Preparation method of tungsten-doped nickel-cobalt sulfide electrode material and application of tungsten-doped nickel-cobalt sulfide electrode material in anti-sulfur poisoning electro-catalytic sulfur oxidation (SOR) reaction
Through the preparation of the tungsten-doped nickel-cobalt bimetallic sulfide catalyst, the problem of insufficient conductivity and durability of transition metal sulfide in sulfur ion oxidation reaction is solved, and low-energy consumption and efficient hydrogen sulfide resource utilization and hydrogen production process is achieved, which is suitable for industrial pollution control and resource recovery.
Patent Information
- Application Number
- CN202510553616.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-29
- Publication Date
- 2025-08-22
AI Technical Summary
The existing transition metal sulfide catalysts have poor conductivity and long-term durability in sulfur ion oxidation reactions, resulting in limited industrial applications. The traditional methods of treating hydrogen sulfide have problems such as high energy consumption, serious catalyst deactivation, and difficulty in recycling by-products.
The catalyst is prepared by hydrothermal synthesis method under room temperature and normal pressure by tungsten-doped nickel-cobalt bimetallic sulfide (W-CoNi2S4) through hydrothermal synthesis method to regulate the electronic structure of the catalyst, optimize the binding energy of the active site and the reaction intermediate, and improve the durability and anti-poisoning ability of the catalyst.
It achieves efficient hydrogen production and hydrogen sulfide decomposition, and the catalyst exhibits excellent stability and corrosion resistance at low energy consumption. It is suitable for use in SOR-HER coupled electrolytic systems, improving catalytic activity and anti-sulfur poisoning ability.
Smart Images
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Abstract
Description
[0001] The present invention belongs to the technical field of electrocatalysis, and specifically discloses a preparation method and application of a tungsten-doped nickel-cobalt bimetallic sulfide bifunctional electrocatalyst. Background Art
[0002] Hydrogen sulfide (H2S) is a common industrial byproduct, widely present in oil refining, natural gas extraction, biomass degradation, and wastewater treatment processes. It is extremely toxic and corrosive. Traditional treatment methods such as the Claus process and wet oxidation face problems such as high energy consumption, severe catalyst deactivation, and difficulty in recovering byproducts. In contrast, the sulfide ion oxidation reaction, as an electrochemical recovery solution, has the advantages of high efficiency, low cost, and ease of operation. From a thermodynamic point of view, the sulfate ion oxidation reaction (SOR, E = -0.48V vs. SHE) has a lower potential than the oxygen evolution reaction (OER, 1.23V vs. RHE). In addition, the elemental sulfur generated by the anodic reaction is a key raw material in the fertilizer and rubber industries. Therefore, combining SOR with HER can not only remove sulfur-containing waste gas, but also realize the resource utilization of hydrogen sulfide, which will help to control industrial pollution and support green and low-carbon development.
[0003] Among various electrocatalytic materials, transition metal sulfides (TMSs) have unique physicochemical properties that make them the most commonly used catalyst in SOR to date. Compared to elemental oxygen, sulfur has a relatively negative electronegativity, which favors the covalent interaction between sulfur ions and unsaturated transition metal sites, resulting in a downward shift in the d-band center and optimal sulfide adsorption energy on the electrocatalyst surface. Furthermore, metal sulfides generally exhibit improved conductivity and a favorable affinity for sulfide electrolytes, both of which are beneficial as SOR catalysts. However, the poor conductivity and long-term durability of transition metal sulfides have hindered their widespread application. To address these issues, the present invention designs heteroatom-doped multinary transition metal sulfides, modulates the electronic structure of the catalyst, optimizes the binding energy between the active site and the reaction intermediate, ensures that the adsorption interaction is neither too strong nor too weak, and improves the durability and poisoning resistance of the catalyst. In summary, the combination of these two factors has developed a tungsten-doped nickel-cobalt bimetallic sulfide with a stable structure, strong conductivity, and resistance to sulfur poisoning, which has important research significance and practical application value. Summary of the Invention
[0004] The present invention provides a preparation method of tungsten-doped nickel-cobalt bimetallic sulfide (W-CoNi2S4), which realizes efficient hydrogen production and anode sulfide oxidation reaction in the electrocatalytic coupled hydrogen production process. The material has high catalytic activity, excellent stability and corrosion resistance, and can be used in the SOR-HER coupled electrolysis system to achieve low energy consumption, efficient hydrogen production and hydrogen sulfide decomposition.
[0005] Specific
[0006] The present invention provides a method for preparing tungsten-doped nickel-cobalt bimetallic sulfide, which is characterized by being able to effectively remove and recycle toxic sulfide waste and effectively produce hydrogen at low cost. The method is as follows:
[0007] An electrolytic cell containing a cation exchange membrane is used, with a platinum mesh electrode as the cathode and W-CoNi2S4 as the anode. A sodium hydroxide (NaOH) solution is added to the cathode reaction chamber as the cathode electrolyte, and a NaOH solution containing sodium sulfide (Na2S·9H2O) is added to the anode reaction chamber as the anolyte. The anolyte in the anode reaction chamber undergoes a coupled electrolysis reaction under stirring at room temperature. The anolyte is acidified, filtered, separated, washed, and dried to obtain sulfur powder, and the product obtained in the cathode reaction chamber is hydrogen. The anode is prepared by the following method:
[0008] (1) Cleaning nickel foam;
[0009] (2) preparing a solution containing urea (Co(NO3)2), cobalt nitrate (Co(NO3)2), nickel nitrate (Ni(NO3)2), and sodium tungstate (Na2WO4);
[0010] (3) Using a simple hydrothermal synthesis method, the solution is transferred to an autoclave, maintained at a set temperature for a certain period of time, and the obtained material is washed and vacuum dried;
[0011] (4) After the secondary hydrothermal sulfidation reaction, the material is washed and vacuum-dried to obtain the anode.
[0012] Furthermore, 4 mmol of Co(NO3)2, 1 mmol of Ni(NO3)2, 0.125 mmol of Na2WO4, and 5 mmol of CO(NH2)2 were added to 35 ml of water, and the solution was stirred for 25 to 35 minutes;
[0013] Furthermore, the reaction temperature of the autoclave is 150-170°C, and the reaction time is 7-9h;
[0014] Furthermore, the material was washed with deionized water and anhydrous ethanol three times each, and the vacuum drying temperature was 50-70°C;
[0015] Furthermore, 8 mmol of Na2S·9H2O was added to 40 ml of water, and the solution was stirred for 25 to 35 minutes;
[0016] Furthermore, the reaction temperature of the autoclave is 110-130°C, and the reaction time is 3-5h;
[0017] Furthermore, the material was washed with deionized water and anhydrous ethanol three times each, and the vacuum drying temperature was 50-70°C;
[0018] The present invention proposes a preparation method of tungsten-doped nickel-cobalt bimetallic sulfide, which can be used to effectively remove sulfides. The first inventive point is to regulate the electronic structure of the SOR catalyst by adding a trace amount of metal W doping and transition bimetallic sulfide, optimize the binding energy between the active site and the reaction intermediate, ensure that the adsorption effect is neither too strong nor too weak, and improve the durability and anti-poisoning ability of the catalyst. The second inventive point is that the addition of sodium sulfide is conducive to the reaction and improves the efficiency of hydrogen production. The method of the present invention can be carried out at room temperature and normal pressure, with mild conditions, low material cost, strong operability of the synthesis process and suitable for large-scale production, showing excellent industrial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 XRD pattern of W-CoNi2S4 / NF
[0020] Figure 2 SEM image of W-CoNi2S4 / NF
[0021] Figure 3 XPS pattern of W-CoNi2S4 / NF
[0022] Figure 4 SOR and OER performance of W-CoNi2S4 / NF (90% iR compensation)
[0023] Figure 5 UV-VIS spectra of W-CoNi2S4 / NF at different times
[0024] Figure 6 Stability test of W-CoNi2S4 / NF Example
[0025] In order to make the above-mentioned objects, features and advantages of the present invention more clearly understood, the present invention is described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to these Examples within the scope of the present invention.
[0026] Example 1
[0027] (1)W-CoNi2S4 / NF
[0028] The nickel foam was ultrasonically treated with acetone for 15 minutes to remove the surface oil; further, the material was ultrasonically treated with ethanol for 15 minutes to remove the residual acetone on the surface of the material; further, the material was ultrasonically treated with 3M hydrochloric acid for 15 minutes to remove the metal oxide on the surface of the material; further, the material was ultrasonically treated with ethanol for multiple times until the solution was clear and colorless; further, vacuum dried for 40 minutes; further, 4mmol of Co(NO3)2, 1mmol of Ni(NO3)2, 0.125mmol of Na2WO4 and 5mmol of CO(NH2)2 were placed in a beaker containing 35ml of water and stirred for 30min to completely dissolve; further, the solution was transferred to a Teflon stainless steel autoclave and maintained at 150°C for 8h; further, the obtained material was washed three times with deionized water and anhydrous ethanol respectively, and dried at 60°C; further, 1.93g Na2S·9H2O was placed in a beaker containing 40mL of water and stirred for 30 minutes to form a mixed solution. The solution was then transferred to a Teflon stainless steel autoclave, and the NF loaded with the precursor product was immersed in the solution and reacted at 120°C for 4 hours. The resulting material was then washed three times with deionized water and anhydrous ethanol, respectively, and dried at 60°C to obtain W-CoNi2S4.
[0029] Comparative Example 1
[0030] (2) CoNi2S4 / NF
[0031] The nickel foam was ultrasonically treated with acetone for 15 minutes to remove the surface oil; further, the material was ultrasonically treated with ethanol for 15 minutes to remove the residual acetone on the surface of the material; further, the material was ultrasonically treated with 3M hydrochloric acid for 15 minutes to remove the metal oxide on the surface of the material; further, the material was ultrasonically treated with ethanol for multiple times until the solution was clear and colorless; further, vacuum dried for 40 minutes; further, 4mmol of Co(NO3)2, 1mmol of Ni(NO3)2 and 5mmol of CO(NH2)2 were placed in a beaker containing 35ml of water and stirred for 30min to completely dissolve; further, the solution was transferred to a Teflon stainless steel autoclave and maintained at 150°C for 8h; further, the obtained material was washed three times with deionized water and anhydrous ethanol respectively, and dried at 60°C; further, 1.93g Na2S·9H2O was placed in a beaker containing 40mL of water and stirred for 30 minutes to form a mixed solution. The solution was then transferred to a Teflon stainless steel autoclave, and the NF loaded with the precursor product was immersed in the solution and reacted at 120°C for 4 hours. The resulting material was then washed three times with deionized water and anhydrous ethanol, respectively, and dried at 60°C to obtain W-CoNi2S4.
[0032] Comparative Example 2
[0033] (3)W-CoNi / NF
[0034] The nickel foam was ultrasonically treated with acetone for 15 minutes to remove surface oil; further, the material was ultrasonically treated with ethanol for 15 minutes to remove residual acetone on the surface of the material; further, the material was ultrasonically treated with 3M hydrochloric acid for 15 minutes to remove metal oxides on the surface of the material; further, the material was ultrasonically treated with ethanol multiple times until the solution was clear and colorless; further, vacuum dried for 40 minutes; further, 4mmol of Co(NO3)2, 1mmol of Ni(NO3)2, 0.125mmol of Na2WO4 and 5mmol of CO(NH2)2 were placed in a beaker containing 35ml of water and stirred for 30 minutes until they were completely dissolved; further, the solution was transferred to a Teflon stainless steel autoclave and maintained at 150°C for 8h; further, the obtained material was washed three times with deionized water and anhydrous ethanol, respectively, and dried at 60°C to obtain W-CoNi / NF.
[0035] Comparative Example 3
[0036] (4) Co-Ni / NF
[0037] The nickel foam was ultrasonically treated with acetone for 15 minutes to remove surface oil; further, the material was ultrasonically treated with ethanol for 15 minutes to remove residual acetone on the surface of the material; further, the material was ultrasonically treated with 3M hydrochloric acid for 15 minutes to remove metal oxides on the surface of the material; further, the material was ultrasonically treated with ethanol multiple times until the solution was clear and colorless; further, vacuum dried for 40 minutes; further, 4mmol of Co(NO3)2, 1mmol of Ni(NO3)2 and 5mmol of CO(NH2)2 were placed in a beaker containing 35ml of water and stirred for 30 minutes until they were completely dissolved; further, the solution was transferred to a Teflon stainless steel autoclave and maintained at 150°C for 8h; further, the obtained material was washed three times with deionized water and anhydrous ethanol, respectively, and dried at 60°C to obtain CoNi / NF.
[0038] Experiments and data
[0039] 1. Catalyst performance test
[0040] A three-electrode H-type electrolytic cell was constructed, with the two chambers separated by an anion exchange membrane. W-CoNi2S4 / 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 in the test was 1M NaOH, and the instrument used was a Chenhua 660E electrochemical workstation. The specific test conditions are as follows:
[0041] Test method: LSV-Linear Sweep Voltammetry
[0042] Scan speed: 0.005V / s
[0043] Voltage stabilization time: 2s
[0044] Sensitivity: 1.e -001 A / V
[0045] Each chamber was filled with 10 mL of 1M NaOH. During testing, the catalyst was immersed in a 1x1 cm area to minimize the impact of the electrical resistance of each component on the catalyst's actual performance. After testing the oxygen evolution performance of water electrolysis, 1M sodium sulfide was added to the anode terminal and the catalyst was tested using the same method to determine its sulfide oxidation (SOR) performance.
[0046] 2.SOR product testing
[0047] A three-electrode H-type electrolytic cell was constructed, with the two chambers separated by a cation exchange membrane. W-CoNi2S4 / 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 was 1M NaOH+1M Na2S, and the instrument used was a Chenhua 660E electrochemical workstation. The specific test conditions are as follows: Test method: it Curve
[0048] Run time: 8 hours
[0049] Voltage stabilization time: 2s
[0050] Sensitivity: 1.e -001 A / V
[0051] Each chamber was filled with 10 ml of 1M NaOH. Additionally, 2.4 g of Na₂S·9H₂O was added to the anode end to achieve a 1M concentration. During testing, the catalyst was immersed in the solution at a size of 1 x 1 cm. At various times (0, 0.5, 1, 2, 4, 6, and 8 h), 20 μl of electrolyte sample was taken and immediately diluted 100-fold. Spectra were measured at 250-450 nm using a UV spectrophotometer.
[0052] 3.SOR stability test
[0053] A three-electrode H-type electrolytic cell was constructed, with the two chambers separated by a cation exchange membrane. W-CoNi2S4 / 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 in the test was 1M NaOH, and the instrument used was a Chenhua 660E electrochemical workstation. The specific test conditions are as follows:
[0054] Test method: it Curve
[0055] Test potential: 0.4V vs. RHE
[0056] Run time: 12h
[0057] Voltage stabilization time: 2s
[0058] Sensitivity: 1.e -001 A / V
[0059] The cathode electrolyte was 60 mL 1 M NaOH, the anode electrolyte was 60 mL 1 M NaOH + 1 M Na2S, and the anode electrolyte was replaced every 12 h.
[0060] Experimental results
[0061] 1. Successful preparation of W-CoNi2S4 / NF material
[0062] The catalyst prepared by the above method of this example was characterized by X-ray diffraction (XRD). Figure 1 The XRD spectrum of the material shows no obvious characteristic diffraction peaks in the XRD spectrum of the unsulfurized precursor, indicating that the material is mainly an amorphous or low-crystallinity intermediate precursor. After sulfurization treatment, the sample XRD spectrum clearly shows diffraction peaks that match the CoNi2S4 spinel structure (PDF#04-003-9612). The main diffraction peaks are located at 31.5°, 38.0°, 50.5°, and 55.5°, corresponding to the (311), (400), (511), and (440) crystal planes of the spinel structure, respectively. The intensity and position of these peaks are consistent with the XRD spectrum of CoNi2S4 reported in the literature, confirming that the sulfurization treatment successfully induced the formation of the CoNi2S4 crystal phase, with a stable structure and good crystallinity. However, no diffraction peaks related to tungsten were observed in the XRD spectrum. This may be because the tungsten content is low, below the detection limit of XRD, so no obvious diffraction peaks can be detected.
[0063] like Figure 2 As shown, the morphology and microstructure of the samples were observed by scanning electron microscopy (SEM). Figure 2 (a) shows an SEM image of the synthesized precursor (unsulfurized). The precursor is uniformly deposited on the surface of the nickel foam substrate (NF), exhibiting a rough nanoparticle and nanospine structure, presumably a polymetallic hydroxide or hydroxytungstate precursor. The overall structure is loose but continuous, providing abundant active sites for subsequent conversion processes. Figure 2(b) is a SEM image of the post-sulfurization process. After hydrothermal sulfurization, the nickel foam substrate is evenly coated with a layer of material, while the nickel foam skeleton remains intact, contributing to the material's mechanical strength. Upon magnification, it is clearly visible that the material is primarily composed of flower-like aggregates of nanorod arrays. This unique structure significantly increases the material's specific surface area and exposed reactive sites, thereby effectively enhancing its electrocatalytic activity. Figure 3 The XPS characteristic peaks show that all elements in the catalyst are in an oxidized state. Ni and Co both have two oxidation valence states, namely, Ni has +2 and +3 valence states, Co has +2 and +3 valence states, and W presents a +6 valence state.
[0064] 2. Electrocatalytic performance of W-CoNi2S4 / NF
[0065] like Figure 4 (ac), W-CoNi2S4 shows excellent SOR performance. W-CoNi2S4 only requires a low potential of 0.297 V vs. RHE to achieve 300 mA cm -2 The current density of W-CoNi2S4 is 34.22 mV dec, which is much lower than that of CoNi / S, W-CoNi and CoNi (0.5431, 1.302 and 1.347 V vs. RHE). -1 , much lower than CoNi / S, W-CoNi and CoNi (53.81, 104.48 and 117.8mV dec -1 ), indicating that the SOR reaction kinetics of the catalyst is faster. Compared with OER, W-CoNi2S4 reaches a current density of 200mA cm -2 The potential of OER was significantly reduced by 0.85 and 1.014 V. The addition of sodium sulfide greatly improved the catalytic performance and had more thermodynamic advantages than OER.
[0066] 3. Analysis of SOR products of W-CoNi2S4 / NF
[0067] In order to analyze the composition of the anode product, a constant current test was carried out at a current density of 100 mA cm-2, and the products in the electrolyte were detected during the reaction. The electrolyte at different reaction time points was analyzed using an ultraviolet-visible spectrophotometer (UV-Vis). As shown in the figure, an absorption peak appeared at 300 nm. As the electrolysis time increased, the maximum absorption intensity of the absorption peak increased. At the same time, an additional absorption peak appeared at 370 nm, corresponding to short-chain polysulfides (S2 2- –S4 2- ). The appearance of these peaks proves the generation of polysulfides in the electrolyte. It is worth noting that the light yellow electrolyte gradually turns into dark yellow due to the generation of polysulfides in the electrolyte.
[0068] The polysulfide solution was collected and acidified by adding concentrated sulfuric acid until the pH reached 1. The polysulfide solution was kept in an ice bath for several hours to reduce the exothermic reaction. A yellow solid was obtained by filtration, washing, and drying, which was confirmed to be elemental sulfur by XRD analysis.
[0069] 4. Stability analysis of W-CoNi2S4 / NF
[0070] In order to analyze the stability of the material, a constant potential test was carried out at a potential of 0.5 V vs. RHE, and the electrolyte was replaced every 12 hours during the test to prevent the accumulation of products from affecting the electrode performance. Figure 6 The stability test lasted for 206 hours, during which the electrode performance remained good, showing excellent long-term stability.
Claims
1. A method for preparing a tungsten-doped nickel-cobalt sulfide electrode material (W-NiCo2S4) and its application in sulfur-poisoning-resistant electrocatalytic sulfur oxidation (SOR) reaction, characterized in that: The method is as follows: An electrolytic cell containing a cation exchange membrane is used, with a platinum mesh as the cathode and a tungsten-doped nickel-cobalt bimetallic sulfide material supported on a nickel foam substrate as the anode. A sodium hydroxide solution is added to the cathode reaction chamber as the cathode electrolyte, and a sodium hydroxide solution containing sodium sulfide nonahydrate is added to the anode reaction chamber as the anode electrolyte. The electrolytes in the anode reaction chamber undergo a coupled electrolysis reaction under stirring and room temperature conditions, wherein the anode reaction chamber produces sulfur as a product and the cathode reaction chamber produces hydrogen as a product. The anode is prepared by the following method: (1) Cleaning the nickel foam substrate; (2) preparing a solution containing urea (Co(NO3)2), cobalt nitrate (Co(NO3)2), nickel nitrate (Ni(NO3)2), and sodium tungstate (Na2WO4), adding the solution to a high-pressure reactor, adding the cleaned nickel foam treated in step (1), and maintaining the solution for a certain period of time under a set stability; after the reaction is completed, washing and drying the obtained material; (3) preparing a solution containing sodium sulfide nonahydrate, adding the solution to a high-pressure reactor, adding the nickel foam obtained in step (2), and maintaining the solution under a set stability for a certain period of time; and washing and drying the obtained material.
2. The method according to claim 1, wherein The amount of Co(NO3)2 added was 4 mmol, the amount of Ni(NO3)2 was 1 mmol, the amount of Na2WO4 was 0.125 mmol, and the amount of CO(NH2)2 was 5 mmol, and they were placed in 35 ml of water.
3. The method according to claim 1, wherein The stirring time of the solution is 25 to 35 minutes.
4. The method according to claim 1, wherein The reaction temperature of the autoclave is 150-170° C., and the reaction time is 7-9 hours.
5. The method according to claim 1, wherein Deionized water and anhydrous ethanol were used three times each for washing the material, and the vacuum drying temperature was 50-70°C.
6. The method according to claim 1, wherein The amount of Na2S·9H2O added was 8 mmol, which was placed in 40 ml of water.
7. The method according to claim 1, wherein The solution stirring time is 25 to 35 minutes.
8. The method according to claim 1, wherein The reaction temperature of the autoclave is 110-130° C., and the reaction time is 3-5 hours.
9. The method according to claim 1, wherein Deionized water and anhydrous ethanol were used three times each for washing the material, and the vacuum drying temperature was 50-70°C.