CN110482480B - Cobalt-nickel bimetallic hydroxyl phosphite rod-like crystal array film and preparation method thereof - Google Patents

Abstract

The invention discloses a cobalt-nickel bimetallic hydroxyl phosphite rodlike crystal array film and a preparation method thereof. Dissolving nickel nitrate hexahydrate, cobalt nitrate hexahydrate and sodium hypophosphite in deionized water, and adding N, N-dimethylacetamide; soaking the pre-cleaned activated carbon fiber in the prepared solution, and carrying out sealed reaction in a reaction kettle at the temperature of 140-160 ℃ for 10-20 h; after the reaction kettle is naturally cooled to normal temperature, taking out the activated carbon fiber, repeatedly cleaning the activated carbon fiber by absolute ethyl alcohol and deionized water, drying the activated carbon fiber at 60 ℃ for 8 hours to obtain compact and uniform M on the surface of the activated carbon fiber ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M = Ni + Co) rod-like crystal array film. The rod-like crystal array film obtained by the invention has the advantages of simple and safe preparation method, uniform and compact array crystal, stable and uniform surface performance, and can be applied to the fields of novel energy storage, catalysis and sensing.

Description

A kind of cobalt-nickel bimetallic hydroxyphosphite rod-shaped crystal array film and its preparation method

technical field

The invention relates to a crystal array film with a porous fiber material as a base and a preparation method thereof, in particular to a cobalt-nickel bimetallic hydroxy phosphite rod-shaped crystal array film with an activated carbon fiber as the base and a preparation method thereof.

Background technique

Transition metal hydroxyphosphites M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M = Zn, Ni or Co) are a new type of inorganic materials, which are highly efficient in adsorption due to their diverse stoichiometric relationships and rich structural chemical properties. , catalysis and energy storage have broad potential applications [MD Marcos et al, J. Solid State Chem., 107(1993), 250–257; MD Marcos et al, Chem. Mater., 5(1993), 121–128 .]. It is well known that the properties of materials are largely dependent on the size and morphology of the materials. The study found that the ordered structure of transition metal hydroxy phosphites showed more excellent electrical and optical properties. Notably, transition metal hydroxyphosphites have begun to attract attention as effective cathode materials for a new generation of high-performance supercapacitors due to their high specific capacitance, cycling stability, and fast charge-discharge capability.

Traditional supercapacitors use a coating method to uniformly coat active materials, conductive agents (acetylene black), binders, etc. on the surface of the current collector to form electrodes. This electrode fabrication method is suitable for the application of powder active materials, but is limited to process stability and is not convenient for recycling. In contrast, by depositing the electrochemically active material in the form of a thin film on the surface of the current collector, a binder-free electrode can be obtained, which provides the possibility for efficient electron transport between the active material and the current collector, and is expected to improve the electrode performance. At present, M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Zn, Ni or Co) reported in the literature are all powder materials, and most of them are single metal hydroxyphosphites. A report on thin-film materials of salt rod-like crystal arrays.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a cobalt-nickel bimetallic hydroxyphosphite rod-shaped crystal array film and a preparation method thereof (which can also be expressed as: a M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-shaped Crystal array thin film and preparation method thereof). The preparation method makes full use of the abundant pore structure on the surface of activated carbon fibers, which provides a large amount of nucleation and crystallization for the heterogeneous nucleation and crystallization of M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-like crystal array films on the surface of activated carbon fibers. The core center, combined with the adjustment of reactant concentration, reaction time and reactant concentration ratio, makes M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) crystals preferentially crystallize on the surface of activated carbon fibers, followed by anisotropic growth A rod-like shape is formed.

Based _on the characteristics _of the hydrothermal reaction and the crystal growth principle, and the comprehensive action of various reaction parameters, the present invention establishes a _{stable hydrothermal} reaction system. The nucleation environment, growth orientation and crystallization rate of =Ni+Co) crystals can be precisely controlled, and the M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-like crystals that contribute to anisotropic growth characteristics in activated carbon fibers A dense and uniform array of thin film layers is formed on the surface.

The steps of the technical solution adopted in the present invention are as follows:

1. A cobalt-nickel bimetallic hydroxyphosphite rod-shaped crystal array film, the M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-shaped crystals have a diameter of 500 nanometers to 1 micron, and are dense in the form of arrays arranged to form a thin film.

2. A preparation method of a cobalt-nickel bimetallic hydroxyphosphite rod-shaped crystal array film, the steps of which are as follows:

1) Dissolve nickel nitrate hexahydrate, cobalt nitrate hexahydrate and sodium hypophosphite in deionized water at a molar concentration ratio of 1:1:2, wherein the total molar concentration of nickel ions and cobalt ions is 0.10 mol/L-0.20 mol/ liters, stirring to obtain a homogeneous solution;

2) Add N,N-dimethylacetamide to the above solution, the ratio of volume to volume of deionized water is 1:1, and continue to stir to obtain a uniform solution;

3) Immerse the pre-cleaned activated carbon fibers in the solution of step 2) for 5 hours;

4) The solution of step 3), together with the activated carbon fibers, are reacted together at 140 ℃ ~ 160 ℃ for 10 h ~ 20 h.

5) Cool the reaction kettle after the reaction in step 4) to room temperature naturally, take out the activated carbon fiber, repeatedly wash it with absolute ethanol and deionized water three times, and dry it at 60 °C for 8 h to obtain dense and uniform on the surface of the activated carbon fiber. M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-like crystal array thin film.

The activated carbon fiber is an activated carbon fiber obtained by heat treatment of natural cotton fiber at 1000° C. for 1 h under a nitrogen atmosphere.

The beneficial effects that the present invention has are:

The present invention adopts a mild, low energy consumption, non-toxic and safe hydrothermal method, takes activated carbon fiber as the base, is based on the mechanism of crystal heterogeneous nucleation and directional growth, combines the characteristics of hydrothermal reaction, starts with material selection, and adds soluble six Hydrate nickel nitrate, hexahydrate cobalt nitrate and sodium hypophosphite, and introduce crystallization directing agent N,N-dimethylacetamide, and comprehensively control various synthetic technical parameters to obtain dense and uniform M ₁₁ (HPO) loaded on the surface of activated carbon fibers. ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-like crystal array thin film. Guided by the principle of hydrothermal reaction, the invention utilizes the abundant and developed pore structure on the surface of the activated carbon fiber, which is beneficial to the formation of a nucleation center of crystal heterogeneous crystallization, and induces nickel ions, cobalt ions and hypophosphite ions to form supersaturation in the pore environment It is used as the substrate material for film growth; fully consider the factors affecting crystallization thermodynamics, set the appropriate reaction temperature and reaction time, and use the hydrothermal reaction method to generate pure M ₁₁ (HPO ₃ ) ₈ ( OH) ₆ (M=Ni+Co) rod-shaped crystal array film; the invention is also guided by the crystal growth mechanism to create a heterophase (Ni,Co) ₁₁ (HPO ₃ ) ₈ (OH) ₆ crystal that is beneficial to the surface of the activated carbon fiber The crystallization environment for crystallization and anisotropic growth, including using the porous structure on the surface of activated carbon fibers to provide a large number of nucleation centers for crystallization, and using the complexation of N,N-dimethylacetamide to adjust the crystallographic orientation and crystallization of hydroxyphosphite It can strengthen the anisotropic growth trend of hydroxyphosphite, control the concentration of reactive ions and reaction temperature to precisely adjust the crystal nucleation and growth rate, and obtain M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) thin film. The hydrothermal preparation method adopted in the present invention has a short synthetic route, mildness, low energy consumption and rapidity, and the obtained thin film layer has uniform crystal size and uniform chemical composition, and is a synthetic method suitable for mass production. This M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-like crystal array film has good bonding strength with the substrate activated carbon fiber, making M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) The application properties of +Co) crystals are extended by the structural form of the composites. In addition, the dense and uniform film form and the ordered rod-like array morphology are beneficial to the M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) crystal to exhibit more stable and uniform performance and convenience. application features. The M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-shaped crystal array film obtained by the present invention can be applied in the fields of novel electrode materials, photocatalysis and the like, and is also expected to be applied in the field of organic pollution decomposition.

Description of drawings

Figure 1 is the XRD pattern of the product obtained in Example 1.

Figure 2 is an electron microscope photograph of the product obtained in Example 1.

Figure 3 is an electron microscope photograph of the product obtained in Example 2.

Figure 4 is an electron microscope photograph of the product obtained in Example 3.

Detailed ways

In the M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-shaped crystal array film of the present invention, the diameter of the M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-shaped crystal is 100 nanometers -1 micron, densely arranged in an array to form a thin film.

Example 1:

Dissolve 0.2908 g of nickel nitrate hexahydrate, 0.2910 g of cobalt nitrate hexahydrate and 0.2120 g of sodium hypophosphite in 10 ml of deionized water and stir evenly, wherein the molar concentration ratio of nickel nitrate hexahydrate, cobalt nitrate hexahydrate and sodium hypophosphite is 1 :1:2, the total molar concentration of nickel ions and cobalt ions is 0.20 mol/L. 10 ml of N,N-dimethylacetamide was added to the mixed solution, and a homogeneous solution was obtained after magnetic stirring. Activated carbon fibers were obtained by heat-treating natural cotton fibers at 1000 °C for 1 h in a nitrogen atmosphere. Immerse the pre-cleaned activated carbon fibers in the above solution for 5 hours. The mixed solution, together with the activated carbon fibers, were reacted together at 160 °C for 10 h. After the reaction, the reaction kettle was naturally cooled to room temperature, and the activated carbon fibers were taken out, washed with absolute ethanol and deionized water for three times to remove impurities including surface adsorbed ions and attachments, and dried at 60 °C for 8 h. A dense and uniform M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-like crystal array thin film was obtained.

Fig. 1 is the XRD pattern of the product of Example 1. The characteristic diffraction peaks of the crystalline substance on the pattern correspond to the standard XRD pattern of Ni ₁₁ (HPO ₃ ) ₈ (OH) ₆ (JCPDS No 81-1065) and Co ₁₁ (HPO ₃ ) The ₈ (OH) ₆ standard XRD patterns (JCPDS No 81-1064) match, indicating that the crystal structure of the crystalline product is similar to that of Ni ₁₁ (HPO ₃ ) ₈ (OH) ₆ or Co ₁₁ (HPO ₃ ) ₈ (OH) ₆ , in which cobalt and nickel atoms occupy lattice positions in substitutional form in the crystal structure. Fig. 2 is an electron microscope photograph of the product of Example 1. M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-shaped crystal array film is formed on the surface of the activated carbon fiber. 800 nanometers, arranged in an array perpendicular to the fiber surface, and the array is dense.

Example 2:

Dissolve 0.2908 g of nickel nitrate hexahydrate, 0.2910 g of cobalt nitrate hexahydrate and 0.2120 g of sodium hypophosphite in 20 ml of deionized water and stir evenly, wherein the molar concentration ratio of nickel nitrate hexahydrate, cobalt nitrate hexahydrate and sodium hypophosphite is 1 :1:2, the total molar concentration of nickel ions and cobalt ions is 0.10 mol/liter. 20 ml of N,N-dimethylacetamide was added to the mixed solution, and a homogeneous solution was obtained after magnetic stirring. Activated carbon fibers were obtained by heat-treating natural cotton fibers at 1000 °C for 1 h in a nitrogen atmosphere. Immerse the pre-cleaned activated carbon fibers in the above solution for 5 hours. The mixed solution, together with the activated carbon fibers, were reacted together at 140 °C for 20 h. After the reaction, the reaction kettle was naturally cooled to room temperature, and the activated carbon fibers were taken out, washed with absolute ethanol and deionized water for three times to remove impurities including surface adsorbed ions and attachments, and dried at 60 °C for 8 h. A dense and uniform M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-like crystal array thin film was obtained.

Fig. 3 is the electron microscope photograph of the product of Example 2. M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-like crystal array film is formed on the surface of the activated carbon fiber, and the rods are uniform in size and have a diameter of 700 nm～ 1 micron, arranged in an array perpendicular to the fiber surface, and the array arrangement is dense.

Example 3:

Dissolve 0.5816 g of nickel nitrate hexahydrate, 0.5820 g of cobalt nitrate hexahydrate and 0.4140 g of sodium hypophosphite in 30 ml of deionized water and stir evenly, wherein the molar concentration ratio of nickel nitrate hexahydrate, cobalt nitrate hexahydrate and sodium hypophosphite is 1 :1:2, the total molar concentration of nickel ions and cobalt ions is 0.13 mol/L. 30 ml of N,N-dimethylacetamide was added to the mixed solution, and a homogeneous solution was obtained after magnetic stirring. Activated carbon fibers were obtained by heat-treating natural cotton fibers at 1000 °C for 1 h in a nitrogen atmosphere. Immerse the pre-cleaned activated carbon fibers in the above solution for 5 hours. The mixed solution, together with the activated carbon fibers, were reacted together at 150 °C for 12 h. After the reaction, the reaction kettle was naturally cooled to room temperature, and the activated carbon fibers were taken out, washed with absolute ethanol and deionized water for three times to remove impurities including surface adsorbed ions and attachments, and dried at 60 °C for 8 h. A dense and uniform M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-like crystal array thin film was obtained.

Fig. 4 is the electron microscope photograph of the product of Example 3. M ₁₁ (HPO ₃ ) ₈ (OH) ₆ (M=Ni+Co) rod-like crystal array film is formed on the surface of the activated carbon fiber, and the rods are uniform in size and have a diameter of 100 nanometers to 100 nanometers. 500 nanometers, arranged in an array perpendicular to the surface of the fiber, and the array is dense.

Claims (3)

1. A method for preparing a cobalt-nickel bimetal hydroxyl phosphite rodlike crystal array film is characterized in that the film is 100 nanometers to 1 micrometer (Ni, Co) in diameter ₁₁ (HPO ₃ ) ₈ (OH) ₆ Rod-shaped crystalThe film is formed by densely arranging the bodies in an array form; the preparation method of the film comprises the following steps:

1) dissolving nickel nitrate hexahydrate, cobalt nitrate hexahydrate and sodium hypophosphite into deionized water according to the molar concentration ratio of 1:1:2, wherein the total molar concentration of nickel ions and cobalt ions is 0.10-0.20 mol/L, and stirring to obtain a uniform solution;

2) adding N, N-dimethylacetamide into the solution, wherein the volume ratio of N, N-dimethylacetamide to deionized water is 1:1, and continuously stirring to obtain a uniform solution;

3) immersing the pre-cleaned activated carbon fiber in the solution obtained in the step 2) for 5 hours;

4) reacting the solution obtained in the step 3) and the activated carbon fiber for 10-20 hours at the temperature of 140-160 ℃;

5) naturally cooling the reaction kettle after the reaction in the step 4) to normal temperature, taking out the activated carbon fiber, repeatedly cleaning the activated carbon fiber for three times by absolute ethyl alcohol and deionized water, and drying the activated carbon fiber at the temperature of 60 ℃ for 8 hours to obtain a compact and uniform cobalt-nickel bimetallic hydroxyl phosphite rodlike crystal array film on the surface of the activated carbon fiber.

2. The method for preparing a cobalt-nickel bi-metal hydroxy phosphite rod-like crystal array film according to claim 1, wherein the method comprises the following steps: the activated carbon fiber is obtained by heat treatment of natural cotton fiber at 1000 ℃ for 1h in nitrogen atmosphere.

3. The film prepared by the method for preparing a cobalt-nickel bimetallic hydroxyphosphite rodlike crystal array film according to claim 1 or 2, wherein the method comprises the following steps: (Ni, Co) ₁₁ (HPO ₃ ) ₈ (OH) ₆ The diameter of the rod-shaped crystal is 100 nanometers to 1 micron, and the rod-shaped crystal is densely arranged in an array form to form a film.

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