Preparation method and application of self-supporting catalyst of nickel diselenide hierarchical nanoneedle array

Abstract

The application discloses a preparation method of a self-supporting catalyst of a nickel diselenide hierarchical nanoneedle array, and belongs to the field of new chemical material catalysis. The method comprises the following steps: dissolving nickel salt, cerium salt, urea and ammonium fluoride in deionized water, stirring and uniformly mixing, placing the mixture and carbon fiber paper in a reaction kettle to perform a hydrothermal reaction, naturally cooling to room temperature after the reaction is completed, taking out the carbon fiber paper, washing and drying, thereby preparing the carbon fiber paper loaded with a nickel precursor array, placing the carbon fiber paper loaded with the nickel precursor array in air to perform calcination, washing and drying the calcination product, adding deionized water and NaHSe solution, uniformly mixing, performing a hydrothermal reaction, naturally cooling to room temperature after the reaction is completed, taking out the carbon fiber paper, washing and drying, thereby obtaining the self-supporting catalyst of the nickel diselenide hierarchical nanoneedle array rich in nickel vacancies. The catalyst prepared by the method is applied to electrocatalytic hydrogen evolution, and the experimental results show that the catalyst has excellent hydrogen evolution performance and has a good application prospect in the field of electrocatalytic hydrogen evolution.

Description

Technical Field

[0001] This invention relates to a method for preparing a self-supporting electrocatalyst with nickel diselenide hierarchical nanoneedle array rich in nickel vacancies, belonging to the field of catalysis in new chemical materials. Background Technology

[0002] Hydrogen energy possesses high gravimetric energy density and is renewable, making it an ideal alternative to fossil fuels. Electrocatalytic hydrogen evolution reaction (HER) is a promising and cost-effective hydrogen production pathway. However, HER kinetics in alkaline solutions are approximately two to three orders of magnitude lower than in acidic solutions, thus improving the performance of alkaline electrocatalytic HER is more challenging.

[0003] In recent years, transition metal selenides have been widely explored as HER electrocatalysts due to their unique electronic structure, tunable chemical composition, and tunable morphology. Among them, nickel diselenide has become one of the most ideal candidates due to its high conductivity and excellent chemical stability over a wide pH range. However, the relatively weak water dissociation and hydrogen adsorption capabilities of bulk NiSe2 inhibit its HER performance under alkaline conditions. Therefore, introducing positively charged Ni cation vacancies may trigger charge redistribution among surrounding Ni and Se atoms, and preparing unique morphologies can increase the number of active sites, thereby improving HER performance under alkaline conditions. Currently, methods for introducing cation vacancies, such as electrochemical etching, plasma etching, acid / base chemical etching, organic molecule-assisted preparation, and non-stoichiometric synthesis, suffer from high energy consumption, harsh conditions, cumbersome procedures, and lack of controllability, which seriously hinder the development of cation vacancy-based electrocatalysts. Therefore, the simple and efficient preparation of selenides with abundant cation vacancies under ambient temperature and pressure is a significant challenge. Summary of the Invention

[0004] To address the problems existing in the prior art, this invention provides a method for preparing a self-supporting electrocatalyst with nickel diselenide hierarchical nanoneedle array rich in nickel vacancies. This method can not only prepare cation vacancy-type electrocatalysts simply and efficiently, but also exhibit excellent electrocatalytic activity through the controllable manipulation of cation vacancies.

[0005] The present invention discloses a method for preparing a self-supporting electrocatalyst rich in nickel vacancies, namely, nickel diselenide hierarchical nanoneedle array, by in-situ growth of a nickel precursor hierarchical nanoneedle array on carbon fiber paper using a hydrothermal reaction vessel, followed by calcination in an air environment in a tube furnace to obtain a nickel oxide hierarchical nanoneedle array, and finally obtaining a NiSe2 hierarchical nanoneedle self-supporting catalyst rich in Ni vacancies through a hydrothermal selenization reaction vessel. This self-supporting electrocatalyst exhibits excellent electrocatalytic hydrogen evolution performance.

[0006] The specific steps of the method of the present invention are as follows:

[0007] (1) Preparation of nickel precursor hierarchical nanoneedle array based on carbon fiber paper

[0008] Nickel salt, cerium salt, urea and ammonium fluoride were dissolved in deionized water and stirred until well mixed. The mixture was then placed in a reactor with carbon fiber paper for hydrothermal reaction. After the reaction was completed, the mixture was naturally cooled to room temperature. The carbon fiber paper was then removed, washed and dried to obtain carbon fiber paper loaded with a nickel precursor array.

[0009] The nickel salt is selected from nickel chloride, nickel nitrate, and nickel acetylacetone, and the cerium salt is selected from cerium nitrate, cerium chloride, and cerium sulfate; the concentration of nickel salt in the mixture is 0.01-1 mol / L, the concentration of cerium salt is 0.01-0.8 mol / L, the concentration of urea is 0.05-0.5 mol / L, and the concentration of ammonium fluoride is 0.02-0.5 mol / L; the hydrothermal reaction temperature is 80-250℃, and the reaction time is 5-48 h;

[0010] The carbon fiber paper used above is model NOS1005;

[0011] (2) Preparation of nickel oxide hierarchical nanoneedle array based on carbon fiber paper

[0012] Carbon fiber paper loaded with nickel precursor array was placed in a tube furnace and calcined in air at 400-900℃ for 2-5 hours at a rate of 1-10℃ / min. After the reaction was completed, the calcined product was washed and dried to obtain carbon fiber paper loaded with nickel oxide hierarchical nanoneedle array.

[0013] (3) Preparation of nickel diselenide hierarchical nanoneedle array rich in nickel vacancies on carbon fiber paper substrate

[0014] Carbon fiber paper loaded with nickel oxide hierarchical nanoneedle arrays was placed in a reaction vessel, then deionized water and NaHSe solution were added to carry out a hydrothermal reaction. After the reaction was completed, the paper was naturally cooled to room temperature. The self-supporting electrode was then removed, washed, and dried to obtain a nickel diselenide hierarchical nanoneedle self-supporting electrocatalyst rich in nickel vacancies.

[0015] The method for preparing the NaHSe solution is as follows:

[0016] Weigh 0.22-3.24 mmol of NaBH4 and place it in a small glass bottle containing 1 mL of argon-saturated deionized water. Then add 0.1-1.5 mmol of Se powder and react at 0 °C for 30 min to obtain a NaHSe solution.

[0017] The hydrothermal reaction temperature is 80-250 ℃, and the reaction time is 5-48 h; the molar ratio of NaHSe to nickel salt is 1:2-10.

[0018] The drying temperature in the above preparation is 30-120℃, and the drying time is 2-48h.

[0019] Another objective of this invention is to apply the nickel diselenide hierarchical nanoneedle array self-supporting catalyst prepared by the above method to electrocatalytic hydrogen evolution.

[0020] The beneficial effects of this invention are as follows:

[0021] Compared with existing methods for preparing cation vacancy-type transition metal-based electrocatalysts and the control of metal vacancies, the method of this invention is mild and simple to operate. The self-supporting catalyst prepared by this invention has a hierarchical nanoneedle array structure that exposes more active sites, promoting mass and charge transport. Nickel vacancies can simultaneously control the electronic structure of metal and non-metal active centers, while the self-supporting macroscopic structure helps to reduce the interfacial contact resistance during electrocatalysis, thus exhibiting excellent electrocatalytic hydrogen evolution activity. Attached Figure Description

[0022] Figure 1 SEM image of the carbon fiber paper prepared in Example 1;

[0023] Figure 2 The XRD pattern of the nickel diselenide hierarchical nanoneedle self-supporting electrocatalyst rich in nickel vacancies supported on carbon fiber paper prepared in Example 1.

[0024] Figure 3 SEM image of the nickel diselenide hierarchical nanoneedle self-supporting electrocatalyst rich in nickel vacancies supported on carbon fiber paper prepared in Example 1.

[0025] Figure 4 The LSV curve of hydrogen evolution electrocatalysis of the nickel diselenide hierarchical nanoneedle self-supporting electrocatalyst rich in nickel vacancies prepared in Example 1.

[0026] Figure 5 Electrocatalytic hydrogen evolution LSV curves of the nickel vacancy-rich nickel diselenide hierarchical nanoneedle self-supporting electrocatalysts prepared in Examples 2, 3 and 4. Detailed Implementation

[0027] The present invention will be further described in detail below through embodiments, but the scope of protection of the present invention is not limited to the contents described therein; unless otherwise specified, the methods in the embodiments are conventional methods, and the reagents are conventional commercial reagents or reagents prepared according to conventional methods unless otherwise specified. Example 1

[0028] Dissolve 1 mmol nickel chloride, 0.5 mmol cerium nitrate, 5.8 mmol urea, and 2.7 mmol ammonium fluoride in 40 mL of deionized water. After stirring and mixing, the mixture is then applied to carbon fiber paper (SEM image shown). Figure 1A carbon fiber paper (with a three-dimensional network structure woven from carbon fibers) was placed in a reactor and hydrothermally reacted at 120°C for 20 hours. After cooling to room temperature, the carbon fiber paper was removed and washed three times each with water and ethanol, and dried at 60°C for 12 hours to obtain carbon fiber paper loaded with a nickel precursor array. The carbon fiber paper loaded with the nickel precursor array was placed in a tube furnace and heated to 500°C at a rate of 5°C / min. It was calcined in air at 500°C for 2 hours. After cooling to room temperature, it was washed three times each with water and ethanol, and dried at 60°C for 12 hours to obtain carbon fiber paper loaded with a nickel oxide hierarchical nanoneedle array. The carbon fiber paper loaded with the nickel oxide hierarchical nanoneedle array, 30 mL of deionized water, and 1 mL of 0.49 mol / L NaHSe solution were mixed and hydrothermally reacted at 120°C for 12 hours. After the reaction was completed and cooled to room temperature, the carbon fiber paper was removed and washed three times each with water and ethanol, and dried at 60°C for 12 hours to obtain a self-supported catalyst V with a nickel vacancy-rich nickel diselenide hierarchical nanoneedle array. Ni The XRD pattern of the NiSe2 / CFP catalyst is shown in [reference needed]. Figure 2 As can be seen from the figure, highly crystalline nickel diselenide with a cubic phase was obtained and grown on carbon fiber paper. The SEM image of the catalyst is shown below. Figure 3 As can be seen from the figure, nickel diselenide nanoneedles on carbon fiber paper grow together to form a nanosheet-like hierarchical structure array.

[0029] Simultaneously, a Pt / C / CFP catalyst was prepared as a control. 10 mg of commercial Pt / C electrocatalyst was weighed and dispersed in a mixed solution of 1 mL ethanol and 0.1 mL 5 wt% Nafion, followed by sonication for 1 h to obtain a catalyst slurry. The slurry was then dropped onto a 1×1 cm⁻¹ plate. 2 The Pt / C / CFP catalyst is obtained on carbon fiber paper.

[0030] The catalyst V prepared in the above examples Ni NiSe2 / CFP and Pt / C / CFP catalysts were applied in the electrocatalytic hydrogen evolution reaction, and the results were as follows: Figure 4 As shown, the nickel diselenide hierarchical nanoneedle self-supporting catalyst V, rich in nickel vacancies. Ni -NiSe2 / CFP exhibits excellent hydrogen evolution performance. Example 2

[0031] 2 mmol nickel nitrate, 1 mmol cerium chloride, 11.6 mmol urea, and 5.4 mmol ammonium fluoride were dissolved in 40 mL deionized water and stirred until homogeneous. The mixture was then placed in a reactor with carbon fiber paper and hydrothermally reacted at 80 °C for 40 h. After cooling to room temperature, the carbon fiber paper was removed and washed three times each with water and ethanol, and dried at 30 °C for 48 h to obtain carbon fiber paper loaded with a nickel precursor array. This carbon fiber paper was then placed in a tube furnace and heated to 800 °C at a rate of 2 °C / min. It was calcined in air at 800 °C for 2 h. After cooling to room temperature, it was washed three times each with water and ethanol, and dried at 30 °C for 48 h to obtain carbon fiber paper loaded with a nickel oxide hierarchical nanoneedle array. The resulting mixture was then combined with 30 mL deionized water and 0.98 mol / L... Mix 1 mL of NaHSe solution and hydrothermally react at 80 °C for 48 h. After the reaction is completed, cool to room temperature, take out the carbon fiber paper, wash it three times with water and three times with ethanol, and dry it at 30 °C for 48 h to obtain a nickel diselenide hierarchical nanoneedle array self-supporting catalyst rich in nickel vacancies.

[0032] The nickel-vacancy-rich nickel diselenide hierarchical nanoneedle array self-supporting catalyst prepared in the above examples was applied to the electrocatalytic hydrogen evolution reaction, and the results are as follows: Figure 5 As shown, nickel diselenide hierarchical nanoneedle self-supporting catalysts rich in nickel vacancies exhibit excellent hydrogen evolution performance. Example 3

[0033] 15 mmol nickel nitrate, 16 mmol cerium sulfate, 10 mmol urea, and 16 mmol ammonium fluoride were dissolved in 40 mL deionized water and stirred until homogeneous. The mixture was then placed in a reactor with carbon fiber paper and hydrothermally reacted at 180 °C for 10 h. After cooling to room temperature, the carbon fiber paper was removed and washed three times each with water and ethanol, and dried at 90 °C for 12 h to obtain carbon fiber paper loaded with a nickel precursor array. The carbon fiber paper loaded with the nickel precursor array was placed in a tube furnace and heated to 600 °C at a rate of 10 °C / min. It was calcined in air at 600 °C for 4 h. After cooling to room temperature, it was washed three times each with water and ethanol, and dried at 90 °C for 12 h to obtain carbon fiber paper loaded with a nickel oxide hierarchical nanoneedle array. The carbon fiber paper loaded with the nickel oxide hierarchical nanoneedle array was then reacted with 30 mL of deionized water and 1.47 mol / L... Mix 1 mL of NaHSe solution and hydrothermally react at 180 °C for 15 h. After the reaction is complete, cool to room temperature, remove carbon fiber paper, wash with water and ethanol three times each, and dry at 90 °C for 12 h to obtain nickel diselenide hierarchical nanoneedle array self-supporting catalyst rich in nickel vacancies.

[0034] The nickel-vacancy-rich nickel diselenide hierarchical nanoneedle array self-supporting catalyst prepared in the above examples was applied to the electrocatalytic hydrogen evolution reaction, and the results are as follows: Figure 5As shown, nickel diselenide hierarchical nanoneedle self-supporting catalysts rich in nickel vacancies exhibit excellent hydrogen evolution performance. Example 4

[0035] 5 mmol nickel acetylacetone, 2.5 mmol cerium sulfate, 20 mmol urea, and 13.5 mmol ammonium fluoride were dissolved in 40 mL of deionized water. After stirring and mixing, the mixture was placed in a reaction vessel with carbon fiber paper and hydrothermally reacted at 250 °C for 5 h. After cooling to room temperature, the carbon fiber paper was removed and washed three times each with water and ethanol, and dried at 80 °C for 24 h to obtain carbon fiber paper loaded with nickel precursor arrays. The carbon fiber paper loaded with nickel precursor arrays was placed in a tube furnace and heated to 900 °C at a rate of 3 °C / min. It was calcined in air at 900 °C for 3 h. After cooling to room temperature, it was washed three times each with water and ethanol, and dried at 80 °C for 24 h to obtain carbon fiber paper loaded with nickel oxide hierarchical nanoneedle arrays. The carbon fiber paper loaded with nickel oxide hierarchical nanoneedle arrays was then reacted with 30 mL of deionized water and 0.98 mol / L... Mix 1 mL of NaHSe solution and hydrothermally react at 200 °C for 6 h. After the reaction is complete, cool to room temperature, remove carbon fiber paper, wash with water and ethanol three times each, and dry at 80 °C for 24 h to obtain nickel diselenide hierarchical nanoneedle array self-supporting catalyst rich in nickel vacancies.

[0036] The nickel-vacancy-rich nickel diselenide hierarchical nanoneedle array self-supporting catalyst prepared in the above examples was applied to the electrocatalytic hydrogen evolution reaction, and the results are as follows: Figure 5 As shown, nickel diselenide hierarchical nanoneedle self-supporting catalysts rich in nickel vacancies exhibit excellent hydrogen evolution performance.

Claims

1. The application of a nickel diselenide hierarchical nanoneedle array self-supporting catalyst in electrocatalytic hydrogen evolution, characterized in that: The nickel diselenide hierarchical nanoneedle array self-supporting catalyst is prepared by dissolving nickel salt, cerium salt, urea, and ammonium fluoride in deionized water and stirring until homogeneous. The mixture is then placed in a reactor with carbon fiber paper for hydrothermal reaction. After the reaction is completed, the mixture is naturally cooled to room temperature, the carbon fiber paper is removed, washed, and dried to obtain carbon fiber paper loaded with nickel precursor array. The carbon fiber paper loaded with nickel precursor array is then calcined in air. After the calcination product is washed and dried, deionized water and NaHSe solution are added, mixed, and then subjected to hydrothermal reaction. After the reaction is completed, the mixture is naturally cooled to room temperature, the carbon fiber paper is removed, washed, and dried to obtain the final product.

2. The method for preparing the nickel diselenide hierarchical nanoneedle array self-supporting catalyst according to claim 1, characterized in that: Nickel salts are selected from nickel chloride, nickel nitrate, and nickel acetylacetone, while cerium salts are selected from cerium nitrate, cerium chloride, and cerium sulfate.

3. The method for preparing the nickel diselenide hierarchical nanoneedle array self-supporting catalyst according to claim 1, characterized in that: The concentrations of nickel salt, cerium salt, urea, and ammonium fluoride in the mixture are 0.01-1 mol / L, 0.01-0.8 mol / L, 0.05-0.5 mol / L, and 0.02-0.5 mol / L, respectively.

4. The method for preparing the nickel diselenide hierarchical nanoneedle array self-supporting catalyst according to claim 1, characterized in that: The hydrothermal reaction temperature is 80-250℃, and the reaction time is 5-48h.

5. The method for preparing the nickel diselenide hierarchical nanoneedle array self-supporting catalyst according to claim 1, characterized in that: Calcine at 400-900℃ for 2-5 hours by increasing the temperature at 1-10℃ / min.

6. The method for preparing the nickel diselenide hierarchical nanoneedle array self-supporting catalyst according to claim 1, characterized in that: The hydrothermal selenization reaction temperature is 80-250℃, the reaction time is 5-48h, and the molar ratio of NaHSe to nickel salt is 1:2-10.

7. The method for preparing the nickel diselenide hierarchical nanoneedle array self-supporting catalyst according to claim 1, characterized in that: The drying temperature is 30-120℃, and the drying time is 1-48 h.

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