CN110428976B

CN110428976B - Preparation method and application of Cu-Co-S-MOF nanosheet

Info

Publication number: CN110428976B
Application number: CN201910640910.9A
Authority: CN
Inventors: 蒋继波; 孙瑶馨; 陈宇凯; 王露露; 胡晓敏; 丛海山; 刘凤茹; 高丽; 常宾; 康佳玲; 唐佳斌
Original assignee: Shanghai Institute of Technology
Current assignee: Shanghai Institute of Technology
Priority date: 2019-07-16
Filing date: 2019-07-16
Publication date: 2021-09-28
Anticipated expiration: 2039-07-16
Also published as: CN110428976A

Abstract

The invention relates to a preparation method of a Cu-Co-S-MOF nanosheet, which comprises the following steps: s1: dissolving cobalt nitrate hexahydrate in deionized water to obtain a solution A, dissolving 2-methylimidazole in deionized water to obtain a solution B, mixing the solution A and the solution B, and then adding clean foamed nickel for reaction to obtain foamed nickel with Co-MOF; s2: dissolving copper nitrate hexahydrate and cobalt nitrate hexahydrate in isopropanol to obtain a mixed solution C, and adding carbon disulfide and pentamethyldiethylenetriamine into the mixed solution C to obtain a mixed solution D; s3: adding foamed nickel with Co-MOF into the mixed solution D, transferring the mixed solution D into a reaction kettle for hydrothermal reaction, and obtaining the Cu-Co-S-MOF nanosheet after the reaction is finished. Compared with the prior art, the preparation method is environment-friendly, simple in process and convenient for large-scale production, and the obtained Cu-Co-S-MOF nanosheet can obtain excellent electrochemical performance when applied to an electrode material.

Description

Preparation method and application of Cu-Co-S-MOF nanosheet

Technical Field

The invention relates to the technical field of electrochemistry and nano materials, in particular to a preparation method and application of a Cu-Co-S-MOF nanosheet.

Background

The increasing consumption of fossil fuels and the emission of greenhouse gases have a great impact on the environment, resulting in a growing global demand for sustainable energy supplies. But only sustainable energy is insufficient, and the world needs to explore an efficient, stable and environment-friendly energy storage device to improve the energy storage efficiency. Super Capacitors (SC) have received a great deal of attention as an energy storage device with high power density, long cycle life, low cost, and fast charge and discharge time, and therefore, development and utilization of renewable clean energy sources are becoming more and more important.

Electrodes prepared by conventional slurry coating techniques have two disadvantages: on one hand, the surface area is small, so that the capacity performance is limited; another aspect is that the binder used can reduce the conductivity.

The metal organic framework has a unique crystal structure and chemical diversity, and is widely applied to the fields of water splitting, fuel cells, solar cells, lithium ion batteries, stem cells, sensors, biosensors and the like. Recently, much research has focused on the design and fabrication of MOFs with tunable morphologies. However, the design and fabrication of MOFs is not a practical, or cost-effective, method, which hinders their practical application in the commercial field. To achieve greater cost effectiveness, there is a need to simplify the design and fabrication of MOFs with high electrochemical performance. In recent years, a small amount of MOFs have been reported as the SCs electrode material, but their specific capacity and rate performance are relatively low, and the preparation method is only suitable for laboratory model, so that the industrial application cannot be implemented.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method and application of a Cu-Co-S-MOF nanosheet.

A preparation method of a Cu-Co-S-MOF nanosheet comprises the following steps:

s1: dissolving cobalt nitrate hexahydrate in deionized water to obtain a solution A, dissolving 2-methylimidazole in deionized water to obtain a solution B, mixing the solution A and the solution B, stirring, adding clean foamed nickel for reaction, and drying a reaction product after the reaction is finished to obtain foamed nickel with Co-MOF;

s2: dissolving copper nitrate hexahydrate and cobalt nitrate hexahydrate in isopropanol to obtain a mixed solution C, and adding carbon disulfide and pentamethyldiethylenetriamine into the mixed solution C to obtain a mixed solution D;

s3: adding foamed nickel with Co-MOF into the mixed solution D, transferring the mixed solution D into a reaction kettle for hydrothermal reaction, and obtaining the Cu-Co-S-MOF nanosheet after the reaction is finished.

Further, the Cu-Co-S-MOF nanosheet is CuCo-bearing₂S₄Foam nickel of @ Co-MOF.

Further, an organic framework in the Cu-Co-S-MOF nanosheet is a cobalt-based metal organic framework.

Further, in the step S1, the molar ratio of cobalt nitrate hexahydrate to 2-methylimidazole is 1: 8.

further, the molar ratio of the copper nitrate hexahydrate to the cobalt nitrate hexahydrate in the mixed solution C is 1: 2.

Further, in step S3, the volume ratio of carbon disulfide to pentamethyldiethylenetriamine is 1: 8.3.

further, in step S3, the mixed solution D is obtained and then immediately placed in a reaction kettle for hydrothermal reaction at 150 ℃ for 8 hours.

The Cu-Co-S-MOF nanosheet prepared by the method can be widely applied to electrode materials.

The transition metal sulfide has higher conductivity and better redox performance than the transition metal oxide, CuCo₂S₄The method has high theoretical specific capacity and low cost, and cobalt and copper ions have strong oxidation-reduction performance, namely ternary copper cobalt sulfide (CuCo)₂S₄) The electrochemical performance of the copper sulfide or cobalt sulfide is better than that of binary metal. In addition, CuCo is low in electronegativity₂S₄Compared with Cu and Co oxides, the copper-based conductive material has excellent conductivity, higher electrocatalytic activity and higher theoretical capacity. According to the invention, MOFs is used as a template to prepare porous carbon/metal oxide, and the porous carbon/metal oxide is applied to an energy storage device.

Compared with the prior art, the invention has the following advantages and beneficial effects:

1. the invention directly synthesizes CuCo on the foam nickel₂S₄The @ Co-MOF electrode material greatly simplifies reaction steps, improves preparation efficiency, ensures that the solution generated in the preparation process is pollution-free, has high atom utilization rate in the whole preparation process and low preparation material cost, and can be used for large-scale industrial production.

2. CuCo prepared by the invention₂S₄One of the most important characteristics of @ Co-MOF is that the nanomaterial is in a three-dimensional stereo spherical floral cluster structure (see FIG. 1).

3. Prepared by the inventionCuCo₂S₄The @ Co-MOF nanosheet has high specific capacitance which can reach 950F/g.

Drawings

FIG. 1 is a CuCo solution obtained in example 1₂S₄SEM image of @ Co-MOF nanomaterial at 1 μm;

FIG. 2 is a CuCo solution obtained in example 1₂S₄SEM image of @ Co-MOF nanomaterial at 10 μm;

FIG. 3 is a CuCo solution obtained in example 1₂S₄CV diagram of @ Co-MOF nanomaterials;

FIG. 4 is a CuCo solution obtained in example 1₂S₄The GCD plot of the @ Co-MOF nanomaterials.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments.

Example 1

Firstly, growing a cobalt-based metal organic framework (Co-MOF) on foamed nickel (1cm multiplied by 1cm) by adopting a solution method: 0.05M cobalt nitrate hexahydrate was dissolved in 40ml of deionized water and designated solution A. 0.4M 2-methylimidazole was dissolved in 40ml of deionized water and designated solution B. The solution A and the solution B are quickly mixed and stirred, and then the mixture is put into clean foamed nickel to react for 4 hours at room temperature. After the reaction is finished, washing the foamed nickel with the Co-MOF by using ethanol and deionized water, and drying the foamed nickel in a drying oven at 60 ℃.

And secondly, dissolving 0.5mmol of copper nitrate hexahydrate and 1mmol of cobalt nitrate hexahydrate in 5ml of isopropanol to obtain a mixed solution C after the copper nitrate hexahydrate and the cobalt nitrate hexahydrate are completely dissolved, adding 120 mu l of carbon disulfide and 1ml of Pentamethyldiethylenetriamine (PMDTA) to obtain a mixed solution D, immersing the foamed nickel with the Co-MOF in the mixed solution D, and then quickly transferring the foamed nickel with the Co-MOF to a polytetrafluoroethylene hydrothermal kettle to perform solvothermal reaction for 150 ℃ and 8 hours. Cooling to room temperature after the reaction is finished, adding CuCo₂S₄The foamed nickel of the @ Co-MOF is taken out, washed for 3 times by deionized water and ethanol in turn, and then put into a vacuum drying oven at 60 ℃ for 12 hours.

The Chenghua CHI760e electrochemical workstation detects the material by cyclic voltammetry and constant current charging and dischargingThe specific capacitance and the cyclic stability, and cyclic voltammetry tests show that the material has excellent redox capability. The high specific surface area of the metamaterial is provided with a foundation by using an electron scanning microscope (for representing the surface microstructure of the electrode material). The specific capacitance of the electrode material of the invention reached 950F/g in 2M KOH solution and at a current density of 1A/g. As shown in FIG. 1 and FIG. 2, the electrode material is in a cluster sphere shape, the specific surface area of a three-dimensional structure is increased, the electrode material can be fully contacted with electrolyte, and ion exchange is quicker. According to the GCD curve of FIG. 4, the specific capacitance of 1Ag can be calculated^-1The specific capacitance of the capacitor (2) can reach 950F/g at the current density of (3).

Example 2

Clean foam nickel was prepared for use in the following experiments (clean foam nickel was selected as the substrate and example 1 required foam nickel with Co-MOF as the substrate). Dissolving 0.5mmol of copper nitrate hexahydrate and 1mmol of cobalt nitrate hexahydrate in 5ml of isopropanol, adding 120 mu l of carbon disulfide and 1ml of Pentamethyldiethylenetriamine (PMDTA) after the copper nitrate hexahydrate and the cobalt nitrate hexahydrate are completely dissolved, immersing clean foamed nickel in the solution, and then quickly transferring the foamed nickel into a polytetrafluoroethylene hydrothermal kettle to perform solvothermal reaction for 150 ℃ for 8 hours. Cooling to room temperature after the reaction is finished, adding CuCo₂S₄The foamed nickel is taken out, washed for 3 times by deionized water and ethanol in sequence, and then put into a vacuum drying oven at 60 ℃ for 12 hours.

The Chenhua CHI760e electrochemical workstation adopts cyclic voltammetry and constant-current charging and discharging methods to detect the specific capacitance and cyclic stability of the material, and cyclic voltammetry tests show that the material has excellent redox capability. The high specific surface area of the metamaterial is provided with a foundation by using an electron scanning microscope (for representing the surface microstructure of the electrode material). The specific capacitance of the electrode material of the invention reaches 520F/g in 2M KOH solution and at a current density of 0.5A/g.

Comparative example 1

The morphology, the synthetic material and the specific capacitance of the copper cobalt sulfide electrode material with other morphologies synthesized in the present example are shown in table 1, and it can be seen from the results that the structure synthesized in example 1 has a higher specific capacitance value under the same test environment.

TABLE 1 morphology of copper cobalt sulfide electrode materials, composite materials and specific capacitance

Reference in table 1:

[1]Guo S H,Chen W Q,Li M,et al.Effect of reaction temperature on the amorphous-crystalline transition of copper cobalt sulfide for supercapacitors[J]. Electrochimica Acta,2018,271,498-506.

[2]Lee Y H,Kang B K,Kim M S,et al.Synthesis and Characterization of Highly Uniform CuCo2S4Ball-in-Ball Hollow Nanospheres as High Performance Electrode for Supercapacitors[J].physica status solidi(a),2018,215(20):1700936.

[3]Wang T,Liu M,Ma H.Facile synthesis of flower-like copper-cobalt sulfide as binder-free faradaic electrodes for supercapacitors with improved electrochemical properties[J].Nanomaterials,2017,7(6):140.

[4]Jin C,Cui Y,Zhang G,et al.Synthesis of copper-cobalt hybrid oxide microflowers as electrode material for supercapacitors[J].Chemical Engineering Journal,2018,343: 331-339.

the embodiments described above are described to facilitate an understanding and use of the invention by those skilled in the art. It will be readily apparent to those skilled in the art that various modifications to these embodiments may be made, and the generic principles described herein may be applied to other embodiments without the use of the inventive faculty. Therefore, the present invention is not limited to the above embodiments, and those skilled in the art should make improvements and modifications within the scope of the present invention based on the disclosure of the present invention.

Claims

1. A preparation method of a Cu-Co-S-MOF nanosheet is characterized by comprising the following steps:

s1: respectively dissolving cobalt nitrate hexahydrate in deionized water to obtain a solution A, dissolving 2-methylimidazole in deionized water to obtain a solution B, mixing the solution A and the solution B, stirring, adding clean foamed nickel for reaction, and drying a reaction product after the reaction is finished to obtain foamed nickel with Co-MOF;

s3: adding foamed nickel with Co-MOF into the mixed solution D, transferring the mixed solution D into a reaction kettle for hydrothermal reaction, and obtaining Cu-Co-S-MOF nanosheets after the reaction is finished;

an organic framework in the Cu-Co-S-MOF nanosheet is a cobalt-based metal organic framework;

the Cu-Co-S-MOF nanosheet is CuCo-bearing₂S₄Foamed nickel of @ Co-MOF, wherein the Cu-Co-S-MOF nanosheet is in a three-dimensional spherical bouquet structure;

in the step S1, the molar ratio of the cobalt nitrate hexahydrate to the 2-methylimidazole is 1: 8;

the molar ratio of the copper nitrate hexahydrate to the cobalt nitrate hexahydrate in the mixed solution C is 1: 2;

in step S3, the volume ratio of carbon disulfide to pentamethyldiethylenetriamine is 1: 8.3.

2. the preparation method of the Cu-Co-S-MOF nanosheet according to claim 1, wherein in step S3, the obtained mixed solution D is immediately placed into a reaction kettle for hydrothermal reaction, the reaction temperature is 150 ℃, and the reaction time is 8 hours.

3. Use of Cu-Co-S-MOF nanoplates prepared as in claim 1 in an electrode material.