Three-dimensional porous metal nickel / nickel nitride composite material and preparation method and application thereof

Abstract

The invention discloses a three-dimensional porous metal nickel / nickel nitride composite material and a preparation method and application thereof. Relates to the technical field of materials and electrocatalysis. The three-dimensional porous metal nickel / nickel nitride composite material comprises foamed nickel and a nickel and nickel nitride mixed phase loaded on the surface of the foamed nickel, and the generated nickel nitride is of a columnar structure. Nickel nitride with columnar morphology is prepared on a three-dimensional porous foamed nickel substrate by adopting a vacuum plasma nitriding technology, so that the specific surface area of the electrode is further increased, and more active sites are exposed; the nickel nitride directly grows an active layer on the foamed nickel substrate, higher binding force is achieved, meanwhile, after nitrogen atoms are embedded into nickel lattices, the electronic structure of nickel is regulated and controlled, the intrinsic catalytic activity of the material is improved, and meanwhile the prepared three-dimensional porous metal nickel / nickel nitride composite material has better corrosion resistance in an acid / alkaline solution; in addition, the preparation process provided by the invention is simple, low in process cost and suitable for large-scale industrial preparation.

Description

Technical Field

[0001] The present invention belongs to the technical field of materials and electrocatalysis, and in particular relates to a three-dimensional porous metal nickel / nickel nitride composite material and a preparation method and application thereof. Background Art

[0002] In the context of the global energy system transitioning to a low-carbon one, hydrogen energy, as a clean and efficient secondary energy carrier, and its efficient preparation technology are key to promoting the transformation of the energy structure. At present, hydrogen production methods include chemical reforming hydrogen production, industrial by-product hydrogen production and water electrolysis hydrogen production. Among them, water electrolysis hydrogen production uses electricity to drive water to decompose into hydrogen and oxygen. When it is coupled with renewable energy sources such as solar energy and wind energy, it can play the core advantage of zero carbon emissions across the entire chain. However, it is difficult to achieve high energy conversion efficiency by relying solely on the electrochemical process of water reduction and hydrogen evolution. The development of efficient hydrogen evolution catalysts is crucial to improving the performance of water electrolysis. It is known that precious metal platinum-based catalysts are the best performing HER catalysts with low overpotential, high exchange current density and significant reaction stability. They can effectively reduce the water dissociation energy barrier and increase the reaction rate, but their high cost and scarce reserves have seriously restricted large-scale applications. Therefore, the development of efficient, stable and low-cost non-precious metal catalysts has become a research focus in recent years. Summary of the Invention

[0003] The main purpose of the present invention is to provide a three-dimensional porous metal nickel / nickel nitride composite material and its preparation method and application, so as to overcome the shortcomings of the existing technology.

[0004] To achieve the aforementioned object of the invention, the technical solutions adopted by the present invention include:

[0005] A method for preparing a three-dimensional porous metal nickel / nickel nitride composite material comprises applying a bias voltage to a substrate for nitridation treatment using plasma nitridation technology with inert gas and nitrogen as working gas, so that nickel nitride forms a nickel / nickel nitride composite phase on the surface of the substrate; and obtaining the three-dimensional porous metal nickel / nickel nitride composite material.

[0006] Preferably, during the nitridation process, nitrogen atoms are embedded in the nickel lattice to form a chemically bonded interface and a Ni and Ni3N composite phase, which optimizes the free energy of hydrogen adsorption during water electrolysis and improves the efficiency of the hydrogen evolution reaction.

[0007] In some specific embodiments, the flow ratio of the inert gas to the nitrogen gas is 5:75.

[0008] In some specific embodiments, the ion beam current is 0.2A and the ion beam voltage is 2500V.

[0009] In some specific embodiments, the bias voltage is -250V to -750V.

[0010] In some specific embodiments, the purity of the inert gas and nitrogen is greater than 99.9%.

[0011] In some specific embodiments, the inert gas is argon.

[0012] In some specific embodiments, the substrate is nickel foam.

[0013] In some specific embodiments, the porosity of the matrix is ​​75-98%.

[0014] In some specific embodiments, a pre-treatment is further included before the nitriding treatment.

[0015] Preferably, the pretreatment includes placing the substrate in a vacuum plasma nitriding system, raising the system temperature to 500°C, and evacuating the system to 10 -5 Pa.

[0016] In some specific embodiments, the substrate is further subjected to washing and demagnetization treatments before the pre-treatment.

[0017] In some specific embodiments, the washing treatment comprises ultrasonically cleaning the substrate with acetone, hydrochloric acid solution, ethanol and ultrapure water in sequence.

[0018] In some specific embodiments, the demagnetization treatment includes demagnetizing the washed substrate in a demagnetization device.

[0019] As one of the purposes of the invention, the present invention also provides a three-dimensional porous metal nickel / nickel nitride composite material, comprising: a matrix; nickel nitride, loaded on the surface of the nickel foam; the nickel foam and the nickel nitride form a nickel / nickel nitride composite phase; wherein the nickel nitride has a columnar structure.

[0020] Preferably, the substrate comprises nickel foam.

[0021] Preferably, the purity of the nickel foam is ≥99.9%.

[0022] Preferably, the thickness of the nickel foam is 1.6 mm.

[0023] Preferably, the nickel foam has a three-dimensional porous structure.

[0024] Preferably, the content of nitrogen in the nickel nitride is 3-10 wt%.

[0025] As one of the objects of the invention, the present invention also provides the use of the aforementioned three-dimensional porous metal nickel / nickel nitride composite material in the preparation of a hydrogen evolution electrocatalyst.

[0026] The embodiment of the present invention further provides the use of the aforementioned three-dimensional porous metal nickel / nickel nitride composite material in the preparation of a hydrogen evolution electrocatalyst.

[0027] An embodiment of the present invention further provides a three-dimensional porous metal nickel / nickel nitride composite electrode, which at least includes the aforementioned three-dimensional porous metal nickel / nickel nitride composite material.

[0028] The embodiment of the present invention further provides the use of the aforementioned three-dimensional porous metal nickel / nickel nitride composite electrode in an electrocatalytic hydrogen evolution reaction.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) The present invention generates nickel nitride in situ on the surface of nickel foam by plasma nitridation modification, forming a chemical bonding interface, avoiding the problem of traditional supported catalyst shedding, and significantly improving long-term stability. 2 and 100mA cm -2 There was no obvious attenuation of catalytic performance after 24 hours of alternating polarization.

[0031] (2) The present invention uses vacuum plasma technology to bombard the surface of nickel foam with high-energy nitrogen ions to achieve controllable nitridation of nickel foam, avoiding changes in bulk properties. At the same time, no binder or additional chemical reagents are required, reducing the introduction of impurities, and the process has good reproducibility, making it suitable for large-scale production.

[0032] (3) The present invention adopts vacuum plasma nitridation technology to prepare columnar nickel nitride on a three-dimensional porous nickel foam substrate, rather than a nickel nitride layer, which greatly increases the effective reaction area with the solution in the hydrogen evolution reaction.

[0033] (4) The hydrogen evolution reaction of the three-dimensional porous metal nickel / nickel nitride composite material prepared by the present invention is carried out in an alkaline environment. The electrolysis of water in an alkaline environment has obvious advantages. The three-dimensional porous metal nickel / nickel nitride composite material prepared by the present invention can be directly applied to the existing alkaline environment electrolysis water system.

[0034] (5) After the nitrogen atoms in the nickel nitride component of the three-dimensional porous metal nickel / nickel nitride composite material prepared by the present invention are embedded in the nickel lattice, a heterojunction of Ni and Ni3N is formed. The heterojunction interface can cause electron redistribution, and electrons flow from Ni to nickel nitride, thereby adjusting the d-band center of Ni and optimizing the hydrogen adsorption free energy (ΔG H *), improving the intrinsic activity of the catalyst; at the same time, the semiconductor properties of nickel nitride combined with metallic nickel foam can reduce the charge transfer resistance, accelerate the electrochemical reaction, and further reduce the energy consumption of water electrolysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0036] Figure 1 is a scanning electron microscope image of the three-dimensional porous metal nickel / nickel nitride composite electrode prepared in Example 1 of the present invention;

[0037] Figure 2 is a scanning electron microscope image of the three-dimensional porous metal nickel / nickel nitride composite electrode prepared in Example 2 of the present invention;

[0038] Figure 3 : is a chemical composition spectrum diagram of the three-dimensional porous metal nickel / nickel nitride composite electrode prepared in Example 2 of the present invention;

[0039] Figure 4 is a transmission electron microscope image of the three-dimensional porous metal nickel / nickel nitride composite electrode and the nickel foam electrode prepared in Example 2 of the present invention;

[0040] Figure 5 3. Electron diffraction patterns of the three-dimensional porous metal nickel / nickel nitride composite electrode and the nickel foam electrode prepared in Example 2 of the present invention;

[0041] Figure 6 is a chronoamperometric graph of the three-dimensional porous metal nickel / nickel nitride composite electrode prepared in Example 2 of the present invention polarized at different potentials for 24 hours;

[0042] Figure 7 is a scanning electron microscope image of the three-dimensional porous metal nickel / nickel nitride composite electrode prepared in Example 3 of the present invention;

[0043] Figure 8 is a scanning electron microscope image of nickel nitride loaded on nickel foam prepared in Comparative Example 1 of the present invention;

[0044] Figure 9 This is a scanning electron microscope image of nickel nitride-loaded nickel foam prepared in Comparative Example 2 of the present invention;

[0045] Figure 10 It is a linear sweep voltammogram of the catalytic hydrogen evolution reaction of the electrodes prepared in Examples 1 to 3 of the present invention, Comparative Examples 1 and 2, and a pure nickel foam electrode. DETAILED DESCRIPTION

[0046] In view of the shortcomings of the prior art, the inventors of this case, after long-term research and extensive practice, have proposed the technical solution of the present invention. The technical solution of the present invention will be clearly and completely described below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making any creative effort shall fall within the scope of protection of the present invention.

[0047] One aspect of an embodiment of the present invention provides a three-dimensional porous metal nickel / nickel nitride composite material, which includes nickel foam and nickel nitride supported on the surface of the nickel foam, wherein the nickel foam has a three-dimensional porous structure, the nickel nitride has a columnar structure, and the nickel nitride is Ni3N.

[0048] Furthermore, the nickel nitride is loaded on the outer surface of the nickel foam and the surface inside the cavities of the porous structure of the nickel foam.

[0049] Furthermore, the purity of the nickel foam is ≥99.9%.

[0050] Furthermore, the thickness of the nickel foam is 1 to 2 mm.

[0051] Furthermore, the porosity of the nickel foam is 78-99%.

[0052] Furthermore, the content of nitrogen in the nickel nitride is 3-10 wt%.

[0053] Another aspect of the embodiments of the present invention further provides a method for preparing a three-dimensional porous metal nickel / nickel nitride composite material, which comprises:

[0054] Providing nickel foam as a substrate;

[0055] The vacuum plasma nitriding technology is adopted, and an inert gas and nitrogen are used as working gases to carry out nitriding treatment on the surface of the substrate, thereby preparing a three-dimensional porous metal nickel / nickel nitride composite material, wherein the nickel nitride is Ni3N.

[0056] In some more specific embodiments, the preparation method comprises:

[0057] In addition, vacuum plasma nitridation technology is used, with nitrogen as the working gas, to nitride the substrate for 10 hours to obtain a three-dimensional porous metal nickel / nickel nitride composite material, wherein the flow rate of the inert gas is 5 sccm, the flow rate of the nitrogen is 75 sccm, the substrate bias voltage is -250V to -750V, the ion beam current used is 0.15A, and the ion beam voltage is 2500V.

[0058] In some more specific embodiments, the preparation method includes: before depositing the nickel film on the substrate, placing the substrate in a plasma nitridation system, heating the system to 500°C, and evacuating the system to 10 -5 Pa.

[0059] In some more specific embodiments, the preparation method includes: washing and demagnetizing the substrate before depositing the nickel film on the surface of the substrate.

[0060] Furthermore, the washing treatment includes: ultrasonically cleaning the substrate with acetone, hydrochloric acid solution, ethanol and ultrapure water in sequence.

[0061] Furthermore, the demagnetization treatment includes: demagnetizing the washed substrate in a demagnetization device.

[0062] Furthermore, the purity of the inert gas and nitrogen is greater than 99.9%.

[0063] Furthermore, the inert gas includes argon, but is not limited thereto.

[0064] Furthermore, the thickness of the substrate is 1-2 mm.

[0065] Furthermore, the porosity of the nickel foam is 75-98%.

[0066] In some more specific embodiments, the method for preparing the three-dimensional porous metal nickel / nickel nitride composite material may include:

[0067] (1) First, the nickel foam was ultrasonically degreased in acetone for 10 minutes, then acidified in a 10 wt% hydrochloric acid solution, then ultrasonically degreased in alcohol for 10 minutes, and finally ultrasonically degreased in ultrapure water for 10 minutes. After natural drying, the nickel foam was demagnetized on a demagnetizer for 10 seconds.

[0068] (2) The nickel foam prepared in step (1) was suspended on a bracket and placed in a magnetron sputtering composite ion beam thin film deposition device, heated to 500°C, and vacuumed to 10 -5 Pa;

[0069] (3) Open the argon and nitrogen valves, control the argon flow rate to 5-10sccm, the nitrogen flow rate to 75sccm, turn on the ion beam power supply, set the current to 0.2A, control the ion beam voltage to 2500V by the gas flow, change the bias voltage, set the bias voltage to -250~-750V, keep warm for 10h, turn off the bias voltage and ion beam power supply, and cool naturally to room temperature. Nickel nitride can be obtained on the surface of the nickel foam, that is, a three-dimensional porous metal nickel / nickel nitride composite material.

[0070] Another aspect of the embodiments of the present application also provides a three-dimensional porous metal nickel / nickel nitride composite material prepared by the aforementioned method, the nickel foam has a three-dimensional porous structure, the nickel nitride has a columnar structure, and the nickel nitride is Ni3N.

[0071] Another aspect of the embodiments of the present application also provides a use of the aforementioned three-dimensional porous metal nickel / nickel nitride composite material in preparation of a hydrogen evolution electrocatalyst.

[0072] Another aspect of the embodiments of the present application also provides a three-dimensional porous metal nickel / nickel nitride composite electrode comprising at least the aforementioned three-dimensional porous metal nickel / nickel nitride composite material.

[0073] Another aspect of the embodiments of the present application also provides a use of the aforementioned three-dimensional porous metal nickel / nickel nitride composite electrode in an electrocatalytic hydrogen evolution reaction.

[0074] For example, the embodiments of the present application provide a use of the three-dimensional porous metal nickel / nickel nitride electrode in an electrocatalytic hydrogen evolution reaction in an alkaline solution.

[0075] The technical solutions of the present application are described in further detail below in combination with several preferred embodiments and the accompanying drawings. The embodiments are implemented on the premise of the technical solutions of the present application, and detailed implementation manners and specific operation processes are given, but the protection scope of the present application is not limited to the following embodiments.

[0076] The experimental materials used in the following embodiments are commercially available from conventional biochemical reagent companies, unless otherwise specified.

[0077] Embodiment 1

[0078] The embodiments provide a metal nickel / nickel nitride composite material having a three-dimensional porous structure, and the specific preparation steps include:

[0079] (1) The nickel foam is ultrasonically degreased in acetone for 10 min, then acidified in a 10 wt% hydrochloric acid solution, then ultrasonically treated in alcohol for 10 min, and finally ultrasonically treated in ultrapure water for 10 min. After natural air drying, the nickel foam is demagnetized on a demagnetizer for 10 s;

[0080] (2) The nickel foam treated in step (1) is hung on a support and placed in a vacuum plasma nitriding device, heated to 500℃, and vacuumed to 10 -5 Pa;

[0081] (3) Open the argon and nitrogen valves, control the argon flow rate to 5 sccm and the nitrogen flow rate to 75 sccm, turn on the ion beam power supply, set the current to 0.2 A, control the ion beam voltage to 2500 V by the gas flow rate, change the bias voltage, set the bias voltage to -250 V, keep warm for 10 hours, turn off the bias voltage and ion beam power supply, and cool naturally to room temperature. Nickel nitride can be obtained on the surface of the nickel foam, that is, a three-dimensional porous metal nickel / nickel nitride composite material.

[0082] Figure 1 This is an SEM image of the nickel nitride in the three-dimensional porous metal nickel / nickel nitride electrode prepared in this embodiment. It can be seen from the figure that the generated nickel nitride particles begin to grow along the grain boundaries on the surface of the nickel foam to form a heterogeneous structure, that is, the nickel nitride particles are continuously generated along the grain boundaries and finally form a columnar structure.

[0083] Example 2

[0084] This embodiment provides a metal nickel / nickel nitride composite material with a three-dimensional porous structure, and the specific preparation steps include:

[0085] (1) The nickel foam was ultrasonically degreased in acetone for 10 minutes, then acidified in a 10 wt% hydrochloric acid solution, ultrasonically treated in alcohol for 10 minutes, and finally ultrasonically treated in ultrapure water for 10 minutes. After natural drying, the nickel foam was demagnetized on a demagnetizer for 10 seconds.

[0086] (2) The nickel foam treated in step (1) was hung on a bracket and placed in a vacuum plasma nitriding device, heated to 500°C, and vacuumed to 10 -5 Pa;

[0087] (3) Open the argon and nitrogen valves, control the argon flow rate to 5 sccm and the nitrogen flow rate to 75 sccm; turn on the ion beam power supply, set the current to 0.2 A, control the ion beam voltage to 2500 V through the gas flow, adjust the bias voltage to -500 V, keep warm for 10 hours, turn off the bias voltage and ion beam power supply, and cool naturally to room temperature. Nickel nitride can be obtained on the surface of the nickel foam, that is, a three-dimensional porous metal nickel / nickel nitride composite material.

[0088] Figure 2 This is an SEM image of the nickel nitride in the three-dimensional porous metal nickel / nickel nitride electrode prepared in this embodiment. It can be seen from the figure that the nickel nitride obtained on the surface of the nickel foam has a "columnar" morphology rather than a layered structure, which greatly increases the contact area with the solution during the hydrogen evolution reaction.

[0089] Figure 3 : is the chemical composition spectrum of the three-dimensional porous metal nickel / nickel nitride electrode prepared in this embodiment. It can be seen from the spectrum that the mass fraction of nitrogen in the three-dimensional porous metal nickel / nickel nitride electrode is 9.29wt%.

[0090] Figure 4 Figure 3 is a transmission electron microscope image of the three-dimensional porous metal nickel / nitride nickel electrode prepared in this embodiment and a foam nickel electrode, from which it can be seen that the thickness of the nitride nickel in the three-dimensional porous metal nickel / nitride nickel electrode is about 100 nm.

[0091] Figure 5 Figure 4 is a selected electron diffraction image of the three-dimensional porous metal nickel / nitride nickel electrode prepared in this embodiment and a foam nickel electrode, from which it can be seen that the nitride nickel component in the three-dimensional porous metal nickel / nitride nickel electrode is Ni3N.

[0092] Figure 6 Figure 5 is a chronopotentiogram of the three-dimensional porous metal nickel / nitride nickel electrode prepared in this embodiment in a 1 mol / L KOH solution, with a selected current density of 10 mA cm-2 and 100 mA cm-2, and alternating polarization for 24 hours, from which it can be seen that the electrode material prepared in this embodiment has good stability. 2 2

[0093] Embodiment 3

[0094] This embodiment provides a metal nickel / nitride nickel composite material with a three-dimensional porous structure, and the specific preparation steps include:

[0095] (1) ultrasonic degreasing and oil removal of the foam nickel in acetone for 10 min, then acid treatment in a 10 wt% hydrochloric acid solution, then ultrasonic treatment in alcohol for 10 min, and finally ultrasonic treatment in ultrapure water for 10 min, natural air drying, and demagnetization on a demagnetizer device for 10 s;

[0096] (2) suspending the foam nickel treated in step (1) on a support and placing it in a vacuum plasma nitriding device, heating to 500°C, and vacuum pumping to 10 -5 Pa;

[0097] (3) opening the argon and nitrogen valves, controlling the argon flow rate to be 5 sccm and the nitrogen flow rate to be 75 sccm, opening the ion beam power supply, setting the current to be 0.2 A, controlling the ion beam voltage by the gas flow rate to be 2500 V, changing the bias voltage, setting the bias voltage to be -750 V, holding for 10 h, turning off the bias voltage and the ion beam power supply, and naturally cooling to room temperature, to obtain nitride nickel on the surface of the foam nickel, i.e. a three-dimensional porous metal nickel / nitride nickel composite material.

[0098] Figure 7 Figure 6 is an SEM image of the nitride nickel in the three-dimensional porous metal nickel / nitride nickel electrode prepared in this embodiment, from which it can be seen that the nitride nickel obtained on the surface of the foam nickel has a “column” morphology.

[0099] Figure 10 ​​The linear sweep voltammograms of the electrodes prepared in Examples 1 to 3 and the pure nickel foam electrode in 1.0 M KOH solution at a scan rate of 10 mVs- 1 It can be seen that the performance of the electrodes prepared in the three implementation cases is superior to that of pure nickel foam. This is because the nickel atoms sputtered by magnetron sputtering provide more active sites for the catalytic reaction. Secondly, the addition of nitrogen atoms regulates the electron cloud density and the potential distribution of electrons, reducing the Gibbs free energy of H adsorption (ΔG H *), thereby improving the electrocatalytic activity. In addition, as time and energy increase, the surface area of ​​the prepared electrode increases, which increases the contact area with the solution and gradually enhances the electrochemical hydrogen evolution performance.

[0100] Comparative Example 1

[0101] This comparative example provides a method for loading nickel nitride on the surface of nickel foam, specifically comprising:

[0102] (1) The nickel foam was ultrasonically degreased in acetone for 10 min, then acidified in a 10 wt% hydrochloric acid solution, ultrasonically treated in alcohol for 10 min, and finally ultrasonically treated in ultrapure water for 10 min. After natural drying, the nickel foam was demagnetized on a demagnetizer for 10 s.

[0103] (2) The nickel foam treated in step (1) was suspended on a bracket and placed in a magnetron sputtering composite ion beam thin film deposition device, heated to 500°C, and vacuumed to 10 -5 pa;

[0104] (3) Open the nitrogen valve, turn on the ion beam power supply, set the current to 0.2A, use nitrogen as the working gas, control the flow rate to 80sccm, control the ion beam voltage to 2500V through its flow rate, and apply a bias voltage to the substrate at the same time, set the bias voltage to -500V, keep warm for 10 hours, turn off the bias voltage and ion beam power supply, and cool naturally to room temperature. Nickel nitride can be obtained on the surface of the nickel foam.

[0105] Figure 8 This is an SEM image of nickel nitride loaded on nickel foam prepared in Comparative Example 1. It can be seen from the figure that side-by-side particles appear on the surface of the nickel foam. This is because pure nitrogen gas can hardly provide enough energy to make the nickel and nitrogen in the nickel foam combine to form nuclei and grow. A small amount of argon gas can increase the density of the overall plasma and increase the number of free electrons in the system, thereby enhancing the ionization rate of gaseous nitrogen and indirectly increasing the nitrogen ion concentration, which helps to accelerate the nitridation rate and improve the quality of the nitridation layer. At the same time, argon ions have higher kinetic energy during the discharge process, and can remove impurities or tiny oxides remaining on the surface of the workpiece through ion bombardment, further activate the material surface, and create a better interface for subsequent nitrogen atom diffusion.

[0106] Comparative Example 2

[0107] This comparative example provides a three-dimensional porous metal nickel / nickel nitride composite material, which specifically comprises the following steps:

[0108] (1) The nickel foam was ultrasonically degreased in acetone for 10 minutes, then acidified in a 10 wt% hydrochloric acid solution, ultrasonically treated in alcohol for 10 minutes, and finally ultrasonically treated in ultrapure water for 10 minutes. After natural drying, the nickel foam was demagnetized on a demagnetizer for 10 seconds.

[0109] (2) The nickel foam treated in step (1) was hung on a bracket and placed in a vacuum plasma nitriding device, heated to 500°C, and vacuumed to 10 -5 Pa;

[0110] (3) Open the argon and nitrogen valves, control the argon flow rate to 5 sccm and the nitrogen flow rate to 75 sccm, turn on the ion beam power supply, set the current to 0.2 A, control the ion beam voltage to 2500 V by the gas flow rate, do not apply bias, keep warm for 10 hours, turn off the bias and ion beam power supply, and cool naturally to room temperature. Nickel nitride can be obtained on the surface of the nickel foam, that is, a three-dimensional porous metal nickel / nickel nitride composite material.

[0111] Figure 9 This is an SEM image of nickel nitride in the three-dimensional porous metal nickel / nickel nitride electrode prepared in this embodiment. A small amount of nickel nitride particles are generated on the surface of the nickel foam. The particles are scattered and the particles are not connected.

[0112] See Figure 10 , are linear sweep voltammograms of the electrodes prepared in Examples 1-3 and Comparative Examples 1-2, and a pure nickel foam electrode in a 1.0 M KOH solution. It can be seen from the figure that the performance of the metal nickel / nickel nitride electrodes obtained by applying a bias voltage (Examples 1-3) is significantly better than that of the electrode without applying a bias voltage (Comparative Example 2); in Comparative Example 1, pure nitrogen gas is also difficult to provide sufficient energy to enable the nickel and nitrogen in the nickel foam to combine for nucleation and growth, and continuous nickel nitride particles cannot be generated. The performance is quite different from that of the comparative example.

[0113] Comparative Example 3

[0114] This comparative example provides a three-dimensional porous metal nickel / nickel nitride composite material, which specifically comprises the following steps:

[0115] (1) The nickel foam was ultrasonically degreased in acetone for 10 minutes, then acidified in a 10 wt% hydrochloric acid solution, ultrasonically treated in alcohol for 10 minutes, and finally ultrasonically treated in ultrapure water for 10 minutes. After natural drying, the nickel foam was demagnetized on a demagnetizer for 10 seconds.

[0116] (2) The nickel foam treated in step (1) was hung on a bracket and placed in a vacuum plasma nitriding device, heated to 500°C, and vacuumed to 10 -5 Pa;

[0117] (3) Open the argon and nitrogen valves, control the argon flow rate to 10 sccm and the nitrogen flow rate to 70 sccm, turn on the ion beam power supply, set the current to 0.2 A, control the ion beam voltage to 2300 V by the gas flow rate, and set the bias voltage to -500 V. Keep warm for 10 hours, turn off the bias voltage and ion beam power supply, and cool naturally to room temperature. Nickel nitride can be obtained on the surface of the nickel foam, that is, a three-dimensional porous metal nickel / nickel nitride composite material.

[0118] This comparative example is similar to comparative example 1. Only a very small amount of nickel nitride particles are generated on the surface of the nickel foam, which are scattered particles, and no interface connection is achieved between the particles.

[0119] In this comparative example, the flow ratio of nitrogen to argon is 70:10. When the ion beam voltage is actually regulated, the maximum voltage can only reach 2300 V, and cannot reach 2500 V. The composite material finally obtained cannot form a continuous structure.

[0120] In summary, the three-dimensional porous metal nickel / nickel nitride electrode prepared by the present invention uses a three-dimensional porous nickel foam as a matrix, effectively increasing the contact reaction area with the solution, using nitrogen as a nitrogen source, which is abundant in source, and preparing a nickel nitride electrode loaded on the surface of the nickel foam by a vacuum plasma method, wherein the nickel nitride is Ni3N, wherein the nitrogen atoms enter the lattice of the metal nickel to adjust the d orbital electron density, optimize the hydrogen adsorption free energy (ΔG H *), making it easier for hydrogen ions to adsorb onto the surface, promoting the formation and release of hydrogen. Obviously, compared with the preparation of noble metal hydrogen evolution electrodes, the method provided by the present invention has a simpler preparation process and is cheaper, greatly reducing costs and being suitable for large-scale industrial production.

[0121] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments using other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0122] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all respects and are not intended to limit the present invention, the scope of which is defined solely by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the invention as claimed.

[0123] The use of headings and sections in this disclosure is not meant to limit the disclosure; each section may apply to any aspect, embodiment, or feature of the disclosure.

[0124] Throughout this disclosure, where compositions are described as having, comprising, or including particular components, or where processes are described as having, comprising, or including particular process steps, it is contemplated that the compositions taught by the present invention also consist essentially of, or consist of, the recited components, and that the processes taught by the present invention also consist essentially of, or consist of, the recited process steps.

[0125] Should be understood that, the order of each step or the order in which specific action is performed is not very important, as long as the present invention teachings remain operable.In addition, two or more steps or actions can be performed simultaneously.

[0126] Although the present invention has been described with reference to illustrative embodiments, it will be understood by those skilled in the art that various other changes, omissions, and / or additions may be made and that substantial equivalents may be substituted for the elements of the embodiments without departing from the spirit and scope of the present invention. Additionally, many modifications may be made to adapt specific circumstances or materials to the teachings of the present invention without departing from the scope of the present invention. Therefore, it is not intended herein to limit the present invention to the disclosed specific embodiments for carrying out the present invention, but rather to include all embodiments within the scope of the appended claims. Furthermore, unless specifically stated, any use of the terms first, second, etc. does not indicate any order or importance, but rather uses the terms first, second, etc. to distinguish one element from another.

Claims

1. A method for preparing a three-dimensional porous metal nickel / nickel nitride composite material, characterized in that: include By using plasma nitridation technology, inert gas and nitrogen are used as working gases, and bias voltage is applied to the substrate for nitridation treatment, so that nickel nitride is formed on the surface of the substrate, forming a nickel / nickel nitride composite phase; the substrate is three-dimensional porous metal nickel.

2. The method for preparing the three-dimensional porous metal nickel / nickel nitride composite material according to claim 1, characterized in that: The flow ratio of inert gas to nitrogen is 5:75; The ion beam current was 0.15 A and the ion beam voltage was 2500 V; The bias voltage is -250V to -750V.

3. The method for preparing the three-dimensional porous metal nickel / nickel nitride composite material according to claim 1, characterized in that: The purity of the inert gas and nitrogen is greater than 99.9%; and / or, the inert gas is argon; And / or, the substrate is nickel foam; And / or, the porosity of the matrix is ​​75-98%.

4. The method for preparing the three-dimensional porous metal nickel / nickel nitride composite material according to any one of claims 1 to 3, characterized in that: The method further includes pre-treatment before the nitriding treatment; The pretreatment includes placing the substrate in a vacuum plasma nitriding system, raising the system temperature to 500°C, and evacuating the system to 10 -5 Pa.

5. The method for preparing the three-dimensional porous metal nickel / nickel nitride composite material according to claim 4, characterized in that: The substrate is also subjected to washing and demagnetization treatment before the pre-treatment; The washing treatment comprises ultrasonically cleaning the substrate with acetone, hydrochloric acid solution, ethanol and ultrapure water in sequence; The demagnetization treatment includes demagnetizing the washed substrate in a demagnetization device.

6. A three-dimensional porous metal nickel / nickel nitride composite material prepared by the preparation method according to any one of claims 1 to 5, characterized in that: include: matrix; Nickel nitride, supported on the surface of the nickel foam; The nickel foam and the nickel nitride form a nickel / nickel nitride composite phase; Wherein, the nickel nitride is in a column structure.

7. The three-dimensional porous metal nickel / nickel nitride composite material according to claim 6, characterized in that: The substrate includes nickel foam; And / or, the purity of the nickel foam is ≥99.9%; And / or, the thickness of the nickel foam is 1.6 mm; And / or, the nickel foam has a three-dimensional porous structure; And / or, the content of nitrogen in the nickel nitride is 3-10 wt %.

8. Use of a three-dimensional porous metal nickel / nickel nitride composite material prepared by the preparation method according to any one of claims 1 to 5, or a three-dimensional porous metal nickel / nickel nitride composite material according to any one of claims 6 to 7 in preparing a hydrogen evolution electrocatalyst.

9. A three-dimensional porous metal nickel / nickel nitride composite electrode, characterized in that: At least comprising the three-dimensional porous metal nickel / nickel nitride composite material prepared by the preparation method according to any one of claims 1-5, or the three-dimensional porous metal nickel / nickel nitride composite material according to any one of claims 6-7.

10. Use of the three-dimensional porous metal nickel / nickel nitride composite electrode according to claim 9 in an electrocatalytic hydrogen evolution reaction.

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