Nickel-molybdenum-based self-supporting hydrogen evolution electrode and preparation method and application thereof

Abstract

The invention relates to a nickel-molybdenum-based self-supporting hydrogen evolution electrode and a preparation method and application thereof.The preparation method comprises the following steps that a substrate is placed in a water bath reaction solution to be subjected to a water bath reaction, and a water bath reaction precursor is obtained after the water bath reaction is finished; and carrying out nitriding treatment on the water bath reaction precursor to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode, the water bath reaction comprises at least two heating processes, and cooling is carried out between two adjacent heating processes. Through at least two times of heating in the water bath reaction process, a mutually cross-linked and supported nanorod structure is formed, the technological process is simplified, the preparation period of the electrode is shortened, and the electrode has good electrochemical activity and mechanical strength; the water bath reaction is matched with the nitriding treatment, so that the oxygen element in the precursor can be eliminated, the Ni-Mo electronic structure is regulated and controlled, and the catalytic activity and the stability of the self-supporting hydrogen evolution electrode are improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen production by water electrolysis, and relates to a self-supporting hydrogen evolution electrode, in particular to a nickel-molybdenum-based self-supporting hydrogen evolution electrode and a preparation method and application thereof. BACKGROUND

[0002] The acceleration of social industrialization has caused the overconsumption of fossil energy, and a series of problems such as global climate change, energy crisis, environmental pollution have come and intensified. Therefore, it is urgent to find a clean and renewable alternative energy. Hydrogen is considered to be one of the ideal energy sources for future society due to its high-quality energy density, zero pollution, and renewable advantages. Hydrogen production by water electrolysis not only has the advantages of high efficiency, cleanliness, and convenience, but also helps large-scale consumption of renewable power, and is an ideal way for large-scale hydrogen production in the future, so it has attracted widespread attention from the academic and industrial communities.

[0003] Currently, most commercial hydrogen evolution electrocatalysts are noble metal catalysts such as platinum and ruthenium, which exhibit good hydrogen evolution activity, but their high price and low reserves limit their large-scale development and industrial application. CN219689888U discloses an electrolytic water hydrogen production coating electrode with an embedded installation structure, which has a HER overpotential of only 1.0899V relative to a saturated calomel electrode at a current density of 4000A / m 2 . However, the use of platinum and ruthenium noble metals makes the cost high. Therefore, it is of great research value to develop low-cost and high-performance hydrogen evolution electrodes.

[0004] Nickel-molybdenum alloy is a binary non-noble metal alloy with high hydrogen evolution catalytic activity in alkaline aqueous solution, and has the advantages of easy availability of raw materials and low cost. The current common preparation method of nickel-molybdenum-based self-supporting hydrogen evolution electrodes is to first load nickel molybdate nanorods with hydrogen evolution activity on the self-supporting material through hydrothermal synthesis, and then to improve the electrochemical stability of the electrode material by doping non-metallic elements through gas deposition. For example, CN109926082A discloses a carbon-coated nickel molybdenum nitride composite material and a preparation method thereof. The preparation method first prepares carbon-coated NiMoN alloy phases with excellent hydrogen evolution activity and oxidation resistance through two steps of hydrothermal synthesis and high-temperature pyrolysis. The overpotential is only 36mV at a hydrogen evolution current density of 10mA / cm 2 . However, this preparation method requires the use of a high-temperature and high-pressure hydrothermal reactor, which is difficult to realize industrial production, and at the industrial standard current density, these independently grown nanorods are easily damaged by hydrogen bubbles.

[0005] Therefore, it is crucial to reduce the preparation difficulty and enhance the mechanical stability of nickel-molybdenum-based nanorods while maintaining or even improving the hydrogen reaction activity. SUMMARY

[0006] The present application aims to provide a nickel-molybdenum-based self-supporting hydrogen evolution electrode and a preparation method and application thereof, wherein the preparation method has low cost, does not require complex equipment in the preparation process, can simplify the process flow and shorten the preparation period of the electrode, and can guarantee the electrochemical activity and mechanical strength of the obtained nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0007] To achieve the object of the present application, the following technical solutions are adopted in the present application:

[0008] In a first aspect, the present application provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, which comprises the following steps:

[0009] The substrate is placed in a water bath reaction solution for water bath reaction, and a water bath reaction precursor is obtained after the water bath reaction; and the water bath reaction precursor is subjected to nitriding treatment to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0010] The water bath reaction comprises at least two temperature rising processes, and a temperature falling process is performed between adjacent two temperature rising processes.

[0011] The preparation method provided by the present application has low cost, does not require complex equipment in the preparation process, can simplify the process flow and shorten the preparation period of the electrode, and can guarantee the electrochemical activity and mechanical strength of the obtained nickel-molybdenum-based self-supporting hydrogen evolution electrode. Specifically, the present application forms a nano-pillar structure supported by mutual cross-linking through at least two temperature rising processes in the hydrothermal reaction, simplifies the process flow, shortens the preparation period of the electrode, and has good electrochemical activity and mechanical strength; through the cooperation of the water bath reaction and the nitriding treatment, the oxygen element in the precursor can be eliminated, and the Ni-Mo electronic structure can be regulated, thereby improving the catalytic activity and stability of the self-supporting hydrogen evolution electrode.

[0012] Illustratively, the substrate comprises a metal wire mesh or a nickel foam.

[0013] Preferably, the end point temperature of the first temperature rising is 80-110℃, for example, it can be 80℃, 85℃, 90℃, 95℃, 100℃, 105℃ or 110℃, but is not limited to the listed values, and other values not listed in the value range are also applicable, and preferably 90-110℃.

[0014] Preferably, the time of the first temperature holding is 1-9h, for example, it can be 1h, 3h, 5h, 6h, 8h or 9h, but is not limited to the listed values, and other values not listed in the value range are also applicable, and preferably 1-6h.

[0015] In the present application, the temperature of the first temperature holding is the same as the end point temperature of the first temperature rising.

[0016] Preferably, the end temperature of the temperature reduction is 30-70℃, for example, it can be 30℃, 40℃, 50℃, 60℃, 70℃, 80℃ or 90℃, but is not limited to the listed values, other values not listed in the value range are also applicable, preferably 50-70℃.

[0017] Preferably, the end temperature of the second temperature increase is 80-110℃, for example, it can be 80℃, 85℃, 90℃, 95℃, 100℃, 105℃ or 110℃, but is not limited to the listed values, other values not listed in the value range are also applicable, preferably 90-110℃.

[0018] Preferably, the second holding time is 0.5-4h, for example, it can be 0.5h, 1h, 2h, 3h or 4h, but is not limited to the listed values, other values not listed in the value range are also applicable, preferably 0.5-2h.

[0019] In the present application, the temperature of the second holding is the same as the end temperature of the second temperature increase.

[0020] The water bath reaction of the present application does not need to be carried out under high temperature and high pressure conditions, and the preparation of the nickel-molybdenum-based self-supporting hydrogen evolution electrode can be realized in a water bath reaction with mild conditions; moreover, through the control of temperature during the preparation process, at least the secondary growth of NiMoO4 is achieved, which reduces the equipment requirements and cost and simplifies the process flow; moreover, the at least 2 times of temperature increase process can further grow finer nanorods in the gap between the nanorods grown previously, and the at least 2 times of grown nanorods are cross-linked to support each other, which improves the mechanical strength of the nanoclusters and solves the problem of powder falling.

[0021] Preferably, the nitriding treatment is carried out using a gaseous nitrogen source and / or a solid nitrogen source.

[0022] The nitriding treatment adopted in the present application can be carried out using a gaseous nitrogen source alone, or using a solid nitrogen source alone, or using a gaseous nitrogen source and a solid nitrogen source in cooperation. If only a single nitrogen source is used, the synergistic effect between the gaseous nitrogen source and the solid nitrogen source cannot be exerted, therefore, as a further preferred technical solution, the nitriding treatment of the present application is carried out using a gaseous nitrogen source and a solid nitrogen source, the simultaneous use of the gaseous nitrogen source and the solid nitrogen source can coordinate the electronic structure, greatly improving the electrocatalytic activity and stability of the electrode.

[0023] Preferably, the gaseous nitrogen source comprises ammonia.

[0024] Preferably, the solid nitrogen source comprises any one or a combination of at least two of melamine, dicyandiamide, polyaniline or polypyrrole, typically but not limited to combinations of melamine and dicyandiamide, polyaniline and polypyrrole, dicyandiamide and polyaniline, melamine, dicyandiamide and polyaniline, dicyandiamide, polyaniline and polypyrrole, or melamine, dicyandiamide, polyaniline and polypyrrole.

[0025] Preferably, the nitriding treatment is at a temperature of 400-1000°C, for example, it can be 400°C, 500°C, 600°C, 800°C or 1000°C, but is not limited to the listed values, other values not listed within the range of values are also applicable, for example, it can be 700-1000°C.

[0026] Preferably, the nitriding treatment is for a time of 1-5h, for example, it can be 1h, 2h, 3h, 4h or 5h, but is not limited to the listed values, other values not listed within the range of values are also applicable, for example, it can be 1-3h.

[0027] Preferably, the nitriding treatment is performed in an atmosphere furnace.

[0028] Preferably, when the nitriding treatment is performed using a gaseous nitrogen source, a protective gas is simultaneously introduced together with the gaseous nitrogen source.

[0029] Preferably, when the nitriding treatment is performed using a gaseous nitrogen source, the flow rate ratio of the protective gas to the gaseous nitrogen source is 1:(0.1-10), for example, it can be 1:0.1, 1:0.5, 1:1, 1:3, 1:5, 1:6, 1:8 or 1:10, but is not limited to the listed values, other values not listed within the range of values are also applicable.

[0030] Preferably, when the nitriding treatment is performed using a solid nitrogen source, the weight ratio of the solid nitrogen source to the water bath reaction load is 1:(0.1-10), for example, it can be 1:0.1, 1:0.5, 1:1, 1:3, 1:5, 1:6, 1:8 or 1:10, but is not limited to the listed values, other values not listed within the range of values are also applicable.

[0031] Preferably, when the nitriding treatment is performed using both a solid nitrogen source and a gaseous nitrogen source, a protective gas is simultaneously introduced together with the gaseous nitrogen source.

[0032] Preferably, when the nitriding treatment is performed using both a solid nitrogen source and a gaseous nitrogen source, the flow rate ratio of the protective gas to the gaseous nitrogen source is 1:(0.1-5), and the weight ratio of the solid nitrogen source to the water bath reaction load is 1:(0.1-5).

[0033] In the present application, when the nitriding treatment is simultaneously performed using the solid nitrogen source and the gaseous nitrogen source, the flow ratio of the protective gas to the gaseous nitrogen source is 1:(0.1-5), for example, it can be 1:0.1, 1:0.5, 1:1, 1:2, 1:3, 1:4 or 1:5, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0034] In the present application, when the nitriding treatment is simultaneously performed using the solid nitrogen source and the gaseous nitrogen source, the weight ratio of the solid nitrogen source to the water bath reaction load is 1:(0.1-5), for example, it can be 1:0.1, 1:0.5, 1:1, 1:2, 1:3, 1:4 or 1:5, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0035] The water bath reaction load in the present application refers to the mass of the substrate participating in the water bath reaction as m1, the mass of the water bath reaction precursor as m2, and the water bath reaction load as m2-m1.

[0036] The protective gas in the present application includes any one or a combination of at least two of nitrogen, helium, neon or argon, and typical but non-limiting combinations include a combination of nitrogen and helium, a combination of helium and neon, a combination of helium and argon, a combination of helium and argon, a combination of nitrogen, helium and argon, or a combination of nitrogen, helium, neon and argon.

[0037] For example, when the nitriding treatment is performed in an atmosphere furnace, the solid nitrogen source is placed upstream of the water bath reaction precursor.

[0038] According to the flow direction of the gas in the atmosphere furnace during the nitriding treatment, the solid nitrogen source is placed at the front end of the water bath reaction precursor, i.e. upstream, which can ensure that the nitrogen-containing organic matter generated by the decomposition of the solid nitrogen source is carried by the gas stream, so that it can react with the water bath reaction precursor.

[0039] Preferably, the water bath reaction solution comprises a nickel source, a molybdenum source, a carbon source and a solvent.

[0040] In the present application, a carbon source is added to the water bath reaction solution, which can form a thin layer of amorphous carbon on the surface of the electrode during high-temperature nitriding, which can effectively prevent the contact of oxygen with the active sites, thereby improving the oxidation resistance of the electrode.

[0041] Preferably, the molar ratio of the nickel source, the molybdenum source, the carbon source and the solvent is 1:(1-10):(0.1-10):(100-10000).

[0042] The molar ratio of the nickel source to the solvent in the water bath reaction solution is 1 : (100-10000), for example, it can be 1 : 100, 1 : 500, 1 : 1000, 1 : 3000, 1 : 5000, 1 : 6000, 1 : 8000 or 1 : 10000, but is not limited to the listed values, other values not listed within the value range are also applicable, preferably 1 : (500-10000).

[0043] The molar ratio of the nickel source to the solvent in the water bath reaction solution is 1 : (100-10000), for example, it can be 1 : 100, 1 : 500, 1 : 1000, 1 : 3000, 1 : 5000, 1 : 6000, 1 : 8000 or 1 : 10000, but is not limited to the listed values, other values not listed within the value range are also applicable, preferably 1 : (500-10000).

[0044] The molar ratio of the nickel source to the solvent in the water bath reaction solution is 1 : (100-10000), for example, it can be 1 : 100, 1 : 500, 1 : 1000, 1 : 3000, 1 : 5000, 1 : 6000, 1 : 8000 or 1 : 10000, but is not limited to the listed values, other values not listed within the value range are also applicable, preferably 1 : (500-10000).

[0045] Preferably, the nickel source includes any one or a combination of at least two of nickel sulfate, nickel chloride, nickel nitrate, nickel acetate, carbonyl nickel, nickel protoxide hydroxide or nickel carbonate, typical but non-limiting combinations include a combination of nickel sulfate and nickel chloride, a combination of nickel nitrate and nickel acetate, a combination of carbonyl nickel and nickel protoxide hydroxide, a combination of nickel acetate and nickel carbonate, a combination of nickel sulfate, nickel chloride or nickel nitrate, a combination of nickel acetate, carbonyl nickel, nickel protoxide hydroxide and nickel carbonate, or a combination of nickel sulfate, nickel chloride, nickel nitrate, nickel acetate, carbonyl nickel, nickel protoxide hydroxide and nickel carbonate.

[0046] Preferably, the molybdenum source includes any one or a combination of at least two of sodium molybdate, ammonium molybdate, magnesium molybdate or zinc molybdate, typical but non-limiting combinations include a combination of sodium molybdate and ammonium molybdate, a combination of magnesium molybdate and zinc molybdate, a combination of sodium molybdate and magnesium molybdate, a combination of sodium molybdate, ammonium molybdate and magnesium molybdate, or a combination of sodium molybdate, ammonium molybdate, magnesium molybdate and zinc molybdate.

[0047] Preferably, the carbon source includes any one or a combination of at least two of polyvinylpyrrolidone (PVP), glucose, urea, dopamine, protein, dicyandiamide, polyphenylene sulfide (PPS) or polysulfone (PSF), typical but non-limiting combinations include a combination of PVP and glucose, a combination of urea and dopamine, a combination of protein and dicyandiamide, a combination of PPS and PSF, a combination of PVP, PPS and PSF, a combination of glucose, urea and dopamine, or a combination of PVP, glucose, urea, dopamine, protein, dicyandiamide, PPS and PSF.

[0048] Preferably, the solvent includes water.

[0049] Preferably, the substrate comprises at least one of nickel foam, nickel mesh, stainless steel mesh, titanium mesh, nickel alloy foam, or nickel alloy mesh.

[0050] Before use, the substrate described in this invention undergoes conventional alkaline washing, acid washing, and water washing to remove oil and oxide film from the substrate surface. When the substrate surface used in this invention does not have oil and oxide film, alkaline washing, acid washing, and water washing are not required. This invention does not further limit the alkaline washing, acid washing, and water washing operations, as long as they can remove oil and oxide film from the substrate surface.

[0051] In a second aspect, the present invention provides a nickel-molybdenum-based self-supporting hydrogen evolution electrode, wherein the nickel-molybdenum-based self-supporting hydrogen evolution electrode is prepared by the preparation method described in the first aspect.

[0052] Thirdly, the present invention provides an application of the nickel-molybdenum-based self-supporting hydrogen evolution electrode as described in the second aspect, wherein the nickel-molybdenum-based self-supporting hydrogen evolution electrode is used for hydrogen production by water electrolysis.

[0053] Compared with the prior art, the present invention has the following beneficial effects:

[0054] The preparation method provided by this invention has low cost, requires no complex equipment, simplifies the process, shortens the electrode preparation cycle, and ensures the electrochemical activity and mechanical strength of the obtained nickel-molybdenum-based self-supporting hydrogen evolution electrode. Specifically, this invention forms a cross-linked and supported nanopillar structure through at least two heating cycles in the hydrothermal reaction, simplifying the process, shortening the electrode preparation cycle, and exhibiting good electrochemical activity and mechanical strength. By combining the water bath reaction with nitriding treatment, oxygen elements in the precursor can be eliminated, and the electronic structure of Ni-Mo can be regulated, thereby improving the catalytic activity and stability of the self-supporting hydrogen evolution electrode. Attached Figure Description

[0055] Figure 1 SEM image of the nickel-molybdenum-based self-supporting hydrogen evolution electrode obtained in Example 1;

[0056] Figure 2 The image shows a SEM image of the nickel-molybdenum-based self-supporting hydrogen evolution electrode obtained in Comparative Example 1. Detailed Implementation

[0057] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0058] The foam nickel used in the embodiment of the present application has a porosity of 100 PPI and a thickness of 0.8 mm after removing the oil stains and oxide film present on the surface of the substrate.

[0059] The characterization tests in the present application include mechanical strength tests and hydrogen evolution catalytic activity tests, wherein:

[0060] The test method for mechanical strength is as follows: the obtained nickel-molybdenum-based self-supporting hydrogen evolution electrode is cut into small pieces of 3*4 cm, which are placed in a glass beaker, 200 mL of pure water is added, and ultrasonic treatment is performed at 27℃ for 30 min at 100% power. The mass of the nickel-molybdenum-based self-supporting hydrogen evolution electrode before and after ultrasonic treatment is measured to obtain the ultrasonic weight loss rate.

[0061] The test method for hydrogen evolution catalytic activity is as follows: the obtained nickel-molybdenum-based self-supporting hydrogen evolution electrode is cut into small pieces of 1*1 cm with tabs, the test temperature is 27℃, the electrolyte is 1 mol / L KOH solution, and a three-electrode test is performed. The overpotential μ 2 and μ 2 are measured when the current density is 10 mA / cm 10 and 100 mA / cm 100 , respectively.

[0062] Example 1

[0063] The present embodiment provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, which comprises the following steps:

[0064] (1) 0.73 g of foam nickel is placed in a water bath reaction solution for water bath reaction. After the water bath reaction is completed, the water bath reaction precursor is obtained by ultrapure water washing and drying, and the weight of the water bath reaction precursor is 1.73 g;

[0065] The water bath reaction comprises heating to 90℃ for 6 h, naturally cooling to 50℃, and then heating to 90℃ again for 2 h;

[0066] The water bath reaction solution comprises nickel nitrate, ammonium molybdate, urea and water in a molar ratio of 1:5:2:500;

[0067] (2) The water bath reaction precursor is subjected to nitriding treatment in an atmosphere furnace to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode;

[0068] The nitriding treatment comprises: placing 1 g of dicyandiamide powder upstream of the atmosphere furnace and placing the water bath reaction precursor downstream of the atmosphere furnace, vacuumizing and then introducing argon, and repeating the process 5 times to remove air in the atmosphere furnace; then introducing Ar and NH3 into the atmosphere furnace at flow rates of 55 sccm and 55 sccm, respectively, heating to 700℃ at a rate of 5℃ / min and maintaining for 3 h, and cooling to room temperature to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0069] The SEM image of the obtained nickel-molybdenum-based self-supporting hydrogen evolution electrode is shown in FIG. 1. Figure 1

[0070] Embodiment 2

[0071] The embodiment provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, and the preparation method comprises the following steps:

[0072] (1) 0.73 g of foamed nickel is placed in a water bath reaction solution for water bath reaction, after the water bath reaction is completed, the water bath reaction precursor is obtained by washing with ultrapure water and drying, wherein the water bath reaction precursor is 2.53 g;

[0073] The water bath reaction comprises the following steps: heating to 80 DEG C and keeping for 9 h, naturally cooling to 30 DEG C, and then heating to 80 DEG C again and keeping for 4 h;

[0074] The water bath reaction solution comprises nickel nitrate, ammonium molybdate, urea and water in a molar ratio of 1:1:0.1:100;

[0075] (2) The water bath reaction precursor is subjected to nitriding treatment in an atmosphere furnace, and the nickel-molybdenum-based self-supporting hydrogen evolution electrode is obtained;

[0076] The nitriding treatment comprises the following steps: 18 g of dicyandiamide powder is placed upstream of the atmosphere furnace, the water bath reaction precursor is placed downstream of the atmosphere furnace, vacuum is drawn, and then argon is introduced, and the above steps are repeated for 5 times to remove air in the atmosphere furnace; then Ar and NH3 are introduced into the atmosphere furnace at flow rates of 100 sccm and 10 sccm respectively, heating is performed at a rate of 5 DEG C / min to 400 DEG C and keeping for 5 h, and then the nickel-molybdenum-based self-supporting hydrogen evolution electrode is obtained after cooling to room temperature.

[0077] Embodiment 3

[0078] The embodiment provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, and the preparation method comprises the following steps:

[0079] (1) 0.73 g of foamed nickel is placed in a water bath reaction solution for water bath reaction, after the water bath reaction is completed, the water bath reaction precursor is obtained by washing with ultrapure water and drying, wherein the water bath reaction precursor is 2.53 g;

[0080] The water bath reaction comprises the following steps: heating to 80 DEG C and keeping for 9 h, naturally cooling to 30 DEG C, and then heating to 80 DEG C again and keeping for 4 h;

[0081] The water bath reaction solution comprises nickel nitrate, ammonium molybdate, urea and water in a molar ratio of 1:1:0.1:100;

[0082] (2) The water bath reaction precursor is subjected to nitriding treatment in an atmosphere furnace, and the nickel-molybdenum-based self-supporting hydrogen evolution electrode is obtained;

[0083] ​The nitriding treatment comprises: placing 0.1 g of dicyandiamide powder upstream of the atmosphere furnace, placing the water bath reaction precursor downstream of the atmosphere furnace, introducing argon after vacuumizing, and repeating 5 times to discharge air in the atmosphere furnace; then introducing Ar and NH3 into the atmosphere furnace at flow rates of 18 sccm and 90 sccm respectively, heating to 1000 ℃ at a rate of 5 ℃ / min and keeping for 1 h, and cooling to room temperature to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0084] Example 4

[0085] The preparation method of the nickel-molybdenum-based self-supporting hydrogen evolution electrode provided in the example comprises the following steps:

[0086] The nitriding treatment in the example comprises: placing 1 g of dicyandiamide powder upstream of the atmosphere furnace, placing the water bath reaction precursor downstream of the atmosphere furnace, introducing argon after vacuumizing, and repeating 5 times to discharge air in the atmosphere furnace; then introducing Ar into the atmosphere furnace at a flow rate of 110 sccm, heating to 700 ℃ at a rate of 5 ℃ / min and keeping for 3 h, and cooling to room temperature to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0087] Example 5

[0088] The preparation method of the nickel-molybdenum-based self-supporting hydrogen evolution electrode provided in the example comprises the following steps:

[0089] The nitriding treatment in the example comprises: placing 10 g of dicyandiamide powder upstream of the atmosphere furnace, placing the water bath reaction precursor downstream of the atmosphere furnace, introducing argon after vacuumizing, and repeating 5 times to discharge air in the atmosphere furnace; then introducing Ar into the atmosphere furnace at a flow rate of 110 sccm, heating to 700 ℃ at a rate of 5 ℃ / min and keeping for 3 h, and cooling to room temperature to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0090] Example 6

[0091] The preparation method of the nickel-molybdenum-based self-supporting hydrogen evolution electrode provided in the example comprises the following steps:

[0092] The nitriding treatment in the example comprises: placing 0.1 g of dicyandiamide powder upstream of the atmosphere furnace, placing the water bath reaction precursor downstream of the atmosphere furnace, introducing argon after vacuumizing, and repeating 5 times to discharge air in the atmosphere furnace; then introducing Ar into the atmosphere furnace at a flow rate of 110 sccm, heating to 700 ℃ at a rate of 5 ℃ / min and keeping for 3 h, and cooling to room temperature to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0093] Example 7

[0094] The embodiment provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, wherein the preparation method is the same as that in Embodiment 1 except that the nitriding treatment is different from that in Embodiment 1.

[0095] The nitriding treatment in the embodiment comprises the following steps: placing a water bath reaction precursor in an atmosphere furnace, introducing argon after vacuumizing, and repeating the operation for 5 times to discharge air in the atmosphere furnace; then introducing Ar and NH3 into the atmosphere furnace at flow rates of 55 sccm and 55 sccm respectively, and heating to 700 ℃ at a rate of 5 ℃ / min and keeping for 3 h, and cooling to room temperature to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0096] Embodiment 8

[0097] The embodiment provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, wherein the preparation method is the same as that in Embodiment 1 except that the nitriding treatment is different from that in Embodiment 1.

[0098] The nitriding treatment in the embodiment comprises the following steps: placing a water bath reaction precursor in an atmosphere furnace, introducing argon after vacuumizing, and repeating the operation for 5 times to discharge air in the atmosphere furnace; then introducing Ar and NH3 into the atmosphere furnace at flow rates of 55 sccm and 55 sccm respectively, and heating to 700 ℃ at a rate of 5 ℃ / min and keeping for 3 h, and cooling to room temperature to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0099] Embodiment 9

[0100] The embodiment provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, wherein the preparation method is the same as that in Embodiment 1 except that the nitriding treatment is different from that in Embodiment 1.

[0101] The nitriding treatment in the embodiment comprises the following steps: placing a water bath reaction precursor in an atmosphere furnace, introducing argon after vacuumizing, and repeating the operation for 5 times to discharge air in the atmosphere furnace; then introducing Ar and NH3 into the atmosphere furnace at flow rates of 55 sccm and 55 sccm respectively, and heating to 700 ℃ at a rate of 5 ℃ / min and keeping for 3 h, and cooling to room temperature to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0102] Embodiment 10

[0103] The embodiment provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, wherein the preparation method is the same as that in Embodiment 1 except that the urea is replaced by polyvinylpyrrolidone (Shanghai Aladdin Bio-Chem Technology Co., Ltd., P110607) in equal molar amount.

[0104] The water bath reaction load in the embodiment is 1.32 g, and the amount of dicyandiamide powder is adjusted so that the weight ratio of dicyandiamide powder to water bath reaction load is 1:1.

[0105] Example 11

[0106] The present example provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, which is the same as example 1 except that the equimolar amount of urea is replaced by glucose (CAS: 50-99-7).

[0107] The water bath reaction load of the present example is 0.86 g, and the amount of dicyandiamide powder is adjusted correspondingly so that the weight ratio of dicyandiamide powder to water bath reaction load is 1:1.

[0108] Example 12

[0109] The present example provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, which is the same as example 1 except that no urea is added to the water bath reaction solution.

[0110] The water bath reaction load of the present example is 0.93 g, and the amount of dicyandiamide powder is adjusted correspondingly so that the weight ratio of dicyandiamide powder to water bath reaction load is 1:1.

[0111] Example 13

[0112] The present example provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, which is the same as example 1 except that the water bath reaction is different from example 1.

[0113] The water bath reaction of the present example includes: warming to 70°C for 6h, naturally cooling to 50°C, and then warming to 90°C for 2h again.

[0114] The water bath reaction load of the present example is 0.77 g, and the amount of dicyandiamide powder is adjusted correspondingly so that the weight ratio of dicyandiamide powder to water bath reaction load is 1:1.

[0115] Example 14

[0116] The present example provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, which is the same as example 1 except that the water bath reaction is different from example 1.

[0117] The water bath reaction of the present example includes: warming to 120°C for 6h, naturally cooling to 50°C, and then warming to 90°C for 2h again.

[0118] The water bath reaction load of the present example is 1.07 g, and the amount of dicyandiamide powder is adjusted correspondingly so that the weight ratio of dicyandiamide powder to water bath reaction load is 1:1.

[0119] Although the present example can achieve the preparation of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, the high temperature will increase the cost of equipment.

[0120] Example 15

[0121] The embodiment provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, which is identical to that in the embodiment 1 except that the water bath reaction is different from that in the embodiment 1.

[0122] The water bath reaction of the embodiment comprises the following steps: being warmed to 90 DEG C and being kept for 6h, being naturally cooled to 50 DEG C, being warmed to 70 DEG C again and being kept for 2h.

[0123] The water bath reaction of the embodiment has a loading capacity of 0.81g, and the amount of dicyandiamide powder is adjusted so that the weight ratio of the dicyandiamide powder to the loading capacity of the water bath reaction is 1:1.

[0124] Embodiment 16

[0125] The embodiment provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, which is identical to that in the embodiment 1 except that the water bath reaction is different from that in the embodiment 1.

[0126] The water bath reaction of the embodiment comprises the following steps: being warmed to 90 DEG C and being kept for 6h, being naturally cooled to 50 DEG C, being warmed to 70 DEG C again and being kept for 2h.

[0127] The water bath reaction of the embodiment has a loading capacity of 0.81g, and the amount of dicyandiamide powder is adjusted so that the weight ratio of the dicyandiamide powder to the loading capacity of the water bath reaction is 1:1.

[0128] Although the embodiment can realize the preparation of the nickel-molybdenum-based self-supporting hydrogen evolution electrode, the excessively high temperature can increase the equipment cost.

[0129] Embodiment 17

[0130] The embodiment provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, which comprises the following steps:

[0131] (1) 0.73g of the foamed nickel is placed in a water bath reaction solution to perform a water bath reaction, after the water bath reaction, the water bath reaction precursor is obtained through ultrapure water flushing and drying, and the water bath reaction precursor has a mass of 1.88g;

[0132] The water bath reaction comprises the following steps: being warmed to 90 DEG C and being kept for 6h, being naturally cooled to 50 DEG C, being warmed to 70 DEG C again and being kept for 2h.

[0133] The water bath reaction solution comprises nickel nitrate, ammonium molybdate, urea and water in a molar ratio of 1:5:2:500;

[0134] (2) the water bath reaction precursor is subjected to nitriding treatment in an atmosphere furnace, and the nickel-molybdenum-based self-supporting hydrogen evolution electrode is obtained;

[0135] The nitriding treatment comprises: placing 1.15 g of dicyandiamide powder upstream of the atmosphere furnace, placing the water bath reaction precursor downstream of the atmosphere furnace, vacuumizing and then introducing argon, repeating 5 times to discharge the air in the atmosphere furnace; then introducing Ar and NH3 into the atmosphere furnace at flow rates of 55 sccm and 55 sccm respectively, heating to 700 ℃ at a rate of 5 ℃ / min and maintaining for 3 h, and cooling to room temperature to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0136] Comparative Example 1

[0137] The present comparative example provides a preparation method of a nickel-molybdenum-based self-supporting hydrogen evolution electrode, comprising the following steps:

[0138] (1) 0.73 g of foamed nickel is placed in a water bath reaction solution for water bath reaction, after the water bath reaction is completed, the water bath reaction precursor is obtained by ultrapure water washing and drying, and the weight of the water bath reaction precursor is 1.48 g;

[0139] The water bath reaction comprises heating to 90 ℃ and maintaining for 8 h;

[0140] The water bath reaction solution comprises nickel nitrate, ammonium molybdate, urea and water in a molar ratio of 1:5:2:500;

[0141] (2) The water bath reaction precursor is subjected to nitriding treatment in an atmosphere furnace to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode;

[0142] The nitriding treatment comprises: placing 1.15 g of dicyandiamide powder upstream of the atmosphere furnace, placing the water bath reaction precursor downstream of the atmosphere furnace, vacuumizing and then introducing argon, repeating 5 times to discharge the air in the atmosphere furnace; then introducing Ar and NH3 into the atmosphere furnace at flow rates of 55 sccm and 55 sccm respectively, heating to 700 ℃ at a rate of 5 ℃ / min and maintaining for 3 h, and cooling to room temperature to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode.

[0143] The SEM image of the nickel-molybdenum-based self-supporting hydrogen evolution electrode obtained in the present comparative example is shown in FIG. 1. Figure 2

[0144] Performance test

[0145] The mechanical strength and hydrogen evolution catalytic activity of the nickel-molybdenum-based self-supporting hydrogen evolution electrodes obtained in Examples 1-17 and Comparative Example 1 are tested, and the results are shown in Table 1.

[0146] Table 1

[0147]

[0148]

[0149] ​In summary, the preparation method provided by the application has low cost, does not require complex equipment in the preparation process, can simplify the process flow and shorten the preparation period of the electrode, and can guarantee the electrochemical activity and mechanical strength of the obtained nickel-molybdenum-based self-supporting hydrogen evolution electrode. Specifically, the nanocolumn structure is formed by at least twice heating in the hydrothermal reaction, the process flow is simplified, the preparation period of the electrode is shortened, and the nanocolumn structure has good electrochemical activity and mechanical strength. Through the cooperation of the water bath reaction and the nitriding treatment, the oxygen element in the precursor can be eliminated, the Ni-Mo electronic structure can be regulated, and the catalytic activity and stability of the self-supporting hydrogen evolution electrode are improved.

[0150] The above merely describes specific embodiments of the application, but the protection scope of the application is not limited thereto. It should be understood by those skilled in the art that any changes or replacements within the technical scope disclosed by the application can be easily conceived by those skilled in the art, and all fall within the protection scope and disclosure scope of the application.

Claims

1. A method for preparing a nickel-molybdenum-based self-supporting hydrogen evolution electrode, characterized in that, The preparation method comprises the following steps: The substrate is placed in a water bath reaction solution for water bath reaction, and a water bath reaction precursor is obtained after the water bath reaction; and the water bath reaction precursor is subjected to nitriding treatment to obtain the nickel-molybdenum-based self-supporting hydrogen evolution electrode. The water bath reaction comprises at least two temperature rising processes, and a temperature falling process is performed between two adjacent temperature rising processes.

2. The production method according to claim 1, characterized by, The water bath reaction comprises a first temperature rising process, a first temperature holding process, a temperature falling process, a second temperature rising process and a second temperature holding process performed in sequence. Preferably, the terminal temperature of the first temperature rising process is 80-110°C. Preferably, the time of the first temperature holding process is 1-9h.

3. The production method according to claim 2, characterized by, The terminal temperature of the temperature falling process is 30-70°C.

4. The production method according to claim 2 or 3, characterized by, The terminal temperature of the second temperature rising process is 80-110°C. Preferably, the time of the second temperature holding process is 0.5-4h.

5. The production method according to any one of claims 1 to 4, characterized by, The nitriding treatment is performed using a gaseous nitrogen source and / or a solid nitrogen source. Preferably, the temperature of the nitriding treatment is 400-1000°C. Preferably, the time of the nitriding treatment is 1-5h.

6. The preparation method according to claim 5, characterized in that, When the nitriding treatment is performed using a gaseous nitrogen source, a protective gas and the gaseous nitrogen source are simultaneously introduced. Preferably, the flow ratio of the protective gas to the gaseous nitrogen source is 1:(0.1-10). Preferably, when the nitriding treatment is performed using a solid nitrogen source, the weight ratio of the solid nitrogen source to the water bath reaction load is 1:(0.1-10).

7. The production method according to claim 6, wherein When the nitriding treatment is performed using a solid nitrogen source and a gaseous nitrogen source simultaneously, a protective gas and the gaseous nitrogen source are simultaneously introduced. Preferably, when the nitriding treatment is performed using a solid nitrogen source and a gaseous nitrogen source simultaneously, the flow ratio of the protective gas to the gaseous nitrogen source is 1:(0.1-5), and the weight ratio of the solid nitrogen source to the water bath reaction load is 1:(0.1-5).

8. The method of any one of claims 1-7, wherein, The water bath reaction solution comprises a nickel source, a molybdenum source, a carbon source and a solvent. Preferably, the molar ratio of the nickel source, the molybdenum source, the carbon source and the solvent is 1:(1-10):(0.1-10):(100-10000).

9. A nickel-molybdenum based self-supporting hydrogen evolution electrode, characterized in that, The nickel-molybdenum-based self-supporting hydrogen evolution electrode is prepared by the preparation method of any one of claims 1-8.

10. Use of a self-supporting hydrogen evolution electrode based on nickel-molybdenum as claimed in claim 9, characterized in that, The nickel-molybdenum-based self-supporting hydrogen evolution electrode is used for electrolysis of water to produce hydrogen.

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