阅读说明：本技术 一种多孔钴/镍掺杂碳中空结构材料、其制备方法及应用 (Porous cobalt/nickel-doped carbon hollow structure material, and preparation method and application thereof ) 是由 陶孙林 刘颖雅 王安杰 王瑶 孙志超 遇治权 于 2020-12-31 设计创作，主要内容包括：本发明公开了一种多孔钴/镍掺杂碳中空结构材料、其制备方法及应用,首先以羧化聚苯乙烯纳米球为模板,利用钴/镍离子与羧酸的配位作用,将过渡金属离子锚定在羧化聚苯乙烯纳米球表面,再通过引入新的配体,在羧化聚苯乙烯纳米球表面实现金属有机骨架材料的定向组装制得PS@MOF复合微球；随后将制得的PS@MOF复合微球在氮气气氛下进行退火处理,得到钴/镍掺杂碳中空结构材料。本发明制备工艺简单,易于批量制备,且可通过调节羧化聚苯乙烯纳米球尺寸得到不同孔径的碳中空结构材料；所制得的材料具有多孔中空结构,能够作为电催化析氢反应材料,具备较高的活性以及优异的稳定性。(The invention discloses a porous cobalt/nickel-doped carbon hollow structure material, a preparation method and application thereof.A carboxylated polystyrene nanosphere is taken as a template, transition metal ions are anchored on the surface of the carboxylated polystyrene nanosphere by utilizing the coordination of cobalt/nickel ions and carboxylic acid, and then a new ligand is introduced to realize the oriented assembly of a metal organic framework material on the surface of the carboxylated polystyrene nanosphere so as to prepare a PS @ MOF composite microsphere; and then annealing the prepared PS @ MOF composite microspheres in a nitrogen atmosphere to obtain the cobalt/nickel doped carbon hollow structure material. The preparation method is simple in preparation process and easy for batch preparation, and carbon hollow structure materials with different apertures can be obtained by adjusting the size of the carboxylated polystyrene nanosphere; the prepared material has a porous hollow structure, can be used as an electrocatalytic hydrogen evolution reaction material, and has high activity and excellent stability.)

1. A preparation method of a porous cobalt/nickel-doped carbon hollow structure material is characterized by comprising the following steps: the method comprises the following steps:

1) adding the carboxylated polystyrene nanospheres and cobalt acetate tetrahydrate or nickel acetate tetrahydrate into methanol or ethanol, and carrying out ultrasonic treatment;

2) dispersing 2, 5-dihydroxy terephthalic acid in methanol or ethanol, and performing ultrasonic treatment to form a homogeneous solution;

3) slowly dripping the solution obtained in the step 1) into the solution obtained in the step 2) while stirring, stirring at room temperature after finishing dripping, and further reacting for 1-6 h;

4) after the reaction is finished, centrifugally washing until filtrate is colorless and clear, drying and calcining to obtain the porous cobalt/nickel doped carbon hollow structure material.

2. The method as claimed in claim 1, wherein in step 1), 25-100mg of carboxylated polystyrene nanospheres are added per 300-330mg of cobalt acetate tetrahydrate or nickel acetate tetrahydrate.

3. The method for preparing the porous cobalt/nickel-doped carbon hollow structure material according to claim 1, wherein in the step 2), cobalt/nickel ions and H are mixed₄The molar ratio of DOBDC is (1-4): 1.

4. the preparation method of the porous cobalt/nickel-doped carbon hollow structure material according to claim 1, wherein the reaction temperature in the step 3) is 25-35 ℃ and the reaction time is 1-6 h.

5. The method for preparing the porous cobalt/nickel-doped carbon hollow structure material as claimed in claim 1, wherein the calcination in the step 4) is performed at 500-800 ℃ for 3-5h in a nitrogen atmosphere.

6. The porous cobalt/nickel-doped carbon hollow structure material prepared by the method of any one of claims 1 to 5.

7. The porous Co/Ni-doped C hollow structure material as claimed in claim 6, wherein the valence of the Co or Ni metal doped with the material is 0, and the Co or Ni metal doped with the material has a spherical shape with a uniform size, a diameter of 350-450nm, and an inner hollow diameter of 280-320 nm.

8. Use of the porous cobalt/nickel doped carbon hollow structure material of claim 7 for electrocatalytic hydrogen evolution reactions.

Technical Field

The invention belongs to the field of catalyst preparation, relates to a preparation method of a hydrogen evolution catalyst, and particularly relates to a porous cobalt/nickel-doped carbon hollow structure material, and a preparation method and application thereof.

Background

Fossil energy remains the major energy source in the world today, and its unsustainability and various environmental problems arising from its use have made the development of renewable clean energy and technologies a trend. The hydrogen has the characteristics of good combustion performance, highest calorific value except nuclear fuel, cleanest products after combustion and the like, and is considered as an ideal substitute of future fossil energy.

The main hydrogen production technologies at present are divided into three types: chemical hydrogen production, biomass hydrogen production and water decomposition hydrogen production, which can cause the problem of carbon emission, and biomass hydrogen production is not suitable for large-scale production; hydrogen production by water splitting is the most ideal means of hydrogen production, but requires highly efficient catalysts to reduce energy consumption to ensure that a greater cathodic current density is achieved at a lower overpotential. Among them, platinum group metals and their alloys are the best electrocatalytic hydrogen evolution reaction catalysts at present because of their low fermi level and optimal hydrogen ion adsorption and desorption capabilities, but cannot be widely used as catalysts in hydrogen production due to their rarity and high cost. Therefore, the search for alternative non-noble metal catalysts has become an important part of the industrial hydrogen production field.

The metal organic framework material is a crystalline porous hybrid material, which is a material with a special pore channel structure formed by taking metal ions or metal ion clusters as coordination centers and carrying out coordination with organic ligands containing nitrogen, oxygen and the like. In recent years, electrocatalytic materials constructed by MOFs and derivatives thereof are gradually applied to the field of electrochemical energy storage and conversion, for example, Feng et al (Feng, X., et al, 2019.ACS applied Mater Interfaces 11,8018-8024) synthesizes porous rod-shaped cobalt/nickel nitride with excellent electrocatalytic performance by oxidizing MOFs and then nitridizing; liu et al (Liu, T., et al, 2019.Angew Chem Int Ed Engl 58, 4679-one 4684) synthesized cobalt phosphide-doped MOF-based electrocatalytic materials by growing MOF on carbon fiber paper and then carrying out phosphating treatment on the MOF. However, the hollow structure derivatives constructed based on the MOFs are still rarely reported, and the practical application of the MOFs is limited.

Disclosure of Invention

In order to solve the technical problems, the invention provides a porous cobalt/nickel-doped carbon hollow structure material which is prepared by synthesizing core-shell MOF by taking carboxylated polystyrene nanospheres as templates and then constructing the porous cobalt/nickel-doped carbon hollow structure material with excellent electro-catalytic performance by taking the core-shell MOF as a precursor. The method can obtain carbon hollow structure materials with different apertures by adjusting the size of the carboxylated polystyrene nanosphere; the prepared material has a porous hollow structure, can be used as an electrocatalytic hydrogen evolution reaction material, and has high activity and excellent stability.

One aspect of the present application is to provide a method for preparing a porous cobalt/nickel-doped carbon hollow structure material, which mainly comprises the following steps: using carboxylated polystyrene nanospheres (PS) as a template, anchoring transition Metal ions on the surfaces of the carboxylated polystyrene nanospheres by utilizing the coordination action of cobalt/nickel ions and carboxylic acid, and then introducing a new ligand to realize the oriented assembly of Metal-organic frameworks (MOFs) materials on the surfaces of the carboxylated polystyrene nanospheres to prepare PS MOF composite microspheres; the prepared PS @ MOF composite microspheres are annealed in a nitrogen atmosphere to obtain the cobalt/nickel doped carbon hollow structure material.

The method comprises the following specific steps:

1) carboxylated polystyrene nanospheres and cobalt acetate tetrahydrate (Co (CH)₃COO)₂·4H₂O) or nickel acetate tetrahydrate (Ni (CH)₃COO)₂·4H₂O) is added into methanol or ethanol, ultrasonic treatment is carried out, the generally preferred ultrasonic treatment time is 30-60min, and the aim is to coordinate cobalt/nickel ions with carboxyl on the nanospheres;

2) reacting 2, 5-dihydroxyterephthalic acid (H)₄DOBDC) is dispersed in methanol or ethanol, and ultrasonic treatment is carried out, wherein the generally preferred ultrasonic treatment time is 10-30min, and a homogeneous solution is formed;

3) slowly dripping the solution obtained in the step 1) into the solution obtained in the step 2) while stirring, stirring at room temperature after finishing dripping, and further reacting for 1-6 h;

4) after the reaction is finished, centrifugally washing until filtrate is colorless and clear, drying and calcining to obtain the porous cobalt/nickel doped carbon hollow structure material.

For the above technical solution, preferably, in step 1), 25-100mg of carboxylated polystyrene nanospheres are added per 300-330mg of cobalt acetate tetrahydrate or nickel acetate tetrahydrate, and the ultrasonic treatment time is longer, so that cobalt/nickel ions can coordinate with carboxyl groups on the surface of the nanospheres as much as possible.

For the above-mentioned technical solutions, it is preferable that, in step 2), the cobalt/nickel ions and H₄The molar ratio of DOBDC is (1-4): 1, the molar ratio of the two is suitably 2.6: 1.

for the above technical scheme, preferably, the reaction in the step 3) is carried out at the reaction temperature of 25-35 ℃ for 1-6 h.

For the above technical solution, preferably, the calcination in step 4) is calcination at 800 ℃ for 3-5h under a nitrogen atmosphere.

The invention also provides the porous cobalt/nickel-doped carbon hollow structure material synthesized by the preparation method. Preferably, the valence state of the cobalt or nickel doped with the material is 0, the cobalt or nickel doped with the material has a spherical shape with uniform size, the diameter is 350-450nm, and the inner hollow diameter is 280-320 nm.

In addition, the invention also provides application of the porous cobalt/nickel-doped carbon hollow structure material in the aspect of electrocatalytic hydrogen evolution reaction.

Compared with the prior art, the invention has the technical progress that:

1) the invention provides a method for preparing core-shell MOF-74 by taking carboxylated polystyrene nanospheres as templates and then preparing a porous carbon hollow structure electro-catalytic hydrogen evolution material by taking the core-shell MOF-74 as a precursor;

2) the preparation method has the advantages of simple preparation process, no high-temperature and high-pressure environment, small environmental pollution and easy batch preparation, and uses methanol or ethanol as a solvent. Meanwhile, the material obtained by the invention has good electrocatalytic hydrogen evolution performance;

3) the invention adopts the carboxylated polystyrene nanospheres as the template, and can obtain the carbon hollow structure material with different pore diameters by adjusting the size of the synthesized carboxylated polystyrene nanospheres.

Drawings

FIG. 1 is an SEM image of carboxylated polystyrene nanospheres used in the preparation of examples 1, 2, 3, 4;

FIG. 2 is a graph of TG/DTG of carboxylated polystyrene nanospheres used in the preparation of examples 1, 2, 3,4 under nitrogen atmosphere;

FIG. 3 shows carboxylated polystyrene nanospheres used in the preparation of examples 1, 2 and 3, and the PS @ MOF-74-Co, PS @ MOF-74-Ni and PS @ MOF-74-Co prepared respectively₁Ni₁XRD pattern of (a);

FIG. 4 is a FT-IR plot of carboxylated polystyrene nanospheres used in the preparation of examples 1, 2, 3,4 and the PS @ MOF-74-Co, PS @ MOF-74-Ni prepared in examples 1, 2, respectively, and the MOF-74-Co, MOF-74-Ni prepared in comparative examples 1, 2, respectively;

FIG. 5 is a TG/DTG plot of PS @ MOF-74-Co prepared in example 1 under a nitrogen atmosphere;

FIG. 6 is a SEM image of examples 1, 2, 3,4 and comparative examples 1 and 2, wherein a is MOF-74-Co prepared in comparative example 1, b is PS @ MOF-74-Co prepared in example 1, c is MOF-74-Ni prepared in comparative example 2, d is PS @ MOF-74-Ni prepared in example 2, and e is PS @ MOF-74-Co prepared in example 3₁Ni₁F is PS @ MOF-74-Co prepared in example 4, g is the porous cobalt-doped carbon hollow structure material prepared in example 1, and h is the porous nickel-doped carbon hollow structure material prepared in example 2;

FIG. 7 is XRD patterns of a porous cobalt-doped carbon hollow structure material prepared in example 1 and a cobalt-doped carbon material prepared in comparative example 1;

FIG. 8 is XRD patterns of the porous nickel-doped carbon hollow structure material prepared in example 2, the nickel-doped carbon material prepared in comparative example 2, and the porous cobalt-nickel-doped carbon hollow structure material prepared in example 3;

FIG. 9 is a TEM image of the porous cobalt-doped carbon hollow structure material prepared in example 1, wherein a, b, c and d are TEM images at different magnifications respectively;

FIG. 10 is an LSV diagram of the PS @ MOF-74-Co, porous cobalt-doped carbon hollow structure material, PS @ MOF-74-Ni, porous nickel-doped carbon hollow structure material and porous cobalt-nickel-doped carbon hollow structure material prepared in examples 1, 2 and 3, respectively.

Detailed Description

The following examples are presented to further illustrate the practice of the present invention, but the practice and protection of the present invention is not limited thereto. It is noted that the processes described below, if not specifically described in detail, are all those that can be carried out or understood by those skilled in the art with reference to the prior art. The reagents or apparatus used are not indicated to the manufacturer, and are considered to be conventional products available by commercial purchase.

Carboxylated polystyrene nanospheres used in the present application were synthesized according to the methods described in the literature (Lin, et al 2018.chemistry Select 3, 4831-4837).

Example 1

1) Weighing 0.324g of cobalt acetate tetrahydrate and 0.050g of carboxylated polystyrene nanospheres, dispersing in 50mL of methanol, and performing ultrasonic treatment for 30min to form a first solution; then 0.100g of 2, 5-dihydroxy terephthalic acid is weighed and dissolved in 20mL of methanol, and a uniform solution is formed by ultrasonic treatment to form a solution II;

2) placing the solution I on a magnetic stirrer, and dropwise adding the solution II while stirring, wherein the color of the solution is changed from white powder to brown yellow; after the dropwise addition is finished, the mixture is vigorously stirred for reaction for 2 hours, and then is centrifugally washed by methanol and absolute ethyl alcohol, and is dried in an oven at the temperature of 80 ℃ to obtain a product, namely PS @ MOF-74-Co;

3) placing PS @ MOF-74-Co in a box-type tubular furnace, introducing nitrogen for protection, heating to 600 ℃ at a flow rate of 30mL/min and a heating rate of 5 ℃/min, and calcining for 3h to obtain the target product porous cobalt-doped carbon hollow structure material.

SEM images of carboxylated polystyrene nanospheres used in example 1 are shown in fig. 1 as spheres of uniform size, approximately 400nm in diameter; as can be seen from the TG/DTG diagram of FIG. 2, the carboxylated polystyrene nanospheres are completely decomposed when the temperature reaches above 450 ℃ in the nitrogen atmosphere; the XRD pattern is shown in figure 3, and XRD diffraction peaks of the carboxylated polystyrene nanosphere are 10.4 degrees and 19.2 degrees, which are basically corresponding to the diffraction peaks of an XRD standard spectrum reported in the literature.

The XRD pattern of PS @ MOF-74-Co is shown in figure 3, and XRD diffraction peaks are at 6.8 degrees and 11.8 degrees, which substantially correspond to the diffraction peaks of the XRD standard spectrum of MOF-74 reported in the literature. As can be seen from the FT-IR characterization of FIG. 4, a Co-O bond (584 cm) was detected in PS @ MOF-74-Co^-1) C-H bond in benzene ring (889 cm)^-1And 817cm^-1) C-O bond (1200 cm)^-1And 1241cm^-1) And C ═ C bond in benzene ring (1415 cm)^-1) C ═ O bond (1559 cm)^-1) -OH bond (3423 cm)^-1) The peak of stretching vibration of the PS pellets, and the C-C bond (754 cm) in the PS pellets^-1And 699cm^-1)、-CH₂-bond (2924 cm)^-1) C-H bond (3030 cm)^-1) The stretching vibration peak of (1). TG/DTG diagram is shown in figure 5, when the temperature is raised to 124 ℃ under the nitrogen atmosphere, PS @ MOF-74-Co is approximately lost by 13 percent, and the part is residual solvent and organic ligand in the pore channel; continuing to heat to 402 ℃, losing 27% of weight of PS @ MOF-74-Co, gradually decomposing MOF-74-Co, and beginning to decompose PS at 350 ℃; the temperature is continuously increased to 552 ℃, the quality of the sample is not changed and is stabilized at 37.22 percent. And from the SEM image of fig. 6(b), the spherical morphology can be seen and the spherical diameter is increased by approximately 30nm compared to the size of the carboxylated polystyrene nanospheres; the above proves the successful synthesis of PS @ MOF-74-Co material.

An XRD pattern of the porous cobalt-doped carbon hollow structure material is shown in figure 7, and it can be seen that after annealing treatment is carried out on PS @ MOF-74-Co at 600 ℃ in a nitrogen atmosphere, an XRD diffraction peak of an obtained sample basically corresponds to a PDF #15-0806 card of Co; and as can be seen from the SEM image of fig. 6(g), the sample still maintains the spherical morphology after the annealing treatment, and in addition, from the TEM image of fig. 9, the sample can be seen to be a hollow structure, thereby proving that the porous cobalt-doped carbon hollow structure material is successfully synthesized.

The results of the electrocatalytic hydrogen evolution performance test of the PS @ MOF-74-Co and porous cobalt-doped carbon hollow structure material are shown in FIG. 10, and it can be seen that the hydrogen evolution performance of the sample before annealing treatment is poor, and even the current density is less than 10mA/cm²And the current density of the porous cobalt-doped carbon hollow structure material reaches 10mA/cm²The desired overpotential is 400 mV.

Comparative example 1

1) Weighing 0.324g of cobalt acetate tetrahydrate, dispersing in 50mL of methanol, and carrying out ultrasonic treatment for 30min to form a solution I; then 0.100g of 2, 5-dihydroxy terephthalic acid is weighed and dissolved in 20mL of methanol, and a uniform solution is formed by ultrasonic treatment to form a solution II;

2) placing the solution I on a magnetic stirrer, and dropwise adding the solution II while stirring, wherein the color of the solution is changed from pink into brown yellow; after the dropwise addition is finished, the mixture is stirred vigorously to react for 2 hours, and then is centrifugally washed by methanol and absolute ethyl alcohol, and is dried in an oven at the temperature of 80 ℃ to obtain a product, namely MOF-74-Co;

3) and (3) placing the MOF-74-Co in a box-type tubular furnace, introducing nitrogen for protection, heating to 600 ℃ for calcining for 3 hours at the flow rate of 30mL/min and the heating rate of 5 ℃/min, and obtaining the target product, namely the cobalt-doped carbon material.

In comparative example 1, the FT-IR chart of the synthesized MOF-74-Co is shown in FIG. 4, and Co-O bond (584 cm)^-1) C-H bond in benzene ring (889 cm)^-1And 817cm^-1) C-O bond (1200 cm)^-1And 1241cm^-1) And C ═ C bond in benzene ring (1415 cm)^-1) C ═ O bond (1559 cm)^-1) -OH bond (3423 cm)^-1) The stretching vibration peak of (1); and from the SEM image of FIG. 6(a), it can be seen that MOF-74-Co does not have a spherical morphology.

The XRD pattern of the cobalt-doped carbon material is shown in figure 7, and it can be seen that after the MOF-74-Co is subjected to 600 ℃ annealing treatment in the nitrogen atmosphere, the XRD diffraction peak of the obtained sample basically corresponds to the PDF #15-0806 card of Co, which proves that the cobalt-doped carbon material is successfully synthesized, but the cobalt-doped carbon material does not have a hollow structure, has scattered particles in appearance and has lower electro-catalytic hydrogen evolution performance than the cobalt-doped carbon hollow structure material.

Example 2

1) Weighing 0.324g of nickel acetate tetrahydrate and 0.075g of carboxylated polystyrene nanospheres, dispersing in 50mL of methanol, and performing ultrasonic treatment for 60min to form a solution I; then 0.200g of 2, 5-dihydroxy terephthalic acid is weighed and dissolved in 20mL of methanol, and a uniform solution is formed by ultrasonic treatment to form a solution II;

2) placing the solution I on a magnetic stirrer, and dropwise adding the solution II while stirring, wherein the color of the solution is changed from white green to yellow green; after the dropwise addition is finished, the mixture is stirred vigorously to react for 4 hours, and then is centrifugally washed by methanol and absolute ethyl alcohol, and is dried in an oven at the temperature of 80 ℃ to obtain a product, namely PS @ MOF-74-Ni;

3) placing PS @ MOF-74-Ni in a box-type tubular furnace, introducing nitrogen for protection, heating to 600 ℃ at a flow rate of 30mL/min and a heating rate of 5 ℃/min, and calcining for 3h to obtain the target product porous nickel-doped carbon hollow structure material.

In example 2, the XRD pattern of the synthesized PS @ MOF-74-Ni is shown in figure 3, and XRD diffraction peaks are at 6.8 degrees and 11.8 degrees, which substantially correspond to the diffraction peaks of the XRD standard spectrum of MOF-74 reported in the literature. As can be seen from the FT-IR characterization of FIG. 4, a Ni-O bond (545 cm) was detected in PS @ MOF-74-Ni^-1) C-H bond in benzene ring (889 cm)^-1And 817cm^-1) C-O bond (1200 cm)^-1And 1241cm^-1) And C ═ C bond in benzene ring (1415 cm)^-1) C ═ O bond (1559 cm)^-1) -OH bond (3423 cm)^-1) The peak of stretching vibration of the PS pellets, and the C-C bond (754 cm) in the PS pellets^-1And 699cm^-1)、-CH₂-bond (2924 cm)^-1) C-H bond (3030 cm)^-1) The stretching vibration peak of (1). And from the SEM image of fig. 6(d), the spherical morphology can be seen and the spherical diameter is increased by approximately 100nm compared to the size of the carboxylated polystyrene nanospheres; the PS @ MOF-74-Ni material is successfully synthesized.

The XRD pattern of the porous nickel-doped carbon hollow structure material is shown in figure 8, and it can be seen that after annealing treatment is carried out on PS @ MOF-74-Ni at 600 ℃ in a nitrogen atmosphere, the XRD diffraction peak of the obtained sample basically corresponds to the PDF #04-0850 card of Ni, and as can be seen from the SEM pattern in figure 6(h), the sample still keeps a spherical shape after the annealing treatment, thereby proving that the porous nickel-doped carbon hollow structure material is successfully synthesized.

The results of the electrocatalytic hydrogen evolution performance test of the PS @ MOF-74-Ni and porous nickel-doped carbon hollow structure material are shown in FIG. 10, and it can be seen that the hydrogen evolution performance of the sample before annealing treatment is poor, and even the current density is less than 10mA/cm²And the current density of the porous nickel-doped carbon hollow structure material reaches 10mA/cm²The desired overpotential is 532 mV.

Comparative example 2

1) Weighing 0.324g of nickel acetate tetrahydrate, dispersing in 50mL of methanol, and carrying out ultrasonic treatment for 60min to form a solution I; then 0.200g of 2, 5-dihydroxy terephthalic acid is weighed and dissolved in 20mL of methanol, and a uniform solution is formed by ultrasonic treatment to form a solution II;

2) placing the solution I on a magnetic stirrer, and dropwise adding the solution II while stirring, wherein the color of the solution is changed from blue-green to yellow; after the dropwise addition is finished, the mixture is stirred vigorously to react for 4 hours, and then is centrifugally washed by methanol and absolute ethyl alcohol, and is dried in an oven at the temperature of 80 ℃ to obtain a product, namely MOF-74-Ni;

3) and (3) placing the MOF-74-Ni in a box-type tubular furnace, introducing nitrogen for protection, heating to 600 ℃ for calcining for 3 hours at the flow rate of 30mL/min and the heating rate of 5 ℃/min, and obtaining the target product nickel-doped carbon material.

In comparative example 2, the FT-IR chart of the synthesized MOF-74-Ni is shown in FIG. 4, and Ni-O bond (545 cm) can be seen^-1) C-H bond in benzene ring (889 cm)^-1And 817cm^-1) C-O bond (1200 cm)^-1And 1241cm^-1) And C ═ C bond in benzene ring (1415 cm)^-1) C ═ O bond (1559 cm)^-1) -OH bond (3423 cm)^-1) The stretching vibration peak of (1); and from the SEM image of FIG. 6(c), it can be seen that MOF-74-Ni does not have a spherical morphology.

The XRD pattern of the nickel-doped carbon material is shown in figure 8, and it can be seen that after annealing treatment is carried out on PS @ MOF-74-Ni at 600 ℃ in a nitrogen atmosphere, the XRD diffraction peak of the obtained sample basically corresponds to the PDF #04-0850 card of Ni, which proves that the nickel-doped carbon material is successfully synthesized, but the nickel-doped carbon material does not have a hollow structure, has scattered particles in appearance, and has poor electro-catalytic hydrogen evolution performance compared with the nickel-doped carbon hollow structure material.

Example 3

1) Weighing 0.243g of cobalt acetate tetrahydrate, 0.243g of nickel acetate tetrahydrate and 0.050g of carboxylated polystyrene nanospheres, dispersing in 50mL of methanol, and performing ultrasonic treatment for 45min to form a solution I; then 0.100g of 2, 5-dihydroxy terephthalic acid is weighed and dissolved in 20mL of methanol, and a uniform solution is formed by ultrasonic treatment to form a solution II;

2) placing the first solution on a magnetic stirrer while stirringStirring and dropwise adding the solution II; after the dropwise addition is finished, the mixture is vigorously stirred for reaction for 4 hours, and then is centrifugally washed by methanol and absolute ethyl alcohol and dried in an oven at the temperature of 80 ℃ to obtain a product, namely PS @ MOF-74-Co₁Ni₁；

3) Placing PS @ MOF-74-Co in a box-type tubular furnace, introducing nitrogen for protection, heating to 600 ℃ at a flow rate of 30mL/min and a heating rate of 5 ℃/min, and calcining for 3 hours to obtain the target product porous cobalt-nickel doped carbon hollow structure material.

Example 3 Synthesis of PS @ MOF-74-Co₁Ni₁The XRD patterns of the compound are shown in figure 3, and XRD diffraction peaks are at 6.8 degrees and 11.8 degrees, which are basically corresponding to the diffraction peaks of the XRD standard spectrum of MOF-74 reported in the literature. And from the SEM image of fig. 6(e), the spherical morphology can be seen and the spherical diameter is increased by approximately 45nm compared to the size of the carboxylated polystyrene nanospheres; the above proves the successful synthesis of PS @ MOF-74-Co₁Ni₁A material.

The XRD pattern of the porous cobalt-nickel doped carbon hollow structure material is shown in figure 8, and the porous cobalt-nickel doped carbon hollow structure material can be seen in the atmosphere of nitrogen and is used for PS @ MOF-74-Co₁Ni₁After annealing at 600 ℃, XRD diffraction peaks of the obtained samples basically correspond to the PDF #15-0806 card of Co and the PDF #04-0850 card of Ni.

For the above PS @ MOF-74-Co₁Ni₁And a porous cobalt-nickel doped carbon hollow structure material are subjected to an electro-catalytic hydrogen evolution performance test, the result is shown in figure 10, and it can be seen that the hydrogen evolution performance of the sample is poor before annealing treatment, even the current density is less than 10mA/cm²And the current density of the porous cobalt-nickel doped carbon hollow structure material reaches 10mA/cm²The desired overpotential was 425 mV.

Example 4

1) Weighing 0.324g of cobalt acetate tetrahydrate and 0.100g of carboxylated polystyrene nanospheres, dispersing in 50mL of ethanol, and carrying out ultrasonic treatment for 30min to form a solution I; then 0.100g of 2, 5-dihydroxy terephthalic acid is weighed and dissolved in 20mL of ethanol, and a uniform solution is formed by ultrasonic treatment to form a solution II;

2) placing the solution I on a magnetic stirrer, and dropwise adding the solution II while stirring, wherein the color of the solution is changed from purple to brown; after the dropwise addition is finished, the mixture is stirred vigorously to react for 6 hours, and then is centrifugally washed by absolute ethyl alcohol and dried by an oven at the temperature of 80 ℃ to obtain a product, namely PS @ MOF-74-Co;

3) placing PS @ MOF-74-Co in a box-type tubular furnace, introducing nitrogen for protection, heating to 800 ℃ at a flow rate of 30mL/min and a heating rate of 5 ℃/min, and calcining for 3 hours to obtain the target product porous cobalt-doped carbon hollow structure material.

In example 4, the XRD diffraction peak of the synthesized PS @ MOF-74-Co is substantially consistent with the XRD diffraction peak position of the synthesized PS @ MOF-74-Co in example 1, and the stretching vibration peak in the FT-IR diagram is also consistent with the synthesized PS @ MOF-74-Co in example 1; and from the SEM image of FIG. 6(f), it can be seen that the spherical morphology, compared to the SEM image of the synthesized PS @ MOF-74-Co of example 1, can be found to be more uniform, less small particle MOF-74-Co growing on the surface of the carboxylated polystyrene nanospheres and having spherical diameter increased by approximately 75nm compared to the size of the carboxylated polystyrene nanospheres; the above proves the successful synthesis of PS @ MOF-74-Co material.

In the nitrogen atmosphere, after annealing treatment is carried out on PS @ MOF-74-Co at 800 ℃, the XRD diffraction peak of the obtained sample basically corresponds to the PDF #15-0806 card of Co.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and those skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.