Preparation method of CoFP / NF nanoflower catalyst and application of CoFP / NF nanoflower catalyst in seawater electrolysis

Abstract

The invention relates to a preparation method of a CoFP / NF nanoflower catalyst and application of the CoFP / NF nanoflower catalyst in seawater electrolysis, and belongs to the technical field of electrocatalyst.The preparation method comprises the following steps that a cobalt source, a fluorine source and an organic solvent are dissolved in deionized water, and a mixed solution is formed; adding pretreated foamed nickel into the mixed solution, carrying out hydrothermal reaction, then cooling at room temperature to obtain reacted foamed nickel, washing with water and absolute ethyl alcohol, and then drying; and phosphorizing the dried foamed nickel under hydrogen-argon anti-oxidation protective gas, preserving heat, and cooling to room temperature along with the furnace to obtain the catalyst which is recorded as CoFP / NF. The method provided by the invention is simple in process and good in controllability, the raw materials are cheap and wide in source, the obtained nanoflower particles are uniform in particle size and have high dispersity and active sites, the reaction rate and efficiency of electro-catalysis are improved, and relatively high catalytic activity and excellent stability are obtained, so that the preparation cost of the catalyst is reduced, and the preparation cost of the catalyst is reduced. The electrochemical performance of the catalyst is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of electrocatalysis, and in particular relates to a preparation method of a CoFP / NF nanoflower catalyst and an application thereof in the electrolysis of seawater. Background Art

[0002] The extensive use of traditional fossil fuels has led to severe energy crises and environmental pollution, significantly spurring the development of innovative technologies such as energy conversion and renewable energy storage. Hydrogen is one of the cleanest sustainable energy sources of the 21st century. Its abundant resources, low carbon footprint, and wide application have earned it the reputation of the "ultimate energy source" of the 21st century. It is an ideal alternative to fossil fuels and is gradually becoming a key enabler of global energy transition. Hydrogen (H2) has a high mass energy density and can be produced using a variety of methods. However, current H2 production methods, such as coal gasification and steam methane reforming, all generate carbon emissions. In comparison, water electrolysis is a simpler and more environmentally friendly process. There are three main routes for producing hydrogen through water electrolysis: alkaline water electrolysis (AWE), proton exchange membrane electrolysis (PEM), and solid oxide electrolysis (SOEC). Alkaline water electrolysis has achieved commercialization and is more mature, cost-effective, and economical than the other two technologies. It can adapt to the volatility of renewable energy generation, has high hydrogen production efficiency, and holds great promise for future development. However, the water used in the above methods is all fresh water, and the proportion of fresh water on the earth is far less than that of seawater. Therefore, the prospect of using seawater for electrolysis to produce hydrogen is very broad, and direct electrolysis of seawater to produce hydrogen has become a hot research direction in hydrogen production technology.

[0003] Hydrogen production from seawater electrolysis involves two half-reactions: the anodic oxygen evolution reaction (OER) and the cathodic hydrogen evolution reaction (HER). This reaction system is generally most favorable for the use of precious metal catalysts, such as platinum and ruthenium. However, the scarcity and cost of these metals severely hinder their widespread application. Therefore, the development of efficient, stable, and inexpensive electrocatalysts to replace precious metals for hydrogen and oxygen evolution reactions is crucial to promote the development of water splitting.

[0004] Against this backdrop, the present invention synthesizes a CoFP / NF material with a unique nanoflower morphology on nickel foam via a hydrothermal method and phosphating. The open-channel nature of the nanostructure shortens the ion diffusion pathway, facilitating electrolyte penetration and gas release. The interaction between the nanostructure and electrons ensures a low charge transfer resistance at the electrode-electrolyte boundary, helping to improve the material's stability against corrosive seawater. This invention utilizes transition metal doping to rationally design a multifunctional electrode material with high catalytic performance, aiming to provide a new method for large-scale H2 production by direct electrolysis of seawater. Summary of the Invention

[0005] In response to the shortcomings of the existing technology, the present invention provides a method for preparing CoFP / NF nanoflower catalysts and their application in the electrolysis of seawater. The method has a simple process and good controllability. Its raw materials are cheap and widely available. The obtained nanoflower particles have uniform particle size, high dispersibility and active sites, which improves the reaction rate and efficiency of electrocatalysis, obtains high catalytic activity and excellent stability, thereby reducing the cost of catalyst production while improving the electrochemical performance of the catalyst.

[0006] A method for preparing a CoFP / NF nanoflower catalyst specifically comprises the following steps:

[0007] (1) dissolving a cobalt source, a fluorine source, and an organic solvent in deionized water to form a mixed solution;

[0008] The cobalt source is Co(NO3)2·6H2O, CoSO4·7H2O and C 32 H 16 A mixture of CoN8, the fluorine source is a mixture of NH4F, NaF and C6H5F, and the organic solvent is a mixture of ethanolamine and ethylenediamine;

[0009] (2) adding the pretreated nickel foam to the mixed solution obtained in step (1), performing a hydrothermal reaction, and then cooling at room temperature to obtain a reacted nickel foam;

[0010] (3) washing the nickel foam obtained in step (2) with water, then washing with anhydrous ethanol, and then drying;

[0011] (4) The nickel foam dried in step (3) is placed in the center of a high-temperature tubular furnace, a phosphorus source is placed upstream, and phosphating is performed under a hydrogen-argon anti-oxidation protective gas, followed by heat preservation. The catalyst is cooled to room temperature with the furnace to obtain a catalyst, which is recorded as CoFP / NF.

[0012] in:

[0013] In the step (1), Co(NO3)2·6H2O, CoSO4·7H2O and C 32 H 16 The molar ratio of CoN8 is (3-4): (1-3): 0.1, and the concentration of the cobalt source in the mixed solution is 0.092 mol / L-0.106 mol / L.

[0014] In the step (1), the molar ratio of NH4F, NaF and C6H5F is (1-4):1:0.1, and the concentration of the fluorine source in the mixed solution is 0.075 mol / L-0.236 mol / L.

[0015] In the step (1), both ethanolamine and ethylenediamine are analytically pure, the volume ratio of ethanolamine to ethylenediamine is (1-3):1, and the concentration of the organic solvent in the mixed solution is 0.99 mol / L-1.45 mol / L.

[0016] In the step (1), the molar ratio of the cobalt source to the fluorine source is (2.9-3.4): (2.4-7.5), and the ratio of the total molar amount of the cobalt source and the fluorine source to the volume of the organic solvent is (5.3-9.9): (2-3) (mmol:mL).

[0017] In the step (2), the size of the nickel foam is (2 cm to 3 cm) × (2 cm to 3 cm), and the pretreatment process of the nickel foam is: ultrasonically treating the nickel foam in 1 mol / L HCl solution, deionized water, and anhydrous ethanol for 1 h to 2 h, respectively, and vacuum drying at 60° C. for 6 h to 8 h.

[0018] In the step (2), the hydrothermal reaction temperature is 130° C. to 160° C., and the reaction time is 5 h to 8 h.

[0019] In the step (3), the washed nickel foam is dried in a vacuum drying oven at 60° C. for 6 to 8 hours.

[0020] In the step (4), the phosphorus source is a mixture of NaH2PO2 powder and K3PO4 powder, and the molar ratio of NaH2PO2 to K3PO4 is (1-3):1.

[0021] In the step (4), the hydrogen-argon anti-oxidation protective gas is a mixed gas of Ar and H2, and the volume ratio of Ar to H2 is (19-49):1.

[0022] In the step (4), the phosphating process is specifically as follows: heating the tubular furnace to 350° C. to 450° C. at a heating rate of 2° C. / min to 5° C. / min, and keeping the temperature for 2 h to 4 h.

[0023] The application of the above-mentioned CoFP / NF nanoflower catalyst in seawater electrolysis includes the following steps:

[0024] The nanoflower catalyst CoFP / NF was tested on an Ivium VC electrochemical station for electrochemical hydrogen evolution reaction and oxygen evolution reaction: CoFP / NF catalyst was used as the working electrode, Hg / HgO electrode as the reference electrode, and Pt electrode as the counter electrode. All electrochemical oxygen reduction reaction measurements used 1 mol / L KOH and 1 mol / L NaCl solutions as electrolytes.

[0025] For HER, achieving 10 mA cm -2 The overpotential required for the current density of 106mV to 125mV is 106mV to 125mV; for OER, the overpotential required for the current density of 100mA cm-2 The overpotential required for the current density is 350mV~371mV; and the nanoflower catalyst CoFP / NF can maintain 89h~100h at a voltage of 1.3V.

[0026] Compared with the prior art, the present invention has the following beneficial effects:

[0027] 1. The nanoflowers synthesized by the hydrothermal method and phosphating in the present invention have a highly microporous structure and a large specific surface area, providing abundant active sites and adsorption sites, which are conducive to the catalytic reaction.

[0028] 2. The self-supporting characteristics of the nanoflower structure of the present invention can alleviate the stress caused by volume change during electrolysis, and the prepared catalyst has good structural stability and corrosion resistance.

[0029] 3. The present invention does not require the use of a binder, thus avoiding the negative impact of insulating binders on conductivity and simplifying the electrode preparation process, thereby ensuring the mechanical stability of the electrode.

[0030] 4. This invention uses a suitable conductive substrate, nickel foam (NF), to fabricate a three-dimensional, self-supporting nanostructure to further enhance catalytic activity. Rational design and precise, controllable construction of the three-dimensional, self-supporting nanostructure not only facilitate analysis of the reaction process but also effectively enhance the catalytic activity of the transition metal particles. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 SEM image of the catalyst obtained in Example 1 of the present invention;

[0032] Figure 2 HER curve of the catalyst obtained in Example 1 of the present invention;

[0033] Figure 3 OER curve of the catalyst obtained in Example 1 of the present invention;

[0034] Figure 4 CA curve of the catalyst obtained in Example 1 of the present invention. DETAILED DESCRIPTION

[0035] In the embodiment of the present invention, the cobalt source, fluorine source, phosphorus source and nickel foam used are all added in solid form, and ethanolamine and ethylenediamine are of analytical grade.

[0036] In the embodiment of the present invention, the pretreatment process of nickel foam is as follows: the nickel foam is ultrasonically treated in 1 mol / L HCl solution, deionized water, and anhydrous ethanol for 1 h respectively, and then vacuum dried at 60° C. for 6 h.

[0037] Example 1

[0038] A method for preparing a CoFP / NF nanoflower catalyst specifically comprises the following steps:

[0039] (1) Combine 0.00147mol Co(NO3)2·6H2O, 0.00147mol CoSO4·7H2O, 0.0000490molC 32 H 16 CoN8, 0.00218 mol NH4F, 0.00218 mol NaF, 0.000218 mol C6H5F, 1 mL ethanolamine, and 1 mL ethylenediamine were dissolved in deionized water to form a mixed solution; wherein the concentration of the cobalt source in the mixed solution was 0.093 mol / L, the concentration of the fluorine source in the mixed solution was 0.143 mol / L, and the concentration of the organic solvent in the mixed solution was 0.99 mol / L.

[0040] (2) A pre-treated nickel foam of 2 cm×2 cm was added to the mixed solution obtained in step (1) to perform a hydrothermal reaction at a temperature of 130° C. for 5 h, followed by cooling at room temperature to obtain a reacted nickel foam.

[0041] (3) The nickel foam obtained in step (2) was washed with water and then with anhydrous ethanol, and then dried in a vacuum drying oven at 60° C. for 6 h.

[0042] (4) The nickel foam dried in step (3) was placed in the center of a high-temperature tube furnace, and 0.00135 mol NaH2PO2 and 0.00135 mol K3PO4 were placed upstream. The temperature was raised to 350°C at a rate of 2°C / min in a mixed gas atmosphere of Ar and H2 with a volume ratio of 19:1. The temperature was kept at this temperature for 2 hours, and the catalyst was cooled to room temperature in the furnace to obtain a catalyst, which was designated as CoFP / NF. The SEM image of the prepared catalyst is shown in FIG. Figure 1 As shown, the HER curve is as follows Figure 2 As shown, the OER curve is as follows Figure 3 As shown, the CA curve is as follows Figure 4 shown.

[0043] The application of the above-mentioned CoFP / NF nanoflower catalyst in seawater electrolysis includes the following steps:

[0044] Nanoflower catalyst CoFP / NF was used as a catalyst for seawater electrolysis. Electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were tested on an Ivium VC electrochemical station. CoFP / NF catalyst was used as the working electrode, Hg / HgO electrode as the reference electrode, and Pt electrode as the counter electrode. All electrochemical oxygen reduction reaction measurements used 1 mol / L KOH and 1 mol / L NaCl solutions as the electrolyte.

[0045] For HER, achieving 10 mA cm -2 The overpotential required to achieve a current density of 106 mV for OER is 100 mA cm -2 The overpotential required for the current density is 350mV; and the nanoflower catalyst CoFP / NF can maintain a voltage of 1.3V for 100h.

[0046] Example 2

[0047] A method for preparing a CoFP / NF nanoflower catalyst specifically comprises the following steps:

[0048] (1) Combine 0.00216mol Co(NO3)2·6H2O, 0.00113mol CoSO4·7H2O, 0.0000720molC 32 H 16 CoN8, 0.00185 mol NH4F, 0.000615 mol NaF, 0.0000615 mol C6H5F, 1.5 mL ethanolamine, and 1 mL ethylenediamine were dissolved in deionized water to form a mixed solution; wherein the concentration of the cobalt source in the mixed solution was 0.103 mol / L, the concentration of the fluorine source in the mixed solution was 0.078 mol / L, and the concentration of the organic solvent in the mixed solution was 1.23 mol / L.

[0049] (2) A piece of pretreated nickel foam of 2 cm×2 cm was added to the mixed solution obtained in step (1) to perform a hydrothermal reaction at a temperature of 160° C. for 8 h, followed by cooling at room temperature to obtain a reacted nickel foam.

[0050] (3) The nickel foam obtained in step (2) was washed with water, then washed with anhydrous ethanol, and then dried in a vacuum drying oven at 60° C. for 8 h.

[0051] (4) The nickel foam dried in step (3) was placed in the center of a high-temperature tube furnace, and 0.002025 mol NaH2PO2 and 0.000675 mol K3PO4 were placed at the upstream position. The temperature was raised to 450°C at a rate of 3°C / min in a mixed gas of Ar and H2 with a volume ratio of 29:1, and the temperature was kept at this temperature for 4 h. The catalyst was cooled to room temperature with the furnace to obtain a catalyst, which was recorded as CoFP / NF.

[0052] The application of the above-mentioned CoFP / NF nanoflower catalyst in seawater electrolysis includes the following steps:

[0053] Nanoflower catalyst CoFP / NF was used as a catalyst for seawater electrolysis. Electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were tested on an Ivium VC electrochemical station. CoFP / NF catalyst was used as the working electrode, Hg / HgO electrode as the reference electrode, and Pt electrode as the counter electrode. All electrochemical oxygen reduction reaction measurements used 1 mol / L KOH and 1 mol / L NaCl solutions as the electrolyte.

[0054] For HER, achieving 10 mA cm -2 The overpotential required to achieve a current density of 100 mA cm for OER is 112 mV. -2 The overpotential required for the current density is 358mV; and the nanoflower catalyst CoFP / NF can maintain a voltage of 1.3V for 95h.

[0055] Example 3

[0056] A method for preparing a CoFP / NF nanoflower catalyst specifically comprises the following steps:

[0057] (1) Combine 0.00181mol Co(NO3)2·6H2O, 0.00121mol CoSO4·7H2O, 0.0000603molC 32 H 16 CoN8, 0.00159 mol NH4F, 0.00159 mol NaF, 0.000159 mol C6H5F, 2 mL of ethanolamine, and 1 mL of ethylenediamine were dissolved in deionized water to form a mixed solution; wherein the concentration of the cobalt source in the mixed solution was 0.093 mol / L, the concentration of the fluorine source in the mixed solution was 0.101 mol / L, and the concentration of the organic solvent in the mixed solution was 1.45 mol / L.

[0058] (2) A piece of pretreated nickel foam of 2 cm×2 cm was added to the mixed solution obtained in step (1) to perform a hydrothermal reaction at a temperature of 140° C. for 7 h, followed by cooling at room temperature to obtain a reacted nickel foam.

[0059] (3) The nickel foam obtained in step (2) was washed with water, then washed with anhydrous ethanol, and then dried in a vacuum drying oven at 60° C. for 7 h.

[0060] (4) The nickel foam dried in step (3) was placed in the center of a high-temperature tube furnace, and 0.0018 mol NaH2PO2 and 0.0009 mol K3PO4 were placed at the upstream position. The temperature was raised to 400°C at a rate of 5°C / min in a mixed gas of Ar and H2 with a volume ratio of 29:1, and the temperature was kept at this temperature for 3 h. The catalyst was cooled to room temperature with the furnace to obtain a catalyst, which was recorded as CoFP / NF.

[0061] The application of the above-mentioned CoFP / NF nanoflower catalyst in seawater electrolysis includes the following steps:

[0062] Nanoflower catalyst CoFP / NF was used as a catalyst for seawater electrolysis. Electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were tested on an Ivium VC electrochemical station. CoFP / NF catalyst was used as the working electrode, Hg / HgO electrode as the reference electrode, and Pt electrode as the counter electrode. All electrochemical oxygen reduction reaction measurements used 1 mol / L KOH and 1 mol / L NaCl solutions as the electrolyte.

[0063] For HER, achieving 10 mA cm -2 The overpotential required to achieve a current density of 100 mA cm for OER is 121 mV. -2 The overpotential required for the current density is 369mV; and the nanoflower catalyst CoFP / NF can maintain a voltage of 1.3V for 91h.

[0064] Example 4

[0065] A method for preparing a CoFP / NF nanoflower catalyst specifically comprises the following steps:

[0066] (1) Combine 0.00198mol Co(NO3)2·6H2O, 0.000990mol CoSO4·7H2O, 0.0000660molC 32 H 16 CoN8, 0.00173 mol NH4F, 0.000694 mol NaF, 0.0000694 mol C6H5F, 1.5 mL ethanolamine, and 0.5 mL ethylenediamine were dissolved in deionized water to form a mixed solution; wherein the concentration of the cobalt source in the mixed solution was 0.095 mol / L, the concentration of the fluorine source in the mixed solution was 0.078 mol / L, and the concentration of the organic solvent in the mixed solution was 1.01 mol / L.

[0067] (2) A piece of pretreated nickel foam of 2 cm×2 cm was added to the mixed solution obtained in step (1) to perform a hydrothermal reaction at a temperature of 160° C. for 8 h, followed by cooling at room temperature to obtain a reacted nickel foam.

[0068] (3) The nickel foam obtained in step (2) was washed with water and then with anhydrous ethanol, and then dried in a vacuum drying oven at 60° C. for 6 h.

[0069] (4) The nickel foam dried in step (3) was placed in the center of a high-temperature tube furnace, and 0.0018 mol NaH2PO2 and 0.0009 mol K3PO4 were placed at the upstream position. The temperature was raised to 450°C at a rate of 5°C / min in a mixed gas of Ar and H2 with a volume ratio of 39:1, and the temperature was kept at this temperature for 3 h. The catalyst was cooled to room temperature with the furnace to obtain a catalyst, which was recorded as CoFP / NF.

[0070] The application of the above-mentioned CoFP / NF nanoflower catalyst in seawater electrolysis includes the following steps:

[0071] Nanoflower catalyst CoFP / NF was used as a catalyst for seawater electrolysis. Electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were tested on an Ivium VC electrochemical station. CoFP / NF catalyst was used as the working electrode, Hg / HgO electrode as the reference electrode, and Pt electrode as the counter electrode. All electrochemical oxygen reduction reaction measurements used 1 mol / L KOH and 1 mol / L NaCl solutions as the electrolyte.

[0072] For HER, achieving 10 mA cm -2 The overpotential required to achieve a current density of 100 mA cm for OER is 118 mV. -2 The overpotential required for the current density is 362mV; and the nanoflower catalyst CoFP / NF can maintain a voltage of 1.3V for 93h.

[0073] Example 5

[0074] A method for preparing a CoFP / NF nanoflower catalyst specifically comprises the following steps:

[0075] (1) Combine 0.00175mol Co(NO3)2·6H2O, 0.00117mol CoSO4·7H2O, 0.0000583molC 32 H 16 CoN8, 0.00185 mol NH4F, 0.000951 mol NaF, 0.0000951 mol C6H5F, 1.5 mL ethanolamine, and 0.5 mL ethylenediamine were dissolved in deionized water to form a mixed solution; wherein the concentration of the cobalt source in the mixed solution was 0.093 mol / L, the concentration of the fluorine source in the mixed solution was 0.0905 mol / L, and the concentration of the organic solvent in the mixed solution was 1.01 mol / L.

[0076] (2) A pre-treated nickel foam of 2 cm×2 cm was added to the mixed solution obtained in step (1) to perform a hydrothermal reaction at a temperature of 150° C. for 7 h, followed by cooling at room temperature to obtain a reacted nickel foam.

[0077] (3) The nickel foam obtained in step (2) was washed with water, then washed with anhydrous ethanol, and then dried in a vacuum drying oven at 60° C. for 7 h.

[0078] (4) The nickel foam dried in step (3) was placed in the center of a high-temperature tube furnace, and 0.002025 mol NaH2PO2 and 0.000675 mol K3PO4 were placed at the upstream position. The temperature was raised to 450°C at a rate of 2°C / min in a mixed gas of Ar and H2 with a volume ratio of 49:1, and the temperature was kept at this temperature for 4 h. The catalyst was cooled to room temperature with the furnace to obtain a catalyst, which was recorded as CoFP / NF.

[0079] The application of the above-mentioned CoFP / NF nanoflower catalyst in seawater electrolysis includes the following steps:

[0080] Nanoflower catalyst CoFP / NF was used as a catalyst for seawater electrolysis. Electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were tested on an Ivium VC electrochemical station. CoFP / NF catalyst was used as the working electrode, Hg / HgO electrode as the reference electrode, and Pt electrode as the counter electrode. All electrochemical oxygen reduction reaction measurements used 1 mol / L KOH and 1 mol / L NaCl solutions as the electrolyte.

[0081] For HER, achieving 10 mA cm -2 The overpotential required to achieve a current density of 100 mA cm for OER is 125 mV. -2 The overpotential required for the current density is 357mV; and the nanoflower catalyst CoFP / NF can maintain a voltage of 1.3V for 89h.

[0082] Example 6

[0083] A method for preparing a CoFP / NF nanoflower catalyst specifically comprises the following steps:

[0084] (1) Combine 0.00216mol Co(NO3)2·6H2O, 0.00112mol CoSO4·7H2O, 0.0000718molC 32 H 16 CoN8, 0.00163 mol NH4F, 0.000796 mol NaF, 0.0000796 mol C6H5F, 2 mL ethanolamine, and 1 mL ethylenediamine were dissolved in deionized water to form a mixed solution; wherein the concentration of the cobalt source in the mixed solution was 0.104 mol / L, the concentration of the fluorine source in the mixed solution was 0.0783 mol / L, and the concentration of the organic solvent in the mixed solution was 0.99 mol / L.

[0085] (2) A pre-treated nickel foam of 2 cm×2 cm was added to the mixed solution obtained in step (1) to perform a hydrothermal reaction at a temperature of 130° C. for 8 h, followed by cooling at room temperature to obtain a reacted nickel foam.

[0086] (3) The nickel foam obtained in step (2) was washed with water, then washed with anhydrous ethanol, and then dried in a vacuum drying oven at 60° C. for 8 h.

[0087] (4) The nickel foam dried in step (3) was placed in the center of a high-temperature tube furnace, and 0.0018 mol NaH2PO2 and 0.0009 mol K3PO4 were placed at the upstream position. The temperature was raised to 350°C at a rate of 5°C / min in a mixed gas of Ar and H2 with a volume ratio of 39:1, and the temperature was kept at this temperature for 3 h. The catalyst was cooled to room temperature with the furnace to obtain a catalyst, which was recorded as CoFP / NF.

[0088] The application of the above-mentioned CoFP / NF nanoflower catalyst in seawater electrolysis includes the following steps:

[0089] Nanoflower catalyst CoFP / NF was used as a catalyst for seawater electrolysis. Electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were tested on an Ivium VC electrochemical station. CoFP / NF catalyst was used as the working electrode, Hg / HgO electrode as the reference electrode, and Pt electrode as the counter electrode. All electrochemical oxygen reduction reaction measurements used 1 mol / L KOH and 1 mol / L NaCl solutions as the electrolyte.

[0090] For HER, achieving 10 mA cm -2 The overpotential required to achieve a current density of 100 mA cm for OER is 116 mV. -2 The overpotential required for the current density is 371mV; and the nanoflower catalyst CoFP / NF can maintain a voltage of 1.3V for 92h.

[0091] Example 7

[0092] A method for preparing a CoFP / NF nanoflower catalyst specifically comprises the following steps:

[0093] (1) Combine 0.00151mol Co(NO3)2·6H2O, 0.00147mol CoSO4·7H2O, 0.0000503molC 32 H 16CoN8, 0.00175 mol NH4F, 0.00175 mol NaF, 0.000175 mol C6H5F, 1.5 mL ethanolamine, and 1.5 mL ethylenediamine were dissolved in deionized water to form a mixed solution; wherein the concentration of the cobalt source in the mixed solution was 0.095 mol / L, the concentration of the fluorine source in the mixed solution was 0.111 mol / L, and the concentration of the organic solvent in the mixed solution was 1.43 mol / L.

[0094] (2) A pre-treated nickel foam of 2 cm×2 cm was added to the mixed solution obtained in step (1) to perform a hydrothermal reaction at a temperature of 150° C. for 8 h, followed by cooling at room temperature to obtain a reacted nickel foam.

[0095] (3) The nickel foam obtained in step (2) was washed with water, then washed with anhydrous ethanol, and then dried in a vacuum drying oven at 60° C. for 7 h.

[0096] (4) The nickel foam dried in step (3) was placed in the center of a high-temperature tube furnace, and 0.002025 mol NaH2PO2 and 0.000675 mol K3PO4 were placed at the upstream position. The temperature was raised to 450°C at a rate of 4°C / min in a mixed gas of Ar and H2 with a volume ratio of 49:1, and the temperature was kept at this temperature for 2 h. The catalyst was cooled to room temperature with the furnace to obtain a catalyst, which was recorded as CoFP / NF.

[0097] The application of the above-mentioned CoFP / NF nanoflower catalyst in seawater electrolysis includes the following steps:

[0098] Nanoflower catalyst CoFP / NF was used as a catalyst for seawater electrolysis. Electrochemical hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) were tested on an Ivium VC electrochemical station. CoFP / NF catalyst was used as the working electrode, Hg / HgO electrode as the reference electrode, and Pt electrode as the counter electrode. All electrochemical oxygen reduction reaction measurements used 1 mol / L KOH and 1 mol / L NaCl solutions as the electrolyte.

[0099] For HER, achieving 10 mA cm -2 The overpotential required to achieve a current density of 100 mA cm for OER is 123 mV. -2 The overpotential required for the current density is 364mV; and the nanoflower catalyst CoFP / NF can maintain a voltage of 1.3V for 96h.

[0100] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art will be able to modify the technical solutions described in the foregoing embodiments or to substitute equivalents for some of the technical features. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for preparing CoFP / NF nanoflower catalyst, characterized in that: The specific steps include: (1) dissolving a cobalt source, a fluorine source, and an organic solvent in deionized water to form a mixed solution; The cobalt source is Co(NO3)2·6H2O, CoSO4·7H2O and C 32 H 16 A mixture of CoN8, the fluorine source is a mixture of NH4F, NaF and C6H5F, and the organic solvent is a mixture of ethanolamine and ethylenediamine; (2) adding the pretreated nickel foam to the mixed solution obtained in step (1), performing a hydrothermal reaction, and then cooling at room temperature to obtain a reacted nickel foam; (3) washing the nickel foam obtained in step (2) with water, then washing with anhydrous ethanol, and then drying; (4) The nickel foam dried in step (3) is placed in the center of a high-temperature tubular furnace, a phosphorus source is placed upstream, and phosphating is performed under a hydrogen-argon anti-oxidation protective gas, followed by heat preservation. The catalyst is cooled to room temperature with the furnace to obtain a catalyst, which is recorded as CoFP / NF.

2. The method for preparing a CoFP / NF nanoflower catalyst according to claim 1, characterized in that: In the step (1), Co(NO3)2·6H2O, CoSO4·7H2O and C 32 H 16 The molar ratio of CoN8 is (3-4): (1-3): 0.1, and the concentration of the cobalt source in the mixed solution is 0.092 mol / L-0.106 mol / L.

3. The method for preparing a CoFP / NF nanoflower catalyst according to claim 1, characterized in that: In the step (1), the molar ratio of NH4F, NaF and C6H5F is (1-4):1:0.1, and the concentration of the fluorine source in the mixed solution is 0.075 mol / L-0.236 mol / L.

4. The method for preparing a CoFP / NF nanoflower catalyst according to claim 1, characterized in that: In the step (1), both ethanolamine and ethylenediamine are analytically pure, the volume ratio of ethanolamine to ethylenediamine is (1-3):1, and the concentration of the organic solvent in the mixed solution is 0.99 mol / L-1.45 mol / L.

5. The method for preparing a CoFP / NF nanoflower catalyst according to claim 1, characterized in that: In the step (1), the molar ratio of the cobalt source to the fluorine source is (2.9-3.4): (2.4-7.5), and the ratio of the total molar amount of the cobalt source and the fluorine source to the volume of the organic solvent is (5.3-9.9): (2-3) (mmol:mL).

6. The method for preparing a CoFP / NF nanoflower catalyst according to claim 1, characterized in that: In the step (2), the size of the nickel foam is (2 cm to 3 cm) × (2 cm to 3 cm), and the pretreatment process of the nickel foam is: ultrasonically treating the nickel foam in 1 mol / L HCl solution, deionized water, and anhydrous ethanol for 1 h to 2 h, respectively, and vacuum drying at 60° C. for 6 h to 8 h; the hydrothermal reaction temperature is 130° C. to 160° C., and the reaction time is 5 h to 8 h.

7. The method for preparing a CoFP / NF nanoflower catalyst according to claim 1, characterized in that: In the step (3), the washed nickel foam is dried in a vacuum drying oven at 60° C. for 6 to 8 hours.

8. The method for preparing a CoFP / NF nanoflower catalyst according to claim 1, characterized in that: In the step (4), the phosphorus source is a mixture of NaH2PO2 powder and K3PO4 powder, and the molar ratio of NaH2PO2 to K3PO4 is (1-3):1; the hydrogen-argon antioxidant protective gas is a mixed gas of Ar and H2, and the volume ratio of Ar to H2 is (19-49):1; the phosphating process is specifically as follows: the tubular furnace is heated to 350°C to 450°C at a heating rate of 2°C / min to 5°C / min, and kept warm for 2h to 4h.

9. A CoFP / NF nanoflower catalyst, characterized in that: The preparation method according to claim 1 is used to prepare the product.

10. The use of the CoFP / NF nanoflower catalyst in seawater electrolysis according to claim 9, characterized in that: The following steps are involved: The nanoflower catalyst CoFP / NF was tested on an Ivium VC electrochemical station for electrochemical hydrogen evolution reaction and oxygen evolution reaction: CoFP / NF catalyst was used as the working electrode, Hg / HgO electrode as the reference electrode, and Pt electrode as the counter electrode. All electrochemical oxygen reduction reaction measurements used 1 mol / L KOH and 1 mol / L NaCl solutions as electrolytes. For HER, achieving 10 mA cm -2 The overpotential required for the current density of 106mV to 125mV is 106mV to 125mV; for OER, the overpotential required for the current density of 100mA cm -2 The overpotential required for the current density is 350mV~371mV; and the nanoflower catalyst CoFP / NF can maintain 89h~100h at a voltage of 1.3V.

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