阅读说明：本技术 具有微纳双级孔和高结构稳定性的NiSe2-CoSe2/CFs复合材料及其制备 (NiSe with micro-nano double-stage holes and high structural stability2-CoSe2/CFs composite material and preparation thereof ) 是由 张龙 鲁媛媛 杨森 于 2021-06-22 设计创作，主要内容包括：本发明公开了一种具有微纳双级孔和高结构稳定性的NiSe-(2)-CoSe-(2)/CFs复合材料及其制备,该复合材料包括微米级多孔碳纤维基体以及负载于碳纤维基体上的纳米泡沫状NiSe-(2)-CoSe-(2)材料；Ni与Co的原子比为(1.6～2.5):1。利用水热法和化学气相沉积法制备碳纤维负载NiSe-(2)-CoSe-(2)复合材料,在H-(2)+N-(2)气氛下对其进行热处理即得。本发明产品具有优异的力学稳定性；将其直接应用于电解水制氢的阴极电极可以缓解工业大电流长时间服役条件下气体冲击对电极活性相结构稳定性的破坏作用,显著提高电极的机械稳定性,从而延长电极的使用寿命,降低电解水成本。(The invention discloses NiSe with micro-nano double-stage holes and high structural stability 2 ‑CoSe 2 The composite material comprises a micron-sized porous carbon fiber substrate and nano-foam NiSe loaded on the carbon fiber substrate 2 ‑CoSe 2 A material; the atomic ratio of Ni to Co is (1.6-2.5): 1. Method for preparing carbon fiber loaded NiSe by using hydrothermal method and chemical vapor deposition method 2 ‑CoSe 2 Composite material of formula (I) in 2 +N 2 Heat treating under atmosphere to obtain. The product of the invention has excellent mechanical stability; the cathode electrode directly applied to the hydrogen production by water electrolysis can relieve the damage effect of gas impact on the stability of an electrode active phase structure under the long-time service condition of industrial heavy current, and obviously improve the mechanical stability of the electrode, thereby prolonging the service life of the electrode and reducing the water electrolysis cost.)

1. NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂a/CFs composite, comprising: carbon fiber substrate with micron-scale porous structure and nano-scale foamed NiSe loaded on carbon fiber substrate₂-CoSe₂A material; the NiSe₂-CoSe₂the/CFs composite has both micro-and nanopores.

2. The NiSe of claim 1₂-CoSe₂the/CFs composite material is characterized in that the size of the micron-sized pores is 10-20 microns, and the size of the nanometer-sized pores is 100 nm-1 micron; the diameter of a single fiber of the carbon fiber matrix is 8-15 mu m; the atomic ratio of Ni to Co in the composite material is (1.6-2.5) to 1.

3. NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂the/CFs composite material is characterized by comprising the following raw materials: porous carbon fiber, nickel source, cobalt source, additive,Selenizing liquid and deionized water; the diameter of a single fiber of the porous carbon fiber is 8-15 mu m.

4. The NiSe of claim 3₂-CoSe₂the/CFs composite material is characterized in that the atomic ratio of Ni to Co in the nickel source and the cobalt source is (1.6-2.5) to 1.

5. The NiSe of claim 3₂-CoSe₂the/CFs composite material is characterized in that the additive is glycol or glycerol.

6. The NiSe of claim 3₂-CoSe₂the/CFs composite material is characterized in that the selenizing liquid is obtained by dissolving 0.1-0.6 g of selenium powder in 5-20 mL of hydrazine hydrate and standing.

7. NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂The preparation method of the/CFs composite material is characterized by comprising the following steps:

step 1, stirring porous carbon fibers, a nickel source, a cobalt source and deionized water, and uniformly mixing to obtain a precursor solution; carrying out hydrothermal growth on the precursor solution in a high-pressure kettle to obtain a primary carbon fiber-loaded basic nickel cobalt carbonate nanowire product; cleaning the primary carbon fiber-loaded basic nickel cobalt carbonate nanowire product to obtain a precursor of the carbon fiber-loaded basic nickel cobalt carbonate nanowire; wherein the atomic ratio of Ni to Co in the carbon fiber loaded basic nickel cobalt carbonate nanowire precursor is (1.6-2.5) to 1;

step 2, preparing a selenizing solution, respectively adding a precursor of the carbon fiber-loaded basic nickel cobalt carbonate nanowire, an additive and the selenizing solution into deionized water, uniformly mixing, and then carrying out hydrothermal reaction to obtain a carbon fiber-loaded Ni-Co-Se ternary nanostructure primary product; cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product to obtain a carbon fiber loaded Ni-Co-Se ternary nanostructure;

step 3, carrying out Ni-Co-Se III on the carbon fiberMeta-nanostructures in H₂And N₂Carrying out heat treatment in mixed atmosphere to obtain NiSe with micro-nano double-level holes₂-CoSe₂a/CFs composite material.

8. The preparation method according to claim 7, wherein in the step 1, the temperature of the hydrothermal growth is 110-130 ℃ and the time is 8-10 h; in the step 2, the temperature of the hydrothermal reaction is 180-200 ℃, and the time is 6-10 hours.

9. The method according to claim 7, wherein in step 3, H is₂And N₂The volume ratio of (A) is 1/31-1/21; the temperature of the heat treatment is 430-480 ℃, the heat preservation time is 50-70 min, and the temperature rise rate is 5-12 ℃/min.

10. NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂The application of the/CFs composite material in the field of hydrogen production by electrolyzing water.

Technical Field

The invention relates toThe technical field of hydrogen production by water electrolysis, in particular to NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂a/CFs composite material and preparation thereof.

Background

The demand for energy is increasing due to the rapid advance of industrialization, fossil fuels mainly including petroleum and coal are almost consumed as conventional energy sources, and the use of fossil fuels in large quantities leads to CO₂The emission amount seriously exceeds the standard and aggravates various environmental pollution problems such as global temperature rise, haze and the like. Hydrogen energy has received increasing attention from the industry due to its advantages of zero carbon, high energy density, storage, and ease of transportation. The water electrolysis hydrogen production technology can decompose the most abundant water resources on the earth into hydrogen, and the whole process has no harm to the environment, can be circulated and has huge application prospect.

Transition Metal Selenides (TMDs) are substances with excellent hydrogen production activity by electrolyzing water, and compared with noble metals, the TMDs have very high market value due to the characteristic of low price. The selenide formed by combining transition metal elements Co, Ni and Se has two structures of pyrite and white iron ore, wherein the pyrite structure belongs to a typical cubic phase structure, the white iron ore structure belongs to an orthogonal phase structure, and the pyrite structure TMDS has more excellent intrinsic water electrolysis hydrogen production activity than the white iron ore structure and has the characteristics of nano-scale and porous M (Co, Ni) -Se₂Shows very rich active sites and has obvious advantages in the aspect of replacing precious metal materials to reduce the cost of electrolyzed water. In the presence of M (Co, Ni) -Se₂In the process of assembling the nano material into the electrode which can be directly applied in a large scale, how to coordinate the maximization of the specific surface area, the super-air-permeability and the high mechanical structure stability becomes a pain point in further promoting the industrialization process of the nano material.

M (Co, Ni) -Se in nano-particle shape₂The material inevitably has a particle accumulation phenomenon in the industrial preparation coating process of the electrolytic water cathode, which can lead to the great reduction of the number of active sites of the electrode, and the use of the binder can further lead to the loss of the active sites. The three-dimensional integrated electrode material is designed byThe ideal solution of the industrial electrode is a novel structure which takes a porous conductive matrix as a carrier and carries an active material in situ, and the novel structure has obvious inhibiting effect on the reduction effect of the number of active sites caused by particle accumulation and binder addition. However, the literature reports M (Co, Ni) -Se supported₂M (Co, Ni) -Se in the three-dimensional integrated electrode material₂The active phase is mainly a nanowire or nanosheet array structure, when the structure is used for high-current long-time electrolytic water production, due to the fact that exchange of liquid phase and gas phase substances on the surface of an electrode is severe, the electrode is in severe service conditions such as high temperature and strong corrosion, and under the long-time impact of high-flux gas generated by analysis, M (Co, Ni) -Se in the form of nanowire or nanosheet array₂The active phase is easy to generate structural instability, so that the service life of the electrode is short.

Disclosure of Invention

To satisfy the industrialization of M (Co, Ni) -Se₂The invention provides NiSe with micro-nano double-level holes and high structural stability based on the requirements of hydrogen production electrodes by water electrolysis on the aspects of specific surface area, gas permeability and mechanical structural stability₂-CoSe₂a/CFs composite material having excellent mechanical stability and a process for preparing the same₂-CoSe₂the/CFs composite material applied to the electrode material for producing hydrogen by electrolyzing water can powerfully relieve the destructive effect of gas impact on the stability of the electrode active phase structure under the long-time service condition of industrial large current, and obviously improve the mechanical stability of the electrode, thereby prolonging the service life of the electrode.

The invention is realized by adopting the following technical scheme:

(I) NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂a/CFs composite comprising: carbon fiber matrixes (CFs) with micron-scale porous structures and nano-scale foamed NiSe loaded on the carbon fiber matrixes₂-CoSe₂A material; the NiSe₂-CoSe₂the/CFs composite has both micro-and nanopores.

Furthermore, the size of the micron-sized pores is 10-20 μm, and the size of the nanometer-sized pores is 100 nm-1 μm; the diameter of a single fiber of the carbon fiber matrix is 8-15 mu m, and the atomic ratio of Ni to Co is (1.6-2.5): 1.

further, the NiSe₂-CoSe₂the/CFs composite material comprises the following raw materials: porous carbon fiber, a nickel source, a cobalt source, an additive, a selenizing liquid and deionized water.

Furthermore, the atomic ratio of Ni to Co in the nickel source and the cobalt source is (1.6-2.5): 1.

still further, the additive is one or more of ethylene glycol and glycerol.

Furthermore, the selenizing solution is prepared by dissolving 0.1-0.6 g of selenium powder in 5-20 mL of hydrazine hydrate and standing.

Further, the nickel source is Ni (NO)₃)₂And NiSO₄The cobalt source is Co (NO)₃)₂And CoSO₄One or more of (a).

Furthermore, the diameter of each fiber of the porous carbon fiber is 8-15 μm.

(II) NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂The preparation method of the/CFs composite material comprises the following steps:

step 1, stirring porous carbon fibers, a nickel source, a cobalt source and deionized water, and uniformly mixing to obtain a precursor solution; carrying out hydrothermal growth on the precursor solution in a high-pressure kettle to obtain a carbon fiber loaded alkaline nickel cobalt carbonate nanowire primary product; cleaning the primary carbon fiber-loaded basic nickel cobalt carbonate nanowire product to obtain a precursor of the carbon fiber-loaded basic nickel cobalt carbonate nanowire; wherein the atomic ratio of Ni to Co in the carbon fiber-loaded basic nickel cobalt carbonate nanowire precursor is (1.6-2.5) to 1;

step 2, preparing a selenizing solution, respectively adding a precursor of the carbon fiber-loaded basic nickel cobalt carbonate nanowire, an additive and the selenizing solution into deionized water, uniformly mixing, and then carrying out hydrothermal reaction to obtain a carbon fiber-loaded Ni-Co-Se ternary nanostructure primary product; cleaning the carbon fiber loaded Ni-Co-Se ternary nano-structure primary product to obtain a carbon fiber loaded Ni-Co-Se ternary nano-structure;

step 3, putting the carbon fiber-loaded Ni-Co-Se ternary nanostructure in H₂And N₂Carrying out heat treatment under mixed atmosphere to obtain NiSe with micro-nano double-level holes₂-CoSe₂a/CFs composite material.

Further, in the step 1, the temperature of the hydrothermal growth is 110-130 ℃, and the time is 8-10 h.

Further, in step 1, the specific cleaning process is as follows: and cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product by acetone, ethanol and deionized water in sequence, and then carrying out vacuum drying at the temperature of 60-80 ℃ for 10-12 h.

Further, the specific process for preparing the selenizing liquid comprises the following steps: dissolving 0.1-0.6 g of selenium powder in 5-20 mL of hydrazine hydrate, and standing for 36-48 h to obtain the selenium-enriched zinc oxide.

Further, the temperature of the hydrothermal reaction is 180-200 ℃, and the time is 6-10 hours.

Further, in step 2, the specific cleaning process is as follows: and cleaning the carbon fiber-loaded Ni-Co-Se ternary nanostructure primary product by ethanol and deionized water in sequence, placing the cleaned product in a vacuum oven, and then performing vacuum drying at the temperature of 60-80 ℃ for 10-12 h.

Further, in step 3, H₂And N₂The volume ratio of (A) is 1/31-1/21.

Further, in the step 3, the temperature of the heat treatment is 430-480 ℃, the heat preservation time is 50-70 min, and the temperature rise rate is 5-12 ℃/min.

(III) NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂The application of the/CFs composite material in the field of hydrogen production by electrolyzing water.

Compared with the prior art, the invention has the following beneficial effects:

(1) NiSe in the invention₂-CoSe₂the/CFs composite material has micron and nanometerThe existence of the nano pores is beneficial to exposing surface active sites of the electrode active material and fully contacting with electrolyte on one hand, and is beneficial to quickly overflowing small hydrogen bubbles generated by water electrolysis from the nano pore channels to form large bubbles on the other hand, and the existence of the micro pores is beneficial to quickly releasing the formed large bubbles from the electrode structure; to benefit from this, NiSe₂-CoSe₂the/CFs composite exhibits excellent ultraphobicity.

(2) NiSe in the invention₂-CoSe₂The foam-like nano structure in the/CFs composite material is different from the existing nano-wire array or nano-sheet layer array structure, wherein NiSe₂And CoSe₂The cross-linking and the tight combination are realized, and the mechanical stability is excellent while the active sites are fully exposed. When industrial large-current long-time electrolytic water production is carried out, liquid phase and gas phase products on the surface of the electrode are exchanged violently, the long-time impact of high-flux analyzed gas on the electrode has higher requirement on the structural stability of the nano active phase, and the NiSe prepared by the method disclosed by the invention₂-CoSe₂the/CFs composite material can remarkably improve the structural stability of the electrode material in the hydrogen production process by electrolyzing water while ensuring rich active sites and super-gas permeability, and provides important reference for the industrial application of the three-dimensional integrated electrode material for hydrogen production by electrolyzing water.

Drawings

FIG. 1 shows NiSe with micro-nano double-level pores and high structural stability prepared in example 1 of the invention₂-CoSe₂SEM pictures of the/CFs composite material at low magnification;

FIG. 2 shows NiSe with micro-nano double-level pores and high structural stability prepared in embodiment 1 of the invention₂-CoSe₂SEM photograph of/CFs composite material at high magnification;

FIG. 3 is NiSe of the present invention₂-CoSe₂The energy spectrum analysis result of the/CFs composite material shows that the atomic ratio of Ni to Co is 1.79: 1;

FIG. 4 shows NiSe with micro-nano double-level pores and high structural stability prepared in embodiment 1 of the invention₂-CoSe₂The XRD pattern of the/CFs composite material can show that NiSe₂-CoSe₂Middle NiSe₂Mainly cubic phase, with a small amount of orthogonal phase, CoSe₂Is of cubic phase structure.

FIG. 5 shows NiSe prepared according to example 1 of the present invention₂-CoSe₂A voltammetry characteristic curve chart of a water electrolysis hydrogen production performance test of the/CFs composite material;

FIG. 6 shows NiSe prepared according to example 1 of the present invention₂-CoSe₂A current density-time curve diagram of a stability test of water electrolysis hydrogen production of the CFs composite material;

FIG. 7 shows the microfabricated nano-bi-level pore NiSe of the present invention₂-CoSe₂Morphology photo of/CFs composite after 10 hours stability test: 7(a) a low magnification photograph and 7(b) a high magnification photograph;

FIG. 8 shows NiSe of nanowire structure prepared in comparative example 1₂-CoSe₂Comparing morphology photos of the/CFs composite material before and after 10-hour stability test, wherein 8(a) the morphology photo before test, 8(b) the morphology low-power SEM photo after test, and 8(c) the morphology high-power SEM photo after test;

FIG. 9 shows the NiSe of the micro-nano double-level hole of the invention₂-CoSe₂/CFs composite and nanowire Structure NiSe of comparative example₂-CoSe₂And (3) a comparison graph of the change of the active phase loading of the/CFs composite material before and after the stability test of hydrogen production by water electrolysis.

Detailed Description

The present invention is further described below with reference to examples.

Example 1

NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂The preparation method of the/CFs composite material comprises the following steps:

step 1, porous carbon fiber, 0.3g Ni (NO)₃)₂、0.15g CoSO₄Mechanically stirring 0.1g of urea and 30mL of deionized water, and uniformly mixing to obtain a precursor solution; carrying out hydrothermal growth on the precursor solution in a 50mL high-pressure kettle at the hydrothermal growth temperature of 120 ℃ for 8h to obtain a carbon fiber-loaded basic nickel cobalt carbonate nanowire primary product; to the carbon fiber negativeCleaning the primary product of the basic nickel cobalt carbonate nanowire, namely sequentially cleaning the primary product of the basic nickel cobalt carbonate nanowire by acetone, ethanol and deionized water, then placing the primary product in a vacuum oven, and drying the primary product for 12 hours at the temperature of 70 ℃ to obtain a precursor of the carbon fiber-loaded basic nickel cobalt carbonate nanowire; wherein the atomic ratio of Ni to Co in the precursor of the carbon fiber-loaded basic nickel cobalt carbonate nanowire is 2.1: 1;

step 2, preparing a selenizing solution: dissolving 0.2g of selenium powder in 8mL of hydrazine hydrate, and standing for 36h to obtain the selenium powder;

respectively adding the carbon fiber loaded with the basic nickel cobalt carbonate nanowire, 8mL of selenizing solution and 5mL of ethylene glycol into 20mL of deionized water, uniformly mixing, and then carrying out hydrothermal reaction, namely selecting a 50mL high-pressure kettle as a reaction container, wherein the hydrothermal reaction temperature is 180 ℃, and the reaction time is 8 hours, so as to obtain a carbon fiber loaded Ni-Co-Se ternary nanostructure primary product; cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product, namely sequentially cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product with ethanol and deionized water, then placing the cleaned carbon fiber initial product in a vacuum oven, and drying the cleaned carbon fiber loaded Ni-Co-Se ternary nanostructure for 12 hours at the temperature of 70 ℃ to obtain the carbon fiber loaded Ni-Co-Se ternary nanostructure;

step 3, putting the carbon fiber-loaded Ni-Co-Se ternary nanostructure in H₂And N₂Heat treatment is carried out under a mixed atmosphere, wherein H₂And N₂The volume ratio of (1: 31), the heat treatment conditions: keeping the temperature at 450 ℃ for 60 minutes, heating up at the rate of 5 ℃/min, and cooling along with the furnace to obtain the NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂a/CFs composite material.

Example 2

NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂The preparation method of the/CFs composite material comprises the following steps:

step 1, porous carbon fiber, 0.4g Ni (NO)₃)₂、0.2g Co(NO₃)₂Mechanically stirring 0.1g of urea and 35mL of deionized water, and uniformly mixing to obtain a precursor solution; carrying out hydrothermal growth on the precursor solution in a 50mL high-pressure kettle at the hydrothermal growth temperature of 130 ℃ for 10h to obtain the carbon fiber loaded basic nickel cobalt carbonatePrimary products of the nano wires; cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product, namely sequentially cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product by acetone, ethanol and deionized water, then placing the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product in a vacuum oven, and drying the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product for 12 hours at the temperature of 70 ℃ to obtain a carbon fiber loaded basic nickel cobalt carbonate nanowire precursor;

wherein the atomic ratio of Ni to Co in the precursor of the carbon fiber-loaded basic nickel cobalt carbonate nanowire is 2: 1;

step 2, preparing a selenizing solution: dissolving 0.6g of selenium powder in 15mL of hydrazine hydrate, and standing for 48 hours to obtain the selenium powder;

respectively adding carbon fiber loaded with basic nickel cobalt carbonate nanowires, 5mL of selenizing solution and 2mL of glycerol into 30mL of deionized water, uniformly mixing, and then carrying out hydrothermal reaction, namely selecting a 50mL high-pressure kettle as a reaction container, wherein the hydrothermal reaction temperature is 200 ℃, and the reaction time is 6 hours, so as to obtain a carbon fiber loaded Ni-Co-Se ternary nanostructure primary product; cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product, namely sequentially cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product with ethanol and deionized water, then placing the cleaned carbon fiber initial product in a vacuum oven, and drying the cleaned carbon fiber loaded Ni-Co-Se ternary nanostructure for 12 hours at the temperature of 70 ℃ to obtain the carbon fiber loaded Ni-Co-Se ternary nanostructure;

step 3, putting the carbon fiber-loaded Ni-Co-Se ternary nanostructure in H₂And N₂Heat treatment is carried out under a mixed atmosphere, wherein H₂And N₂The volume ratio of (A) to (B) is 1: 25, and the heat treatment conditions are as follows: keeping the temperature at 460 ℃ for 50 minutes, heating up at a rate of 10 ℃/min, and cooling with the furnace to obtain NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂a/CFs composite material.

Example 3

NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂The preparation method of the/CFs composite material comprises the following steps:

step 1, porous carbon fiber and 0.28g of NiSO are mixed₄、0.15gCo(NO₃)₂Mechanically stirring 0.1g of urea and 30mL of deionized water, and uniformly mixing to obtain a precursor solution; carrying out hydrothermal growth on the precursor solution in a 50mL high-pressure kettle at the hydrothermal growth temperature of 120 DEG CThe reaction time is 10 hours, and a primary product of the carbon fiber loaded basic nickel cobalt carbonate nanowire is obtained; cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product, namely sequentially cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product by acetone, ethanol and deionized water, then placing the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product in a vacuum oven, and drying the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product for 12 hours at the temperature of 70 ℃ to obtain a carbon fiber loaded basic nickel cobalt carbonate nanowire precursor;

wherein the atomic ratio of Ni to Co in the precursor of the carbon fiber-loaded basic nickel cobalt carbonate nanowire is 1.8: 1;

step 2, preparing a selenizing solution: dissolving 0.6g of selenium powder in 20mL of hydrazine hydrate, and standing for 48 hours to obtain the selenium powder;

respectively adding the carbon fiber loaded with the basic nickel cobalt carbonate nanowire, 10mL of selenizing solution and 2mL of ethylene glycol into 25mL of deionized water, uniformly mixing, and then carrying out hydrothermal reaction, namely selecting a 50mL high-pressure kettle as a reaction container, wherein the hydrothermal reaction temperature is 200 ℃, and the reaction time is 10 hours, so as to obtain a carbon fiber loaded Ni-Co-Se ternary nanostructure primary product; cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product, namely sequentially cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product with ethanol and deionized water, then placing the cleaned carbon fiber initial product in a vacuum oven, and drying the cleaned carbon fiber loaded Ni-Co-Se ternary nanostructure for 12 hours at the temperature of 70 ℃ to obtain the carbon fiber loaded Ni-Co-Se ternary nanostructure;

step 3, putting the carbon fiber-loaded Ni-Co-Se ternary nanostructure in H₂And N₂Heat treatment is carried out under a mixed atmosphere, wherein H₂And N₂The volume ratio of (1: 21), the heat treatment conditions: the NiSe is processed by heat preservation for 50 minutes at 480 ℃ with the heating rate of 12 ℃/min and is cooled along with the furnace, thus obtaining the NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂a/CFs composite material.

Example 4

NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂The preparation method of the/CFs composite material comprises the following steps:

step 1, porous carbon fiber and 0.18g of NiSO are mixed₄、0.1g CoSO₄Mechanically stirring 0.1g of urea and 35mL of deionized water, and uniformly mixing to obtain a precursor solution; the precursor solution was placed in a 50mL autoclaveCarrying out hydrothermal growth at the temperature of 110 ℃ for 10h to obtain a primary carbon fiber-loaded basic nickel cobalt carbonate nanowire product; cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product, namely sequentially cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product by acetone, ethanol and deionized water, then placing the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product in a vacuum oven, and drying the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product for 12 hours at the temperature of 70 ℃ to obtain a carbon fiber loaded basic nickel cobalt carbonate nanowire precursor;

wherein the atomic ratio of Ni to Co in the precursor of the carbon fiber-loaded basic nickel cobalt carbonate nanowire is 1.7: 1;

step 2, preparing a selenizing solution: dissolving 0.4g of selenium powder in 15mL of hydrazine hydrate, and standing for 40h to obtain the selenium powder;

respectively adding carbon fiber loaded with basic nickel cobalt carbonate nanowires, 8mL of selenizing solution and 3mL of ethylene glycol into 27mL of deionized water, uniformly mixing, and then carrying out hydrothermal reaction, namely selecting a 50mL high-pressure kettle as a reaction container, wherein the hydrothermal reaction temperature is 190 ℃ and the reaction time is 8h, so as to obtain a carbon fiber loaded Ni-Co-Se ternary nanostructure primary product; cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product, namely sequentially cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product with ethanol and deionized water, then placing the cleaned carbon fiber initial product in a vacuum oven, and drying the cleaned carbon fiber loaded Ni-Co-Se ternary nanostructure for 12 hours at the temperature of 70 ℃ to obtain the carbon fiber loaded Ni-Co-Se ternary nanostructure;

step 3, putting the carbon fiber-loaded Ni-Co-Se ternary nanostructure in H₂And N₂Heat treatment is carried out under a mixed atmosphere, wherein H₂And N₂The volume ratio of (1: 26), the heat treatment conditions: keeping the temperature at 470 ℃ for 70 minutes, heating up at the rate of 8 ℃/min, and cooling along with the furnace to obtain the NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂a/CFs composite material.

Example 5

NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂The preparation method of the/CFs composite material comprises the following steps:

step 1, porous carbon fiber, 0.3g Ni (NO)₃)₂、0.12g Co(NO₃)₂0.1g of urea and 25mL of deionized water were mechanically stirredUniformly mixing to obtain a precursor solution; carrying out hydrothermal growth on the precursor solution in a 50mL high-pressure kettle at the hydrothermal growth temperature of 120 ℃ for 8h to obtain a carbon fiber-loaded basic nickel cobalt carbonate nanowire primary product; cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product, namely sequentially cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product by acetone, ethanol and deionized water, then placing the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product in a vacuum oven, and drying the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product for 12 hours at the temperature of 70 ℃ to obtain a carbon fiber loaded basic nickel cobalt carbonate nanowire precursor;

wherein the atomic ratio of Ni to Co in the precursor of the carbon fiber-loaded basic nickel cobalt carbonate nanowire is 2.5: 1;

step 2, preparing a selenizing solution: dissolving 0.2g of selenium powder in 20mL of hydrazine hydrate, and standing for 45 h to obtain the selenium powder;

respectively adding the carbon fiber loaded with the basic nickel cobalt carbonate nanowire, 12mL of selenizing solution and 2mL of ethylene glycol into 20mL of deionized water, uniformly mixing, and then carrying out hydrothermal reaction, namely selecting a 50mL high-pressure kettle as a reaction container, wherein the hydrothermal reaction temperature is 180 ℃, and the reaction time is 6 hours, so as to obtain a carbon fiber loaded Ni-Co-Se ternary nanostructure primary product; cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product, namely sequentially cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product with ethanol and deionized water, then placing the cleaned carbon fiber initial product in a vacuum oven, and drying the cleaned carbon fiber loaded Ni-Co-Se ternary nanostructure for 12 hours at the temperature of 70 ℃ to obtain the carbon fiber loaded Ni-Co-Se ternary nanostructure;

step 3, putting the carbon fiber-loaded Ni-Co-Se ternary nanostructure in H₂And N₂Heat treatment is carried out under a mixed atmosphere, wherein H₂And N₂The volume ratio of (A) to (B) is 1: 24, and the heat treatment conditions are as follows: keeping the temperature at 430 ℃ for 50 minutes, heating up at the rate of 5 ℃/min, and cooling along with the furnace to obtain the NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂a/CFs composite material.

Example 6

NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂The preparation method of the/CFs composite material comprises the following steps:

step 1, porous carbon fiber and 0.25g of NiSO are mixed₄、0.12gCo(NO₃)₂Mechanically stirring 0.1g of urea and 35mL of deionized water, and uniformly mixing to obtain a precursor solution; carrying out hydrothermal growth on the precursor solution in a 50mL high-pressure kettle at the hydrothermal growth temperature of 110 ℃ for 10h to obtain a carbon fiber-loaded basic nickel cobalt carbonate nanowire primary product; cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product, namely sequentially cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product by acetone, ethanol and deionized water, then placing the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product in a vacuum oven, and drying the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product for 12 hours at the temperature of 70 ℃ to obtain a carbon fiber loaded basic nickel cobalt carbonate nanowire precursor;

wherein the atomic ratio of Ni to Co in the precursor of the carbon fiber-loaded basic nickel cobalt carbonate nanowire is 2.3: 1;

step 2, preparing a selenizing solution: dissolving 0.5g of selenium powder in 20mL of hydrazine hydrate, and standing for 48 hours to obtain the selenium powder;

respectively adding carbon fiber loaded with basic nickel cobalt carbonate nanowire, 5mL of selenizing solution and 1mL of glycerol into 30mL of deionized water, uniformly mixing, and then carrying out hydrothermal reaction, namely selecting a 50mL high-pressure kettle as a reaction container, wherein the hydrothermal reaction temperature is 200 ℃, and the reaction time is 7h, so as to obtain a carbon fiber loaded Ni-Co-Se ternary nanostructure primary product; cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product, namely sequentially cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product with ethanol and deionized water, then placing the cleaned carbon fiber initial product in a vacuum oven, and drying the cleaned carbon fiber loaded Ni-Co-Se ternary nanostructure for 12 hours at the temperature of 70 ℃ to obtain the carbon fiber loaded Ni-Co-Se ternary nanostructure;

step 3, putting the carbon fiber-loaded Ni-Co-Se ternary nanostructure in H₂And N₂Heat treatment is carried out under a mixed atmosphere, wherein H₂And N₂The volume ratio of (1: 31), the heat treatment conditions: keeping the temperature at 480 ℃ for 70 minutes, heating up at the rate of 12 ℃/min, and cooling along with the furnace to obtain the NiSe with micro-nano double-stage holes and high structural stability₂-CoSe₂a/CFs composite material.

In the above embodiments, the porous carbon fiber is a commercial carbon fiber purchased and needs to be washed with ethanol before use, and the diameter of each carbon fiber is about 10 μm. The autoclave was a Teflon kettle liner fitted with a stainless steel kettle jacket and had a volume of 50 mL.

Comparative example 1

NiSe with nanowire structure₂-CoSe₂The preparation method of the/CFs composite material comprises the following steps:

step 1, porous carbon fiber, 0.1g Ni (NO)₃)₂、0.4g Co(NO₃)₂Mechanically stirring 0.05g of urea and 30mL of deionized water, and uniformly mixing to obtain a precursor solution; carrying out hydrothermal growth on the precursor solution in a 50mL high-pressure kettle at the hydrothermal growth temperature of 140 ℃ for 6h to obtain a carbon fiber-loaded basic nickel cobalt carbonate nanowire primary product; cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product, namely sequentially cleaning the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product by acetone, ethanol and deionized water, then placing the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product in a vacuum oven, and drying the carbon fiber loaded basic nickel cobalt carbonate nanowire primary product for 12 hours at the temperature of 70 ℃ to obtain a carbon fiber loaded basic nickel cobalt carbonate nanowire precursor;

wherein the atomic ratio of Ni to Co in the carbon fiber loaded basic nickel cobalt carbonate nanowire precursor is 1: 4;

step 2, preparing a selenizing solution: dissolving 0.2g of selenium powder in 10mL of hydrazine hydrate, and standing for 48 hours to obtain the selenium powder;

respectively adding carbon fiber loaded with basic nickel cobalt carbonate nanowires and 5mL of selenizing solution into 25mL of deionized water, uniformly mixing, and then carrying out hydrothermal reaction, namely selecting a 50mL high-pressure kettle as a reaction container, wherein the hydrothermal reaction temperature is 220 ℃, and the reaction time is 24h, so as to obtain a carbon fiber loaded Ni-Co-Se ternary nano-structure primary product; cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product, namely sequentially cleaning the carbon fiber loaded Ni-Co-Se ternary nanostructure initial product with ethanol and deionized water, then placing the cleaned carbon fiber initial product in a vacuum oven, and drying the cleaned carbon fiber loaded Ni-Co-Se ternary nanostructure for 12 hours at the temperature of 70 ℃ to obtain the carbon fiber loaded Ni-Co-Se ternary nanostructure;

step 3, putting the carbon fiber-loaded Ni-Co-Se ternary nanostructure in H₂And N₂Heat treatment is carried out under a mixed atmosphere, wherein H₂And N₂The volume ratio of (A) to (B) is 1: 25, and the heat treatment conditions are as follows: keeping the temperature at 380 ℃ for 30 minutes, heating up at the rate of 12 ℃/min, and cooling along with the furnace to obtain NiSe with a nanowire structure₂-CoSe₂a/CFs composite material.

NiSe prepared in example 1 and having micro-nano double-stage pores and high structural stability₂-CoSe₂The morphology, energy spectrum and XRD test of the/CFs composite material are shown in figures 1-4, and NiSe prepared by the invention can be seen from figures 1 and 2₂-CoSe₂The nano particles are in a net foam structure, are mutually crosslinked and tightly combined, have a pore size of about 200 nm-1 mu m, provide abundant overflow channels for the electrolyzed water gas product while exposing a large number of active reaction sites, and the EDS result in figure 3 shows that the atomic ratio of Ni to Co in the product is 1.8: 1. from the XRD pattern result of FIG. 4, NiSe is known₂-CoSe₂The phase of the material is cubic NiSe₂And CoSe₂And quadrature phase NiSe₂Mainly comprises the following steps.

The product prepared by the embodiment of the invention is subjected to water electrolysis hydrogen production performance and stability test by adopting an electrochemical workstation (Autolab PGSTAT 128N) three-electrode system. Test experiments: the counter electrode is a graphite rod, the reference electrode is Ag/AgCl, high-purity nitrogen is continuously introduced into the electrolyte before testing to discharge dissolved oxygen, and the reference electrode is close to the working electrode as much as possible in the testing process to reduce series resistance. And the electrolyte is continuously stirred in the test process so as to accelerate the mass transfer process of the electrolyte and the desorption of hydrogen. The test potential interval is selected to be between 0.1 and-0.4V (vs. RHE), and the scanning speed is set to be 5mV^-1So as to reduce the interference of polarization phenomenon to the hydrogen evolution current. Before testing, the cathode material is activated, and the scanning speed is set to be 100 mV.s in the same potential interval^-1After the working electrode is stabilized, the linear voltammetry characteristic curve can be tested and recorded, and the result is shown in fig. 5. As can be seen from FIG. 5, at drive 300mA em^-2The hydrogen production current density needs 273mV over potential, and the hydrogen production current density has excellent hydrogen production activity by electrolysis. The stability of hydrogen production by electrolyzed water is tested by an i-t mode, and the i-t curve of figure 6 shows that the composite material prepared by the invention is 100 mA-em^-2Almost no decay is generated after 10 hours of continuous hydrogen production under the current density of (1).

FIGS. 7(a) and (b) are NiSe with micro-nano double-level holes in the invention₂-CoSe₂/CFsThe morphology picture of the composite material after the stability test shows that the active phase micro-nano structure is almost unchanged; furthermore, NiSe nanowire prepared in comparative example₂-CoSe₂The results of the micro-topography test before and after the stability test of the CFs are shown in FIGS. 8(a) - (c), FIG. 8(a) is the topography photo before the stability test, FIGS. 8(b) and (c) are the topography photo after the stability test, and the NiSe nanowire can be seen₂-CoSe₂The active phase structure of the/CFs is very seriously detached after the stability test. FIG. 9 shows NiSe with micro-nano double-level holes in the invention₂-CoSe₂/CFs composite and nanowire NiSe prepared in comparative example 1₂-CoSe₂The active phase loading amount of the/CFs composite material before the stability test and the loss amount of the composite material after the stability test can be quantitatively seen, and NiSe with micro-nano double-level holes₂-CoSe₂the/CFs composite material shows good structural stability in the process of producing hydrogen by electrolyzing water.

The invention utilizes a hydrothermal method and a chemical vapor deposition method to prepare NiSe with a carbon fiber-supported hyperstable foam structure₂-CoSe₂Composite material of formula (I) in₂+N₂To NiSe under atmosphere₂-CoSe₂The crystallinity of the composite structure powder is further improved by heat treatment; the invention can realize the micro regulation and control of the composite structure by adjusting the raw material proportion, the hydrothermal reaction parameters and the chemical gas phase reaction process parameters.

NiSe with micro-nano double-stage holes prepared by the invention₂-CoSe₂the/CFs composite material is used in the field of new energy sources for hydrogen production by industrial electrolytic water, and can improve the structural stability of the hydrogen production electrode under the condition of large current long-time service. The invention prepares NiSe loaded on the surface of a porous carbon fiber substrate and having an ultra-stable foam structure by combining a hydrothermal method with a chemical vapor deposition method₂-CoSe₂Composite material with cubic phase and orthorhombic phase NiSe₂、CoSe₂The microstructure is a typical reticulated foam structure, the pores of the reticulated foam structure are in a submicron level, and the reticulated foam structure can provide a large amount of overflow channels for gas generated by water splitting, so that the bubble overpotential is reduced; at the same timeNiSe₂And CoSe₂The two nanostructures interweave with each other to form a stable foam structure, which also allows NiSe₂-CoSe₂The nano composite structure has excellent mechanical stability. Compared with the reported M (Co, Ni) -Se of the current published data₂The invention relates to a three-dimensional integrated electrode structure which can relieve the destructive effect of gas impact on the stability of an active phase structure under the condition of long-time service of industrial large current and remarkably improve the mechanical stability of an electrode, thereby prolonging the service life of the electrode and reducing the cost of electrolyzed water.

Although the present invention has been described in detail in this specification with reference to specific embodiments and illustrative embodiments, it will be apparent to those skilled in the art that modifications and improvements can be made thereto based on the present invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.