WO2024027108A1

WO2024027108A1 - Electrode having integrated composite structure of matrix and catalyst layer and preparation method therefor

Info

Publication number: WO2024027108A1
Application number: PCT/CN2023/071287
Authority: WO
Inventors: 张存满; 耿振; 金黎明; 吕洪
Original assignee: 同济大学
Priority date: 2022-08-04
Filing date: 2023-01-09
Publication date: 2024-02-08
Also published as: CN115369418A

Abstract

The present invention relates to an electrode having an integrated composite structure of a matrix and a catalyst layer, and a preparation method therefor. The method comprises the following steps: (1) carrying out impurity removal treatment on the surface of a nickel matrix; (2) placing the treated nickel matrix in a nickel precursor aqueous solution for electrodeposition; (3) adding a nickel-based alloy catalyst precursor aqueous solution into the electrodeposited nickel precursor aqueous solution to proceed to electrochemical deposition; (4) placing a composite electrode loaded with a nickel-based alloy catalytic layer having a gradient component structure in an ammonium solution for selective electrochemical etching; and (5) calcining the etched electrode. Compared with the existing technology, the present invention effectively prevents the problem of catalytic layer detachment in composite electrodes during long-term operation, thereby enhancing electrode stability. The matrix has a large specific surface area, ensuring a strong bond with the catalytic layer. In addition, effective control over the microstructure of the catalytic layer may be achieved, effectively increasing the specific surface area of the catalytic layer, and thereby improving the catalytic activity of the composite electrode.

Description

An electrode with an integrated composite structure of a matrix and a catalytic layer and a preparation method thereof

Technical field

The invention relates to the technical field of electrolytic hydrogen production, and in particular to an electrode with an integrated composite structure of a substrate and a catalytic layer and a preparation method thereof.

Background technique

Hydrogen fuel cell vehicles are considered to be an important direction for the future automobile industry due to their advantages such as zero emissions, high efficiency, and diversified fuel sources. They are also an important development means for my country to achieve its dual-carbon strategic goals. Large-scale renewable electrolysis of water to produce hydrogen can effectively solve the problem of "where does hydrogen come from" in the hydrogen fuel cell industry, which is of great strategic significance. Among various electrolysis water hydrogen production technologies, alkaline water electrolysis hydrogen production technology has been commercialized and is currently the mainstream technology for the industrialization of electrolysis water hydrogen production.

Electrodes are the core components of alkaline water electrolyzers and have a significant impact on the kinetic performance and energy efficiency of electrolyzers. At present, most of the electrodes used in alkaline water electrolyzers are spray-coated nickel mesh electrodes, which have problems such as low electrochemical activity and poor hydrogen evolution/oxygen evolution kinetics. By loading high-efficiency catalysts on the surface of the nickel mesh matrix to prepare composite electrodes, it is expected to significantly improve electrode performance. The preparation method of the composite electrode directly affects the composition and microstructure of the supported catalytic layer and the firmness of the bond between the catalytic layer and the substrate, which has an important impact on the performance of the composite electrode.

By increasing the surface roughness of the electrode matrix, the uniformity of catalyst loading can be improved. Chinese invention patents CN114277396A and CN114318398A respectively disclose methods of electrochemically etching nickel substrates in strong acid environments such as sulfuric acid and hydrochloric acid to increase surface roughness. Chinese invention patent CN106498434A discloses a method of chemically etching nickel substrate with weak acid. By controlling the ratio, reaction temperature and reaction time of weak acids such as oxalic acid and citric acid and solution, the surface of the nickel foam substrate is chemically etched to form a Open structures with different defects and specific surface areas.

The catalyst loading method directly affects the microstructure of the catalytic layer and the electrochemically active area of the composite electrode. Chinese invention patent CN111663152A discloses a method of soaking a nickel matrix into a certain concentration of catalyst precursor aqueous solution to support the catalyst through a spontaneous redox reaction. Chinese invention patent CN113265675A discloses a method of spraying high-entropy alloy powder on the surface of an electrode substrate using a spraying process. Chinese invention patent CN113862727A discloses a method of placing a nickel matrix in a catalyst precursor water solvent and loading a NiFe or NiCo alloy catalyst through electrochemical deposition. Chinese invention patent CN114318398A discloses a method of loading NiCoP alloy catalyst on the surface of a nickel matrix through electrochemical deposition. Chinese invention patent CN114293215A discloses a method of hydrothermal reaction combined with high-temperature treatment to support a catalyst. The nickel matrix is placed into a catalyst precursor aqueous solution for hydrothermal reaction, and then the reaction product is placed in a reducing atmosphere tube furnace for high-temperature reduction treatment. , to obtain the catalyst-supported electrode.

Based on the above analysis, through the method involved in the above invention patent, the bonding force between the catalytic layer and the matrix is insufficient, causing the catalytic layer to fall off during the long-term operation of the composite electrode. In addition, the microstructure of the composite electrode after the catalyst is loaded cannot be adjusted, resulting in a certain In the process of increasing the thickness of the catalytic layer, an amorphous pore microstructure will be formed, and closed pores may be formed, which will reduce the kinetic rate of bubbles generated during the hydrogen evolution/oxygen evolution process, thus restricting the electrode performance.

Contents of the invention

The object of the present invention is to provide an electrode with an integrated composite structure of a substrate and a catalytic layer and a preparation method thereof.

The object of the present invention can be achieved through the following technical solutions: a preparation method for an electrode with an integrated composite structure of a substrate and a catalytic layer, including the following steps:

(1) Surface impurity removal treatment of nickel substrate: weak acid treatment to remove surface impurities;

(2) Electrochemical deposition of porous nickel layer: Place the treated nickel matrix in a certain concentration of nickel precursor aqueous solution for electrodeposition, using a two-electrode system, and the treated nickel matrix serves as the cathode;

(3) Electrochemical deposition preparation of the nickel-based alloy catalytic layer: On the basis of step (2), add the nickel-based alloy catalyst precursor aqueous solution to the nickel precursor aqueous solution after electrodeposition to continue electrochemical deposition;

(4) Selective etching of composite electrodes: A composite electrode loaded with a nickel-based alloy catalytic layer with a gradient component structure is placed in a certain concentration of ammonium solution for selective electrochemical etching. A two-electrode system is used, and the composite electrode is used as the anode. ;

(5) Calcining treatment of composite electrode: Calculate the etched electrode.

Preferably, in step (1), the nickel matrix is placed in a weak acid solution and subjected to ultrasonic treatment for 15-60 minutes to remove surface impurities. The weak acid solution includes but is not limited to one of citric acid, oxalic acid, dilute hydrochloric acid, and dilute sulfuric acid. One or more species, with a pH value of 1-4; then rinse the nickel matrix with deionized water to a pH value of 7-8; the nickel matrix is a nickel mesh or nickel foam.

Preferably, in step (2), the initial concentration of Ni ²⁺ in the nickel precursor aqueous solution is 0.1-0.5 mol/L, the current density used for electrochemical deposition is 5-500 mA/cm ² , and the time is 1-20 min. A porous nickel layer is formed in situ on the nickel substrate.

Preferably, in step (3), after the electrodeposited nickel precursor aqueous solution and the added nickel-based alloy catalyst precursor aqueous solution are mixed, the solution contains Ni ²⁺ and M metal ions, and M is not mixed with ammonium ions. The metal elements and M metal ions that undergo coordination complex reactions include but are not limited to one or more of Fe ²⁺ and Mn ²⁺ .

Further preferably, after the electrodeposited nickel precursor aqueous solution and the added nickel-based alloy catalyst precursor aqueous solution are mixed, the initial concentration of Ni ²⁺ in the solution is 0.2-1 mol/L, and the initial concentration of M metal ions is 0.02-0.5 mol/L, the Ni ²⁺ concentration in the initial electrodeposition solution is greater than the M metal ion concentration.

Preferably, in step (3), the current density used for electrochemical deposition is 1-500 mA/cm ² and the time is 1-60 min.

Preferably, in step (3), during the electrochemical deposition process, the catalyst precursor aqueous solution containing M metal ions but not Ni ²⁺ is continuously added, and the M metal ion concentration is 0.02-0.5 mol/L, so that during the entire electrodeposition During the process, the relative concentration of Ni ²⁺ and the relative concentration of M metal ions showed a continuous gradient change. The relative concentration of Ni ²⁺ gradually decreased, and the relative concentration of M metal ions gradually increased. Finally, a nickel base with a gradient component structure (continuous change of components) was formed. Alloy catalytic layer.

Preferably, in step (4), the concentration of the ammonium solution is 0.1-2mol/L, and the ammonium compounds used in preparing the ammonium solution include but are not limited to ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium nitrate, ammonium carbonate, and acetic acid. One or more of ammonium and ammonium oxalate; the current density used for electrochemical etching is 5-100mA/cm ² and the time is 5-60min.

Preferably, after the composite electrode is selectively etched, the composite electrode is cleaned with deionized water, dried, and then placed in a protective atmosphere for calcination treatment. The calcination temperature is 200-600°C and the calcination time is 0.5-4h. Finally, An electrode with an integrated composite structure of the substrate and the catalytic layer is obtained.

An electrode with an integrated composite structure of a matrix and a catalytic layer is prepared by using the above preparation method.

An application of an electrode with an integrated composite structure of a substrate and a catalytic layer, where the electrode is used for alkaline electrolysis to produce hydrogen.

Aiming at the problems of insufficient bonding force between the supported catalytic layer and the matrix and difficulty in regulating the microstructure of the composite electrode after the catalyst is loaded, the present invention proposes a nickel-based alloy composite electrode with an integrated composite structure of the matrix and the catalytic layer and a preparation method thereof. First, the nickel matrix is placed in a weak acid solution for ultrasonic pretreatment to remove surface impurities; then, the nickel matrix is used as a cathode and placed in a nickel precursor aqueous solution to deposit metallic nickel under electrochemical conditions. Through the hydrogen evolution reaction accompanying this process The generated hydrogen creates pores in the deposited nickel layer, forming a porous nickel layer in situ on the nickel collective; then, the nickel-based alloy catalyst precursor aqueous solution is added to the electrodeposition solution, and the nickel-based alloy catalyst is deposited under electrochemical conditions. The concentration of the catalyst precursor components is continuously adjusted to form a nickel-based alloy catalytic layer with a gradient structure in situ on the porous nickel layer; then, the composite electrode supporting the catalytic layer is placed in an ammonium solution (ammonium ion aqueous solution) for selectivity Electrochemical etching uses the coordination complexation reaction between nickel and ammonium ions and combines with the electrochemical environment to dissolve part of the nickel in the ammonium solution to increase the specific surface area of the catalytic layer and form a large number of open pore structures, and finally make A nickel-based alloy composite electrode with an integrated composite structure of the matrix and the catalytic layer is obtained. The composite electrode prepared by the present invention uses the "additive manufacturing" strategy to grow porous nickel in situ on the nickel matrix to increase the specific surface area of the nickel matrix, and uses the porous nickel layer as an interface layer to catalyze the in-situ grown catalytic layer It is closely combined with the substrate and has the structural characteristics of integrating the substrate and the catalytic layer. The surface of the nickel substrate is evenly covered with a nickel-based alloy catalytic layer with continuously changing components. From the side close to the substrate to the side of the electrode surface, the alloy composition of the catalytic layer The nickel content gradually decreases while the content of other alloy components gradually increases, and the catalytic layer has a high specific surface area and a large number of open pore structures. The prepared composite electrode exhibits excellent catalytic activity and stability.

Compared with the prior art, the present invention has the following advantages:

1. The present invention adopts the "additive manufacturing" strategy to electrochemically deposit porous nickel in situ on the nickel matrix to increase the specific surface area of the nickel matrix. The porous nickel layer is used as a transition interface layer to electrochemically deposit in situ growth. The catalytic layer and the substrate are closely combined to form an integrated composite structure of the substrate and the catalytic layer, which avoids loading the catalytic layer directly onto the carrier, effectively prevents the problem of the catalytic layer falling off during long-term operation of the composite electrode, and improves the stability of the electrode. It has a large specific surface area and is firmly combined with the catalytic layer. In addition, it can effectively control the microstructure of the catalytic layer, effectively increasing the specific surface area of the catalytic layer and improving the catalytic activity of the composite electrode;

2. The composite electrode catalytic layer of the present invention has a large specific surface area, high catalytic activity, and the etching method is gentle and effective. The method of the present invention can effectively control the microstructure of the composite electrode after the catalyst is loaded, and utilizes the coordination of metal nickel and ammonium ions. Complexation reaction, selective etching of metallic nickel in the catalytic layer under electrochemical conditions, thereby increasing the specific surface area of the catalytic layer and forming a large number of open pore structures to improve the escape power of bubbles generated during the hydrogen evolution/oxygen evolution process learning rate, thereby improving electrode performance and showing excellent catalytic activity and bubble escape kinetics;

3. Compared with the existing acid etching method, the ammonium liquid electrochemical etching method involved in the present invention is gentle and effective, and does not produce dangerous products such as hydrogen;

4. The method of the present invention is simple and easy to implement, safe to operate, and easy to industrialize. The nickel-based alloy composite electrode prepared by the method of the present invention has excellent hydrogen evolution/oxygen evolution catalytic activity and stability in alkaline water electrolysis for hydrogen production.

Description of the drawings

Figure 1 is a process flow diagram of the present invention;

Figure 2 shows the morphology of the nickel matrix;

Figure 3 is a surface morphology diagram of the composite electrode prepared in Example 1;

Figure 4 is a linear scan curve of the oxygen evolution reaction of the composite electrode and nickel mesh prepared in Example 1. Test conditions: two-electrode system, the composite electrode or nickel mesh is the working electrode, the platinum sheet is the counter electrode, and the 30wt% concentration KOH aqueous solution is Electrolyte solution, scan rate is 5mV/s;

Figure 5 is a linear scan curve of the hydrogen evolution reaction of the composite electrode and nickel mesh prepared in Example 1. Test conditions: two-electrode system, the composite electrode or nickel mesh is the working electrode, the platinum sheet is the counter electrode, and the 30wt% concentration KOH aqueous solution is the electrolyte. Solution, scan rate is 5mV/s;

Figure 6 is a comparison chart of the oxygen evolution reaction chronopotentiometric curve of the composite electrode prepared in Example 1 and the nickel mesh as anode at a current density of 500mA/ ^cm2 . The electrolysis time is 200 hours;

Figure 7 is a comparison chart of the hydrogen evolution and oxygen evolution potentials of the composite electrode and nickel mesh prepared in Examples 1-5 respectively at a current density of 500mA/ ^cm2 . Test conditions: two-electrode system, the composite electrode or nickel mesh is the working electrode, platinum The chip is the counter electrode, the 30wt% concentration KOH aqueous solution is the electrolyte solution, and the scanning rate is 5mV/s.

Detailed ways

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The following examples are implemented on the premise of the technical solution of the present invention and provide detailed implementation modes and specific operating processes. However, the protection scope of the present invention is not limited to the following examples.

A method for preparing an electrode with an integrated composite structure of a matrix and a catalytic layer. The specific method steps include:

(1) Surface impurity removal treatment of nickel substrate

The nickel matrix is placed in a weak acid solution and subjected to ultrasonic treatment for 15-60 minutes to remove surface impurities. The weak acid solution includes but is not limited to one or more of citric acid, oxalic acid, dilute hydrochloric acid, and dilute sulfuric acid, with a pH value of 1 -4; then rinse the nickel matrix with deionized water to bring the pH to 7-8. The nickel matrix is nickel mesh or nickel foam.

(2) Electrochemical deposition of porous nickel layer

The treated nickel matrix is placed in a certain concentration of nickel precursor aqueous solution for electrodeposition. A two-electrode system is used, and the treated nickel matrix serves as the cathode. The initial concentration of Ni ²⁺ in the nickel precursor aqueous solution is 0.1-0.5mol/L, the current density used in the electrochemical deposition is 5-500mA/cm ² , the time is 1-20min, and porous holes are formed in situ on the nickel matrix. Nickel layer.

(3) Electrochemical deposition preparation of nickel-based alloy catalytic layer

On the basis of (2), the nickel-based alloy catalyst precursor aqueous solution is added to the nickel precursor aqueous solution after electrodeposition to continue electrochemical deposition. After the electrodeposited nickel precursor aqueous solution is mixed with the added nickel-based alloy catalyst precursor aqueous solution, the solution contains Ni ²⁺ and M metal ions, and M is a metal element that does not undergo coordination and complexation reactions with ammonium ions. , M metal ions include but are not limited to one or more of Fe ²⁺ and Mn ²⁺ , where the initial concentration of Ni ²⁺ is 0.2-1mol/L, and the initial concentration of M metal ions is 0.02-0.5mol/L. The Ni ²⁺ concentration in the electrodeposition solution is greater than the M metal ion concentration. The current density used for electrochemical deposition is 1-500mA/cm ² and the time is 1-60min. During the electrochemical deposition process, the aqueous catalyst precursor solution with M metal ions but not Ni ²⁺ is continuously added, and the M metal ion concentration is 0.02-0.5 mol/L, so that the Ni ²⁺ concentration and M The metal ion concentration shows a continuous gradient change, the Ni ²⁺ concentration gradually decreases, and the M metal ion concentration gradually increases, eventually forming a nickel-based alloy catalytic layer with continuously changing components.

(4) Selective etching of composite electrodes

A composite electrode carrying a nickel-based alloy catalytic layer with a gradient component structure is placed in a certain concentration of ammonium solution (ammonium ion aqueous solution) for selective electrochemical etching. A two-electrode system is used, with the composite electrode serving as the anode. The concentration of the ammonium liquid is 0.1-2mol/L. The ammonium compound used in preparing the ammonium liquid includes but is not limited to one of ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium nitrate, ammonium carbonate, ammonium acetate, ammonium oxalate or Several kinds. The current density used for electrochemical etching is 5-100mA/cm ² and the time is 5-60min.

(5) Calcination treatment of composite electrode

The composite electrode after the above treatment is washed with deionized water, dried, and then placed in a protective atmosphere for sintering treatment. The calcination temperature is 200-600°C and the calcination time is 0.5-4h. Finally, a nickel-based alloy composite electrode with an integrated composite structure of the matrix and the catalytic layer is obtained.

The following are specific examples:

Example 1

The nickel mesh was placed in a hydrochloric acid solution with a pH value of 2 for 30 minutes to remove surface impurities; the treated nickel mesh was placed in a 0.3 mol/L nickel chloride aqueous solution for electrodeposition, using a two-electrode system, nickel The net is used as the cathode, and the current density used for electrochemical deposition is 300mA/cm ² and the time is 10 minutes. A porous nickel layer is formed in situ on the nickel substrate; then, nickel chloride and chloride are added to the nickel precursor aqueous solution after electrodeposition. From the ferrous aqueous solution to a nickel chloride concentration of 0.5mol/L and a ferrous chloride concentration of 0.3mol/L, continue electrochemical deposition. The current density used for electrochemical deposition is 300mA/cm ² and the time is 30min. In the electrochemical deposition During the deposition process, 0.3 mol/L ferrous chloride aqueous solution is continuously added, so that in the nickel-iron catalytic layer formed, the relative content of nickel gradually decreases and the relative content of iron gradually increases, finally forming a nickel-iron catalytic layer with continuously changing components; then The composite electrode supporting the nickel-iron catalytic layer is placed in a 1mol/L ammonium chloride aqueous solution for selective electrochemical etching to dissolve part of the nickel component in the catalytic layer. The current density used for electrochemical etching is 50mA/cm ² and the time is 30 minutes; the composite electrode after the above treatment is cleaned with deionized water, dried, and then calcined in a nitrogen atmosphere. The calcining temperature is 400°C and the calcining time is 2 hours. Finally, a composite electrode with an integrated matrix and a catalytic layer is obtained. Structure of nickel-iron alloy composite electrode.

Figure 2 shows the morphology of the nickel mesh matrix, and Figure 3 shows the morphology of the nickel-iron alloy composite electrode prepared in Example 1. It can be seen that the surface of the nickel mesh matrix is evenly covered with the nickel-iron alloy catalyst, and the surface of the catalytic layer is rough and has a large number of Open holes. In terms of performance, as shown in Figure 4, the oxygen evolution overpotential of the nickel-iron alloy composite electrode prepared in Example 1 at a current density of 500mA/ ^cm2 is lower than that of the traditional nickel mesh; as shown in Figure 5, the nickel-iron alloy composite electrode prepared in Example 1 The hydrogen evolution overpotential of the nickel-iron alloy composite electrode at a current density of 500mA/ ^cm2 is lower than that of the traditional nickel mesh; as shown in Figure 6, the performance of the nickel-iron alloy composite electrode prepared in Example 1 as an anode at a current density of 500mA/ ^cm2 The stability is significantly better than traditional nickel mesh.

Figure 7 shows the comparison of hydrogen evolution and oxygen evolution potentials of the nickel-based alloy composite electrodes and nickel mesh prepared in Examples 1-5 respectively at a current density of 500mA/ ^cm2 . It can be seen that the performance of the prepared nickel-based alloy composite electrodes Both are better than nickel mesh.

Example 2

In this embodiment, during the in-situ formation of the porous nickel layer on the nickel substrate, the nickel precursor aqueous solution used was 0.5 mol/L nickel sulfate, the current density used was 5 mA/cm ² , and the time was 20 minutes; then, the electrolyte During the process of depositing the catalyst, the initial catalyst precursor aqueous solution was 1 mol/L nickel sulfate and 0.5 mol/L ferrous sulfate aqueous solution. The current density used for electrochemical deposition was 1 mA/cm ² and the time was 60 min. During the electrochemical deposition process , continuously add 0.5mol/L ferrous sulfate aqueous solution; then place the composite electrode supporting the nickel-iron catalytic layer in a 2mol/L ammonium nitrate aqueous solution for selective electrochemical etching, and the current density used for electrochemical etching is 5mA/cm ² , the time is 60 minutes; then the calcination treatment is performed under a nitrogen atmosphere, the calcination temperature is 200°C, the calcination time is 4 hours, and finally a nickel-iron alloy composite electrode with an integrated composite structure of the matrix and the catalytic layer is obtained. The rest is the same as in Example 1.

Example 3

In this embodiment, during the in-situ formation of the porous nickel layer on the nickel substrate, the nickel precursor aqueous solution used was 0.1 mol/L nickel nitrate, the current density used was 500 mA/cm ² , and the time was 1 min; and then the electrolyte During the process of depositing the catalyst, the initial catalyst precursor aqueous solution is 0.2mol/L nickel nitrate and 0.02mol/L manganese nitrate aqueous solution. The current density used for electrochemical deposition is 500mA/cm ² and the time is 1 minute. During the electrochemical deposition process , continuously add 0.02mol/L manganese nitrate aqueous solution; then place the composite electrode supporting the nickel-manganese catalytic layer in 0.1mol/L ammonium nitrate aqueous solution for selective electrochemical etching. The current density used for electrochemical etching is 100mA/cm ² , the time is 5 minutes; then calcining is performed under an argon atmosphere, the calcining temperature is 600°C, the calcining time is 0.5h, and finally a nickel-manganese alloy composite electrode with an integrated composite structure of the matrix and the catalytic layer is obtained. The rest is the same as in the Example 1 is the same.

Example 4

In this embodiment, during the in-situ formation of the porous nickel layer on the nickel substrate, the nickel precursor aqueous solution used was 0.2 mol/L nickel nitrate, the current density used was 200 mA/cm ² , and the time was 15 min; and then the electrolyte In the process of depositing the catalyst, the initial catalyst precursor aqueous solution is 0.8mol/L nickel nitrate, 0.3mol/L ferrous nitrate aqueous solution, and 0.2mol/L manganese nitrate aqueous solution. The current density used for electrochemical deposition is 200mA/cm ² , and the time for 60 minutes. During the electrochemical deposition process, 0.3 mol/L ferrous nitrate aqueous solution and 0.2 mol/L manganese nitrate aqueous solution were continuously added; then the composite electrode loaded with the nickel iron manganese catalytic layer was placed in a 1.5 mol/L ammonium oxalate aqueous solution. Selective electrochemical etching is carried out. The current density used for electrochemical etching is 80mA/cm ² and the time is 40 minutes. Then the calcination treatment is carried out in an argon atmosphere. The calcination temperature is 500°C and the calcination time is 4h. Finally, a matrix is obtained. A nickel-iron-manganese ternary alloy composite electrode with a composite structure integrated with the catalytic layer is the same as in Example 1.

Example 5

In this embodiment, during the in-situ formation of the porous nickel layer on the nickel substrate, the nickel precursor aqueous solution used was 0.1 mol/L nickel chloride, the current density used was 100 mA/cm ² , and the time was 20 minutes; then, the following In the process of electrodepositing the catalyst, the initial catalyst precursor aqueous solution is 0.5mol/L nickel chloride, 0.3mol/L manganese chloride, and 0.1mol/L ferrous chloride aqueous solution. The current density used for electrochemical deposition is 100mA/ cm ² , time is 30min. During the electrochemical deposition process, 0.3mol/L manganese chloride aqueous solution and 0.1mol/L ferrous chloride aqueous solution are continuously added; then the composite electrode supporting the nickel-manganese-ferrocatalytic layer is placed in a 1mol/L Selective electrochemical etching is carried out in L ammonium chloride aqueous solution. The current density used for electrochemical etching is 60mA/cm ² and the time is 50 minutes. Then, calcination treatment is performed under a helium atmosphere. The calcination temperature is 600°C and the calcination time is After 4 hours, a nickel-manganese-iron ternary alloy composite electrode with an integrated composite structure of the matrix and the catalytic layer was finally obtained, and the rest was the same as in Example 1.

The above description of the embodiments is to facilitate those of ordinary skill in the technical field to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without inventive efforts. Therefore, the present invention is not limited to the above embodiments. Based on the disclosure of the present invention, improvements and modifications made by those skilled in the art without departing from the scope of the present invention should be within the protection scope of the present invention.

Claims

A method for preparing an electrode with an integrated composite structure of a matrix and a catalytic layer, which is characterized by including the following steps:

(1) Surface impurity removal treatment of nickel substrate: weak acid treatment to remove surface impurities;

(2) Electrochemical deposition of porous nickel layer: Place the treated nickel matrix in a nickel precursor aqueous solution for electrodeposition, using a two-electrode system, and the treated nickel matrix serves as the cathode;

(3) Electrochemical deposition preparation of the nickel-based alloy catalytic layer: On the basis of step (2), add the nickel-based alloy catalyst precursor aqueous solution to the nickel precursor aqueous solution after electrodeposition to continue electrochemical deposition;

(4) Selective etching of composite electrodes: A composite electrode loaded with a nickel-based alloy catalytic layer with a gradient component structure is placed in an ammonium solution for selective electrochemical etching, using a two-electrode system with the composite electrode as the anode;

(5) Calcining treatment of composite electrode: Calculate the etched electrode.
The method for preparing an electrode with an integrated composite structure of a matrix and a catalytic layer according to claim 1, characterized in that in step (1), the nickel matrix is placed in a weak acid solution and subjected to ultrasonic treatment for 15-60 minutes to remove the surface Impurities, the weak acid solution includes but is not limited to one or more of citric acid, oxalic acid, dilute hydrochloric acid, and dilute sulfuric acid, with a pH value of 1-4; then rinse the nickel matrix with deionized water, and the pH value reaches 7 -8; The nickel matrix is nickel mesh or nickel foam.
The method for preparing an electrode with an integrated composite structure of a matrix and a catalytic layer according to claim 1, characterized in that in step (2), the initial concentration of Ni 2+ in the nickel precursor aqueous solution is 0.1-0.5 mol/ L, the current density used for electrochemical deposition is 5-500mA/cm 2 , the time is 1-20min, and a porous nickel layer is formed in situ on the nickel substrate.
The method for preparing an electrode with an integrated composite structure of a matrix and a catalytic layer according to claim 1, characterized in that in step (3), the electrodeposited nickel precursor aqueous solution and the added nickel-based alloy catalyst precursor After the bulk aqueous solution is mixed, the solution contains Ni 2+ and M metal ions. M is a metal element that does not undergo coordination and complexation reactions with ammonium ions. The M metal ions include but are not limited to one of Fe 2+ and Mn 2+ species or several species.
The method for preparing an electrode with an integrated composite structure of a matrix and a catalytic layer according to claim 4, characterized in that after the electrodeposited nickel precursor aqueous solution and the added nickel-based alloy catalyst precursor aqueous solution are mixed, the solution The initial concentration of Ni 2+ in the solution is 0.2-1 mol/L, and the initial concentration of M metal ions is 0.02-0.5 mol/L. The Ni 2+ concentration in the initial electrodeposition solution is greater than the M metal ion concentration.
The method for preparing an electrode with an integrated composite structure of a substrate and a catalytic layer according to claim 1, characterized in that in step (3), the current density used for electrochemical deposition is 1-500mA/cm 2 and the time is 1-500mA/cm 2 . 60 minutes.
The method for preparing an electrode with an integrated composite structure of a matrix and a catalytic layer according to claim 1, characterized in that in step (3), during the electrochemical deposition process, metal ions having M but not Ni 2+ are continuously added The catalyst precursor aqueous solution has a M metal ion concentration of 0.02-0.5 mol/L, so that the relative concentration of Ni 2+ and the relative concentration of M metal ions present a continuous gradient change during the entire electrodeposition process, and the relative concentration of Ni 2+ gradually decreases, M The relative concentration of metal ions gradually increases, eventually forming a nickel-based alloy catalytic layer with a gradient component structure.
The method for preparing an electrode with an integrated composite structure of a matrix and a catalytic layer according to claim 1, characterized in that in step (4), the ammonium liquid concentration is 0.1-2 mol/L, and the ammonium liquid used to prepare the ammonium liquid is Ammonium compounds include but are not limited to one or more of ammonium chloride, ammonium sulfate, ammonium phosphate, ammonium nitrate, ammonium carbonate, ammonium acetate, and ammonium oxalate; the current density used for electrochemical etching is 5-100mA/cm 2 , The time is 5-60min.
The method for preparing an electrode with an integrated composite structure of a matrix and a catalytic layer according to claim 1, characterized in that after the composite electrode is selectively etched, the composite electrode is cleaned with deionized water, dried, and then placed in a protective The calcination treatment is carried out in a neutral atmosphere, the calcination temperature is 200-600°C, the calcination time is 0.5-4h, and finally an electrode with an integrated composite structure of the matrix and the catalytic layer is obtained.
An electrode with an integrated composite structure of a substrate and a catalytic layer, characterized in that it is produced by the preparation method according to any one of claims 1 to 9.