Molybdenum disulfide with three-dimensional hierarchical pore structure and preparation method and application thereof
阅读说明：本技术 一种三维多级孔结构二硫化钼及其制备方法与应用 (Molybdenum disulfide with three-dimensional hierarchical pore structure and preparation method and application thereof ) 是由 邓德会 郑智龙 胡景庭 孟祥宇 于 2019-04-28 设计创作，主要内容包括：本发明公开了一种三维多级孔结构二硫化钼的制备方法。具体地说,该方法首先制备多种尺度的模板,然后将钼基化合物与模板充分混匀后,在一定温度下与含硫化合物反应,最后经过溶液处理后,抽滤干燥得到目标产物。该方法所制备的材料具有完整的三维多级孔结构,无团簇,无坍塌现象,其孔壁由二硫化钼纳米片阵列所构成。所用模板种类和孔道尺度易于调变。该材料用于电催化析氢反应具有优异的活性。本方法是三维多级孔结构二硫化钼的普适方法,具有简单,易于操作的特点。(The invention discloses a preparation method of molybdenum disulfide with a three-dimensional hierarchical pore structure. Specifically, the method comprises the steps of firstly preparing templates with various scales, then fully and uniformly mixing a molybdenum-based compound and the templates, reacting the molybdenum-based compound and a sulfur-containing compound at a certain temperature, finally carrying out solution treatment, and carrying out suction filtration and drying to obtain a target product. The material prepared by the method has a complete three-dimensional hierarchical pore structure, no cluster and no collapse phenomenon, and the pore wall of the material is formed by a molybdenum disulfide nanosheet array. The type of the template and the size of the pore channel are easy to be modulated. The material has excellent activity when being used for electrocatalytic hydrogen evolution reaction. The method is a universal method for molybdenum disulfide with a three-dimensional hierarchical pore structure, and has the characteristics of simplicity and easiness in operation.)
1. A three-dimensional molybdenum disulfide material is characterized in that the molybdenum disulfide material is of a three-dimensional hierarchical pore structure; the hierarchical pore structure is a structure comprising at least two pore sizes; the pore wall of the pore channel is composed of a molybdenum disulfide nanosheet array.
2. The molybdenum disulfide material of claim 1, wherein the hierarchical pore structure is mesoporous, macroporous, or microporous of at least two pore sizes; or the hierarchical pore structure is micropore-mesopore, micropore-macropore, mesopore-macropore, micropore-mesopore-macropore.
3. The method of preparing a three-dimensional molybdenum disulfide material of claim 1, comprising the steps of:
(1) Selecting a pore template with the size consistent with that of the pore in claim 1, ultrasonically dispersing the pore template in a solvent A, stirring the mixture at the temperature of 25-100 ℃ for 1-48 hours, drying and grinding the mixture to obtain a template A;
(2) uniformly mixing the template A and the molybdenum-based compound in the step (1) in a solvent B, stirring for 1-48 h at 25-100 ℃, drying to obtain a solid A, then mixing the solid A and a sulfur-containing compound under the protection of inert gas, transferring to a high-pressure reaction kettle, and keeping at 100-600 ℃ for 1-24 h to obtain a product B;
(3) and (3) transferring the product B obtained in the step (2) to a solution from which the template agent is removed, sealing, standing for 2-24 hours, washing, and drying to obtain the molybdenum disulfide material with the three-dimensional hierarchical pore structure.
4. The preparation method according to claim 3, wherein the pore channel template in step (1) is polystyrene, nano alumina, cerium oxide, silicon dioxide, carbon nanotube, titanium dioxide and molecular sieve; the particle size of the polystyrene is 100-600 nm; the particle size of the nano alumina is 10-200 nm; the particle size of the cerium oxide is 30-100 nm; the particle size of the silicon dioxide is 1-600 nm; the size of the pore channel of the carbon nano tube is 1.5-200 nm; the particle size of the titanium dioxide is 10-80 nm; the size of the pore channel of the molecular sieve is 0.5-50 nm.
5. The preparation method according to claim 3, wherein when the pore template added in the step (1) is two pore templates with different sizes, the mass ratio of the pore template with a larger size to the pore template with a smaller size is 20: 1-15; when the pore templates added in the step (1) are pore templates with more than two sizes, the mass ratio of the pore template with the larger size to the pore template with the relatively smaller size in any two pore templates is 20: 1-10.
6. The production method according to claim 3,
the ultrasonic time in the step (1) is 1-8 h;
in the step (1), the solvent A is at least one of water, acetone, methanol, ethanol, ammonia water, toluene, acetonitrile and ethylene glycol;
in the step (1), the drying time is 4-16 h, and the drying temperature is 25-120 ℃;
the grinding time in the step (1) is 0.1-0.5 h.
7. The production method according to claim 3,
the molybdenum-based compound in the step (2) is at least one of molybdenum trioxide, sodium molybdate, phosphomolybdic acid, molybdenum chloride, potassium molybdate, ammonium tetrathiomolybdate, molybdenum acetate, ammonium molybdate, molybdenum ethoxide, molybdenum oxalate, molybdenum pentabromide, molybdenum acetylacetonate, molybdenum hexacarbonyl, molybdenum phosphide and molybdenum bromide; the mass ratio of molybdenum atoms in the molybdenum-based compound to the total mass of the pore channel template is 1: 1-100;
The mixing in the step (2) is ultrasonic dispersion mixing, and the ultrasonic time is 0.5-6 h;
in the step (2), the solvent B is at least one of water, acetone, methanol, ethanol, ammonia water, ethylene glycol, N-dimethylformamide, toluene, acetonitrile, ethylenediamine, chloroform, formic acid and diethyl ether;
the drying in the step (2) is vacuum drying or normal pressure drying, the drying temperature is 25-120 ℃, and the drying time is 4-24 hours;
the inert gas in the step (2) is at least one of nitrogen, argon or helium;
the sulfur-containing compound in the step (2) is at least one of sulfur powder, carbon disulfide, thioacetamide, dimethyl sulfoxide, thiourea, butyl mercaptan, ammonium thiocyanate, potassium thiocyanate, sodium sulfide, potassium sulfide, ammonium tetrathiomolybdate and sodium sulfite; the molar ratio of the sulfur atoms in the sulfur-containing compound to the molybdenum atoms in the molybdenum source is 1: 10-500: 1.
8. The production method according to claim 3,
the solution for removing the template agent in the step (3) is at least one of hydrofluoric acid solution, sodium hydroxide solution, potassium hydroxide solution, ammonia water solution, hydrochloric acid solution and sulfuric acid solution; the concentration of the hydrofluoric acid solution, the sodium hydroxide solution, the potassium hydroxide solution, the ammonia water solution, the hydrochloric acid solution and the sulfuric acid solution is 5-70 wt%
The washing in the step (3) is carried out in ultrapure water and ethanol until the solution is neutral;
in the step (3), the drying temperature is 25-150 ℃, and the drying time is 6-24 h.
9. Use of the three-dimensional molybdenum disulfide material according to claim 1 or the three-dimensional molybdenum disulfide material obtained by the preparation method according to any one of claims 3 to 8 in an electrocatalytic hydrogen evolution reaction.
Technical Field
The invention belongs to the field of nano two-dimensional materials, and particularly relates to molybdenum disulfide with a three-dimensional hierarchical pore structure, and a preparation method and application thereof.
Background
Two-dimensional molybdenum disulfideDue to its unique structure and electronic properties, it has attracted extensive attention in the field of catalysis, including electrocatalysis, photocatalysis and traditional catalysis. Meanwhile, the molybdenum disulfide has the advantages of large natural reserve, low price, excellent performance and the like, so that the molybdenum disulfide is expected to be a substitute of a noble metal hydrogen evolution electrocatalyst. Currently, the hydrogen evolution active sites of molybdenum disulfide are mainly derived from their small number of marginal sulfur sites, whereas their large number of in-plane sulfur sites are relatively inert (b.hinnemann, j.k).
Disclosure of Invention
The invention provides a preparation method of molybdenum disulfide with a three-dimensional hierarchical pore structure. According to the method, the molybdenum disulfide material with the three-dimensional hierarchical pore structure is effectively constructed by reasonably regulating and controlling the multi-template agent, and has excellent activity when being used for the electrocatalytic hydrogen evolution reaction. The template adopted by the method comprises two scales or more than two scales, a multi-level pore structure can be formed after the template agent is removed, and the structure can be a multi-scale mesopore, multi-scale macropore, multi-scale micropore, micropore-mesopore, micropore-macropore, mesopore-macropore and micropore-mesopore-macropore structure, and the pore wall of each single pore is composed of a molybdenum disulfide nanosheet array. The method is easy to operate, has wide application range and is suitable for constructing other two-dimensional material structures. The material has wide application prospect in the fields of electro-catalysis, photocatalysis, energy storage and conversion and the like.
The technical scheme of the invention is as follows: the invention provides a molybdenum disulfide material with a three-dimensional hierarchical pore structure, which is molybdenum disulfide with a structure at least comprising two pore canal sizes; the pore wall of the pore channel is composed of a molybdenum disulfide nanosheet array.
Preferably, in the molybdenum disulfide material with the three-dimensional hierarchical pore structure, "two" of the two pore sizes can refer to two sizes in the same pore type (micropore, mesopore and macropore), and can also refer to two pore types; the hierarchical pore structure is mesopores with at least two sizes, macropores with at least two sizes or micropores with at least two sizes; or the hierarchical pore structure is microporous with at least one pore size and mesoporous with one pore size, microporous with at least one pore size and macroporous with at least one pore size, mesoporous with at least one pore size and macroporous with at least one pore size, microporous with at least one pore size and mesoporous with at least one pore size and macroporous with at least one pore size.
The invention also provides a preparation method of the molybdenum disulfide with the three-dimensional hierarchical pore structure, which is characterized by comprising the following steps:
(1) selecting a pore template with the size consistent with that of the pore in claim 1, ultrasonically dispersing the pore template in a solvent A, stirring the mixture at the temperature of 25-100 ℃ for 1-48 hours, drying and grinding the mixture to obtain a template A;
(2) uniformly mixing the template A and the molybdenum-based compound in the step (1) in a solvent B, stirring for 1-48 h at 25-100 ℃, drying to obtain a solid A, then mixing the solid A and a sulfur-containing compound under the protection of inert gas, transferring to a high-pressure reaction kettle, and keeping at 100-600 ℃ for 1-24 h to obtain a product B;
(3) And (3) transferring the product B obtained in the step (2) to a solution from which the template agent is removed, sealing, standing for 2-24 hours, washing, and drying to obtain the molybdenum disulfide material with the three-dimensional hierarchical pore structure.
Based on the above technical scheme, preferably, the preparation method in step (1) is characterized in that the pore template in step (1) is polystyrene, nano alumina, cerium oxide, silicon dioxide, carbon nanotube, titanium dioxide and molecular sieve; the particle size of the polystyrene is 100-600 nm; the particle size of the nano alumina is 10-200 nm; the particle size of the cerium oxide is 30-100 nm; the particle size of the silicon dioxide is 1-600 nm; the size of the pore channel of the carbon nano tube is 1.5-200 nm; the particle size of the titanium dioxide is 10-80 nm; the size of the pore channel of the molecular sieve is 0.5-50 nm.
Based on the technical scheme, preferably, when the pore template added in the step (1) is pore templates with two different sizes, the mass ratio of the pore template with the larger size to the pore template with the smaller size is 20: 1-15; when the pore templates added in the step (1) are pore templates with more than two sizes, the mass ratio of the pore template with the larger size to the pore template with the relatively smaller size in any two pore templates is 20: 1-10.
Based on the technical scheme, preferably,
the ultrasonic time in the step (1) is 1-8 h;
in the step (1), the solvent A is at least one of water, acetone, methanol, ethanol, ammonia water, toluene, acetonitrile and ethylene glycol;
in the step (1), the drying time is 4-16 h, and the drying temperature is 25-120 ℃;
the grinding time in the step (1) is 0.1-0.5 h.
Based on the technical scheme, preferably,
the molybdenum-based compound in the step (2) is at least one of molybdenum trioxide, sodium molybdate, phosphomolybdic acid, molybdenum chloride, potassium molybdate, ammonium tetrathiomolybdate, molybdenum acetate, ammonium molybdate, molybdenum ethoxide, molybdenum oxalate, molybdenum pentabromide, molybdenum acetylacetonate, molybdenum hexacarbonyl, molybdenum phosphide and molybdenum bromide; the mass ratio of molybdenum atoms in the molybdenum-based compound to the total mass of the pore channel template is 1: 1-100;
the mixing in the step (2) is ultrasonic dispersion mixing, and the ultrasonic time is 0.5-6 h;
in the step (2), the solvent B is at least one of water, acetone, methanol, ethanol, ammonia water, ethylene glycol, N-dimethylformamide, toluene, acetonitrile, ethylenediamine, chloroform, formic acid and diethyl ether;
the drying in the step (2) is vacuum drying or normal pressure drying, the drying temperature is 25-120 ℃, and the drying time is 4-24 hours;
The inert gas in the step (2) is at least one of nitrogen, argon or helium;
the sulfur-containing compound in the step (2) is one or more than two of sulfur powder, carbon disulfide, thioacetamide, dimethyl sulfoxide, thiourea, butyl mercaptan, ammonium thiocyanate, potassium thiocyanate, sodium sulfide, potassium sulfide, ammonium tetrathiomolybdate and sodium sulfite; the molar ratio of sulfur atoms in the sulfur-containing compound to molybdenum atoms in the molybdenum source is 1: 10-500: 1;
based on the technical scheme, preferably,
the solution for removing the template agent in the step (3) is at least one of hydrofluoric acid solution, sodium hydroxide solution, potassium hydroxide solution, ammonia water solution, hydrochloric acid solution and sulfuric acid solution; the concentration of the hydrofluoric acid solution, the sodium hydroxide solution, the ammonia water solution, the potassium hydroxide solution, the sulfuric acid solution and the hydrochloric acid solution is 5-70 wt%
The washing in the step (3) is carried out for multiple times in ultrapure water and ethanol until the solution is neutral;
in the step (3), the drying temperature is 25-150 ℃, and the drying time is 6-24 h.
The invention also provides the application of the molybdenum disulfide material with the three-dimensional hierarchical pore structure or the molybdenum disulfide material with the three-dimensional hierarchical pore structure obtained by the preparation method in an electrocatalytic hydrogen evolution reaction, and the molybdenum disulfide material with the three-dimensional hierarchical pore structure has good activity and stability.
Advantageous effects
1. The molybdenum disulfide material with the three-dimensional hierarchical pore structure prepared by the invention has a pore channel structure with various scales, so that the specific surface area can be greatly improved, and the mass transfer rate of substances in the catalyst can be improved; molybdenum disulfide forms a regular nanosheet array on the hole wall, has rich active side sites, and can greatly improve the number of active sites; the three-dimensional structure ensures that the molybdenum disulfide is not easy to agglomerate and deactivate, and is beneficial to prolonging the service life of the catalyst.
2. The prepared molybdenum disulfide material with the three-dimensional hierarchical pore structure has rich types of multi-scale pore channel templates and wide selectable scale range, and the addition amount of the template agents with different sizes and the mixed form of the template agent, a molybdenum source and a sulfur source are favorable for the stability of the formed pore channel structure, are not easy to collapse and can be suitable for reactions without systems.
3. The prepared molybdenum disulfide material with the multi-three-dimensional hierarchical pore structure is high in hydrogen evolution activity by electrocatalysis and stable in catalyst.
4. The template required by the preparation material is wide in source, can realize macro preparation, and is easy for large-scale production.
Drawings
FIG. 1 is a Transmission Electron Microscope (TEM) image of a sample of example 1.
FIG. 2 is a High Resolution Transmission Electron Microscopy (HRTEM) image of the sample of example 1.
FIG. 3 is a Transmission Electron Microscope (TEM) image of a sample of example 2.
FIG. 4 is a High Resolution Transmission Electron Microscopy (HRTEM) image of the sample of example 2.
FIG. 5 is a Scanning Electron Microscope (SEM) image of a sample of example 3.
FIG. 6 is a Transmission Electron Microscopy (TEM) image of a sample of example 4.
FIG. 7 is a Transmission Electron Microscope (TEM) image of a sample of example 5.
FIG. 8 is a graph of pore size distribution for the sample of example 1 versus the sample of comparative example 1.
FIG. 9 is a graph showing the results of measuring the electrocatalytic hydrogen evolution activity in examples 10 and 11.
Detailed Description
The whole material preparation process is described in detail by the following examples, but the scope of the claims of the present invention is not limited by these examples. Meanwhile, the embodiments only give some conditions for achieving the purpose, but do not mean that the conditions must be satisfied for achieving the purpose.