A self-supporting cobalt selenide catalyst, a preparation method and application thereof

Abstract

The application provides a self-supporting cobalt selenide catalyst and a preparation method and application thereof, and belongs to the technical field of electrocatalysis, and aims to solve the technical problems of electrode passivation and low conversion efficiency during the decomposition of hydrogen sulfide by an electrochemical method.The preparation method of the self-supporting cobalt selenide catalyst comprises the following steps: (1) preparing a cobalt precursor on a nickel foam substrate by a hydrothermal synthesis method I through a cobalt source; (2) preparing a cobalt selenide by a hydrothermal synthesis method II through a selenium source and the nickel foam loaded with the cobalt precursor prepared in step (1); and (3) preparing a phosphorus-doped cobalt selenide by phosphorus doping of the nickel foam loaded with the cobalt selenide prepared in step (2) by a chemical vapor deposition method.The preparation method is simple and easy to implement, the cost of raw materials is low, the catalyst is not prone to passivation, the catalytic performance is excellent and stable, and the catalyst has excellent hydrogen production and sulfur production performance.

Description

Technical Field

[0001] This invention belongs to the technical field of electrocatalysis, and particularly relates to a self-supporting cobalt selenide catalyst, its preparation method, and its application. Background Technology

[0002] Rapid industrial development has led to the large-scale use of fossil fuels such as oil and natural gas. However, the fossil fuel process generates large amounts of polluting gases such as hydrogen sulfide, exacerbating air pollution. Simultaneously, the depletion of non-renewable energy sources has prompted global efforts to explore sustainable energy alternatives to fossil fuels. Electrochemical desulfurization and hydrogen evolution is a method that kills two birds with one stone, converting hydrogen sulfide into sulfur at the anode while simultaneously generating hydrogen at the cathode.

[0003] The Claus process is a commonly used method for hydrogen sulfide treatment. It primarily involves the incomplete combustion of hydrogen sulfide to produce sulfur dioxide, which then reacts with hydrogen sulfide to produce elemental sulfur and water, thus removing the hydrogen sulfide. However, this method typically requires multiple stages of conversion to achieve a high removal rate, increasing energy consumption and equipment costs. Furthermore, this method directly converts the more valuable hydrogen into water, wasting resources. In contrast to the Claus process, the electrochemical desulfurization and hydrogen evolution process releases hydrogen ions as hydrogen gas from the cathode, avoiding resource waste.

[0004] Water electrolysis is a highly efficient, clean, and high-purity hydrogen production technology. The cathode is the hydrogen evolution reaction (HER), and the anode is the oxygen evolution reaction (OER). The OER is a four-electron proton coupling reaction, and its complex process requires high energy (higher overpotential) to overcome the reaction barrier. Compared to water electrolysis, hydrogen production by electrolyzing hydrogen sulfide requires a lower overpotential and has a more efficient energy utilization rate.

[0005] Although the electrochemical decomposition of hydrogen sulfide has a high energy utilization rate, elemental sulfur adheres to the surface of the electrolytic anode as the reaction proceeds, causing electrode passivation and rapidly reducing conversion efficiency, thus hindering the reaction. Currently, there is a need to develop a high-performance, low-cost, and stable sulfur-repellent electrocatalyst to avoid the problem of anode sulfur deposition and passivation. Summary of the Invention

[0006] To address the technical problems of electrode passivation and low conversion efficiency in the electrochemical decomposition of hydrogen sulfide, this invention proposes a self-supporting cobalt selenide catalyst, its preparation method, and its application. The preparation method is simple and easy to implement, uses low-cost raw materials, is not easily passivated, and exhibits excellent and stable catalytic performance, with superior hydrogen and sulfur production performance.

[0007] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0008] A self-supporting cobalt selenide catalyst, the preparation method of which includes the following steps:

[0009] (1) A cobalt precursor was prepared on a nickel foam substrate by hydrothermal synthesis method I using a cobalt source;

[0010] (2) The selenium source and the foam nickel loaded with cobalt precursor obtained in step (1) are used to prepare cobalt selenide by hydrothermal synthesis method II;

[0011] (3) Phosphorus doping was performed on the nickel foam loaded with cobalt selenide obtained in step (2) by chemical vapor deposition to prepare phosphorus-doped cobalt selenide (P-CoSe / NF).

[0012] In step (1), the hydrothermal synthesis method I is as follows: the cobalt source, precipitant, and ammonium salt are dissolved in solvent I to prepare reaction solution I, and nickel foam is immersed in reaction solution I and reacted at 100-160℃ for 1-24h.

[0013] The cobalt source is one or more of cobalt nitrate, cobalt sulfate, cobalt chloride, and cobalt acetate; the precipitant is urea; the ammonium salt is ammonium fluoride or ammonium nitrate; and the solvent I is water.

[0014] The molar ratio of the cobalt source, precipitant, and ammonium salt is 1:(3-6):(1-3); the concentration of the cobalt source in reaction solution I is 0.05-0.5 mmol / mL.

[0015] In step (2), the hydrothermal synthesis method II is as follows: Selenium source and sodium hydroxide are dissolved in solvent II to prepare reaction solution II, and nickel foam loaded with cobalt precursor is immersed in reaction solution II and reacted at 180-210℃ for 1-24h.

[0016] The selenium source is selenium powder; solvent II is water.

[0017] The molar ratio of the selenium source to sodium hydroxide is 1:(20-30), and the concentration of the selenium source in reaction solution II is 0.05-0.5 mmol / mL.

[0018] In step (3), the chemical vapor deposition method is as follows: a phosphorus source and nickel foam loaded with cobalt selenide are placed in a tube furnace and heated to 400-450°C at a heating rate of 3-10°C / min under an inert gas atmosphere, and held for 1-5 hours; the phosphorus source is sodium dihydrogen phosphate.

[0019] Application of a self-supporting cobalt selenide catalyst in the electrolysis of hydrogen sulfide.

[0020] The beneficial effects of this invention are:

[0021] 1. This invention synthesizes precursors through a highly efficient and simple hydrothermal method. The preparation method is simple, the reaction time is short, and it is easy to industrialize, which has the advantages of being relatively green and economical.

[0022] 2. This invention synthesizes P-CoSe / NF catalysts via vapor deposition. P replaces some Se atoms, causing an overall rightward shift in the XRD peak position of CoSe. The doping of P modulates the local electronic structure, resulting in greater lattice distortion in the original catalyst. This doping effect enhances the catalytic performance of the original catalyst and increases its commercial value.

[0023] 3. The P-CoSe / NF bifunctional electrode of the present invention exhibits excellent catalytic performance in the hydrogen evolution to sulfur production reaction, achieving 100 mA / cm² at a voltage of only 0.35V. -2 The current density is far superior to that of the OER system. This invention achieves a current density of 20 mA / cm². -2 It maintained excellent electrochemical stability for 108 hours during the stability test.

[0024] 4. The P-CoSe / NF bifunctional electrode of the present invention has excellent hydrogen evolution and sulfur production efficiency, with a hydrogen production Faraday efficiency of 97% and a sulfur production rate of 26 mg / h. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 Scanning electron microscope images of CoSe / NF(a) and P-CoSe / NF(b) materials;

[0027] Figure 2 XRD patterns of P-CoSe / NF and CoSe / NF materials;

[0028] Figure 3 Linear voltammetric scan curves and Tafel slope plots of the desulfurization reaction of P-CoSe / NF with a series of comparative materials;

[0029] Figure 4 Linear voltammetric curves and Tafel slope plots of the hydrogen evolution reaction of P-CoSe / NF with a series of comparative materials;

[0030] Figure 5 The sulfur recovery efficiency curve of the dual-electrode system;

[0031] Figure 6 The hydrogen production efficiency curve of the two-electrode system;

[0032] Figure 7 For a two-electrode system at a constant 20 mA / cm -2 Stability curves at current density over 108 hours. Detailed Implementation

[0033] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example 1

[0035] A self-supporting cobalt selenide catalyst, the preparation method of which includes the following steps:

[0036] (1). Cut the nickel foam (NF) into fixed sizes and sonicate it in 3 mol / L HCl solution, ethanol, and deionized water for 15 min to remove impurities from the NF surface.

[0037] (2) Dissolve 5 mmol CoCl2·6H2O, 20 mmol urea, and 10 mmol ammonium fluoride in 50 mL of deionized water and stir for 1 h until the solution is completely dissolved. Transfer 35 mL to a reaction vessel and immerse NF in it. Keep it in a drying oven at 120 °C for 7 h. After cooling to room temperature, wash it several times with ethanol and deionized water, and dry it in a vacuum oven at 60 °C for more than 6 h to prepare NF loaded with cobalt precursor.

[0038] (3) Dissolve 3 mmol Se powder and 70 mmol NaOH in 30 mL of deionized water and stir continuously. Transfer the solution to a reaction vessel and immerse the NF loaded with the cobalt precursor in it. Keep it at 210 °C for 12 h. Finally, wash with ethanol and deionized water and dry at 60 °C for more than 6 h to prepare NF loaded with CoSe2.

[0039] (4) Place NF loaded with CoSe2 and 0.25g NaH2PO2·H2O on a ceramic boat and calcine it in a tube furnace under an inert gas atmosphere at a heating rate of 5℃ / min. The gas pressure in the tube furnace is maintained at about 0MPa, the flow rate is 90mL / min, the reaction temperature is 450℃, and the holding time is 3h to generate P-CoSe / NF catalyst.

[0040] Example 2

[0041] A self-supporting cobalt selenide catalyst, the preparation method of which includes the following steps:

[0042] (1). Cut the nickel foam (NF) into fixed sizes and sonicate it in 3 mol / L HCl solution, ethanol, and deionized water for 15 min to remove impurities from the NF surface.

[0043] (2) Dissolve 5 mmol CoCl2·6H2O, 20 mmol urea, and 10 mmol ammonium fluoride in 50 mL of deionized water and stir for 1 h until the solution is completely dissolved. Transfer 35 mL to a reaction vessel and immerse NF in it. Keep it in a drying oven at 120 °C for 7 h. After cooling to room temperature, wash it several times with ethanol and deionized water, and dry it in a vacuum oven at 60 °C for more than 6 h to prepare NF loaded with cobalt precursor.

[0044] (3) Dissolve 3 mmol Se powder and 70 mmol NaOH in 30 mL of deionized water and stir continuously. Transfer the solution to a reaction vessel and immerse the NF loaded with the cobalt precursor in it. Keep it at 210 °C for 12 h. Finally, wash with ethanol and deionized water and dry at 60 °C for more than 6 h to prepare NF loaded with CoSe2.

[0045] (4) Place NF loaded with CoSe2 and 0.25g NaH2PO2·H2O on a ceramic boat and calcine it in a tube furnace under an inert gas atmosphere at a heating rate of 5℃ / min. The gas pressure in the tube furnace is maintained at about 0MPa, the flow rate is 90mL / min, the reaction temperature is 450℃, and the holding time is 1h to generate P-CoSe / NF catalyst.

[0046] Example 3

[0047] A self-supporting cobalt selenide catalyst, the preparation method of which includes the following steps:

[0048] (1). Cut the nickel foam (NF) into fixed sizes and sonicate it in 3 mol / L HCl solution, ethanol, and deionized water for 15 min to remove impurities from the NF surface.

[0049] (2) Dissolve 5 mmol CoCl2·6H2O, 20 mmol urea, and 10 mmol ammonium fluoride in 50 mL of deionized water and stir for 1 h until the solution is completely dissolved. Transfer 35 mL to a reaction vessel and immerse NF in it. Keep it in a drying oven at 120 °C for 7 h. After cooling to room temperature, wash it several times with ethanol and deionized water, and dry it in a vacuum oven at 60 °C for more than 6 h to prepare NF loaded with cobalt precursor.

[0050] (3) Dissolve 3 mmol Se powder and 70 mmol NaOH in 30 mL of deionized water and stir continuously. Transfer the solution to a reaction vessel and immerse the NF loaded with the cobalt precursor in it. Keep it at 210 °C for 12 h. Finally, wash with ethanol and deionized water and dry at 60 °C for more than 6 h to prepare NF loaded with CoSe2.

[0051] (4) Place NF loaded with CoSe2 and 0.25g NaH2PO2·H2O on a ceramic boat and calcine it in a tube furnace under an inert gas atmosphere at a heating rate of 5℃ / min. The gas pressure in the tube furnace is maintained at about 0MPa, the flow rate is 90mL / min, the reaction temperature is 450℃, and the holding time is 2h to generate P-CoSe / NF catalyst.

[0052] Example 4

[0053] A self-supporting cobalt selenide catalyst, the preparation method of which includes the following steps:

[0054] (1). Cut the nickel foam (NF) into fixed sizes and sonicate it in 3 mol / L HCl solution, ethanol, and deionized water for 15 min to remove impurities from the NF surface.

[0055] (2) Dissolve 5 mmol CoCl2·6H2O, 20 mmol urea, and 10 mmol ammonium fluoride in 50 mL of deionized water and stir for 1 h until the solution is completely dissolved. Transfer 35 mL to a reaction vessel and immerse NF in it. Keep it in a drying oven at 120 °C for 7 h. After cooling to room temperature, wash it several times with ethanol and deionized water, and dry it in a vacuum oven at 60 °C for more than 6 h to prepare NF loaded with cobalt precursor.

[0056] (3) Dissolve 3 mmol Se powder and 70 mmol NaOH in 30 mL of deionized water and stir continuously. Transfer the solution to a reaction vessel and immerse the NF loaded with the cobalt precursor in it. Keep it at 210 °C for 12 h. Finally, wash with ethanol and deionized water and dry at 60 °C for more than 6 h to prepare NF loaded with CoSe2.

[0057] (4) Place NF loaded with CoSe2 and 0.25g NaH2PO2·H2O on a ceramic boat and calcine it in a tube furnace under an inert gas atmosphere at a heating rate of 5℃ / min. The gas pressure in the tube furnace is maintained at about 0MPa, the flow rate is 90mL / min, the reaction temperature is 450℃, and the holding time is 4h to generate P-CoSe / NF catalyst.

[0058] Example 5

[0059] A self-supporting cobalt selenide catalyst, the preparation method of which includes the following steps:

[0060] (1). Cut the nickel foam (NF) into fixed sizes and sonicate it in 3 mol / L HCl solution, ethanol, and deionized water for 15 min to remove impurities from the NF surface.

[0061] (2) Dissolve 5 mmol CoCl2·6H2O, 20 mmol urea, and 10 mmol ammonium fluoride in 50 mL of deionized water and stir for 1 h until the solution is completely dissolved. Transfer 35 mL to a reaction vessel and immerse NF in it. Keep it in a drying oven at 120 °C for 7 h. After cooling to room temperature, wash it several times with ethanol and deionized water, and dry it in a vacuum oven at 60 °C for more than 6 h to prepare NF loaded with cobalt precursor.

[0062] (3) Dissolve 3 mmol Se powder and 70 mmol NaOH in 30 mL of deionized water and stir continuously. Transfer the solution to a reaction vessel and immerse the NF loaded with the cobalt precursor in it. Keep it at 210 °C for 12 h. Finally, wash with ethanol and deionized water and dry at 60 °C for more than 6 h to prepare NF loaded with CoSe2.

[0063] (4) Place NF loaded with CoSe2 and 0.25g NaH2PO2·H2O on a ceramic boat and calcine it in a tube furnace under an inert gas atmosphere at a heating rate of 5℃ / min. The gas pressure in the tube furnace is maintained at about 0MPa, the flow rate is 90mL / min, the reaction temperature is 450℃, and the holding time is 5h to generate P-CoSe / NF catalyst.

[0064] Example 6

[0065] A self-supporting cobalt selenide catalyst, the preparation method of which includes the following steps:

[0066] (1). Cut the nickel foam (NF) into fixed sizes and sonicate it in 3 mol / L HCl solution, ethanol, and deionized water for 15 min to remove impurities from the NF surface.

[0067] (2) Dissolve 5 mmol CoCl2·6H2O, 20 mmol urea, and 10 mmol ammonium fluoride in 50 mL of deionized water and stir for 1 h until the solution is completely dissolved. Transfer 35 mL to a reaction vessel and immerse NF in it. Keep it in a drying oven at 120 °C for 7 h. After cooling to room temperature, wash it several times with ethanol and deionized water, and dry it in a vacuum oven at 60 °C for more than 6 h to prepare NF loaded with cobalt precursor.

[0068] (3) Dissolve 3 mmol Se powder and 70 mmol NaOH in 30 mL of deionized water and stir continuously. Transfer the solution to a reaction vessel and immerse the NF loaded with the cobalt precursor in it. Keep it at 210 °C for 12 h. Finally, wash with ethanol and deionized water and dry at 60 °C for more than 6 h to prepare NF loaded with CoSe2.

[0069] (4) Place NF loaded with CoSe2 and 0.25g NaH2PO2·H2O on a ceramic boat and calcine it in a tube furnace under an inert gas atmosphere at a heating rate of 5℃ / min. The gas pressure in the tube furnace is maintained at about 0MPa, the flow rate is 90mL / min, the reaction temperature is 400℃, and the holding time is 5h to generate P-CoSe / NF catalyst.

[0070] Example 7

[0071] A self-supporting cobalt selenide catalyst, the preparation method of which includes the following steps:

[0072] (1). Cut the nickel foam (NF) into fixed sizes and sonicate it in 3 mol / L HCl solution, ethanol, and deionized water for 15 min to remove impurities from the NF surface.

[0073] (2) Dissolve 5 mmol CoCl2·6H2O, 15 mmol urea, and 15 mmol ammonium fluoride in 25 mL of deionized water and stir for 1 h until the solution is completely dissolved. Transfer 25 mL to a reaction vessel and immerse NF in it. Keep it in a forced-air drying oven at 160 °C for 1 h. After cooling to room temperature, wash it several times with ethanol and deionized water, and dry it in a vacuum oven at 60 °C for more than 6 h to prepare NF loaded with cobalt precursor.

[0074] (3) Dissolve 3 mmol Se powder and 90 mmol NaOH in 60 mL of deionized water and stir continuously. Transfer the solution to a reaction vessel and immerse the NF loaded with the cobalt precursor in it. Keep it at 180 °C for 24 h. Finally, wash with ethanol and deionized water and dry at 60 °C for more than 6 h to prepare NF loaded with CoSe2.

[0075] (4) Place NF loaded with CoSe2 and 0.25g NaH2PO2·H2O on a ceramic boat and calcine it in a tube furnace under an inert gas atmosphere at a heating rate of 10℃ / min. The gas pressure in the tube furnace is maintained at about 0MPa, the flow rate is 100mL / min, the reaction temperature is 450℃, and the holding time is 1h to generate P-CoSe / NF catalyst.

[0076] Example 8

[0077] A self-supporting cobalt selenide catalyst, the preparation method of which includes the following steps:

[0078] (1). Cut the nickel foam (NF) into fixed sizes and sonicate it in 3 mol / L HCl solution, ethanol, and deionized water for 15 min to remove impurities from the NF surface.

[0079] (2) Dissolve 5 mmol CoCl2·6H2O, 30 mmol urea, and 5 mmol ammonium fluoride in 100 mL of deionized water and stir for 1 h until the solution is completely dissolved. Transfer 35 mL to a reaction vessel and immerse NF in it. Keep it in a drying oven at 100 °C for 24 h. After cooling to room temperature, wash it several times with ethanol and deionized water, and dry it in a vacuum oven at 60 °C for more than 6 h to prepare NF loaded with cobalt precursor.

[0080] (3) Dissolve 3 mmol Se powder and 60 mmol NaOH in 15 mL of deionized water and stir continuously. Transfer the solution to a reaction vessel and immerse the NF loaded with the cobalt precursor in it. Keep it at 200 °C for 1 h. Finally, wash with ethanol and deionized water and dry at 60 °C for more than 6 h to prepare NF loaded with CoSe2.

[0081] (4) Place NF loaded with CoSe2 and 0.25g NaH2PO2·H2O on a ceramic boat and calcine it in a tube furnace under an inert gas atmosphere at a heating rate of 3℃ / min. The gas pressure in the tube furnace is maintained at about 0MPa, the flow rate is 80mL / min, the reaction temperature is 400℃, and the holding time is 5h to generate P-CoSe / NF catalyst.

[0082] Comparative Example 1

[0083] A self-supporting cobalt selenide catalyst, the preparation method of which includes the following steps:

[0084] (1). Cut the nickel foam (NF) into fixed sizes and sonicate it in 3 mol / L HCl solution, ethanol, and deionized water for 15 min to remove impurities from the NF surface.

[0085] (2) Dissolve 5 mmol CoCl2·6H2O, 20 mmol urea, and 10 mmol ammonium fluoride in 50 mL of deionized water and stir for 1 h until the solution is completely dissolved. Transfer 35 mL to a reaction vessel and immerse NF in it. Keep it in a drying oven at 120 °C for 7 h. After cooling to room temperature, wash it several times with ethanol and deionized water, and dry it in a vacuum oven at 60 °C for more than 6 h to prepare NF loaded with cobalt precursor.

[0086] (3) Dissolve 3 mmol Se powder and 70 mmol NaOH in 30 mL of deionized water and stir continuously. Transfer the solution to a reaction vessel and immerse the NF loaded with the cobalt precursor in it. Keep it at 210 °C for 12 h. Finally, wash with ethanol and deionized water and dry at 60 °C for more than 6 h to prepare NF loaded with CoSe2.

[0087] (4) Place the NF loaded with CoSe2 on a ceramic boat and fire it in a tube furnace at a heating rate of 5℃ / min under an inert gas atmosphere. The gas pressure in the tube furnace is maintained at about 0MPa, the flow rate is 90mL / min, the reaction temperature is 450℃, and the holding time is 3h to generate the CoSe / NF catalyst.

[0088] Comparative Example 2

[0089] A self-supporting cobalt selenide catalyst, the preparation method of which includes the following steps:

[0090] (1) Cut the nickel foam (NF) into fixed sizes and sonicate it in 3 mol / L HCl solution, ethanol, and deionized water for 15 min to remove impurities from the NF surface.

[0091] (2) Dissolve 5 mmol CoCl2·6H2O, 20 mmol urea, and 10 mmol ammonium fluoride in 50 mL of deionized water and stir for 1 h until the solution is completely dissolved. Transfer 35 mL to a reaction vessel and immerse NF in it. Keep it in a drying oven at 120 °C for 7 h. After cooling to room temperature, wash it several times with ethanol and deionized water, and dry it in a vacuum oven at 60 °C for more than 6 h to prepare NF loaded with cobalt precursor.

[0092] (3) Dissolve 3 mmol Se powder and 70 mmol NaOH in 30 mL of deionized water and stir continuously. Transfer the solution to a reaction vessel and immerse the NF supported on the cobalt precursor in it. Keep it at 210 °C for 12 h. Finally, wash with ethanol and deionized water and dry at 60 °C for more than 6 h to prepare the CoSe2 / NF supported catalyst.

[0093] Test case

[0094] Figure 1 Scanning electron microscope (SEM) images of CoSe / NF (a) prepared in Comparative Example 1 and P-CoSe / NF (b) prepared in Example 1; from Figure 1 As can be seen from the data, after P doping, CoSe / NF changed from a dendritic shape to a fleshy shape, proving that doping changes its morphology.

[0095] Figure 2XRD patterns of CoSe / NF prepared in Comparative Example 1 and P-CoSe / NF prepared in Example 1; from Figure 2 The diffraction peaks of P-CoSe / NF have shifted relative to CoSe / NF, indicating that P doping plays a regulatory role.

[0096] This experiment uses an H-type electrolytic cell.

[0097] Anode performance testing: P-CoSe / NF prepared in Example 1, CoSe / NF prepared in Comparative Example 1, CoSe2 / NF prepared in Comparative Example 2, and NF were used as working electrodes, with Pt sheets as counter electrodes and Hg / HgO as reference electrodes. A 1.0M NaOH solution was used as the cathode electrolyte, and a 1.0M NaOH + 1.0M Na2S solution was used as the anolyte, separated by a Nafion 117 proton exchange membrane. Before each experiment, high-purity inert gas Ar was introduced into the anolyte chamber for at least 30 minutes. Initial evaluation of the electrocatalytic oxidation performance of H2S was performed using LSV curves at a scan rate of 5 mV / s. -1 During the scanning process, magnetic stirring is applied to make the electrolyte composition more uniform.

[0098] Cathode performance testing: P-CoSe / NF prepared in Example 1, CoSe / NF prepared in Comparative Example 1, CoSe2 / NF prepared in Comparative Example 2, and NF were used as working electrodes, with graphite rods as counter electrodes (because using Pt electrodes in the SOR system would cause irreversible damage to Pt itself), and Hg / HgO as reference electrodes. A 1.0M NaOH solution was used as the cathode electrolyte, and a 1.0M NaOH + 1.0M Na2S solution was used as the anolyte, separated by a Nafion 117 proton exchange membrane. Before each experiment, high-purity inert gas Ar was introduced into the anolyte chamber for at least 30 minutes. Initial evaluation of the electrocatalytic oxidation performance of H2S was performed using LSV curves at a scan rate of 5 mV / s. -1 During the scanning process, magnetic stirring is applied to make the electrolyte composition more uniform.

[0099] Dual-electrode performance testing: Example 1. P-CoSe / NF was prepared and used as the working electrode, with Hg / HgO as the reference electrode. The cathode electrolyte was 1.0M NaOH solution, and the anolyte was 1.0M NaOH + 1.0M Na2S solution, separated by a Nafion 117 proton exchange membrane. Before each experiment, high-purity inert gas Ar was introduced into the anolyte chamber for at least 30 minutes. Initially, LSV curves were used to preliminarily evaluate the electrocatalytic oxidation performance of H2S at a scan rate of 5 mV / s. -1 During the scanning process, magnetic stirring is applied to make the electrolyte composition more uniform.

[0100] Figure 3 The figures (a) and (b) show the linear voltammetric scan curves and Tafel slope plots of the desulfurization reaction of P-CoSe / NF with a series of comparative materials. As can be seen from the figures (a) and (b), P-CoSe / NF improves the efficiency of sulfide removal from solution compared with other catalysts.

[0101] Figure 4 The figures (a) and (b) show the linear voltammetry and Tafel slope of the hydrogen evolution reaction of the invention example P-CoSe / NF with a series of comparative materials. As can be seen from the figures (a) and (b), P-CoSe / NF exhibits superior performance in the hydrogen evolution reaction compared to other catalysts.

[0102] Figure 5 Linear voltammetry curves and Tafel slope plots for the P-CoSe / NF two-electrode system of the invention example: As can be seen from Figures (a) and (b), the SOR system at 100 mA / cm²... -2 The required voltage at the current density is only 0.351V, far lower than the voltage required for OER. At a constant 20mA / cm² current density... -2 Stability curves at current density over 108 hours; As can be seen from the figure, P-CoSe / NF exhibits excellent stability and can maintain a fairly good stability performance in constant current stability tests.

[0103] Figure 6 The figure shows the sulfur recovery efficiency curve of the dual-electrode system in the invention example; it can be seen from the figure that the sulfur yield is maintained at about 26 mg / h.

[0104] Figure 7 The figure shows the hydrogen production efficiency curve of the two-electrode system used in this invention example. It can be seen from the figure that the hydrogen production efficiency is approximately 0.746 mL / min, and the Faraday efficiency is approximately 97%.

[0105] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for preparing a self-supporting cobalt selenide catalyst, characterized in that, Includes the following steps: (1) A cobalt precursor was prepared on a nickel foam substrate by hydrothermal synthesis method I using a cobalt source; (2) The selenium source and the foam nickel loaded with cobalt precursor obtained in step (1) are used to prepare cobalt selenide by hydrothermal synthesis method II; (3) Phosphorus doping was performed on the nickel foam loaded with cobalt selenide obtained in step (2) by chemical vapor deposition to prepare phosphorus-doped cobalt selenide.

2. The method for preparing the self-supported cobalt selenide catalyst according to claim 1, characterized in that, In step (1), the hydrothermal synthesis method I is as follows: the cobalt source, precipitant, and ammonium salt are dissolved in solvent I to prepare reaction solution I, and nickel foam is immersed in reaction solution I and reacted at 100-160℃ for 1-24h.

3. The method for preparing the self-supported cobalt selenide catalyst according to claim 2, characterized in that, The cobalt source is one or more of cobalt nitrate, cobalt sulfate, cobalt chloride, and cobalt acetate; the precipitant is urea; the ammonium salt is ammonium fluoride or ammonium nitrate; and the solvent I is water.

4. The method for preparing the self-supporting cobalt selenide catalyst according to claim 3, characterized in that, The molar ratio of the cobalt source, precipitant, and ammonium salt is 1:(3-6):(1-3); the concentration of the cobalt source in reaction solution I is 0.05-0.5 mmol / mL.

5. The method for preparing the self-supporting cobalt selenide catalyst according to any one of claims 1-4, characterized in that, In step (2), the hydrothermal synthesis method II is as follows: Selenium source and sodium hydroxide are dissolved in solvent II to prepare reaction solution II, and nickel foam loaded with cobalt precursor is immersed in reaction solution II and reacted at 180-210℃ for 1-24h.

6. The method for preparing the self-supporting cobalt selenide catalyst according to claim 5, characterized in that, The selenium source is selenium powder; solvent II is water.

7. The method for preparing the self-supported cobalt selenide catalyst according to claim 6, characterized in that, The molar ratio of the selenium source to sodium hydroxide is 1:(20-30), and the concentration of the selenium source in reaction solution II is 0.05-0.5 mmol / mL.

8. The method for preparing the self-supported cobalt selenide catalyst according to claim 1, characterized in that, In step (3), the chemical vapor deposition method is as follows: a phosphorus source and nickel foam loaded with cobalt selenide are placed in a tube furnace, and under an inert gas atmosphere, the flow rate is 80-100 mL / min, the temperature is raised to 400-450℃ at a heating rate of 3-10℃ / min, and the holding time is 1-5h; the phosphorus source is sodium dihydrogen phosphate.

9. A self-supporting cobalt selenide catalyst prepared by any one of claims 1-8.

10. The application of the self-supporting cobalt selenide catalyst of claim 9 in the electrolysis of hydrogen sulfide.

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