Porous metal-based composite material as well as preparation method and application thereof

Abstract

The invention provides a porous metal-based composite material and a preparation method and application thereof, and belongs to the technical field of electrocatalysis, and the preparation method comprises the following steps: sequentially growing a reinforcement and an aluminum-cobaltosic oxide active nano-matrix on a foam skeleton carrier in situ; the composite material formed by in-situ growth by adopting a foam skeleton carrier as a matrix has a relatively high specific surface area, and active sites on the material are increased, so that an electrolyte can be in full contact with an active substance, and the composite material has relatively high catalytic property; metal-semiconductor contact is formed on a contact interface of the reinforcement and the foam skeleton carrier, and a first built-in electric field is formed in the whole structure; a Schottky junction is formed on a contact interface of the reinforcer and the aluminum-cobaltosic oxide active nano-matrix, a second built-in electric field is formed in the whole structure, electron transmission is accelerated through the double built-in electric fields, the oxygen production oxygen evolution reaction (OER) efficiency of the material can be improved, and the electro-catalysis requirement is met.

Description

Technical Field

[0001] The present application belongs to the field of electrocatalysis technology, and specifically relates to a porous metal-based composite material and a preparation method and application thereof. Background Art

[0002] Metal-ceramic matrix composites generally use active metal materials as the matrix and ceramic materials as the reinforcement phase. Although they combine the advantages of metal's light weight, good electrical and thermal conductivity, and ceramic's high hardness, high wear resistance, low thermal expansion coefficient and good chemical stability, they have broad application prospects in aerospace, electronic packaging, automobile manufacturing and other fields; however, metal-ceramic matrix composites are limited in use in the field of electrocatalysis and are difficult to meet actual needs. Summary of the invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art or related art.

[0004] To this end, a first aspect of the present invention provides a porous metal-based composite material.

[0005] A second aspect of the present invention provides a method for preparing a porous metal-based composite material.

[0006] The third aspect of the present invention provides an application of a porous metal-based composite material.

[0007] In view of this, according to a first aspect of an embodiment of the present application, a porous metal-based composite material is proposed, comprising: Foam skeleton carrier, reinforcement body, aluminum-cobalt tetroxide active nano-matrix, the reinforcement body is covered on the foam skeleton carrier, and the aluminum-cobalt tetroxide active nano-matrix is ​​grown on the reinforcement body; A metal-semiconductor contact junction is formed between the reinforcement and the foam skeleton carrier, forming a first built-in electric field; a Schottky junction is formed between the aluminum-cobalt tetroxide active nano-matrix and the reinforcement, forming a second built-in electric field.

[0008] In a feasible implementation manner, the reinforcement body is a wide bandgap material; The aluminum-cobalt oxide active nano-matrix is ​​a narrow bandgap material.

[0009] In a feasible implementation, the foam skeleton carrier is a foam metal skeleton; the reinforcement is a semiconductor material; The foam skeleton carrier is at least one of foam nickel, foam aluminum, foam copper and foam titanium; The reinforcement is at least one of silicon carbide, tungsten carbide, titanium carbide, tantalum carbide, boron carbide, zirconium carbide, molybdenum carbide and niobium carbide; The aluminum-cobalt tetroxide active nano-matrix comprises a cobalt tetroxide matrix and an active material, wherein the active material is doped in the cobalt tetroxide matrix; The active material is at least one of aluminum and an aluminum-based alloy.

[0010] According to a second aspect of an embodiment of the present application, a method for preparing a porous metal-based composite material is provided, which is used to prepare a porous metal-based composite material as in any of the above technical solutions, comprising: Pre-treating the foam skeleton carrier; Plasma treating the foam skeleton carrier to activate the foam skeleton carrier; The activated foam skeleton carrier is subjected to magnetron sputtering treatment to deposit a reinforcement on the surface of the activated foam skeleton carrier; The aluminum source and the cobalt source are configured into a mixed solution according to a certain ratio; The foam skeleton carrier after the reinforcement body is deposited is immersed in the mixed solution to carry out a hydrothermal reaction, and a porous metal matrix composite material is obtained after the reaction is completed.

[0011] In a feasible embodiment, pretreating the foam skeleton carrier comprises the steps of: Cut the foam skeleton carrier, put the foam skeleton carrier into a container filled with deionized water or an organic solvent, put the container into an ultrasonic cleaning machine, and clean it for 15 minutes to 30 minutes at a cleaning frequency of 40kHz to 80kHz; After cleaning, the foam skeleton carrier is taken out, rinsed with alcohol, blown dry with nitrogen, and then low-temperature dried.

[0012] In one possible embodiment, plasma treating the foam skeleton carrier to activate the foam skeleton carrier comprises the steps of: The foam skeleton carrier is placed in oxygen plasma and treated in an oxygen plasma atmosphere at a temperature of 300° C. to 700° C. to grow oxygen-containing compounds on the foam skeleton carrier.

[0013] In a feasible implementation, the activated foam skeleton carrier is subjected to magnetron sputtering treatment to deposit a reinforcement on the surface of the activated foam skeleton carrier, comprising the steps of: The foam skeleton carrier treated with plasma is placed in a magnetron sputtering device, the target material is installed, and the protective gas is introduced. Under the conditions of a pressure of 3Pa, a flow rate of 45sccm, a voltage of 18V, and a current of 8A, the magnetron sputtering treatment is carried out for 10min~40min, and a reinforcement with a thickness of 80nm~120nm is grown on the surface of the activated foam skeleton carrier.

[0014] In a feasible embodiment, 15 mL of deionized water and 15 mL of ethanol are measured, mixed and stirred evenly, 3 mmol of cobalt nitrate hexahydrate, 15 mmol of urea, and 3.9 mmol of ammonium fluoride are added in sequence, and stirred to dissolve to obtain solution A; 0.025 g of AlCl3 (4 wt%) was added to solution A and the mixture was stirred to dissolve to obtain a mixed solution B, which was used as a reaction solution for the hydrothermal reaction.

[0015] In a feasible implementation, the foam skeleton carrier after the reinforcement body is deposited is immersed in the mixed solution to perform a hydrothermal reaction, and the porous metal matrix composite material is obtained after the reaction is completed. The steps include: The mixed solution is transferred to a reaction kettle, and the foam skeleton carrier after the deposition reinforcement is placed in the reaction kettle. The mixture is kept at a temperature of 80°C to 150°C for 6h to 10h and then taken out. The porous metal matrix composite material is obtained by repeatedly washing with deionized water and alcohol and drying.

[0016] According to a third aspect of an embodiment of the present application, an application of a porous metal-based composite material is proposed, wherein the porous metal-based composite material as described in any of the above technical solutions is used as an electrode for an electrocatalytic reaction.

[0017] Compared with the prior art, the porous metal-based composite material and the preparation method and application thereof of the present invention have the following beneficial effects: The porous metal-based composite material provided in the embodiment of the present application includes a foam skeleton carrier, a reinforcement, and an aluminum-cobalt oxide active nano-matrix, and the reinforcement and the aluminum-cobalt oxide active nano-matrix are grown in situ on the foam skeleton carrier in sequence; the composite material formed by in situ growth using the foam skeleton carrier as a matrix has a high specific surface area, increases the active sites on the material, allows the electrolyte to fully contact the active substance, and has a stronger catalytic property; the contact interface between the reinforcement and the foam skeleton carrier forms a metal-semiconductor contact, forming a first built-in electric field in the overall structure; the contact interface between the reinforcement and the aluminum-cobalt oxide active nano-matrix forms a Schottky junction, forming a second built-in electric field in the overall structure, and the double built-in electric fields accelerate electron transmission, thereby improving the oxygen production and oxygen evolution reaction efficiency of the material and meeting the needs of electrocatalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present application. Also, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings: Figure 1A schematic flowchart of the steps of a method for preparing a porous metal-based composite material according to an embodiment of the present application; Figure 2 The scanning electron microscope images of the samples obtained in Example 1 and all the samples obtained in Comparative Example 1; Figure 3 X-ray diffraction patterns of the sample obtained in Example 1 and part of the sample obtained in Comparative Example 1; Figure 4 The Raman spectra of the samples obtained in Example 1 and some samples obtained in Comparative Example 1; FIG5(a) is a Co 2p orbital X-ray photoelectron spectrum of the aluminum-cobalt oxide / silicon carbide / nickel foam composite sample, the aluminum-cobalt oxide / nickel foam sample, the cobalt oxide / silicon carbide / nickel foam sample, and the cobalt oxide / nickel foam sample; FIG5( b ) is an O 1s orbital X-ray photoelectron spectrum of the aluminum-cobalt oxide / silicon carbide / nickel foam composite sample, the aluminum-cobalt oxide / nickel foam sample, the cobalt oxide / silicon carbide / nickel foam sample, and the cobalt oxide / nickel foam sample; FIG5(c) is the Ni 3p and Al 2p orbital X-ray photoelectron spectra of the aluminum-cobalt oxide / silicon carbide / nickel foam composite sample and the aluminum-cobalt oxide / nickel foam sample; FIG5( d ) is a Si 2p orbital X-ray photoelectron spectrum of the aluminum-cobalt oxide / silicon carbide / nickel foam composite material sample and the cobalt oxide / silicon carbide / nickel foam sample; FIG6( a ) is a polarization curve diagram of the aluminum-cobalt oxide / silicon carbide / nickel foam composite material sample, the aluminum-cobalt oxide / nickel foam sample, the cobalt oxide / silicon carbide / nickel foam sample, the cobalt oxide / nickel foam sample and the silicon carbide / nickel foam sample; FIG6(b) is a bar graph of the overpotential of the aluminum-cobalt oxide / silicon carbide / nickel foam composite sample, the aluminum-cobalt oxide / nickel foam sample, the cobalt oxide / silicon carbide / nickel foam sample, the cobalt oxide / nickel foam sample, and the silicon carbide / nickel foam sample at a current density of 10 mA / cm²; FIG6( c ) is a Tafel plot of the aluminum-cobalt oxide / silicon carbide / nickel foam composite material sample, the aluminum-cobalt oxide / nickel foam sample, the cobalt oxide / silicon carbide / nickel foam sample, the cobalt oxide / nickel foam sample, and the silicon carbide / nickel foam sample; FIG6( d ) is a linear fitting diagram of the capacitance current density and the scan rate of the aluminum-cobalt oxide / silicon carbide / nickel foam composite sample, the aluminum-cobalt oxide / nickel foam sample, the cobalt oxide / silicon carbide / nickel foam sample, the cobalt oxide / nickel foam sample and the silicon carbide / nickel foam sample; FIG7( a ) is a Mott-Schottky curve diagram of a silicon carbide / nickel foam sample; FIG7( b ) is a Mott-Schottky curve of the cobalt oxide / nickel foam sample; FIG7( c ) is a Mott-Schottky curve diagram of the aluminum-cobalt oxide / nickel foam sample; FIG7( d ) is a Mott-Schottky curve diagram of the aluminum-cobalt oxide / silicon carbide / nickel foam composite material sample. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present application are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present application and are not used to limit the present application.

[0020] According to the first aspect of the embodiment of the present application, a porous metal-based composite material is proposed, including: a foam skeleton carrier, a reinforcement, and an aluminum-cobalt oxide active nano-matrix, wherein the reinforcement is covered on the foam skeleton carrier, and the aluminum-cobalt oxide active nano-matrix is ​​grown on the reinforcement; a metal-semiconductor contact junction is formed between the reinforcement and the foam skeleton carrier, constituting a first built-in electric field; a Schottky junction is formed between the aluminum-cobalt oxide active nano-matrix and the reinforcement, constituting a second built-in electric field.

[0021] The porous metal-based composite material provided in the embodiment of the present application includes a foam skeleton carrier, a reinforcement, and an aluminum-cobalt oxide active nano-matrix. The reinforcement and the aluminum-cobalt oxide active nano-matrix are grown in situ on the foam skeleton carrier in sequence; the composite material formed by in situ growth using the foam skeleton carrier as a matrix has a high specific surface area, increases the active sites on the material, allows the electrolyte to fully contact the active substance, and has a stronger catalytic property; the contact interface between the reinforcement and the foam skeleton carrier forms a metal-semiconductor contact, forming a first built-in electric field in the overall structure; the contact interface between the reinforcement and the aluminum-cobalt oxide active nano-matrix forms a Schottky junction, forming a second built-in electric field in the overall structure, and the double built-in electric fields accelerate electron transfer, thereby improving the oxygen production and oxygen evolution reaction (OER) efficiency of the material and meeting the needs of electrocatalysis.

[0022] In a feasible implementation manner, the reinforcement body is a wide bandgap semiconductor material; and the aluminum-cobalt oxide active nano-matrix is ​​a narrow bandgap semiconductor material.

[0023] In this technical solution, a semiconductor material with a wide bandgap is magnetron sputtered on the surface of a foam skeleton carrier to form a reinforcement on the surface of the foam skeleton carrier. The semiconductor material with a wide bandgap provides chemical stability and thermal stability, so that the reinforcement can maintain structural integrity under harsh reaction conditions, provide stable support for the subsequently grown aluminum-cobalt tetroxide active nano-matrix, and prevent the aluminum-cobalt tetroxide active nano-matrix from structural damage or performance degradation during the reaction; then a layer of narrow bandgap semiconductor material is grown on the surface of the semiconductor material with a wide bandgap to grow an aluminum-cobalt tetroxide active nano-matrix on the surface of the reinforcement. The aluminum-cobalt tetroxide active nano-matrix grows on the wide bandgap material, forming a double built-in electric field in the material structure, namely a metal-semiconductor contact junction and a Schottky junction, thereby accelerating electron transmission through the double built-in electric field to improve the oxygen production and oxygen evolution reaction efficiency of the material, so that the composite material can be applied in the field of electrocatalysis.

[0024] In a feasible embodiment, the foam skeleton carrier is a foam metal skeleton; the reinforcement is a semiconductor material; the foam skeleton carrier is at least one of foam nickel, foam aluminum, foam copper and foam titanium; the reinforcement is made of carbide material, and the reinforcement is at least one of silicon carbide, tungsten carbide, titanium carbide, tantalum carbide, boron carbide, zirconium carbide, molybdenum carbide and niobium carbide; the aluminum-cobalt oxide active nanomatrix includes a cobalt oxide matrix and an active material, and the active material is doped in the cobalt oxide matrix; the active material is at least one of aluminum and an aluminum-based alloy.

[0025] In this technical solution, the reinforcement is made of semiconductor material, and the foam skeleton carrier is made of foam metal skeleton, so that the contact interface between the reinforcement and the foam skeleton carrier forms metal-semiconductor contact, forming a first built-in electric field; the foam metal skeleton has a good three-dimensional porous network structure, which provides stable physical support for the entire material system, so that the subsequently grown reinforcement aluminum-cobalt oxide active nano-matrix can be stably attached, maintain the overall shape of the material, and avoid the material from easily collapsing or deforming during the reaction; at the same time, the porous foam metal skeleton structure increases the specific surface area of ​​the material, so that more active sites can be exposed to the reaction environment, which is beneficial to the full contact between the reactants and the aluminum-cobalt oxide active nano-matrix, thereby improving the reaction rate and catalytic activity, and enhancing the catalytic performance of the composite material. Doping aluminum or aluminum-based alloys into the cobalt tetroxide matrix can change the electron cloud distribution and energy band structure of the cobalt tetroxide matrix, reduce resistance, and increase carrier mobility, thereby improving the performance of the material in processes such as electrocatalysis, promoting the electron transfer process, and accelerating the reaction; the doped aluminum or aluminum-based alloy can participate in the reaction as a new active site, interact with the cobalt tetroxide matrix, increase the number of sites that can adsorb and activate reactants, and further improve the catalytic activity of the material and the selectivity of the target reaction; at the same time, the doping of aluminum or aluminum-based alloys can also enhance the structural stability of the cobalt tetroxide matrix. During the reaction, aluminum or aluminum-based alloys can form Al-O-Co interface chemical bonds with the cobalt tetroxide matrix, and regulate oxygen vacancies, so that aluminum-cobalt tetroxide has both electron transfer and solid solution effects, which is beneficial to improving the mechanical, catalytic and electrochemical properties of the composite material, inhibiting the structural collapse and phase change of the cobalt tetroxide matrix, and enabling the cobalt tetroxide active nano-matrix to maintain good performance during a long reaction process.

[0026] As a preferred solution, the foam skeleton carrier uses nickel foam (Ni-foam), the reinforcement uses magnetron sputtered silicon carbide (SiC), the silicon carbide / nickel foam forms a metal-semiconductor contact, the aluminum-cobalt tetroxide / silicon carbide forms a Schottky junction, and two built-in electric fields are constructed in the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material structure to accelerate electron transmission, so that the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material can be used in the field of electrocatalysis. Specifically, the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material nanowires form a lily shape, the active sites are significantly increased, and a large number of active sites allow the electrolyte to fully contact the active substance, which is conducive to improving the efficiency of the catalytic reaction.

[0027] like Figure 1 As shown, according to the second aspect of the present application, a method for preparing a porous metal-based composite material is proposed, which is used to prepare a porous metal-based composite material as in any one of the above technical solutions, and the preparation method comprises: Step 100: pretreating the foam skeleton carrier; removing impurities on the surface of the foam skeleton carrier, improving the bonding force between the foam skeleton carrier and the reinforcement, and thereby ensuring the quality and performance of the reinforcement material subsequently grown on the foam skeleton carrier; Step 200: Plasma treatment of the foam skeleton carrier to activate the foam skeleton carrier; placing the foam skeleton carrier in a plasma atmosphere for treatment to activate the foam skeleton carrier, provide better substrate conditions for the subsequent growth of the reinforcement, and enhance the bonding force between the foam skeleton carrier and the reinforcement, so as to better grow the reinforcement on the surface of the foam skeleton carrier; Step 300: performing magnetron sputtering treatment on the activated foam skeleton carrier to deposit reinforcement on the surface of the activated foam skeleton carrier; placing the foam skeleton carrier treated with plasma into a magnetron sputtering device to perform magnetron sputtering treatment to grow reinforcement on the surface of the foam skeleton carrier to form a composite material combining the reinforcement and the foam skeleton carrier; Step 400: preparing an aluminum source and a cobalt source into a mixed solution in a certain ratio; accurately controlling the concentrations of aluminum ions and cobalt ions in the mixed solution to accurately control the growth rate and quality of the active material in the subsequent reaction, thereby achieving regulation of the composition and performance of the final product; Step 500: Immersing the foam skeleton carrier after depositing the reinforcement into the mixed solution for hydrothermal reaction, and obtaining a porous metal-based composite material after the reaction is completed; through the hydrothermal reaction, the aluminum-cobalt tetroxide active nano-matrix with catalytic activity is compounded with the reinforcement with supporting and protective functions and the foam skeleton carrier as a substrate to form a porous metal-based composite material.

[0028] By the preparation method of the porous metal-based composite material provided in the embodiment of the present application, a foam skeleton carrier is used as a matrix, and in-situ growth is performed on a plasma-treated foam skeleton carrier by adopting magnetron sputtering and hydrothermal reaction methods to form a porous metal-based composite material. Not only is a dual built-in electric field formed in the composite material structure, which accelerates the transmission of electrons and can improve the efficiency of oxygen evolution reaction (OER) in oxygen production; moreover, by changing the concentrations of aluminum source and cobalt source in the mixed solution, the interface and electronic state density between the composite materials can be controlled, thereby controlling the morphology of the porous metal-based composite material, so that the porous metal-based composite material can meet the catalytic needs in the field of electrocatalysis.

[0029] Existing methods for preparing metal-ceramic matrix composite materials include powder metallurgy, in-situ generation and mechanical stirring. Take aluminum-cobalt oxide / silicon carbide composite materials as an example: Powder metallurgy method: First, aluminum powder, cobalt oxide powder and silicon carbide powder are uniformly mixed in a ball mill according to a certain proportion. Dry mixing or wet mixing can be used. The mixed powder is cold pressed into a blank, vacuum degassing, hot pressing sintering, and subsequent extrusion, rolling, heat treatment, etc. to obtain a composite material. The size and content of the reinforcement can be controlled to ensure its uniform distribution in the matrix, but the process is cumbersome and requires specific working conditions. Improper sintering temperature will lead to segregation.

[0030] In-situ generation method: Select appropriate reactants, raise the temperature under specific conditions to make the elements in the raw materials undergo physical and chemical reactions, and generate uniformly distributed cobalt tetroxide and silicon carbide reinforcements inside the material. The advantages are uniform distribution of reinforcements, clean interface, and simple process, but there are requirements for raw materials, reaction by-products are difficult to control, and there are interface problems.

[0031] Mechanical stirring method: During the stirring process, cobalt oxide and silicon carbide particles are added to the liquid aluminum, and a high-speed rotating stirring device is used to evenly mix them, and then poured into the mold. The operation is simple and the cost is low. There are two methods: liquid stirring and semi-solid stirring. Semi-solid stirring can make the reinforcement particles more evenly distributed.

[0032] The above three methods for preparing aluminum-cobalt tetroxide / silicon carbide composite materials are multi-component composite materials with aluminum as the matrix and cobalt tetroxide and silicon carbide as the reinforcing phase. Although it combines the advantages of light weight, good electrical and thermal conductivity of aluminum, the unique electrical and magnetic properties of cobalt tetroxide, and the high hardness, high wear resistance, low thermal expansion coefficient and good chemical stability of silicon carbide; however, the interface and electronic state density between the prepared aluminum-cobalt tetroxide / silicon carbide composite materials cannot be regulated, and the morphology is uncontrollable, and in-situ growth cannot be achieved. The shape of the electrode can be changed at will, and it cannot be used in the field of electrocatalysis. The present application adopts a method of magnetron sputtering combined with hydrothermal reaction to in-situ grow aluminum-cobalt tetroxide / silicon carbide on a plasma-treated foam skeleton carrier, and then by changing the concentration of aluminum source and cobalt source in the mixed solution, the interface and electronic state density between the composite materials can be controlled, and then the morphology of the porous metal-based composite material can be controlled, so that the porous metal-based composite material can meet the catalytic needs in the field of electrocatalysis.

[0033] In a feasible embodiment, pretreating the foam skeleton carrier includes the steps of: cutting the foam skeleton carrier, placing the foam skeleton carrier into a container filled with deionized water or an organic solvent, placing the container into an ultrasonic cleaning machine, and cleaning at a cleaning frequency of 40kHz to 80kHz for 15min to 30min; after cleaning, taking out the foam skeleton carrier, rinsing it with alcohol, blowing it dry with nitrogen, and then low-temperature drying it.

[0034] In this technical solution, ultrasonic cleaning with deionized water or organic solvent can effectively remove impurities on the foam skeleton carrier to ensure the quality and performance of the material of the reinforcement body subsequently grown on the foam skeleton carrier; by timely drying the foam skeleton carrier, the moisture on the foam skeleton carrier is prevented from absorbing impurities in the air, and corrosion of the foam skeleton carrier is avoided; the dried foam skeleton carrier can better match other materials or process conditions when subjected to plasma atmosphere treatment, which is beneficial to improving the uniformity and stability of the effects of plasma treatment and magnetron sputtering treatment.

[0035] Furthermore, the foam skeleton carrier can be cleaned with weak acid, weak base or neutral organic solvent such as ethanol and acetone.

[0036] In a feasible embodiment, the foam skeleton carrier is plasma treated to activate the foam skeleton carrier, including the steps of placing the foam skeleton carrier in oxygen plasma, treating the foam skeleton carrier in an oxygen plasma atmosphere at a temperature of 300°C to 700°C, and growing oxygen groups on the foam skeleton carrier.

[0037] In this technical solution, the foam skeleton carrier is placed in an oxygen plasma atmosphere at 300°C to 700°C for treatment to grow oxygen groups on the surface of the foam skeleton carrier, so that the reinforcement can form a strong coupling with the surface of the foam skeleton carrier, thereby improving the adhesion of the reinforcement growth.

[0038] In some examples, when the foam skeleton carrier is nickel foam and the reinforcement is silicon carbide, the nickel foam is treated in an oxygen plasma atmosphere so that oxygen groups grow on the nickel foam to form Ni-O bonds and Ni-OH bonds, so that silicon carbide can form a strong coupling with the surface of the nickel foam, thereby improving the adhesion of silicon carbide and ensuring the structural stability and reliability of the combination of silicon carbide and nickel foam.

[0039] In a feasible implementation manner, the activated foam skeleton carrier is subjected to magnetron sputtering treatment, and a reinforcement body is deposited on the surface of the activated foam skeleton carrier, comprising the steps of placing the foam skeleton carrier treated with plasma into a magnetron sputtering device, installing a target material, introducing a protective gas, and performing magnetron sputtering treatment for 10 min to 40 min under the conditions of a pressure of 3 Pa, a flow rate of 45 sccm, a voltage of 18 V, and a current of 8 A, so as to grow a reinforcement body with a thickness of 80 nm to 120 nm on the surface of the activated foam skeleton carrier.

[0040] In this technical solution, the conditions of the magnetron sputtering treatment are precisely controlled to grow a reinforcement of a preset thickness on the surface of the foam skeleton carrier to obtain a composite material of the reinforcement and the foam skeleton carrier, and to form a metal-semiconductor contact junction between the foam skeleton carrier and the reinforcement to constitute a first built-in electric field.

[0041] As a preferred solution, a high-purity silicon carbide ceramic target is installed, argon gas is introduced as a protective gas, and the activated nickel foam is magnetron sputtered for 10 minutes, so that silicon carbide with a thickness of about 100 nm can be grown on the nickel foam to obtain a silicon carbide / nickel foam composite material.

[0042] In a feasible embodiment, an aluminum source and a cobalt source are configured into a mixed solution in a certain proportion, comprising the steps of: measuring 15 mL of deionized water and 15 mL of ethanol, mixing and stirring evenly, adding 3 mmol (millimoles) of cobalt nitrate hexahydrate, 15 mmol of urea, and 3.9 mmol of ammonium fluoride in sequence, stirring and dissolving to obtain solution A; adding 0.025 g of AlCl3 (the mass of aluminum chloride accounts for 4% of the total mass of the solution) to solution A, stirring and dissolving to obtain a mixed solution B, and the mixed solution B is used as a reaction solution for a hydrothermal reaction.

[0043] In this technical solution, the concentrations of aluminum ions and cobalt ions are precisely controlled so that when the aluminum-cobalt tetroxide active nanomatrix is ​​subsequently grown, the interface and electronic state density between the aluminum-cobalt tetroxide active nanomatrix and the reinforcement are controlled, thereby making the morphology of the subsequent growth of the aluminum-cobalt tetroxide active nanomatrix controllable, so as to control the in-situ growth of an aluminum-cobalt tetroxide active nanomatrix of a specific shape on the foam skeleton carrier and the reinforcement.

[0044] In this technical solution, the morphology control of the aluminum-cobalt oxide / silicon carbide / nickel foam electrode can be achieved by changing the concentration of the reaction material solution. The aluminum-cobalt oxide / silicon carbide / nickel foam composite material prepared by using the mixed solution of this ratio has a regular morphology, and the nanowires form a lily shape, which makes the aluminum-cobalt oxide / silicon carbide / nickel foam composite material have a higher specific surface area, increases the active sites of the composite material, and enables the electrolyte to fully contact with the active substance, thereby improving the catalytic efficiency.

[0045] It should be noted that in the field of electrocatalysis, the electrode morphology and interface electronic state density directly determine the electrode catalytic activity, stability and mass transfer efficiency. During in-situ growth, by dynamically regulating the growth process of aluminum-cobalt oxide materials, the morphology of the composite material can be controlled and the interface electronic structure can be optimized, thereby changing the shape of the electrode, breaking through the limitation that traditional composite materials cannot be used in the field of electrocatalysis due to the difficulty in controlling the morphology.

[0046] In a feasible embodiment, the foam skeleton carrier after the reinforcement body is deposited is immersed in the mixed solution, a hydrothermal reaction is carried out, and a porous metal-based composite material is obtained after the reaction is completed. The steps include: transferring the mixed solution B to a reactor, placing the foam skeleton carrier after the reinforcement body is deposited, keeping it warm for 6h~10h at a temperature of 80°C~150°C, and then taking it out; repeatedly washing it with deionized water and alcohol, and obtaining the porous metal-based composite material after drying.

[0047] In this technical scheme, the mixed solution is transferred to a reactor, and a foam skeleton carrier treated with plasma is placed in it for a hydrothermal reaction to in-situ grow an aluminum-cobalt oxide active nanomatrix on the reinforcement; then, the composite material is taken out after being kept warm for 6h~10h at a temperature of 80℃~150℃, and a porous metal-based composite material is obtained after repeated washing and drying.

[0048] As a preferred solution, the mixed solution is transferred to a reaction kettle, and the nickel foam treated with plasma is placed in it for a hydrothermal reaction to in-situ grow an aluminum-cobalt tetroxide active nano-matrix on the silicon carbide reinforcement; then, the composite material is taken out after being kept warm for 8 hours at a temperature of 120°C, and is repeatedly washed and dried to obtain an aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material.

[0049] It can be understood that the method for preparing the porous metal-based composite material provided in the embodiment of the present application is applied to the porous metal-based composite material such as any of the above-mentioned technical solutions. Therefore, the method for preparing the porous metal-based composite material has all the beneficial effects of the porous metal-based composite material of the above-mentioned technical solutions, which will not be elaborated here.

[0050] According to the third aspect of the present application, an application of a porous metal-based composite material is proposed, wherein the porous metal-based composite material as described in any one of the above technical solutions is used as an electrode for an electrocatalytic reaction.

[0051] It can be understood that the application of the porous metal-based composite material provided in the embodiment of the present application includes the porous metal-based composite material such as any of the above-mentioned technical solutions. Therefore, the preparation method of the porous metal-based composite material has all the beneficial effects of the porous metal-based composite material of the above-mentioned technical solutions, which will not be elaborated here.

[0052] Example 1 The specific preparation method of the aluminum-cobalt oxide / silicon carbide / nickel foam composite material is as follows: Step 100': Cut the nickel foam into a rectangle of 1.2 cm × 1.5 cm, put the nickel foam into an appropriate amount of deionized water, and then put the container into an ultrasonic cleaning machine, and clean it at a cleaning frequency of 60 kHz for 30 minutes; after cleaning, take out the nickel foam, rinse it with alcohol, blow it dry with nitrogen, and then dry the nickel foam in a vacuum drying oven at low temperature; Step 200': placing the nickel foam in a 300°C oxygen plasma atmosphere to grow nickel oxide on the surface of the nickel foam; Step 300': placing the nickel foam treated with plasma into a magnetron sputtering device, installing a silicon carbide target, introducing Ar, and performing magnetron sputtering for 10 minutes at a pressure of 3 Pa, a flow rate of 45 sccm, a voltage of 18 V, and a current of 8 A to grow silicon carbide with a thickness of 100 nm on the surface of the nickel foam, thereby obtaining a silicon carbide / nickel foam composite material; Step 400': 15 mL of deionized water and 15 mL of ethanol were measured and mixed and stirred evenly, and 3 mmol of cobalt nitrate hexahydrate (0.873 g), 15 mmol of urea, and 3.9 mmol of ammonium fluoride were added in sequence, and stirred to dissolve to obtain solution A; 0.025 g of AlCl3 (4 wt%) was added to solution A, and stirred to dissolve to obtain a mixed solution B; Step 500': transfer the mixed solution B to a reaction kettle, put in silicon carbide / nickel foam (nickel foam after plasma treatment), keep warm at 120°C for 8 hours, take out, and repeatedly wash with deionized water and alcohol, and obtain an aluminum-cobalt oxide / silicon carbide / nickel foam composite material sample after drying.

[0053] Comparative Example 1 Samples of five materials, namely nickel foam, silicon carbide / nickel foam, cobalt oxide / nickel foam, aluminum-cobalt oxide / nickel foam, and cobalt oxide / silicon carbide / nickel foam, were prepared and compared with the aluminum-cobalt oxide / silicon carbide / nickel foam composite material sample prepared in Example 1.

[0054] The specific preparation method of nickel foam is as follows: cut the nickel foam into a rectangle of 1.2 cm × 1.5 cm, put the nickel foam into an appropriate amount of deionized water, and then put the container into an ultrasonic cleaning machine, and clean it at a cleaning frequency of 60 kHz for 30 minutes; after cleaning, take out the nickel foam, rinse it with alcohol, blow it dry with nitrogen, and then dry the nickel foam in a vacuum drying oven at low temperature; put the nickel foam into a 300°C oxygen plasma atmosphere for treatment, grow nickel oxide on the surface of the nickel foam, and obtain a nickel foam sample.

[0055] The preparation method of silicon carbide / nickel foam is as follows: cutting the nickel foam into a rectangle of 1.2 cm×1.5 cm, putting the nickel foam into an appropriate amount of deionized water, and then putting the container into an ultrasonic cleaning machine, and cleaning it at a cleaning frequency of 60 kHz for 30 minutes; after cleaning, taking out the nickel foam, rinsing it with alcohol, and blowing it dry with nitrogen, and then drying the nickel foam at low temperature in a vacuum drying oven; placing the nickel foam in a 300°C oxygen plasma atmosphere for treatment, growing nickel oxide on the surface of the nickel foam, and obtaining nickel foam; placing the nickel foam treated with plasma in a magnetron sputtering device, installing a silicon carbide target, introducing Ar, and performing magnetron sputtering for 10 minutes under the parameter settings of pressure 3Pa, flow rate 45sccm, voltage 18V, and current 8A, growing silicon carbide with a thickness of 100nm on the surface of the nickel foam, and obtaining a silicon carbide / nickel foam composite material sample.

[0056] The specific preparation method of cobalt oxide / silicon carbide / nickel foam is as follows: on the basis of obtaining the silicon carbide / nickel foam composite material, 15 mL of deionized water and 15 mL of ethanol are measured, and mixed and stirred evenly, 3 mmol of cobalt nitrate hexahydrate (0.873 g), 15 mmol of urea, and 3.9 mmol of ammonium fluoride are added in sequence, and stirred to dissolve to obtain solution A; solution A is transferred to a reaction kettle, and silicon carbide / nickel foam is put in, and the solution is taken out after being kept warm at 120°C for 8 hours, and repeatedly washed with deionized water and alcohol, and dried to obtain a cobalt oxide / silicon carbide / nickel foam composite material sample.

[0057] The specific preparation method of cobalt tetroxide / nickel foam is as follows: on the basis of the nickel foam obtained after plasma treatment, 15 mL of deionized water and 15 mL of ethanol are measured, and the mixture is stirred evenly, and 3 mmol of cobalt nitrate hexahydrate (0.873 g), 15 mmol of urea, and 3.9 mmol of ammonium fluoride are added in sequence, and the mixture is stirred to dissolve to obtain solution A; solution A is transferred to a reaction kettle, and the nickel foam after plasma treatment is put in, and the solution is taken out after being kept warm at 120°C for 8 hours, and is repeatedly washed with deionized water and alcohol, and dried to obtain a cobalt tetroxide / nickel foam composite material sample.

[0058] The specific preparation method of aluminum-cobalt tetroxide / nickel foam is as follows: on the basis of obtaining the nickel foam after plasma treatment, measure 15mL of deionized water and 15mL of ethanol, mix and stir evenly, add 3mmol of cobalt nitrate hexahydrate (0.873g), 15mmol of urea, and 3.9mmol of ammonium fluoride in sequence, stir and dissolve to obtain solution A; then add 0.025gAlCl3 (4wt%) to solution A, stir and dissolve to obtain a mixed solution B; transfer the mixed solution B to a reactor, put in the cut plasma-treated nickel foam, keep it at 120°C for 8 hours, take it out, and repeatedly wash it with deionized water and alcohol, and obtain an aluminum-cobalt tetroxide / nickel foam composite material sample after drying.

[0059] The nickel foam sample, silicon carbide / nickel foam sample, cobalt oxide / silicon carbide / nickel foam sample, aluminum-cobalt oxide / nickel foam sample, cobalt oxide / nickel foam sample and aluminum-cobalt oxide / silicon carbide / nickel foam composite sample prepared in Example 1 were characterized, analyzed, tested for catalytic performance and derived models: 1. Scanning electron microscopy (SEM) characterization The nickel foam sample, silicon carbide / nickel foam sample, cobalt tetroxide / silicon carbide / nickel foam sample, aluminum-cobalt tetroxide / nickel foam sample, cobalt tetroxide / nickel foam sample obtained in Comparative Example 1 and the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material sample prepared in Example 1 were characterized by scanning electron microscopy. Figure 2 The following are scanning electron microscope photos of six sample materials: nickel foam, silicon carbide / nickel foam, cobalt oxide / nickel foam, aluminum-cobalt oxide / nickel foam, cobalt oxide / silicon carbide / nickel foam, and aluminum-cobalt oxide / silicon carbide / nickel foam. Figure 2 In the figure, (a1) and (a2) are scanning electron microscopy characterizations of nickel foam samples, (b1) and (b2) are scanning electron microscopy characterizations of silicon carbide / nickel foam composite samples, (c1) and (c2) are scanning electron microscopy characterizations of cobalt tetroxide / nickel foam composite samples, (d1) and (d2) are scanning electron microscopy characterizations of aluminum-cobalt tetroxide / nickel foam composite samples, (e1) and (e2) are scanning electron microscopy characterizations of cobalt tetroxide / silicon carbide / nickel foam composite samples, and (f1) and (f2) are scanning electron microscopy characterizations of aluminum-cobalt tetroxide / silicon carbide / nickel foam composite samples.

[0060] From the scanning electron microscopy characterization of the six samples, it can be seen that the aluminum-cobalt oxide / silicon carbide / nickel foam composite material has the largest specific surface area and a natural shape. By controlling the interface and electronic state density between the aluminum-cobalt oxide / silicon carbide / nickel foam composite materials, the morphology of the aluminum-cobalt oxide / silicon carbide / nickel foam composite material is regular, and the aluminum-cobalt oxide / silicon carbide / nickel foam composite material nanowires form a lily shape, and the active sites are significantly increased; in the electrocatalytic reaction, the shape of the aluminum-cobalt oxide / silicon carbide / nickel foam composite electrode can be changed at will by controlling the in-situ growth, and a large number of active sites allow the electrolyte to fully contact the active substance, which is beneficial to improving the efficiency of the catalytic reaction.

[0061] 2. X-ray diffraction (XRD) characterization The silicon carbide / nickel foam composite material sample, the cobalt tetroxide / silicon carbide / nickel foam composite material sample, the aluminum-cobalt tetroxide / nickel foam composite material sample, the cobalt tetroxide / nickel foam sample obtained in Comparative Example 1 and the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material sample prepared in Example 1 were characterized by X-ray diffraction. Figure 3 It is an X-ray diffraction pattern. The five diffraction lines correspond to silicon carbide / nickel foam, cobalt oxide / nickel foam, cobalt oxide / silicon carbide / nickel foam, aluminum-cobalt oxide / nickel foam and aluminum-cobalt oxide / silicon carbide / nickel foam. It should be noted that silicon carbide / nickel foam, cobalt oxide / nickel foam, cobalt oxide / silicon carbide / nickel foam, aluminum-cobalt oxide / nickel foam and aluminum-cobalt oxide / silicon carbide / nickel foam samples all contain nickel foam (Ni-foam). For simplification, Figure 3 When marking, the nickel foam is omitted, that is, silicon carbide / nickel foam is Figure 3 In the figure, SiC, Cobalt Tetroxide / Nickel Foam Figure 3 In the marked as Co3O4, cobalt tetraoxide / silicon carbide / nickel foam Figure 3 In the figure, it is marked as Co3O4 / SiC, aluminum-cobalt tetroxide / nickel foam. Figure 3 In the marked as Al-Co3O4, aluminum-cobalt tetraoxide / silicon carbide / nickel foam Figure 3 Marked as Al-Co3O4 / SiC.

[0062] like Figure 3 As shown, the above five samples have three peaks (marked by inverted triangles) at 2θ=44.8°, 52.3° and 76.1°, corresponding to the (111), (200) and (220) planes of cubic phase metallic nickel [JCPDS70-1849], respectively.

[0063] For the SiC diffraction line, there are four peaks (diamond marks) at 2θ = 34.2°, 35.7°, 38.2° and 41.5°, belonging to the (101), (102), (103) and (104) planes of SiC [JCPDS29-1131].

[0064] For the diffraction lines of cobalt tetroxide, there are seven peaks (marked with solid circles) at 2θ = 18.9°, 31.3°, 36.8°, 38.5°, 55.7°, 59.4° and 65.2°, corresponding to the (111), (220), (311), (222), (422), (511) and (440) planes of cobalt tetroxide [JCPDS74-2120], respectively.

[0065] It can be seen from the X-ray diffraction characterization that the doping of aluminum does not change the crystal structure of cobalt oxide, and thus does not affect the unique electrical and magnetic properties of cobalt oxide; at the same time, it can be seen from the leftward shift of the diffraction peak that aluminum-cobalt oxide meets the characteristics of doping, and effective doping of aluminum in cobalt oxide is achieved through hydrothermal reaction.

[0066] 3. Raman spectroscopy characterization The cobalt oxide / silicon carbide / nickel foam sample, aluminum-cobalt oxide / nickel foam sample, cobalt oxide / nickel foam sample obtained in Comparative Example 1 and the aluminum-cobalt oxide / silicon carbide / nickel foam composite material sample prepared in Example 1 were characterized by Raman spectroscopy. Figure 4 It is a Raman spectrum diagram. The four Raman lines correspond to the cobalt oxide / silicon carbide / nickel foam sample, cobalt oxide / nickel foam sample, aluminum-cobalt oxide / nickel foam sample, and aluminum-cobalt oxide / silicon carbide / nickel foam sample from bottom to top. It should be noted that the cobalt oxide / silicon carbide / nickel foam sample, cobalt oxide / nickel foam sample, aluminum-cobalt oxide / nickel foam sample, and aluminum-cobalt oxide / silicon carbide / nickel foam sample all contain nickel foam components. For simplification, Figure 4 In the marking, the nickel foam is omitted, that is, cobalt tetroxide / silicon carbide / nickel foam is Figure 4 In the figure, it is marked as Co3O4 / SiC, Co3O4 / Ni foam. Figure 4 In the figure, it is marked as Co3O4, aluminum-cobalt tetraoxide / nickel foam Figure 4 In the marked as Al-Co3O4, aluminum-cobalt tetraoxide / silicon carbide / nickel foam Figure 4 Marked as Al-Co3O4 / SiC.

[0067] like Figure 4 As shown in Figure 2, the characteristic peaks of the Raman spectra of the above four samples are consistent with the typical spinel cobalt tetroxide structure; however, since silicon carbide is too thin, it is not easy to detect. 2g (193cm -1 ) and A 1g (676cm -1 ) represent the stretching vibration of the tetrahedral site (CoO4) and the octahedral site (CoO6) in CoO4. In addition, with the addition of aluminum, F 2g and A 1g The peak of is obviously red-shifted, which is related to the change of the long-range order of the lattice. It can be determined that aluminum doping causes more metal vacancies to be formed in aluminum-cobalt tetroxide.

[0068] 4. X-ray Electron Spectroscopy (XPS) Characterization In order to further illustrate the surface chemical structure of each sample, X-ray electron spectroscopy analysis was performed on the cobalt oxide / nickel foam sample, aluminum-cobalt oxide / nickel foam sample, cobalt oxide / silicon carbide / nickel foam sample obtained in Comparative Example 1 and the aluminum-cobalt oxide / silicon carbide / nickel foam composite material sample prepared in Example 1, as shown in Figure 5 (a) Co 2p orbital, Figure 5 (b) O 1s orbital, Figure 5 (c) Ni 3p and Al 2p orbitals, and Figure 5 (d) Si 2p orbital. It should be noted that the cobalt tetroxide / nickel foam sample, aluminum-cobalt tetroxide / nickel foam sample, cobalt tetroxide / silicon carbide / nickel foam sample and aluminum-cobalt tetroxide / silicon carbide / nickel foam sample all contain nickel foam components. In order to simplify the annotation of Figure 5(a), Figure 5(b), Figure 5(c) and Figure 5(d), nickel foam is omitted in the annotation, that is, cobalt tetroxide / silicon carbide / nickel foam is annotated as Co3O4 / SiC in Figure 5(a), Figure 5(b) and Figure 5(d), cobalt tetroxide / nickel foam is annotated as Co3O4 in Figure 5(a) and Figure 5(b), aluminum-cobalt tetroxide / nickel foam is annotated as Al-Co3O4 in Figure 5(a), Figure 5(b) and Figure 5(c), and aluminum-cobalt tetroxide / silicon carbide / nickel foam is annotated as Al-Co3O4 in Figure 5(a), Figure 5(b), Figure 5(c) and Figure 5(d). The Co2p spectra of the above four samples show mixed valence Co 2+ and Co 3+ Based on the relative area of ​​the fitted peaks, the Co in samples CoO / Ni foam, Al-CoO / Ni foam, CoO / SiC / Ni foam and Al-CoO 3+ / Co 2+ The ratios of Al and Co are 0.63, 0.69, 0.79 and 0.98 respectively. It can be seen that Al doping tends to replace Co 2+ , which reduces the concentration of electron states around Co atoms. 2+ The composition shows that the cation vacancies are mainly located around the tetrahedral sites. At the same time, the composite of silicon carbide also makes Co 3+ / Co 2+ The ratio increases. This is consistent with the Raman spectroscopy results. The O1s spectrum shows that the peak positions at 529.5, 531.1 and 532.2 eV are respectively attributed to O 2- (lattice oxygen), OH - (oxygen vacancies) and H2O (surface adsorbed oxygen).

[0069] It is not difficult to find that the introduction of silicon carbide greatly reduces the ratio of lattice oxygen / oxygen vacancies from the original 2.0 to 0.8. For Ni3p and Al2p spectra, after the introduction of silicon carbide, the peaks at 67.3eV (Ni-O) and 72.9eV (Al-O) are obviously moved to 68.2eV (Ni-O) and 73.9eV (Al-O) peaks, indicating that the electronic state density has increased significantly. For Si2p spectrum, there are three obvious peaks, located at 101.7eV (Si-CO), 103.0eV (Si-O), and 104.6eV (SiO2), respectively. The introduction of Al doping does not have much effect on it, that is, it does not have a significant impact on the high hardness, high wear resistance, low thermal expansion coefficient and good chemical stability of silicon carbide.

[0070] 5. Catalytic test The catalytic test adopts the linear sweep voltammetry (LSV), Tafel polarization (Tafel), cyclic voltammetry (CV) and other methods in the electrochemical measurement method, and the silicon carbide / nickel foam sample, cobalt tetroxide / silicon carbide / nickel foam sample, aluminum-cobalt tetroxide / nickel foam sample, cobalt tetroxide / nickel foam sample and aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material sample prepared in Example 1 are tested for oxygen reduction and oxygen evolution. To illustrate the oxygen reduction performance of the sample, a series of electrochemical tests were performed in a three-electrode system of 1M KOH electrolyte (alkaline electrolyte with a concentration of 1 mol / L potassium hydroxide (KOH)). The catalytic test results are shown in Figure 6 (a) polarization curve; Figure 6 (b) overpotential at a current density of 10mA / cm²; Figure 6 (c) Tafel curve; Figure 6 (d) linear fit of the capacitance current density (Δj / 2) and the scan rate of the sample at a potential of 0.95 (Vvs.RHE). It should be noted that the silicon carbide / nickel foam sample, cobalt tetroxide / nickel foam sample, cobalt tetroxide / silicon carbide / nickel foam sample, aluminum-cobalt tetroxide / nickel foam sample and aluminum-cobalt tetroxide / silicon carbide / nickel foam sample all contain nickel foam components. In order to simplify the annotation of Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d), nickel foam is omitted in the annotation, that is, silicon carbide / nickel foam is marked as SiC in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d), and cobalt tetroxide / nickel foam is marked as SiC in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d). , Co3O4 is marked in Figure 6(b), Figure 6(c), and Figure 6(d), Co3O4 / SiC is marked in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d), and Al-Co3O4 is marked in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d), and Al-Co3O4 is marked in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d), and Al-Co3O4 is marked in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d), and Al-Co3O4 / SiC is marked in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d).

[0071] First, as shown in Figure 6(a), the linear sweep voltammetry (LSV) curve shows that at 10 mA / cm 2 At the current density, the aluminum-cobalt oxide / silicon carbide / nickel foam electrode has the lowest overpotential; at high current density, the onset potentials of these catalytic electrodes are quite different. Figure 6(b) provides the onset potentials of each group of catalysts at 10 mA / cm 2 The overpotential of each catalyst under current density is only 268mV for the aluminum-cobalt oxide / silicon carbide / nickel foam electrode, which is much lower than the overpotentials of cobalt oxide / nickel foam (327mV), aluminum-cobalt oxide / nickel foam (328mV), cobalt oxide / silicon carbide / nickel foam (354mV) and silicon carbide / nickel foam (488mV).

[0072] This shows that the aluminum-cobalt oxide / silicon carbide / nickel foam electrode has excellent oxygen reduction activity. The Tafel slopes of samples aluminum-cobalt oxide / silicon carbide / nickel foam, aluminum-cobalt oxide / nickel foam, cobalt oxide / silicon carbide / nickel foam, cobalt oxide / nickel foam and silicon carbide / nickel foam are 65.4, 86.2, 88.9, 104.0, 106.6 mVdec, respectively. -1 The sample Al-CoO / SiC / Ni foam has the smallest Tafel slope, indicating its fast reaction kinetics.

[0073] In addition, the double-layer capacitance of each catalyst was determined by cyclic voltammetry at different scan rates in the non-Faraday region. As shown in Figure 6(d), the C dl The values ​​are 46.0, 22.7, 44.9, 45.7 and 3.4 mF / cm 2 , indicating the C of aluminum-cobalt tetroxide / silicon carbide / nickel foam dl The C value of aluminum-cobalt oxide / nickel foam, cobalt oxide / silicon carbide / nickel foam, cobalt oxide / nickel foam and silicon carbide is higher than that of aluminum-cobalt oxide / nickel foam dl The values ​​are large, indicating that it has a large active specific surface area; however, the C dl The value is the smallest, indicating that it has a larger active specific surface area, which is beneficial to improving the performance of oxygen evolution reaction.

[0074] 6. Derivation Model The silicon carbide / nickel foam sample, cobalt oxide / nickel foam sample, aluminum-cobalt oxide / nickel foam sample obtained in Comparative Example 1 and the aluminum-cobalt oxide / silicon carbide / nickel foam composite material sample prepared in Example 1 were subjected to Mott-Schottky (MS) test. Figure 7(a) is the Mott-Schottky curve of the silicon carbide / nickel foam sample, Figure 7(b) is the Mott-Schottky curve of the cobalt oxide / nickel foam sample, Figure 7(c) is the Mott-Schottky curve of the aluminum-cobalt oxide / nickel foam sample, and Figure 7(d) is the Mott-Schottky curve of the aluminum-cobalt oxide / silicon carbide / nickel foam sample. It can be seen that the above four sample materials are P-type semiconductors. It should be noted that the silicon carbide / nickel foam sample, cobalt tetroxide / nickel foam sample, aluminum-cobalt tetroxide / nickel foam sample and aluminum-cobalt tetroxide / silicon carbide / nickel foam sample all contain nickel foam components. In order to simplify the annotation of Figure 7(a), Figure 7(b), Figure 7(c) and Figure 7(d), nickel foam is omitted in the annotation, that is, silicon carbide / nickel foam is marked as SiC in Figure 7(a), cobalt tetroxide / nickel foam is marked as Co3O4 in Figure 7(b), aluminum-cobalt tetroxide / nickel foam is marked as Al-Co3O4 in Figure 7(c), and aluminum-cobalt tetroxide / silicon carbide / nickel foam is marked as Al-Co3O4 / SiC in Figure 7(d).

[0075] Mott-Schottky analysis is used to test the flat-band voltage and majority carrier concentration of the samples (donor concentration for n-type and acceptor concentration for p-type). As shown in Figure 7(a), Figure 7(b), Figure 7(c), and Figure 7(d), the slopes of the samples SiC / Ni foam, CoO / Ni foam, Al-CoO / Ni foam, and Al-CoO / SiC / Ni foam are negative, so the electrodes SiC / Ni foam, CoO / Ni foam, Al-CoO / Ni foam, and Al-CoO / SiC / Ni foam are all p-type semiconductors. The flat-band voltages of SiC / Ni foam, CoO / Ni foam, Al-CoO / Ni foam, and Al-CoO / SiC / Ni foam are 1.0, 0.36, 0.46, and 0.45 V, respectively, and the introduction of SiC does not affect the flat-band voltage. In the aluminum-cobalt oxide / silicon carbide / nickel foam electrode, the two p-type semiconductors of aluminum-cobalt oxide and silicon carbide form a pp-type Schottky heterojunction, and electrons enter aluminum-cobalt oxide from silicon carbide; while a metal-semiconductor contact is formed between silicon carbide and nickel foam, and electrons enter silicon carbide from Ni, that is, a gold-semiconductor contact. In this way, two built-in electric fields are formed, which can accelerate electron transmission.

[0076] It should be noted that the derivation of the model is based on the knowledge of semiconductor physics. The Mott-Schottky electrochemical test method is used to test the semiconductor type of each material. The test results show that aluminum-cobalt tetroxide is a narrow bandgap P-type semiconductor, and silicon carbide is a wide bandgap P-type semiconductor. The two are in contact to form a Schottky junction (pp junction). Similarly, for wide bandgap semiconductor materials, silicon carbide contacts metal nickel to form a gold semi-contact. Both Schottky junctions and gold semi-contacts will form a built-in electric field, which is conducive to electron transmission.

[0077] In the aluminum-cobalt oxide / silicon carbide / nickel foam electrode, silicon carbide / nickel foam forms a gold semi-contact, forming the first built-in electric field, and aluminum-cobalt oxide / silicon carbide forms a Schottky junction, forming a second built-in electric field, that is, the aluminum-cobalt oxide / silicon carbide / nickel foam is a double built-in electric field to accelerate electron transfer, and oxygen is used for preparation. At the same time, the morphology of the aluminum-cobalt oxide / silicon carbide / nickel foam electrode can be changed by changing the concentration of the reaction substance solution.

[0078] It is easy to be understood by those skilled in the art that the above embodiments can be freely combined and superimposed without conflict.

[0079] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A porous metal matrix composite material, characterized in that: The porous metal matrix composite material comprises: A foam skeleton carrier, a reinforcement, and an aluminum-cobalt oxide active nano-matrix, wherein the reinforcement is covered on the foam skeleton carrier, and the aluminum-cobalt oxide active nano-matrix grows on the reinforcement; A metal-semiconductor contact junction is formed between the reinforcement and the foam skeleton carrier, forming a first built-in electric field; a Schottky junction is formed between the aluminum-cobalt tetroxide active nano-matrix and the reinforcement, forming a second built-in electric field.

2. A porous metal matrix composite material according to claim 1, characterized in that: The reinforcement is a wide bandgap material; The aluminum-cobalt tetroxide active nanometer matrix is ​​a narrow bandgap width material.

3. A porous metal matrix composite material according to claim 1, characterized in that: The foam skeleton carrier is a foam metal skeleton; the reinforcement is a semiconductor material; The foam skeleton carrier is at least one of foam nickel, foam aluminum, foam copper and foam titanium; The reinforcement is at least one of silicon carbide, tungsten carbide, titanium carbide, tantalum carbide, boron carbide, zirconium carbide, molybdenum carbide and niobium carbide; The aluminum-cobalt tetroxide active nano matrix comprises a cobalt tetroxide matrix and an active material, wherein the active material is doped in the cobalt tetroxide matrix; The active material is at least one of aluminum and an aluminum-based alloy.

4. A method for preparing a porous metal-based composite material, characterized in that: Used to prepare a porous metal-based composite material as claimed in any one of claims 1 to 3, the preparation method comprising: Pre-treating the foam skeleton carrier; Plasma treating the foam skeleton carrier to activate the foam skeleton carrier; Performing magnetron sputtering treatment on the activated foam skeleton carrier to deposit a reinforcement on the surface of the activated foam skeleton carrier; The aluminum source and the cobalt source are configured into a mixed solution according to a certain ratio; The foam skeleton carrier after the reinforcement body is deposited is immersed in the mixed solution to carry out a hydrothermal reaction, and the porous metal-based composite material is obtained after the reaction is completed.

5. The method for preparing a porous metal-based composite material according to claim 4, characterized in that: The pretreatment of the foam skeleton carrier comprises the steps of: Cutting the foam skeleton carrier, placing the foam skeleton carrier in a container filled with deionized water or an organic solvent, placing the container in an ultrasonic cleaning machine, and cleaning at a cleaning frequency of 40kHz to 80kHz for 15min to 30min; After cleaning, the foam skeleton carrier is taken out, rinsed with alcohol, blown dry with nitrogen, and then dried at low temperature.

6. The method for preparing a porous metal-based composite material according to claim 4, characterized in that: The plasma treatment of the foam skeleton carrier to activate the foam skeleton carrier comprises the steps of: The foam skeleton carrier is placed in oxygen plasma and treated in an oxygen plasma atmosphere at a temperature of 300° C. to 700° C., so that oxygen-containing compounds grow on the foam skeleton carrier.

7. The method for preparing a porous metal-based composite material according to claim 4, characterized in that: The method of subjecting the activated foam skeleton carrier to magnetron sputtering treatment to deposit a reinforcement on the surface of the activated foam skeleton carrier comprises the following steps: The foam skeleton carrier treated with plasma is placed in a magnetron sputtering device, the target material is installed, and the protective gas is introduced. Under the conditions of a pressure of 3 Pa, a flow rate of 45 sccm, a voltage of 18 V, and a current of 8 A, the magnetron sputtering treatment is carried out for 10 min to 40 min, and a reinforcement with a thickness of 80 nm to 120 nm is grown on the surface of the activated foam skeleton carrier.

8. The method for preparing a porous metal-based composite material according to claim 4, characterized in that: The method of preparing a mixed solution of an aluminum source and a cobalt source in a certain proportion comprises the following steps: 15 mL of deionized water and 15 mL of ethanol were measured and mixed and stirred evenly, and 3 mmol of cobalt nitrate hexahydrate, 15 mmol of urea, and 3.9 mmol of ammonium fluoride were added in sequence, and stirred to dissolve to obtain solution A; 0.025 g of AlCl 3 (4 wt %) was added to solution A, and the mixture was stirred to dissolve, thereby obtaining a mixed solution B, which was used as a reaction solution for the hydrothermal reaction.

9. The method for preparing a porous metal-based composite material according to claim 4, characterized in that: The steps of immersing the foam skeleton carrier after depositing the reinforcement into the mixed solution to perform a hydrothermal reaction, and obtaining the porous metal-based composite material after the reaction is completed include: The mixed solution is transferred to a reaction kettle, the foam skeleton carrier after the deposition reinforcement is placed in the reaction kettle, and the mixture is kept at a temperature of 80° C. to 150° C. for 6 h to 10 h before being taken out; The porous metal-based composite material is obtained by repeatedly washing with deionized water and alcohol and drying.

10. An application of a porous metal matrix composite material, characterized in that: The porous metal-based composite material as claimed in any one of claims 1 to 3 is used as an electrode for electrocatalytic reaction.

Images