Cobalt intercalation niobium disulfide, preparation method and application

Abstract

The preparation method comprises the following steps: uniformly mixing cobalt, niobium and sulfur according to a ratio of 1: (2.8-3.1): (5.9-6.2) to obtain mixed powder, sealing and wrapping the mixed powder, and carrying out a synthetic reaction for 30-120 minutes under the conditions of 3-5.5 GPa and 1400-1600 DEG C to obtain the cobalt intercalation niobium disulfide. The preparation method is low in cost, simple in synthesis process, short in time and easy to control product quality.

Description

Technical Field

[0001] The invention relates to the technical field of antiferromagnetic materials, in particular to cobalt-intercalated niobium disulfide, a preparation method and application thereof. Background Art

[0002] Transition metal dichalcogenides (TMDs) have attracted widespread attention in recent years. This type of material has a wide range of applications in electronic devices, catalysts, energy storage, and sensors due to its unique electronic, optical, and mechanical properties. TMDs usually adopt a hexagonal 2H-XS2 structure, where X is a transition metal, and the crystal structure consists of layers that are bound to each other by weak van der Waals forces. In this type of material, magnetic atoms can be inserted between the layers. When the intercalation concentration reaches a critical 1 / 3, the material has a superlattice structure. Parkin, Marseglia, and Brown used neutron diffraction technology to study single crystal samples of CoNb3S6 and CoTa3S6 to determine the antiferromagnetic structure of the two compounds. Each magnetic unit cell in CoNb3S6 contains two Co atoms, and the magnetic moment of Co is 2.73μB, slightly lower than that of Co. 2+ The spin magnetic moment is 3μB. Ghimire et al. conducted magnetic and magnetotransport measurements on CoNb3S6 and found that it has a small linear magnetic susceptibility in planar and perpendicular magnetic fields (less than 0.1μB per chemical formula unit under a magnetic field of 6T). Among them, the magnetic susceptibility in the perpendicular direction is higher than that in the planar direction, but at temperatures below 29K, the magnetic susceptibility in the perpendicular direction shows obvious hysteresis. Magnetotransport measurements show that below the Néel temperature (TN=27.5K), there is a relatively large ferromagnetic Hall effect (AHE). These structural characteristics determine its wide potential application in electronic devices, spin electronics and energy storage devices.

[0003] Chemical vapor transport (CVT) is a common method for synthesizing TMDs and magnetic intercalated TMDs, which has good controllability and uniformity. However, the CVT method usually requires high reaction temperature and long reaction time, and it is difficult to accurately control the content and distribution of the intercalated metal. Summary of the invention

[0005] The present invention aims to provide a cobalt-intercalated niobium disulfide, a preparation method and an application thereof, which have low cost, simple synthesis process, short time and easy control of product quality.

[0006] In order to solve the above technical problems, the specific scheme adopted by the present invention is: a method for preparing cobalt-intercalated niobium disulfide, wherein cobalt, niobium and sulfur are uniformly mixed in a ratio of 1: (2.8-3.1): (5.9-6.2) to obtain a mixed powder, the mixed powder is sealed and packaged, and then a synthesis reaction is carried out at 3-5.5 GPa and 1400-1600° C. for 30-120 min to obtain cobalt-intercalated niobium disulfide.

[0007] Preferably, cobalt, niobium and sulfur are ground and mixed to obtain a mixed powder, and the grinding and mixing time is 1.5-2.5 hours.

[0008] Preferably, the particle sizes of cobalt, niobium and sulfur are all 5-200 μm.

[0009] Preferably, the mixed powder is placed in a mold, and then pre-pressed at 580-630 MPa to obtain a pre-pressed cylinder, the pre-pressed cylinder is placed in a high-pressure synthesis assembly, and finally the high-pressure synthesis assembly is placed in a synthesis chamber for high-temperature and high-pressure synthesis.

[0010] Preferably, a graphite tube is placed in a magnesium oxide liner, a hole is made transversely in the middle, an alumina ceramic tube and a thermocouple are inserted, and then the tube is placed in a pyrophyllite synthetic block, and the pre-pressed cylinder is placed in a BN sample chamber; one end of the BN sample chamber is closed with a BN sheet to form a BN column; the BN column is placed in a graphite tube, and graphite sheets are sequentially assembled at both ends of the graphite tube to form a graphite column; finally, dolomite rings, molybdenum sheets, steel sheets and steel caps are respectively assembled at both ends of the magnesium oxide liner to obtain a high-pressure synthetic assembly.

[0011] Preferably, the high-pressure synthesis assembly is placed in a synthesis chamber of a six-sided top press for high-temperature and high-pressure synthesis.

[0012] A cobalt-intercalated niobium disulfide is prepared by any one of the above methods for preparing the cobalt-intercalated niobium disulfide.

[0013] The above-mentioned application of cobalt-intercalated niobium disulfide as an antiferromagnetic material. Beneficial Effects

[0014] The present invention uses metallic cobalt, metallic niobium and elemental sulfur as initial raw materials, and directly synthesizes a two-dimensional layered antiferromagnetic material, cobalt intercalated niobium disulfide (CoNb3S6), under high temperature and high pressure conditions. Compared with the traditional chemical vapor deposition method, the reaction conditions of the present invention are mild and easy to control, the raw materials for preparation are easy to obtain and low in price, no impurities other than cobalt, niobium and sulfur are introduced, it is not easy to pollute the environment, and the synthesis efficiency is high. Therefore, the present invention provides a new way for the preparation of cobalt intercalated niobium disulfide and expands the research direction in the field of material synthesis. The obtained cobalt intercalated niobium disulfide exhibits excellent electromagnetic properties and has a wide range of potential applications in electronic devices, spin electronics and energy storage devices.

[0015] In addition, the high temperature and high pressure environment in the present invention allows for precise control of the amount and distribution of cobalt intercalation, thereby facilitating optimization of material properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the XRD pattern of CoNb3S6 prepared in Example 1 of the present invention.

[0017] Figure 2 This is the Raman spectrum of CoNb3S6 prepared in Example 1 of the present invention.

[0018] Figure 3 This is the SEM image of CoNb3S6 prepared in Example 1 of the present invention.

[0019] Figure 4 This is a graph showing the change in magnetic susceptibility of CoNb3S6 prepared in Example 1 of the present invention with temperature.

[0020] Figure 5 It is a schematic cross-sectional structure diagram of the high pressure synthesis assembly part in the present invention.

[0021] Markings in the figure: 1. Alumina ceramic tube, 2. Graphite tube, 3. Graphite sheet, 4. Dolomite ring, 5. Pyrophyllite synthetic block, 6. Thermocouple, 7. Magnesium oxide liner, 8. Molybdenum sheet, 9. Steel sheet, 10. Steel cap, 11. BN sample chamber, 12. Sample. DETAILED DESCRIPTION

[0023] The technical solution of the present invention is described below through two six embodiments:

[0024] Example 1

[0025] A method for preparing cobalt-intercalated niobium disulfide in this embodiment comprises the following steps:

[0026] 1) Selecting metal cobalt, metal niobium and elemental sulfur with a particle size of 5 to 200 μm as initial raw materials, and mixing them in a molar ratio of 1:3:6;

[0027] 2) Grinding the mixed cobalt, niobium and sulfur powders to obtain mixed powders, the grinding time is 2 hours;

[0028] 3) Place the mixed powder into a mold and pre-press it at a pressure of 600 MPa to obtain a pre-pressed cylinder;

[0029] 4) Place the pre-pressed cylinder into the high-pressure synthesis assembly, and finally place the high-pressure synthesis assembly into the synthesis chamber for high-temperature and high-pressure synthesis.

[0030] like Figure 5As shown, a graphite tube 2 is placed in a magnesium oxide liner 7, a hole is made transversely in the middle, an alumina ceramic tube 1 and a thermocouple 6 are inserted, and then the tube is placed in a pyrophyllite synthesis block 5, and the pre-pressed cylinder is placed in a BN sample bin 11 (tubular boron nitride) as a sample 12; one end of the BN sample bin is closed with a BN sheet to form a BN column; the BN column is placed in a graphite tube 2, and graphite sheets 3 are sequentially assembled at both ends of the graphite tube 2 to form a graphite column; finally, dolomite rings 4, molybdenum sheets 8, steel sheets 9 and steel caps 10 are respectively assembled at both ends of the magnesium oxide liner to obtain a high-pressure synthesis assembly. The high-pressure synthesis assembly is placed in the synthesis chamber of a six-sided top press, and kept at 1400°C and 3.0GPa for 60 minutes;

[0031] 5) After the synthesis is completed, the temperature is reduced and the pressure is released to obtain the two-dimensional layered antiferromagnetic material CoNb3S6.

[0032] The samples obtained in Example 1 were subjected to XRD (X-ray diffraction) test, Raman spectrum, SEM (scanning electron microscope) test and magnetic susceptibility test respectively.

[0033] from Figure 1 It can be seen from the XRD results that Example 1 prepared high-purity antiferromagnetic material CoNb3S6. The characteristic peak of CoNb3S6 in XRD is sharp and clear. Compared with the standard card, it is confirmed to be CoNb3S6, indicating that the preparation effect of this scheme is good and highly feasible. Figure 2 The inset in the figure shows the polarization mode of the antiferromagnetic material at room temperature. The Raman polarization mode includes A 1g 、E 1g and E 2g , see the detailed schematic diagram Figure 2 Figure 1. The characteristic peak position in the Raman spectrum is consistent with the standard spectrum, indicating that the synthesized sample does not have an impurity phase. Through XRD and Raman spectrum analysis, it is proved that the antiferromagnetic material CoNb3S6 prepared according to the technical solution of the present invention has high purity and the method is highly feasible. Figure 3 It shows that the antiferromagnetic material CoNb3S6 prepared in Example 1 has good density, a flat sample surface, and uniform element distribution, with the ratio of each element close to: Co:Nb:S≈1:3:6. Figure 4 It can be clearly seen that the material undergoes an antiferromagnetic transition at about 28 K. Compared with materials synthesized by other methods, the material prepared by the technical solution of the present invention is excellent in purity and crystallinity.

[0034] Example 2

[0035] The difference between this embodiment and embodiment 1 is that in step 4) of this embodiment, the temperature is 1450°C, the pressure is about 3.5 GPa, and the temperature and pressure are maintained for 60 minutes, and then the temperature is reduced and the pressure is released to take out the material to obtain a two-dimensional layered antiferromagnetic material CoNb3S6.

[0036] Example 3

[0037] The difference between this embodiment and embodiment 1 is that in step 4) of this embodiment, the temperature is 1500°C, the pressure is about 4 GPa, and the temperature and pressure are maintained for 60 minutes, and then the temperature is reduced and the pressure is released to take out the material to obtain a two-dimensional layered antiferromagnetic material CoNb3S6.

[0038] Example 4

[0039] The difference between this embodiment and embodiment 1 is that in step 4) of this embodiment, the temperature is 1550°C, the pressure is about 4.5 GPa, and the temperature and pressure are maintained for 60 minutes, and then the temperature is reduced and the pressure is released to take out the material to obtain a two-dimensional layered antiferromagnetic material CoNb3S6.

[0040] Example 5

[0041] The difference between this embodiment and embodiment 1 is that in step 4) of this embodiment, the temperature is 1600°C, the pressure is about 5 GPa, and the temperature and pressure are maintained for 60 minutes, and then the temperature is reduced and the pressure is released to take out the material to obtain a two-dimensional layered antiferromagnetic material CoNb3S6.

[0042] Example 6

[0043] The difference between this embodiment and embodiment 1 is that in step 4) of this embodiment, the temperature is 1600°C, the pressure is about 5.5 GPa, and the temperature and pressure are maintained for 60 minutes, and then the temperature is reduced and the pressure is released to take out the material to obtain a two-dimensional layered antiferromagnetic material CoNb3S6.

[0044] The upper and lower range values ​​of the process parameters (such as synthesis temperature, pressure, time, etc.) listed in the present invention can realize the present invention, and the embodiments are not listed one by one again. The above description is only a preferred embodiment of the present invention, which is used to illustrate the technical solution of the present invention and is not used to limit the present invention. Personnel in the relevant technical field can also make various changes, substitutions and modifications without departing from the spirit and scope of the present invention, so the equivalent technical solutions also belong to the scope of the present invention.

Claims

1. A method for preparing cobalt intercalated niobium disulfide, characterized in that: Cobalt, niobium and sulfur in a ratio of 1: (2.8-3.1): (5.9-6.2) are uniformly mixed to obtain a mixed powder. After the mixed powder is sealed and packaged, a synthesis reaction is carried out at 3-5.5 GPa and 1400-1600° C. for 30-120 minutes to obtain cobalt-intercalated niobium disulfide.

2. The method for preparing cobalt-intercalated niobium disulfide according to claim 1, characterized in that: Cobalt, niobium and sulfur are ground and mixed to obtain a mixed powder, and the grinding and mixing time is 1.5-2.5 hours.

3. The method for preparing cobalt-intercalated niobium disulfide according to claim 1, characterized in that: The particle size of cobalt, niobium and sulfur is 5-200 μm.

4. The method for preparing cobalt-intercalated niobium disulfide according to claim 1, characterized in that: The mixed powder is placed in a mold, and then pre-pressed at 580-630 MPa to obtain a pre-pressed cylinder, the pre-pressed pre-pressed cylinder is placed in a high-pressure synthesis assembly, and finally the high-pressure synthesis assembly is placed in a synthesis cavity for high-temperature and high-pressure synthesis.

5. The method for preparing cobalt-intercalated niobium disulfide according to claim 4, characterized in that: A graphite tube is placed in a magnesium oxide liner, a hole is drilled transversely in the middle, an alumina ceramic tube and a thermocouple are inserted, and then the tube is placed in a pyrophyllite synthetic block, and the pre-pressed cylinder is placed in a BN sample chamber; one end of the BN sample chamber is closed with a BN sheet to form a BN column; the BN column is placed in a graphite tube, and graphite sheets are sequentially assembled at both ends of the graphite tube to form a graphite column; finally, dolomite rings, molybdenum sheets, steel sheets and steel caps are respectively assembled at both ends of the magnesium oxide liner to obtain a high-pressure synthetic assembly.

6. The method for preparing cobalt-intercalated niobium disulfide according to claim 4, characterized in that: The high-pressure synthesis assembly is placed in the synthesis chamber of a six-sided top press for high-temperature and high-pressure synthesis.

7. A cobalt-intercalated niobium disulfide, characterized in that: The cobalt-intercalated niobium disulfide is prepared by any one of the preparation methods of claims 1-6.

8. Use of the cobalt-intercalated niobium disulfide as claimed in claim 7 as an antiferromagnetic material.

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