Preparation method and application of nickel foam supported iron tungsten phosphorus doped nickel sulfide catalyst

Abstract

The present invention belongs to the technical field of electrocatalytic material preparation, and specifically relates to a method for preparing a nickel foam supported iron, tungsten and phosphorus doped nickel sulfide catalyst, comprising the following steps: 1) preparing a vacancy polyoxometalate K 12 H2P2W 12 O 48 ·24H2O, ferric chloride, a surfactant, and sodium sulfide are mixed to prepare an aqueous solution; 2) nickel foam is added to the aqueous solution prepared in step S1, and a nickel foam-supported iron, tungsten, and phosphorus-doped nickel sulfide catalyst is prepared by a one-step hydrothermal method. In the present invention, the vacancy polyacid acts synergistically with the iron salt and nickel foam to prepare a catalyst doped with three elements of iron, tungsten, and phosphorus, thereby achieving controllable doping of the nickel sulfide catalyst, and the catalyst in the present invention has high OER catalytic activity and good stability, and has high practical application value in the electrocatalytic oxygen evolution reaction.

Description

Technical Field

[0001] The invention belongs to the technical field of electrocatalytic material preparation, and specifically relates to a preparation method and application of a nickel foam-loaded iron-tungsten-phosphorus-doped nickel sulfide catalyst. Background Art

[0002] In recent years, environmental and energy issues have become hot topics in the field of scientific research. Various new electrochemical catalysts have been introduced, making electrochemistry shine in the fields of energy and environment. Among them, hydrogen energy has attracted much attention as a sustainable and storable clean energy. Using clean energy such as wind energy, solar energy, and tidal energy that are inconvenient to store to generate electricity, hydrogen is produced by electrolysis of water. Hydrogen generates energy through combustion or fuel cells, and the product is pure water, thus forming a green and environmentally friendly clean energy system. However, the electrolysis of water to produce hydrogen has the problems of high cost and high energy consumption, especially the high overpotential of the oxygen evolution reaction (ORE) at the anode, which affects the electrolysis efficiency. Although iridium-based and ruthenium-based catalysts have high OER activity, they are expensive and not suitable for large-scale industrial production. Therefore, it is necessary to develop and design catalysts with low design cost, excellent OER catalytic performance and stability.

[0003] Transition metal catalysts supported on nickel foam have good application prospects in the field of hydrogen production by electrolysis of water. Among many transition metal-based catalysts, nickel sulfide has low cost, high conductivity and good OER catalytic activity. However, compared with precious metal-based catalysts, the OER activity of nickel sulfide needs to be improved. Doping modification strategies can be used to improve the OER activity of nickel sulfide. For example, Chen et al. synthesized copper-doped nickel sulfide (Cu-Ni3S2 / NF) on nickel foam by a two-step hydrothermal method. When used as an anode material for water electrolysis, the electrode can reach 50 mA cm at an overpotential of 270 mV. -2 Lan et al. used a one-step solvothermal method to prepare a molybdenum-doped nickel sulfide electrocatalyst (Mo-Ni3S2 / NF), which only required an overpotential of 291 mV to provide 100 mA cm in the OER. -2 Li et al. used NiFe form to prepare an iron-doped nickel sulfide electrode in one step, which showed good OER activity with a current density of 100 mA cm -2 The overpotential is 290 mV. Therefore, effectively doping with highly active elements becomes an important way to enhance the catalytic activity of nickel sulfide, but there are few reports on the catalyst of nickel sulfide doped with multiple elements and the preparation method of the catalyst. Summary of the invention

[0004] The present invention aims to provide a method for preparing a nickel foam-supported iron, tungsten and phosphorus-doped nickel sulfide catalyst, in order to obtain an iron, tungsten and phosphorus co-doped nickel sulfide catalyst with high OER catalytic activity and strong stability, so as to apply it in the electrocatalytic oxygen evolution reaction.

[0005] In order to achieve the above object, the present invention provides a method for preparing a nickel foam supported iron tungsten phosphorus doped nickel sulfide catalyst, comprising the following steps:

[0006] S1, the vacant polyoxometalate K 12 H2P2W 12 O 48 ·24H2O, ferric chloride, surfactant and sodium sulfide are mixed to prepare an aqueous solution;

[0007] S2, adding nickel foam to the aqueous solution prepared in step S1, and preparing nickel foam-supported iron, tungsten and phosphorus-doped nickel sulfide catalyst by a one-step hydrothermal method.

[0008] Optionally, in step S1, the vacant polyoxometalate K 12 H2P2W 12 O 48 The concentration of 24H2O is 1.5-3.0 mmol / L, the concentration of ferric chloride is 30-50 mmol / L, the concentration of surfactant is 2-3 g / L, and the concentration of sodium sulfide is 60-120 mmol / L.

[0009] Optionally, in step S2, nickel foam and an aqueous solution are added to a reactor, and the reactor is sealed and placed in a water heating box for constant temperature reaction at 150°C for more than 5 hours. After the reaction is completed, the nickel foam is taken out, rinsed with water and ethanol several times in turn, and then dried at 60°C to obtain a nickel foam-loaded iron tungsten phosphorus doped nickel sulfide catalyst.

[0010] Optionally, in step S2, before adding the nickel foam to the aqueous solution prepared in step S1, the nickel foam is pretreated: the nickel foam is placed in a 3 M hydrochloric acid solution for ultrasonic treatment for 10 min, and then the nickel foam is transferred to pure water for ultrasonic treatment for 10 min. In this scheme, the nickel oxide layer and pollutants such as grease on the surface of the nickel foam are removed by pretreatment.

[0011] Optionally, in step S2, the nickel foam is cut into a size of 1 cm × 4 cm. The nickel foam in this solution can be placed upright in the reactor.

[0012] Optionally, in step S1, the surfactant is one or more of polyvinyl pyrrolidone, hexadecyltrimethylammonium bromide and sodium dodecyl sulfate.

[0013] The present invention also provides a nickel foam-loaded iron tungsten phosphorus-doped nickel sulfide catalyst prepared by the above preparation method. The nickel foam-loaded iron tungsten phosphorus-doped nickel sulfide catalyst has high OER catalytic activity and high stability, and can be applied to electrocatalytic oxygen evolution reaction.

[0014] The significant advantages and beneficial effects of this scheme are: in this scheme, the vacancy polyacid works synergistically with the iron salt and nickel foam to prepare a catalyst doped with three elements of iron, tungsten and phosphorus, and realizes the controllable doping of the nickel sulfide catalyst. In addition, the nickel foam loaded iron, tungsten and phosphorus doped nickel sulfide catalyst in this scheme has high OER catalytic activity and good stability. 2 The OER overpotential at a current density of 231 mV is therefore of high practical application value in the electrocatalytic oxygen evolution reaction. In addition, the preparation method of this scheme is simple in process, mild in conditions, low in cost, and has good industrial application value. This scheme utilizes the strong interaction between the vacancy polyacid {P2W12} and the iron ion, which helps to simultaneously incorporate several elements into the nickel sulfide structure. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a scanning electron microscope image of the nickel foam-supported iron-tungsten-phosphorus doped nickel sulfide catalyst in Example 1 of the present invention;

[0016] Figure 2 This is the EDS spectrum of the nickel foam-supported iron-tungsten-phosphorus doped nickel sulfide catalyst in Example 1 of the present invention;

[0017] Figure 3 The current-time curve of the 25-hour electrolysis of the nickel foam-supported iron-tungsten-phosphorus-doped nickel sulfide catalyst in Example 1 of the present invention;

[0018] Figure 4 It is a comparison diagram of the linear sweep voltammetric curves of the nickel foam supported iron tungsten phosphorus doped nickel sulfide catalyst in Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION

[0019] The following is further described in detail through specific implementation methods: Example

[0020] This embodiment provides a nickel sponge-supported iron-tungsten-phosphorus-doped nickel sulfide catalyst, and the preparation method of the nickel sponge-supported iron-tungsten-phosphorus-doped nickel sulfide catalyst comprises the following steps:

[0021] Weigh 0.315 g of vacancy polyoxometalate K 12 H2P2W 12 O 48·24H2O (abbreviated as {P2W12}), 0.540g FeCl3, 0.39g Na2S, 0.145g polyvinylpyrrolidone (PVP), pour the weighed reagents into a beaker and add 50mL of deionized water to dissolve, stir at room temperature for 1 min.

[0022] Wherein, the preparation method of {P2W12} is as follows:

[0023] Add 10 g Na2WO4·2H2O and 35 mL water to a round-bottom flask, heat to boiling after dissolving, slowly drop 15 mL 85% H3PO4, and add 1 mL H2O2 under stirring. Reflux the solution for 3 h. After cooling, add 10 g KCI solid and stir for 1 h to obtain a light yellow precipitate, which is filtered. Add a small amount of water, recrystallize, filter, cool in ice water, and filter. Purify again, dissolve with a small amount of 40 ℃ hot water (adjust pH to 2 with hydrochloric acid), cool, and evaporate at room temperature to precipitate yellow crystals K6[P2W 18 O 62 ]·14H2O, collect the crystals and dry them.

[0024] Take 83 g K6[P2W in a beaker 18 O 62 ]·14H2O sample was dissolved in 300 mL of water, 48.4 g of tris(hydroxymethyl)aminomethane was dissolved in 200 ml of water and added to the above 300 mL of aqueous solution to obtain a mixed solution. The mixed solution was allowed to stand at room temperature for 0.5 h, and then 80 g of potassium chloride was added. After complete dissolution, 55.3 g of potassium carbonate was added to 200 mL of water, and the 200 mL potassium carbonate aqueous solution was added to the above mixed solution, vigorously stirred for 15 min, and the white precipitate that appeared after a few minutes was filtered on a sand core funnel, filtered for 12 h, washed with 50 mL of ethanol for 2 to 3 min, and finally air-dried for 3 days to obtain K 12 H2P2W 12 O 48 ·24H2O.

[0025] 1) Pretreatment of nickel foam: Cut the nickel foam into a 1 cm × 4 cm rectangle and place it in a beaker containing 3 M hydrochloric acid solution for ultrasonic treatment for 10 min. Then transfer the nickel foam to a beaker containing pure water and ultrasonically treat it for 10 min.

[0026] 2) Hydrothermal reaction: Put two pre-treated nickel foams into a reactor, and pour the aqueous solution prepared in step 1 into the reactor in time, then seal the reactor, place the reactor in an oven, and react at 150°C for 6 hours. After the reaction is completed, cool to room temperature and take out the reacted nickel foam.

[0027] 3) Cleaning and drying: The nickel foam after the reaction was rinsed with deionized water and anhydrous ethanol three times in turn to clean the impurities on the nickel foam after the reaction. Then, it was dried in a vacuum drying oven at 60°C to obtain a nickel foam-supported iron-tungsten-phosphorus doped nickel sulfide catalyst, referred to as Fe{P2W12}-Ni3S2@NF.

[0028] The electron microscope scanning results of the nickel foam supported iron tungsten phosphorus doped nickel sulfide catalyst in this embodiment are as follows: Figure 1 As shown in the figure, it can be seen that the catalyst grows a uniformly dispersed nanostructure on the surface of nickel foam. Its EDS spectrum is shown in Figure 2 As shown, the catalyst contains Fe, W, Ni, P, and S, which indicates that the catalyst doped with three elements of iron, tungsten, and phosphorus is successfully prepared in this embodiment; Figure 3 It can be seen that the nickel foam supported iron tungsten phosphorus doped nickel sulfide catalyst in this embodiment has a stable current density during the 25 h electrolysis process, and the current fluctuation range fluctuates between 55.49 mA and 50.84 mA, with a small fluctuation range, which proves its high stability. In addition, the nickel foam supported iron tungsten phosphorus doped nickel sulfide catalyst in this embodiment is clamped with a platinum electrode clamp as a working electrode, a Pt sheet as a counter electrode, Hg / HgO as a reference electrode, and an electrolyte of 1 M KOH. After connecting with an electrochemical workstation, linear voltammetry is performed for scanning, as shown in FIG. Figure 4 As shown, at 100 mA / cm 2 The OER overpotential of Fe{P2W12}-Ni3S2@NF catalyst is 231 mV at a current density of . Example

[0029] The difference between this embodiment and embodiment 1 is that the amount of {P2W12} weighed in step 1 of this embodiment is different from the amount of {P2W12} weighed in step 1 of embodiment 1, and the rest are the same. Specifically, in step 1 of this embodiment, the amount of {P2W12} weighed is 0.285 g.

[0030] The nickel foam loaded with iron tungsten phosphorus doped nickel sulfide catalyst in this embodiment was clamped with a platinum electrode clamp as the working electrode, the Pt sheet as the counter electrode, Hg / HgO as the reference electrode, and the electrolyte as 1 M KOH. After connecting with an electrochemical workstation, linear voltammetry was performed for scanning at 100 mA / cm 2 The OER overpotential at a current density of 248 mV. Example

[0031] The difference between this embodiment and embodiment 1 is that the amount of {P2W12} weighed in step 1 of this embodiment is different from the amount of {P2W12} weighed in step 1 of embodiment 1, and the rest are the same. Specifically, in step 1 of this embodiment, the amount of {P2W12} weighed is 0.570 g.

[0032] The nickel foam loaded with iron tungsten phosphorus doped nickel sulfide catalyst in this embodiment was clamped with a platinum electrode clamp as the working electrode, the Pt sheet as the counter electrode, Hg / HgO as the reference electrode, and the electrolyte as 1 M KOH. After connecting with an electrochemical workstation, linear voltammetry was performed for scanning at 100 mA / cm 2 The OER overpotential at a current density of 237 mV.

[0033] The difference between this example and Example 1 is that step 1 of this comparative example is different from step 1 of Example 1, and the rest is the same. Specifically, step 1 of this comparative example is as follows:

[0034] Weigh 0.315 g of reagent H3O 40 PW 12 ·xH2O{PW12}, 0.540 g FeCl3, 0.39 g Na2S, 0.145 g polyvinylpyrrolidone (PVP), pour the weighed reagent into a beaker and add 50 mL of deionized water to dissolve, stir at room temperature for 1 min. Among them, {PW12} is a commercially available product purchased, specifically the phosphotungstic acid hydrate product produced by McLean Enterprises.

[0035] The nickel foam supported iron tungsten phosphorus doped nickel sulfide catalyst in this comparative example is referred to as Fe{PW12}-Ni3S2@NF. In this comparative example, the nickel foam supported iron tungsten phosphorus doped nickel sulfide catalyst in this comparative example is clamped with a platinum electrode clamp as a working electrode, a Pt sheet is a counter electrode, Hg / HgO is a reference electrode, and the electrolyte is 1 M KOH. After connecting with an electrochemical workstation, linear voltammetry is performed for scanning, such as Figure 4 As shown, at 100 mA / cm 2 The OER overpotential at a current density of 2.5 Å is 269 mV.

[0036] The above are only embodiments of the present invention. The invention is not limited to the fields involved in this implementation case. The common sense such as the known specific structures and characteristics in the scheme is not described in detail here. The ordinary technicians in the relevant field know all the common technical knowledge in the technical field to which the invention belongs before the application date or priority date, can obtain all the existing technologies in the field, and have the ability to apply the conventional experimental means before that date. The ordinary technicians in the relevant field can improve and implement this scheme in combination with their own abilities under the enlightenment given by this application. Some typical known structures or known methods should not become obstacles for ordinary technicians in the relevant field to implement this application. It should be pointed out that for those skilled in the art, without departing from the structure of the present invention, several deformations and improvements can be made, which should also be regarded as the protection scope of the present invention, which will not affect the effect of the implementation of the present invention and the practicality of the present invention. The protection scope required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to explain the content of the claims.

Claims

1. A method for preparing a nickel foam-supported iron-tungsten-phosphorus-doped nickel sulfide electrocatalytic oxygen evolution catalyst, characterized in that: The following steps are involved: S1, the vacant polyoxometalate K 12 H2P2W 12 O 48 ·24H2O, ferric chloride, surfactant and sodium sulfide are mixed to prepare an aqueous solution; S2, adding nickel foam to the aqueous solution prepared in step S1, and preparing nickel foam-supported iron, tungsten and phosphorus-doped nickel sulfide catalyst by a one-step hydrothermal method.

2. The method for preparing the nickel foam supported iron tungsten phosphorus doped nickel sulfide electrocatalytic oxygen evolution catalyst according to claim 1, characterized in that: In step S1, the vacant polyoxometalate K 12 H2P2W 12 O 48 The concentration of 24H2O is 1.5-3.0 mmol / L, the concentration of ferric chloride is 30-50 mmol / L, the concentration of surfactant is 2-3 g / L, and the concentration of sodium sulfide is 60-120 mmol / L.

3. The method for preparing the nickel foam supported iron tungsten phosphorus doped nickel sulfide electrocatalytic oxygen evolution catalyst according to claim 1, characterized in that: In step S2, nickel foam and aqueous solution are added into a reactor, and then the reactor is sealed and placed in a water heating box for constant temperature reaction at 150°C for more than 5 hours. After the reaction is completed, the nickel foam is taken out, rinsed with water and ethanol several times in turn, and then dried at 60°C to obtain a nickel foam-loaded iron tungsten phosphorus doped nickel sulfide catalyst.

4. The method for preparing the nickel foam supported iron tungsten phosphorus doped nickel sulfide electrocatalytic oxygen evolution catalyst according to claim 1, characterized in that: In step S2, before adding the nickel foam to the aqueous solution prepared in step S1, the nickel foam is pretreated: the nickel foam is placed in a 3 M hydrochloric acid solution for ultrasonic treatment for 10 min, and then the nickel foam is transferred to pure water for ultrasonic treatment for 10 min.

5. The method for preparing the nickel foam supported iron tungsten phosphorus doped nickel sulfide electrocatalytic oxygen evolution catalyst according to claim 1, characterized in that: In step S2, the nickel foam is cut into a size of 1 cm × 4 cm.

6. The method for preparing the nickel foam supported iron tungsten phosphorus doped nickel sulfide electrocatalytic oxygen evolution catalyst according to claim 1, characterized in that: In step S1, the surfactant is one or more of polyvinyl pyrrolidone, hexadecyltrimethylammonium bromide and sodium dodecyl sulfate.

7. A nickel foam supported iron-tungsten-phosphorus doped nickel sulfide electrocatalytic oxygen evolution catalyst prepared by the preparation method according to any one of claims 1 to 6.

8. Use of the nickel foam supported iron, tungsten and phosphorus doped nickel sulfide electrocatalytic oxygen evolution catalyst prepared by the preparation method according to any one of claims 1 to 6 in an electrocatalytic oxygen evolution reaction.

Images