Application of a cuprous sulfide / tungsten sulfide composite electrocatalyst in electrocatalytic sulfur oxidation reaction

Abstract

This invention prepares a cuprous sulfide / tungsten sulfide composite electrocatalyst (Cu₂S / WS₂) for use in an alkaline electrocatalytic sulfur oxidation coupled with acidic hydrogen production (SOR / / HER) system. Using nickel foam as a support, the Cu₂S / WS₂ / NF composite structure was constructed via a hydrothermal method combined with subsequent electrodeposition and sulfidation treatment. WS₂ provides numerous active sites, while Cu₂S enables effective interfacial modulation, significantly enhancing the catalyst's conductivity and improving its catalytic activity and sulfur poisoning resistance in the electrocatalytic sulfide oxidation reaction (SOR). The catalyst prepared in this invention exhibits excellent electrocatalytic performance and long-term stability in alkaline electrolytes. The preparation method is simple, the synthesis process is highly operable, and it can cleanly and efficiently carry out SOR reactions. 2‑ The conversion method is applicable to energy conversion fields such as hydrogen production from hydrogen sulfide decomposition, showing excellent industrial application prospects and helping to realize the resource recovery of sulfur.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis technology, and specifically discloses a method for preparing and applying a cuprous sulfide / tungsten sulfide composite electrocatalyst. Background Technology

[0002] Hydrogen sulfide (H2S) is widely present in industrial processes such as petroleum refining, natural gas extraction, coking, and wastewater treatment. It is a common toxic sulfide in industrial waste and emissions, causing serious pollution to ecosystems and water resources. In alkaline absorption systems, H2S typically exists as sulfur dioxide (S₂S). 2- Sulfur-containing waste gas or liquid may exist in HS⁻ form. If not handled properly, it can not only harm the ecological environment and human health, but also accelerate the corrosion of metal equipment, increasing operating costs and safety risks. Therefore, achieving efficient purification and resource utilization of sulfur-containing waste gas and liquid is a crucial issue that urgently needs to be addressed in the fields of green chemical engineering and clean energy.

[0003] However, traditional chemical oxidation methods for sulfide recovery, such as the Claus process, microwave catalysts, photochemical reactions, and thermal decomposition, while technically mature, generally suffer from high energy consumption, harsh reaction conditions, easy catalyst deactivation, and complex byproduct separation. In contrast, electrochemical recovery via sulfur oxidation reaction (SOR) is a promising alternative, characterized by high efficiency, low cost, and ease of operation. Furthermore, SOR can be paired with other cathode reactions to further improve process economics.

[0004] Coupled with the sulfur-containing reactive oxygen species (SOR) to the hydrogen evolution reaction (HER) at the cathode, sulfur-containing pollutants can be removed simultaneously, and clean hydrogen energy can be produced. From a thermodynamic perspective, the theoretical reduction potential of SOR (0.142 V vs HER) is significantly lower than that of the oxygen evolution reaction (OER, 1.23 V vs HER), resulting in lower energy consumption on the anode side and making it more conducive to hydrogen production. Simultaneously, it also produces elemental sulfur as an anode product; sulfur is a widely used industrial raw material in fertilizer and rubber manufacturing. In terms of catalytic materials, transition metal sulfides (TMSs) have become the most widely used class of catalysts in the SOR system due to their strong metal-sulfur covalent interactions, tunable electronic structure, and good affinity for sulfur species. (Xia H, Shi Z, Gong C, et al. Recent strategies for activating the basal planes of transition metal dichalcogenides towards hydrogen production[J]. Journal of Materials Chemistry A, 2022, 10(37):19067-19089.) However, single metal sulfides often suffer from limited conductivity, insufficient structural stability, and are prone to sulfur poisoning during long-term operation, which restricts their practical application.

[0005] To address the aforementioned issues, constructing composite systems is considered an effective strategy for improving performance. The cuprous sulfide / tungsten sulfide (Cu2S / WS2) composite material achieves complementary advantages through interfacial coupling. WS2 provides a stable layered framework and abundant edge active sites, while Cu2S possesses high electrical conductivity and excellent sulfur affinity, which helps accelerate electron transport and optimize the adsorption behavior of sulfur species. The two materials form a charge redistribution at the interface, which can regulate the electronic structure of the catalyst, keeping the binding energy of reaction intermediates within a moderate range. This avoids site passivation caused by excessive adsorption and prevents kinetic limitations caused by excessively weak adsorption. Therefore, this composite material exhibits synergistic advantages in improving conductivity, enhancing structural stability, and improving resistance to sulfur poisoning, providing a new material design approach for constructing efficient and durable SOR electrocatalytic systems. Summary of the Invention

[0006] This invention provides a method for preparing a cuprous sulfide / tungsten sulfide (Cu2S / WS2) composite electrocatalyst, which exhibits excellent catalytic activity, high stability, and corrosion resistance in electrocatalytically coupled hydrogen production processes. It can be effectively applied in SOR and HER coupled electrolysis systems. Through the application of this material, low-energy-consumption and high-efficiency hydrogen production and hydrogen sulfide decomposition can be achieved, providing an ideal solution for green energy production and pollution control.

[0007] Specifically, this invention provides a method for preparing a cuprous sulfide / tungsten sulfide composite electrocatalyst, characterized by its ability to effectively remove and recycle toxic sulfide waste and efficiently and cost-effectively produce hydrogen. The method is as follows: An electrolytic cell containing a cation exchange membrane was used, with a platinum mesh electrode as the cathode and a cuprous sulfide / tungsten sulfide composite electrocatalyst (Cu₂S / WS₂ / NF) supported on nickel foam as the anode. H₂SO₄ solution was added to the cathode reaction chamber as the cathode electrolyte, and NaOH solution containing Na₂S·9H₂O was added to the anode reaction chamber as the anode electrolyte. The anode electrolyte in the anode reaction chamber underwent a coupled electrolytic reaction under stirring at room temperature. The anode electrolyte was acidified, filtered, washed, and dried to obtain sulfur powder, while hydrogen gas was obtained from the cathode reaction chamber. The anode was prepared by the following method: (1) Pretreatment of nickel foam; (2) Prepare a solution containing L-cysteine ​​(C3H7NO2S) and sodium tungstate (Na2WO4); (3) Using a simple hydrothermal synthesis method, the solution is transferred to an autoclave, kept at a set temperature for a certain time, and the resulting material is washed and vacuum dried. (4) Prepare a solution containing copper nitrate (Cu(NO3)2) and urea (CO(NH2)2); (5) Assemble a single-chamber electrolytic cell system containing the nickel foam obtained in step (2) as the working electrode, the platinum mesh electrode as the counter electrode, the Ag|AgCl electrode as the reference electrode, and the solution obtained in step (3) as the electrolyte. (6) After connecting to the electrochemical workstation, apply a constant potential to the working electrode for a certain period of time; (7) After the sulfidation reaction, the material is washed and vacuum dried to obtain the anode.

[0008] Furthermore, using a platinum mesh electrode as the cathode, a 0.5 M H2SO4 solution was added to the cathode reaction chamber; Furthermore, in the anolyte, the concentration of Na2S·H2O is 1 M, and the concentration of NaOH is 1 M;

[0009] Furthermore, 1 mmol of C3H7NO2S and 1 mmol of Na2WO4 were added and placed in 35 mL of water. The solution was stirred for 15-35 min. Furthermore, the reaction temperature in the autoclave is 180~200℃, and the reaction time is 10~12h; Furthermore, the material was washed three times each with deionized water and anhydrous ethanol, and the vacuum drying temperature was 50~70℃. Furthermore, the concentration of Cu(NO3)2 in the solution is 0.08 mol / L, and the concentration of CO(NH2)2 is 0.08 mol / L; Furthermore, the constant potential is -0.6 V to -0.4 V, and the energizing time is 3 min to 5 min; Furthermore, the sulfidation reaction is carried out in a solution with a Na2S·9H2O concentration of 0.1 mol / L; Furthermore, the material was washed three times each with deionized water and methanol, and the vacuum drying temperature was 50~70℃. This invention proposes a method for preparing a cuprous sulfide / tungsten sulfide (Cu2S / WS2) composite electrocatalyst, which can be used for the effective removal of sulfides. The first inventive point lies in the formation of a cuprous sulfide (Cu2S) supported layer on the surface of tungsten sulfide (WS2) through a combination of hydrothermal reaction and electrodeposition. This composite material optimizes the electronic structure of the catalyst by regulating the binding energy between the active sites and reaction intermediates, significantly enhancing the activity of the catalytic sites while ensuring moderate adsorption strength of sulfur species, thus significantly improving the stability of the catalyst. The second inventive point is that, compared to simple water electrolysis for hydrogen production, the addition of Na2S facilitates the reaction and improves the efficiency of hydrogen production at the cathode. The method of this invention features mild conditions, low material cost, strong operability, and suitability for large-scale production, demonstrating excellent prospects for industrial application. Attached Figure Description

[0010] Figure 1 XRD pattern of Cu2S / WS2 / NF Figure 2 (a)-(c) Scanning electron microscope (SEM) images of Cu₂S / WS₂ / NF at different magnifications; (d) Transmission electron microscope (TEM) images; (e)-(f) Field emission transmission electron microscope (FE-TEM) images; (g)-(j) EDS elemental mapping spectra. Figure 3 XPS plot of Cu2S / WS2 / NF Figure 4 (a) OER and SOR performance of Cu2S / WS2 / NF and (b) WS2 / NF and (c) Tafel slope Figure 5(a) UV-Vis absorption spectra of Cu2S / WS2 / NF and WS2 / NF after 3600 s, within 30 min; (b) UV-Vis absorption spectra of Cu2S / WS2 / NF and WS2 / NF at different reaction times within 30 min; (c) UV-Vis absorption spectra of WS2 / NF at different reaction times within 30 min; (d) UV-Vis absorption spectra of Cu2S / WS2 / NF electrolyte at different reaction times within 8 h. Figure 6 In-situ Raman spectra of Cu2S / WS2 / NF Figure 7 Stability testing of Cu2S / WS2 / NF Example

[0011] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, embodiments and comparative examples are provided to illustrate the present invention in more detail, but the present invention is not limited to these embodiments without departing from its spirit. Example

[0012] (1) Cu2S / WS2 / NF Nickel foam was ultrasonically treated with acetone for 15 min to remove surface oil; further, it was ultrasonically treated with ethanol for 15 min to remove residual acetone; further, it was ultrasonically treated with 3 M hydrochloric acid for 15 min to remove metal oxides from the surface; further, it was ultrasonically treated with ethanol multiple times until the solution was clear and colorless; further, it was vacuum dried for 40 min; further, 1 mmol of C3H7NO2S2 and 1 mmol of Na2WO4 were placed in a beaker containing 35 mL of water and stirred until completely dissolved; further, the solution was transferred to a Teflon stainless steel autoclave and kept at 180 °C for 10 h; further, the obtained material was washed three times with deionized water and anhydrous ethanol, and dried at 60 °C; further, a solution containing copper nitrate (Cu(NO3)2) and urea (CO(NH2)2) was prepared, both at a concentration of 0.08 mol / L; further, it was cut into 1×2 A 1 cm diameter nickel foam was used as the working electrode, a platinum mesh electrode as the counter electrode, and an Ag|AgCl electrode as the reference electrode. The prepared solution was used as the electrolyte. A single-chamber electrolytic cell system was assembled, ensuring that the working electrode immersed in the electrolyte had an area of ​​1 × 1 cm. Further, after connecting to an electrochemical workstation, a constant potential of -0.5 V was applied to the working electrode for 240 s. Afterward, the material was removed and rinsed with deionized water. Further, a 0.1 mol / L Na₂S·9H₂O solution was prepared. Further, NF loaded with the precursor product was immersed in the above solution and soaked at 30 °C for 10 min. Further, the obtained material was washed three times with deionized water and methanol, and dried at 60 °C to obtain Cu₂S / WS₂ / NF.

[0013] Comparative Example 1 (2) WS2 / NF Nickel foam was ultrasonically treated with acetone for 15 min to remove surface oil. Further, it was ultrasonically treated with ethanol for 15 min to remove residual acetone. Further, it was ultrasonically treated with 3 M hydrochloric acid for 15 min to remove metal oxides from the surface. Further, it was ultrasonically treated with ethanol multiple times until the solution was clear and colorless. Further, it was vacuum dried for 40 min. Further, 1 mmol of C3H7NO2S2 and 1 mmol of Na2WO4 were placed in a beaker containing 35 mL of water and stirred until completely dissolved. Further, the solution was transferred to a Teflon stainless steel autoclave and kept at 180 °C for 10 h. Further, the obtained material was washed three times with deionized water and anhydrous ethanol, and dried at 60 °C to obtain WS2 / NF.

[0014] Experiments and Data 1. Catalyst performance testing A three-electrode H-type electrolytic cell was constructed, with the two chambers separated by an anion exchange membrane. Cu₂S / WS₂ / NF was used as the working electrode, a platinum mesh electrode as the counter electrode, and a Hg|HgO electrode as the reference electrode. The anolyte used was 1 M NaOH, and the catholyte was 0.5 M H₂SO₄. The instrument used was a Chenhua 660E electrochemical workstation, and the specific test conditions are as follows: Test method: LSV-Linear Sweep Voltammetry Scan speed: 0.005 V / s Voltage stabilization time: 2 seconds Sensitivity: 1.e -001 A / V The anode chamber was filled with 10 mL of 1M NaOH, and the cathode chamber was filled with 10 mL of 0.5 M H2SO4. During the test, the portion of the catalyst immersed in the liquid was 1 x 1 cm to minimize the impact of the resistance of each part on the actual performance of the catalyst. After testing the oxygen evolution performance of water electrolysis, 1M Na2S was added to the anode end, and the same method was used to test the sulfide oxidation (SOR) performance of the catalyst.

[0015] 2. S in SOR 2- Conversion rate test (1) Prepare a 50 mL solution of 1 M NaOH + 1 M Na2S. During the test, the size of the catalyst immersed in the liquid surface is 1 x 1 cm. After 3600 s, remove the catalyst, put the immersed part into 5 mL of deionized water and shake for 1 min, and take out 20 μL of the shaken deionized water for dilution (100 times). Use a UV-spectrum spectrophotometer to perform spectral measurements at 200-350 nm.

[0016] (2) A three-electrode H-type electrolytic cell was constructed, with the two chambers separated by a cation exchange membrane. Cu2S / WS2 / NF was used as the working electrode, a platinum mesh electrode as the counter electrode, and Hg|HgO as the reference electrode. The electrolyte used in the test was 1 M NaOH + 1 M Na2S. The instrument used was a Chenhua 660E electrochemical workstation, and the specific test conditions were as follows: Test method: it Curve Runtime: 30 min Voltage stabilization time: 2 seconds Sensitivity: 1.e -001 A / V Each chamber was filled with 10 mL of 1 M NaOH, and 2.4 g of Na₂S·9H₂O was added to the anode to achieve a concentration of 1 M. During testing, the catalyst was immersed in the liquid for a size of 1 x 1 cm. The catalyst was removed at different times (5, 10, 15, 25, 30 min), and the immersed portion was placed in 5 mL of deionized water and shaken for 1 min. 20 μL of the shaken deionized water was then used for dilution (100-fold), and the spectra were measured using a UV-Vis spectrophotometer at 200–350 nm.

[0017] 3. Study and testing of SOR reaction pathway and intermediate products (1) A three-electrode electrolytic cell was constructed, with Cu2S / WS2 / NF as the working electrode, a platinum wire electrode as the counter electrode, and an Ag|AgCl electrode as the reference electrode. The electrolyte used in the test was 1 M NaOH + 1 M Na2S. The instrument used was a Chenhua 660E electrochemical workstation, and the specific test conditions were as follows: Test method: it Curve Voltage stabilization time: 2 seconds Sensitivity: 1.e -001 A / V A solution of 1 M NaOH + 1 M Na₂S was added to the electrolytic cell to bring the catalyst surface level with the liquid level. An electrochemical workstation was connected, and in-situ Raman signals were acquired via Raman spectroscopy during the electrocatalytic reaction. Background was measured first at the open-circuit potential, followed by the application of different constant voltages (0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5 V). Raman signals were acquired at each potential for a certain duration to test the dynamic response characteristics of the catalyst's electrocatalytic signal and in-situ conductivity signal.

[0018] (2) A three-electrode H-type electrolytic cell was constructed, with the two chambers separated by a cation exchange membrane. Cu2S / WS2 / NF was used as the working electrode, a platinum mesh electrode as the counter electrode, and Hg|HgO as the reference electrode. The electrolyte used in the test was 1 M NaOH + 1 M Na2S. The instrument used was a Chenhua 660E electrochemical workstation, and the specific test conditions were as follows: Test method: it Curve Runtime: 8 hours Voltage stabilization time: 2 seconds Sensitivity: 1.e -001 A / V Each chamber was filled with 10 mL of 1 M NaOH, and 2.4 g of Na₂S·9H₂O was added to the anode to achieve a concentration of 1 M. During testing, the catalyst was immersed in the liquid to a depth of 1 x 1 cm. 20 μL of electrolyte samples were taken at different time points (0, 1, 2, 4, 6, 8 h) and immediately diluted (100-fold). Spectroscopic measurements were performed using a UV-spectrum spectrophotometer at 250–450 nm.

[0019] 4. SOR stability test A three-electrode H-type electrolytic cell was constructed, with the two chambers separated by a cation exchange membrane. Cu₂S / WS₂ / NF was used as the working electrode, a platinum mesh electrode as the counter electrode, and a Hg|HgO electrode as the reference electrode. The electrolyte used was 1M NaOH, and the instrument used was a Chenhua 660E electrochemical workstation. Specific testing conditions are as follows: Test method: it Curve Test potential: 0.2 V vs. RHE Voltage stabilization time: 2 seconds Sensitivity: 1.e -001 A / V The cathode electrolyte is 60 mL of 1 M NaOH, and the anode electrolyte is 60 mL of 1 M NaOH + 1 M Na2S. The anode electrolyte is replaced every 20 h.

[0020] Experimental results 1. Successful preparation of Cu2S / WS2 / NF materials The catalyst prepared by the method described in this embodiment was characterized by X-ray diffraction (XRD). Figure 1 The XRD pattern of the synthesized material shows diffraction peaks matching those of Cu (PDF#04-0836) and Cu₂S (PDF#26-1116). The main diffraction peaks are located at 43.3°, 50.4°, 74.1° and 26.5°, 37.4°, 45.8°, 48.5°, 54.6°, 61.4°, corresponding to the (111), (200), (220) and (002), (102), (110), (220) crystal planes of Cu and Cu₂S, respectively. The intensity and position of these peaks are consistent with the XRD pattern of Cu₂S reported in the literature, indicating that the Cu₂S phase was successfully synthesized. However, no diffraction peaks related to WS₂ were observed in the XRD pattern. This may be because the tungsten content is low, below the detection limit of XRD, thus making it impossible to detect obvious diffraction peaks. Inductively coupled plasma (ICP) analysis revealed that the W content in the material was 1.3%, confirming the above hypothesis.

[0021] like Figure 2 As shown in (a)-(c), the morphology and microstructure of the Cu2S / WS2 / NF samples were observed using scanning electron microscopy (SEM). After hydrothermal reaction and subsequent electrodeposition, a dense layer of active material was uniformly grown on the surface of the nickel foam substrate, and the three-dimensional framework structure of the nickel foam remained intact without obvious collapse or damage. This complete conductive framework not only improves the overall mechanical stability of the electrode but also provides a continuous channel for electron transport. Under magnification, it can be seen that the formed active layer is mainly composed of regularly arranged nanosheet units, which self-assemble into a cluster-like three-dimensional aggregate structure. This structure significantly increases the specific surface area and the number of exposed active sites of the material, while forming abundant pore channels inside the structure, which is conducive to the full penetration of electrolyte and the rapid transport of reactants and products, thereby effectively improving its electrocatalytic activity and overall performance. Figure 2 (d) is a projection electron microscope (TEM) image of the material, further revealing its internal structural features at the nanoscale. The image shows a layered structure composed of ultrathin nanosheets, corresponding to the clustered aggregates observed in the SEM. Different lattice fringes indicate a tight bond between the Cu₂S and WS₂ phases, facilitating interfacial charge transfer and electron transport, thus providing the structural basis for the material's high electrocatalytic activity. Figure 2 (e) and (f) are field emission transmission electron microscopy (FE-TEM) images of the material, showing two sets of lattice spacings of 0.615 and 0.200 nm, respectively, corresponding to the (002) crystal plane of WS2 and the (110) crystal plane of Cu2S. Figure 2 The EDS elemental mapping of (g)-(j) verifies the uniform distribution of Cu, S, and W elements on the catalyst surface. Figure 3 The X-ray photoelectron spectroscopy (XPS) of the material showed that after oxidation, the metal elements in the material mainly appeared in the form of high oxidation states (Cu). 2+ W 6+ ), while the S element is mainly composed of S 2- The valence state of metals increases. In electrocatalytic oxidation, high-valence metals have a strong electron affinity, allowing them to gain electrons from the electrolyte, promoting electron loss and accelerating reaction kinetics, thereby improving overall oxidation efficiency.

[0022] 2. Electrocatalytic performance of Cu2S / WS2 / NF like Figure 4 (ac) Cu2S / WS2 / NF exhibits excellent SOR performance; in a 1 M NaOH electrolyte, Cu2S / WS2 / NF requires a potential of 1.468 V vs. RHE to reach 100 mA cm⁻¹. -2The current density was [unclear], but with the addition of Na2S, the same current density was achieved at a low potential of only 0.201 V vs. RHE, reaching 300 mA cm⁻¹. -2 The industrial-grade current density required is only 0.345 V vs. RHE, indicating that the addition of Na2S significantly accelerates the reaction kinetics and improves the catalytic performance of the material. In contrast, WS2 / NF requires 1.741 V vs. 0.616 V vs. RHE for the OER and SOR reactions, respectively, demonstrating that the introduction of Cu2S optimizes the electronic structure of the catalyst and significantly enhances the activity of the catalytic sites. Furthermore, the Tafel slope of Cu2S / WS2 / NF is 38.4 mV dec. -1 This is far lower than the 94.9 mV dec of WS2 / NF. -1 This further illustrates that the SOR reaction kinetics of Cu2S / WS2 / NF is faster.

[0023] 3. Cu2S / WS2 / NF in SOR 2- Conversion rate To more comprehensively evaluate the differences in catalytic performance of different electrodes in SOR, the catalytic performance of the materials in SOR was further investigated. 2- Conversion rate. Figure 5 (a) The Cu2S / WS2 / NF electrode, WS2 / NF electrode, and original solution were subjected to S after standing in 1 M NaOH + 1 M Na2S solution for 3600 s. 2- Absorption peak intensity testing revealed that the Cu2S / WS2 / NF composite electrode exhibited the highest absorption peak intensity, indicating that the composite electrode effectively absorbs S... 2- It has a stronger adsorption and enrichment capacity. Figure 5 (bc) Further analysis of the S-values ​​after different reaction times under the same electrolysis conditions on both electrodes was conducted. 2- A comparative test was conducted on the changes in absorption peak intensity. As time increased, it indicated that S... 2- The peak intensity at 230 nm gradually decreases. By comparison, it was found that the decrease in absorption peak intensity of the WS2 / NF system is significantly smaller than that of the Cu2S / WS2 / NF system. Therefore, it can be inferred that the Cu2S / WS2 composite electrode not only affects the absorption peak intensity of S... 2- It has stronger adsorption capacity, and at the same time, it is more effective against S. 2- The conversion rate is faster, exhibiting faster reaction kinetics and higher catalytic activity in the SOR process.

[0024] 4. SOR reaction pathway and product analysis of Cu2S / WS2 / NF like Figure 6As shown, in-situ Raman spectroscopy was performed on the material at different potentials to investigate the SOR reaction pathway and products. It can be observed that S4... 2- (447 cm -1 The peak of S8 (472 cm⁻¹) appears at 0.25 V vs. RHE potential. -1 The peaks appear at 0.35 V vs. RHE, and when the potential is increased to 0.5 V vs. RHE, they appear at 151 and 218 cm⁻¹. -1 The other two peaks at that point also correspond to product S8. The above analysis clarifies the reaction pathway and intermediate product of SOR, namely S... 2- It is first oxidized into short-chain polysulfide intermediates, including S4. 2- Then, they are further oxidized to S8. To further verify and analyze the composition of the anolyte products, potentiostatic tests were performed on the material, and ultraviolet-visible spectrophotometer (UV-Vis) was used to detect the electrolyte products at different time points during the reaction. Figure 5 As shown in (d), an absorption peak appears at 300 nm. The absorption intensity of this peak gradually increases with increasing electrolysis time. Simultaneously, another absorption peak appears at 370 nm, corresponding to short-chain polysulfides, indicating S... 2- The process involves gradual oxidation to produce short-chain polysulfides S3. * and S4 * It is then further oxidized to product S8:S 2- →S * →S2 * →S3 * →S4 * →S8 (* indicates a catalytic site on the electrode surface) (Yu Z, Deng Z, Li Y, et al. Advances in electrocatalyst design and mechanism for sulfide oxidation reaction in hydrogen sulfide splitting[J]. Advanced Functional Materials, 2024, 34(39): 2403435.). The appearance of these peaks further confirms the formation of polysulfides during the SOR reaction. It is worth noting that due to the formation of polysulfides in the electrolyte, the light yellow electrolyte gradually turns into a dark yellow.

[0025] 5. Stability analysis of Cu2S / WS2 / NF To test the catalyst stability, a constant-potential electrolysis experiment was conducted at 0.2 V vs. RHE. During the experiment, the electrolyte was replaced every 20 hours to prevent the accumulation of reaction products from interfering with the catalytic behavior. Figure 7 As shown, the stability test lasted for 120 hours, during which the current response remained basically stable without significant decay, indicating that the catalyst has excellent long-term operational stability.

Claims

1. A method for preparing a cuprous sulfide / tungsten sulfide composite electrode material (Cu2S / WS2) and its application in the electrocatalytic oxidation of sulfides (SOR) reaction to combat sulfur poisoning, characterized in that, The method is as follows: An electrolytic cell containing a cation exchange membrane was used, with a platinum mesh as the cathode and cuprous sulfide / tungsten sulfide material supported on a nickel foam substrate as the anode. Sulfuric acid (H₂SO₄) solution was added to the cathode reaction chamber as the cathode electrolyte, and sodium hydroxide (NaOH) solution containing sodium sulfide nonahydrate (Na₂S·9H₂O) was added to the anode reaction chamber as the anode electrolyte. The electrolytes in the anode reaction chamber under stirred conditions and at room temperature under coupled electrolytic reactions. Sulfur was produced in the anode reaction chamber, and hydrogen was produced in the cathode reaction chamber. The anode was prepared by the following method: (1) Clean the nickel foam substrate; (2) Prepare a solution containing L-cysteine ​​(C3H7NO2S) and sodium tungstate (Na2WO4), add it to a high-pressure reactor, add the cleaned nickel foam from step (1), and keep it at the set temperature for a certain time; after the reaction is completed, wash and dry the resulting material. (3) Prepare solution A containing copper nitrate (Cu(NO3)2) and urea (CO(NH2)2); (4) Assemble a single-chamber electrolytic cell system containing the nickel foam obtained in step (2) as the working electrode, the platinum mesh electrode as the counter electrode, the Ag|AgCl electrode as the reference electrode, and the solution obtained in step (3) as the electrolyte. (5) After connecting to the electrochemical workstation, apply a constant potential to the working electrode for a certain period of time; (6) Prepare a solution B containing Na2S·9H2O, immerse the nickel foam obtained in step (5) in it, and keep it at a set temperature for a certain time; wash and dry the obtained material.

2. The method as described in claim 1, characterized in that, Using a platinum mesh electrode as the cathode, a 0.5 M H2SO4 solution was added to the cathode reaction chamber.

3. The method as described in claim 1, characterized in that, In the anolyte, the concentration of Na2S·9H2O is 1 M and the concentration of NaOH is 1 M.

4. The method as described in claim 1, characterized in that, The amount of C3H7NO2S added was 1 mmol, the amount of Na2WO4 added was 1 mmol, and it was placed in 35 mL of deionized water.

5. The method as described in claim 1, characterized in that, The reaction temperature in the autoclave is 180~200℃, and the reaction time is 10~12 hours.

6. The method as described in claim 1, characterized in that, The material was washed three times each with deionized water and anhydrous ethanol, and the vacuum drying temperature was 50~70 ℃.

7. The method as described in claim 1, characterized in that, The concentration of Cu(NO3)2 in solution A is 0.08 mol / L, and the concentration of CO(NH2)2 is 0.08 mol / L.

8. The method as described in claim 1, characterized in that, The constant potential ranges from -0.6 V to -0.4 V.

9. The method as described in claim 1, characterized in that, The electrodeposition constant potential energizing time for preparing the anode electrode is 3 min to 5 min.

10. The method as described in claim 1, characterized in that, The concentration of Na2S·9H2O in solution B is 0.1 mol / L.

11. The method as described in claim 1, characterized in that, The material was washed three times with deionized water and three times with methanol, and the vacuum drying temperature was 50~70 ℃.

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