Bi2S3 / Cu2S / CF foam metal, preparation method, nitrogen fixation device and nitrogen fixation method

Abstract

The invention belongs to the field of nitrogen fixation catalysts, and discloses Bi2S3 / Cu2S / CF foam metal, a preparation method, a nitrogen fixation device and a nitrogen fixation method. The preparation method of the Bi2S3 / Cu2S / CF foam metal comprises the following steps: dissolving Bi (NO3) 3.5 H2O and thioacetamide in a mixed solution of deionized water and ethylene glycol to obtain a clear solution; putting Cu (OH) 2 / CF and the settled solution into a high-pressure reaction kettle, heating, and washing with deionized water and absolute ethyl alcohol; and drying in vacuum to obtain the Bi2S3 / Cu2S / CF foam metal. Under the synergistic effect of Cu2S and Bi2S3, the utilization range of light is widened, under the illumination condition, by applying proper voltage, the material generates electron-hole separation, carrier recombination is effectively reduced, oxidation and reduction reactions are separated in space, oxidation of ammonia nitrogen is inhibited, the selectivity of reaction products is improved, and by-product reactions and hydrogen evolution reactions are inhibited, so that the photoelectric conversion efficiency is improved. Therefore, the yield of ammonia nitrogen and the utilization efficiency of photoelectricity are remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of nitrogen fixation catalysts, in particular to a Bi2S3 / Cu2S / CF foam metal, a preparation method, a nitrogen fixation device and a method thereof. BACKGROUND

[0002] Ammonia (NH3) as a chemical raw material and clean energy supplier plays an important role in industry and agriculture. About 78% of atmospheric compounds are nitrogen, which can be generated under the combined action of photochemistry and electrochemistry. The nitrogen fixation reaction using sunlight and low voltage can effectively reduce energy consumption and carbon dioxide emissions, and can effectively alleviate the production problems existing in the modern H-B nitrogen fixation ammonia production industry.

[0003] Both photocatalytic and electrocatalytic nitrogen fixation have their drawbacks. Photocatalytic nitrogen fixation mainly uses sunlight to irradiate the catalyst to generate electron holes for redox reaction, but the high recombination rate of photo-generated carriers and low light utilization rate affect the occurrence of photocatalytic nitrogen fixation reaction; and in the electrocatalytic nitrogen fixation reaction, the high energy barrier of nitrogen activation and hydrogen evolution reaction needs to be considered, and the activity and selectivity of the process are poor, thus resulting in low faradic efficiency. In summary, the efficiency of the existing technology for photocatalytic and electrocatalytic nitrogen fixation reaction is low. SUMMARY

[0004] The main purpose of the present application is to provide a Bi2S3 / Cu2S / CF foam metal photoelectric nitrogen fixation catalyst, a preparation method and a nitrogen fixation method thereof, which aims to solve the problem of low efficiency of photocatalytic and electrocatalytic nitrogen fixation reaction.

[0005] To achieve the above-mentioned purpose, the present application provides a preparation method of Bi2S3 / Cu2S / CF foam metal, characterized in that it comprises the following steps:

[0006] Dissolve Bi(NO3)3·5H2O and thioacetamide in a mixed solution of deionized water and ethylene glycol to obtain a clear solution;

[0007] After heating in a high-pressure reaction kettle, wash with deionized water and anhydrous ethanol;

[0008] Vacuum drying to obtain Bi2S3 / Cu2S / CF foam metal.

[0009] In an embodiment, the amount of Bi(NO3)3·5H2O is (0.25-1) mmol, and the amount of thioacetamide is 0.3 g.

[0010] In one embodiment, the heating temperature of the clarified solution and the Cu(OH)2 / CF is 100~150°C, and the heating time is 10~16 hours.

[0011] In one embodiment, the preparation method of Cu(OH)2 / CF includes:

[0012] Wash the foamed copper with hydrochloric acid, ethanol, and deionized water respectively, and dry it for later use.

[0013] Sodium hydroxide is dissolved in deionized water to obtain solution A;

[0014] Ammonium persulfate was dissolved in deionized water to obtain solution B;

[0015] Mix and stir the solutions A and B thoroughly to obtain a mixed solution;

[0016] The copper foam was immersed and stirred in the mixed solution;

[0017] The copper foam was washed with deionized water and anhydrous ethanol and then vacuum dried to obtain the Cu(OH)2 / CF.

[0018] The present invention also provides a Bi2S3 / Cu2S / CF foam metal, which is a Bi2S3 / Cu2S / CF foam metal obtained according to the preparation method of Bi2S3 / Cu2S / CF foam metal according to any one of the above claims.

[0019] The present invention also provides a nitrogen fixation device, comprising:

[0020] An H-type two-cell reaction system includes a cathode chamber, an anode chamber, and a Nafion membrane disposed between the cathode chamber and the anode chamber; and...

[0021] The three-electrode system includes a reference electrode and a working electrode disposed in the anode chamber and a counter electrode disposed in the cathode chamber. The material of the reference electrode is Ag / AgCl, the material of the counter electrode is Pt, and the working electrode is the aforementioned Bi2S3 / Cu2S / CF foam metal.

[0022] In one embodiment, the method for processing the Nafion membrane includes:

[0023] The initial Nafion membrane was heated in a water bath for 1 hour in 5% H2O2, deionized water, 0.5M H2SO4 solution and deionized water, respectively.

[0024] The initial Nafion membrane was immersed in deionized water at room temperature and washed to obtain the Nafion membrane.

[0025] The present invention also provides a nitrogen fixation method for a nitrogen fixation device, comprising:

[0026] Before starting the nitrogen fixation reaction, N2 is introduced into the anode and cathode chambers to remove other gases dissolved in the water.

[0027] During the nitrogen fixation reaction, N2 is continuously introduced at room temperature, and a xenon lamp is turned on to apply a bias voltage to carry out the photoelectrocatalytic synthesis of ammonia.

[0028] This invention provides a Bi₂S₃ / Cu₂S / CF foam metal, directly using copper foam as a catalyst support to synthesize Cu₂S rod-like structures on the copper foam, which can significantly improve the conductivity of the electrode material. The high porosity and large specific surface area of ​​the copper foam also provide a large active surface for nitrogen fixation and mass transport. The synergistic effect of Cu₂S and Bi₂S₃ broadens the range of light utilization. Under illumination, by applying an appropriate voltage, electron-hole separation is induced in the material, effectively reducing carrier recombination and spatially separating oxidation and reduction reactions. This inhibits the oxidation of ammonia nitrogen, improves the selectivity of reaction products, suppresses by-product reactions and hydrogen evolution reactions, thereby significantly improving the yield of ammonia nitrogen and the photoelectric utilization efficiency. Attached Figure Description

[0029] Figure 1 These are scanning electron microscope (SEM) images (a) of Cu(OH)2 / CF obtained in Example 1 of the present invention and (b) of Bi2S3 / Cu2S / CF foam metal material obtained in Example 3 of the present invention.

[0030] Figure 2 These are the XRD patterns of Bi2S3 / Cu2S / CF and Bi2S3 / Cu2S / CF in Examples 1 to 8 of the present invention;

[0031] Figure 3 This is a schematic diagram of the reaction principle of the nitrogen fixation device provided by the present invention;

[0032] Figure 4 This is the ammonia nitrogen standard curve measured in this invention: the Nessler method standard curve;

[0033] Figure 5 The graph shows the photoelectrochemical nitrogen fixation performance and Faradaic efficiency of Bi2S3 / Cu2S / CF (BiCuS-1, BiCuS-2, BiCuS-3, BiCuS-4) prepared in Examples 1, 2, 3, and 4 at preset potentials and the material in Example 3 at different potentials.

[0034] Figure 6 The graph shows the photoelectrochemical nitrogen fixation cycle performance of the Bi2S3 / Cu2S / CF material prepared in Example 3 at a preset potential;

[0035] Figure 7The UV-Vis diffuse reflectance spectra of the Bi2S3 / Cu2S / CF foam metal material obtained in Example 3 are shown.

[0036] Figure 8 This is a linear scanning voltammetry diagram of the Bi2S3 / Cu2S / CF material obtained in Example 3;

[0037] Figure 9 The low-temperature in-situ electron spin resonance test diagrams of Bi2S3 / Cu2S / CF and Cu2S / CF obtained in Example 3 are shown.

[0038] Figure 10 The nitrogen chemisorption diagrams for Bi2S3 / Cu2S / CF and Cu2S / CF obtained in Example 3 are shown.

[0039] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0040] 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 a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0041] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0042] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the meaning of "and / or" throughout the text includes three parallel solutions; for example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0043] This invention provides a method for preparing Bi2S3 / Cu2S / CF foam metal, comprising the following steps:

[0044] S10. Dissolve Bi(NO3)3·5H2O and thioacetamide in a mixed solution of deionized water and ethylene glycol to obtain a clear solution;

[0045] S20. After heating Cu(OH)2 / CF and the clarified solution in a high-pressure reactor, wash with deionized water and anhydrous ethanol.

[0046] S30, vacuum drying to obtain Bi2S3 / Cu2S / CF foam metal.

[0047] This invention provides a Bi₂S₃ / Cu₂S / CF foam metal, directly using copper foam as a catalyst support to synthesize Cu₂S rod-like structures on the copper foam, which can significantly improve the conductivity of the electrode material. The high porosity and large specific surface area of ​​the copper foam also provide a large active surface for nitrogen fixation and mass transport. The synergistic effect of Cu₂S and Bi₂S₃ broadens the range of light utilization. Under illumination, by applying an appropriate voltage, electron-hole separation is induced in the material, effectively reducing carrier recombination and spatially separating oxidation and reduction reactions. This inhibits the oxidation of ammonia nitrogen, improves the selectivity of reaction products, suppresses by-product reactions and hydrogen evolution reactions, thereby significantly improving the yield of ammonia nitrogen and the photoelectric utilization efficiency.

[0048] EPR testing showed that sulfur vacancies were successfully created on the catalyst, and the intensity of sulfur vacancies on Bi2S3 / Cu2S / CF was higher than that on Cu2S / CF.

[0049] Nitrogen TPD analysis revealed that sulfur vacancies play a crucial role in the chemisorption and activation of N2 molecules. In the presence of sulfur vacancies, N2 can be chemisorbed and activated by photogenerated electrons, achieving powerful photocatalytic nitrogen fixation performance.

[0050] This invention tested the photoelectrocatalytic nitrogen fixation performance of Bi2S3 / Cu2S / CF foam metal materials with different Bi2S3 content ratios under various voltages, determining the optimal nitrogen fixation performance, Faradaic efficiency, and voltage value. Compared with other photocatalytic and electrocatalytic nitrogen fixation performances, it also shows a certain improvement. Furthermore, the composite catalyst possesses characteristics such as good stability, reusability, simple operation, and easy availability.

[0051] Specifically, in this embodiment, the amount of Bi(NO3)3·5H2O is (0.25~1) mmol, and the amount of thioacetamide is 0.3g.

[0052] Similarly, in this embodiment, the heating temperature of the clarified solution and the Cu(OH)2 / CF is 100~150℃, and the heating time is 10~16 hours.

[0053] On the other hand, the preparation method of Cu(OH)2 / CF includes:

[0054] S01. Wash the treated foamed copper with hydrochloric acid, ethanol, and deionized water respectively, and dry it for later use.

[0055] S02. Dissolve sodium hydroxide in deionized water to obtain solution A;

[0056] S03. Dissolve ammonium persulfate in deionized water to obtain solution B;

[0057] S04. Mix and stir the solution A and the solution B to obtain a mixed solution;

[0058] S05. Soak and stir the foamed copper in the mixed solution;

[0059] S06. The foamed copper was washed several times with deionized water and anhydrous ethanol, and then vacuum dried to obtain Cu(OH)2 / CF.

[0060] It should be noted that, in this embodiment, the copper foam needs to be cut into 1×2cm pieces. 2 Size.

[0061] Based on the above-described method for preparing Bi2S3 / Cu2S / CF foam metal, this invention also provides a Bi2S3 / Cu2S / CF foam metal, which includes all the technical features of the Bi2S3 / Cu2S / CF foam metal obtained by the above-described method for preparing Bi2S3 / Cu2S / CF foam metal, and therefore also has the technical effects brought about by all the above-described technical features, which will not be elaborated here.

[0062] Based on the above-mentioned Bi2S3 / Cu2S / CF foam metal, the present invention also provides a nitrogen fixation device, comprising:

[0063] An H-type two-cell reaction system includes a cathode chamber, an anode chamber, and a Nafion membrane disposed between the cathode chamber and the anode chamber; and...

[0064] The three-electrode system includes a reference electrode and a working electrode disposed in the anode chamber and a counter electrode disposed in the cathode chamber. The material of the reference electrode is Ag / AgCl, the material of the counter electrode is Pt, and the working electrode is Bi2S3 / Cu2S / CF foam metal as a photoelectric nitrogen fixation catalyst according to claim 5.

[0065] Furthermore, the method for processing the Nafion membrane includes:

[0066] The initial Nafion membrane was heated in a water bath sequentially in H2O2, deionized water, H2SO4 solution and deionized water;

[0067] The Nafion membrane was obtained by immersing it in deionized water at room temperature.

[0068] The present invention also provides a nitrogen fixation method for a nitrogen fixation device, comprising:

[0069] Before starting the nitrogen fixation reaction, N2 is introduced into the anode and cathode chambers to remove other gases dissolved in the water.

[0070] In this embodiment, N2 is introduced into the anode chamber and cathode chamber at a flow rate of 100 sccm for 30 minutes.

[0071] During the nitrogen fixation reaction, N2 is continuously introduced at room temperature, a xenon lamp is turned on, a bias voltage is applied, and the photoelectrocatalytic synthesis of ammonia is carried out.

[0072] In this embodiment, the flow rate of N2 is 50~80 sccm.

[0073] The following are specific embodiments provided by the present invention:

[0074] Example 1

[0075] (1) Preparation of Cu(OH)2 / CF foam metal material: Cut the copper foam into pieces with a size of 1×2cm 2 The copper foam was washed several times with hydrochloric acid, ethanol, and deionized water, and then dried at room temperature. 3.2 g of sodium hydroxide was dissolved in 22 ml of deionized water, and 0.89 g of ammonium persulfate was dissolved in 8 ml of deionized water. The two solutions were then mixed thoroughly. The treated copper foam was immersed in the mixed solution and stirred for 30 minutes. It was then washed several times with deionized water and anhydrous ethanol, and then dried under vacuum at 60°C overnight.

[0076] The Cu(OH)2 / CF foam metal was characterized using scanning electron microscopy (SEM) and XRD, such as... Figure 1 (a) and Figure 2 As shown in (Cu(OH)2 / CF), Cu(OH)2 grows in a fibrous manner on copper foam.

[0077] (2) Preparation of Bi2S3 / Cu2S / CF foam metal material: 0.25 mmol of Bi(NO3)3·5H2O and 0.3 g of thioacetamide were completely dissolved in a mixed solution of 25 mL of deionized water and 25 mL of ethylene glycol to obtain a clear solution. Cu(OH)2 / CF and the solution were placed in a high-pressure reactor and heated at 120 °C for 12 h. After washing with deionized water and anhydrous ethanol, the mixture was then vacuum dried overnight at 60 °C to obtain Bi2S3 / Cu2S / CF foam metal material, denoted as BiCuS-1.

[0078] BiCuS-1 was characterized using XRD, such as... Figure 2 As shown in (BiCuS-1).

[0079] Example 2

[0080] (1) The preparation of Cu(OH)2 / CF foam metal material is the same as in Example 1.

[0081] (2) The preparation process of the Bi2S3 / Cu2S / CF foam metal material is the same as in Example 1, except that Bi(NO3)3·5H2O is 0.50 mmol. The resulting Bi2S3 / Cu2S / CF foam metal material is denoted as BiCuS-2.

[0082] BiCuS-2 was characterized using XRD, such as... Figure 2 As shown in (BiCuS-2).

[0083] Example 3

[0084] (1) The preparation of Cu(OH)2 / CF is the same as in Example 1.

[0085] (2) The preparation process of Bi2S3 / Cu2S / CF foam metal material is the same as in Example 1, except that Bi(NO3)3·5H2O is 0.75 mmol. The resulting Bi2S3 / Cu2S / CF foam metal material is denoted as BiCuS-3.

[0086] BiCuS-3 was characterized using scanning electron microscopy (SEM) and XRD, such as... Figure 1 (b) Figure 2 As shown in (BiCuS-3), the SEM image reveals that the Bi2S3 / Cu2S / CF foam metal material consists of 3D Bi2S3 embedded in rod-shaped Cu2S / CF.

[0087] Example 4

[0088] (1) The preparation of Cu(OH)2 / CF is the same as in Example 1.

[0089] (2) The process for producing the Bi2S3 / Cu2S / CF foam metal material is the same as in Example 1, except that Bi(NO3)3·5H2O is 1.00 mmol. The resulting Bi2S3 / Cu2S / CF foam metal material is denoted as BiCuS-4.

[0090] BiCuS-3 was characterized using XRD, such as... Figure 2 As shown in (BiCuS-4).

[0091] Example 5

[0092] (1) The preparation of Cu(OH)2 / CF is the same as in Example 1.

[0093] (2) The preparation process of Bi2S3 / Cu2S / CF foam metal material is the same as in Example 1, except that Bi(NO3)3·5H2O is 0.75 mmol. The high-pressure reactor is heated to 100℃ for 16 hours. The resulting Bi2S3 / Cu2S / CF foam metal material is denoted as BiCuS-5.

[0094] MoCu-5 was characterized using XRD, such as... Figure 2 As shown in (BiCuS-5).

[0095] Example 6

[0096] (1) The preparation of Cu(OH)2 / CF is the same as in Example 1.

[0097] (2) The preparation process of Bi2S3 / Cu2S / CF foam metal material is the same as in Example 1, except that Bi(NO3)3·5H2O is 0.75 mmol. The high-pressure reactor is heated to 130℃ for 14 hours. The resulting Bi2S3 / Cu2S / CF foam metal material is denoted as BiCuS-6.

[0098] MoCu-6 was characterized using XRD, such as... Figure 2 As shown in (BiCuS-6).

[0099] Example 7

[0100] (1) The preparation of Cu(OH)2 / CF is the same as in Example 1.

[0101] (2) The preparation process of Bi2S3 / Cu2S / CF foam metal material is the same as in Example 1, except that Bi(NO3)3·5H2O is 0.75 mmol. The high-pressure reactor is heated to 150℃ for 10 hours. The resulting Bi2S3 / Cu2S / CF foam metal material is denoted as BiCuS-7.

[0102] MoCu-7 was characterized using XRD, such as... Figure 2 As shown in (MoCu-7).

[0103] Example 8

[0104] (1) The preparation of Cu(OH)2 / CF is the same as in Example 1.

[0105] (2) The preparation process of Bi2S3 / Cu2S / CF foam metal material is the same as in Example 1, except that Bi(NO3)3·5H2O is 0.75 mmol. The high-pressure reactor is heated to 100℃ for 12 hours. The resulting Bi2S3 / Cu2S / CF foam metal material is denoted as BiCuS-8.

[0106] BiCuS-8 was characterized using XRD, such as... Figure 2 As shown in (BiCuS-8).

[0107] For comparison, the present invention also prepared pure Cu2S / CF, specifically by cutting copper foam into pieces of 1×2cm size. 2 Wash the sample several times with hydrochloric acid, ethanol, and deionized water, and then dry it at room temperature for later use. Dissolve 0.89 g of ammonium persulfate in 8 ml of deionized water, and then dissolve 3.2 g of sodium hydroxide in 22 ml of deionized water. Mix the two solutions thoroughly.

[0108] The cleaned copper foam was soaked in the mixed solution for 30 minutes. Then it was washed several times with deionized water and anhydrous ethanol, and then vacuum dried overnight at 60°C to obtain Cu(OH)2 / CF.

[0109] Then, Cu(OH)2 / CF and 0.3g of thioacetamide were placed in a mixed solution of 25mL deionized water and 25mL ethylene glycol, transferred to a high-pressure reactor, and heated at 120℃ for 12h.

[0110] After natural cooling, the material was washed several times with deionized water and anhydrous ethanol, and then vacuum dried overnight at 60°C to obtain Cu2S / CF material. XRD characterization was then performed. Figure 2 As shown.

[0111] Simultaneously, pure Bi₂S₃ powder was prepared. The specific procedure was as follows: 0.75 mmol Bi(NO₃)₃·5H₂O and 0.3 g thioacetamide were dissolved in a mixed solution of 25 mL deionized water and 25 mL ethylene glycol. The solution was transferred to a high-pressure reactor and maintained at 120 °C for 12 hours. After cooling, the product was collected by filtration, washed 3-5 times with deionized water and anhydrous ethanol, and then vacuum dried overnight at 60 °C to obtain Bi₂S₃ powder. XRD characterization was performed, as shown below. Figure 2 As shown.

[0112] This invention also provides the application of Bi2S3 / Cu2S / CF foam metal materials in photoelectrocatalytic nitrogen fixation.

[0113] Bi2S3 / Cu2S / CF and Cu2S / CF samples from Examples 1, 2, 3, and 4 were selected for photoelectrochemical nitrogen fixation performance experiments.

[0114] The photoelectrochemical nitrogen fixation experiment specifically employed a three-electrode system. The reactor was a two-cell reaction system, with a Nafion membrane separating the cathode and anode chambers. Ag / AgCl was used as the reference electrode, a Pt sheet as the counter electrode, and the steric material directly as the working electrode. A 300W xenon lamp was used as the light source, and 0.1M Na₂SO₄ solution was used as the electrolyte solution. All potentials measured during the experiment were calibrated to RHE using the Nernst equation: RHE = E Ag / AgCl +0.197 +0.059 pH. The reaction apparatus system and principle are as follows: Figure 3 .

[0115] Pretreatment of Nafion membranes: The membranes were heated in a water bath for 1 hour in 5% H2O2, deionized water, 0.5M H2SO4 solution and deionized water respectively, and then rinsed in deionized water at room temperature for later use.

[0116] The ammonia nitrogen detection method used in the experiment was the Nessler spectrophotometric method. The Nessler method is based on the People's Republic of China National Environmental Protection Standard HJ533-2009. The standard curve was plotted as follows: Figure 4 : Nessler's standard curve.

[0117] Before the nitrogen fixation reaction, high-purity N2 was introduced into the anode and cathode electrolytes at a flow rate of 100 sccm for 30 min to remove dissolved oxygen in the water. During the nitrogen fixation reaction, high-purity nitrogen was continuously introduced at a flow rate of 100 mL / min while maintaining room temperature. A bias voltage (-0.4~-0.8V) was applied, and a 300W xenon lamp was turned on at the same time to carry out the photoelectrochemical synthesis of ammonia.

[0118] Its nitrogen fixation performance is as follows Figure 5 As shown, BiCuS-3 exhibits the best photoelectrochemical nitrogen fixation effect. Under illumination and a voltage of -0.6V, it demonstrates the highest nitrogen fixation efficiency and Faraday efficiency, approximately 29.84 μmol·h⁻¹. -1 ·cm -2 The efficiency was 21.72%, which improved both the photoelectrochemical nitrogen fixation performance and the Faraday efficiency compared to pure Cu2S / CF.

[0119] This invention also investigated the nitrogen fixation stability of the Bi2S3 / Cu2S / CF foam gold element and material (BiCuS-3) of Example 3, such as...Figure 6 As shown, it still has excellent nitrogen fixation effect after five cycles.

[0120] To investigate the photocatalytic performance of the material, the Bi2S3 / Cu2S / CF foam metal material (BiCuS-3) from Example 3 was selected and subjected to UV-vis spectroscopy testing, such as... Figure 6 As shown, the absorption effect of Bi2S3 in the visible light range is improved after combining with Cu2S / CF. Therefore, the combination of Bi2S3 and Cu2S enhances its absorption and utilization of visible light and improves its photocatalytic performance.

[0121] To investigate the electrocatalytic performance of the material, the Bi2S3 / Cu2S / CF foam metal material (BiCuS-3) from Example 3 was selected for linear sweep voltammetry testing, as shown below. Figure 8 As shown; the specific experimental parameters were: initial potential 0.0V; termination potential -1.0V; scan rate 10mV / s; sampling interval 1mV; nitrogen and argon atmospheres were selected, and gas was continuously introduced into the H-type double-cell reactor at a flow rate of 80mL / min for 30min. Figure 8 It can be seen that the current density on the foam metal is significantly higher under saturated nitrogen conditions than under saturated argon conditions, proving that applying a bias voltage between -1.0 and 0.0V to the material will exhibit certain nitrogen-fixing properties.

[0122] To investigate the surface vacancies in the material, the Bi2S3 / Cu2S / CF foam metal material (BiCuS-3) from Example 3 was selected for low-temperature in-situ electron spin resonance (ESR) testing, such as... Figure 9 As shown, sulfur vacancies are present in Cu₂S / CF and Bi₂S₃ / Cu₂S / CF. The sulfur vacancy intensity in Bi₂S₃ / Cu₂S / CF is relatively higher than that in Cu₂S / CF. The hyperstability of the N≡N bond makes the chemisorption and activation of N₂ molecules crucial in the nitrogen fixation reaction. Therefore, in the presence of sulfur vacancies, N₂ can be chemisorbed and activated by photogenerated electrons, achieving strong catalytic nitrogen fixation performance.

[0123] The effects of sulfur vacancies on the nitrogen adsorption and activation properties of Cu2S / CF and Bi2S3 / Cu2S / CF were further investigated using the N2 temperature programmed desorption (TPD) method. Figure 10 It can be seen that the desorption peak is around 250~350℃, which belongs to N2 chemisorption. Stronger N2 chemisorption is observed in Bi2S3 / Cu2S / CF, indicating that N2 molecules are easily adsorbed and activated on Bi2S3 / Cu2S / CF due to its sulfur-rich vacancies and multiple electron-capturing centers. This provides an effective pathway for electron transfer from the catalyst to N2, effectively promoting the activation of N2 molecules.

[0124] The above are merely preferred embodiments of the present invention and do not limit the scope of the patent. Any equivalent structural or procedural transformations made based on the description and drawings of the present invention, or direct or indirect applications in other related technical fields, are similarly included within the scope of patent protection of the present invention.

Claims

1. A method for preparing Bi2S3 / Cu2S / CF foam metal, characterized in that, Includes the following steps: Bi(NO3)3·5H2O and thioacetamide were dissolved in a mixed solution of deionized water and ethylene glycol to obtain a clear solution; After heating Cu(OH)2 / CF and the clarified solution in a high-pressure reactor, they were washed with deionized water and anhydrous ethanol. Bi2S3 / Cu2S / CF foam metal was obtained by vacuum drying.

2. The method for preparing Bi₂S₃ / Cu₂S / CF foam metal according to claim 1, characterized in that, The amount of Bi(NO3)3·5H2O is (0.25~1) mmol, and the amount of thioacetamide is 0.3g.

3. The method for preparing Bi₂S₃ / Cu₂S / CF foam metal according to claim 1, characterized in that, The clarified solution and the Cu(OH)2 / CF are heated at 100~150℃ for 10~16 hours.

4. The method for preparing Bi₂S₃ / Cu₂S / CF foam metal according to claim 1, characterized in that, The preparation method of Cu(OH)2 / CF includes: Wash the foamed copper with hydrochloric acid, ethanol, and deionized water respectively, and dry it for later use. Sodium hydroxide is dissolved in deionized water to obtain solution A; Ammonium persulfate was dissolved in deionized water to obtain solution B; Mix and stir the solutions A and B thoroughly to obtain a mixed solution; The copper foam was immersed and stirred in the mixed solution; The copper foam was washed with deionized water and anhydrous ethanol and then vacuum dried to obtain the Cu(OH)2 / CF.

5. A Bi₂S₃ / Cu₂S / CF foam metal, characterized in that, The Bi2S3 / Cu2S / CF foam metal is obtained by the preparation method of Bi2S3 / Cu2S / CF foam metal according to any one of claims 1 to 4.

6. A nitrogen fixation device, characterized in that, include: The H-type dual-cell reaction system includes a cathode chamber, an anode chamber, and a Nafion membrane disposed between the cathode chamber and the anode chamber; as well as, The three-electrode system includes a reference electrode and a working electrode disposed in the anode chamber and a counter electrode disposed in the cathode chamber. The material of the reference electrode is Ag / AgCl, the material of the counter electrode is Pt, and the working electrode is the Bi2S3 / Cu2S / CF foam metal as described in claim 5.

7. The nitrogen fixation device according to claim 6, characterized in that, The method for obtaining the Nafion membrane includes: The initial Nafion membrane was heated in a water bath in sequence with H2O2, deionized water, H2SO4 solution and deionized water. The heated initial Nafion membrane was immersed in deionized water at room temperature and washed to obtain the Nafion membrane.

8. The nitrogen fixation method of the nitrogen fixation device according to claim 6, characterized in that, include: Before starting the nitrogen fixation reaction, N2 is introduced into the anode and cathode chambers to remove other gases dissolved in the water. During the nitrogen fixation reaction, N2 is continuously introduced at room temperature, and a xenon lamp is turned on to apply a bias voltage to carry out the photoelectrocatalytic synthesis of ammonia.

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