Preparation method for pure-phase 001 crystal orientation Ni3S2 nanocrystal based on reverse epitaxial growth method

Abstract

The invention relates to the technical field of nanocrystal materials, in particular to a preparation method for pure-phase 001 crystal orientation Ni3S2 nanocrystals based on a reverse epitaxial growth method, which comprises the following steps: S1.1, pretreating a metal substrate to fully remove impurities such as sweat stain, oil stain, oxide skin and residual acid liquor on the surface; s1.2, in the atmosphere, placing the mutagenesis seed crystal in a hydrothermal kettle, adding 45-50 mL of a liquid-phase transmitter, suspending the pretreated metal substrate under a liquid layer by using a polytetrafluoroethylene wire, sealing and storing, heating at 155-160 DEG C for 10-12 hours, cooling, taking out the metal substrate, and washing with ethanol and deionized water in turn for three times to obtain Ni3S2 nanocrystals; the substrate structure is selectively mutated by adopting a reverse epitaxial growth method and utilizing the reactivity of the film, so that the growth direction of the Ni3S2 crystal is effectively controlled, the pure-phase Ni3S2 crystal with a specific crystal face is obtained, meanwhile, the mutated seed crystal automatically falls off in the form of metal powder after participating in the reaction, the procedure of product separation is omitted, and the technological process is simplified.

Description

Technical Field

[0001] The present invention relates to the technical field of nanocrystalline materials, and in particular to a method for preparing a pure phase 001 crystal orientation Ni nanocrystalline material based on a reverse epitaxial growth method. 3 S 2 Method for preparing nanocrystals. Background Art

[0002] With the worsening of energy crisis and environmental pollution, the transformation of energy structure is unstoppable. The non-renewable and high carbon emissions of traditional fossil fuels have greatly restricted the development of human beings today. New high-quality energy sources such as batteries and hydrogen energy, as well as new energy storage technologies such as capacitors, have gradually entered the vision of the new era. All three have an urgent need for new materials with excellent electrical properties. At present, new energy technologies such as battery technology, electrocatalytic green hydrogen production technology, and supercapacitor technology are full of precious metal materials. Their excellent performance has attracted much attention, but their high cost and scarce reserves are daunting. The development of non-precious metal materials has gradually received widespread attention. Among them, Ni 3 S 2 The material is a semiconductor material with excellent conductivity due to its special Ni-Ni grid structure. It is widely favored in related fields and has achieved many innovative discoveries through defect engineering, crystal plane engineering, heterogeneous interface construction, doping technology and other means.

[0003] However, semiconductor devices often have strict requirements on the crystal orientation of material growth, and Ni 3 S 2 It is not the most thermodynamically stable sulfide. Traditional methods can only produce Ni with disordered crystal orientation. 3 S 2 Material, excellent pure phase Ni 3 S 2 The substrate is difficult to obtain directly. In view of this, a method based on reverse epitaxial growth is provided for pure phase 001 crystal orientation Ni 3 S 2 Method for preparing nanocrystals. Summary of the invention

[0004] The purpose of the present invention is to provide a method for producing a pure phase 001 crystal orientation Ni based on a reverse epitaxial growth method. 3 S 2 A method for preparing nanocrystals is provided to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides a pure phase 001 crystal orientation Ni based on a reverse epitaxial growth method. 3 S 2Preparation method of nanocrystals, S1.1, pre-treating the metal substrate to fully remove impurities such as sweat stains, oil stains, oxide scale, and residual acid;

[0006] S1.2, under the atmosphere, place the mutagenic seed crystal in a hydrothermal reactor, add 45-50mL of liquid phase mediator, and then suspend the pretreated metal substrate under the liquid layer with a polytetrafluoroethylene line. After sealing, heat it at 155-160℃ for 10-12h. After cooling, take out the metal substrate and wash it three times with ethanol and deionized water in turn to obtain Ni 3 S 2 Nanocrystals.

[0007] Ni 3 S 2 It has Ni metal clusters connected by metal bonds inside, which ensures its excellent electrical properties. Among the many crystal planes, only the (001) crystal plane can ensure that the Ni metal clusters on the surface are not destroyed, thus ensuring excellent surface properties.

[0008] Ni 3 S 2 During the preparation of nanocrystals, the deposition of the seed crystal on the metal substrate is guided first, that is, under hydrothermal conditions, the Bi 2 S 3 Dissolved in the solution, diffused upward along the concentration gradient with the internal liquid thermal circulation, and finally deposited on the surface of the suspended metal substrate, and then reverse epitaxially grown, depositing Bi on the surface 2 S 3 The film directly oxidizes the metal substrate, and after inducing the substrate to grow <001> Ni 3 S 2 After that, the participants 2 S 3 It will fall off by itself in the form of metal powder Bi, eliminating the power consumption of separating and purifying the product, and finally obtaining Ni with excellent electrical properties and pure phase. 3 S 2 Nanocrystals.

[0009] Preferably, in S1.1, the metal substrate is selected from a metal bulk material having sufficient reducing properties, including one of foamed nickel, foamed iron, nickel foil, and iron wire.

[0010] Preferably, in S1.1, the metal substrate pretreatment step is:

[0011] The metal substrate is cleaned in ultrasonic equipment with deionized water, acetone, 0.1-0.3M HCl solution and anhydrous ethanol in sequence, each cleaning time is 5-15 minutes, and finally dried in the shade.

[0012] Preferably, in S1.2, the atmosphere is one of air atmosphere and argon atmosphere.

[0013] Preferably, in S1.2, the mutation seed is selected from materials that can be deposited on a specific crystal surface, including Bi 2 S 3 Columnar crystal, Bi 2 O 3 A type of columnar crystal.

[0014] Preferably, in S1.2, the concentration of the mutagenic seed crystals is 0.5 mmol.

[0015] Preferably, in S1.2, the volume of the hydrothermal kettle is 100-150 mL.

[0016] Preferably, in S1.2, the liquid phase transmitter has a mass concentration of 0.05-0.15 g·ml -1 Na 2 S solution.

[0017] Preferably, in S1.2, Ni 3 S 2 Nanocrystals are pure phase Ni 3 S 2 Columnar nanocrystals, and the columnar crystals point to <001> .

[0018] Preferably, in S1.2, the induced crystal seeds fall off in the form of metal powder after participating in the reaction.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. This method is based on reverse epitaxial growth method for pure phase 001 crystal orientation Ni 3 S 2 In the preparation method of nanocrystals, in the ordinary epitaxial growth technology, the film growth is often induced on a specific substrate, and the crystal orientation of the substrate determines the crystal orientation of the film. The former is the cause and the latter is the effect. The present invention innovatively reverses the cause and effect, utilizes the reactivity of the film, selectively induces the substrate structure, and realizes the Ni 3 S 2 Effective control of crystal growth direction to obtain pure Ni with specific crystal faces 3 S 2 Crystal.

[0021] 2. After the traditional epitaxial technology completes the synthesis, the thin film wraps the substrate and is difficult to separate, so it cannot be used for the synthesis of pure phase materials. However, the reverse epitaxial technology developed by the present invention, after the internal substrate is completely transformed, the external film structure changes accordingly, loses adhesion and falls off by itself, and can be used for the synthesis of pure phase materials, and eliminates the process of product separation, simplifies the process flow, and realizes new applications of epitaxial technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Ni in Example 1 of the present invention 3 S 2 X-ray diffraction pattern.

[0023] Figure 2 is Ni in Example 1 of the present invention 3 S 2 Scanning electron microscope image of .

[0024] Figure 3 is Bi in Example 1 of the present invention 2 S 3 Transmission electron microscope image of .

[0025] Figure 4 is Bi in Example 1 of the present invention 2 S 3 Electron diffraction image of .

[0026] Figure 5 is Ni in Example 1 of the present invention 3 S 2 Transmission electron microscope image of .

[0027] Figure 6 is Ni in Example 1 of the present invention 3 S 2 Electron diffraction image of .

[0028] Figure 7 It is a comparison pattern of the X-ray diffraction pattern of Bi in Example 1 of the present invention.

[0029] Figure 8 Ni in Example 2 of the present invention 3 S 2 X-ray diffraction pattern.

[0030] Fig. 9 Ni in Example 2 of the present invention 3 S 2 Scanning electron microscope image of .

[0031] Fig.10 This is the X-ray diffraction pattern of the metal Bi powder in Example 2 of the present invention.

[0032] Fig.11 Ni in Example 2 of the present invention 3 S 2 Transmission electron microscope image of .

[0033] Fig.12 is Ni in Example 3 of the present invention 3 S 2 X-ray diffraction pattern.

[0034] Fig.13 is Ni in Example 3 of the present invention 3 S 2 Scanning electron microscope image of .

[0035] Fig.14 This is the X-ray diffraction pattern of the metal Bi powder in Example 3 of the present invention.

[0036] Fig.15 is Ni in Example 4 of the present invention 3 S 2 X-ray diffraction pattern.

[0037] Fig.16 is Ni in Example 4 of the present invention 3 S 2 Scanning electron microscope image of .

[0038] Fig.17 This is the X-ray diffraction pattern of the metal Bi powder in Example 4 of the present invention. DETAILED DESCRIPTION

[0039] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0040] A method for pure phase 001 crystal orientation Ni based on reverse epitaxial growth method of the present invention 3 S 2 Preparation method of nanocrystals:

[0041] S1.1. Pre-treat the metal substrate to fully remove the impurities such as sweat stains, oil stains, oxide scale, and residual acid on the surface;

[0042] S1.2, under the atmosphere, place the mutagenic seed crystal in a hydrothermal reactor, add 45-50mL of liquid phase mediator, and then suspend the pretreated metal substrate under the liquid layer with a polytetrafluoroethylene line. After sealing, heat it at 155-160℃ for 10-12h. After cooling, take out the metal substrate and wash it three times with ethanol and deionized water in turn to obtain Ni 3 S 2 Nanocrystals.

[0043] Among them, pure phase 001 crystal direction Ni 3 S 2 Nanocrystals are pure phase <001> Crystalline Ni 3 S 2 Nanocrystals.

[0044] Example 1: A method for pure phase 001 crystal orientation Ni based on reverse epitaxial growth method 3 S 2 The method for preparing nanocrystals comprises the following steps:

[0045] S1.1. Pre-treat the nickel foam by washing it in an ultrasonic device with deionized water, acetone, 0.1M HCl solution, and anhydrous ethanol in sequence, with each washing time being 10 minutes. Finally, dry it in the shade to fully remove impurities such as sweat stains, oil stains, oxide scale, and residual acid on the surface;

[0046] S1.2, in air atmosphere, 0.5 mmol of Bi 2 S 3 The columnar crystals were placed in a 100 mL hydrothermal reactor and 50 mL of 0.1 g mL -1 Na 2 S solution, and then the pretreated nickel foam was suspended under the liquid layer with a polytetrafluoroethylene line, sealed and heated at 160 ° C for 12 h, and the nickel foam was taken out after cooling, and washed with ethanol and deionized water three times in turn to obtain Ni 3 S 2 Nanocrystals.

[0047] Example 2: A method for pure phase 001 crystal orientation Ni based on reverse epitaxial growth method 3 S 2 The method for preparing nanocrystals comprises the following steps:

[0048] S1.1. Pre-treat the nickel wire by washing it in an ultrasonic device with deionized water, acetone, 0.1M HCl solution, and anhydrous ethanol in sequence, with each washing time being 10 minutes. Finally, dry it in the shade to fully remove impurities such as sweat stains, oil stains, oxide scale, and residual acid on the surface.

[0049] S1.2, in air atmosphere, 0.5 mmol of Bi 2 S 3 The columnar crystals were placed in a 150 mL hydrothermal kettle and 50 mL of 0.1 g mL -1 Na 2 S solution, and then the pretreated nickel wire was suspended under the liquid layer with a polytetrafluoroethylene wire, sealed and heated at 160 ° C for 12 h, and the nickel wire was taken out after cooling, and washed three times with ethanol and deionized water in turn to obtain Ni 3 S 2 Nanocrystals.

[0050] Example 3: A method for pure phase 001 crystal orientation Ni based on reverse epitaxial growth method 3 S 2The method for preparing nanocrystals comprises the following steps:

[0051] S1.1. Pre-treat the nickel foam by washing it in an ultrasonic device with deionized water, acetone, 0.1M HCl solution, and anhydrous ethanol in sequence, with each washing time being 10 minutes. Finally, dry it in the shade to fully remove impurities such as sweat stains, oil stains, oxide scale, and residual acid on the surface;

[0052] S1.2, in air atmosphere, 0.5 mmol of Bi 2 O 3 The columnar crystals were placed in a 100 mL hydrothermal reactor and 50 mL of 0.1 g mL -1 Na 2 S solution, and then the pretreated nickel foam was suspended under the liquid layer with a polytetrafluoroethylene line, sealed and heated at 160 ° C for 12 h, and the nickel foam was taken out after cooling, and washed with ethanol and deionized water three times in turn to obtain Ni 3 S 2 Nanocrystals.

[0053] Example 4: A method for pure phase 001 crystal orientation Ni based on reverse epitaxial growth method 3 S 2 The method for preparing nanocrystals comprises the following steps:

[0054] S1.1. Pre-treat the nickel foam by washing it in an ultrasonic device with deionized water, acetone, 0.1M HCl solution, and anhydrous ethanol in sequence, with each washing time being 10 minutes. Finally, dry it in the shade to fully remove impurities such as sweat stains, oil stains, oxide scale, and residual acid on the surface;

[0055] S1.2, under argon atmosphere, 0.5 mmol of Bi 2 O 3 The columnar crystals were placed in a 100 mL hydrothermal reactor and 50 mL of 0.1 g mL -1 Na 2 S solution, and then the pretreated nickel foam was suspended under the liquid layer with a polytetrafluoroethylene line, sealed and heated at 160 ° C for 12 h, and the nickel foam was taken out after cooling, and washed with ethanol and deionized water three times in turn to obtain Ni 3 S 2 Nanocrystals.

[0056] The present invention adopts the reverse epitaxial growth method to prepare Ni 3 S 2 Nanocrystals, in which Ni 3 S 2 The performance index inspection items and inspection standards of nanocrystals are as follows:

[0057] X-ray diffraction is a technique that determines the crystal structure of solid materials by measuring the diffraction patterns produced when X-rays pass through or are reflected by crystals. Scanning electron microscope images can be used to confirm the phase composition and purity of materials, determine the lattice parameters and crystal system of crystals, and detect whether there are impurity phases or polymorphism in samples. Scanning electron microscopes use a focused electron beam to scan the sample surface point by point, collect secondary electrons or backscattered electron signals, and generate high-resolution three-dimensional surface morphology images, which can be used to observe the surface morphology, particle size, distribution and morphology of samples. Transmission electron microscopes use high-energy electron beams to penetrate thin samples for imaging, which can provide internal structure information with nanometer or even atomic resolution, and can be used to observe the internal structure, grain boundaries and defects of nanomaterials and study the fine structure of crystals. Electron diffraction is a method of determining crystal structure by analyzing the diffraction patterns produced by the interaction between electron beams and crystals. It can quickly identify the symmetry and lattice parameters of crystals, confirm the crystal system and crystal orientation of crystals, identify different grain orientations in polycrystalline materials, and analyze the crystal structure and orientation distribution of nanomaterials.

[0058] Through the above test items, the Ni prepared in Examples 1-4 and Comparative Examples 1-3 3 S 2 The nanocrystals were tested and the data obtained are shown in the attached figure of the specification.

[0059] Since the present invention adopts the reverse epitaxial growth method to prepare Ni 3 S 2 Nanocrystals effectively increase the Ni 3 S 2 The role of nanocrystals in terms of pure phase, specific crystal planes and ease of separation is as follows:

[0060] Figure 1 Ni in the product 3 S 2 X-ray diffraction pattern confirms that it is pure phase Ni 3 S 2 .

[0061] Figure 2 Ni 3 S 2 Scanning electron microscope image of the nanocrystals, showing columnar nanocrystals.

[0062] Figure 3 Bi is the reactant 2 S 3 Transmission electron microscope image of the nanocrystals, showing columnar nanocrystals.

[0063] Figure 4 Bi is the reactant 2 S 3 The electron diffraction image of Figure 3After fast Fourier transform, we get Figure 3 By contrast, it is visible Figure 3 The columnar crystals point to <001> .

[0064] Figure 5 Ni 3 S 2 Transmission electron microscope image of the nanocrystals, showing columnar nanocrystals.

[0065] Figure 6 Ni 3 S 2 The electron diffraction image of Figure 5 After fast Fourier transform, we get Figure 5 By contrast, it is visible Figure 5 The columnar crystals point to <001> . Guarantee and Figure 3 The specific crystal orientation is suppressed, confirming epitaxial growth.

[0066] Figure 7 The X-ray diffraction pattern comparison pattern of the product Bi confirms that it is indeed Bi alone.

[0067] Figure 8 Ni in the product 3 S 2 X-ray diffraction pattern confirms that it is pure phase Ni 3 S 2 .

[0068] Fig. 9 Ni in the product 3 S 2 The scanning electron microscope image shows a columnar crystal structure similar to that of Example 1.

[0069] Fig.10 The X-ray diffraction pattern of the metallic Bi powder in the product confirms that it is pure phase Bi.

[0070] Fig.11 Ni in the product 3 S 2 The transmission electron microscope image shows a columnar crystal structure similar to that of Example 1.

[0071] Fig.12 Ni in the product 3 S 2 X-ray diffraction pattern confirms that it is pure phase Ni 3 S 2 .

[0072] Fig.13 Ni in the product 3 S 2 The scanning electron microscope image shows a columnar crystal structure similar to that of Example 1.

[0073] Fig.14 The X-ray diffraction pattern of the metallic Bi powder in the product confirms that it is pure phase Bi.

[0074] Fig.15 Ni in the product 3 S 2 X-ray diffraction pattern confirms that it is pure phase Ni 3 S 2 .

[0075] Fig.16 Ni in the product 3 S 2 The scanning electron microscope image shows a columnar crystal structure similar to that of Example 1.

[0076] Fig.17 The X-ray diffraction pattern of the metallic Bi powder in the product confirms that it is pure phase Bi.

[0077] In summary, the reverse epitaxial growth method is used to guide the deposition of the seed on the metal substrate, and then the Bi 2 S 3 As the internal liquid heat circulation diffuses upward along the concentration gradient, it is deposited on the surface of the suspended metal substrate, and then grows in reverse epitaxially, inducing the substrate to grow <001> crystal orientation, obtaining pure phase Ni with excellent electrical properties 3 S 2 Nanocrystals, Bi 2 S 3 It falls off in the form of metal powder Bi, eliminating the power consumption of separating and purifying the product, and overcoming the problem of the traditional process generating the impure phase Ni with chaotic crystal orientation. 3 S 2 problem.

[0078] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above embodiments, and the above embodiments and descriptions are only preferred examples of the present invention, and are not intended to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, and these changes and improvements all fall within the scope of the present invention to be protected.

Claims

1. A method for preparing pure phase 001 crystal orientation Ni3S2 nanocrystals based on reverse epitaxial growth method, characterized in that: S1.

1. Pre-treat the metal substrate to fully remove the impurities such as sweat stains, oil stains, oxide scale, and residual acid on the surface; S1.

2. Place the induced crystal seeds in a hydrothermal autoclave under the atmosphere, add 45-50 mL of liquid phase mediator, and then suspend the pretreated metal substrate under the liquid layer with a polytetrafluoroethylene line. After sealing, heat it at 155-160°C for 10-12h. After cooling, take out the metal substrate and wash it three times with ethanol and deionized water in turn to obtain Ni3S2 nanocrystals.

2. The method for preparing pure phase 001 crystal orientation Ni3S2 nanocrystals based on reverse epitaxial growth method according to claim 1, characterized in that: In the above S1.1, the metal substrate is selected from a metal bulk material having sufficient reducing properties, including foamed nickel, foamed iron, nickel foil, and iron wire.

3. The method for preparing pure phase 001 crystal orientation Ni3S2 nanocrystals based on reverse epitaxial growth method according to claim 1, characterized in that: In S1.1, the metal substrate pretreatment steps are: The metal substrate is cleaned in ultrasonic equipment with deionized water, acetone, 0.1-0.3M HCl solution and anhydrous ethanol in sequence, each cleaning time is 5-15 minutes, and finally dried in the shade.

4. The method for preparing pure phase 001 crystal orientation Ni3S2 nanocrystals based on reverse epitaxial growth method according to claim 1, characterized in that: In the above S1.2, the atmosphere is one of air atmosphere and argon atmosphere.

5. The method for preparing pure phase 001 crystal orientation Ni3S2 nanocrystals based on reverse epitaxial growth method according to claim 1, characterized in that: In S1.2, the mutation seed is selected from a material that can be deposited on a specific crystal plane, including one of Bi2S3 columnar crystals and Bi2O3 columnar crystals.

6. The method for preparing pure phase 001 crystal orientation Ni3S2 nanocrystals based on reverse epitaxial growth method according to claim 1, characterized in that: In the S1.2, the concentration of the mutagenic seed crystals is 0.5 mmol.

7. The method for preparing pure phase 001 crystal orientation Ni3S2 nanocrystals based on reverse epitaxial growth method according to claim 1, characterized in that: In S1.2, the volume of the hydrothermal kettle is 100-150 mL.

8. The method for preparing pure phase 001 crystal orientation Ni3S2 nanocrystals based on reverse epitaxial growth method according to claim 1, characterized in that: In S1.2, the liquid phase transmitter has a mass concentration of 0.05-0.15 g·mL -1 of Na2S solution.

9. The method for preparing pure phase 001 crystal orientation Ni3S2 nanocrystals based on reverse epitaxial growth method according to claim 1, characterized in that: In S1.2, the Ni3S2 nanocrystals are pure phase Ni3S2 columnar nanocrystals.

10. The method for preparing pure phase 001 crystal orientation Ni3S2 nanocrystals based on reverse epitaxial growth method according to claim 1, characterized in that: In S1.2, the mutagenic seed crystals fall off in the form of metal powder after participating in the reaction.

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