A nickel-based self-supporting hydrogen evolution electrode and its preparation method and application

Abstract

The invention belongs to the field of electrocatalytic full water splitting technology, discloses a nickel-based self-supporting hydrogen evolution electrode and its preparation method and application, including dissolving nickel chloride hexahydrate and terephthalic acid in N, N-dimethylformamide to control the concentration of nickel chloride hexahydrate to 0.1-0.15mol / L, the concentration of terephthalic acid to 0.1-0.15mol / L, stirring evenly, ultrasonic treatment to prepare an electrolyte; the pretreated nickel foam is immersed in the electrolyte as a working electrode, a platinum mesh is used as a counter electrode, and a reference electrode adopts an Ag / AgCl electrode, applying a 10-20mA current deposition 1.5-2.5h, and after electrodeposition, cleaning and drying to obtain a nickel-based self-supporting hydrogen evolution electrode. The nickel-based self-supporting catalytic material prepared by the present invention more fully exposes active sites, has higher catalytic performance, has good application prospects in the field of electrocatalytic material technology, and is expected to improve energy and environmental problems.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalytic water splitting, and in particular relates to a nickel-based self-supporting hydrogen evolution electrode and a preparation method and application thereof. Background Art

[0002] Electrocatalytic water splitting is one of the current technologies for efficiently producing "green hydrogen". The hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) are the two half reactions of water electrolysis, and they are both crucial to the overall efficiency of water electrolysis. However, the large overpotentials and slow kinetics of HER and OER seriously hinder the practical application of water splitting. An ideal hydrogen evolution electrode must meet the following requirements: first, it needs to be highly active and able to achieve hydrogen evolution at a high current density under a small overpotential; second, it must have good stability. The catalysts used in the currently developed highly active hydrogen evolution electrodes are mainly composed of precious metals such as platinum, palladium, and iridium. Their high price and poor stability limit their application and popularity in water electrolysis. Self-supporting electrodes are a type of excellent electrode in which the catalyst is directly deposited on a conductive substrate. However, the hydrogen evolution current density exhibited by many self-supporting electrodes at low overpotentials is still low (for example, the current density is generally less than 1000 mA cm at an overpotential of less than 0.25V). -2 ), the preparation process is relatively complicated and it is difficult to meet the requirements of industrial applications of electrolyzed water. For example, a supported nickel-based composite hydrogen evolution catalyst and its preparation method and application are disclosed in a Chinese patent document (application number 202011504106.7), the steps of which include: first pre-treating the nickel foam to remove surface oxides; then loading Ni nanoparticles on the pre-treated nickel foam by electrochemical deposition; then treating the above by cyclic voltammetry to obtain an activated sample; finally, obtaining a Ni(OH)2 / Ni(0) composite hydrogen evolution catalyst by aging. However, due to the limitations of the specific deposition process, the hydrogen evolution activity of the obtained composite hydrogen evolution catalyst is still limited. For example, a Chinese patent document (application number 202311171166.5) discloses a method for growing nickel-copper alloy nanoparticles on nickel foam, comprising the following steps: first, the cut nickel foam is pretreated by ultrasound in hydrochloric acid, ethanol, and ultrapure water, the treated nickel foam is vacuum dried, and then transferred to a mixed solution of NiCl2·6H2O and Cu(NO3)2·3H2O for electrodeposition. The electrodeposition is carried out in a standard three-electrode electrochemical system (NF, working electrode; platinum electrode, counter electrode; Ag / AgCl, reference electrode) using chronopotentiometry for constant current deposition. During the electrodeposition process, the cathode current range is 100-750 mA cm -2 , anode is 0 mA cm-2 The cathode deposition time is the same as the anodic deposition time, ranging from 600 to 1800 seconds, with a high limit voltage of 0 to 10V and a low limit voltage of 0 to -10V. Due to the large deposition current and small active area, it is difficult to achieve a high hydrogen evolution current density at low overpotentials. Therefore, the development of low-cost, high-catalytic hydrogen evolution electrodes is particularly urgent. Summary of the Invention

[0003] To overcome the problem of insufficient activity of hydrogen evolution electrodes at high current densities in the prior art, the present invention electrodeposits nickel on nickel foam based on a specific deposition system and electrodeposition method, specifically providing a method for preparing a nickel-based self-supporting hydrogen evolution electrode. The nickel deposited layer obtained by this method has high uniformity, a high number of active sites, and excellent hydrogen evolution activity at high current densities.

[0004] In order to achieve the purpose of the present invention, the technical solutions adopted are as follows:

[0005] A method for preparing a nickel-based self-supporting hydrogen evolution electrode comprises the following steps:

[0006] The nickel foam is sequentially immersed in 2-3 mol / L hydrochloric acid, ultrapure water and ethanol solutions and ultrasonicated for 15-20 minutes to obtain a pretreated nickel foam;

[0007] Dissolving nickel chloride hexahydrate and terephthalic acid in N,N-dimethylformamide, stirring uniformly, and ultrasonically treating to prepare an electrolyte, wherein the concentration of nickel chloride hexahydrate in the electrolyte is 0.1-0.15 mol / L, and the concentration of terephthalic acid is 0.1-0.15 mol / L;

[0008] The pretreated nickel foam was immersed in the electrolyte as a working electrode for electrodeposition, a platinum mesh was used as a counter electrode, and an Ag / AgCl electrode was used as a reference electrode. A constant current of -10 to -20 mA was applied for deposition for 1.5 to 2.5 hours.

[0009] After electrodeposition, the loaded nickel foam was washed with DMF, ultrapure water and ethanol, and vacuum dried to obtain a nickel-based self-supporting hydrogen evolution electrode.

[0010] The above-mentioned method of the present invention is based on the design of the electrolyte and combines the control of electrodeposition parameters in a three-electrode system to deposit a nickel-based self-supporting electrode on nickel foam. Not only is the raw material system simple and low-cost, but the synthesis steps are also simple. Most importantly, the design of the self-supporting electrode of the present invention reduces the impedance between the material and the substrate. Its uneven morphology increases the specific surface area of ​​the material and exposes larger active sites. The performance of the prepared hydrogen evolution electrode is comparable to that of precious metal hydrogen evolution electrodes. It has a low hydrogen evolution overpotential at high current density and can meet the needs of industrial applications.

[0011] As a preferred embodiment of the preparation method of the present invention, the size of the nickel foam is 1.0×0.25 cm 2 ~1.0×1.1cm 2 .

[0012] As a preferred embodiment of the preparation method of the present invention, the concentration of nickel chloride hexahydrate in the electrolyte is 0.1 to 0.12 mol L -1 The concentration of terephthalic acid is 0.14-0.15 mol L -1 More preferably, the concentration of nickel chloride hexahydrate in the electrolyte is 0.1 mol L -1 The concentration of terephthalic acid is 0.15 mol L -1 .

[0013] As a preferred embodiment of the preparation method of the present invention, wherein: the electrolyte is prepared by ultrasonic treatment, wherein the ultrasonic power is 20 to 25W L -1 , the ultrasound time is 30 to 60 minutes.

[0014] As a preferred embodiment of the preparation method of the present invention, the electrodeposition time is 1.5 hours.

[0015] As a preferred embodiment of the preparation method of the present invention, the current intensity of the electrodeposition is -15 to -20 mA.

[0016] As a preferred embodiment of the preparation method of the present invention, the current intensity of the electrodeposition is -15 mA.

[0017] Another object of the present invention is to overcome the deficiencies in the prior art and provide a nickel-based self-supporting hydrogen evolution electrode prepared by the preparation method.

[0018] Another object of the present invention is to overcome the deficiencies in the prior art and provide a nickel-based self-supporting hydrogen evolution electrode for use in electrocatalytic water splitting.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] (1) The nickel-based self-supporting catalytic material prepared by the present invention not only has high deposition uniformity, but also fully exposes the active sites and has high catalytic performance. It has good application prospects in the field of electrocatalytic material technology and is expected to improve energy and environmental problems.

[0021] (2) The nickel-based self-supporting hydrogen evolution electrode of the present invention has excellent physical and chemical properties and platinum-like catalytic performance, making it one of the ideal candidates to replace precious metal hydrogen evolution electrodes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 HER activity diagram of the hydrogen evolution electrode in an embodiment of the present invention.

[0023] Figure 2 1 is a Tafel curve of the hydrogen evolution electrode in an embodiment of the present invention.

[0024] Figure 3 NiO is the hydrogen evolution electrode in Example 3 of the present invention. x SEM image of the morphology and structure of / NF-15mA.

[0025] Figure 4 NiO is the hydrogen evolution electrode in Example 2 of the present invention. x SEM image of the morphology and structure of / NF-10mA.

[0026] Figure 5 Schematic diagram of an electrodeposition device in an embodiment of the present invention.

[0027] Figure 6 These are photos of the electrodeposition of the hydrogen evolution electrodes of Example 6, Example 7 and Example 3.

[0028] Figure 7 HER activity diagrams of hydrogen evolution electrodes of Example 6, Example 7 and Example 3.

[0029] Figure 8 HER activity diagrams of hydrogen evolution electrodes of Example 8, Example 9 and Example 3. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the embodiments of the specification.

[0031] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0032] Secondly, the term "one embodiment" or "embodiment" herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in various places throughout this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive of other embodiments.

[0033] Although transition metals are widely used in HER reactions, the form of traditional catalysts is usually powder. When constructing electrodes, they need to be prepared into a suspension in advance and coated on a current collector such as glassy carbon. In addition, in order to improve stability, expensive binders (such as Nafion or PTFE reagents) are also required. However, the addition of polymer binders in experimental operations will seriously reduce the electrochemical performance of the catalyst because it increases the series resistance of the electrocatalyst, inhibits the effective diffusion of electrons and covers part of the active sites of the catalyst. These shortcomings greatly limit the further research and application of catalysts. Therefore, optimizing and improving traditional catalysts has become a key issue in the field of HER. The strategy of nickel-based self-supporting electrocatalysts has successfully solved the above problems. This is because nickel-based self-supporting electrocatalysts have the following advantages: (1) Self-supporting systems often have higher conductivity. For example, nickel foam (NF) is used as the supporting substrate for synthesizing electrocatalysts. The 3D integrated framework of nickel foam itself has high conductivity, which provides a large number of electron transfer channels and is conducive to the rapid occurrence of chemical reactions; (2) Compared with traditional catalysts, self-supporting catalysts grown directly on the substrate in situ are not easy to agglomerate, and the specific surface area is greatly increased, which can expose more active sites, and a large number of active sites are crucial for catalytic reactions; (3) In multi-metal catalyst systems, the synergistic effect between different phases will also greatly promote HER activity; (4) Self-supporting nanostructured electrocatalysts can be directly used as conductive cathodes for HER testing.

[0034] In the traditional coating method, due to the addition of Nafion reagent, the hydrogen evolution activity of the catalyst will be greatly reduced, and the adhesion of the catalyst is poor. The large number of H2 bubbles generated during the HER process will cause the electrocatalyst coated on the surface of the glassy carbon electrode to fall off, thereby affecting subsequent tests.

[0035] The specific preparation method of the hydrogen evolution electrode of the present invention includes the following:

[0036] First, prepare pretreated nickel foam: immerse the nickel foam in 2-3 mol L -1 Ultrasonication in hydrochloric acid, ultrapure water and ethanol solution for 15 to 20 minutes to obtain pretreated nickel foam; the size of the nickel foam is: 1.0×0.25cm 2 ~1.0×1.1cm 2 ; (Nickel foam source: Suzhou Shengernuo Technology Co., Ltd.)

[0037] Secondly, prepare the electrolyte: dissolve nickel chloride hexahydrate (NiCl2·6H2O) and terephthalic acid (PTA) in N,N-dimethylformamide (DMF). The concentration of nickel chloride hexahydrate in the electrolyte system is calculated to be 0.1 mol / L, and the concentration of terephthalic acid is 0.15 mol L -1(Experimental verification shows that the concentration of nickel chloride hexahydrate in the electrolyte system is 0.1-0.12 mol L -1 The concentration of terephthalic acid is 0.14-0.15 mol L -1 In the three-electrode system of Example 3, the performance of the hydrogen evolution electrode obtained is more than 98% of that of Example 3. The dissolution method can be a commonly used method in the art. The electrolyte dissolution in the following examples adopts: the material system is stirred for 30 minutes, and finally placed in an ultrasonic bath for 120 minutes to ensure sufficient dissolution.

[0038] Then, a nickel-based self-supporting hydrogen evolution electrode material with an ampere-level current density was prepared: the pretreated nickel foam was immersed in an electrolyte as a working electrode, a platinum mesh was used as a counter electrode, and an Ag / AgCl electrode was used as a reference electrode. Different currents were applied using a three-electrode system chronopotentiometry (CP) for deposition for 1.5 hours (experimental verification shows that the deposition effect is relatively good when the deposition time is within the range of 1.5 to 2.5 hours. However, if it exceeds this range, the deposition effect will deteriorate. For example, if the deposition time is too long (over 2.5 hours) or the deposition amount is too large, the active material is likely to fall off; if the deposition time is too short, uneven deposition is likely to occur). After electrodeposition, the loaded nickel foam was repeatedly washed with DMF, ultrapure water, and ethanol, and vacuum dried (for 4-6 hours at a temperature of 50-60°C) to obtain the hydrogen evolution electrode. (The platinum mesh was sourced from Shanghai Leton Industrial Co., Ltd., and the electrodeposition voltage was 1 to 8 V, which is a direct current.)

[0039] Finally, the prepared hydrogen evolution electrode was electrochemically tested using a three-electrode electrolyzer reaction device to test its water-hydrogen decomposition performance.

[0040] Electrochemical water splitting performance evaluation:

[0041] Tested by Donghua electrochemical workstation;

[0042] In the three-electrode system, the working electrode is nickel foam, the reference electrode is Ag / AgCl electrode, and the counter electrode is platinum mesh. (See the electrodeposition process and workstation diagram for details.) Figure 5 )

[0043] Among them, the three-electrode system studies the two half reactions of water electrolysis, including the reduction reaction at the cathode to produce hydrogen and the oxidation reaction at the anode to produce oxygen.

[0044] The device was tested at room temperature and pressure using 1M KOH as the electrolyte, and the HER performance was tested in a suitable potential range (-1 to -3 V) using the linear sweep voltammetry (LSV) method.

[0045] Then the CV curves were tested continuously at different scan rates (-2 to -3 V);

[0046] Finally, the impedance of the hydrogen evolution electrode was tested.

[0047] Current density based on the macroscopic area of ​​the electrode is 500 / 1000 mA cm -2 As an indicator for evaluating the catalytic activity of the hydrogen evolution electrode.

[0048] Example 1

[0049] Preparation and testing of hydrogen evolution electrode S1:

[0050] The pretreated nickel foam was immersed in the electrolyte as the working electrode, the counter electrode was a platinum mesh, and the reference electrode was an Ag / AgCl electrode. The three-electrode system chronopotentiometry (CP) was used to apply a current of -7.5 mA (corresponding to a deposition voltage of -1.74 V to -2.48 V) for 1.5 h. After electrodeposition, the loaded nickel foam was repeatedly washed with DMF, ultrapure water, and ethanol. After vacuum drying (time 4-6 h, temperature 50-60 ° C), the hydrogen evolution electrode S1, referred to as NiO x / NF-7.5.

[0051] The above NiO x / NF-7.5 was tested for electrochemical moisture decomposition and hydrogen. It was found that NiO x / NF-7.5 has certain catalytic properties.

[0052] For HER, the NiO x / NF-7.5 driven at 500 / 1000 mA cm in 1 M KOH electrolyte -2 The overpotentials of the current densities are 242 / 301 mV, respectively.

[0053] Example 2:

[0054] Preparation and testing of S2 hydrogen evolution electrode:

[0055] The pretreated nickel foam was immersed in the electrolyte as the working electrode, the counter electrode was a platinum mesh, and the reference electrode was an Ag / AgCl electrode. The three-electrode system chronopotentiometry (CP) was used to apply a current of -10 mA (corresponding to a deposition voltage of -2.66 V to -2.05 V) for 1.5 h. After electrodeposition, the loaded nickel foam was repeatedly washed with DMF, ultrapure water, and ethanol. After vacuum drying (time 4-6 h, temperature 50-60 ° C), the hydrogen evolution electrode S2, referred to as NiO x / NF-10.

[0056] After the above hydrogen evolution electrode was subjected to electrochemical water decomposition hydrogen test, it was found that NiO x / NF-10 has certain catalytic performance. For HER, NiO x / NF-10 driven at 500 / 1000 mA cm in 1 M KOH electrolyte -2 The overpotentials of the current densities are 193 / 256 mV, respectively.

[0057] from Figure 4 It can be seen that NiO x / NF-10 has a loose leaf-like morphology. Figure 3 In comparison, its morphology is loose, which is not conducive to sufficient infiltration of the electrolyte and exposure of active sites.

[0058] Example 3:

[0059] Preparation and testing of S3 hydrogen evolution electrode

[0060] The pretreated nickel foam was immersed in the electrolyte as the working electrode, the counter electrode was a platinum mesh, and the reference electrode was an Ag / AgCl electrode. The three-electrode system chronopotentiometry (CP) was used to apply a current of -15 mA (corresponding to a deposition voltage of -2.53 to -3.48 V) for 1.5 h. After electrodeposition, the loaded nickel foam was repeatedly washed with DMF, ultrapure water, and ethanol, and vacuum dried (time 4-6 h, temperature 50-60 ° C) to obtain S3, referred to as NiO x / NF-15.

[0061] Hydrogen evolution electrode NiO x / NF-15 morphology and structure SEM image see Figure 3 As can be seen from the figure, NiO x The surface of the / NF-15 composite material is rough and uneven, indicating that the grown active material roughens the smooth surface of the nickel foam, increasing the specific surface area of ​​the hydrogen evolution electrode, thereby increasing the contact area between the electrolyte and the hydrogen evolution electrode, exposing more catalytic active sites, and achieving the purpose of improving the catalytic activity of the hydrogen evolution electrode.

[0062] After the above hydrogen evolution electrode was subjected to electrochemical water decomposition hydrogen test, it was found that NiO x / NF-15 has certain catalytic performance. For HER, NiO x / NF-15 driven at 500 / 1000 mA cm in 1 M KOH electrolyte -2 The overpotentials of the current densities are 149 / 173 mV, respectively.

[0063] Example 4:

[0064] Preparation and testing of S4 hydrogen evolution electrode

[0065] The pretreated nickel foam was immersed in the electrolyte as the working electrode, the counter electrode was a platinum mesh, and the reference electrode was an Ag / AgCl electrode. The three-electrode system chronopotentiometry (CP) was used to apply a current of -20 mA (corresponding to a deposition voltage of -4.57 to -3.45 V) for 1.5 h. After electrodeposition, the loaded nickel foam was repeatedly washed with DMF, ultrapure water, and ethanol, and vacuum dried (time 4-6 h, temperature 50-60 ° C) to obtain S4, referred to as NiO x / NF-20.

[0066] After the above hydrogen evolution electrode is subjected to electrochemical water decomposition hydrogen test, it is known that NiO x / NF-20 has certain catalytic performance. For HER, NiO x / NF-20 driven at 500 / 1000 mA cm in 1 M KOH electrolyte -2 The overpotentials of the current densities are 179 / 216 mV, respectively.

[0067] Example 5:

[0068] Preparation and testing of S5 hydrogen evolution electrode

[0069] The pretreated nickel foam was immersed in the electrolyte as the working electrode, the counter electrode was a platinum mesh, and the reference electrode was an Ag / AgCl electrode. The three-electrode system chronopotentiometry (CP) was used to apply a current of -25 mA (corresponding to a deposition voltage of -4.91 to -3.9 V) for 1.5 h. After electrodeposition, the loaded nickel foam was repeatedly washed with DMF, ultrapure water, and ethanol, and vacuum dried (time 4-6 h, temperature 50-60 ° C) to obtain S5, referred to as NiO x / NF-25.

[0070] After the above hydrogen evolution electrode is subjected to electrochemical water decomposition hydrogen test, it is known that NiO x / NF-25 has certain catalytic performance. For HER, NiO x / NF-25 driven at 500 / 1000 mA cm in 1 M KOH electrolyte -2 The overpotentials of the current densities are 206 / 282 mV, respectively.

[0071] The HER activity diagram of hydrogen evolution electrode is shown in Figure 1 As can be seen from the figure, according to η 500 -HER, the catalytic performance of these hydrogen evolution electrodes is in the following order: NiO x / NF-15>NiO x / NF-20>NiO x / NF-10>NiO x / NF-25>NiO x / NF-7.5; press η 1000 -HER, the order of catalytic performance is: NiO x / NF-15>NiO x / NF-20>NiO x / NF-10>NiO x / NF-25>NiO x / NF-7.5;

[0072] Tafel curve of hydrogen evolution electrode (Tafel slope value is obtained by linear fitting using the Tafel equation using the overpotential and corresponding current density data obtained from the LSV curve: η = a + b × logj, where η is the overpotential, a is a constant, b is the Tafel slope, and j is the current density.) See Figure 2 As can be seen from the figure, the Tafel slopes of these hydrogen evolution electrodes are as follows: Ni-MOF-7.5 is 103mV dec -1 , Ni-MOF-10 is 109.4 mV dec -1 , Ni-MOF-15 is 77.1mV dec -1 , Ni-MOF-20 is 124.4 mV dec -1 , Ni-MOF-25 is 139.8 mV dec -1 Among them, Ni-MOF-15 has the smallest Tafel slope, indicating that it has the highest activity.

[0073] Example 6

[0074] Nickel chloride hexahydrate (NiCl2·6H2O) and terephthalic acid (PTA) were fully dissolved in N,N-dimethylformamide (DMF) as the electrolyte (the concentration of nickel chloride hexahydrate in the electrolyte system was calculated to be 0.1 mol L -1 , terephthalic acid concentration 0.1 mol L -1 ), the pretreated nickel foam was immersed in the electrolyte as the working electrode, a platinum mesh was used as the counter electrode, and an Ag / AgCl electrode was used as the reference electrode. The three-electrode system chronopotentiometry (CP) was used to apply a -15 mA current for deposition for 1.5 h. After electrodeposition, the loaded nickel foam was repeatedly washed with DMF, ultrapure water and ethanol, and then vacuum dried (time 4-6 h, temperature 50-60 ° C). After testing, its effect was not good.

[0075] Example 7

[0076] Nickel chloride hexahydrate (NiCl2·6H2O) and terephthalic acid (PTA) were fully dissolved in N,N-dimethylformamide (DMF) as the electrolyte (the concentration of nickel chloride hexahydrate in the electrolyte system was calculated to be 0.2 mol L-1 , terephthalic acid concentration 0.1 mol L -1 ), the pretreated nickel foam was immersed in the electrolyte as the working electrode, a platinum mesh was used as the counter electrode, and an Ag / AgCl electrode was used as the reference electrode. The three-electrode system chronopotentiometry (CP) was used to apply a -15 mA current for deposition for 1.5 h. After electrodeposition, the loaded nickel foam was repeatedly washed with DMF, ultrapure water and ethanol, and then vacuum dried (time 4-6 h, temperature 50-60 ° C). After testing, its effect was not good.

[0077] The deposition uniformity of Examples 6 and 7 is compared with that of Example 3. Figure 6 It can be clearly seen from the figure that the deposition uniformity of Examples 6 and 7 is slightly reduced.

[0078] See Example 6 and 7 activity diagrams. Figure 7 As can be seen from the figure, according to η 500 -HER, the catalytic performance of these hydrogen evolution electrodes is as follows: Example 3> Example 6> Example 7. 1000 -HER, the order of catalytic performance is: Example 3> Example 6> Example 7.

[0079] Example 8

[0080] Nickel chloride hexahydrate (NiCl2·6H2O) and terephthalic acid (PTA) were fully dissolved in N,N-dimethylformamide (DMF) as the electrolyte (the concentration of nickel chloride hexahydrate in the electrolyte system was calculated to be 0.15 mol L -1 , terephthalic acid concentration 0.2 mol L -1 ), the pretreated nickel foam was immersed in the electrolyte as the working electrode, a platinum mesh was used as the counter electrode, and an Ag / AgCl electrode was used as the reference electrode. The three-electrode system chronopotentiometry (CP) was used to apply a -15 mA current for deposition for 1.5 h. After electrodeposition, the loaded nickel foam was repeatedly washed with DMF, ultrapure water and ethanol, and then vacuum dried (time 4-6 h, temperature 50-60 ° C). After testing, its effect was not good.

[0081] Example 9

[0082] Nickel chloride hexahydrate (NiCl2·6H2O) and terephthalic acid (PTA) were fully dissolved in N,N-dimethylformamide (DMF) as the electrolyte (the concentration of nickel chloride hexahydrate in the electrolyte system was calculated to be 0.15 mol L -1 , terephthalic acid concentration 0.15 mol L -1), the pretreated nickel foam was immersed in the electrolyte as the working electrode, a platinum mesh was used as the counter electrode, and an Ag / AgCl electrode was used as the reference electrode. The three-electrode system chronopotentiometry (CP) was used to apply a -15 mA current for deposition for 1.5 h. After electrodeposition, the loaded nickel foam was repeatedly washed with DMF, ultrapure water and ethanol, and then vacuum dried (time 4-6 h, temperature 50-60 ° C). After testing, its effect was not good.

[0083] See Example 8 and 9 activity diagrams. Figure 8 As can be seen from the figure, according to η 500 -HER, the catalytic performance of these hydrogen evolution electrodes is as follows: Example 3> Example 9> Example 8. 1000 -HER, the order of catalytic performance is: Example 3> Example 9> Example 8.

[0084] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, and all of these should be included in the scope of the present invention.

Claims

1. A method for preparing a nickel-based self-supporting hydrogen evolution electrode, characterized in that: The following steps are included: The nickel foam is sequentially immersed in 2-3 mol / L hydrochloric acid, ultrapure water and ethanol solutions and ultrasonicated for 15-20 minutes to obtain a pretreated nickel foam; Dissolving nickel chloride hexahydrate and terephthalic acid in N,N-dimethylformamide, stirring uniformly, and ultrasonically treating to prepare an electrolyte; the concentration of nickel chloride hexahydrate in the electrolyte is 0.1-0.15 mol / L, and the concentration of terephthalic acid is 0.1-0.15 mol / L; The pretreated nickel foam was immersed in an electrolyte as a working electrode for electrodeposition, a platinum mesh was used as a counter electrode, and an Ag / AgCl electrode was used as a reference electrode. A current of -10 to -20 mA was applied for deposition for 1.5 to 2.5 hours. After the electrodeposition, the nickel foam was washed with DMF, ultrapure water and ethanol in sequence, and then dried in vacuum to obtain a nickel-based self-supporting hydrogen evolution electrode.

2. The method for preparing a nickel-based self-supporting hydrogen evolution electrode according to claim 1, wherein: The concentration of nickel chloride hexahydrate in the electrolyte is 0.1-0.12 mol / L, and the concentration of terephthalic acid is 0.14-0.15 mol / L.

3. The method for preparing a nickel-based self-supporting hydrogen evolution electrode according to claim 1, wherein: The concentration of nickel chloride hexahydrate in the electrolyte is 0.1 mol / L, and the concentration of terephthalic acid is 0.15 mol / L.

4. The method for preparing a nickel-based self-supporting hydrogen evolution electrode according to claim 1, wherein: The electrolyte is prepared by ultrasonic treatment, wherein the ultrasonic power is 20-25 W / L and the ultrasonic time is 30-60 min.

5. The method for preparing a nickel-based self-supporting hydrogen evolution electrode according to claim 1, wherein: The current deposition time was 1.5 h.

6. The method for preparing a nickel-based self-supporting hydrogen evolution electrode according to claim 1, wherein: The current intensity of the electrodeposition is -15 to -20 mA.

7. The method for preparing a nickel-based self-supporting hydrogen evolution electrode according to claim 1, wherein: The current intensity of the electrodeposition was -15 mA.

8. A nickel-based self-supporting hydrogen evolution electrode prepared by the method for preparing a nickel-based self-supporting hydrogen evolution electrode according to any one of claims 1 to 7.

9. Use of the nickel-based self-supporting hydrogen evolution electrode according to claim 8 in electrocatalytic water decomposition.

10. Use of the nickel-based self-supporting hydrogen evolution electrode according to claim 9 in electrocatalytic water decomposition, characterized in that: This includes controlling the current density of electrocatalytic water splitting to be 500-1000 mA cm in an alkaline environment. -2 .

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