阅读说明：本技术 一种包覆Co-Co3O4异质纳米粒子的碳纳米管的制备方法及其应用 (Coated Co-Co3O4Preparation method and application of heterogeneous nano-particle carbon nano-tube ) 是由 徐林 张彬彬 李同飞 任怡平 黄龙珍 唐亚文 于 2021-08-09 设计创作，主要内容包括：本发明公开了一种包覆Co-Co-(3)O-(4)异质纳米粒子的碳纳米管的制备方法及其应用。具体方法为：在钴氰化钾的水溶液中加入壳聚糖的醋酸水溶液,超声形成溶胶,再冷冻干燥得到气凝胶；将气凝胶放入惰性气氛中,加热反应得到由碳纳米片上生长出包覆Co纳米粒子的碳纳米管的结构,之后再在空气中进行热处理,得到包覆Co-Co-(3)O-(4)异质纳米粒子的碳纳米管。本发明制备方法成本低廉,简易通用,所制得的材料为碳纳米管交联而成的三维碳管网络结构,该材料能够作为氧电催化材料以及柔性金属空气电池的空气阴极催化材料的应用,具备高的活性以及优异的稳定性能。(The invention discloses a coated Co-Co 3 O 4 A preparation method of heterogeneous nano-particle carbon nano-tube and application thereof. The specific method comprises the following steps: adding an acetic acid aqueous solution of chitosan into an aqueous solution of potassium cobaltcyanide, performing ultrasonic treatment to form sol, and performing freeze drying to obtain aerogel; putting aerogel into inert atmosphere, heating for reaction to obtain a structure of carbon nano-tube coated with Co nano-particles growing on the carbon nano-sheet, and then carrying out heat treatment in air to obtain the coated Co-Co 3 O 4 Carbon of heterogeneous nanoparticlesA nanotube. The preparation method is low in cost, simple and universal, the prepared material is a three-dimensional carbon tube network structure formed by crosslinking carbon nanotubes, and the material can be applied as an oxygen electro-catalysis material and an air cathode catalysis material of a flexible metal-air battery, and has high activity and excellent stability.)

1. Coated Co-Co₃O₄The preparation method of the carbon nano tube of the heterogeneous nano particle is characterized by comprising the following steps:

step 1, adding an acetic acid aqueous solution of chitosan into a potassium cobalt cyanide aqueous solution, forming sol after ultrasonic treatment, and obtaining aerogel through freeze drying;

step 2, heating the aerogel to 700-900 ℃ under the protection of inert atmosphere, calcining at high temperature, and reacting to obtain a multidimensional structure of the carbon nano tube coated with the Co nano particles growing on the carbon nano sheet;

step 3, heating the multidimensional structure of the carbon nano tube coated with the Co nano particles grown on the carbon nano sheet to 200-400 ℃ in the air, and calcining at high temperature to obtain the Co-coated carbon nano tube₃O₄Carbon nanotubes of heterogeneous nanoparticles.

2. The Co-Co coated of claim 1₃O₄The preparation method of the carbon nano tube of the heterogeneous nano particles is characterized in that the concentration of the potassium cobalt cyanide aqueous solution in the step 1 is 0.002-0.006mol/L, and the concentration of the chitosan acetic acid aqueous solution is 10-30 mg/mL.

3. The Co-Co coated of claim 1₃O₄The preparation method of the carbon nano tube of the heterogeneous nano particle is characterized in that the inert atmosphere in the step 2 is one or a mixture of nitrogen, argon, helium or carbon dioxide.

4. The Co-Co coated of claim 1₃O₄The preparation method of the carbon nano tube of the heterogeneous nano particles is characterized in that the heating rates in the step 2 and the step 3 are both 1-20 ℃/min, and the heat treatment time is 2-4 h.

5. Co-Co coated on the basis of the method according to any one of claims 1 to 4₃O₄Carbon nanotubes of heterogeneous nanoparticles.

6. Co-Co coating according to claim 1 or 5₃O₄The application of the carbon nano tube of the heterogeneous nano particle in the preparation of the alkaline oxygen reaction electrocatalyst.

7. Co-Co coating according to claim 1 or 5₃O₄The carbon nano tube of the heterogeneous nano particle is used as an air cathode catalyst to prepare the flexible metal-air battery.

Technical Field

The invention belongs to the technical field of oxygen catalysts, and particularly relates to a Co-coated catalyst₃O₄A preparation method of heterogeneous nano-particle carbon nano-tube and application thereof.

Background

With global consumption of fossil energy and increasing environmental pollution, the search for new renewable green energy storage and conversion methods has become an important and challenging research topic. The electrocatalytic Oxygen Reduction Reaction (ORR) and the Oxygen Evolution Reaction (OER) are used as the core part of the metal-air battery, and the electrocatalytic process is directly related to the performance of the battery. The traditional noble metal catalyst has high price, rare reserves and slow catalytic kinetics, so that the large-scale commercialization process of the new energy technology is greatly limited. Therefore, the research and development of non-noble metal catalysts with high catalytic activity and economic durability to replace noble metal catalysts is the key to the problem.

The excellent ORR and OER activity is due to the addition of metal-containing active sites on the conductive carbon substrate. In general, the interaction between the carbon support, the transition metal and the doped nitrogen in the composite plays a crucial role in forming the active site. Transition metal Co-based materials, alloys thereof and compound materials thereof have also proved to have good electrocatalytic oxygen reduction performance, and have been reported to be used for developing nano composite materials such as nanotubes, nanosheets and three-dimensional nano networks, which have considerable catalytic activity on electrocatalysis of oxygen. The one-dimensional nanotube structure is beneficial to the transmission of electrons and substances, so that the reaction rate of oxygen reduction is improved, and the three-dimensional nano network structure improves the electrocatalytic performance due to the dispersed catalytic active sites, the mutually cross-linked pore channel structure and higher mechanical stability. Therefore, the above-mentionedThe synergistic advantages are combined to synthesize the heteroatom-doped coated Co-Co₃O₄Carbon nanomaterials of heterogeneous nanoparticles are a sensible strategy. However, the synthesis processes in the prior art are complex, and the structural advantages cannot be better utilized to improve the performance of oxygen electrocatalysis.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a Co-Co coating₃O₄The preparation method of the carbon nano tube of the heterogeneous nano particle is simple and universal, has low cost, and the prepared Co-coated carbon nano tube is coated with Co-Co₃O₄The heterogeneous nanoparticle carbon nanotubes exhibit excellent activity and stability as oxygen electrocatalyst materials.

In order to solve the problems of the prior art, the invention adopts the technical scheme that:

coated Co-Co₃O₄The preparation method of the carbon nano tube of the heterogeneous nano particle comprises the following steps:

step 1, adding an acetic acid aqueous solution of chitosan into a potassium cobalt cyanide aqueous solution, forming sol after ultrasonic treatment, and obtaining aerogel through freeze drying;

step 2, heating the aerogel to 700-900 ℃ under the protection of inert atmosphere, preserving heat for 3h, and reacting after high-temperature calcination to obtain a multidimensional structure of the carbon nano tube coated with the Co nano particles growing on the carbon nano sheet;

step 3, heating the multidimensional structure of the carbon nano tube coated with the Co nano particles grown on the carbon nano sheet to 200-400 ℃ in the air, preserving the heat for 3h, and calcining at high temperature to obtain the Co-coated carbon nano tube₃O₄Carbon nanotubes of heterogeneous nanoparticles.

The improvement is that the concentration of the potassium cobalt cyanide aqueous solution in the step 1 is 0.002-0.006mol/L, and the concentration of the chitosan acetic acid aqueous solution is 10-30 mg/mL.

The improvement is that the inert atmosphere in the step 2 is one or more of nitrogen, argon, helium or carbon dioxide.

The improvement is that the heating rate in the step 2 and the heating rate in the step 3 are both 1-20 ℃/min, and the heat treatment time is 2-4 h.

The obtained product is coated with Co-Co₃O₄Carbon nanotubes of heterogeneous nanoparticles.

The above-mentioned coated Co-Co₃O₄The application of the carbon nano tube of the heterogeneous nano particle in the preparation of the alkaline oxygen reaction electrocatalyst.

The above-mentioned coated Co-Co₃O₄The carbon nano tube of the heterogeneous nano particle is used as an air cathode catalyst to prepare the flexible metal-air battery.

The reaction principle is as follows: taking potassium cobalt cyanide as a metal source and chitosan as a carbon nitrogen source, forming hydrogel by ultrasound, freeze-drying to obtain aerogel, then carrying out first-step calcination in a high-temperature inert atmosphere to obtain a structure of carbon nanotubes growing on carbon nanotubes coated with Co nanoparticles, and carrying out second-step calcination in an air atmosphere to oxidize partial simple substance Co into Co₃O₄Form Co-Co₃O₄Heterogeneous nanoparticles, excess carbon nanosheets oxidized to carbon dioxide, yielding coated Co-Co₃O₄Carbon nanotubes of heterogeneous nanoparticles. The material has regular appearance, and the one-dimensional carbon nano tube is beneficial to electron transfer and substance transmission, wherein Co and Co₃O₄Heterogeneous nanoparticles are formed, and the electrocatalytic performance of catalytic oxygen can be improved by the synergistic effect of the morphology and the components. In addition, the carbon nano tube contains a certain N element, which is more beneficial to improving the electrocatalytic activity of oxygen. Will coat with Co-Co₃O₄The carbon nano tube of the heterogeneous nano particle is assembled in the air cathode of the metal-air battery, and the metal-air battery shows good cyclic charge and discharge performance.

The invention obtains the coated Co-Co through simply mixing raw materials and then performing two-step high-temperature calcination₃O₄The carbon nano tube of the heterogeneous nano particle has a special shape, the one-dimensional carbon nano tube forms a three-dimensional network structure through crosslinking, so that the material is beneficial to electron transmission and substance transfer, and enhances the mechanical stability, and the components and the shape of the material cooperatively play a role, so that the material has higher activity.

Has the advantages that:

compared with the prior art, the Co-coated alloy of the invention₃O₄The preparation method and the application of the carbon nano tube of the heterogeneous nano particle have the following advantages:

1) Co-Co of smaller particle size formed by cobalt precursor and chitosan in high temperature calcination₃O₄The heterogeneous nano particles, the prepared product has regular appearance, and has the characteristics of excellent electrochemical activity, more catalytic active sites, good stability, one-dimensional composite structure and the like due to the existence of a heterogeneous structure, and compared with the conventional Co-based alloy material, the prepared Co-based alloy material has the advantages that the prepared Co-based alloy material has good electrochemical activity, more catalytic active sites and the like₃O₄The carbon nano tube of the heterogeneous nano particle has more excellent structural characteristics and component advantages, is an oxygen electrocatalyst material with extremely potential, and is expected to have wide application prospect in the future energy industry;

2) the catalyst material has a large specific surface area due to a three-dimensional carbon tube network structure formed by crosslinking one-dimensional carbon nanotubes, and a pore channel structure formed by the gaps of the carbon tubes can effectively promote the contact of electrolyte and the catalyst, so that the reaction is facilitated;

3) the one-dimensional carbon nanotube structure can directionally promote the rapid transmission of electrons and ions, improve the catalytic reaction rate and promote the reaction of reactants and the rapid output of products;

4) the one-dimensional carbon tube coated cobalt-based metal particles are prepared by a simple and convenient method capable of realizing large-scale production, the selected chitosan is cheap and easy to obtain, and compared with the traditional method for preparing the oxygen reduction electrocatalyst material, such as an electrodeposition method, a solvothermal method and the like, the method has the advantages of simple and easy process, low cost, simplicity in operation and capability of realizing large-scale production.

Drawings

FIG. 1 shows the Co-Co coating prepared in example 1 of the present invention₃O₄A low power SEM spectrum of carbon nanotubes of heterogeneous nanoparticles;

FIG. 2 shows the Co-Co coating prepared in example 1 of the present invention₃O₄Magnified SEM spectra of carbon nanotubes of heterogeneous nanoparticles;

FIG. 3 is a preparation of example 1 of the present inventionCoated Co-Co of₃O₄TEM spectra of carbon nanotubes of heterogeneous nanoparticles;

FIG. 4 shows the Co-Co coating prepared in example 1 of the present invention₃O₄TEM spectra of carbon nanotubes of heterogeneous nanoparticles;

FIG. 5 shows the Co-Co coating prepared in example 1 of the present invention₃O₄HRTEM spectra of carbon nanotubes of heterogeneous nanoparticles;

FIG. 6 shows the Co-Co coating prepared in example 1 of the present invention₃O₄XRD pattern of carbon nanotubes of heterogeneous nanoparticles;

FIG. 7 shows the Co-Co coating prepared in example 1 of the present invention₃O₄A Raman spectrum of the carbon nanotubes of the heterogeneous nanoparticles;

FIG. 8 shows the Co-Co coating prepared in example 1 of the present invention₃O₄N of carbon nanotubes of heterogeneous nanoparticles₂Adsorption and desorption curves;

FIG. 9 shows the Co-Co coating prepared in example 1 of the present invention₃O₄An LSV curve obtained by testing the oxygen reduction performance of the carbon nano tube of the heterogeneous nano particle in an oxygen saturated 0.1M KOH solution;

FIG. 10 shows the Co-Co coating prepared in example 1 of the present invention₃O₄An LSV curve is obtained by testing the oxygen evolution reaction performance of the carbon nano tube of the heterogeneous nano particle in a 1.0M KOH solution;

FIG. 11 shows Co-Co coating prepared in example 1 of the present invention₃O₄The carbon nano tube of the heterogeneous nano particle is used as a cathode catalyst to catalyze the open-circuit voltage curve of the flexible zinc-air battery;

FIG. 12 shows Co-Co coating prepared in example 1 of the present invention₃O₄The carbon nano tube of the heterogeneous nano particle is used as a cathode catalyst to catalyze the discharge polarization curve and the corresponding power density curve of the flexible zinc-air battery;

FIG. 13 shows the Co-Co coating prepared in example 1 of the present invention₃O₄The carbon nano tube of the heterogeneous nano particle is used as a cathode catalyst to be assembled into a flexible zinc-air battery at 1mA cm^-2Long-range cyclic charge-discharge diagram under current density.

Detailed Description

The invention will be further described with reference to specific embodiments and the accompanying drawings. Wherein, the experimental methods in the examples are all conventional methods unless otherwise specified; the reagents and materials are commercially available, unless otherwise specified.

Example 1

0.02 mmol of K₃[Co(CN)₆]Dissolved in 5 mL of deionized water, after which 1.0 mL of 20mg/mL aqueous acetic acid solution of chitosan (Mw =150000) (1vol.%, glacial acetic acid volume fraction 1% in water) was added, sonicated in an ultrasonic cell disruptor for 2 min, then allowed to stand for 20 min at-18 min^oFreezing for 12h, and drying in a freeze dryer for 24h to obtain aerogel;

heating the aerogel to 800 ℃ in an inert atmosphere by a program, keeping the temperature for 3h at the heating rate of 2 ℃/min, heating the aerogel to 300 ℃ in the air by the program for 3h at the heating rate of 2 ℃/min to obtain the coated Co-Co₃O₄Carbon nanotubes of heterogeneous nanoparticles.

Example 2

Except for K₃[Co(CN)₆]The same as example 1 except that the concentration of (1) was changed to 0.002mmol/mL and the sonication time was changed to 4 min.

Example 3

Except for K₃[Co(CN)₆]The same as example 1 except that the concentration of (1) was changed to 0.006mmol/mL and the sonication time was changed to 4 min.

Example 4

The same procedure as in example 1 was repeated, except that the concentration of the aqueous acetic acid solution of chitosan (Mw =150000) was changed to 10 mg/mL.

Example 5

The same procedure as in example 1 was repeated, except that the concentration of the aqueous acetic acid solution of chitosan (Mw =150000) was changed to 30 mg/mL.

Example 6

The same procedure as in example 1 was repeated, except that the concentration of the aqueous acetic acid solution of chitosan (Mw =150000) was changed to 25 mg/mL.

Example 7

The same procedure as in example 1 was repeated, except that the concentration of the aqueous acetic acid solution of chitosan (Mw =150000) was changed to 15 mg/mL.

Example 8

Temperature programmed to 750 ℃ under inert atmosphere^oOtherwise, the procedure is as in example 1.

Example 9

Temperature programmed to 850 ℃ under inert atmosphere^oOtherwise, the procedure is as in example 1.

Example 10

Temperature programmed to 700 ℃ under inert atmosphere^oOtherwise, the procedure is as in example 1.

Example 11

Temperature programmed to 650 ℃ under inert atmosphere^oOtherwise, the procedure is as in example 1.

Example 12

The same procedure as in example 1 was repeated, except that the temperature programming rate in the inert atmosphere was 5 ℃/min.

Comparative example 1

Co-coated Co-Co was prepared in the same manner as in example 1₃O₄Heterogeneous nano-particle carbon nanotubes, except that the temperature of calcination in air was adjusted in this comparative example.

The method specifically comprises the following steps: 0.02 mmol of K₃[Co(CN)₆]Dissolved in 5 mL deionized water, after which 1.0 mL of 20mg/mL aqueous chitosan (Mw =150000) acetic acid solution (1vol.%) was added, sonicated in a sonicator for 4min, then allowed to stand for 20 min at-18 min^oC, freezing for 12h, then drying for 24h in a freeze dryer, putting the obtained aerogel in an inert atmosphere, programming to 800 ℃, keeping the temperature for 3h at the heating rate of 2 ℃/min, programming to 200 ℃ in the air, keeping the temperature for 2h at the heating rate of 2 ℃/min, and obtaining the carbon nano tube structure coated with the Co nano particles growing on the carbon nano sheet.

Comparative example 2

Co-coated Co-Co was prepared in the same manner as in example 1₃O₄Heterogeneous nano-particle carbon nanotubes, except that the temperature of calcination in air was adjusted in this comparative example. The method specifically comprises the following steps: 0.02 mmol of K₃[Co(CN)₆]Dissolved in 5 mL deionized water, after which 1.0 mL of 20mg/mL chitosan (Mw =150000) ethyl acetate was addedPerforming ultrasonic treatment on an acid aqueous solution (1vol.%) in an ultrasonic cell crusher for 4min, standing for 20 min, freezing at-18 ℃ for 12h, drying in a freeze dryer for 24h, placing the obtained aerogel in an inert atmosphere, performing temperature programming to 800 ℃, performing heat preservation for 3h at the temperature raising rate of 2 ℃/min, performing temperature programming to 400 ℃ in air, performing heat preservation for 2h at the temperature raising rate of 2 ℃/min, and obtaining aggregated Co₃O₄And (3) nanoparticles.

The Co-Co coated Co-Co prepared in example 1 above was prepared by TEM, SEM, XRD, Raman, BET and TG routes₃O₄The carbon nanotubes of the heterogeneous nanoparticles were physically characterized. As can be seen from the SEM (FIGS. 1 and 2) and TEM (FIGS. 3 and 4) spectra, the catalyst prepared according to the method described in example 1 is Co-coated₃O₄The carbon nano-tubes of the heterogeneous nano-particles and the one-dimensional carbon nano-tubes with certain bamboo-like structures on the tube walls are mutually cross-linked and wound to form a three-dimensional network structure, so that a larger specific surface area and more active sites can be provided, and the electrolyte transmission and diffusion are facilitated. One end of the carbon nano tube is coated with Co-Co₃O₄Heterogeneous nanoparticles, FIG. 5 shows the lattice fringes of the nanoparticles, and Co can be seen₃O₄The presence of a heterogeneous interface. FIG. 6 is a Co-Co clad₃O₄Comparing the XRD pattern of the carbon nano tube of the heterogeneous nano particle with the standard pattern to obtain the diffraction peak of the carbon nano tube and Co₃O₄The standard cards of (PDF # 42-1467) and Co (PDF # 15-0806) were completely matched, and both substances were confirmed to be present in the carbon nanotubes. FIG. 7 shows the resulting coated Co-Co₃O₄The Raman spectrogram of the carbon nano tube of the heterogeneous nano particle shows that the carbon nano tube has higher graphitization degree, thereby having good conductivity and being beneficial to improving the activity of the carbon nano tube in catalyzing oxygen reduction reaction. FIG. 8 shows the resulting coated Co-Co₃O₄The carbon nano-tube of the heterogeneous nano-particle has larger BET specific surface area.

FIG. 9 is Co-Co cladding₃O₄The LSV curve obtained by testing the oxygen reduction performance of the carbon nano tube of the heterogeneous nano particles in the oxygen saturated 0.1M KOH solution has the half-wave potential of about 0.80V,indicating that the catalyst has certain oxygen reduction catalytic activity. FIG. 10 is Co-Co cladding₃O₄The LSV curve obtained by testing the oxygen evolution reaction performance of the carbon nano tube of the heterogeneous nano particle in the 1.0M KOH solution is 10 mA cm^-2The overpotential of (A) is 275 mV, which shows that the material has excellent performance of electrocatalytic oxygen evolution reaction.

Will coat with Co-Co₃O₄Heterogeneous nano-particle carbon nanotubes as air cathode catalysts for flexible zinc-air batteries (assembly references of flexible zinc-air batteries: Zhou Q, Hou S, Cheng Y, et al. Interfacial engineering Co and MnO with N, S Co-bonded carbon structural branched super structures heated high-efficiency electrochemical oxidative reduction for distribution Zn-air batteries [ J]Applied Catalysis B: Environmental, 2021, 295: 120281.) the open circuit voltage curve of fig. 11 shows it has a stable and high open circuit voltage (1.34V). As shown in FIG. 12, coated with Co-Co₃O₄The maximum power density of the heterogeneous nano-particle carbon nano-tube catalyst is 50mW cm^-2. The current density is 1mA cm during charging and discharging^-2And then, long-range cycle performance test is carried out, and the stable operation is carried out for 13.3 h. Showing a remarkably long cycle life (figure 13). These excellent properties are mainly attributed to the coating of Co-Co₃O₄The carbon nano tube of the heterogeneous nano particle has stable structure and composition. The material has wide application prospect as an oxygen electrocatalyst and an air cathode catalyst of a flexible zinc-air battery.

The above description is only a preferred embodiment of the present invention, and the scope of the present invention is not limited thereto, and any simple modifications or equivalent substitutions of the technical solutions that can be obviously obtained by those skilled in the art within the technical scope of the present invention are within the scope of the present invention.