Application of phosphorus nickel in the process of hydrogen production by electrolysis of water

Abstract

The application discloses application of phosphorus nickel in a hydrogen production process by electrolysis of water, and the phosphorus nickel is prepared by the following method: dissolving a nickel metal salt in water to prepare a nickel metal salt aqueous solution; heating tetrabutylammonium hydroxide to melting to obtain a tetrabutylammonium hydroxide melt; adding the nickel metal salt aqueous solution into the tetrabutylammonium hydroxide melt, and reacting under heating to generate a flaky nickel-containing precursor; under the protection of a protective atmosphere, phosphorizing the flaky nickel-containing precursor with a phosphorus source to generate the phosphorus nickel in a flaky structure, which has low crystallinity and excellent hydrogen evolution catalytic activity, and can be applied in the field of hydrogen production by electrolysis of water, and has excellent hydrogen evolution effect.

Description

[0001] This invention is a divisional application of Chinese Patent Application No. 2024101827956, filed on February 19, 2024, entitled "Nitrile Phosphide Catalyst and its Preparation Method and its Application in Electrocatalytic Hydrogen Evolution Process". Technical Field

[0002] This invention relates to the field of catalysts, and more particularly to transition metal phosphide catalysts and their application in the electrocatalytic hydrogen evolution process, specifically to the application of nickel phosphide (Ni2P) with low crystallinity and a lamellar structure in the process of hydrogen production by water electrolysis. Background Technology

[0003] Electrochemical water splitting is considered one of the most promising hydrogen production methods. However, the slow kinetics of the oxygen evolution reaction (OER) severely limit hydrogen production efficiency. To realize the industrial application of water electrolysis systems, we need to find catalysts with low overpotential, high activity, and high durability to reduce energy costs. Nickel phosphide (Ni₂P) has advantages such as high catalytic activity, good chemical stability, simple preparation process, and low cost, making it a promising hydrogen evolution material. However, its poor electrical conductivity and limited surface active sites mean that currently used nickel phosphide (Ni₂P) catalysts still suffer from high overpotentials, and their hydrogen evolution catalytic activity needs improvement. Therefore, further reducing the OER overpotential and improving the activity of OER catalysts remains a challenge. Summary of the Invention

[0004] The purpose of this invention is to overcome one or more shortcomings in the prior art and provide a low-crystallinity, plate-like structure nickel phosphide (Ni2P) for use in the electrolysis of water to produce hydrogen, which has excellent hydrogen evolution effect.

[0005] To achieve the above objectives, one technical solution adopted by the present invention is: a method for preparing a nickel phosphide catalyst, the preparation method comprising:

[0006] A nickel metal salt is dissolved in water to prepare an aqueous solution of nickel metal salt;

[0007] Tetrabutylammonium hydroxide is heated to melt to obtain tetrabutylammonium hydroxide melt;

[0008] The aqueous solution of the nickel metal salt is added to the molten tetrabutylammonium hydroxide according to a preset ratio, and the mixture is reacted under heating conditions to generate a sheet-like nickel-containing precursor; wherein, the preset ratio is used to control the average content of nickel metal salt in each gram of the molten tetrabutylammonium hydroxide to be 4.5 × 10⁻⁶. -9 ~1.5×10 -3The volume ratio of the aqueous solution of the nickel metal salt to the mass of the tetrabutylammonium hydroxide melt is 0.025-0.8, expressed in mL / g.

[0009] Under a protective atmosphere, a phosphorus source is subjected to a phosphating reaction with the sheet-like nickel-containing precursor to generate the nickel phosphide catalyst, which has a sheet-like structure.

[0010] According to some preferred and specific aspects of the invention, the nickel metal salt may include, but is not limited to, one or more combinations selected from nickel acetate, nickel nitrate, nickel chloride, and nickel sulfate.

[0011] According to some preferred aspects of the invention, the mass concentration of the nickel metal salt in the aqueous solution is 0.02-2.0 g / L. This concentration control is beneficial for providing a suitable mass concentration and for ensuring that the melt remains the primary solvent during subsequent contact with the tetrabutylammonium hydroxide melt, thus guiding the reaction in the desired direction.

[0012] According to some preferred aspects of the invention, the ratio of the volume of the nickel metal salt aqueous solution to the mass of the tetrabutylammonium hydroxide melt is 0.04-0.6, in mL / g.

[0013] According to some specific aspects of the present invention, the heating temperature is controlled to be 80-120°C.

[0014] In some preferred embodiments of the present invention, the preparation of the sheet-like nickel-containing precursor includes: injecting the aqueous solution of the nickel metal salt into the tetrabutylammonium hydroxide melt according to a preset ratio, heating in an oil bath at 80-120°C, stirring the reaction, washing after the reaction is complete, and vacuum drying to obtain the sheet-like nickel-containing precursor. In the present invention, the injection method is more advantageous for obtaining the sheet-like nickel-containing precursor.

[0015] In some embodiments of the present invention, the washing process in preparing the sheet-like nickel-containing precursor is performed using an alcohol solvent. Further, the alcohol solvent may include, but is not limited to, ethanol.

[0016] According to some specific aspects of the invention, the phosphorus source includes, but is not limited to, one or more combinations selected from hypophosphite, phosphate, white phosphorus and red phosphorus.

[0017] In some embodiments of the present invention, the hypophosphite is sodium dihydrogen hypophosphite and / or potassium dihydrogen hypophosphite, and the phosphate is sodium phosphate and / or potassium phosphate.

[0018] According to some preferred aspects of the invention, the amount of phosphorus source added is excessive relative to the amount of nickel-containing flake precursor fed.

[0019] Furthermore, the ratio of the added molar amount of phosphorus source to the added molar amount of the flake-shaped nickel-containing precursor is 2.1-60:1.

[0020] According to some preferred aspects of the invention, the phosphating reaction is controlled to be carried out at 280-330°C.

[0021] According to some specific aspects of the invention, the reaction time of the phosphating reaction is controlled to be 1-4 hours.

[0022] In some preferred embodiments of the present invention, the preparation of the nickel phosphide catalyst includes: under a protective atmosphere, placing the phosphorus source upstream of the incoming protective gas flow, placing the sheet-like nickel-containing precursor downstream of the incoming protective gas flow, heating to a preset reaction temperature, maintaining the temperature for reaction, washing after the reaction is completed, and vacuum drying to obtain the nickel phosphide catalyst.

[0023] In some embodiments of the present invention, the preset reaction temperature is 280-330°C.

[0024] In some embodiments of the present invention, the temperature of the vacuum drying is 20-80°C.

[0025] In some embodiments of the present invention, during the preparation of the nickel phosphide catalyst, the washing is performed using water and an alcohol solvent, respectively. Further, the alcohol solvent may include, but is not limited to, ethanol.

[0026] In some embodiments of the present invention, the protective gas may be nitrogen or an inert gas, such as argon or helium.

[0027] According to certain aspects of the present invention, the method of the present invention can prepare products with smaller dimensions. Specifically, in some embodiments, the nickel phosphide catalyst with a sheet-like structure has a thickness of 1-5 nm and a two-dimensional planar dimension of 5-20 nm. In the present invention, when the sheet-like structure is circular, the two-dimensional planar dimension is the diameter; when the sheet-like structure is elliptical, the two-dimensional planar dimension is the length of the major axis; and when the sheet-like structure is square, the two-dimensional planar dimension is the length.

[0028] Another technical solution provided by the present invention: a nickel phosphide catalyst prepared by the above-described method for preparing nickel phosphide catalyst.

[0029] The nickel phosphide catalyst prepared by the method of this invention not only has a small-sized plate-like structure, but also has low crystallinity.

[0030] Another technical solution provided by the present invention: the application of the above-mentioned nickel phosphide catalyst as a water electrolysis catalyst in the electrocatalytic hydrogen evolution process.

[0031] According to some specific aspects of the invention, the application includes: electrocatalytic hydrogen evolution in an acidic electrolyte, alkaline electrolyte, or neutral electrolyte.

[0032] In this invention, the specific reaction equipment and external setup are not particularly limited. Examples include common solution reaction apparatus such as beakers, flasks, or other containers; heating furnaces can be used for the phosphating reaction, with common furnaces including but not limited to resistance furnaces, microwave furnaces, induction furnaces, and radiation furnaces; the corresponding raw material holding devices or containers or reaction sites are not specifically limited, with common raw material placement devices including but not limited to crucibles, glass, quartz, and other similar vessels; external devices providing the reaction atmosphere can be either existing self-built or commercially available equipment, and are not limited here.

[0033] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0034] Based on the low activity of existing nickel phosphide (Ni2P) catalysts in the electrocatalytic hydrogen evolution process, the inventors of this invention, through extensive experimental research, unexpectedly discovered that by preparing a sheet-like nickel-containing precursor (nickel hydroxide) based on tetrabutylammonium hydroxide and then subjecting it to phosphating, a nickel phosphide (Ni2P) catalyst with a specific morphology can be prepared. This catalyst exhibits excellent hydrogen evolution catalytic activity and can achieve excellent hydrogen production results in the electrocatalytic hydrogen evolution process when used as a water electrolysis catalyst. Further research and analysis led the inventors to believe that the tetrabutylammonium hydroxide used in this invention is responsible for the high ionization rate of OH groups. - When the reaction with the nickel-containing metal salt is controlled within the melt, the tetrabutylammonium hydroxide plays a kinetic role in regulating the nucleation and crystallization process of the inorganic material. In other words, in this invention, the tetrabutylammonium hydroxide exists simultaneously as a solvent and a structure regulator during the reaction process, preparing a small-sized, sheet-like, low-crystallinity nickel-containing precursor (nickel hydroxide). Then, phosphating is performed to maximize the preservation of the morphology and structure of the nickel-containing precursor (nickel hydroxide), ultimately obtaining a small-sized, sheet-like, low-crystallinity nickel phosphide (Ni2P) catalyst.

[0035] Furthermore, the preparation method of this invention is simple and easy to scale up, and has potential application value in the field of hydrogen production by electrolysis of water based on nickel phosphide (Ni2P) as a catalyst. Attached Figure Description

[0036] Figure 1 This is a transmission electron microscope image of the sheet-like nickel hydroxide prepared in Example 1 of the present invention;

[0037] Figure 2This is a transmission electron microscope image of the nickel phosphide catalyst prepared in Example 1 of the present invention;

[0038] Figure 3 The X-ray powder diffraction pattern of the nickel phosphide catalyst prepared in Example 1 of this invention;

[0039] Figure 4 The polarization curves are for hydrogen evolution catalyzed by the nickel phosphide catalyst prepared in Example 1 of this invention. Detailed Implementation

[0040] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0041] Unless otherwise specified in the following examples, all raw materials are commercially available or prepared by conventional methods in the art.

[0042] Example 1:

[0043] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0044] Preparation methods include:

[0045] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0046] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0047] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0048] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0049] Preparation of nickel phosphide (Ni2P) catalyst:

[0050] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0051] Example 2:

[0052] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0053] Preparation methods include:

[0054] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0055] Preparation of aqueous solution of nickel metal salt: Dissolve 0.1 g of nickel acetate in 1 L of water;

[0056] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0057] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0058] Preparation of nickel phosphide (Ni2P) catalyst:

[0059] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0060] Example 3:

[0061] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0062] Preparation methods include:

[0063] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0064] Preparation of aqueous solution of nickel metal salt: Dissolve 0.8 g of nickel acetate in 1 L of water;

[0065] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0066] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0067] Preparation of nickel phosphide (Ni2P) catalyst:

[0068] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0069] Example 4:

[0070] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0071] Preparation methods include:

[0072] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0073] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 0.5L of water;

[0074] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0075] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0076] Preparation of nickel phosphide (Ni2P) catalyst:

[0077] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0078] Example 5:

[0079] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0080] Preparation methods include:

[0081] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0082] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 3L of water;

[0083] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0084] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0085] Preparation of nickel phosphide (Ni2P) catalyst:

[0086] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0087] Example 6:

[0088] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0089] Preparation methods include:

[0090] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0091] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0092] Preparation of tetrabutylammonium hydroxide melt: Place 0.5g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0093] Inject 0.2 mL of nickel metal salt aqueous solution into 0.5 g of tetrabutylammonium hydroxide melt, heat in an oil bath at 100 °C, and stir magnetically for 2 hours. After the reaction is complete, wash the product 5 times with ethanol, and then place it in a vacuum drying oven (drying temperature is about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0094] Preparation of nickel phosphide (Ni2P) catalyst:

[0095] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0096] Example 7:

[0097] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0098] Preparation methods include:

[0099] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0100] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0101] Preparation of tetrabutylammonium hydroxide melt: Place 2g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0102] 0.2 mL of nickel metal salt aqueous solution was injected into 2 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0103] Preparation of nickel phosphide (Ni2P) catalyst:

[0104] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0105] Example 8:

[0106] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0107] Preparation methods include:

[0108] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0109] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0110] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0111] Take 0.5 mL of nickel metal salt aqueous solution and inject it into 1 g of tetrabutylammonium hydroxide melt. Heat in an oil bath at 100 °C and stir magnetically for 2 hours. After the reaction is complete, wash the product with ethanol 5 times and then place it in a vacuum drying oven (drying temperature is about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0112] Preparation of nickel phosphide (Ni2P) catalyst:

[0113] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0114] Example 9:

[0115] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0116] Preparation methods include:

[0117] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0118] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0119] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0120] 0.05 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0121] Preparation of nickel phosphide (Ni2P) catalyst:

[0122] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0123] Example 10:

[0124] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0125] Preparation methods include:

[0126] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0127] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0128] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0129] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0130] Preparation of nickel phosphide (Ni2P) catalyst:

[0131] Under argon gas protection, 0.25 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0132] Example 11:

[0133] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0134] Preparation methods include:

[0135] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0136] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0137] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0138] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0139] Preparation of nickel phosphide (Ni2P) catalyst:

[0140] Under argon gas protection, 1.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0141] Example 12:

[0142] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0143] Preparation methods include:

[0144] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0145] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0146] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0147] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0148] Preparation of nickel phosphide (Ni2P) catalyst:

[0149] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 10 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0150] Example 13:

[0151] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0152] Preparation methods include:

[0153] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0154] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0155] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0156] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0157] Preparation of nickel phosphide (Ni2P) catalyst:

[0158] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 200 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0159] Example 14:

[0160] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0161] Preparation methods include:

[0162] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0163] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0164] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0165] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0166] Preparation of nickel phosphide (Ni2P) catalyst:

[0167] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 280 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0168] Example 15:

[0169] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0170] Preparation methods include:

[0171] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0172] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0173] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0174] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0175] Preparation of nickel phosphide (Ni2P) catalyst:

[0176] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 330 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0177] Example 16:

[0178] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0179] Preparation methods include:

[0180] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0181] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0182] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0183] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0184] Preparation of nickel phosphide (Ni2P) catalyst:

[0185] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 1.5 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0186] Example 17:

[0187] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0188] Preparation methods include:

[0189] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0190] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0191] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0192] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0193] Preparation of nickel phosphide (Ni2P) catalyst:

[0194] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2.5 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0195] Example 18:

[0196] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0197] Preparation methods include:

[0198] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0199] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel nitrate in 1L of water;

[0200] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0201] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0202] Preparation of nickel phosphide (Ni2P) catalyst:

[0203] Under argon gas protection, 0.5 g of sodium dihydrogen phosphate was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0204] Example 19:

[0205] This example provides a method for preparing nickel phosphide (Ni2P) catalyst and the preparation of the prepared nickel phosphide (Ni2P) catalyst.

[0206] Preparation methods include:

[0207] Preparation of flake nickel hydroxide (i.e., flake nickel-containing precursor):

[0208] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0209] Preparation of tetrabutylammonium hydroxide melt: Place 1g of tetrabutylammonium hydroxide in a beaker, heat in an oil bath at 100℃, and stir magnetically to melt the tetrabutylammonium hydroxide into a liquid.

[0210] 0.2 mL of nickel metal salt aqueous solution was injected into 1 g of tetrabutylammonium hydroxide melt, heated in an oil bath at 100 °C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed 5 times with ethanol and then placed in a vacuum drying oven (drying temperature about 60 °C) for 12 hours to obtain flake nickel hydroxide.

[0211] Preparation of nickel phosphide (Ni2P) catalyst:

[0212] Under argon gas protection, 0.2 g of white phosphorus was placed upstream of the argon gas flow, and 50 mg of flake nickel hydroxide was placed downstream of the argon gas flow. The tube furnace was heated from room temperature to 300 °C and held at this temperature for 2 hours. After the reaction, the product was washed twice with water and ethanol, respectively, and then vacuum dried (at a drying temperature of approximately 60 °C) for 12 hours to obtain nickel phosphide (Ni2P) catalyst.

[0213] Comparative Example 1:

[0214] Preparation of aqueous solution of nickel metal salt: Dissolve 0.3g of nickel acetate in 1L of water;

[0215] Preparation of tetrabutylammonium hydroxide aqueous solution: Dissolve 1g of tetrabutylammonium hydroxide in 1L of water;

[0216] The aqueous solution of nickel metal salt was mixed with the aqueous solution of tetrabutylammonium hydroxide, heated in an oil bath at 100°C, and magnetically stirred for 2 hours. After the reaction was completed, the product was washed and dried. The resulting product did not show the morphology of the sheet-like structure of the present invention.

[0217] Performance testing

[0218] (1) The flake-shaped nickel hydroxide prepared in Example 1 of this invention was characterized by transmission electron microscopy to obtain... Figure 1 The transmission electron microscope image shown shows that the nickel hydroxide produced in this invention has a sheet-like structure.

[0219] (2) The nickel phosphide catalyst prepared in Example 1 of this invention was characterized by transmission electron microscopy to obtain... Figure 2 The transmission electron microscope image shown shows that the nickel phosphide catalyst prepared in this invention maintains the sheet-like structure of sheet-like nickel hydroxide (i.e., sheet-like nickel-containing precursor).

[0220] (3) The nickel phosphide catalyst prepared in Example 1 of this invention was characterized by X-ray powder diffraction to obtain... Figure 3 The X-ray powder diffraction pattern shown illustrates, on the one hand, the formation of the crystalline nickel phosphide (Ni2P) of this invention, consistent with standard JCPDS card No. 03-0953; on the other hand, it can be seen from the pattern that the signal peak is very weak, almost the same as the noise peak, indicating that the nickel phosphide (Ni2P) catalyst prepared by this invention has low crystallinity.

[0221] (4) The hydrogen evolution performance of the nickel phosphide (Ni2P) catalyst prepared in the embodiments of the present invention was tested by electrolysis of water. The specific test process was as follows: 5 mg of the nickel phosphide catalyst prepared in Example 1 of the present invention was dispersed in a mixed solvent consisting of 900 μL of water and 100 μL of Nafion solution (commercially available product, also known as perfluorosulfonic acid polymer solution, with a mass concentration of 5%), and ultrasonicated for 30 minutes to form a uniform dispersion. 5 μL of the dispersion was dropped onto a 3 mm diameter glassy carbon electrode, dried under vacuum at room temperature, and then used as the working electrode for electrochemical characterization. A 1 mol / L potassium hydroxide aqueous solution was used as the electrolyte, a saturated calomel electrode was used as the reference electrode, and a stone rod was used as the counter electrode. The scanning rate was 5 mV·s during polarization curve scanning. -1 The recorded polarization potentials have been converted to potentials relative to the reversible hydrogen electrode (RHE). The polarization curves for the catalytic hydrogen evolution of the nickel phosphide (Ni2P) catalyst prepared in Example 1 are shown below. Figure 4 As shown, at a current density of 10 mA·cm -2 At that time, overpotential (η) 10 The voltage is 119mV, even if the current density increases to 20mA·cm. -2 At that time, overpotential (η) 10 The overpotential is only 181 mV, which shows that the nickel phosphide (Ni2P) catalyst prepared by the method of the present invention greatly reduces the overpotential and significantly improves the hydrogen evolution catalytic activity.

[0222] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0223] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. Use of phosphorus nickel dide in the process of hydrogen production by electrolysis of water, characterized in that, The X-ray powder diffraction peak of the phosphorus nickel is consistent with JCPDS card No. 03-0953, and the phosphorus nickel is in a sheet structure; The method for preparing the phosphorus nickel comprises: (1) preparation of a sheet-shaped nickel-containing precursor dissolving a nickel metal salt in water to prepare a nickel metal salt aqueous solution; heating tetrabutylammonium hydroxide to melting to obtain a tetrabutylammonium hydroxide melt; injecting the aqueous nickel metal salt solution into the tetrabutylammonium hydroxide melt at a preset ratio, and reacting under heating to generate a flaky nickel-containing precursor; wherein the preset ratio is to control the average content of the nickel metal salt in the tetrabutylammonium hydroxide melt to be 4.5×10 -9 ~1.5×10 -3 mol per gram of the tetrabutylammonium hydroxide melt, and the ratio of the volume of the aqueous nickel metal salt solution to the mass of the tetrabutylammonium hydroxide melt is 0.025-0.8 mL / g. (2) preparation of the phosphorus nickel under the protection of a protective atmosphere, placing a phosphorus source upstream of a protective gas flow, placing the sheet-shaped nickel-containing precursor downstream of the protective gas flow, heating to a preset reaction temperature, and keeping warm to react to generate the phosphorus nickel.

2. The use of phosphorus nickel according to claim 1 in the process of hydrogen production by electrolysis of water, characterized by, In step (2), the protective gas is nitrogen or an inert gas; and / or, the ratio of the addition molar amount of the phosphorus source to the feeding molar amount of the sheet-shaped nickel-containing precursor is 2.1-60:

1.

3. The use of phosphorus nickel according to claim 1 in the process of hydrogen production by electrolysis of water, characterized by, In step (2), after the end of the keeping warm reaction, washing and vacuum drying are performed; The washing is performed using water and an alcohol solvent respectively, and the temperature of the vacuum drying is 20-80°C.

4. The use of phosphorus nickel according to claim 1 in the process of hydrogen production by electrolysis of water, characterized by, In step (2), the preset reaction temperature is controlled to be 280-330°C; and / or, the keeping warm time of the keeping warm reaction is controlled to be 1-4h.

5. The use of phosphorus nickel according to claim 1 in the process of hydrogen production by electrolysis of water, characterized by, In step (2), the phosphorus source is a combination of one or more selected from hypophosphite, phosphate, white phosphorus and red phosphorus, the hypophosphite is sodium hypophosphite and / or potassium hypophosphite, and the phosphate is sodium phosphate and / or potassium phosphate.

6. The use of phosphorus nickel according to claim 1 in the process of hydrogen production by electrolysis of water, characterized by, In step (1), the nickel metal salt is a combination of one or more selected from nickel acetate, nickel nitrate, nickel chloride and nickel sulfate, and the mass concentration of the nickel metal salt in the nickel metal salt aqueous solution is 0.02-2.0g / L.

7. The use of phosphorus nickel according to claim 1 in the process of hydrogen production by electrolysis of water, characterized by, In step (1), the heating temperature of the heating condition is controlled to be 80-120°C.

8. The use of phosphorus nickel according to claim 1 in the process of hydrogen production by electrolysis of water, characterized by, In step (1), the ratio of the volume of the nickel metal salt aqueous solution to the mass of the tetrabutylammonium hydroxide melt is 0.04-0.6 mL / g.

9. The use of phosphorus nickel according to claim 1 in the process of hydrogen production by electrolysis of water, characterized by, The thickness of the phosphorus nickel in the sheet structure is 1-5nm, and the two-dimensional plane size is 5-20nm.

10. The use of phosphorus dichromium according to claim 1 in the process of hydrogen production by electrolysis of water, characterized by the fact that, The application comprises: in an acidic electrolyte, an alkaline electrolyte or a neutral electrolyte, using the phosphorus nickel as an electrolytic water catalyst to electrolyze water to produce hydrogen.

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