An integrated NiSe@Ni3Se2 / NF composite electrode material for electrocatalytic hydrogen evolution electrode and its preparation method

Abstract

The present invention belongs to the field of electrocatalytic hydrogen evolution, and provides an integrated NiSe@Ni3Se2 / NF composite electrode material for an electrocatalytic hydrogen evolution electrode and a preparation method thereof. The integrated NiSe@Ni3Se2 / NF composite electrode material for an electrocatalytic hydrogen evolution electrode prepared by the method of the present invention has the characteristics of a nanosheet interlaced porous structure. This interconnected nanosheet structure is beneficial to electron transfer and transmission, and increases the contact area between the electrode material and the electrolyte. The small lamellar nanosheet interlaced structure can obtain more phase interfaces and active sites, enhance the intrinsic activity of the material, and thus obtain high electrochemistry hydrogen evolution performance.

Description

Technical Field

[0001] The present invention belongs to the field of electrocatalytic hydrogen evolution, and relates to an integrated NiSe@Ni3Se2 / NF composite electrode material for an electrocatalytic hydrogen evolution electrode and a preparation method thereof Background Art

[0002] Energy and environment are two important issues related to the survival and development of human society. As a new type of high-efficiency and pollution-free energy form, hydrogen only generates water after combustion and utilization, which is an effective way to solve the current energy and environmental problems. As a new type of energy conversion technology, the electrolytic water hydrogen production technology can convert electrical energy into chemical energy for storage and rapid utilization, especially when combined with excess electrical energy resources, it has important significance and can effectively realize the development and utilization of clean energy and solve the problem of regional resource shortage. However, the active components of current electrolytic water hydrogen production electrode materials are mainly noble metals such as platinum and ruthenium in the form of single substances or oxides. Although these noble metal catalysts have high electrocatalytic activity and can effectively improve the electrocatalytic hydrogen evolution efficiency, their high prices and scarcity limit the large-scale commercial application of such electrode materials. Therefore, developing a non-noble metal-based hydrogen evolution catalyst with a simple processing method is still one of the important directions in the current application of electrolytic water hydrogen production

[0003] With recent research, transition metal-based composite materials have shown good research progress in the field of electrocatalytic water splitting. Electrochemical hydrogen evolution electrodes based on materials such as transition metal oxides, hydroxides, and selenides have shown good electrocatalytic activity and stability. Among them, two-dimensional transition metal selenides have received extensive attention as hydrogen evolution electrocatalysts due to their good conductivity and electrochemical activity, and have become ideal candidate materials for energy storage and catalysis. Since Se and S belong to the same main group, the chemical properties of selenides and sulfides are similar; however, Se has stronger metallic properties and its conductivity is much higher than that of S. Therefore, most selenides have better conductivity than sulfides. Currently, common methods for preparing transition metal selenides include hydrothermal method, chemical vapor deposition method, plasma-assisted selenization method, and electrodeposition method, etc. However, the preparation process of two-dimensional transition metal selenides is complex and uncontrollable, which greatly restricts their controllable preparation and practical application. Therefore, it is of great significance to directly design and in-situ prepare heterojunction nanosheets with rich electrochemically active centers on a conductive substrate to realize their application in the field of electrocatalytic hydrogen evolution. The present invention uses NiMoO4 nanosheets grown on the surface of three-dimensional conductive nickel foam (NF) as a precursor, and prepares a NiSe@Ni3Se2 / NF nanosheet-type heterostructure through a one-step hydrothermal selenization method, and studies its application in the field of electrocatalytic hydrogen evolution electrodes Summary of the Invention

[0004] The primary object of the present invention is to provide a preparation method of an integrated NiSe@Ni3Se2 / NF composite electrode material for an electrocatalytic hydrogen evolution electrode.

[0005] Another object of the present invention is to provide an integrated NiSe@Ni3Se2 / NF composite electrode material for an electrocatalytic hydrogen evolution electrode.

[0006] The object of the present invention is achieved by the following solutions:

[0007] A preparation method of an integrated NiSe@Ni3Se2 / NF composite electrode material for an electrocatalytic hydrogen evolution electrode, comprising the following steps:

[0008] (1) Mix sodium molybdate hexahydrate, nickel nitrate hexahydrate and water evenly to obtain a precursor solution;

[0009] (2) Mix the precursor solution obtained in step (1) with nickel foam and carry out a hydrothermal reaction. After the reaction, a NiMoO4 / NF precursor is obtained;

[0010] (3) Mix selenium powder with hydrazine hydrate, and then add the obtained mixed solution into a sodium molybdate hexahydrate solution to obtain a precursor solution;

[0011] (4) Mix the precursor solution obtained in step (3) with the NiMoO4 / NF precursor obtained in step (2), put it into a reaction kettle for hydrothermal reaction, and obtain a NiSe@Ni3Se2 / NF composite electrode material.

[0012] The ratio of sodium molybdate hexahydrate, nickel nitrate hexahydrate and water in step (1) is 0.45 - 0.6 g: 0.65 - 1.2 g: 30 mL, preferably 0.5248 g: 0.8640 g: 30 mL;

[0013] Preferably, the nickel foam in step (2) is soaked in an acid solution before use to remove the surface oxide layer, and then washed with water until neutral to obtain treated nickel foam.

[0014] The temperature of the hydrothermal reaction in step (2) is 120 - 180 °C, and the reaction time is 4 - 8 h.

[0015] Preferably, after the hydrothermal reaction in step (2), the obtained NiMoO4 / NF precursor is washed and dried.

[0016] The mass - volume ratio of selenium powder to hydrazine hydrate in step (3) is 0.5 - 4 g: 1 mL.

[0017] The concentration of the sodium molybdate hexahydrate aqueous solution in step (3) is 0.5 - 3 g / mL.

[0018] The volume ratio of the mixed solution described in step (3) to the sodium molybdate hexahydrate solution is 1:20 - 40.

[0019] The temperature of the hydrothermal reaction described in step (4) is 200 - 250 °C, and the reaction time is 6 - 24 h.

[0020] An integrated NiSe@Ni3Se2 / NF composite electrode material for electrocatalytic hydrogen evolution electrodes is prepared by the above method. The composite electrode material includes a nickel foam substrate and a NiSe@Ni3Se2 / NF nanosheet heterostructure.

[0021] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0022] (1) The integrated NiSe@Ni3Se2 / NF composite electrode material for electrocatalytic hydrogen evolution electrodes prepared by the method of the present invention is composed of two phases, NiSe and Ni3Se2. It not only has the high conductivity characteristics of transition metal selenides, but also has a two-phase interface heterostructure, which is conducive to charge transfer and active site distribution.

[0023] (2) The integrated NiSe@Ni3Se2 / NF composite electrode material for electrocatalytic hydrogen evolution electrodes prepared by the method of the present invention has a nanosheet interlaced porous structure. This interconnected nanosheet structure is conducive to electron transfer and transmission, and increases the contact area between the electrode material and the electrolyte. The small-layer nanosheet interlaced structure can obtain more phase interfaces and active sites, enhance the intrinsic activity of the material, and thus obtain high electrochemically hydrogen evolution performance.

[0024] (3) The integrated NiSe@Ni3Se2 / NF composite electrode material for electrocatalytic hydrogen evolution electrodes prepared by the method of the present invention can obtain excellent electrochemical stability due to the small-layer nanosheet interlaced structure and abundant micropores, and can maintain stable performance during long-term hydrogen evolution reactions.

[0025] (4) The present invention adopts a hydrothermal synthesis method based on a template structure, which is simple in operation, low in cost, and suitable for large-scale production.

[0026] (5) When the heterostructure NiSe@Ni3Se2 / NF composite electrode material prepared by the present invention is used for electrocatalytic hydrogen evolution reaction, the overpotential required to reach a current density of 20 mA·cm -2 is only 184 - 211 mV, and the Tafel slope is 167 - 180 mV·dec -1 , and it has good electrochemically hydrogen evolution catalytic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is the XRD pattern of the samples in Example 1 and Example 2;

[0028] Figure 2 SEM image of the sample in Example 1;

[0029] Figure 3 SEM image of the sample in Example 2;

[0030] Figure 4 LSV curves of the electrochemically hydrogen evolution process of Example 1 and Example 2;

[0031] Figure 5 Tafel slopes of the electrochemically hydrogen evolution process of Example 1 and Example 2;

[0032] Figure 6 Long-term cycling stability curve of the sample in Example 2; Detailed implementation manners

[0033] The present invention will be further described in detail below in conjunction with examples and drawings, but the implementation manners of the present invention are not limited thereto.

[0034] The reagents used in the examples can be obtained conventionally from the market without special instructions.

[0035] Example 1

[0036] (1) Cut nickel foam into pieces of 2*2 cm in size, soak it in 1 mol·L-1 hydrochloric acid for 15 min to remove the surface oxide layer, and then wash it with deionized water until neutral to obtain the treated nickel foam.

[0037] (2) Add 0.5248 g of sodium molybdate hexahydrate and 0.8640 g of nickel nitrate hexahydrate to 30 mL of deionized water and mix and dissolve them, and stir for 15 min to obtain a uniform precursor solution.

[0038] (3) Pour the above precursor solution into a reaction kettle, put the treated nickel foam in step (1) into the reaction kettle, put the reaction kettle into a blast drying oven, react at 150 °C for 6 h, cool to room temperature after the reaction, collect the nickel foam loaded with the product, wash it, and dry it at 50 °C for 12 h to obtain the NiMoO4 / NF precursor.

[0039] (4) At room temperature, mix 0.0200 g of selenium powder with 1 mL of hydrazine hydrate (98% concentration), stir for 5 min and then let it stand for 24 h to obtain a dark red solution. Add the mixed solution to 30 mL of an aqueous solution of deionized water containing 0.0400 g of sodium molybdate hexahydrate to obtain a precursor solution.

[0040] (5) Pour the precursor solution obtained in step (4) into a reaction kettle, put the NiMoO4 / NF precursor obtained in step (3) into the reaction kettle, place the reaction kettle in a forced air drying oven, react at 220 °C for 10 h, cool to room temperature after the reaction, collect the nickel foam loaded with the product, wash it, and dry it at 50 °C for 12 h to obtain the NiSe@Ni3Se2 / NF composite electrode material.

[0041] Example 2

[0042] (1) Cut the nickel foam into pieces of 2*2 cm in size, soak it in 1 mol·L-1 hydrochloric acid for 15 min to remove the surface oxide layer, and then wash it with deionized water until neutral to obtain the treated nickel foam.

[0043] (2) Add 0.5248 g of sodium molybdate hexahydrate and 0.8640 g of nickel nitrate hexahydrate to 30 mL of deionized water, mix and dissolve, and stir for 15 min to obtain a uniform precursor solution.

[0044] (3) Pour the above precursor solution into a reaction kettle, put the treated nickel foam in step (1) into the reaction kettle, place the reaction kettle in a forced air drying oven, react at 150 °C for 6 h, cool to room temperature after the reaction, collect the nickel foam loaded with the product, wash it, and dry it at 50 °C for 12 h to obtain the NiMoO4 / NF precursor.

[0045] (4) At room temperature, mix 0.0400 g of selenium powder with 1 mL of hydrazine hydrate (98% concentration), stir for 5 min and then let it stand for 24 h to obtain a dark red solution. Add the mixed solution to 30 mL of an aqueous solution of deionized water containing 0.0400 g of sodium molybdate hexahydrate to obtain a precursor solution.

[0046] (5) Pour the precursor solution obtained in step (4) into a reaction kettle, put the NiMoO4 / NF precursor obtained in step (3) into the reaction kettle, place the reaction kettle in a forced air drying oven, react at 220 °C for 10 h, cool to room temperature after the reaction, collect the nickel foam loaded with the product, wash it, and dry it at 50 °C for 12 h to obtain the NiSe@Ni3Se 2 / NF composite electrode material.

[0047] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. Preparation method of an integrated NiSe@Ni3Se2 / NF composite electrode material for electrocatalytic hydrogen evolution electrode, characterized in that It includes the following steps: (1) Mix sodium molybdate hexahydrate, nickel nitrate hexahydrate and water evenly to obtain a precursor solution; (2) Mix the precursor solution obtained in step (1) with nickel foam and conduct a hydrothermal reaction. After the reaction, a NiMoO4 / NF precursor is obtained; (3) Mix selenium powder with hydrazine hydrate, and then add the obtained mixed solution into a sodium molybdate hexahydrate solution to obtain a precursor solution; (4) Mix the precursor solution obtained in step (3) with the NiMoO4 / NF precursor obtained in step (2) and conduct a hydrothermal reaction in a reaction kettle to obtain a NiSe@Ni3Se2 / NF composite electrode material; The temperature of the hydrothermal reaction described in step (2) is 120~180 °C, and the reaction time is 4~8 h; The temperature of the hydrothermal reaction described in step (4) is 200~250 °C, and the reaction time is 6~24 h.

2. The method according to claim 1, wherein: The ratio of sodium molybdate hexahydrate, nickel nitrate hexahydrate and water described in step (1) is 0.45~0.6 g: 0.65~1.2 g: 30 mL.

3. The method according to claim 1, characterized in that: The ratio of sodium molybdate hexahydrate, nickel nitrate hexahydrate and water described in step (1) is 0.5248 g: 0.8640 g: 30 mL.

4. The method according to claim 1, wherein: The mass-volume ratio of selenium powder to hydrazine hydrate described in step (3) is 0.5~4 g: 1 mL.

5. The method according to claim 1, characterized in that: The concentration of the sodium molybdate hexahydrate aqueous solution described in step (3) is 0.5~3 g / mL.

6. The method according to claim 1, wherein: The volume ratio of the mixed solution to the sodium molybdate hexahydrate solution described in step (3) is 1:20~40.

7. The method according to claim 1, wherein: After the hydrothermal reaction described in step (2) ends, wash and dry the obtained NiMoO4 / NF precursor.

8. An integrated NiSe@Ni3Se2 / NF composite electrode material for an electrocatalytic hydrogen evolution electrode, which is prepared by the method according to any one of claims 1~7.

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