A self-supported cobalt-nickel bimetallic sulfide heterostructure anode electrocatalyst, a preparation method and application thereof

Abstract

The application discloses a kind of foam nickel self-supporting cobalt nickel double-metal sulfide heterostructure electrocatalyst and its preparation method and application on anode.It is prepared by two-step simple solvothermal method with foam nickel as substrate: first, vertical growth two-dimensional Co-MOF nanosheet array in situ on pretreated foam nickel;With this as precursor, further solvothermal synthesis of cobalt nickel double-metal sulfide heterostructure with cloud layer sheet shape and mutual connection is added to sulfur source.The application is wrapped by two-dimensional Co-MOF nanosheet to foam nickel, which improves the sulfidation corrosion of foam nickel and improves the crystallinity of in-situ grown material.The prepared cobalt nickel double-metal sulfide heterostructure material has smooth pore and high-density active site, and can be used as anode electrocatalyst for efficient electrooxidation of lignin model compound.The electrocatalyst is cheap, efficient and stable, easy to realize scale, and can be popularized to other biomass-derived platform compound conversion and utilization.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of biomass-derived compound conversion and electrocatalytic material manufacturing, and particularly relates to a foam nickel self-supported Co3S4 / NiS heterojunction anode electrocatalyst, a preparation method and application thereof. BACKGROUND

[0002] In order to get rid of the dependence on fossil energy and reduce environmental pollution, people are promoting the use of renewable resources, especially biomass. Lignin, as one of the main components of lignocellulose, is the most abundant renewable polymer containing aromatic structure, which makes it an attractive platform chemical production raw material. However, due to the complexity and intractability of lignin structure, its current use is mostly focused on direct combustion to release heat value. Therefore, the high-value utilization of lignin is meaningful and challenging, and the typical beta-O-4 type lignin model compound, 2-phenoxy-1-phenylethanol (PPE), has become one of the breakthroughs for the high-value utilization of lignin.

[0003] The oxygen evolution reaction (OER) has a slow kinetics, which is a key factor limiting the overall energy conversion efficiency of water electrolysis. The anodic electrooxidation of biomass-derived platform compounds has more excellent kinetics and thermodynamic performance, which becomes an effective strategy to replace OER, and also provides an effective method for PPE electrooxidation and upgrading. However, there are few studies on the corresponding catalysts at home and abroad at present, so it is an urgent need and challenge to reasonably select and design anode electrocatalysts.

[0004] In recent years, cobalt-based and nickel-based sulfides, as substitutes for noble metals, can be used as high-quality anode oxidation electrocatalysts based on their high activity, unique electronic structure, abundance and low cost. By reasonably designing the interface structure of cobalt-nickel bimetallic sulfide catalysts, the catalytic performance can be effectively improved.

[0005] However, cobalt-nickel bimetallic sulfide electrocatalysts have not been studied in the field of oxidation of lignin and model compounds. In addition, direct in-situ synthesis of heterostructures on high-conductivity foam nickel can further free the electrode material from the burden of adhesives. However, unprotected direct sulfidation method can accelerate the corrosion of foam nickel, reduce the stability and conductivity of the catalytic material. Therefore, it is a great challenge to develop an electrooxidation catalyst with simple, efficient, stable and low production process. SUMMARY

[0006] Therefore, the present application provides a foam nickel self-supported cobalt-nickel bimetallic sulfide heterostructure anode electrocatalyst to realize efficient 2-phenoxy-1-phenylethanol electrooxidation (POR).

[0007] The purpose of the present application can be achieved by the following technical solutions: taking foamed nickel as a self-supporting substrate, first wrapping a two-dimensional Co-MOF nanosheet array vertically grown on the surface of the foamed nickel as a sacrificial template, and then realizing the formation of a sheet-shaped stacked Co3S4 and a Co3S4-(α,β)-NiS heterojunction on the surface of the foamed nickel through a simple sulfidation process. The wrapping of the Co-MOF on the foamed nickel plays a role in weakening the sulfidation corrosion. In addition, the performance of the electrocatalytic conversion of PPE is effectively improved by obtaining a heterogeneous catalytic species and exposing a high-density active site. The preparation process is simple and controllable, and the crystallinity is good.

[0008] Name explanation:

[0009] NF: foamed nickel. Co-MOF: cobalt-based metal organic framework. PVP: polyvinylpyrrolidone. NF@Co-MOF NP: cobalt-based metal organic framework nanosheet array grown on foamed nickel. PPE: 2-phenoxy-1-phenylethanol. POR: 2-phenoxy-1-phenylethanol oxidation reaction. HER: hydrogen evolution reaction. RHE: reversible hydrogen electrode.

[0010] A foamed nickel self-supporting cobalt-nickel double metal sulfide heterostructure anode electrocatalyst, characterized in that foamed nickel wrapped with a Co-MOF nanosheet array is used as a sacrificial template, and a cloud-shaped sheet-shaped stacked block structure is formed by connecting the vertically grown nanosheets to each other through a sulfidation process, and a cobalt-nickel double metal sulfide heterostructure is formed on the surface of the foamed nickel.

[0011] Preferably, in the XRD spectrum of NF@Co3S4 / (α,β)-NiS-180-5, 31.48° and 55.14° correspond to the (311) and (440) characteristic faces of Co3S4, 30.02°, 34.5° and 45.62° correspond to the (100), (101) and (102) characteristic faces of α-NiS, respectively; Co3S4, α-NiS and β-NiS coexist.

[0012] Further, the preparation method of the foamed nickel self-supporting cobalt-nickel double metal sulfide heterostructure anode electrocatalyst specifically includes the following steps:

[0013] (1) Foamed nickel (NF, 5 cm x 1 cm x 0.1 cm) is washed with acetone, 1-3 mol / L HCl solution and deionized water in sequence, and vacuum dried. -1 hydrochloric acid solution and deionized water, and vacuum dried.

[0014] (2) Take the cobalt nitrate hexahydrate and 1,3,5-benzenetricarboxylic acid and dissolve them in a mixed solution of N,N-dimethylformamide and ethanol to obtain solution A. Preferably, the molar ratio of cobalt nitrate hexahydrate to 1,3,5-benzenetricarboxylic acid is 2-4:1; more preferably, the molar ratio of cobalt nitrate hexahydrate to 1,3,5-benzenetricarboxylic acid is 3:1. In the mixed solution of N,N-dimethylformamide and ethanol, the volume ratio of N,N-dimethylformamide to ethanol is 0.5-2:1, and most preferably 1:1.

[0015] The ratio of cobalt nitrate hexahydrate to 1,3,5-benzenetricarboxylic acid to the mixed solution is 2-4 mol:0.5-1.5 mol:20 L. Preferably, the ratio of cobalt nitrate hexahydrate to 1,3,5-benzenetricarboxylic acid to the mixed solution is 3 mol:1 mol:20 L.

[0016] Then polyvinylpyrrolidone (PVP) is dissolved in deionized water to obtain solution B, and the concentration of PVP is 0.04-0.06 g / ml -1 . Preferably, the concentration of PVP is 0.05 g / ml -1 .

[0017] Solution A and solution B are stirred and mixed. A mixed solution is obtained. The ratio of solution A to solution B is 0.5-2:1, and preferably the ratio of solution A to solution B is 1:1.

[0018] (3) Take a certain amount of mixed solution and transfer it to a stainless steel Teflon-lined autoclave containing a vertically placed NF, set the constant temperature air drying oven at 170-190°C and heat for 8-12 h, then rinse with ethanol and deionized water in turn, and vacuum dry. Grow the cobalt-based metal organic framework nanosheet array (NF@Co-MOF NP) precursor on the foam nickel. Preferably, set the constant temperature air drying oven at 180°C and heat for 10 h, and vacuum dry at 60°C for 6 hours.

[0019] (4) Under ultrasonic conditions, take the organic sulfur-containing compound and dissolve it in anhydrous ethanol, then transfer it to a reaction kettle containing a vertically placed NF@Co-MOF NP, and set the constant temperature air drying oven at 180-240°C and heat for 3-7 h, then rinse with ethanol and deionized water in turn, and vacuum dry, finally obtaining the foam nickel self-supported Co3S4 and (α,β)-NiS heterostructure electrocatalyst (NF@Co3S4 / (α,β)-NiS).

[0020] Preferably, the autoclave is placed in a constant temperature air drying oven for heating; the constant temperature drying oven is used to heat the autoclave; and both the rinsing and vacuum drying are performed on the prepared material, i.e., the catalyst grown on the foam nickel.

[0021] Further, the foam nickel in step (1) is sequentially cleaned with acetone, 1-3 mol / L HCl solution and deionized water as cleaning agents, and the cleaning time of each cleaning agent is 10-30 min. -1 The foam nickel is cleaned with acetone, 1-3 mol / L HCl solution and deionized water as cleaning agents, and the cleaning time of each cleaning agent is 10-30 min.

[0022] Further, the organic sulfur-containing compound in step (4) is one of thiourea and thioacetamide, and the concentration of the organic sulfur-containing compound is 3-6 mmol / L. -1 The organic sulfur-containing compound is used as a sulfur source, and hydrogen sulfide is released by decomposition of the organic sulfur-containing compound at high temperature to participate in the reaction.

[0023] Further, the organic sulfur-containing compound in step (4) is dissolved in anhydrous ethanol, and the volume of the anhydrous ethanol is 20-30 mL.

[0024] Further, the temperature of the constant-temperature air-drying oven in step (4) is set to 180-240 DEG C, and the reaction time is 3-7 h.

[0025] A foam nickel self-supporting cobalt-nickel bimetallic sulfide heterostructure anode electrocatalyst is prepared by the above preparation method.

[0026] The foam nickel self-supporting cobalt-nickel bimetallic sulfide heterostructure anode electrocatalyst is used for electrooxidation conversion of a lignin model compound in an alkaline solution.

[0027] Further, the alkaline solution is one or both of a sodium hydroxide solution and a potassium hydroxide solution, and the concentration is 1 mol / L. -1 The two alkaline solutions have good conductivity and the electrode is not easy to be polarized.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] 1. The foam nickel self-supporting cobalt-nickel double metal sulfide heterostructure anode electrocatalyst in the application is prepared by taking foam nickel as the base and through a two-step simple solvothermal method, the prepared cobalt-nickel double metal sulfide heterostructure material has smooth pores and high-density active sites, and can be used as an anode electrocatalyst for efficient electrooxidation of lignin model compounds. The preparation process is simple, the electrocatalyst is stable, the energy consumption is low, and large-scale production is facilitated. It can be popularized in the conversion and utilization of other biomass-derived platform compounds.

[0030] 2. The foam nickel with high porosity and good conductivity is selected as the self-supporting base in the application, and the double metal sulfide is grown in situ, so that the electrochemical performance of the catalyst can be enhanced, and the use of the binder is avoided, thereby further reducing the production cost of the electrode.

[0031] 3. The foam nickel is wrapped with two-dimensional Co-MOF nanosheet arrays before sulfuration in the application, which not only improves the contact area of the catalytic material and the reaction molecules, but also effectively adjusts the stability of the catalyst and promotes the formation of the heterostructure. The sulfuration corrosion of the foam nickel is improved, and the crystallinity of the in-situ grown material is improved.

[0032] 4. The foam nickel self-supporting cobalt-nickel double metal sulfide heterostructure electrocatalyst is used to electrooxidize lignin model compounds (PPE) in the application. In a 1 mol L base solution containing 1 mmol L of PPE, only 1.107 V vs RHE is required to reach a characteristic current density of 10 mA cm -1 . -1 -2 RHE is a reversible hydrogen electrode, and V vs RHE is a voltage unit, which means the voltage relative to the reversible hydrogen electrode. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 Figure 6 is an XRD spectrum of the NF@Co3S4 / (α,β)-NiS-180-5 catalyst obtained in Example 1;

[0034] Figure 2 Figure 7 is a SEM image of the NF@Co-MOF NP precursor prepared in Example 1;

[0035] Figure 3 Figure 8 is a SEM image of the NF@Co3S4 / (α,β)-NiS-180-5 catalyst prepared in Example 1;

[0036] Figure 4 Figure 9 is an EDS element distribution map of the NF@Co3S4 / (α,β)-NiS-180-5 catalyst prepared in Example 1;

[0037] Figure 5 ​XPS spectra of the NF@Co3S4 / (a, b)-NiS-180-5 catalyst obtained in Example 1;

[0038] Figure 6 Linear sweep plots of the NF@Co3S4 / (a, b)-NiS-180-5 catalyst prepared in Example 1 in alkaline solution with and without PPE;

[0039] Figure 7 Impedance plots of the NF@Co3S4 / (a, b)-NiS-180-5 catalyst prepared in Example 1;

[0040] Figure 8 Current density difference versus scan rate linear fitting plots of the NF@Co3S4 / (a, b)-NiS-180-5 catalyst prepared in Example 1;

[0041] Figure 9 Conversion and yield plots of PPE electrocatalytically oxidized by the NF@Co3S4 / (a, b)-NiS-180-5 catalyst prepared in Example 1 and other catalysts for 7h;

[0042] Figure 10 Conversion and yield plots of PPE electrocatalytically oxidized by the NF@Co3S4 / (a, b)-NiS-180-5 catalyst prepared in Example 1 for 3 times continuously;

[0043] Figure 11 LSV curves of the NF@Co3S4 / (a, b)-NiS-180-5 catalyst prepared in Example 1 scanned in a coupled POR and HER electrolytic cell;

[0044] Figure 12 Gas production of anode and cathode of the NF@Co3S4 / (a, b)-NiS-180-5 catalyst prepared in Example 1 in a coupled POR and HER electrolytic cell. DETAILED DESCRIPTION

[0045] The application will be described in detail below with reference to the drawings and specific embodiments. The following examples are implemented on the premise of the technical solution of the application, and detailed implementation modes and specific operation processes are given, but the protection scope of the application is not limited to the following examples.

[0046] Example 1

[0047] (1) A piece of nickel foam was cut and sequentially washed with acetone, 1 mol / L HCl solution and deionized water for 10 min each time under ultrasonic, and vacuum dried. -1

[0048] ​(2) Take 3 mmol of cobalt nitrate hexahydrate and 1 mmol of 1,3,5-benzenetricarboxylic acid and dissolve them in a mixed solution of N,N-dimethylformamide and ethanol (solution A). In the mixed solution of N,N-dimethylformamide and ethanol, the volume ratio of N,N-dimethylformamide to ethanol is 1:1; the ratio of cobalt nitrate hexahydrate to 1,3,5-benzenetricarboxylic acid to the mixed solution is 3 mol:1 mol:20 L.

[0049] Then 0.5 g of PVP is dissolved in deionized water (solution B). The concentration of PVP is 0.05 g ml -1 .

[0050] Then solution A and solution B are stirred and mixed according to a volume ratio of 1:1. Take the mixed solution and transfer it to a 100 mL stainless steel Teflon-lined autoclave containing a piece of vertically placed foamed nickel, set the constant temperature air drying oven at 180°C and heat for 10 h, then rinse with ethanol and deionized water in sequence after cooling, and vacuum dry at 60°C. Cobalt-based metal organic framework nanosheet array (NF@Co-MOF NP) precursor grown on foamed nickel.

[0051] (3) Under ultrasonic conditions, take 6 mmol of organic sulfur-containing compound (the organic sulfur-containing compound is thiourea) and dissolve it in 20 mL of anhydrous ethanol, then transfer it to a reaction kettle containing vertically placed NF@Co-MOF NP, and set the constant temperature air drying oven at 180°C and heat for 5 h, then rinse with ethanol and deionized water in sequence after cooling, and vacuum dry to obtain NF@Co3S4 / (α,β)-NiS-180-5 catalyst.

[0052] Example 2

[0053] The same as example 1, except that:

[0054] The ultrasonic washing time in step (1) is 20 min;

[0055] In step (2), the molar ratio of cobalt nitrate hexahydrate to 1,3,5-benzenetricarboxylic acid is 2:1; in the mixed solution of N,N-dimethylformamide and ethanol, the volume ratio of N,N-dimethylformamide to ethanol is 2:1; the concentration of PVP in solution B is 0.1 g ml -1 . The volume ratio of solution A to solution B is 1:2. Vacuum drying at 70°C.

[0056] The time in the constant temperature air drying oven in step (3) is set to 3 h, and the other synthesis conditions remain unchanged, to obtain NF@Co3S4 / (α,β)-NiS-180-3 catalyst.

[0057] Example 3

[0058] The same as example 1,

[0059] The difference is that:

[0060] The ultrasonic washing time in step (1) is 20 min; the molar ratio of cobalt nitrate hexahydrate to 1,3,5-benzene tricarboxylic acid in step (2) is 4:1; the volume ratio of N,N-dimethylformamide to ethanol in the mixed solution of N,N-dimethylformamide and ethanol is 1:2; the concentration of PVP in solution B is 0.15 g / ml -1 . The volume ratio of solution A to solution B is 2:1. Vacuum drying at 80℃.

[0061] The organic sulfur-containing compound in step (3) is thioacetamide, and the concentration of the organic sulfur-containing compound is 4 mmol / L -1 .

[0062] The time in the constant-temperature blast drying oven in step (3) is set to 7 h, and the other synthesis conditions remain unchanged, to obtain the NF@Co3S4 / (α,β)-NiS-180-7 catalyst.

[0063] Example 4

[0064] The same as example 1,

[0065] The difference is that: the concentration of the organic sulfur-containing compound in step (3) is 5 mmol / L -1 .

[0066] The temperature in the constant-temperature blast drying oven in step (3) is set to 210℃, and the other synthesis conditions remain unchanged, to obtain the NF@Co3S4 / (α,β)-NiS-210-5 catalyst.

[0067] Example 5

[0068] The same as example 1,

[0069] The difference is that: the concentration of the organic sulfur-containing compound in step (3) is 5 mmol / L -1 .

[0070] The temperature in the constant-temperature blast drying oven in step (3) is set to 240℃, and the other synthesis conditions remain unchanged, to obtain the NF@Co3S4 / (α,β)-NiS-240-5 catalyst. Result analysis:

[0071] The material prepared in example 1 is subjected to structure characterization by X-ray diffraction (XRD), and the results are as follows Figure 1As shown in the XRD pattern of NF@Co3S4 / (α,β)-NiS-180-5, 31.48° and 55.14° correspond to the (311) and (440) characteristic planes of Co3S4, respectively, and 30.02°, 34.5° and 45.62° correspond to the (100), (101) and (102) characteristic planes of α-NiS, respectively. Interestingly, a small amount of β-NiS is also present, such as 32.26° corresponding to the (300) plane. This indicates that Co3S4, α-NiS and β-NiS coexist in the material, providing more active centers, confirming the successful synthesis of a heterogeneous material of Co3S4 and (α,β)-NiS.

[0072] The morphology of the material was further observed using a scanning electron microscope (SEM). Figure 2 As shown, NF@Co-MOF NPs exhibit a vertically distributed array of chrysanthemum-petal-shaped Co-MOF nanosheets forming hemispheres that coat the NF. During subsequent solvothermal treatment, thiourea releases sulfur-containing gases, causing the Co-MOF NPs to sulfide and change from purple to black. The formed NF@Co3S4 / (α,β)-NiS-180-5 retains traces of the precursor's hemispheres and exhibits a porous structure. Figure 3 a) Upon magnification, it was found that the clustered Co-MOF nanosheet array formed a smooth, cloud-like structure. Figure 3 b) The material is firmly embedded in the NF like a rivet, indicating that the vulcanization of the material was successful. Figure 4 The EDS mapping diagram of the obtained NF@Co3S4 / (α,β)-NiS-180-5 shows that Co, Ni, S and N elements are uniformly distributed on NF in the material.

[0073] Figure 5 The image shows the X-ray photoelectron spectroscopy (XPS) spectrum of the prepared NF@Co3S4 / (α,β)-NiS-180-5. Figure 5 The material contains species such as Ni, Co, O, N, C, and S. The Co 2p spectrum is shown in... Figure 5 Figure b shows four main peaks. Among them, the peaks at 778.59 eV (Co 2p3 / 2) and 793.23 eV (Co 2p1 / 2) are attributed to Co. 3+ 781.05 eV (Co 2p 3 / 2 ) and 796.57eV (Co 2p 1 / 2 The peak at point ) is attributed to Co. 2+ Related, and two satellite peaks were observed at 783.98 eV and 802.15 eV. S 2p high-resolution spectrum ( Figure 5c) fitted as four peaks, two peaks at 161.50 eV and 162.46 eV were observed corresponding to S 2p 3 / 2 and 2p 1 / 2 , 163.50 eV and 167.77 eV, respectively, indicating the presence of sulfur metal bond (S-M) in the material and the surface was oxidized to SO4 2- . In addition, Ni 2p XPS spectra Figure 5 d) fitted two spin-orbit peaks of Ni 2p 3 / 2 and Ni 2p 1 / 2 binding energies at 855.95 eV and 873.15 eV, respectively, clearly showed the Ni 0 peak, and 858.13 eV and 880.74 eV were attributed to satellite peaks. The results showed that the NF@Co3S4 / (α,β)-NiS-180-5 in-situ electrode material with unique flaky staggered stacking and multiple effective catalytic phases was successfully synthesized due to the induction of Co-MOF.

[0074] Example 6

[0075] The electrocatalytic oxidation performance of the catalyst material prepared by the above method was tested in a standard three-electrode electrolytic cell: the prepared NF@Co3S4 / (α,β)-NiS-180-5 was used as the working electrode, a Pt sheet was used as the counter electrode, and Ag / AgCl was used as the reference electrode. The scan range of linear sweep voltammetry (LSV) was 0.6-1.8 V vs RHE, and the scan rate was 5 mVs -1 . The frequency range of electrochemical impedance spectroscopy (EIS) was 0.1-106Hz. The electrochemically active surface area (ECSA) was estimated from the value of double-layer capacitance (C dl ) in the non-faradic region, and the range of the scan rate was 20-100 mVs -1 .

[0076] Figure 6 The linear sweep plots of the NF@Co3S4 / (α,β)-NiS-180-5 catalyst in the presence and absence of PPE in alkaline solution were recorded. As shown in the figure, when 1 mmol L -1 PPE was added, the potential corresponding to 10 mA cm -2 -2 moved negatively by 153 mV to 0.954 V vs the standard hydrogen electrode, indicating that it had higher activity for the electrocatalytic oxidation of PPE in thermodynamics. Figure 7 The impedance plot of the NF@Co3S4 / (α,β)-NiS-180-5 catalyst, after fitting by the (R(CR)W) equivalent circuit, its charge transfer resistance (R ct) is 0.61 Ω, which is less than other loading materials, indicating that the Co-MOF-directed synthesis of materials with smooth sheets and porous channels promotes the charge transfer rate of the electrode and electrolyte contact interface. Figure 8 The NF@Co3S4 / (a, b)-NiS-180-5 catalyst showed a capacitance value of 47.05 mF cm -2 , indicating that it has a large electrochemical surface area.

[0077] Subsequently, POR experiments were carried out using chronoamperometry with NF@Co3S4 / (a, b)-NiS-180-5 as the anode at a constant potential of 1.414 V vs RHE, and HPLC was used to monitor the conversion and the generation of benzoic acid. As shown in Figure 9 , the conversion efficiency of the substrate and the yield of the product benzoic acid reached 89.9 and 68.8%, respectively, after 7 h of electrooxidation, which were higher than those of other catalysts. In addition, as shown in Figure 10 , a high electrooxidation effect was still maintained in three consecutive cycles (8 h of electrolysis each time), demonstrating excellent stability. Given the above encouraging results, we coupled the HER and POR systems to study the possibility of reducing the water electrolysis potential using a platinum sheet as the cathode and NF@Co3S4 / (a, b)-NiS-180-5 as the anode. As shown in Figure 11 , the LSV curve of the two-electrode test, the potential at 10 mA cm -1 was reduced from 1.728 V to 1.515 V vs RHE after the addition of 1.0 mM PPE in 1.0 mol L -2 KOH. In addition, a large number of bubbles were generated at the cathode, while no bubbles were observed at the anode Figure 12 . The results show that POR is a successful alternative to the OER hydrogen production scheme.

Claims

1. A method for the preparation of a self-supported cobalt nickel bimetallic sulfide heterostructure anode electrocatalyst in the form of a foam of nickel for the electrooxidative conversion of a lignin model compound, 2-phenoxy-1-phenylethanol, in alkaline solution, characterized by, The method comprises the following steps: (1) The nickel foam NF is sequentially washed with acetone, 1-3 mol L -1 hydrochloric acid solution and deionized water, and vacuum dried; (2) Dissolve cobalt nitrate hexahydrate and 1,3,5-benzenetricarboxylic acid in a mixed solution of N,N-dimethylformamide and ethanol to obtain solution A; Then polyvinylpyrrolidone PVP is dissolved in deionized water to obtain solution B, Solution A and solution B are stirred and mixed to obtain a mixed solution; (3) A certain amount of the mixed solution is transferred into a high-pressure kettle containing NF, and the temperature is set to 170-190 DEG C in a constant-temperature drying oven and heated for 8-12 hours. After cooling, the product is washed with ethanol and deionized water in sequence and vacuum dried. The Co-MOF nanosheet array NF@Co-MOF NP precursor is grown on the foam nickel; (4) Under ultrasonic conditions, an organic sulfur-containing compound is dissolved in anhydrous ethanol, and then transferred into a reaction kettle containing a vertically placed NF@Co-MOF NP, and the temperature is set to 180-240 DEG C in a constant-temperature drying oven and heated for 3-7 hours. After cooling, the product is washed with ethanol and deionized water in sequence and vacuum dried. Finally, the foam nickel self-supported Co3S4 and (α,β)-NiS heterostructure electrocatalyst NF@Co3S4 / (α,β)-NiS is obtained.

2. The preparation method of claim 1, wherein In step (2), the molar ratio of cobalt nitrate hexahydrate to 1,3,5-benzenetricarboxylic acid is 2-4:1; the volume ratio of N,N-dimethylformamide to ethanol in the mixed solution is 0.5-2:1; The ratio of cobalt nitrate hexahydrate to 1,3,5-benzenetricarboxylic acid to the mixed solution is 2-4 mol:0.5-1.5 mol:20 L.

3. The preparation method of claim 1, wherein In step (2), the concentration of PVP is 0.04-0.06 g ml -1 ; The ratio of solution A to solution B is 0.5-2:

1.

4. The preparation method of claim 1, wherein The nickel foam NF in step (1) is sequentially cleaned with acetone, 1-3 mol L -1 hydrochloric acid solution and deionized water as cleaning agents for ultrasonic cleaning; the cleaning time of each cleaning agent is 10-30 min.

5. The preparation method of claim 1, wherein In step (3), the NF is vertically placed in the high-pressure kettle, and the high-pressure kettle is a stainless steel Teflon-lined high-pressure kettle. The organic sulfur-containing compound in step (4) is one of thiourea and thioacetamide; the concentration of the organic sulfur-containing compound is 3-6 mmol / L -1 .

6. The production method according to any one of claims 1 to 5, wherein The alkaline solution is one or both of a sodium hydroxide solution and a potassium hydroxide solution; and the concentration is 1 mol L -1 .

7. A foam nickel self-supported cobalt nickel bimetallic sulfide heterostructure anode electrocatalyst for the electrooxidative conversion of a lignin model compound, 2-phenoxy-1-phenylethanol in alkaline solution, characterized in that, Prepared by the preparation method of any one of claims 1-6.

8. Foam nickel self-supported Cobalt Nickel Bimetallic Sulfide Heterostructure Anode Electrocatalyst for the electrooxidative conversion of a lignin model compound, 2-phenoxy-1-phenylethanol in alkaline solution according to claim 7, characterized in that, The foam nickel wrapped with the Co-MOF nanosheet array is used as a sacrificial template, and the vertically grown nanosheets are connected to each other to form a cloud-like sheet-stacked block structure through a sulfurization process, and a cobalt-nickel bimetallic sulfide heterostructure is formed on the surface of the foam nickel.

9. Foam nickel self-supported Cobalt Nickel Bimetallic Sulfide Heterostructure Anode Electrocatalyst for the electrooxidative conversion of a lignin model compound, 2-phenoxy-1-phenylethanol in alkaline solution according to any one of claims 7 or 8, characterized in that, In the XRD pattern of NF@Co3S4 / (α,β)-NiS-180-5, 31.48° and 55.14° correspond to the (311) and (440) characteristic faces of Co3S4, and 30.02°, 34.5° and 45.62° correspond to the (100), (101) and (102) characteristic faces of α-NiS, respectively; Co3S4, α-NiS and β-NiS coexist.

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