阅读说明：本技术 一种具有类十二面体中空结构的钴镍基硒化物材料的制备方法与应用 (Preparation method and application of cobalt-nickel-based selenide material with dodecahedron-like hollow structure ) 是由 王春栋 黎建刚 于 2020-07-22 设计创作，主要内容包括：本发明属于新一代能源存储与催化领域,具体涉及一种具有类十二面体中空结构的钴镍基硒化物材料的制备方法。本发明首先采用ZIF-67为初始模板制备菱形十二面体纳米结构,随后经阳离子交换刻蚀得到包含空腔状的结构,再采用化学气相沉积法进行相转变,得到相应的金属硒化物,最后采用油浴回流法,以上述金属硒化物为基底,加入金属盐与尿素沉淀剂反应得到高性能电解水阳极端催化剂(Co,Ni)Se<Sub>2</Sub>@NiFeLDH。与现有技术相比,本发明通过采用牺牲模板法制备出新型具有类十二面体中空几何结构的含镍基硒化物界面复合材料,该材料在电催化水分解阳极端催化过程中表现出优异的电催化活性以及良好的稳定性,适于推广与应用。(The invention belongs to the field of new-generation energy storage and catalysis, and particularly relates to a preparation method of a cobalt-nickel-based selenide material with a dodecahedron-like hollow structure. The invention firstly adopts ZIF-67 as an initial template to prepare a rhombic dodecahedron nano structure, then obtains a structure containing a cavity shape by cation exchange etching, then adopts a chemical vapor deposition method to carry out phase transformation to obtain corresponding metal selenide, and finally adopts an oil bath reflux method,the metal selenide is taken as a substrate, and metal salt and urea precipitator are added to react to obtain the high-performance electrolytic water anode end catalyst (Co, Ni) Se 2 @ nifehd. Compared with the prior art, the novel nickel-based selenide interface composite material with the dodecahedron-like hollow geometric structure is prepared by adopting a sacrificial template method, and the material shows excellent electrocatalytic activity and good stability in the electrocatalytic water decomposition anode end catalysis process, and is suitable for popularization and application.)

1. A preparation method of a cobalt-nickel-based selenide material with a dodecahedron-like hollow structure is characterized by comprising the following steps:

(1) preparing a rhombic dodecahedron cobalt-based metal-organic framework structure: respectively dissolving cobalt salt and 2-methylimidazole by using a solvent, reacting, filtering and drying to obtain violet blue solid powder, namely ZIF-67;

(2) preparing cobalt-nickel-containing layered double hydroxide with a hollow structure: dispersing the ZIF-67 in absolute ethyl alcohol, adding nickel salt for reaction, filtering and drying to obtain light green solid powder, namely CoNi-LDH;

(3) preparing the cobalt-nickel bimetallic selenide with a hollow structure: uniformly mixing the CoNi-LDH and selenium powder, filling protective gas, and carrying out temperature programmed reaction to obtain black solid powder, namely (Co, Ni) Se₂；

(4) Preparing a heterojunction interface composite structure of the hollow cobalt-containing nickel-based selenide: subjecting the (Co, Ni) Se to heat treatment₂Dispersing in the mixed solution of N-methyl pyrrolidone and water, adding urea, ferric salt and nickel salt, heating in oil bath, condensing, refluxing, filtering, and drying to obtain the cobalt-nickel-based selenide material with the dodecahedron-like hollow structure, namely (Co, Ni) Se₂@NiFe LDH。

2. The method for preparing cobalt nickel-based selenide material with dodecahedron-like hollow structure according to claim 1, wherein the cobalt salt in the step (1) is sulfate, chloride or nitrate, and the solvent is at least one of methanol and ethanol.

3. The preparation method of the cobalt-nickel-based selenide material with the dodecahedron-like hollow structure according to claim 2, wherein the reaction temperature in the step (1) is 15-50 ℃, and the molar ratio of the cobalt salt to the 2-methylimidazole is 1 (0.1-10).

4. The method for preparing a cobalt-nickel based selenide material with a dodecahedron-like hollow structure according to claim 1, wherein the nickel salt in the step (2) is a sulfate, a chloride or a nitrate, and the mass ratio of the ZIF-67 to the nickel salt is 1 (2-5).

5. The method for preparing cobalt nickel-based selenide material with dodecahedron-like hollow structure according to claim 4, wherein the reaction temperature in the step (2) is 15-80 ℃, and the reaction time is 0.5-5 h.

6. The preparation method of the cobalt-nickel-based selenide material with the dodecahedron-like hollow structure as claimed in claim 1, wherein the mass ratio of CoNi-LDH to selenium powder in the step (3) is 1 (5-10); and the specific operation of the temperature programmed reaction is as follows: heating the mixture from room temperature to 350-450 ℃, maintaining the temperature for 2 hours and then cooling the mixture; wherein the heating rate is 2-5 ℃/min.

7. The method for preparing the cobalt-nickel-based selenide material with the dodecahedron-like hollow structure according to claim 1, wherein the volume ratio of N-methylpyrrolidone to water in the mixed solution obtained in the step (4) is 1 (1-5), and the mass ratio of urea to iron salt to nickel salt is 10: (0.01-1): (0.01-1).

8. The method for preparing cobalt nickel-based selenide material with dodecahedron-like hollow structure according to claim 7, wherein the reaction temperature in the step (4) is 60-100 ℃, and the reaction time is 0.5-6 h.

9. The cobalt-nickel-based selenide material with the dodecahedron-like hollow structure prepared by the method of any one of claims 1 to 8, wherein the cobalt-nickel-based selenide material has a three-dimensional hollow regular spatial structure.

10. Use of a cobalt nickel based selenide material prepared by the method of any one of claims 1 to 8 or the cobalt nickel based selenide material of claim 9 in an electrocatalytic water splitting anode terminal.

Technical Field

The invention belongs to the field of new-generation energy storage and catalysis, and particularly relates to a preparation method of a cobalt-nickel-based selenide material with a dodecahedron-like hollow structure.

Background

With the continuous progress of science and technology, the development of human socioeconomic is facing increasingly severe energy and environmental problems, which prompts people to actively explore clean renewable energy. Hydrogen is an environment-friendly and renewable resource, and is considered as a next-generation fossil fuel alternative energy source due to the advantages of high heat value, large energy density, zero pollution of combustion products, rich sources and the like.

The hydrogen production by water electrolysis is the most effective way for large-scale hydrogen preparation, however, the method is still limited by the problem of high energy consumption caused by the slow dynamic process, and the development of an efficient and low-cost electrocatalyst is a key factor for reducing the energy consumption of the process and is also an important problem in the field of water electrolysis research at the present stage.

Among many catalysts, transition metal selenide phases have good metal characteristics, and cobalt and nickel-based selenides both exhibit high catalytic activity of Oxygen Evolution Reaction (OER) at the anode end of electrolyzed water, and are considered as noble metal catalyst substituted materials. While Wang et al reported that a nickel-doped Co-based hollow dodecahedral structure was prepared by Ni ion exchange using ZIF-67 as a template, in this study, the authors indicated that the introduction of Ni resulted in CoSe due to the difference in Jahn-Teller distortion levels between Ni and Co₂The medium lattice is slightly disordered, exposing more active sites, and electrochemical tests show that the structure has excellent OER catalytic properties (electrochim. acta2017,250, 167-173).

In addition, although NiFe LDH (layered double hydroxide) has significant OER catalytic activity, the material faces the problems of easy agglomeration and poor conductivity in the practical application process, so NiFe LDH is often used in combination with other high-conductivity materials. As Feng et al in order to overcome the low conductivity of NiFe LDH, a ternary hybrid material CoSe/NiFe LDH/EG was constructed, which exhibits good OER activity by growing CoSe on graphene sheets as a substrate and further compounding NiFe LDH (Energy environ. Sci.2016,9, 478-483).

Based on the method, ZIF-67 is used as a sacrificial template, a three-dimensional hollow geometric structure is constructed by ion exchange reaction with Ni, and the electronic structure of Co-based selenide is regulated and controlled by introducing Ni doping. Further, the (Co, Ni) -containing Se is constructed by composite growth of multi-component materials₂And NiFe LDH, with the aid of (Co, Ni) Se₂The metal property of the NiFe LDH is used for improving the low conductivity defect of the NiFe LDH, and the construction of a binary heterojunction interface is realized, so that the OER catalytic property of the composite material is synergistically enhanced, and the application provides guidance for the design of a novel efficient alkaline OER electrocatalyst.

Disclosure of Invention

In view of the above, the invention aims to provide a method for preparing a cobalt-nickel-based selenide material with a dodecahedron-like hollow structure, which comprises the steps of firstly preparing a rhombic dodecahedron nanostructure by using ZIF-67 as an initial template, then performing cation exchange etching to obtain a cavity-containing structure, performing phase transformation by using a chemical vapor deposition method to obtain a corresponding metal selenide, and finally adding a metal salt and a urea precipitator to react by using the metal selenide as a substrate by using an oil bath reflux method to obtain a high-performance electrolytic water anode end catalyst (Co, Ni) Se₂@NiFe LDH。

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of a cobalt-nickel-based selenide material with a dodecahedron-like hollow structure comprises the following steps:

(1) preparing a rhombic dodecahedron cobalt-based metal-organic framework structure: respectively dissolving cobalt salt and 2-methylimidazole by using a solvent, reacting, filtering and drying to obtain violet blue solid powder, namely ZIF-67;

(2) preparing cobalt-nickel-containing layered double hydroxide with a hollow structure: dispersing the ZIF-67 in absolute ethyl alcohol, adding nickel salt for reaction, filtering and drying to obtain light green solid powder, namely CoNi-LDH;

(3) preparing the cobalt-nickel bimetallic selenide with a hollow structure: uniformly mixing the CoNi-LDH and selenium powder, filling protective gas, and carrying out temperature programmed reaction to obtain black solid powder, namely (Co, Ni) Se₂；

(4) Preparing a heterojunction interface composite structure of the hollow cobalt-containing nickel-based selenide: subjecting the (Co, Ni) Se to heat treatment₂Dispersing in the mixed solution of N-methyl pyrrolidone and water, adding urea, ferric salt and nickel salt, heating in oil bath, condensing, refluxing, filtering, and drying to obtain the cobalt-nickel-based selenide material with the dodecahedron-like hollow structure, namely (Co, Ni) Se₂@NiFeLDH。

It is worth to say that the heterojunction interface composite structure containing nickel-based selenide, which is prepared by the invention, has a reasonably designed large cavity and a surface multi-level layered nano structure. Firstly, a metal-organic framework structure is used as an initial template, a regular rhombic dodecahedron nanostructure with uniform size and good dispersibility is prepared, a cavity-shaped structure is obtained by a cation exchange etching method, then, a chemical vapor deposition method is used for phase transformation, a corresponding metal selenide is obtained, the hollow structure of the metal selenide is supported after carbonization of residual organic matters, and the three-dimensional hollow structure of the metal selenide is stably maintained; finally adopting an oil bath reflux method, taking the metal selenide as a substrate, adding metal salt and urea precipitator, and anchoring the generated ultrathin flaky NiFe LDH on (Co, Ni) Se at high temperature₂The surface is formed, thus realizing the construction of a heterojunction interface structure and finally obtaining the cobalt-nickel-based selenide material (Co, Ni) Se with a dodecahedron-like hollow structure₂@NiFe LDH。

Furthermore, compared with the prior art, the technical scheme disclosed and protected by the invention has the advantages that the novel nickel-based selenide interface composite material with the dodecahedron-like hollow geometric structure is prepared by adopting a sacrificial template method, and the material shows excellent electrocatalytic activity and good stability in the electrocatalytic water decomposition anode end catalytic process, so that the material is suitable for popularization and application.

Preferably, the cobalt salt in step (1) is sulfate, chloride or nitrate, and the solvent is at least one of methanol and ethanol.

More preferably, the reaction temperature in the step (1) is 15-50 ℃, preferably 25 ℃, and the molar ratio of the cobalt salt to the 2-methylimidazole is 1 (0.1-10), preferably 1: 4.

Preferably, the nickel salt in the step (2) is sulfate, chloride or nitrate, and the mass ratio of the ZIF-67 to the nickel salt is 1 (2-5), preferably 1: 2.5.

Further preferably, the reaction temperature in the step (2) is 15-80 ℃, the preferred reaction temperature is 25 ℃, the reaction time is 0.5-5 h, and the preferred reaction time is 5 h.

Preferably, the mass ratio of the CoNi-LDH to the selenium powder in the step (3) is 1 (5-10); and the specific operation of the temperature programmed reaction is as follows: heating the mixture from room temperature to 350-450 ℃, maintaining the temperature for 2 hours and then cooling the mixture; wherein the heating rate is 2-5 ℃/min.

Further preferably, the mass ratio of the CoNi-LDH to the selenium powder in the step (3) is 1: 5; and the specific operation of the temperature programmed reaction is as follows: heating to 350 ℃ from room temperature, maintaining for 2h, and cooling; wherein the heating rate is 3 ℃/min.

Preferably, the volume ratio of the N-methyl pyrrolidone to the water in the mixed solution in the step (4) is 1 (1-5), and preferably the volume ratio is 1:5, the mass ratio of the urea to the ferric salt to the nickel salt is 10: (0.01-1): (0.01-1), and the preferable mass ratio is 9: 0.013: 0.042.

further preferably, the reaction temperature in the step (4) is 90 ℃ and the reaction time is 6 h.

The invention also claims the cobalt-nickel-based selenide material with the dodecahedron-like hollow structure prepared by the method, and the cobalt-nickel-based selenide material has a three-dimensional hollow regular three-dimensional structure.

The invention also aims to protect the application of the cobalt-nickel-based selenide material prepared by the method in an electrocatalytic water decomposition anode terminal.

The cobalt-nickel-based selenide material shows excellent electrocatalytic activity and good stability in the electrocatalytic water decomposition anode end catalysis process, and is suitable for market popularization and application.

Compared with the prior art, the cobalt-nickel-based selenide material with the dodecahedron-like hollow structure, the preparation method and the application thereof disclosed by the invention have the following beneficial effects:

1) the invention adopts ZIF-67 as an initial template, the preparation process of the material is simple, the raw materials are cheap, the product structure is uniform, the related solvent can be recycled, and the material is suitable for large-scale production.

2) The cobalt-nickel-based selenide material prepared by the invention has two transition metal compound components, and a heterojunction interface structure formed by the two components is effectively utilized, thereby being beneficial to synergistically enhancing the whole catalytic activity of the cobalt-nickel-based selenide material.

3) The cobalt-nickel-based selenide catalytic material prepared by the invention has a three-dimensional hollow regular three-dimensional structure, and is endowed with unique physicochemical characteristics due to the characteristics of high specific surface area and large cavity, and the structure is not only favorable for full contact between a catalyst and electrolyte and rapid transfer of charges, but also effectively releases stress in the catalytic process.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

FIG. 1 is a schematic flow chart of a preparation process of a cobalt nickel based selenide electrolytic water catalytic material with a hollow configuration provided by an embodiment of the invention;

FIG. 2 is an XRD pattern of a hollow configuration cobalt nickel based selenide composite material and its individual components before compounding prepared by an embodiment of the invention;

fig. 3 is an SEM image (fig. 3a) and a TEM image (fig. 3b) of a cobalt nickel based selenide composite material with a hollow configuration prepared by an example of the present invention;

fig. 4 is BET (fig. 4a) and BJH graphs (fig. 4b) of a cobalt nickel-based selenide composite material with a hollow configuration prepared by an embodiment of the present invention;

FIG. 5 is a comparison graph of linear sweep voltammetry polarization curves of a hollow configuration cobalt nickel-based selenide composite catalytic material prepared by an embodiment of the invention and an intermediate product in the process

FIG. 6 shows a hollow cobalt-nickel selenide composite catalytic material and a commercial catalyst RuO prepared by the embodiment of the invention₂Linear sweep voltammetric polarization plot of (a).

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the specification, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The embodiment of the invention discloses a preparation method of a cobalt-nickel-based selenide material with a dodecahedron-like hollow structure, which comprises the following steps:

(1) preparing a rhombic dodecahedron cobalt-based metal-organic framework structure: respectively dissolving cobalt salt and 2-methylimidazole by using a solvent, reacting, filtering and drying to obtain violet blue solid powder, namely ZIF-67;

(2) preparing cobalt-nickel-containing layered double hydroxide with a hollow structure: dispersing ZIF-67 in absolute ethyl alcohol, adding nickel salt for reaction, filtering and drying to obtain light green solid powder, namely CoNi-LDH;

(3) preparing the cobalt-nickel bimetallic selenide with a hollow structure: uniformly mixing CoNi-LDH and selenium powder, filling protective gas, and performing temperature programmed reaction to obtain black solid powder, namely (Co, Ni) Se₂；

(4) Preparing a heterojunction interface composite structure of the hollow cobalt-containing nickel-based selenide: mixing (Co, Ni) Se₂Dispersing in the mixed solution of N-methyl pyrrolidone and water, adding urea, ferric salt and nickel salt, heating in oil bath, condensing, refluxing,filtering and drying to obtain the cobalt-nickel-based selenide material with the dodecahedron-like hollow structure, namely (Co, Ni) Se₂@NiFe LDH。

In order to further optimize the technical scheme, the cobalt salt in the step (1) is sulfate, chloride or nitrate, and the solvent is at least one of methanol and ethanol.

In order to further optimize the technical scheme, the reaction temperature in the step (1) is 15-50 ℃, the preferable reaction temperature is 25 ℃, the molar ratio of the cobalt salt to the 2-methylimidazole is 1 (0.1-10), and the preferable molar ratio is 1: 4.

In order to further optimize the technical scheme, the nickel salt in the step (2) is sulfate, chloride or nitrate, and the mass ratio of the ZIF-67 to the nickel salt is 1 (2-5), preferably 1:2.51: 2.5.

In order to further optimize the technical scheme, the reaction temperature in the step (2) is 15-80 ℃, the preferable reaction temperature is 25 ℃, the reaction time is 0.5-5 h, and the preferable reaction time is 5 h.

In order to further optimize the technical scheme, the mass ratio of the CoNi-LDH to the selenium powder in the step (3) is 1 (5-10); and the specific operation of the temperature programmed reaction is as follows: heating the mixture from room temperature to 350-450 ℃, maintaining the temperature for 2 hours and then cooling the mixture; wherein the heating rate is 2-5 ℃/min.

Further, the mass ratio of the CoNi-LDH to the selenium powder in the step (3) is 1: 5; and the specific operation of the temperature programmed reaction is as follows: heating to 350 ℃ from room temperature, maintaining for 2h, and cooling; wherein the heating rate is 3 ℃/min.

In order to further optimize the technical scheme, the volume ratio of the N-methyl pyrrolidone to the water in the mixed solution in the step (4) is 1 (1-5), and preferably 1:5, the mass ratio of the urea to the ferric salt to the nickel salt is 10: (0.01-1): (0.01-1), and the preferable mass ratio is 9: 0.013: 0.042.

in order to further optimize the technical scheme, the reaction temperature in the step (4) is 90 ℃, and the reaction time is 6 hours.

Wherein, the attached figure 1 is a schematic flow chart of the preparation process of the hollow cobalt nickel base selenide electrolytic water catalytic material. As shown in figure 1, the invention firstly adopts ZIF-67 as an initial template to prepare a rhombic dodecahedron nano structure, then obtains a structure containing a cavity shape through cation exchange etching, then adopts a chemical vapor deposition method to carry out phase transformation to obtain corresponding metal selenide, and finally adopts an oil bath reflux method to obtain the high-performance electrolytic water anode end catalyst (Co, Ni) Se through adding metal salt and a urea precipitator into the metal selenide which is used as a substrate to react₂@NiFe LDH。

The technical solution of the present invention is further described below with reference to specific examples, but the content of the present invention is not limited to the following examples.