CN117684208A - A sulfur-doped NiSe2 nanosheet/carbon cloth electrode material and its preparation method - Google Patents

Abstract

The invention discloses a sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material and a preparation method thereof. The preparation method includes: first, placing the carbon pretreated by hydrochloric acid hydrophilization on nickel nitrate hexahydrate, chloride Hydrothermal reaction in a mixed aqueous solution of ammonium and urea produces Ni(OH) ₂ nanosheet/carbon cloth precursor; then, sulfur powder, selenium powder and Ni(OH) ₂ nanosheet/carbon cloth precursor are put into tubes respectively In a conventional furnace, the chemical vapor deposition method was used to prepare sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode materials. The present invention adopts the simultaneous sublimation of sulfur powder and selenium powder, and introduces sulfur doping while elemental selenium reacts with Ni(OH) ₂ nanosheets to generate NiSe ₂ nanosheets, thereby obtaining a sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material. By regulating the doping of sulfur, the electronic structure of _NiSe2 is optimized and the density of catalytically active sites is increased, thereby improving the electrochemical catalytic activity of the material.

Description

A sulfur-doped NiSe2 nanosheet/carbon cloth electrode material and its preparation method

Technical field

The invention belongs to the technical field of electrocatalytic material preparation, and specifically relates to a sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material and a preparation method thereof.

Background technique

With the acceleration of the global economy and urbanization, traditional fossil energy has been consumed in large quantities, and problems such as energy depletion and environmental degradation have become increasingly serious. The use of clean energy, such as hydrogen, to replace fossil fuels is an inevitable trend in human development in the future. Hydrogen production by electrolysis of water is one of the effective strategies for large-scale hydrogen production. The anodic oxidation reaction of electrolyzed water is the oxygen evolution reaction (OER). Because the oxygen evolution process involves four electron reactions, the slow chemical reaction kinetics results in a higher overpotential. Therefore, reducing the overpotential in the OER reaction is the key to control. The key to the cost of hydrogen production through electrolysis of water. To date, noble metals are considered the most active catalysts for water electrolysis. However, their scarcity and high cost limit their widespread and long-term applications. Therefore, the development of high-performance and inexpensive non-noble metal electrocatalysts, such as transition metal selenides, deserves great attention.

Publication number CN116180105A "A ruthenium-doped nickel selenide film catalyst and its preparation method" uses selenium powder, sodium borohydride and deionized water to mix to obtain solution A, and an appropriate amount of Ni(NO ₃ ) ₃ and ethanol are mixed to obtain a solution B, mix solutions A and B to obtain solution C; then put solution C and pretreated nickel foam into a hydrothermal kettle, and perform hydrothermal treatment at a reaction temperature of 120~180°C and a time of 5.0~12.0 h. After the reaction, clean and dry to obtain a NiSe ₂ film; soak the obtained NiSe ₂ film in a RuCl ₃ aqueous solution for 6 to 24 hours, then take out the sample and dry it at room temperature, and finally put the sample into a tube furnace for high temperature treatment under the protection of inert gas. Calcination, the calcination treatment temperature is 250~500℃, and the time is 1.0~3.0 h. The resulting material is a Ru-NiSe ₂ film. The precious metal ruthenium is used in this method, and its high cost and low reserves greatly limit the large-scale preparation of this method.

In the publication number CN115584534A "A sulfur-doped nickel-iron-based composite electrocatalyst and preparation method and application", the metallic nickel substrate after plasma cleaning treatment at 100~500 W power for 10 min~1 h is immersed in In a mixed solution of soluble iron salt and thiosulfate with a concentration ratio of 0.1~1M, soak it after ultrasonic treatment, take it out and dry it, to obtain a sulfur-doped nickel-iron-based composite electrocatalyst. In this method, thiosulfate is used as the sulfur source dopant, which can easily introduce other impurity ions while introducing sulfide ions, thus affecting its electrochemical performance.

In the publication number CN113201753A "Preparation method of phosphorus-doped nickel selenide and its application in electrolysis water catalyst", the cleaned strip-shaped nickel foam, selenium powder and phosphorus source are respectively placed into a fused quartz tube, wherein the nickel foam: The mass ratio of selenium powder: phosphorus source is 2~10 g: 100~300 mg: 5~15 mg; the three reaction raw materials placed separately are heated to 300~500 ℃ at a heating rate of 10~30 ℃∙min ^-1 in an inert state. Keep it under gas protection for 20-60 minutes, cool to room temperature, and after cleaning, phosphorus-doped nickel selenide is obtained. In this method, nickel foam is directly used as the nickel source, and the product is obtained by reacting with selenium powder and phosphorus source. It cannot effectively control the exposed crystal face of the nickel selenide material, and due to the high reaction temperature, it is easy to cause the nickel foam skeleton to break, affecting Efficiency of self-supporting nickel selenide catalysts on electrodes.

Contents of the invention

The purpose of the present invention is to provide an efficient method for preparing sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode materials. The present invention uses the chemical vapor deposition method to utilize the simultaneous sublimation of sulfur powder and selenium powder, introduce gaseous sulfur elemental substance and gaseous elemental selenium into the tube furnace, and react with Ni(OH) ₂ nanosheets grown on the surface of the carbon cloth to prepare sulfur Doped NiSe ₂ nanosheet/carbon cloth electrode material. Sulfur doping can cause NiSe ₂ lattice distortion, effectively optimize the NiSe ₂ electronic structure, increase the density of electrocatalytic active sites, and ensure the excellent electronic performance of the three-dimensional NiSe ₂ /carbon cloth structure without adding additional surfactants or binders. Transmission capabilities and interconnection characteristics. Compared with traditional nickel selenide materials, the catalytic performance and stability of the prepared sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material are significantly improved. The preparation method has the characteristics of high efficiency, low cost, safe and simple operation, etc.

In order to achieve the above objects, the present invention adopts the following technical solutions:

A method for preparing sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode materials, using hydrothermal method and chemical vapor deposition method respectively, without adding additional surfactants or binders, to grow sulfur-doped on the carbon cloth substrate NiSe ₂ nanosheets; specifically includes the following steps:

(1) Pretreatment of carbon cloth: After ultrasonic hydrophilization treatment of carbon cloth with 3 mol/L hydrochloric acid for 1 hour, it was immersed in acetone, ethanol and deionized water in sequence, and continued ultrasonic treatment for 15 minutes to remove its surface oxide layer, and then 60 ℃ vacuum drying carbon cloth for later use;

(2) Preparation of Ni(OH) ₂ nanosheet/carbon cloth precursor: Mix nickel nitrate hexahydrate, ammonium chloride, urea and deionized water, ultrasonicate for 30 minutes to obtain a light green solution, and then perform step (1) ), the carbon cloth and solution after pretreatment were transferred to a polytetrafluoroethylene hydrothermal kettle, left to stand overnight, reacted at 120°C for 6 h, washed with deionized water and dried to obtain Ni(OH) ₂ nanosheets /Carbon cloth precursor;

(3) Preparation of sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material: Take sulfur powder, selenium powder and the Ni(OH) ₂ nanosheet/carbon cloth precursor prepared in step (2) and place them in a tube furnace , put the sulfur powder and selenium powder in the upwind, react at 450°C for 1 hour in a nitrogen atmosphere, and obtain the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material.

Preferably, the size of the carbon cloth described in step (1) is 2×2 cm.

Preferably, the added amount of nickel nitrate hexahydrate described in step (2) is 145 mg, the added amount of ammonium chloride is 107 mg, the added amount of urea is 150 mg, and the added amount of deionized water is 20 mL.

Preferably, the amount of sulfur powder in step (3) is 1 to 7 mg, and the amount of selenium powder is 75 mg, both in powder form. The size of the Ni(OH) ₂ nanosheet/carbon cloth precursor is 1 × 2 cm, and the heating rate of the tube furnace is 20 ℃/min.

The sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material prepared by the above method can be used to catalyze the electrolysis of water reaction.

Compared with existing technology, the beneficial effects of the present invention are:

(1) Through sulfur doping, NiSe ₂ lattice distortion is caused, the electronic structure is optimized, the catalytic active site density is increased, and the OER performance is improved: The present invention uses the chemical vapor deposition method to utilize the simultaneous sublimation of sulfur powder and selenium powder. , introducing gaseous sulfur elemental substance and gaseous elemental selenium into a tube furnace, reacting with Ni(OH) ₂ nanosheets grown on the surface of carbon cloth, to prepare sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material. The reaction equation is as follows:

(2) The preparation process is simple and low-cost: hydrothermal method and chemical vapor deposition method are used to grow sulfur-doped NiSe ₂ nanosheets on the carbon cloth substrate, and can be directly used as electrode materials for electrolysis of water without adding additional surfaces. The active agent or binder ensures the charge transfer efficiency necessary for electrode operation and reduces the preparation cost.

(3) High efficiency and resource saving: The synthetic product process of the present invention requires few raw materials and no other dangerous chemical raw materials. During the entire product preparation process, only a small amount of low-toxic industrial waste is produced for post-processing, which embodies the low-carbon economy. and the concept of sustainable development.

Description of the drawings

Figure 1 is the X-ray diffraction data diagram of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material and the undoped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1 and Comparative Example 1 of the present invention;

Figure 2 is a scanning electron microscope data diagram of the undoped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Comparative Example 1 of the present invention;

Figure 3 is a scanning electron microscope data diagram of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1 of the present invention;

Figure 4 is a high-resolution transmission electron microscope data diagram of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1 of the present invention;

Figure 5 is an element distribution diagram of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1 of the present invention;

Figure 6 is the precipitation of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material and the undoped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1 and Comparative Example 1 of the present invention in a 1 mol/L KOH solution. Oxygen polarization curve;

Figure 7 is a chronovoltage curve of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1 of the present invention in a 1 mol/L KOH solution at a current density of 10 mA·cm ^-2 .

Detailed ways

In order to make the content of the present invention easier to understand, the technical solutions described in the present invention will be further described below in conjunction with specific embodiments. However, the embodiments are intended to explain the present invention and should not be understood as limiting the present invention.

Example 1

(1) Pretreatment of carbon cloth: After ultrasonic hydrophilization of a 2×2 cm piece of carbon cloth with 3 mol/L hydrochloric acid for 1 hour, immerse it in acetone, ethanol and deionized water in sequence, and continue ultrasonic treatment for 15 minutes to remove it. Surface oxide layer, and then vacuum dry the carbon cloth at 60°C for later use;

(2) Mix 145 mg nickel nitrate hexahydrate, 107 mg ammonium chloride, 150 mg urea and 20 mL deionized water. After ultrasonic treatment for 30 minutes, obtain a light green solution, and then use the carbon cloth pretreated in step (1). Transfer the solution to a polytetrafluoroethylene hydrothermal kettle, let it stand overnight, react at 120°C for 6 hours, wash with deionized water and dry to obtain the Ni(OH) ₂ nanosheet/carbon cloth precursor;

(3) Weigh 5 mg of sulfur powder and 75 mg of selenium powder respectively and place them at one end of the porcelain boat, then cut the Ni(OH) ₂ nanosheet/carbon cloth precursor prepared in step (2) into 1×2 cm and place it on The other end of the porcelain boat. The porcelain boat was then placed in a tube furnace so that the sulfur powder and selenium powder were in the upwind, and the reaction was carried out at 450°C for 1 h in a nitrogen atmosphere to obtain a sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material.

Example 2

(1) Pretreatment of carbon cloth: After ultrasonic hydrophilization of a 2×2 cm piece of carbon cloth with 3 mol/L hydrochloric acid for 1 hour, immerse it in acetone, ethanol and deionized water in sequence, and continue ultrasonic treatment for 15 minutes to remove it. Surface oxide layer, and then vacuum dry the carbon cloth at 60°C for later use;

(2) Mix 145 mg nickel nitrate hexahydrate, 107 mg ammonium chloride, 150 mg urea and 20 mL deionized water. After ultrasonic treatment for 30 minutes, obtain a light green solution, and then use the carbon cloth pretreated in step (1). Transfer the solution to a polytetrafluoroethylene hydrothermal kettle, let it stand overnight, react at 120°C for 6 hours, wash with deionized water and dry to obtain the Ni(OH) ₂ nanosheet/carbon cloth precursor;

(3) Weigh 3 mg of sulfur powder and 75 mg of selenium powder respectively and place them at one end of the porcelain boat, then cut the Ni(OH) ₂ nanosheet/carbon cloth precursor prepared in step (2) into 1×2 cm and place it on The other end of the porcelain boat. The porcelain boat was then placed in a tube furnace so that the sulfur powder and selenium powder were in the upwind, and the reaction was carried out at 450°C for 1 h in a nitrogen atmosphere to obtain a sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material.

Example 3

(1) Pretreatment of carbon cloth: After ultrasonic hydrophilization of a 2×2 cm piece of carbon cloth with 3 mol/L hydrochloric acid for 1 hour, immerse it in acetone, ethanol and deionized water in sequence, and continue ultrasonic treatment for 15 minutes to remove it. Surface oxide layer, and then vacuum dry the carbon cloth at 60°C for later use;

(2) Mix 145 mg nickel nitrate hexahydrate, 107 mg ammonium chloride, 150 mg urea and 20 mL deionized water. After ultrasonic treatment for 30 minutes, obtain a light green solution, and then use the carbon cloth pretreated in step (1). Transfer the solution to a polytetrafluoroethylene hydrothermal kettle, let it stand overnight, react at 120°C for 6 hours, wash with deionized water and dry to obtain the Ni(OH) ₂ nanosheet/carbon cloth precursor;

(3) Weigh 7 mg of sulfur powder and 75 mg of selenium powder respectively and place them at one end of the porcelain boat, then cut the Ni(OH) ₂ nanosheet/carbon cloth precursor prepared in step (2) into 1×2 cm and place it on The other end of the porcelain boat. The porcelain boat was then placed in a tube furnace so that the sulfur powder and selenium powder were in the upwind, and the reaction was carried out at 450°C for 1 h in a nitrogen atmosphere to obtain a sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material.

Comparative Example 1 (without sulfur doping)

(1) Pretreatment of carbon cloth: After ultrasonic hydrophilization of a 2×2 cm piece of carbon cloth with 3 mol/L hydrochloric acid for 1 hour, immerse it in acetone, ethanol and deionized water in sequence, and continue ultrasonic treatment for 15 minutes to remove it. Surface oxide layer, and then vacuum dry the carbon cloth at 60°C for later use;

(2) Mix 145 mg nickel nitrate hexahydrate, 107 mg ammonium chloride, 150 mg urea and 20 mL deionized water. After ultrasonic treatment for 30 minutes, obtain a light green solution, and then use the carbon cloth pretreated in step (1). Transfer the solution to a polytetrafluoroethylene hydrothermal kettle, let it stand overnight, react at 120°C for 6 hours, wash with deionized water and dry to obtain the Ni(OH) ₂ nanosheet/carbon cloth precursor;

(3) Weigh 75 mg of selenium powder and place it at one end of the porcelain boat, then cut the Ni(OH) ₂ nanosheet/carbon cloth precursor prepared in step (2) to 1×2 cm and place it at the other end of the porcelain boat. The porcelain boat was then placed in a tube furnace, with the selenium powder in the upwind, and reacted at 450°C for 1 hour in a nitrogen atmosphere to obtain NiSe ₂ nanosheet/carbon cloth electrode material.

Figure 1 is the X-ray diffraction pattern of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material in Example 1 and the undoped NiSe ₂ nanosheet/carbon cloth electrode material in Comparative Example 1. It can be seen from the figure , the diffraction peak of the prepared undoped NiSe ₂ nanosheet/carbon cloth electrode material corresponds to NiSe ₂ (PDF#88-1711); and the prepared sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material also has the same The diffraction peak corresponds to NiSe ₂ , indicating that sulfur exists in the NiSe ₂ phase in the form of doping. As shown in the inset of the figure, it can be seen that compared with the undoped NiSe ₂ nanosheet/carbon cloth electrode material, the diffraction peak corresponding to the (210) crystal plane of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material is toward A high angle produces a certain angle shift, indicating that sulfur doping causes NiSe ₂ lattice distortion, resulting in a smaller NiSe ₂ interplanar spacing.

Figures 2 and 3 are respectively scanning electron microscopy images of the undoped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Comparative Example 1 and the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Implementation 1. From the figure It can be seen that the undoped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Comparative Example 1 exhibits a flake structure. The sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1 also has a flake structure, indicating that sulfur doping does not significantly change the morphology of the NiSe ₂ nanosheet.

Figure 4 is a high-resolution transmission electron microscope image of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1. From the figure, it can be measured that the crystal plane spacing is 0.2658 nm, which is slightly smaller than the corresponding crystal plane of NiSe ₂ For the (210) crystal plane with a spacing of 2.667 nm, the reduction of the crystal plane spacing proves that sulfur is doped into the NiSe ₂ lattice, causing lattice distortion.

Figure 5 is an element distribution diagram of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1. From the figure, it can be clearly seen that Ni, Se and S are evenly distributed in the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material. On carbon cloth electrode material.

A three-electrode system was used to verify the oxygen evolution performance of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1. The electrode to be tested was used as the working electrode, platinum sheet and Ag/AgCl were used as the counter electrode and reference electrode respectively, and 1 mol/L KOH solution (pH=14) was used as the electrolyte. The electrochemical tester uses the CHI 660D electrochemical station (Shanghai Chenhua Instrument Co., Ltd.). The potential test range of the oxygen evolution polarization curve (LSV) is 0~1V ( vs. RHE), and the sweep speed is 5 mV/s. . Figure 6 is the oxygen evolution polarization curve of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material and the undoped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1 and Comparative Example 1. It can be seen from the figure When the current density reaches 10 mA·cm ^-2 , the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material of Example 1 only needs an overpotential of 266 mV, which is better than the undoped NiSe ₂ nanosheet prepared in Comparative Example 1 /334 mV required for the carbon cloth electrode material, showing better electrochemical performance. Figure 7 is a chronopotentiometry test of the durability of the sulfur-doped NiSe ₂ nanosheet/carbon cloth electrode material prepared in Example 1. As can be seen from the figure, under a current density of 10mA·cm ^-2 for 24 consecutive h continuous oxygen evolution test, the potential did not show significant attenuation after the material reached a stable state, reflecting the good stability of the electrode material.

The above embodiments are 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, etc. may be made without departing from the spirit and principles of the present invention. All simplifications should be equivalent substitutions, and are all included in the protection scope of the present invention.

Claims (6)

1. Sulfur doped NiSe ₂ The preparation method of the nano sheet/carbon cloth electrode material is characterized by comprising the following steps: growing sulfur doped NiSe on carbon cloth substrate by hydrothermal method and chemical vapor deposition method ₂ A nanoplatelet array; the method specifically comprises the following steps:

(1) Pretreatment of carbon cloth: ultrasonic treating carbon cloth with 3 mol/L hydrochloric acid for 1 h, sequentially immersing in acetone, ethanol and deionized water, continuing ultrasonic treatment for 15 min to remove the surface oxide layer, and vacuum drying the carbon cloth at 60deg.C for use;

（2）Ni(OH) ₂ preparation of nanoplatelets/carbon cloth precursors: mixing nickel nitrate hexahydrate, ammonium chloride, urea and deionized water, performing ultrasonic treatment for 30 min to obtain a light green solution, transferring the carbon cloth pretreated in the step (1) and the solution into a polytetrafluoroethylene hydrothermal kettle, standing overnight, reacting at 120 ℃ for 6 h, washing with deionized water, and drying to obtain Ni (OH) ₂ Nanosheets/carbon cloth precursors;

(3) Sulfur doped NiSe ₂ Preparing a nano sheet/carbon cloth electrode material: respectively taking sulfur powder, selenium powder and Ni (OH) prepared in the step (2) ₂ The nano sheet/carbon cloth precursor is placed in a tube furnace, sulfur powder and selenium powder are placed in an upper tuyere, and reacted at 450 ℃ in nitrogen atmosphere for 1 h to obtain sulfur doped NiSe ₂ Nanoplatelets/carbonAnd (5) distributing electrode materials.

2. The sulfur-doped NiSe of claim 1 ₂ The preparation method of the nano sheet/carbon cloth electrode material is characterized by comprising the following steps: the carbon cloth in the step (1) has a size of 2×2 cm.

3. The sulfur-doped NiSe of claim 1 ₂ The preparation method of the nano sheet/carbon cloth electrode material is characterized by comprising the following steps: the addition amount of the nickel nitrate hexahydrate in the step (2) is 72.5-290 mg, the addition amount of the ammonium chloride is 107 mg, the addition amount of the urea is 150mg, and the addition amount of the deionized water is 20 mL.

4. The sulfur-doped NiSe of claim 1 ₂ The preparation method of the nano sheet/carbon cloth electrode material is characterized by comprising the following steps: the addition amount of the sulfur powder in the step (3) is 1-7 mg, the addition amount of the selenium powder is 75-mg, and the reaction heating rate is 20 ℃/min.

5. A sulfur-doped NiSe prepared by the method of any one of claims 1 to 4 ₂ Nanosheets/carbon cloth electrode materials.

6. A sulfur-doped NiSe as claimed in claim 5 ₂ The application of the nano-sheet/carbon cloth electrode material in catalyzing the water electrolysis reaction.