CN116479464A - Preparation of a ternary metal sulfide membrane electrode and its application in hydrogen production by electrolysis of water - Google Patents

Abstract

The invention belongs to the field of hydrogen production by water electrolysis, and discloses preparation of a ternary metal sulfide membrane electrode and application of hydrogen production by water electrolysis, wherein the preparation method comprises the following steps: (1) preparing a nickel screen; (2) Putting the nickel screen into a mixed solvent in which metal salt and a sulfur source are dissolved, and carrying out hydrothermal reaction after stirring; (3) Collecting a hydrothermal product to obtain a ternary metal sulfide electrode; (4) And simultaneously taking the ternary metal sulfide electrode as a cathode catalytic layer and an anode catalytic layer to be arranged on two sides of the solid electrolyte membrane, and assembling to obtain the membrane electrode. According to the invention, the preparation method of the electrode is improved, the nickel screen is used as a substrate, the ternary metal sulfide is grown on the nickel screen substrate in situ by a one-step hydrothermal method to form the ternary metal sulfide electrode, the corresponding obtained membrane electrode can be directly used for producing hydrogen by an alkaline electrolytic cell, and the electrolytic cell has excellent catalytic activity and stability under ampere-level current density, and is expected to be applied to industrial water electrolysis hydrogen production.

Description

Preparation of a ternary metal sulfide membrane electrode and its application in hydrogen production by electrolysis of water

technical field

The invention belongs to the field of hydrogen production by electrolysis of water, and more specifically relates to the preparation of a ternary metal sulfide film electrode and the application of hydrogen production by electrolysis of water.

Background technique

Hydrogen production by electrolysis of water is one of the effective methods to obtain renewable and clean hydrogen energy. Alkaline electrolyzed water (AWE) technology is a clean and environmentally friendly hydrogen production technology. Compared with traditional alkaline electrolyzed water technology, the diaphragm electrolyzer in AWE technology can achieve high current density (eg: 400mA cm ^-2 ) in a small volume (eg: 9cm ² ), and then efficiently produce high-purity hydrogen. Therefore, the diaphragm electrolyzer provides a reliable and clean hydrogen production route, which truly realizes hydrogen production with zero carbon emissions, which is of great significance to my country's sustainable development route.

The membrane electrode (MEA) is a key component in a diaphragm electrolyzer. Current improvements in water electrolysis efficiency are limited by the slow kinetics of the oxygen evolution reaction (OER). The development of noble metal-based electrode materials (IrO ₂ or RuO ₂ ) is limited by its low storage capacity and cost-effectiveness. Therefore, there is an urgent need to develop non-noble metal electrodes with high performance. It is known in the prior art that transition metal-based electrode materials (transition metal sulfides, nitrides, etc.) have the advantages of abundant reserves and high electrochemical performance. Among them, multi-element metal-based electrode materials can effectively reduce the reaction energy barrier because of the synergy between multi-metal atoms and the advantages of adjustable electronic structure, and realize the output of high current density at low overpotential. However, related materials in the prior art often exhibit activity and stability at milliampere-level current densities (eg, 10-100 mA cm ^-2 ), but the current density does not reach ampere-level current densities (ie, current density ≥ 1A cm ^{-2 ). If an electrode with high activity and high stability at ampere-level current densities (ie, current density ≥ 1Acm -2 )} can be obtained, it will undoubtedly be more conducive to industrial applications.

Contents of the invention

针对现有技术的以上缺陷或改进需求，本发明的目的在于提供一种三元金属硫化物膜电极的制备及电解水制氢应用，其中通过对电极的制备方法进行改进，使用镍网作为基底，通过一步水热法将三元金属硫化物原位生长在镍网基底上形成三元金属硫化物电极，并通过将三元金属硫化物电极同时作为阳极催化层和阴极催化层与固体电解质膜组装成膜电极，得到的膜电极可直接用于碱性电解槽制氢，该电解槽在安培级电流密度(即，电流密度≥1A cm ^-2 )下具备优良的催化活性和稳定性，有望应用于工业电解水制氢；并且该膜电极，尤其适用于强碱电解液的碱性电解槽。 In addition, the preparation method of the present invention has the advantages of simple operation and high cost performance.

In order to achieve the above object, according to one aspect of the present invention, a method for preparing a ternary metal sulfide membrane electrode is provided, which is characterized in that it comprises the following steps:

(1) prepare nickel mesh, and carry out pre-treatment to remove surface impurities to described nickel mesh;

(2) Put the nickel mesh into a mixed solvent in which a metal salt and a sulfur source are dissolved, and transfer it to a reactor for hydrothermal reaction after stirring to obtain a hydrothermal product; wherein, the metal salt is a mixture of metal nickel salt, metal iron salt and metal molybdenum salt; the mixed solvent is a mixed solvent of ethylene glycol and deionized water; the hydrothermal product is a ternary metal sulfide grown on the nickel mesh in situ, and correspondingly, the ternary metal elements in the ternary metal sulfide are nickel element, iron element and molybdenum element;

(3) collecting the hydrothermal product, washing and drying to obtain a ternary metal sulfide electrode;

(4) The ternary metal sulfide electrode is placed on both sides of the solid electrolyte membrane as a cathode catalyst layer and an anode catalyst layer at the same time, and assembled to obtain a membrane electrode.

As a further preference of the present invention, in the step (2), the sulfur source is thiourea; the molar ratio of the metal nickel salt, metal iron salt and metal molybdenum salt in the metal salt is 1:1:1:-4:3:20; the concentration of the metal salt in the mixed solvent is 0.03-0.3mol/L; the molar ratio of the sulfur source to the metal molybdenum salt is 1:4-5:2;

Preferably, the metal nickel salt is nickel nitrate or nickel chloride; the metal iron salt is ferric nitrate or ferric chloride; and the metal molybdenum salt is ammonium molybdate.

As a further preference of the present invention, in the step (2), the hydrothermal temperature of the hydrothermal reaction is 140-180°C, and the holding time is 8-12h;

The mixed solvent is preferably a mixed solvent obtained by mixing ethylene glycol and deionized water at a volume ratio of 2:1-5:1.

As a further preference of the present invention, in the step (1), the wire diameter of the nickel mesh is in the range of 0.15-0.35mm, and the mesh of the nickel mesh is in the range of 0.1-0.48mm;

The pretreatment specifically includes immersing the nickel mesh in hydrochloric acid solution, absolute ethanol and deionized water for ultrasonic cleaning and drying.

As a further preference of the present invention, in the step (4), the solid electrolyte membrane is selected from an anion exchange membrane and a proton exchange membrane.

As a further preference of the present invention, in the step (3), the cleaning is specifically to immerse the hydrothermal product in sequence in absolute ethanol and deionized water for ultrasonic cleaning.

According to another aspect of the present invention, the present invention provides a ternary metal sulfide membrane electrode prepared by the above preparation method.

According to yet another aspect of the present invention, the present invention provides the application of the above-mentioned ternary metal sulfide membrane electrode as a catalytic electrode in hydrogen production in an alkaline electrolyzer.

As a further preference of the present invention, the electrolyte used in the alkaline electrolytic cell for hydrogen production is a strong alkaline electrolyte, preferably a KOH solution with a concentration of 1-7.6 mol/L, more preferably a KOH solution with a concentration of 7.6 mol/L;

The working current density of the alkaline electrolytic cell is ≥1A cm ^-2 .

According to another aspect of the present invention, the present invention provides an alkaline electrolyzer, which is characterized in that the above-mentioned ternary metal sulfide membrane electrode is used as the catalytic electrode.

Through the above technical solutions conceived by the present invention, compared with the prior art, the present invention uses a nickel mesh as a base, prepares a ternary metal sulfide electrode by a one-step hydrothermal method, and uses it as a cathode catalyst and an anode catalyst at the same time, and assembles it with a solid electrolyte membrane to obtain a membrane electrode. Similar to the transition metal-based electrode materials in the prior art, the membrane electrode obtained by the present invention has a high active specific surface area and multi-metal structure. More importantly, the membrane electrode obtained by the present invention has high activity and high stability at an ampere-level current density (i.e., current density ≥ 1A cm ^-2 ), and is especially suitable for alkaline electrolyzers with strong alkaline electrolytes, such as electrocatalytic oxygen evolution under industrial alkaline electrolysis water conditions (such as 7.6M KOH). The corresponding alkaline electrolyzers can effectively solve the current problems. In the field of hydrogen production by electrolysis of water, there are technical problems of poor electrode activity and poor stability under ampere-level current density.

In the prior art, there are also many existing technologies that use nickel foam as the substrate to form transition metal-based electrode materials. They have good activity and stability at milliampere-level current densities (eg, 10-100mA cm ^-2 ), but their stability at ampere-level current densities is not clear. The present invention uses a nickel mesh (the wire diameter of the nickel mesh can be in the range of 0.15-0.35mm, and the mesh hole of the nickel mesh can be in the range of 0.1-0.48mm; the nickel mesh with a diameter of 0.1mm and a wire diameter of 0.15mm as used in the examples below) is used as a base, and the ternary metal sulfide electrode prepared by a one-step hydrothermal method has high activity and high stability at an ampere-level current density. The corresponding alkaline electrolyzer obtained is especially suitable for industrial alkaline electrolysis. Hydrogen production by electrolysis of water under water conditions (eg: 7.6M KOH).

Specifically, the present invention can obtain the following beneficial effects:

(1) The present invention uses nickel mesh and metal salt as raw materials to prepare a ternary metal sulfide electrode by a one-step hydrothermal method, so that it has a heterogeneous interface of crystalline phase/amorphous phase compared with ordinary self-supporting electrodes, so it has a special synergistic effect. This move increases the specific surface area of the self-supporting electrode and facilitates the exposure of active sites. When used as an electrocatalytic oxygen evolution electrode under industrial alkaline water electrolysis conditions (7.6M KOH), the ternary metal sulfide electrode exhibits excellent oxygen evolution activity and high current stability (1A cm ^-2 can work stably for 120h).

(2) The self-supporting electrode based on the in-situ growth of nickel mesh in the present invention can be directly assembled with a solid electrolyte membrane and used as a membrane electrode for an alkaline electrolyzer. This improvement not only avoids the use of binders, but also greatly enhances the electrochemical activity and stability of the catalyst. Taking the powder catalyst in the prior art as an example, the powder catalyst often needs to be mixed with a binder such as Nafion ultrasonically and then coated or sprayed on a conductive substrate. This powder catalyst is easy to drop powder and has poor stability at a high current density (such as: 400mA cm ^-2 ), and it is even worse at an ampere-level current density (such as 1A cm ^-2 ). The method of the present invention is a self-supporting catalyst grown on a conductive substrate in situ, which can be directly used in electrochemical reactions without using a binder.

Description of drawings

FIG. 1 is the XRD spectrum of the ultrasonic powder of the ternary metal sulfide electrode (NiFeMoS/NM) prepared in Example 1.

(a) and (b) in FIG. 2 are scanning electron microscope SEM images of the ternary metal sulfide electrode (NiFeMoS/NM) prepared in Example 1 at different magnifications.

FIG. 3 is a transmission electron microscope TEM image of the ternary metal sulfide electrode (NiFeMoS/NM) prepared in Example 1. FIG.

Fig. 4 is the electrocatalytic oxygen evolution linear voltammetry curves of the ternary metal sulfide electrode (NiFeMoS/NM) prepared in Example 1 and two different electrodes in Comparative Example 1 in 1M KOH.

Fig. 5 is the chronocurrent curve of the ternary metal sulfide electrode (NiFeMoS/NM) prepared in Example 1 in 1M KOH.

Fig. 6 is the electrocatalytic oxygen evolution linear voltammetry curves of the ternary metal sulfide electrode (NiFeMoS/NM) prepared in Example 1 and two different electrodes in Comparative Example 1 in 7.6M KOH.

Fig. 7 is the chronocurrent curve of the ternary metal sulfide electrode (NiFeMoS/NM) prepared in Example 1 at 7.6 MKOH.

Fig. 8 is a schematic diagram of a membrane electrode used for hydrogen production in an alkaline electrolyzer.

9 is a schematic diagram of the water electrolysis performance of two different membrane electrodes prepared in Example 1 (NiFeMoS/NM||NiFeMoS/NM) and Comparative Example 1 in 7.6M KOH.

Figure 10 is the chronovoltage curve of the membrane electrode (NiFeMoS/NM||NiFeMoS/NM) prepared in Example 1 at 7.6M KOH; the voltage waveform shown in the figure, the current density corresponding to the peak voltage is 2A cm ^-2 , and the current density corresponding to the valley voltage is 1A cm ^-2 .

Detailed ways

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not constitute a conflict with each other.

Example 1

This embodiment provides a method for preparing a ternary metal sulfide membrane electrode, the method comprising:

(1) Cut a nickel mesh of a certain size (3*3cm ² , using 100-mesh thickened nickel mesh from Hebei Chaochuang Metal Mesh Co., Ltd., the nickel mesh has an aperture of 0.1mm and a wire diameter of 0.15mm), and put it in hydrochloric acid (0.1M), absolute ethanol, and deionized water to remove impurities (such as oxides on the surface) by ultrasonic.

(2) Weigh 0.365g of nickel nitrate, 0.243g of ferric chloride, 1.976g of ammonium molybdate and 0.2g of thiourea, dissolve them in a mixed solution of 40mL of ethylene glycol and 10mL of deionized water and stir to form solution A.

(3) Take the nickel mesh in the step (1) and immerse it in the solution A obtained in the step (2), transfer it to the reaction kettle after stirring at room temperature. Put the reactor into a high-temperature oven, react at 140° C. for 10 h, and then cool down to room temperature naturally. The hydrothermal product is collected, washed, and dried in a vacuum oven to obtain a ternary metal sulfide electrode (NiFeMoS/NM).

(4) The NiFeMoS/NM electrode is used as the cathode catalytic layer and the anode catalytic layer at the same time, and it is assembled on both sides of the anion exchange membrane to obtain a membrane electrode (as shown in Figure 8, the membrane electrodes are from left to right: nickel mesh and ternary metal sulfide grown on nickel mesh in situ, solid electrolyte membrane, nickel mesh and ternary metal sulfide grown on nickel mesh in situ).

(5) Assemble the membrane electrode and other parts in step (4) into an alkaline electrolyzer (refer to the existing technology related to the alkaline electrolyzer, and assemble the terminal plate, gasket, pole plate and other components with the membrane electrode to obtain an alkaline electrolyzer), and apply a voltage to the electrolyzer at room temperature to 80°C to perform a single-cell test.

Example 2

This embodiment provides a method for preparing a ternary metal sulfide membrane electrode, the method comprising:

(1) Cut a nickel mesh of a certain size (3*3cm ² , using a 100-mesh thickened nickel mesh from Hebei Chaochuang Metal Mesh Co., Ltd.), put it in hydrochloric acid (0.1M), absolute ethanol and deionized water in order to remove impurities by ultrasonic, each ultrasonic time is 20min, and then put it in a vacuum oven at 60°C for 12h.

(2) Weigh 0.365g of nickel nitrate, 0.243g of ferric chloride, 1.976g of ammonium molybdate and 0.2g of thiourea into a mixed solution of 60mL of ethylene glycol and 10mL of deionized water and stir to form solution A.

(3) Take the nickel mesh in the step (1) and immerse it in the solution A obtained in the step (2), transfer it to the reaction kettle after stirring at room temperature. Put the reactor into a high-temperature oven, react at 140° C. for 10 h, and then cool down to room temperature naturally. The hydrothermal product is collected, washed, and dried in a vacuum oven to obtain a ternary metal sulfide electrode (NiFeMoS/NM).

(4) The NiFeMoS/NM electrode is used as the cathode catalyst layer and the anode catalyst layer at the same time, and it is assembled on both sides of the anion exchange membrane to obtain a membrane electrode.

(5) Assemble the membrane electrode and other components in step (4) into an alkaline electrolytic cell, and apply a voltage to the electrolytic cell at room temperature to 80° C. to conduct a single-cell test.

Example 3

This embodiment provides a method for preparing a ternary metal sulfide membrane electrode, the method comprising:

(1) Cut a nickel mesh of a certain size (3*3cm ² , using a 100-mesh thickened nickel mesh from Hebei Chaochuang Metal Mesh Co., Ltd.), put it in hydrochloric acid (0.1M), absolute ethanol and deionized water in order to remove impurities by ultrasonic, each ultrasonic time is 20min, and then put it in a vacuum oven at 60°C for 12h.

(2) Weigh 0.1827g of nickel nitrate, 0.162g of ferric chloride, 0.1976g of ammonium molybdate and 0.1g of thiourea in a mixed solution of 40mL of ethylene glycol and 10mL of deionized water and stir to form solution A.

(3) Take the nickel mesh in the step (1) and immerse it in the solution A obtained in the step (2), transfer it to the reaction kettle after stirring at room temperature. The reaction kettle was put into a high-temperature oven, reacted at 160°C for 10 h, and then cooled to room temperature naturally. The hydrothermal product is collected, washed, and dried in a vacuum oven to obtain a ternary metal sulfide electrode (NiFeMoS/NM).

(4) The NiFeMoS/NM electrode is used as the cathode catalyst layer and the anode catalyst layer at the same time, and it is assembled on both sides of the anion exchange membrane to obtain a membrane electrode.

(5) Assemble the membrane electrode and other components in step (4) into an alkaline electrolytic cell, and apply a voltage to the electrolytic cell at room temperature to 80° C. to conduct a single-cell test.

Comparative example 1

First cut a certain size of nickel mesh (3*3cm ² , using 100-mesh thickened nickel mesh from Hebei Chaochuang Metal Mesh Co., Ltd.), and then place it in hydrochloric acid (0.1M), absolute ethanol and deionized water for ultrasonication, each ultrasonic time is 20min, and then put it in a vacuum oven at 60°C for 12h, and finally obtain a nickel mesh (NW) as a comparison sample.

Application example 1

The ternary metal sulfide electrode (NiFeMoS/NM) obtained in step (3) of Example 1 and the nickel mesh (NW) obtained in Comparative Example 1 were used as industrial electrolytic water oxygen evolution (OER) electrodes, and the activity of the electrodes was evaluated.

The electrochemical performance test was carried out at room temperature using a three-electrode system, and the specific implementation steps were as follows: the ternary metal sulfide electrode (NiFeMoS/NM 1*1cm ² ) obtained in Example 1 was cut. This was used as the working electrode, the carbon rod was used as the counter electrode, and the self-made reversible hydrogen electrode was used as the reference electrode. Firstly, the electrode was swept from the initial potential of 1V to 2V (relative to the reversible hydrogen electrode) for 50 cycles in an oxygen-saturated 1M KOH solution at a sweep rate of 50mV/s to activate the catalyst. Then in the oxygen-saturated 1M KOH solution, scan 1-1.9V at a speed of 10mV/s, which is obtained from the linear scanning voltammetry curve of the supporting electrode (NiFeMoS/NM). The linear voltammetry curve of the electrode obtained in Example 1 corresponds to the dotted line in Figure 4.

Application example 2

The ternary metal sulfide electrode (NiFeMoS/NM) obtained in step (3) of Example 1 and the nickel mesh (NW) obtained in Comparative Example 1 were used as industrial water electrolysis oxygen evolution (OER) electrodes, and the activity of the catalyst was evaluated.

The electrochemical performance test was carried out at room temperature using a three-electrode system, and the specific implementation steps were as follows: the ternary metal sulfide electrode (NiFeMoS/NM 1*1cm ² ) obtained in Example 1 was cut. This was used as the working electrode, the carbon rod was used as the counter electrode, and the self-made reversible hydrogen electrode was used as the reference electrode. Firstly, the electrode was scanned from the initial potential of 1V to 2V (relative to the reversible hydrogen electrode) for 50 cycles at a scan rate of 50mV/s in an oxygen-saturated 7.6M KOH solution to activate the catalyst. Then in an oxygen-saturated 7.6M KOH solution, scan 1-1.9V at a speed of 10mV/s, which is obtained from the linear scanning voltammetry curve of the supporting electrode (NiFeMoS/NM). The linear voltammetry curve of the electrode obtained in Example 1 corresponds to the dotted line in Figure 6.

Application example 3

The ternary metal sulfide electrode (NiFeMoS/NM) obtained in step (3) of Example 1 and the nickel mesh (NW) obtained in Comparative Example 1 were used as a cathode/anode and an anion exchange membrane respectively to assemble a membrane electrode (the schematic diagram of the membrane electrode structure is shown in Figure 8), which was used in an alkaline electrolyzer and the activity of the catalyst was evaluated.

The two-electrode system was used to conduct battery tests at room temperature (RT) and 80°C respectively. The specific implementation steps were as follows: the ternary metal sulfide electrode (NiFeMoS/NM 3*3cm ² ) obtained in Example 1 was used as the anode catalyst layer and the cathode catalyst layer at the same time, and the anode substrate plate, the anode catalyst layer, the anion exchange membrane, the cathode catalyst layer and the cathode substrate layer were stacked in order to form a solid electrolyte water electrolysis membrane electrode structure, and a metal plate was added to obtain a single cell.

The prepared single cells were tested using a FETS-100 battery test system at room temperature and 80°C without external pressure. A single cell test is performed by applying a voltage to the battery.

Result analysis

For the ternary metal sulfide electrodes prepared in the above examples, their morphology and electrochemical performance were mainly characterized by scanning electron microscopy, electrochemical tests under a three-electrode system, and battery performance of an alkaline electrolyzer.

From (a) and (b) in Figure 2, it can be seen that the morphology of the metal active material on the ternary metal sulfide electrode prepared in Example 1 of the present invention is mainly granular, and the granular active material (NiFeMoS) grows uniformly on the surface of the nickel mesh (NM).

It can be seen from Figure 3 that NiFeMoS nanoparticles have abundant crystalline/amorphous heterogeneous interfaces, and the synergistic effect of crystalline and amorphous phases can regulate the electronic structure of catalytic materials and expose more active sites.

It can be seen from Figure 4 that in the alkaline electrolyte (1M KOH), the ternary metal sulfide electrode (NiFeMoS/NM) prepared in Example 1 of the present invention can reach 500mA/cm ² at a lower potential, indicating that the prepared ternary metal sulfide electrode has high electrochemical oxygen evolution activity in the industrial electrolysis water system.

It can be seen from Figure 5 that in alkaline electrolyte (1M KOH), the ternary metal sulfide electrode (NiFeMoS/NM) prepared in Example 1 of the present invention can work stably for 120h at 1A/ ^cm2 , and has high electrochemical stability at high current density.

As can be seen from Figure 6, in the industrial alkaline electrolyte (7.6M KOH), the ternary metal sulfide electrode (NiFeMoS/NM) prepared in Example 1 of the present invention is at 100mA/cm ² , and the corresponding reversible hydrogen electrode potential is less than that of Comparative Example 1, indicating that the prepared ternary metal sulfide electrode has high electrochemical oxygen evolution activity in the industrial electrolysis water system.

It can be seen from Figure 7 that in an industrial alkaline electrolyte (7.6M KOH), the ternary metal sulfide electrode (NiFeMoS/NM) prepared in Example 1 of the present invention can work stably for 120h at 1A/ ^cm2 , and has high electrochemical stability at a high current density.

As can be seen from Figure 8, the alkaline electrolyzer prepared by the present invention is composed of membrane electrodes and other parts.

It can be seen from Figure 9 that in an industrial alkaline electrolyte (7.6M KOH), the NiFeMoS/NM||NiFeMoS/NM alkaline electrolytic cell prepared in Example 1 of the present invention can achieve a current density of 1A cm ^-2 at 80°C with only 1.86V. It shows that the prepared ternary metal sulfide electrode has high electrochemical activity in the industrial electrolysis water system.

It can be seen from Figure 10 that in an industrial alkaline electrolyte (7.6M KOH), the NiFeMoS/NM||NiFeMoS/NM alkaline electrolyzer prepared in Example 1 of the present invention can still work stably at a current density of 1A cm ^{-2 after working at a current density of 2A cm- 2} , indicating that NiFeMoS/NM has high electrochemical stability at an ampere-level current density.

In addition, in the above, except that the temperature is specifically illustrated in FIG. 9 , the other figures are obtained under room temperature conditions.

Above-mentioned embodiment is only example; Except above-mentioned embodiment, adopt different nickel mesh, namely, adopt other nickel mesh of Hebei Chaochuang Metal Mesh Industry Co., Ltd. 30 mesh to 100 mesh (correspondingly, the wire diameter of nickel mesh is within the scope of 0.15-0.35mm, and the mesh hole of nickel mesh is within the scope of 0.1-0.48mm), also can reach similar effect (certainly, embodiment 1 effect is optimal).

It is easy for those skilled in the art to understand that the above descriptions are only preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims (10)

1. The preparation method of the ternary metal sulfide membrane electrode is characterized by comprising the following steps of:

(1) Preparing a nickel screen, and pre-treating the nickel screen to remove surface impurities;

(2) Placing the nickel screen into a mixed solvent in which metal salt and a sulfur source are dissolved, stirring, and transferring the mixed solvent into a reaction kettle for hydrothermal reaction to obtain a hydrothermal product; wherein the metal salt is a mixture of metal nickel salt, metal iron salt and metal molybdenum salt; the mixed solvent is a mixed solvent of glycol and deionized water; the hydrothermal product is ternary metal sulfide grown on a nickel net in situ, and correspondingly, ternary metal elements in the ternary metal sulfide are nickel element, iron element and molybdenum element;

(3) Collecting the hydrothermal product, and cleaning and drying to obtain a ternary metal sulfide electrode;

(4) And the ternary metal sulfide electrode is simultaneously used as a cathode catalytic layer and an anode catalytic layer to be arranged on two sides of the solid electrolyte membrane, and the membrane electrode is obtained by assembly.

2. The method of claim 1, wherein in step (2), the sulfur source is thiourea; the molar ratio of the metal nickel salt to the metal iron salt to the metal molybdenum salt in the metal salt is 1:1:1:4:3:20; the concentration of the metal salt in the mixed solvent is 0.03-0.3mol/L; the molar ratio of the sulfur source to the metal molybdenum salt is 1:4-5:2;

preferably, the metal nickel salt is nickel nitrate or nickel chloride; the metal ferric salt is ferric nitrate or ferric chloride; the metal molybdenum salt is ammonium molybdate.

3. The preparation method according to claim 1, wherein in the step (2), the hydrothermal temperature of the hydrothermal reaction is 140-180 ℃ and the heat preservation time is 8-12h;

the mixed solvent is preferably ethylene glycol and deionized water according to the volume ratio of 2:1-5:1, mixing the obtained mixed solvent.

4. The method according to claim 1, wherein in the step (1), the wire diameter of the nickel mesh is in the range of 0.15 to 0.35mm, and the mesh size of the nickel mesh is in the range of 0.1 to 0.48 mm;

the pretreatment is specifically to immerse nickel screen in hydrochloric acid solution, absolute ethyl alcohol and deionized water in sequence for ultrasonic cleaning and drying.

5. The method according to claim 1, wherein in the step (4), the solid electrolyte membrane is selected from an anion exchange membrane and a proton exchange membrane.

6. The method according to claim 1, wherein in the step (3), the washing is specifically ultrasonic washing by immersing the hydrothermal product in absolute ethanol and deionized water in sequence.

7. A ternary metal sulfide film electrode produced by the production method according to any one of claims 1 to 6.

8. Use of the ternary metal sulfide film electrode according to claim 7 as a catalytic electrode in alkaline cell hydrogen production.

9. The use according to claim 8, wherein the electrolyte used for the hydrogen production in the alkaline electrolyzer is a strong alkaline electrolyte, preferably a KOH solution with a concentration of 1-7.6mol/L, more preferably a KOH solution with a concentration of 7.6 mol/L;

the working current density of the alkaline electrolytic tank is more than or equal to 1A cm ^-2 。

10. An alkaline electrolyzer characterized in that a ternary metal sulfide membrane electrode as claimed in any one of claims 1 to 6 is used as catalytic electrode.