阅读说明：本技术 一种金属硫化物多孔单晶的制备方法 (Preparation method of metal sulfide porous single crystal ) 是由 刘岗 张露露 杨勇强 成会明 于 2021-09-10 设计创作，主要内容包括：本发明涉及纳米材料制备领域,具体为一种金属硫化物多孔单晶的制备方法。首先使用浸渍-硫化的方法在预制模板上植入对应目标硫化物的晶种,然后利用包括但不限于水热法在模板中生长硫化物,最后去除模板得到具有预制模板反结构的金属硫化物多孔单晶颗粒。本发明基于电化学反应中催化剂对活性位点与电子传输的特殊要求,利用廉价、易得的原料,通过简单易操作的方法得到可暴露内外表面且利于电子传输的具有三维多孔单晶结构的金属硫化物。该方法使得制备金属硫化物多孔单晶成为可能,操作简便,工艺简单,具备大规模应用的潜力。(The invention relates to the field of nano material preparation, in particular to a preparation method of a metal sulfide porous single crystal. Firstly, a seed crystal corresponding to a target sulfide is implanted on a prefabricated template by using a dipping-vulcanizing method, then the sulfide grows in the template by using a hydrothermal method including but not limited to, and finally the template is removed to obtain the metal sulfide porous single crystal particles with the reverse structure of the prefabricated template. Based on the special requirements of a catalyst on active sites and electron transmission in electrochemical reaction, the invention obtains the metal sulfide which can expose the inner and outer surfaces and is beneficial to electron transmission and has a three-dimensional porous single crystal structure by using cheap and easily-obtained raw materials and a simple and easily-operated method. The method makes the preparation of the metal sulfide porous single crystal possible, is simple and convenient to operate, has a simple process, and has the potential of large-scale application.)

1. A preparation method of a metal sulfide porous single crystal is characterized in that a seed crystal corresponding to a target sulfide is implanted on a prefabricated template by using a dipping-vulcanizing method, then a sulfide grows in the template by using a hydrothermal method, a solvothermal method, a liquid phase reaction method, a CVD method or a molten salt method, and finally the template is removed to obtain metal sulfide porous single crystal particles with the reverse structure of the prefabricated template.

2. The method for preparing a porous single crystal of a metal sulfide as claimed in claim 1, wherein the pre-fabricated template is implanted with a seed crystal corresponding to the target sulfide by dipping-sulfidizing method, i.e. the pre-fabricated template is placed in a dipping solution to be fully adsorbed, and then the pre-fabricated template is washed to remove the excessive adsorbate and dried, and the adsorbate in the template is sulfidized to obtain the template with the pre-fabricated sulfide seed crystal.

3. The method for preparing a metal sulfide porous single crystal as claimed in claim 2, wherein the dipping solution is an inorganic salt solution containing a corresponding metal element or an organic chelate solution containing a corresponding metal element, and the solvent is an inorganic solvent or an organic solvent.

4. The method for producing a porous single crystal of a metal sulfide as claimed in claim 3, wherein the inorganic salt solution is NiCl₂、FeCl₃、CoCl₂Or CuCl₂The organic chelate solution is ferrocene or nickelocene solution, and the solvent is water, benzene or ether.

5. The method for preparing a porous single crystal of a metal sulfide as set forth in claim 2, wherein the sulfur source used in the sulfidation comprises an organic or inorganic sulfur-containing substance, the sulfidation is carried out by a method comprising hydrothermal, solvothermal or atmospheric tube furnace heat treatment, and the sulfidation is carried out by placing the prefabricated template adsorbing the seed crystal precursor in a solution or atmosphere containing the sulfur source at a controlled temperature.

6. The method of producing a metal sulfide porous single crystal according to claim 5, wherein the sulfur source is sulfur powder, hydrogen sulfide, thiocyanic acid, or thiourea.

7. The method for preparing a metal sulfide porous single crystal as claimed in claim 1, wherein the prefabricated template comprises an SBA-15 template, an MCM-41 template, an HMM template, an Anodic Alumina (AAO) template, an SiO₂A nanosphere close-packed template or a polystyrene sphere close-packed template; in SiO₂In the nanosphere close-packed template or polystyrene sphere close-packed template, the average particle size of close-packed spheres is 20-80 nm.

8. The method for producing a porous single crystal of a metal sulfide as claimed in claim 1, wherein the sulfide is grown in the template by a hydrothermal method, a solvothermal method, a liquid phase reaction method, a CVD method or a molten salt method; wherein:

the outer sleeve of the reaction kettle used in the hydrothermal method or solvothermal method growth system is made of one of stainless steel, aluminum alloy, copper and tantalum, the inner container of the reaction kettle is made of one of polytetrafluoroethylene and high-density polyethylene, a prefabricated template with sulfide seed crystals in advance is placed in the inner container containing precursor solution during reaction, and the reaction kettle is sealed and then placed under hydrothermal or solvothermal conditions for reaction;

the liquid phase reaction method is that a prefabricated template with preset sulfide seed crystals is put into a normal pressure container containing reaction liquid for reaction;

the CVD method is that a tubular furnace is used as a reaction environment, the temperature and the reaction atmosphere are controlled, and a precursor containing metal elements and a sulfur source are promoted to enter a prefabricated template with preset sulfide seed crystals for reaction;

the molten salt method is to mix a precursor containing metal elements, a sulfur source and a prefabricated template preset with sulfide seed crystals, and to melt the metal precursor and the sulfur source to promote the reaction.

9. The method for preparing a metal sulfide porous single crystal according to claim 1, wherein the method of removing the template comprises chemical dissolution or high-temperature ablation; removing the inorganic template by using alkaline, acidic or ammonium bifluoride solution; for organic templates, ablation removal is performed using a thermal treatment.

10. The method for preparing a metal sulfide porous single crystal according to claim 1, wherein the technical parameters of the metal sulfide porous single crystal particle are: the particle size is 200 nm-6 μm, and the average pore diameter is 20-80 nm.

Technical Field

The invention relates to the field of nano material preparation, in particular to a preparation method of a metal sulfide porous single crystal.

Background

Metal sulfides have higher ionic and electronic conductivity than metal oxides and are widely used in electrochemical energy storage and electrocatalysis. The shape and surface structure of the metal sulfide directly influence the contact of the metal sulfide and the electrolyte, and have key influence on the performance. The introduction of the pore structure is a powerful means for improving the electrochemical performance of the metal sulfide: the specific surface area of the porous sample is large, the inner side surface and the outer side surface can participate in electrochemical reaction, and the utilization rate of the sample is high; after the pore structure is introduced, the inner surface and the outer surface can be contacted with the electrolyte, so that the number of reaction sites can be increased, and the remarkable performance improvement is brought; the introduction of the pore structure can also effectively relieve the volume expansion effect, and the stability and the safety of the battery are greatly improved. Meanwhile, compared with polycrystalline particles, the single crystal particles avoid the scattering of electron conduction by crystal boundaries, and are more favorable for the transmission of electrons. In conclusion, the preparation of the metal sulfide with the porous single crystal structure has very important scientific and application values.

In recent years, a method for synthesizing a metal oxide porous single crystal having a prefabricated template reverse structure using a preset seed attracts researchers' attention due to its simple and universal process. In this method, SiO is generally used₂And (3) taking the nanosphere close-packed structure as a template, pre-seeding by using a metal salt hydrolysis method, adding the template after pre-seeding into a hydrothermal synthesis process, and after the hydrothermal process is finished, etching by using a hot alkali solution to remove the template to obtain the metal oxide porous single crystal with the template reverse structure. Document 1[ Nature 2013,495,215]Document 2[ chem]And document 3[ chem. mater.2014,26,5700]The method is adopted and developed to obtain TiO₂、SnO₂、ZrO₂Porous of a series of metal oxidesAnd (3) single crystal. In terms of sulfide, although document 4[ J.Am.chem.Soc.2017,139,13604-13607]And document 5[ J.Am.chem.Soc.2014,136, 8895-8898]Reports of mesoporous FeS₂、CoS₂And NiS₂And document 6 ACS Nano 2020,14,4, 4141-]Reported porous MoS₂/CoMo₂S₄But none are single crystal materials.

Until now, no documents and published patents have been found for a method for preparing a porous single crystal of a metal sulfide using a prefabricated template.

Disclosure of Invention

The invention aims to provide a simple and universal preparation method of a metal sulfide porous single crystal, which can effectively synthesize a metal sulfide with a three-dimensional porous single crystal structure.

The technical scheme of the invention is as follows:

a process for preparing the porous monocrystal of metallic sulfide includes such steps as immersing in the seed crystal of sulfide, growing sulfide in template by hydrothermal method, solvothermal method, liquid-phase reaction method, CVD method or fused salt method, and removing template to obtain the porous monocrystal particles of metallic sulfide with reverse structure.

The preparation method of the metal sulfide porous single crystal comprises the steps of implanting seed crystals corresponding to target sulfides into a prefabricated template by using a dipping-vulcanizing method, namely putting the prefabricated template into dipping solution for full adsorption, then washing to remove redundant adsorbates, drying, vulcanizing the adsorbates in the template, and obtaining the template with the preset sulfide seed crystals.

According to the preparation method of the metal sulfide porous single crystal, the dipping solution is an inorganic salt solution containing corresponding metal elements or an organic chelate solution containing corresponding metal elements, and the solvent is an inorganic solvent or an organic solvent.

The preparation method of the metal sulfide porous single crystal comprises the step of preparing the inorganic salt solution of NiCl₂、FeCl₃、CoCl₂Or CuCl₂The organic chelate solution is ferrocene or nickelocene solution, and the solvent is water and benzeneOr diethyl ether.

According to the preparation method of the metal sulfide porous single crystal, a sulfur source adopted in vulcanization comprises an organic or inorganic sulfur-containing substance, the vulcanization is carried out by adopting a mode of hydrothermal treatment, solvothermal treatment or heat treatment in an atmosphere tube furnace, a prefabricated template adsorbing a seed crystal precursor is placed in a solution or atmosphere containing the sulfur source, and the vulcanization is realized at a controlled temperature.

In the preparation method of the metal sulfide porous single crystal, the sulfur source is sulfur powder, hydrogen sulfide, thiocyanic acid or thiourea.

The preparation method of the metal sulfide porous single crystal comprises the steps of preparing templates including an SBA-15 template, an MCM-41 template, an HMM template, an Anodic Aluminum Oxide (AAO) template and SiO₂A nanosphere close-packed template or a polystyrene sphere close-packed template; in SiO₂In the nanosphere close-packed template or polystyrene sphere close-packed template, the average particle size of close-packed spheres is 20-80 nm.

According to the preparation method of the metal sulfide porous single crystal, a hydrothermal method, a solvothermal method, a liquid phase reaction method, a CVD (chemical vapor deposition) method or a molten salt method is used for growing sulfides in a template; wherein:

the outer sleeve of the reaction kettle used in the hydrothermal method or solvothermal method growth system is made of one of stainless steel, aluminum alloy, copper and tantalum, the inner container of the reaction kettle is made of one of polytetrafluoroethylene and high-density polyethylene, a prefabricated template with sulfide seed crystals in advance is placed in the inner container containing precursor solution during reaction, and the reaction kettle is sealed and then placed under hydrothermal or solvothermal conditions for reaction;

the liquid phase reaction method is that a prefabricated template with preset sulfide seed crystals is put into a normal pressure container containing reaction liquid for reaction;

the CVD method is that a tubular furnace is used as a reaction environment, the temperature and the reaction atmosphere are controlled, and a precursor containing metal elements and a sulfur source are promoted to enter a prefabricated template with preset sulfide seed crystals for reaction;

the molten salt method is to mix a precursor containing metal elements, a sulfur source and a prefabricated template preset with sulfide seed crystals, and to melt the metal precursor and the sulfur source to promote the reaction.

The method for removing the template comprises the steps of chemical dissolution or high-temperature ablation; removing the inorganic template by using alkaline, acidic or ammonium bifluoride solution; for organic templates, ablation removal is performed using a thermal treatment.

The preparation method of the metal sulfide porous single crystal comprises the following technical parameters of metal sulfide porous single crystal particles: the particle size is 200 nm-6 μm, and the average pore diameter is 20-80 nm.

The design idea of the invention is as follows:

the invention puts the prefabricated template into dipping solution for full adsorption, then washes to remove redundant adsorbate and dries, carries on the first vulcanization to the adsorbate in the template, obtains the template with preset sulfide seed crystal, the first vulcanization has the following functions: obtaining sulfide seed crystal as nucleation center for the growth of the subsequent metal sulfide.

The invention uses a hydrothermal method including but not limited to grow sulfide in the template, and carries out the second vulcanization, and the second vulcanization has the functions of: and growing the metal sulfide.

Based on the special requirements of an electrochemical reaction catalyst on active sites and electron transmission, the metal sulfide which can expose the inner and outer surfaces and is beneficial to electron transmission and has a three-dimensional porous single crystal structure is obtained by using cheap and easily-obtained raw materials and a simple and easily-operated method.

The invention has the advantages and beneficial effects that:

1. the dipping-vulcanizing method adopted by the invention is simpler, and can realize the seed crystal implantation of various metal sulfides, thereby realizing the preparation of various metal sulfide porous single crystals.

2. The template used in the method is not limited to a specific template, so that the pore size distribution and the spatial distribution of pores can be regulated and controlled by changing the template to obtain the porous monocrystalline metal sulfide particles with the corresponding template reverse structures.

3. The method of the invention makes the preparation of the metal sulfide porous single crystal possible, has simple and convenient operation and simple process, and has the potential of large-scale application.

Drawings

FIG. 1: porous single crystal NiS₂(MSC-NiS₂) With non-porous single crystal NiS₂(Solid-NiS₂) XRD pattern of (a). In the figure, the abscissa 2Theta represents the diffraction angle 2 θ (°), and the ordinate Intensity represents the relative Intensity (a.u ℃).

FIG. 2: porous single crystal NiS₂(MSC-NiS₂) With non-porous single crystal NiS₂(Solid-NiS₂) Comparing the shapes of the two parts. (a) Pattern (b) is porous single crystal NiS₂(MSC-NiS₂) Morphology under different magnification; (c) - (d) is non-porous monocrystalline NiS₂(Solid-NiS₂) Morphology at different magnifications.

FIG. 3: porous single crystal NiS₂(MSC-NiS₂) With non-porous single crystal NiS₂(Solid-NiS₂) And (5) comparing the appearance under a transmission electron microscope. (a) - (b) is porous monocrystalline NiS₂The general morphology image and the high resolution image of (c) - (d) are non-porous single crystal NiS₂General morphology and high resolution phase; (a) the insets in (c) are selected diffraction spot patterns of the corresponding particles.

FIG. 4: porous single crystal NiS₂(MSC-NiS₂) With non-porous NiS₂(Solid-NiS₂) Nitrogen adsorption curve versus pore size distribution for the sample (inset). In the nitrogen adsorption curve, the abscissa P/P₀Represents relative pressure, and the ordinate Quantity Adsorbed represents the amount of adsorption (cm)³(iv)/g); in the Pore size distribution (inset), the abscissa Pore Dimeter represents Pore size (nm) and the ordinate dV/dD represents Pore volume (cm)³/g)。

FIG. 5: porous single crystal NiS₂(MSC-NiS₂) With non-porous NiS₂(Solid-NiS₂) Comparing the electrocatalytic oxygen production performance of the samples. The abscissa Bias represents the applied voltage (V vs RHE) and the ordinate Current Density represents the Current Density (mA cm)^-2)。

Detailed Description

With porous single crystal NiS₂The preparation of (2) is described as an example, specifically describing the embodiment of the scheme: take 2g of SiO₂The nanosphere close-packed template is added with NiCl with the concentration of 0.01mmol/L₂·6H₂In an aqueous O solution, stirring at room temperature 12 h; and (3) after standing for 3 minutes, pouring out liquid, washing the template for 3-5 times by using deionized water, drying the template at 60 ℃, and fully adsorbing Ni substances on the template. And (3) putting the dried template into a 600 ℃ tubular furnace, heating for 60min, taking nitrogen or argon as a carrier gas, wherein the carrier gas flow is 50sccm, placing 1g of thiourea on the upstream of the carrier gas flow, driving the gas generated by heating and decomposing the thiourea to pass through the template by the carrier gas, and vulcanizing the Ni substance adsorbed on the template to change the template into a uniform gray preset seed crystal template, which indicates that the preset seed crystal is finished.

Wherein, SiO₂The meaning and technical parameters of the nanosphere close-packed template are: the template is made of nano-scale spherical SiO₂Is densely packed with SiO₂The particle size of the nanospheres is about 50 nm.

The reaction kettle is formed by combining a stainless steel outer sleeve and a polytetrafluoroethylene inner container, and the polytetrafluoroethylene inner container forms an inner cavity of the reaction kettle. Adding 10ml of deionized water into a polytetrafluoroethylene liner of a reaction kettle, and adding 2g of thiourea and 0.054g of NiCl₂·6H₂O as precursor, 0.061g of FeCl₃·6H₂And O is used as a morphology control agent, fully stirred until the O is completely dissolved, and then 0.4g of a preset seed crystal template is added. And sealing the polytetrafluoroethylene lining into a stainless steel outer sleeve, heating the polytetrafluoroethylene lining to 180 ℃ in an oven, and preserving the heat for 2.5 hours. After cooling to room temperature, washing and drying the large template particles in the polytetrafluoroethylene lining, and then adding 100ml of NH with the molar concentration of 2M₄HF₂Stirring in water solution at normal temperature for 12h, etching the template, passing through 6NH₄HF₂+2SiO₂＝＝＝(NH₄)₂SiF₆+(NH₄)₄SiO₄+6HF reaction to remove SiO₂Silicon spheres. After the etching is finished, cleaning the product by using a pouring and washing method until the cleaning solution is neutral, drying and collecting the sample to obtain the NiS with the three-dimensional porous single crystal structure₂Particles with a particle size of hundreds of nanometers to several micrometers (200nm to 6 microns) and an average pore diameter of 30.5 nm.

The present invention will be explained in further detail below by way of examples and figures.

Example 1

Porous single crystal NiS prepared by silicon oxide nanosphere (50nm) close-packed template with seed crystals preset by adding impregnation method₂(MSC-NiS₂) And non-porous single crystal NiS prepared without adding prefabricated template₂(Solid-NiS₂) For comparison, the phase of a sample prepared according to this method was investigated.

X-ray test equipment and conditions: rigaku D/max 2500, Cu Ka ray. As shown in FIG. 1, is porous single crystal NiS₂With non-porous single crystal NiS₂X-ray diffraction pattern of (a). As can be seen from the figure, the added template has no influence on the phase of the sample, still has the structure of the wulfenite and is a single phase; meanwhile, the diffraction peak of the porous single crystal sample is significantly broadened compared to that of the non-porous single crystal sample, which can be understood as the scattering effect of the porous structure on X-rays.

Example 2

Porous single crystal NiS prepared by silicon oxide nanosphere (50nm) close-packed template with seed crystals preset by adding impregnation method₂(MSC-NiS₂) And non-porous single crystal NiS prepared without adding prefabricated template₂(Solid-NiS₂) As a comparison, the relationship of the prefabricated template to the pore structure of the particles was studied.

The appearance characterization equipment comprises: scanning electron microscope, FEI Nova 620. As shown in FIG. 2, it is apparent that MSC-NiS₂A large amount of pore structure exists on the particles, while Solid-NiS₂The particles have no holes, thus proving the effectiveness of the preparation method of the sulfide porous single crystal.

Example 3

Porous single crystal NiS prepared by silicon oxide nanosphere (50nm) close-packed template with seed crystals preset by adding impregnation method₂(MSC-NiS₂) And non-porous single crystal NiS prepared without adding prefabricated template₂(Solid-NiS₂) For comparison, the single crystal characteristics of the three-dimensional porous single crystal particles under the action of the template were investigated.

The appearance characterization equipment comprises: JEOL 2010, operating voltage 200 kV. As shown in fig. 3, the diffraction pattern is taken for high resolution and extraction of porous single crystal particles prepared under the template conditions. The clear high-resolution spectrum and the single diffraction spot type indicate that the particles are single crystals, and the effectiveness of the preparation method of the metal sulfide porous single crystals is proved.

Example 4

Porous single crystal NiS prepared by silicon oxide nanosphere (50nm) close-packed template with seed crystals preset by adding impregnation method₂(MSC-NiS₂) And non-porous single crystal NiS prepared without adding prefabricated template₂(Solid-NiS₂) For comparison, the specific surface area and pore size distribution of the metal sulfide porous single crystal particles were investigated.

Specific surface area and pore size distribution test conditions: micromedia 2020, using nitrogen as the adsorption medium, obtains specific surface area and pore size distribution according to Brunauer-Emmett-Teller (BET) theory and Barrett-Joyner-Halenda (BJH) theory, respectively. As shown in FIG. 4, the isothermal nitrogen adsorption-desorption curves of the non-porous single crystal sample and the porous single crystal sample are clearly shown, and the porous single crystal NiS is provided₂Has a larger N₂The adsorption quantity and the formed adsorption and desorption curve type conform to the curve type of the porous structure. The inset in fig. 4 is a pore size distribution curve obtained from a nitrogen adsorption test, from which it can be seen that the pore size distribution of porous single crystal particles is concentrated to 20-50 nm, which has a pore size similar to that of the silicon oxide nanospheres in the selected template, while pore size distribution cannot be tested for a non-porous sample, confirming the effectiveness of the preparation method of the metal sulfide porous single crystal.

Example 5

Porous single crystal NiS prepared by silicon oxide nanosphere (50nm) close-packed template with seed crystals preset by adding impregnation method₂(MSC-NiS₂) And non-porous single crystal NiS prepared without adding prefabricated template₂(Solid-NiS₂) As a comparison, the effect of the porous structure on the electrocatalytic oxygen production performance was investigated.

Electrocatalytic oxygen production test conditions: 4mg of the sample was first dispersed in 1mL of a 25 vol% ethanol aqueous solution, and 30. mu.L of perfluorosulfonic acid resin (Nafion) was dropped, then 10. mu.L was dropped to a rotating disk electrode having a diameter of 5mm in several times, and after natural drying, it was placed on a rotating disk electrode apparatus manufactured by PINE corporation of America at an electrode rotation speed of 1600rpm using an EC-Lab VSP 300 electrodeThe chemical workstation performs the test, and the voltage scanning speed is 5 mV/s. The test results are shown in fig. 5. As can be seen from the figure, at higher voltages, MSC-NiS₂The catalyst has higher catalytic current, which shows that the porous structure has an enhancement effect on the OER catalytic performance of the nickel-sulfur compound.

The embodiment result shows that the method for preparing the three-dimensional porous single crystal nickel disulfide by using the prefabricated template through the immersion-vulcanization method pre-seeding can effectively utilize the structure of the prefabricated template to prepare the porous single crystal particles with the template reverse structure. The prepared porous particles have high crystallinity, good single crystallinity and higher electro-catalysis oxygen generation performance. Compared with the existing method for preparing the porous monocrystalline oxide, the method for synthesizing the porous monocrystalline oxide of the metal sulfide has the advantages of simple operation and high template applicability. The method has an important reference effect on the preparation of more porous structure single crystals in the future, and has potential scale popularization value.