddish-brown zinc ferrite obtained in step S3 by a centrifuge, place it in a magnetic field and dry it at a certain temperature to obtain zinc ferrite with a mixed spinel structure;

[0048] In this embodiment, after separating the reddish-brown zinc ferrite obtained in step S3 by a centrifuge, place it in a 0.05 Tesla magnetic field and dry it at 20 o C for 10 hours. Example 4

[0049] Step S1. Mix zinc salt, iron salt and sodium oleate and dissolve them in deionized water;

[0050] In this embodiment, zinc chloride, ferric sulfate and sodium oleate are mixed in a certain proportion, where the molar ratio of zinc chloride to ferric sulfate is 1:8 and the molar ratio of zinc chloride to sodium oleate is 1:5;

[0051] Step S2. After stirring the mixed solution obtained in step S1 evenly, adjust the pH value of the mixed solution;

[0052] In this embodiment, the pH value of the mixed solution obtained in step S1 is adjusted to 14;

[0053] Step S3. Place the mixture obtained in step S2 in a reaction kettle with a magnetic field and heat it to obtain zinc ferrite;

[0054] In this embodiment, the mixture obtained in step S2 is placed in a reaction kettle parallel to a 4 Tesla magnetic field and heated at 150 o C and calcined for 1 hour.

[0055] Step S4. After separating the reddish-brown zinc ferrite obtained in step S3 by a centrifuge, place it in a magnetic field and dry it at a certain temperature to obtain zinc ferrite with a mixed spinel structure;

[0056] In this embodiment, after separating the reddish-brown zinc ferrite obtained in step S3 by a centrifuge, place it in a 0.25 Tesla magnetic field and dry it at 40 o C for 5 hours. Example 5

[0057] Step S1. Mix zinc salt, iron salt and sodium oleate and dissolve them in deionized water;

[0058] In this embodiment, zinc chloride, iron chloride and sodium oleate are mixed in a certain proportion. The molar ratio of zinc chloride to iron chloride is 1:10, and the molar ratio of zinc chloride to sodium oleate is 1:0.65;

[0059] Step S2. After stirring the mixed solution obtained in Step S1 evenly, adjust the pH value of the mixed solution;

[0060] In this embodiment, the pH value of the mixed solution obtained in Step S1 is adjusted to 13;

[0061] Step S3. Place the mixture obtained in Step S2 in a reaction kettle with a magnetic field and heat it to obtain zinc ferrite;

[0062] In this embodiment, the mixture obtained in Step S2 is placed in a reaction kettle perpendicular to a 2.5 Tesla magnetic field and heated at 180 o °C and calcined for 6 hours.

[0063] Step S4. After separating the reddish-brown zinc ferrite obtained in Step S3 by a centrifuge, place it in a magnetic field and dry it at a certain temperature to obtain zinc ferrite with a mixed spinel structure;

[0064] In this embodiment, after separating the reddish-brown zinc ferrite obtained in Step S3 by a centrifuge, place it in a 0.6 Tesla magnetic field and dry it at 80 o °C for 3 hours.

[0065] In summary, according to the induction effect of the magnetic field on magnetic iron atoms, the iron atoms in zinc ferrite are changed from a single octahedral site to a mixed site of octahedral and tetrahedral sites. Since the active sites in the electrocatalytic process are increased, the catalytic reaction rate in the electrolysis of water process is greatly improved, and the efficiency of electrolysis of water is enhanced. The zinc ferrite prepared by this method has excellent electrocatalytic performance. Compared with modern technologies, the present invention realizes the enhancement of the electrolysis of water catalytic performance by regulating the structure of non-precious metal oxide catalysts through a magnetic field, which provides a new idea for replacing precious metal electrolysis of water catalysts to realize industrial electrolysis of water hydrogen production technology in the future.

[0066] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing a zinc ferrite material, characterized in that, It includes the following steps: S1. Mix zinc salt, iron salt and sodium oleate and dissolve them in deionized water; S2. After stirring the mixed solution obtained in step S1 evenly, adjust the pH value of the mixed solution; S3. Place the mixture obtained in step S2 in a reaction kettle with a magnetic field and heat it to obtain zinc ferrite; S4. After separating the reddish-brown zinc ferrite obtained in step S3 by a centrifuge, place it in a magnetic field and dry it at a certain temperature to obtain zinc ferrite with a mixed spinel structure; In step S3, the magnetic field intensity of the magnetic field reaction kettle is 0.5 to 5 tesla; In step S3, the magnetic field direction of the magnetic field is perpendicular or parallel to the reaction kettle; In step S4, the magnetic field intensity is 0.01 to 1 tesla.

2. The preparation method of the zinc ferrite material according to claim 1, characterized in that In step S1, the zinc salt is zinc sulfate, zinc chloride or zinc nitrate.

3. The preparation method of the zinc ferrite material according to claim 1, characterized in that, In step S1, the iron salt is ferric sulfate, ferric chloride or ferric nitrate.

4. The preparation method of the zinc ferrite material according to claim 1, characterized in that, In step S1, the mixed molar ratio of the zinc salt and sodium oleate is 1:0.2 to 1:

5.

5. The preparation method of the zinc ferrite material according to claim 1, characterized in that, In step S1, the mixed molar ratio of the zinc salt and iron salt is 1:0.5 to 1:

10.

6. The preparation method of the zinc ferrite material according to claim 1, characterized in that, In step S2, the pH value of the mixed solution is 9 to 14.

7. The preparation method of the zinc ferrite material according to claim 1, characterized in that, In step S3, heating is carried out by calcination, and the heating temperature is 90 to 150 o °C, and the heating time is 1 to 30 hours.

8. The preparation method of the zinc ferrite material according to claim 1, characterized in that In step S4, the drying time is 1 to 10 hours, and the drying temperature is 20 to 90 o °C.

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