Method for preparing carbon-coated nickel-molybdenum nitride material through nitrogen-containing organic solvent steam modification

Abstract

The invention provides a method for preparing a carbon-coated nickel-molybdenum nitride material through nitrogen-containing organic solvent steam modification, which is characterized by comprising the following steps of: loading a nickel-molybdenum composite oxide precursor layer on a nickel base through a liquid phase deposition method, heating the material subjected to liquid phase deposition to 400-800 DEG C in an argon atmosphere, and carrying out heat preservation for 2-3 hours, so as to obtain the carbon-coated nickel-molybdenum nitride material. Then inert gas is used as carrier gas to carry nitrogen-containing organic matter solvent volatile steam at a certain temperature to enter a tubular furnace, carbon and nitrogen species generated by decomposition of the organic matter solvent steam are used for reduction, nitrogen doping and carbon coating on the nickel molybdenum oxide precursor layer growing on the nickel base under the high-temperature condition, and the carbon-coated nickel molybdenum nitride material is prepared. The method provided by the invention is simple and easy to implement, and the prepared cathode material has excellent electrocatalytic hydrogen evolution activity and tolerance in alkaline electrolyzed water.

Description

Technical Field

[0001] The present invention belongs to the field of hydrogen energy, and particularly relates to a method for preparing a highly active and long-life hydrogen evolution cathode by modifying with nitrogen-containing organic solvent vapor. Background Art

[0002] Electrolysis of water is the main way to obtain green hydrogen energy. Electrolysis of water mainly includes anodic oxygen evolution reaction and cathodic hydrogen evolution reaction. Noble metal Pt and its alloys are the hydrogen evolution cathode catalysts with the best catalytic activity, but noble metal Pt is expensive and scarce in production. In recent years, transition metal carbides and nitrides have been widely studied for electrocatalytic hydrogen evolution reaction. On the one hand, carbon and nitrogen can effectively regulate the electronic structure of transition metals and thus regulate the adsorption energy of active hydrogen. On the other hand, compared with oxides, nitrides or carbides have advantages such as good electrical conductivity and acid and alkali corrosion resistance.

[0003] Nickel molybdenum nitride materials have been highly favored in the research of electrolytic water hydrogen production catalysts. They are often prepared by high-temperature reduction and nitridation reactions of nickel molybdenum composite oxides in an NH3 atmosphere, or by nitridation through pyrolysis of nitrogen-containing organic solids. The literature (Research on the Design and Preparation of Nickel-based Self-Supported Electrodes and Their Performance in Electro-Catalytic Water Splitting, Dissertation) reported a method for preparing nickel molybdenum nitride composite materials by nitriding one-dimensional arrays of nickel molybdenum oxides in-situ grown on a hydrothermal foam nickel substrate using NH3 at an appropriate temperature. It has good electrocatalytic hydrogen evolution performance in alkaline electrolytic water hydrogen production and has good stability. However, NH3 used for nitriding the nickel molybdenum oxides of the material is a toxic and flammable gas and is prone to explosion at high temperatures, which is not conducive to industrial use. The literature (Study on the Preparation of Bimetallic Nitride NiMoN Hydrogen Evolution Catalyst and Its Performance in Electrolysizing Seawater for Hydrogen Evolution) reported a series of NiMO x N@NC catalysts prepared by using dicyandiamide as a nitrogen source through high-temperature nitridation - temperature-programmed method, which have good electrocatalytic activity in alkaline solution. However, using pyrolysis of solid nitrogen-containing organic matter to form volatile nitrogen-containing and carbon-containing gases has the disadvantages that the gas components and concentrations are not easy to control, and due to the difference in the pyrolysis temperature of solid nitrogen-containing organic matter and the nitridation temperature of nickel molybdenum oxides, it results in low nitridation and carbon coating efficiency. Summary of the Invention

[0004] In view of the above, the present invention provides a method for preparing carbon-coated nickel molybdenum nitride materials by modifying with nitrogen-containing organic solvent vapor. This method uses an inert gas to carry the vapor of a nitrogen-containing organic solvent as a carbon and nitrogen source, and under high-temperature conditions, the carbon and nitrogen species generated by decomposing the nitrogen-containing organic solvent vapor are used to reduce, nitrogen-dope and carbon-coat the nickel molybdenum composite oxide precursor layer on the nickel-based substrate, preparing carbon-coated nickel molybdenum nitride materials with excellent electrocatalytic hydrogen evolution activity and stability. This method is simple, easy to operate, safe and reliable, and has high industrial application value.

[0005] The specific operation steps of the method for preparing carbon-coated nickel molybdenum nitride material by modifying with nitrogen-containing organic solvent vapor in the present invention are as follows:

[0006] (1) The nickel metal mesh is pretreated by degreasing and pickling. The nickel metal mesh used in the present invention is a common commercial nickel mesh. The cut nickel metal mesh is placed in an acetone solution for ultrasonic degreasing treatment. The ultrasonic time is 2 - 60 min, and the temperature is from room temperature to 80 °C. The purpose is to remove the oil stain on the surface of the nickel metal mesh. Subsequently, ultrasonic pickling treatment is carried out in a 0.5 - 5 mol / L HCl solution. The ultrasonic time is 5 - 60 min, and the temperature is from room temperature to 50 °C. The purpose is to remove the oxide film on the surface of the nickel metal mesh. Finally, it is washed clean with ultrapure water and dried for later use.

[0007] (2) The pretreated nickel metal mesh is subjected to liquid-phase deposition (hydrothermal) treatment. A mixed solution is prepared with one of nickel sulfate, nickel chloride, nickel acetate, and nickel nitrate as the nickel salt and one of potassium molybdate, ammonium molybdate, and sodium molybdate as the molybdate. Under the conditions of a reaction temperature of 100 - 190 °C and a reaction time of 2 - 10 h, the pretreated nickel metal mesh is subjected to liquid-phase deposition treatment to grow a nickel molybdenum composite oxide precursor layer on the surface of the nickel metal mesh. Then, the nickel metal mesh material loaded with the nickel molybdenum composite oxide precursor layer is treated clean with ultrapure water and dried in an oven at a temperature of 40 - 120 °C for a drying time of 2 - 12 h.

[0008] (3) The precursor layer of the nickel metal mesh after liquid-phase deposition treatment is subjected to reduction, nitridation, and carbonization treatment. The nickel metal mesh material loaded with nickel molybdenum composite oxide dried in step (2) is placed in a tubular furnace. Argon or nitrogen is introduced into the tubular furnace as the carrier gas, and then the tubular furnace is started and heated to a high temperature. The high temperature range is 400 - 800 °C. Then, the carrier gas valve is switched. The carrier gas is pre-passed through an organic solvent containing a nitrogen component, and the nitrogen-containing organic solvent vapor carried by the carrier gas enters the high-temperature tubular furnace as the carbon and nitrogen source. At high temperature, the nickel molybdenum composite oxide precursor layer on the nickel mesh undergoes reduction, nitrogen doping, and carbon deposition reactions. After the high-temperature reaction for 2 - 60 min, the carrier gas valve is switched again, and the carrier gas does not pass through the organic solvent and is directly introduced into the tubular furnace to cool the material to room temperature to obtain the carbon-coated nickel molybdenum nitride material. The nitrogen-containing organic solvent used in the present invention is one or a mixture of two of N,N-dimethylformamide, acetonitrile, N-methylpyrrole, pyridine, and pyrrole.

[0009] The advantages of the technical solution of the present invention are that the organic solvent vapor of the nitrogen-containing organic matter carried by the carrier gas (inert gas) is used to carry out reduction and carbon and nitrogen treatment on the nickel molybdenum composite oxide of the nickel metal mesh precursor layer at high temperature. This method is safe, reliable, simple, easy to implement, controllable, and efficient, and the carbon-coated nickel molybdenum nitride material prepared has a more uniform carbon coating. There is no need to use toxic and harmful NH3 plus additional CH4 gas for nitridation and carbon coating.

[0010] The advantages of the technical solution of the present invention are that the prepared carbon-coated nickel molybdenum nitride material has excellent electrocatalytic hydrogen evolution activity under alkaline conditions, comparable to that of commercial Pt / C; at the same time, the carbon-coated nickel molybdenum nitride material treated with carbon and nitrogen has higher stability and tolerance than the nickel molybdenum nitride material. Description of the Drawings

[0011] Figure 1 It is an XRD pattern of the nickel-based carbon-coated nickel molybdenum nitride material prepared by the present invention.

[0012] Figure 2 It is an LSV test pattern of the nickel-based carbon-coated nickel molybdenum nitride material, nickel-based material, nickel-based material after liquid-phase deposition treatment, and commercial Pt / C material prepared by the present invention in 1M KOH. Specific Embodiment Method

[0013] Hereinafter, the method for preparing a carbon-coated nickel molybdenum nitride material by modifying with a nitrogen-containing organic solvent vapor of the present invention will be more clearly described in conjunction with the embodiments.

[0014] Example 1

[0015] 1. Surface pretreatment of the nickel metal mesh: Cut the nickel metal mesh of 4 cm * 5 cm and put it into an acetone solution for degreasing by ultrasonic treatment for 5 minutes to remove the oil stain on the nickel-based surface; after the degreasing treatment, rinse the nickel mesh material with ultrapure water and then put it into a 6 mol / L HCl solution for pickling by ultrasonic treatment for 12 minutes to remove the oxide film on the nickel mesh surface and etch the nickel-based material; after the pretreatment, rinse the material with ultrapure water and dry it for later use.

[0016] 2. Liquid-phase deposition treatment of the nickel metal mesh material pretreated in step 1: Put the pretreated nickel metal mesh material into a mixed solution of 43 mM nickel nitrate and 9 mM ammonium molybdate, and carry out liquid-phase deposition treatment on the pretreated nickel metal mesh under the conditions of a liquid-phase deposition temperature of 140 °C and a liquid-phase deposition time of 6 hours to prepare a nickel molybdenum composite oxide precursor layer on the nickel-based. After the liquid-phase deposition treatment, rinse with ultrapure water and dry at 100 °C for 6 hours for later carbon and nitrogen treatment.

[0017] 3. Subject the nickel metal mesh material after the liquid-phase deposition treatment in Step 2 to carbonitriding treatment. Take the nickel metal mesh material after the liquid-phase deposition treatment and place it in a tubular furnace under an argon atmosphere. Heat it to 650 °C at a heating rate of 5 °C / min. Then switch the carrier gas valve. First, pass argon into the acetonitrile solution so that it carries the organic solvent vapor into the tubular furnace for high-temperature reaction, and perform reduction, nitridation, and carbonization treatments on the nickel molybdenum composite oxide precursor layer on the nickel metal mesh material after the liquid-phase deposition treatment. After 10 min, switch the carrier gas valve again and directly pass argon into the tubular furnace to cool the material to room temperature. Take out the sample to obtain the carbon-coated nickel molybdenum nitride material 1.

[0018] Appendix Figure 1 This is the XRD pattern of the carbon-coated nickel molybdenum nitride material prepared in Example 1. In the figure, there are peaks of NiMoO4, Ni 0.2 Mo 0.8 N, Ni, and C, which prove the presence of elements C, N, O, Ni, and Mo in the material.

[0019] Example 2

[0020] 1. Perform surface pretreatment on the nickel metal mesh material. Put the cut nickel metal mesh material of 4 cm * 5 cm into acetone solution for degreasing by ultrasonic treatment for 30 min, the purpose of which is to remove the oil stain on the nickel base surface; after the degreasing treatment, rinse the nickel metal mesh material with ultrapure water and then put it into 1 mol / L HCl solution for pickling by ultrasonic treatment for 60 min, the purpose of which is to remove the oxide film on the nickel metal mesh material surface and etch the nickel base material; then rinse the pretreated nickel metal mesh material with ultrapure water, dry it for later use.

[0021] 2. Perform liquid-phase deposition treatment on the nickel metal mesh material pretreated in Step 1. Take the pretreated nickel metal mesh material and put it into a mixed solution of 24 mM nickel nitrate and 8 mM ammonium molybdate. Under the conditions of a liquid-phase deposition temperature of 180 °C and a liquid-phase deposition time of 4 h, perform liquid-phase deposition treatment on the pretreated nickel metal mesh material to prepare a nickel molybdenum composite oxide precursor layer on the nickel metal mesh material. After the liquid-phase deposition treatment, rinse the nickel metal mesh material with ultrapure water and dry it at 80 °C for 8 h for subsequent carbonitriding treatment.

[0022] 3. Subject the nickel metal mesh material after the liquid-phase deposition treatment in Step 2 to carbonitridation treatment. Place the nickel metal mesh material after the liquid-phase deposition treatment in a tubular furnace under an argon atmosphere, heat it to 500 °C at a heating rate of 4 °C / min, then switch the carrier gas valve. First, pass argon into an acetonitrile solution to make it carry organic solvent vapor into the tubular furnace for high-temperature reaction, and perform reduction, nitridation, and carbonization treatments on the nickel metal mesh material after the liquid-phase deposition treatment. After 15 minutes, switch the carrier gas valve again, directly pass argon into the tubular furnace, cool the material to room temperature, and take out the sample to obtain the carbon-coated nickel molybdenum nitride material 2.

[0023] Example 3

[0024] 1. Perform surface pretreatment on the nickel metal mesh material. Place the cut nickel metal mesh material of 10 cm * 10 cm into an acetone solution for degreasing by ultrasonic treatment for 25 minutes, with the aim of removing the oil stain on the nickel base surface; after the degreasing treatment, rinse the nickel metal mesh material with ultrapure water and then place it in a 3 mol / L HCl solution for ultrasonic treatment for 25 minutes, with the aim of removing the oxide film on the surface of the nickel metal mesh material and etching the nickel-based material; rinse the pretreated material with ultrapure water, dry it, and set it aside for later use.

[0025] 2. Perform liquid-phase deposition treatment on the nickel metal mesh material pretreated in Step 1. Place the pretreated nickel metal mesh material into a mixed solution of 38 mM nickel nitrate and 14 mM ammonium molybdate, and perform liquid-phase deposition treatment on the pretreated nickel metal mesh under the conditions of a liquid-phase deposition temperature of 160 °C and a liquid-phase deposition time of 5 h to prepare a nickel molybdenum composite oxide precursor layer on the nickel metal mesh material. After the hydrothermal treatment, rinse the nickel metal mesh material with ultrapure water and dry it at 70 °C for 10 h, and dry it for subsequent carbonitridation treatment.

[0026] 3. Subject the nickel metal mesh material after the liquid-phase deposition treatment in Step 2 to carbonitridation treatment. Place the nickel metal mesh material after the liquid-phase deposition treatment in a tubular furnace under an argon atmosphere, heat it to 700 °C at a heating rate of 8 °C / min, then switch the carrier gas valve. First, pass argon into an acetonitrile solution to make it carry organic solvent vapor into the tubular furnace for high-temperature reaction, and perform reduction, nitridation, and carbonization treatments on the nickel molybdenum composite oxide precursor layer on the nickel metal mesh material after the liquid-phase deposition treatment. After 5 minutes, switch the carrier gas valve again, directly pass argon into the tubular furnace, cool the material to room temperature, and take out the sample to obtain the carbon-coated nickel molybdenum nitride material 3.

[0027] Perform linear sweep voltammetry tests on the carbon-coated nickel molybdenum nitride materials prepared in Examples 1, 2, and 3, the nickel metal mesh materials, the nickel metal mesh materials after the liquid-phase deposition treatment, and the Pt / C electrode materials in 1 M KOH solution, and compare their electrocatalytic hydrogen evolution activities. Attachment Figure 2Linear sweep voltammetry graph of the electrocatalytic hydrogen evolution activity of the cathode material. The test conditions are as follows: 1 M KOH solution; solution temperature 27 °C; and no IR compensation for the test polarization curve. The linear sweep voltammetry test results show that the carbon-coated nickel molybdenum nitride material prepared by the modification with nitrogen-containing organic solvent vapor in the present invention has high electrocatalytic hydrogen evolution activity in 1 M KOH solution and has electrocatalytic hydrogen evolution activity similar to that of commercial Pt / C. It is far superior to commercial nickel metal mesh and nickel metal mesh materials after liquid phase deposition treatment.

Claims

1. A method for preparing carbon-coated nickel molybdenum nitride material by modifying with nitrogen-containing organic solvent vapor, characterized in that: A nickel molybdenum composite oxide precursor layer is loaded on a nickel metal mesh by a liquid phase deposition method. Then, under high temperature conditions by a gas phase method, carbon and nitrogen species generated by decomposing a nitrogen-containing organic solvent vapor are used to reduce, nitrogen dope, and carbon coat the nickel molybdenum composite oxide precursor layer loaded on the nickel-based material by the liquid phase deposition method, thereby preparing a carbon-coated nickel molybdenum nitride material. The specific preparation process is as follows: (1) Using one of nickel sulfate, nickel chloride, nickel acetate, and nickel nitrate as a nickel salt, and using one of potassium molybdate, ammonium molybdate, and sodium molybdate as a molybdate to prepare a mixed solution, and loading a nickel molybdenum composite oxide precursor layer on the nickel metal mesh by a liquid phase deposition method; (2) Washing the nickel metal mesh material loaded with the nickel molybdenum composite oxide precursor layer and then placing it in an oven for drying; (3) Placing the dried nickel mesh material loaded with the nickel molybdenum composite oxide precursor layer in a tubular furnace, introducing argon or nitrogen as a carrier gas into the tubular furnace, starting to heat the tubular furnace to a high temperature, and the high temperature range is 400 - 800 °C; then switching the valve between the carrier gas and the tubular furnace, first introducing the carrier gas into the carbon and nitrogen organic solvent to make it carry the vapor volatilized from the organic solvent, and then entering the high temperature tubular furnace to react with the nickel molybdenum oxide on the nickel-based material, so that the nickel molybdenum oxide precursor layer on the nickel metal mesh undergoes reduction, nitrogen doping, and carbon deposition reactions at high temperature to obtain a carbon-coated nickel molybdenum nitride material.

2. The method for preparing a carbon-coated nickel molybdenum nitride material by modifying with nitrogen-containing organic solvent vapor as claimed in claim 1, wherein The concentration range of the nickel salt described in step (1) is 10 - 200 mM, and the molar ratio of nickel and molybdenum elements in the nickel salt and molybdenum salt is 1 - 5:

1.

3. The method for preparing a carbon-coated nickel molybdenum nitride material by modifying with nitrogen-containing organic solvent vapor as described in claim 1, wherein The hydrothermal temperature described in step (1) is 100 - 190 °C, and the hydrothermal time is 2 - 10 h.

4. The method for preparing a carbon-coated nickel molybdenum nitride material by modifying with nitrogen-containing organic solvent vapor as claimed in claim 1, wherein The nitrogen-containing organic solvent described in step (3) is one or a mixture of two of N,N-dimethylformamide, acetonitrile, N-methylpyrrole, pyridine, and pyrrole.

5. The method for preparing a carbon-coated nickel molybdenum nitride material by modifying with nitrogen-containing organic solvent vapor as claimed in claim 1, wherein The high temperature reaction time for reducing, carbon doping, and carbon depositing the nickel molybdenum composite oxide precursor layer on the nickel metal mesh at high temperature described in step (3) is 2 - 60 min.

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