A porous metal matrix composite material, its preparation method and application

Abstract

The present application provides a porous metal matrix composite material, its preparation method and application, belonging to the field of electrocatalytic technology, including: in-situ growing a reinforcing body and an aluminum-cobalt tetroxide active nano matrix on a foam skeleton carrier in sequence; using the foam skeleton carrier as a matrix and forming a composite material by in-situ growth, which has a relatively high specific surface area, increases the active sites on the material, enables the electrolyte to fully contact with the active substances, and has stronger catalytic properties; the contact interface between the reinforcing body and the foam skeleton carrier forms a metal-semiconductor contact, constituting a first built-in electric field within the overall structure; the contact interface between the reinforcing body and the aluminum-cobalt tetroxide active nano matrix forms a Schottky junction, constituting a second built-in electric field within the overall structure. By accelerating electron transport through the double built-in electric fields, the oxygen evolution reaction (OER) efficiency of the material can be improved, meeting the requirements of electrocatalysis.

Description

Technical Field

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

[0002] Metal-ceramic matrix composites generally use active metal materials as the matrix and ceramic materials as the reinforcing phase. Although they combine the advantages of light weight, good electrical conductivity and thermal conductivity of metals, and high hardness, high wear resistance, low thermal expansion coefficient and good chemical stability of ceramics, and have broad application prospects in the fields of aerospace, electronic packaging, automotive manufacturing, etc., 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 technologies.

[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 preparation method of a porous metal-based composite material.

[0006] A 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 the embodiments of the present application, a porous metal-based composite material is provided, including:

[0008] A foam skeleton carrier, a reinforcing body, and an aluminum-cobalt tetroxide active nanomatrix, the reinforcing body covers the foam skeleton carrier, and the aluminum-cobalt tetroxide active nanomatrix grows on the reinforcing body;

[0009] A metal-semiconductor contact junction is formed between the reinforcing body and the foam skeleton carrier to constitute a first built-in electric field; a Schottky junction is formed between the aluminum-cobalt tetroxide active nanomatrix and the reinforcing body to constitute a second built-in electric field.

[0010] In a feasible embodiment, the reinforcing body is a wide bandgap material;

[0011] The aluminum-cobalt tetroxide active nanomatrix is a narrow bandgap material.

[0012] In a feasible embodiment, the foam skeleton carrier is a foam metal skeleton; the reinforcing body is a semiconductor material;

[0013] The foam skeleton carrier is at least one of foam nickel, foam aluminum, foam copper, and foam titanium;

[0014] The reinforcing body is at least one of silicon carbide, tungsten carbide, titanium carbide, tantalum carbide, boron carbide, zirconium carbide, molybdenum carbide, and niobium carbide;

[0015] The aluminum-cobalt tetroxide active nano matrix includes a cobalt tetroxide matrix and an active material, and the active material is doped in the cobalt tetroxide matrix;

[0016] The active material is at least one of aluminum and aluminum-based alloys.

[0017] According to the second aspect of the embodiments of the present application, a method for preparing a porous metal matrix composite is provided, which is used to prepare the porous metal matrix composite according to any one of the above technical solutions, including:

[0018] Pre-treat the foam skeleton carrier;

[0019] Perform plasma treatment on the foam skeleton carrier to activate the foam skeleton carrier;

[0020] Perform magnetron sputtering treatment on the activated foam skeleton carrier to deposit a reinforcing body on the surface of the activated foam skeleton carrier;

[0021] Configure an aluminum source and a cobalt source into a mixed solution according to a certain ratio;

[0022] Immerse the foam skeleton carrier deposited with the reinforcing body in the mixed solution, perform a hydrothermal reaction, and obtain a porous metal matrix composite after the reaction ends.

[0023] In a feasible implementation manner, pre-treating the foam skeleton carrier includes the steps of:

[0024] Cut the foam skeleton carrier, place the foam skeleton carrier in a container filled with deionized water or an organic solvent, place the container in an ultrasonic cleaner, and clean it for 15 min to 30 min at a cleaning frequency of 40 kHz to 80 kHz;

[0025] After the cleaning is completed, take out the foam skeleton carrier, rinse it with alcohol, dry it with nitrogen, and then perform low-temperature drying.

[0026] In a feasible implementation manner, performing plasma treatment on the foam skeleton carrier to activate the foam skeleton carrier includes the steps of:

[0027] Place the foam skeleton carrier in an oxygen plasma, and perform oxygen plasma atmosphere treatment at a temperature of 300 °C to 700 °C to grow an oxygen-containing compound on the foam skeleton carrier.

[0028] In a feasible implementation manner, performing magnetron sputtering treatment on the activated foam skeleton carrier to deposit a reinforcing body on the surface of the activated foam skeleton carrier includes the steps of:

[0029] Put the plasma-treated foam skeleton carrier into a magnetron sputtering device, install the target, introduce the protective gas, and perform 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 an enhancer with a thickness of 80 nm to 120 nm on the surface of the activated foam skeleton carrier.

[0030] In a feasible implementation manner, measure 15 mL of deionized water and 15 mL of ethanol, mix and stir evenly, and sequentially add 3 mmol of cobalt nitrate hexahydrate, 15 mmol of urea, and 3.9 mmol of ammonium fluoride, and stir to dissolve to obtain solution A;

[0031] Add 0.025 g of AlCl3 (4 wt%) to solution A, stir to dissolve to obtain a mixed solution B, and the mixed solution B is used as the reaction solution for the hydrothermal reaction.

[0032] In a feasible implementation manner, immerse the foam skeleton carrier after depositing the enhancer in the mixed solution and perform a hydrothermal reaction. After the reaction ends, a porous metal matrix composite material is obtained. The steps include:

[0033] Transfer the mixed solution to a reaction kettle, put the foam skeleton carrier after depositing the enhancer, and take it out after heat preservation at a temperature of 80 °C to 150 °C for 6 h to 10 h;

[0034] Wash repeatedly with deionized water and alcohol, and dry to obtain a porous metal matrix composite material.

[0035] According to the third aspect of the embodiments of the present application, an application of a porous metal matrix composite material is proposed, and the porous metal matrix composite material in any of the above technical solutions is used as an electrode for an electrocatalytic reaction.

[0036] A porous metal matrix composite material, a preparation method and an application thereof according to the present application have the following beneficial effects compared with the prior art:

[0037] The porous metal matrix composite provided by the embodiment of the present application includes a foam skeleton carrier, a reinforcing body, and an aluminum-cobalt tetroxide active nano matrix. The reinforcing body and the aluminum-cobalt tetroxide active nano matrix are in-situ grown on the foam skeleton carrier in sequence. Using the foam skeleton carrier as the matrix and forming the composite material by in-situ growth, it has a relatively high specific surface area, increases the active sites on the material, enables the electrolyte to fully contact with the active substances, and has stronger catalytic properties. The contact interface between the reinforcing body and the foam skeleton carrier forms a metal-semiconductor contact, constituting a first built-in electric field within the overall structure. The contact interface between the reinforcing body and the aluminum-cobalt tetroxide active nano matrix forms a Schottky junction, constituting a second built-in electric field within the overall structure. By accelerating electron transport through the double built-in electric fields, the oxygen evolution reaction efficiency of the material for oxygen production can be improved to meet the requirements of electrocatalysis. Description of the Drawings

[0038] By reading the following detailed description of the preferred embodiments, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0039] Figure 1 It is a schematic step flow chart of a preparation method of a porous metal matrix composite according to an embodiment provided by the present application;

[0040] Figure 2 It is a scanning electron microscope image of the sample obtained in Example 1 and all the samples obtained in Comparative Example 1;

[0041] Figure 3 It is an X-ray diffraction pattern of the sample obtained in Example 1 and some of the samples obtained in Comparative Example 1;

[0042] Figure 4 It is a Raman spectrum of the sample obtained in Example 1 and some of the samples obtained in Comparative Example 1;

[0043] Figure 5(a) is an X-ray photoelectron spectrum of the Co 2p orbital of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite sample, the aluminum-cobalt tetroxide / nickel foam sample, the cobalt tetroxide / silicon carbide / nickel foam sample, and the cobalt tetroxide / nickel foam sample;

[0044] Figure 5(b) is an X-ray photoelectron spectrum of the O 1s orbital of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite sample, the aluminum-cobalt tetroxide / nickel foam sample, the cobalt tetroxide / silicon carbide / nickel foam sample, and the cobalt tetroxide / nickel foam sample;

[0045] Figure 5(c) shows the X-ray photoelectron spectroscopy diagrams of the Ni 3p and Al 2p orbits of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite sample and the aluminum-cobalt tetroxide / nickel foam sample;

[0046] Figure 5(d) shows the X-ray photoelectron spectroscopy diagram of the Si 2p orbit of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite sample and the cobalt tetroxide / silicon carbide / nickel foam sample;

[0047] Figure 6(a) shows the polarization curves of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite sample, the aluminum-cobalt tetroxide / nickel foam sample, the cobalt tetroxide / silicon carbide / nickel foam sample, the cobalt tetroxide / nickel foam sample, and the silicon carbide / nickel foam sample;

[0048] Figure 6(b) shows the bar graph of the overpotential of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite sample, the aluminum-cobalt tetroxide / nickel foam sample, the cobalt tetroxide / silicon carbide / nickel foam sample, the cobalt tetroxide / nickel foam sample, and the silicon carbide / nickel foam sample at a current density of 10 mA / cm²;

[0049] Figure 6(c) shows the Tafel curves of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite sample, the aluminum-cobalt tetroxide / nickel foam sample, the cobalt tetroxide / silicon carbide / nickel foam sample, the cobalt tetroxide / nickel foam sample, and the silicon carbide / nickel foam sample;

[0050] Figure 6(d) shows the linear fitting diagram of the capacitive current density and the scanning rate of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite sample, the aluminum-cobalt tetroxide / nickel foam sample, the cobalt tetroxide / silicon carbide / nickel foam sample, the cobalt tetroxide / nickel foam sample, and the silicon carbide / nickel foam sample;

[0051] Figure 7(a) shows the Mott-Schottky curve of the silicon carbide / nickel foam sample;

[0052] Figure 7(b) shows the Mott-Schottky curve of the cobalt tetroxide / nickel foam sample;

[0053] Figure 7(c) shows the Mott-Schottky curve of the aluminum-cobalt tetroxide / nickel foam sample;

[0054] Figure 7(d) shows the Mott-Schottky curve of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite sample. Detailed implementation manners

[0055] The preferred embodiments of the present application are described below with reference to 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.

[0056] According to the first aspect of the embodiments of the present application, a porous metal matrix composite material is provided, including: a foam skeleton carrier, a reinforcing body, and an aluminum-cobalt tetroxide active nanomatrix. The reinforcing body covers the foam skeleton carrier, and the aluminum-cobalt tetroxide active nanomatrix grows on the reinforcing body; a metal-semiconductor contact junction is formed between the reinforcing body and the foam skeleton carrier, constituting a first built-in electric field; a Schottky junction is formed between the aluminum-cobalt tetroxide active nanomatrix and the reinforcing body, constituting a second built-in electric field.

[0057] The porous metal matrix composite material provided by the embodiments of the present application includes a foam skeleton carrier, a reinforcing body, and an aluminum-cobalt tetroxide active nanomatrix. The reinforcing body and the aluminum-cobalt tetroxide active nanomatrix are in-situ grown on the foam skeleton carrier in sequence; using the foam skeleton carrier as the matrix and forming the composite material by in-situ growth has a relatively high specific surface area, increasing the active sites on the material, enabling the electrolyte to fully contact the active substances, and having stronger catalytic properties; the contact interface between the reinforcing body and the foam skeleton carrier forms a metal-semiconductor contact, constituting a first built-in electric field within the overall structure; the contact interface between the reinforcing body and the aluminum-cobalt tetroxide active nanomatrix forms a Schottky junction, constituting a second built-in electric field within the overall structure. By accelerating electron transport through the double built-in electric fields, the oxygen evolution reaction (OER) efficiency of the material can be improved to meet the requirements of electrocatalysis.

[0058] In a feasible implementation manner, the reinforcing body is a wide bandgap semiconductor material; the aluminum-cobalt tetroxide active nanomatrix is a narrow bandgap semiconductor material.

[0059] In this technical solution, a wide bandgap semiconductor material is magnetron sputtered on the surface of the foam skeleton carrier to form a reinforcing body on the surface of the foam skeleton carrier. The wide bandgap semiconductor material provides chemical stability and thermal stability, enabling the reinforcing body to maintain its structural integrity under harsh reaction conditions, providing stable support for the subsequently grown aluminum-cobalt tetroxide active nanomatrix, and preventing the aluminum-cobalt tetroxide active nanomatrix from undergoing structural damage or performance degradation during the reaction process; then a layer of narrow bandgap semiconductor material is grown on the surface of the wide bandgap semiconductor material to grow the aluminum-cobalt tetroxide active nanomatrix on the surface of the reinforcing body. The aluminum-cobalt tetroxide active nanomatrix grows on the wide bandgap material, forming double built-in electric fields, namely metal-semiconductor contact junctions and Schottky junctions, within the material structure. Thus, by accelerating electron transport through the double built-in electric fields, the oxygen evolution reaction efficiency of the material can be improved, enabling the composite material to be applied in the field of electrocatalysis.

[0060] In a feasible implementation manner, the foam skeleton carrier is a foam metal skeleton; the reinforcing body is a semiconductor material; the foam skeleton carrier is at least one of nickel foam, aluminum foam, copper foam and titanium foam; the reinforcing body adopts a carbide material, and the reinforcing body 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 includes a cobalt tetroxide matrix and an active material, and the active material is doped in the cobalt tetroxide matrix; the active material is at least one of aluminum and aluminum-based alloys.

[0061] In this technical solution, the reinforcing body adopts a semiconductor material, and the foam skeleton carrier adopts a foam metal skeleton, so that a metal-semiconductor contact is formed at the contact interface between the reinforcing body and the foam skeleton carrier, constituting a first built-in electric field; the foam metal skeleton has a good three-dimensional porous network structure, providing stable physical support for the entire material system, enabling the subsequently grown reinforcing body aluminum-cobalt tetroxide active nano matrix to stably adhere, maintaining the overall shape of the material, and preventing 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, enabling more active sites to be exposed to the reaction environment, which is conducive to the full contact between the reactants and the aluminum-cobalt tetroxide active nano matrix, thereby improving the reaction rate and catalytic activity and enhancing the catalytic performance of the composite material. Doping aluminum or an aluminum-based alloy into the cobalt tetroxide matrix can change the electron cloud distribution and energy band structure of the cobalt tetroxide matrix, reduce the resistance, improve the carrier mobility, thereby enhancing 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 new active sites, interact with the cobalt tetroxide matrix, increasing the number of sites that can adsorb and activate the reactants, further improving the catalytic activity of the material and the selectivity of the target reaction; at the same time, the doping of aluminum or an aluminum-based alloy can also enhance the structural stability of the cobalt tetroxide matrix. During the reaction process, aluminum or an aluminum-based alloy can form an Al-O-Co interfacial chemical bond with the cobalt tetroxide matrix and regulate the oxygen vacancies, enabling the aluminum-cobalt tetroxide to have 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 transformation of the cobalt tetroxide matrix, and enabling the cobalt tetroxide active nano matrix to maintain good performance during a long-term reaction process.

[0062] As a preferred solution, the foam skeleton carrier is selected as nickel foam (Ni-foam), and the reinforcing body is selected as magnetron sputtered silicon carbide (SiC). The silicon carbide / nickel foam forms a metal-semiconductor contact, and aluminum-cobalt tetroxide / silicon carbide forms a Schottky junction. Two built-in electric fields are constructed in the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite structure to accelerate electron transport, enabling the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite to be applicable to the field of electrocatalysis. Specifically, the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite nanowires form a lily shape, significantly increasing the active sites. The large number of active sites allows the electrolyte to come into full contact with the active substances, which is beneficial to improving the efficiency of the catalytic reaction.

[0063] As Figure 1 shown, according to the second aspect of the present application, a method for preparing a porous metal-based composite material is proposed for preparing the porous metal-based composite material according to any one of the above technical solutions. The preparation method includes:

[0064] Step 100: Pretreat the foam skeleton carrier; remove impurities on the surface of the foam skeleton carrier to improve the bonding force between the foam skeleton carrier and the reinforcing body, thereby ensuring the quality and performance of the reinforcing body material grown on the foam skeleton carrier subsequently.

[0065] Step 200: Treat the foam skeleton carrier with plasma to activate the foam skeleton carrier; place 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 reinforcing body, and enhance the bonding force between the foam skeleton carrier and the reinforcing body, so as to better grow the reinforcing body on the surface of the foam skeleton carrier.

[0066] Step 300: Perform magnetron sputtering treatment on the activated foam skeleton carrier to deposit the reinforcing body on the surface of the activated foam skeleton carrier; place the foam skeleton carrier treated with plasma into a magnetron sputtering device for magnetron sputtering treatment to grow the reinforcing body on the surface of the foam skeleton carrier, forming a composite material in which the reinforcing body is combined with the foam skeleton carrier.

[0067] Step 400: Configure a mixed solution from an aluminum source and a cobalt source in a certain proportion; precisely control the concentrations of aluminum ions and cobalt ions in the mixed solution to precisely control the growth rate and quality of the active material in the subsequent reaction, thereby realizing the regulation of the composition and performance of the final product.

[0068] Step 500: Immerse the foam skeleton carrier deposited with the reinforcing body in the mixed solution for hydrothermal reaction, and obtain the porous metal-based composite material after the reaction ends; through the hydrothermal reaction, the catalytically active aluminum-cobalt tetroxide active nano matrix, the reinforcing body with a supporting and protecting effect, and the foam skeleton carrier as the substrate are combined together to form the porous metal-based composite material.

[0069] Through the preparation method of the porous metal matrix composite material provided by the embodiments of the present application, with the foam skeleton carrier as the matrix, in-situ growth is carried out on the plasma-treated foam skeleton carrier by using magnetron sputtering and hydrothermal reaction methods to form a porous metal matrix composite material. Not only a double built-in electric field is formed within the composite material structure, accelerating the electron transport and capable of improving the oxygen evolution reaction (OER) efficiency of oxygen production; moreover, by changing the concentrations of the aluminum source and the cobalt source in the mixed solution, the interface and the electron state density between the composite materials can be controlled, and then the morphology of the porous metal matrix composite material can be controlled, so that the porous metal matrix composite material can meet the catalytic requirements in the field of electrocatalysis.

[0070] The existing preparation methods of metal-ceramic matrix composite materials include powder metallurgy method, in-situ generation method and mechanical stirring method. Taking the aluminum-cobalt ferrite / silicon carbide composite material as an example:

[0071] Powder metallurgy method: First, aluminum powder, cobalt ferrite powder and silicon carbide powder are uniformly mixed in a ball milling tank in a certain proportion, which can be dry mixed or wet mixed. The mixed powder is cold pressed into a blank, vacuum degassed, hot pressed and sintered, and subsequent extrusion, rolling, heat treatment, etc. are carried out to obtain the composite material. It can regulate the size and content of the reinforcement and ensure its uniform distribution in the matrix, but the process is cumbersome, requires specific working conditions, and improper sintering temperature will lead to segregation.

[0072] In-situ generation method: Select appropriate reactants, and heat up in a specific environment to make the elements in the raw materials undergo physical and chemical reactions, and uniformly distributed cobalt ferrite and silicon carbide reinforcements are generated inside the material. The advantages are that the reinforcements are uniformly distributed, the interface is clean, and the process is simple, but there are requirements for raw materials, the reaction by-products are difficult to control, and there are interface problems.

[0073] Mechanical stirring method: During the stirring process, cobalt ferrite and silicon carbide particles are added to liquid aluminum, and a high-speed rotating stirring device is used to make them uniformly mixed, and then poured into a mold. The operation is simple and the cost is low. There are two methods of liquid stirring and semi-solid stirring. Semi-solid stirring can make the distribution of the reinforcement particles more uniform.

[0074] The above three methods for preparing the aluminum-cobalt tetroxide / silicon carbide composite material are multi-component composite materials with aluminum as the matrix and cobalt tetroxide and silicon carbide as the reinforcing phases. Although they combine the advantages of aluminum such as light weight, good electrical and thermal conductivity, 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 electron state density between the prepared aluminum-cobalt tetroxide / silicon carbide composite materials cannot be regulated, and the morphology is uncontrollable. In-situ growth cannot be achieved, the shape of the electrode cannot be changed arbitrarily, and it cannot be used in the field of electrocatalysis. In this application, a method combining magnetron sputtering and hydrothermal reaction is used to in-situ grow aluminum-cobalt tetroxide / silicon carbide on a plasma-treated foam skeleton carrier. By changing the concentrations of the aluminum source and cobalt source in the mixed solution, the interface and electron state density between the composite materials can be controlled, and then the morphology of the porous metal matrix composite material can be controlled, so that the porous metal matrix composite material can meet the catalytic requirements in the field of electrocatalysis.

[0075] In a feasible implementation manner, the pretreatment of the foam skeleton carrier includes 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 cleaner, and cleaning for 15 min to 30 min at a cleaning frequency of 40 kHz to 80 kHz; after the cleaning is completed, taking out the foam skeleton carrier, rinsing it clean with alcohol, drying it with nitrogen, and then performing low-temperature drying.

[0076] In this technical solution, ultrasonic cleaning with deionized water or an organic solvent can effectively remove impurities on the foam skeleton carrier to ensure the quality and performance of the material that grows on the foam skeleton carrier subsequently; by drying the foam skeleton carrier in a timely manner, it is possible to avoid the foam skeleton carrier adsorbing impurities in the air and at the same time avoid corrosion of the foam skeleton carrier; when the dried foam skeleton carrier is subjected to plasma atmosphere treatment, it can better match other materials or process conditions, which is beneficial to improving the uniformity and stability of the effects of plasma treatment and magnetron sputtering treatment.

[0077] Furthermore, weak acids, weak bases, or neutral organic solvents such as ethanol and acetone can be used to clean the foam skeleton carrier.

[0078] In a feasible implementation manner, plasma treatment of the foam skeleton carrier is performed to activate the foam skeleton carrier, including the steps of: placing the foam skeleton carrier in oxygen plasma and performing oxygen plasma atmosphere treatment at a temperature of 300 °C to 700 °C to grow oxygen groups on the foam skeleton carrier.

[0079] In this technical solution, the foam skeleton carrier is placed in an oxygen plasma atmosphere at 300°C to 700°C for treatment, so as to grow oxygen groups on the surface of the foam skeleton carrier, enabling the reinforcement to form a strong coupling with the surface of the foam skeleton carrier and improving the adhesion of the reinforcement growth.

[0080] In some examples, when the foam skeleton carrier is nickel foam and the reinforcement is silicon carbide, by treating the nickel foam in an oxygen plasma atmosphere, oxygen groups grow on the nickel foam, forming Ni-O bonds and Ni-OH bonds, so that silicon carbide can form a strong coupling with the surface of the nickel foam, improving the adhesion of silicon carbide and ensuring the structural stability and reliability after the combination of silicon carbide and nickel foam.

[0081] In a feasible implementation manner, magnetron sputtering treatment is performed on the activated foam skeleton carrier, and the reinforcement is deposited on the surface of the activated foam skeleton carrier, including the steps of: placing the plasma-treated foam skeleton carrier into a magnetron sputtering device, installing a target, 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 with a thickness of 80 nm to 120 nm on the surface of the activated foam skeleton carrier.

[0082] In this technical solution, the conditions of the magnetron sputtering treatment are precisely controlled to grow a reinforcement with a preset thickness on the surface of the foam skeleton carrier, obtain a composite material of the reinforcement and the foam skeleton carrier, and form a metal-semiconductor contact junction between the foam skeleton carrier and the reinforcement to constitute a first built-in electric field.

[0083] As a preferred solution, a high-purity silicon carbide ceramic target is installed, argon is introduced as a protective gas, and the activated nickel foam is magnetron sputtered for 10 minutes, and 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.

[0084] In a feasible implementation manner, an aluminum source and a cobalt source are configured into a mixed solution according to a certain ratio, including the steps of: measuring 15 mL of deionized water and 15 mL of ethanol, mixing and stirring evenly, and successively adding 3 mmol (millimoles) of cobalt nitrate hexahydrate, 15 mmol of urea, and 3.9 mmol of ammonium fluoride, 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 the reaction solution for the hydrothermal reaction.

[0085] In this technical solution, the concentrations of aluminum ions and cobalt ions are precisely controlled to control the interface and electron state density between the aluminum-cobalt tetroxide active nanomatrix and the reinforcing body during the subsequent growth of the aluminum-cobalt tetroxide active nanomatrix, thereby making the morphology of the subsequent grown aluminum-cobalt tetroxide active nanomatrix controllable, so as to control the in-situ growth of aluminum-cobalt tetroxide active nanomatrices with specific shapes on the foam skeleton carrier and the reinforcing body.

[0086] In this technical solution, the morphology regulation of the aluminum-cobalt tetroxide / silicon carbide / nickel foam electrode can be achieved by changing the concentration of the reactant solution. The morphology of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material prepared with the mixed solution of this ratio is regular, and the nanowires form a lily shape. Furthermore, the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material has a high specific surface area, increasing the active sites of the composite material. As a result, the electrolyte can fully contact the active substances, improving the catalytic efficiency.

[0087] It should be noted that in the field of electrocatalysis, the morphology and interface electron state density of the electrode directly determine the catalytic activity, stability, and mass transfer efficiency of the electrode. During in-situ growth, by dynamically regulating the growth process of the aluminum-cobalt tetroxide material, the morphology control and interface electron structure optimization of the composite material can be achieved, thereby changing the electrode shape and breaking through the limitation that traditional composite materials cannot be applied in the field of electrocatalysis due to the difficulty in controlling the morphology.

[0088] In a feasible implementation, the foam skeleton carrier after depositing the reinforcing body is immersed in the mixed solution for hydrothermal reaction. After the reaction ends, a porous metal matrix composite material is obtained. The steps include: transferring the mixed solution B to the reaction kettle, putting in the foam skeleton carrier after depositing the reinforcing body, keeping it at a temperature of 80°C to 150°C for 6h to 10h, and then taking it out; repeatedly washing with deionized water and alcohol, and drying to obtain the porous metal matrix composite material.

[0089] In this technical solution, the mixed solution is transferred to the reaction kettle, and the foam skeleton carrier after plasma treatment is put in for hydrothermal reaction to in-situ grow aluminum-cobalt tetroxide active nanomatrices on the reinforcing body; then, the composite material is taken out after keeping it at a temperature of 80°C to 150°C for 6h to 10h, and after repeatedly washing and drying, a porous metal matrix composite material is obtained.

[0090] As a preferred solution, the mixed solution is transferred to the reaction kettle, and the plasma-treated nickel foam is put in for hydrothermal reaction to in-situ grow aluminum-cobalt tetroxide active nanomatrices on the silicon carbide reinforcing body; then, the composite material is taken out after keeping it at a temperature of 120°C for 8h, and after repeatedly washing and drying, an aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material is obtained.

[0091] It can be understood that the preparation method of the porous metal matrix composite material provided by the embodiments of the present application, because it is applied to the porous metal matrix composite material of any of the above technical solutions, so the preparation method of the porous metal matrix composite material has all the beneficial effects of the porous metal matrix composite material of the above technical solutions, which will not be elaborated here.

[0092] According to the third aspect of the present application, an application of a porous metal matrix composite material is proposed, and the porous metal matrix composite material of any one of the above technical solutions is used as an electrode for an electrocatalytic reaction.

[0093] It can be understood that the application of the porous metal matrix composite material provided by the embodiments of the present application, because it includes the porous metal matrix composite material of any of the above technical solutions, so the preparation method of the porous metal matrix composite material has all the beneficial effects of the porous metal matrix composite material of the above technical solutions, which will not be elaborated here.

[0094] Example 1

[0095] The specific preparation method of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material is as follows:

[0096] 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, then put the container into an ultrasonic cleaner, and clean it for 30 minutes at a cleaning frequency of 60 kHz; after cleaning, take out the nickel foam, rinse it with alcohol, dry it with nitrogen, and then dry the nickel foam at a low temperature in a vacuum drying oven;

[0097] Step 200': Treat the nickel foam in an oxygen plasma atmosphere at 300 °C to grow nickel oxide on the surface of the nickel foam;

[0098] Step 300': Put the plasma-treated nickel foam into a magnetron sputtering device, install a silicon carbide target, introduce Ar, and perform magnetron sputtering for 10 minutes under the parameter settings of 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 to obtain a silicon carbide / nickel foam composite material;

[0099] Measure 15 mL of deionized water and 15 mL of ethanol, mix and stir evenly, and sequentially add 3 mmol of cobalt nitrate hexahydrate (0.873 g), 15 mmol of urea, and 3.9 mmol of ammonium fluoride, stir and dissolve to obtain solution A; then add 0.025 g of AlCl3 (4 wt%) to solution A, stir and dissolve to obtain a mixed solution B;

[0100] Step 500': Transfer the mixed solution B into a reaction kettle, put in silicon carbide / nickel foam (nickel foam after plasma treatment), keep it at 120 °C for 8 hours, then take it out, and repeatedly wash it with deionized water and alcohol. After drying, an aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material sample is obtained.

[0101] Comparative Example 1

[0102] Samples of five materials, namely nickel foam, silicon carbide / nickel foam, cobalt tetroxide / nickel foam, aluminum-cobalt tetroxide / nickel foam, and cobalt tetroxide / silicon carbide / nickel foam, were prepared and compared with the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material sample prepared in Example 1.

[0103] The specific preparation method of nickel foam is as follows: Cut the nickel foam into rectangles with a size of 1.2 cm × 1.5 cm, put the nickel foam into an appropriate amount of deionized water, then put the container into an ultrasonic cleaner, and clean it for 30 minutes at a cleaning frequency of 60 kHz; after cleaning, take out the nickel foam, rinse it with alcohol, dry it with nitrogen, and then dry the nickel foam at a low temperature in a vacuum drying oven; put the nickel foam into an oxygen plasma atmosphere at 300 °C for treatment to grow nickel oxide on the surface of the nickel foam, and obtain a nickel foam sample.

[0104] The preparation method of silicon carbide / nickel foam is as follows: Cut the nickel foam into rectangles with a size of 1.2 cm × 1.5 cm, put the nickel foam into an appropriate amount of deionized water, then put the container into an ultrasonic cleaner, and clean it for 30 minutes at a cleaning frequency of 60 kHz; after cleaning, take out the nickel foam, rinse it with alcohol, dry it with nitrogen, and then dry the nickel foam at a low temperature in a vacuum drying oven; put the nickel foam into an oxygen plasma atmosphere at 300 °C for treatment to grow nickel oxide on the surface of the nickel foam, and obtain nickel foam; put the plasma-treated nickel foam into a magnetron sputtering device, install a silicon carbide target, introduce Ar, and perform magnetron sputtering for 10 minutes under the parameter settings of 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, and obtain a silicon carbide / nickel foam composite material sample.

[0105] The specific preparation method of cobalt tetroxide / silicon carbide / nickel foam is as follows: On the basis of obtaining the silicon carbide / nickel foam composite material, measure 15 mL of deionized water and 15 mL of ethanol, mix and stir evenly, and sequentially add 3 mmol of cobalt nitrate hexahydrate (0.873 g), 15 mmol of urea, and 3.9 mmol of ammonium fluoride, and stir to dissolve to obtain solution A; transfer solution A into a reaction kettle, put in silicon carbide / nickel foam, keep it at 120 °C for 8 hours, then take it out, and repeatedly wash it with deionized water and alcohol. After drying, a cobalt tetroxide / silicon carbide / nickel foam composite material sample is obtained.

[0106] The specific preparation method of cobalt tetroxide / nickel foam is as follows: On the basis of obtaining the nickel foam after plasma treatment, 15 mL of deionized water and 15 mL of ethanol are measured, 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 are added in sequence, stirred and dissolved to obtain solution A; Solution A is transferred to a reaction kettle, the nickel foam after plasma treatment is put in, taken out after heat preservation at 120 °C for 8 hours, and repeatedly washed with deionized water and alcohol, and dried to obtain a cobalt tetroxide / nickel foam composite material sample.

[0107] The specific preparation method of aluminum-cobalt tetroxide / nickel foam is as follows: On the basis of obtaining the nickel foam after plasma treatment, 15 mL of deionized water and 15 mL of ethanol are measured, 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 are added in sequence, stirred and dissolved to obtain solution A; Then 0.025 g of AlCl3 (4 wt%) is added to solution A, stirred and dissolved to obtain a mixed solution B; The mixed solution B is transferred to a reaction kettle, the cut nickel foam after plasma treatment is put in, taken out after heat preservation at 120 °C for 8 hours, and repeatedly washed with deionized water and alcohol, and dried to obtain an aluminum-cobalt tetroxide / nickel foam composite material sample.

[0108] 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 and the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material sample prepared in Example 1 obtained in Comparative Example 1 are subjected to characterization analysis, catalytic performance test and model derivation:

[0109] 1. Scanning electron microscope (SEM) characterization

[0110] 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 and the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material sample prepared in Example 1 obtained in Comparative Example 1 are characterized by scanning electron microscope. Figure 2 Scanning electron microscope photos of six sample materials of nickel foam, silicon carbide / nickel foam, cobalt tetroxide / nickel foam, aluminum-cobalt tetroxide / nickel foam, cobalt tetroxide / silicon carbide / nickel foam and aluminum-cobalt tetroxide / silicon carbide / nickel foam. In Figure 2Among them, (a1) and (a2) are the scanning electron microscope characterizations of the nickel foam samples, (b1) and (b2) are the scanning electron microscope characterizations of the silicon carbide / nickel foam composite samples, (c1) and (c2) are the scanning electron microscope characterizations of the cobalt tetroxide / nickel foam composite samples, (d1) and (d2) are the scanning electron microscope characterizations of the aluminum-cobalt tetroxide / nickel foam composite samples, (e1) and (e2) are the scanning electron microscope characterizations of the cobalt tetroxide / silicon carbide / nickel foam composite samples, and (f1) and (f2) are the scanning electron microscope characterizations of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite samples.

[0111] It can be seen from the scanning electron microscope characterizations of the six samples that the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite has the largest specific surface area and a natural shape. By controlling the interface and electron state density between the aluminum-cobalt tetroxide / silicon carbide / nickel foam composites, the morphology of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composites is regular, and the nanowires of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composites form a lily shape, with a significant increase in active sites. In the electrocatalytic reaction, by controlling the in-situ growth, the shape of the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite electrode can be changed arbitrarily. A large number of active sites enable the electrolyte to come into full contact with the active substances, which is beneficial to improving the efficiency of the catalytic reaction.

[0112] 2. X-ray diffraction (XRD) characterization

[0113] X-ray diffraction characterizations were performed on the silicon carbide / nickel foam composite samples, cobalt tetroxide / silicon carbide / nickel foam composite samples, aluminum-cobalt tetroxide / nickel foam composite samples, cobalt tetroxide / nickel foam samples obtained in Comparative Example 1, and the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite samples prepared in Example 1. Figure 3 This is the X-ray diffraction pattern. The five diffraction lines correspond to silicon carbide / nickel foam, cobalt tetroxide / nickel foam, cobalt tetroxide / silicon carbide / nickel foam, aluminum-cobalt tetroxide / nickel foam, and aluminum-cobalt tetroxide / silicon carbide / nickel foam from bottom to top in sequence. It should be noted that the silicon carbide / nickel foam, cobalt tetroxide / nickel foam, cobalt tetroxide / silicon carbide / nickel foam, aluminum-cobalt tetroxide / nickel foam, and aluminum-cobalt tetroxide / silicon carbide / nickel foam samples all contain nickel foam (Ni-foam) components. To simplify Figure 3 the labeling, nickel foam is omitted during the labeling. That is, silicon carbide / nickel foam is labeled as SiC in Figure 3 , cobalt tetroxide / nickel foam is labeled as Co3O4 in Figure 3 , cobalt tetroxide / silicon carbide / nickel foam is labeled as Co3O4 / SiC in Figure 3 , aluminum-cobalt tetroxide / nickel foam is labeled as Co3O4 / Al in Figure 3Labeled as Al-Co3O4, aluminum-cobalt tetroxide / silicon carbide / nickel foam in Figure 3 Labeled as Al-Co3O4 / SiC.

[0114] As Figure 3 shown, the above 5 samples have three peaks (marked with 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.

[0115] For the silicon carbide diffraction lines, there are four peaks (marked with diamonds) at 2θ = 34.2°, 35.7°, 38.2° and 41.5°, belonging to the (101), (102), (103) and (104) planes of silicon carbide [JCPDS29-1131].

[0116] For the cobalt tetroxide diffraction lines, 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.

[0117] It can be seen from the X-ray diffraction characterization that the doping of aluminum does not change the crystal structure of cobalt tetroxide, and thus does not affect the unique electrical and magnetic properties of cobalt tetroxide; at the same time, it can be seen from the left shift of the diffraction peaks that aluminum-cobalt tetroxide conforms to the characteristics of doping, and effective doping of aluminum in cobalt tetroxide is achieved through the hydrothermal reaction.

[0118] 3. Raman spectroscopy characterization

[0119] Perform Raman spectroscopy characterization on the 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 sample prepared in Example 1. Figure 4 For the Raman spectrum diagram, the 4 Raman lines correspond to the cobalt tetroxide / 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 from bottom to top in sequence. It should be noted that the cobalt tetroxide / 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. To simplify Figure 4 the labeling, nickel foam is omitted during labeling, that is, cobalt tetroxide / silicon carbide / nickel foam in Figure 4Labeled as Co3O4 / SiC, cobalt tetroxide / nickel foam in Figure 4 Labeled as Co3O4, aluminum-cobalt tetroxide / nickel foam in Figure 4 Labeled as Al-Co3O4, aluminum-cobalt tetroxide / silicon carbide / nickel foam in Figure 4 Labeled as Al-Co3O4 / SiC.

[0120] As Figure 4 shown, the characteristic peaks of the Raman spectra of the above 4 samples are consistent with the typical spinel cobalt tetroxide structure; however, due to the excessive thinness of silicon carbide, it is not easily detected. Among these characteristic peaks, F 2g (193 cm -1 ) and A 1g (676 cm -1 ) respectively represent the stretching vibrations of the tetrahedral sites (CoO4) and octahedral sites (CoO6) in cobalt tetroxide. In addition, with aluminum doping, the peaks of F 2g and A 1g are significantly red-shifted, which is related to the change of the long-range order of the lattice, indicating that aluminum doping causes more metal vacancies to form in aluminum-cobalt tetroxide.

[0121] 4. X-ray photoelectron spectroscopy (XPS) characterization

[0122] To further elaborate on the surface chemical structure of each sample, X-ray photoelectron spectroscopy analysis was performed on the cobalt tetroxide / nickel foam sample, aluminum-cobalt tetroxide / nickel foam sample, cobalt tetroxide / silicon carbide / nickel foam sample, and the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite sample prepared in Example 1 obtained in Comparative 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, 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. To simplify the labeling of Figure 5(a), Figure 5(b), Figure 5(c), and Figure 5(d), the nickel foam is omitted during labeling, that is, cobalt tetroxide / silicon carbide / nickel foam is labeled as Co3O4 / SiC in Figure 5(a), Figure 5(b), and Figure 5(d), cobalt tetroxide / nickel foam is labeled as Co3O4 in Figure 5(a) and Figure 5(b), aluminum-cobalt tetroxide / nickel foam is labeled as Al-Co3O4 in Figure 5(a), Figure 5(b), and Figure 5(c), and aluminum-cobalt tetroxide / silicon carbide / nickel foam is labeled as Al-Co3O4 / SiC in Figure 5(a), Figure 5(b), Figure 5(c), and Figure 5(d). The Co2p spectra of the above four samples show a mixed valence state of Co 2+and Co 3+ and with two satellite peaks. Based on the relative areas of the fitted peaks, in the samples of cobalt ferrite / nickel foam, aluminum-cobalt ferrite / nickel foam, cobalt ferrite / silicon carbide / nickel foam, and aluminum-cobalt ferrite, the ratio of Co 3+ / Co 2+ is 0.63, 0.69, 0.79, and 0.98, respectively. It can be seen that Al doping tends to replace Co 2+ , resulting in a decrease in the electron state concentration around Co atoms. In aluminum-cobalt ferrite, the reduction of Co 2+ composition shows cation vacancies mainly located around tetrahedral sites. At the same time, the composite of silicon carbide also increases the Co 3+ / Co 2+ ratio. This is consistent with the results of Raman spectroscopy characterization. The O1s spectrum shows that the peak positions at 529.5, 531.1, and 532.2 eV are attributed to O 2- (lattice oxygen), OH - (oxygen vacancy), and H2O (surface adsorbed oxygen), respectively.

[0123] It is not difficult to find that the introduction of silicon carbide greatly reduces the ratio of lattice oxygen / oxygen vacancy, from the original 2.0 to 0.8. For the Ni3p and Al2p spectra, after the introduction of silicon carbide, the obvious peaks at 67.3 eV (Ni-O) and 72.9 eV (Al-O) move to 68.2 eV (Ni-O) and 73.9 eV (Al-O) peaks, indicating a significant increase in the electron state density. For the Si2p spectrum, the three obvious peaks, located at 101.7 eV (Si-C-O), 103.0 eV (Si-O), and 104.6 eV (SiO2) peaks respectively, are not greatly affected by the introduction of Al doping, that is, it does not have a great impact on the characteristics of silicon carbide such as high hardness, high wear resistance, low thermal expansion coefficient, and good chemical stability.

[0124] 5. Catalytic Test

[0125] The catalytic tests were carried out using methods such as linear sweep voltammetry (LSV), Tafel polarization method (Tafel), and cyclic voltammetry (CV) in electrochemical measurement methods to test the oxygen reduction and oxygen evolution of the silicon carbide / nickel foam samples, cobalt tetroxide / silicon carbide / nickel foam samples, aluminum-cobalt tetroxide / nickel foam samples, cobalt tetroxide / nickel foam samples, and the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite material samples obtained in Comparative Example 1. To illustrate the oxygen reduction performance of the samples, a series of electrochemical tests were conducted in a three-electrode system with a 1M KOH electrolyte (a basic potassium hydroxide (KOH) electrolyte with a concentration of 1 mole per liter (mol / L)). The catalytic test results are shown in Figure 6(a) polarization curve; Figure 6(b) overpotential at a current density of 10 mA / cm²; Figure 6(c) Tafel curve; Figure 6(d) linear fitting of the capacitive current density (Δj / 2) and scan rate of the samples at a potential of 0.95 (V vs. RHE). It should be noted that the silicon carbide / nickel foam samples, cobalt tetroxide / nickel foam samples, cobalt tetroxide / silicon carbide / nickel foam samples, aluminum-cobalt tetroxide / nickel foam samples, and aluminum-cobalt tetroxide / silicon carbide / nickel foam samples all contain nickel foam components. To simplify the labeling of Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d), the nickel foam was omitted during labeling. That is, silicon carbide / nickel foam is labeled as SiC in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d); cobalt tetroxide / nickel foam is labeled as Co3O4 in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d); cobalt tetroxide / silicon carbide / nickel foam is labeled as Co3O4 / SiC in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d); aluminum-cobalt tetroxide / nickel foam is labeled as Al-Co3O4 in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d); aluminum-cobalt tetroxide / silicon carbide / nickel foam is labeled as Al-Co3O4 / SiC in Figure 6(a), Figure 6(b), Figure 6(c), and Figure 6(d).

[0126] First, as shown in Figure 6(a), the linear sweep voltammetry (LSV) curve shows that at a current density of 10 mA / cm 2 ², the aluminum-cobalt tetroxide / silicon carbide / nickel foam electrode has the lowest overpotential; at high current densities, the onset potentials of these catalytic electrodes vary greatly. Figure 6(b) provides a more direct performance of each catalyst in each group at a current density of 10 mA / cm 2 ². The overpotential of the aluminum-cobalt tetroxide / silicon carbide / nickel foam electrode is only 268 mV, which is much lower than the overpotentials of cobalt tetroxide / nickel foam (327 mV), aluminum-cobalt tetroxide / nickel foam (328 mV), cobalt tetroxide / silicon carbide / nickel foam (354 mV), and silicon carbide / nickel foam (488 mV).

[0127] This indicates that the aluminum-cobalt tetroxide / silicon carbide / nickel foam electrode has excellent oxygen reduction activity. The Tafel slopes of the samples aluminum-cobalt tetroxide / silicon carbide / nickel foam, aluminum-cobalt tetroxide / nickel foam, cobalt tetroxide / silicon carbide / nickel foam, cobalt tetroxide / nickel foam, and silicon carbide / nickel foam are 65.4, 86.2, 88.9, 104.0, and 106.6 mV dec -1 . The sample aluminum-cobalt tetroxide / silicon carbide / nickel foam has the smallest Tafel slope, indicating its fast reaction kinetics.

[0128] In addition, the cyclic voltammograms at different scan rates in the non-Faradaic region determine the double-layer capacitance of each catalyst. As shown in Fig. 6(d), the C dl values of the samples aluminum-cobalt tetroxide / silicon carbide / nickel foam, aluminum-cobalt tetroxide / nickel foam, cobalt tetroxide / silicon carbide / nickel foam, cobalt tetroxide / nickel foam, and silicon carbide / nickel foam are 46.0, 22.7, 44.9, 45.7, and 3.4 mF / cm 2 , indicating that the C dl value of aluminum-cobalt tetroxide / silicon carbide / nickel foam is larger than those of aluminum-cobalt tetroxide / nickel foam, cobalt tetroxide / silicon carbide / nickel foam, cobalt tetroxide / nickel foam, and silicon carbide, showing a larger active specific surface area; however, the C dl value of silicon carbide is the smallest, showing a larger active specific surface area, which is beneficial to improving the oxygen evolution reaction performance. dl value is the smallest, showing a larger active specific surface area, which is beneficial to improving the oxygen evolution reaction performance.

[0129] 6. Derivation Model

[0130] The Mott-Schottky (M-S) test was carried out on the silicon carbide / nickel foam sample, cobalt tetroxide / nickel foam sample, aluminum-cobalt tetroxide / nickel foam sample obtained in Comparative Example 1, and the aluminum-cobalt tetroxide / silicon carbide / nickel foam composite sample prepared in Example 1. 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 tetroxide / nickel foam sample, Figure 7(c) is the Mott-Schottky curve of the aluminum-cobalt tetroxide / nickel foam sample, and Figure 7(d) is the Mott-Schottky curve of the aluminum-cobalt tetroxide / 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. To simplify the labeling of Figure 7(a), Figure 7(b), Figure 7(c), and Figure 7(d), the nickel foam is omitted during labeling. That is, silicon carbide / nickel foam is labeled as SiC in Figure 7(a), cobalt tetroxide / nickel foam is labeled as Co3O4 in Figure 7(b), aluminum-cobalt tetroxide / nickel foam is labeled as Al-Co3O4 in Figure 7(c), and aluminum-cobalt tetroxide / silicon carbide / nickel foam is labeled as Al-Co3O4 / SiC in Figure 7(d).

[0131] Mott-Schottky analysis is used to test the flat-band voltage and majority carrier concentration of the sample (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 silicon carbide / nickel foam, cobalt tetroxide / nickel foam, aluminum-cobalt tetroxide / nickel foam, and aluminum-cobalt tetroxide / silicon carbide / nickel foam are negative. Therefore, the electrodes silicon carbide / nickel foam, cobalt tetroxide / nickel foam, aluminum-cobalt tetroxide / nickel foam, and aluminum-cobalt tetroxide / silicon carbide / nickel foam are all p-type semiconductors. The flat-band voltages of the silicon carbide / nickel foam, cobalt tetroxide / nickel foam, aluminum-cobalt tetroxide / nickel foam, and aluminum-cobalt tetroxide / silicon carbide / nickel foam electrodes are 1.0, 0.36, 0.46, and 0.45 V respectively. The introduction of silicon carbide does not affect the flat-band voltage. In the aluminum-cobalt tetroxide / silicon carbide / nickel foam electrode, two p-type semiconductors, aluminum-cobalt tetroxide and silicon carbide, form a pp-type Schottky heterojunction, and electrons enter aluminum-cobalt tetroxide 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 metal-semiconductor contact. In this way, two built-in electric fields are formed, which is beneficial to accelerating electron transport.

[0132] It should be noted that the derivation of the model is based on the knowledge of semiconductor physics. Using the Mott-Schottky electrochemical test method, the semiconductor type of each material is tested. 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. When the two are in contact, a Schottky junction (pp junction) is formed. Similarly, for the wide-bandgap semiconductor material silicon carbide in contact with metal nickel, a metal-semiconductor contact is formed. Whether it is a Schottky junction or a metal-semiconductor contact, an internal built-in electric field will be formed, which is beneficial to electron transport.

[0133] In the aluminum-cobalt tetroxide / silicon carbide / nickel foam electrode, the silicon carbide / nickel foam forms a metal-semiconductor contact, constituting the first internal built-in electric field. The aluminum-cobalt tetroxide / silicon carbide forms a Schottky junction, forming the second internal built-in electric field. That is, the aluminum-cobalt tetroxide / silicon carbide / nickel foam accelerates electron transport with a double internal built-in electric field, which is beneficial for oxygen preparation. At the same time, the morphology regulation of the aluminum-cobalt tetroxide / silicon carbide / nickel foam electrode can be changed by changing the concentration of the reactant solution.

[0134] It is easy for those skilled in the art to understand that, on the premise of no conflict, the above-mentioned embodiments can be freely combined and superimposed.

[0135] The above are only the 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 principle of the present application shall be included in the protection scope of the present application. The above is only the preferred implementation manner of the present application. It should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present application, several improvements and variations can be made, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A porous metal matrix composite, characterized in that, The porous metal matrix composite material includes: A foam skeleton carrier, a reinforcement, and an aluminum-cobalt ferrite active nano matrix. The reinforcement covers the foam skeleton carrier, and the aluminum-cobalt ferrite active nano matrix grows on the reinforcement; A metal-semiconductor contact junction is formed between the reinforcement and the foam skeleton carrier to form a first built-in electric field; a Schottky junction is formed between the aluminum-cobalt ferrite active nano matrix and the reinforcement to form a second built-in electric field; The foam skeleton carrier is a foam metal skeleton; the reinforcement is a semiconductor material; the aluminum-cobalt ferrite active nano matrix includes a cobalt ferrite matrix and an active material, and the active material is doped in the cobalt ferrite matrix.

2. The porous metal matrix composite material according to claim 1, wherein The reinforcement is a wide bandgap width material; The aluminum-cobalt ferrite active nano matrix is a narrow bandgap width material.

3. The porous metal matrix composite material according to claim 1, wherein 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 active material is at least one of aluminum and aluminum-based alloys.

4. A method for preparing a porous metal matrix composite, characterized in that, For preparing a porous metal matrix composite material according to any one of claims 1 to 3, the preparation method includes: Pre-treating the foam skeleton carrier; Performing plasma treatment on 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; Preparing a mixed solution by configuring an aluminum source and a cobalt source in a certain proportion; Immersing the foam skeleton carrier deposited with the reinforcement in the mixed solution, and performing a hydrothermal reaction. After the reaction ends, the porous metal matrix composite material is obtained.

5. The preparation method of the porous metal matrix composite material according to claim 4, wherein The pre-treating the foam skeleton carrier includes the steps of: Cutting the foam skeleton carrier, putting the foam skeleton carrier into a container containing deionized water or an organic solvent, putting the container into an ultrasonic cleaner, and cleaning for 15 min to 30 min at a cleaning frequency of 40 kHz to 80 kHz; After the cleaning is completed, taking out the foam skeleton carrier, rinsing it with alcohol, drying it with nitrogen, and then performing low-temperature drying.

6. The preparation method of the porous metal matrix composite material according to claim 4, wherein The performing plasma treatment on the foam skeleton carrier to activate the foam skeleton carrier includes the steps of: Putting the foam skeleton carrier into an oxygen plasma, and performing oxygen plasma atmosphere treatment at a temperature of 300 °C to 700 °C to grow an oxygen-containing compound on the foam skeleton carrier.

7. The preparation method of the porous metal matrix composite material according to claim 4, wherein The magnetron sputtering treatment is carried out on the activated foam skeleton carrier, and a reinforcing body is deposited on the surface of the activated foam skeleton carrier, including the steps: Put the plasma-treated foam skeleton carrier into a magnetron sputtering device, install the target, introduce the protective gas, and carry out 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, and a reinforcing body with a thickness of 80 nm to 120 nm grows on the surface of the activated foam skeleton carrier.

8. The preparation method of a porous metal matrix composite material according to claim 4, wherein The step of preparing a mixed solution by mixing an aluminum source and a cobalt source in a certain proportion includes: Measure 15 mL of deionized water and 15 mL of ethanol, mix and stir evenly, and sequentially add 3 mmol of cobalt nitrate hexahydrate, 15 mmol of urea, and 3.9 mmol of ammonium fluoride, and stir to dissolve to obtain solution A; Add 0.025 g of AlCl3 to solution A and stir to dissolve to obtain a mixed solution B, and the mixed solution B is used as the reaction solution for the hydrothermal reaction.

9. The preparation method of a porous metal matrix composite material according to claim 4, wherein The step of immersing the foam skeleton carrier after depositing the reinforcing body in the mixed solution and carrying out a hydrothermal reaction to obtain the porous metal matrix composite material includes: Transfer the mixed solution to a reaction kettle, put the foam skeleton carrier after depositing the reinforcing body, and take it out after keeping it warm at a temperature of 80 °C to 150 °C for 6 h to 10 h; Wash repeatedly with deionized water and alcohol, and dry to obtain the porous metal matrix composite material.

10. Application of a porous metal matrix composite material, characterized in that, Use a porous metal matrix composite material according to any one of claims 1 to 3 as an electrode for an electrocatalytic reaction.

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