Preparation method of iron phosphide nanowire array used as hydrogen evolution reaction electrocatalyst

Abstract

The invention relates to a preparation method of an iron phosphide nanowire array, which comprises the following steps: (1) sequentially carrying out ultrasonic treatment on carbon cloth for 15 minutes by using acetone, deionized water and absolute ethyl alcohol, loading a precursor FeOOH of iron phosphide onto the treated carbon cloth by using ferric nitrate and sodium sulfate as raw materials through a hydrothermal method, and drying in a drying box; (2) putting the dried sample into the downstream of a closed tubular furnace, putting 1g of sodium hypophosphite into the upstream of the tubular furnace, heating to 350 DEG C at a heating rate of 5 DEG C / min, preserving heat for 2 hours, and naturally cooling; and washing the obtained sample with pure water and alcohol for several times, and drying in a drying box for 2 hours to obtain the iron phosphide nanowire array. The preparation method is simple, the raw materials are easy to obtain, the experimental temperature is low, and the prepared iron phosphide nanowire array can effectively reduce the overpotential of an electro-catalytic hydrogen evolution reaction and is good in catalytic performance.

Description

Technical Field

[0001] The patent of this invention relates to the technical field of preparation of iron phosphide nanowire arrays, and specifically to a method for preparing an iron phosphide nanowire array as a hydrogen evolution electrocatalyst. Background Art

[0002] At present, fossil fuels are still the main energy source that cannot be replaced. However, the sustainable use of fossil fuels is worrying. With the change of development needs, the development concept has changed from economic priority to harmonious coexistence between man and nature, and the environmental problems caused by fossil energy have to be taken seriously. Therefore, finding a sustainable and environmentally friendly energy has become a new direction for the development of human society.

[0003] Hydrogen has received widespread attention due to its high energy density and pollution-free combustion. At present, hydrogen is mainly prepared by the following means: pyrolysis of water, electrolysis of water, and steam reforming. Among them, the pyrolysis of water is inefficient and consumes a large amount of fossil energy, and the steam reforming method produces carbon monoxide during the production of hydrogen. The electrolysis of water is simple to operate, and no harmful by-products are generated during the reaction process. Although this method also has the problem of high hydrolysis overpotential, the overpotential can be reduced and the reaction process can be accelerated by using a catalyst.

[0004] At present, the electrocatalytic materials with the best catalytic activity are still precious metals such as platinum, ruthenium, and rhodium. However, due to the scarcity and high price of precious metal resources, the cost of electrocatalysis is too high, making the industrialization of hydrogen production impossible. The research and development of low-cost electrocatalysts has become a key link in the large-scale production of hydrogen. After years of exploration, iron has gradually entered the field of vision of researchers. Iron-doped, multi-phase iron-based composite materials show efficient catalytic activity. Summary of the invention

[0005] The purpose of the present invention is to provide a method for preparing an iron phosphide nanowire array electrocatalytic material and its application. The present invention adopts a hydrothermal method and a thermal phosphating method, and uses a carbon cloth as a substrate to grow an iron phosphide nanowire array with high catalytic activity. The iron phosphide nanowire array can effectively reduce the overpotential of the electrocatalytic hydrogen evolution reaction and improve the efficiency of hydrogen production by electrolysis of water. At the same time, the production process of the material is simple, the required raw materials are much cheaper than precious metals, the preparation process is safe and reliable, and it is expected to become a substitute for precious metal catalysts.

[0006] The technical solution adopted by the present invention is:

[0007] (1) The carbon cloth was first ultrasonically cleaned with acetone, deionized water, and ethanol for 15 minutes in sequence; 1.414 g of ferric nitrate and 0.497 g of sodium sulfate were dissolved in 80 ml of deionized water to form an opaque dark red solution, which was poured into a 100 ml Teflon liner. The treated carbon cloth was then placed in the solution at an angle along the inner wall, and the lid was tightly closed and placed in a hydrothermal autoclave.

[0008] (2) placing the hydrothermal autoclave in a hydrothermal box at 120°C for 6 hours, and taking it out after natural cooling; taking out the prepared carbon cloth material with tweezers, washing it with deionized water and ethanol three times in sequence, and then placing it in an oven at 60°C to dry, thereby obtaining FeOOH / CC.

[0009] (3) Place the carbon cloth material dried in step (2) in a tube furnace for vacuum packaging, place 1g of sodium hypophosphite in the upstream of the tube furnace, and place the dried carbon cloth material in the downstream, heat it to 350°C at a rate of 5°C / min and keep it for 2 hours, then take it out after natural cooling. Rinse it with deionized water and anhydrous ethanol several times and place it in an oven at 60°C to dry, and then you can get the iron phosphide nanowire array

[0010] Preferably, the hydrothermal temperature is 120°C.

[0011] Preferably, the hydrothermal insulation time is 6 hours.

[0012] Preferably, the precursor is FeOOH / CC.

[0013] Preferably, the amount of the sodium hypophosphite is 1 g.

[0014] Preferably, the phosphating temperature is 350°C.

[0015] Preferably, the phosphating heating rate is 5°C / min.

[0016] Preferably, the phosphating time is 2 hours.

[0017] Preferably, the room temperature is 15-35°C.

[0018] Beneficial effects of the present invention:

[0019] The raw materials required by the invention are easy to obtain, and the preparation conditions are simple and easy. The heating rate and the insulation temperature selected in the thermal phosphating process are consistent with the amount of sodium hypophosphite, ensuring that the reaction is carried out in a safe and reliable pressure range and temperature range. The prepared iron phosphide nanowire array has good crystallinity, can effectively catalyze the reaction as a catalyst for the electrocatalytic hydrogen evolution reaction, and has the technical prerequisite for large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a preparation flow chart of iron phosphide nanowire array materials, a preparation flow chart of iron phosphide.

[0021] Figure 2 This is the XRD pattern of iron phosphide nanowire array material, XRD of iron phosphide.

[0022] Figure 3 This is the SEM image of iron phosphide nanowire array material (magnified 5000 times), SEM of iron phosphide (magnified 5000 times).

[0023] Figure 4 LSV diagram of iron phosphide nanowire array material, LSV performance curve of iron phosphide. DETAILED DESCRIPTION

[0024] Implementation

[0025] (1) The carbon cloth was first ultrasonically cleaned with acetone, deionized water, and ethanol for 15 minutes in sequence; 1.414 g of ferric nitrate and 0.497 g of sodium sulfate were dissolved in 80 ml of deionized water to form an opaque dark red solution, which was poured into a 100 ml Teflon liner. The treated carbon cloth was then placed in the solution at an angle along the inner wall, and the lid was tightly closed and placed in a hydrothermal autoclave.

[0026] (2) placing the hydrothermal autoclave in a hydrothermal box at 120°C for 6 hours, and taking it out after natural cooling; taking out the prepared carbon cloth material with tweezers, washing it with deionized water and ethanol three times in sequence, and then placing it in an oven at 60°C to dry, thereby obtaining FeOOH / CC.

[0027] (3) Place the carbon cloth material dried in step (2) in a tube furnace for vacuum packaging, place 1g of sodium hypophosphite in the upstream of the tube furnace, and place the dried carbon cloth material in the downstream, heat it to 350°C at a rate of 5°C / min and keep it for 2 hours, then take it out after natural cooling. Rinse it with deionized water and anhydrous ethanol several times and place it in an oven at 60°C to dry, and then you can get the iron phosphide nanowire array

[0028] Finally, it should be noted that the above embodiments are only used for the technical solutions of the present invention, rather than limiting the present invention. Although the present invention has been described in detail with reference to the above examples, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for the technical features therein, and these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an iron phosphide nanowire array material, characterized in that: The following steps are involved: (1) The carbon cloth was first ultrasonically cleaned with acetone, deionized water, and ethanol for 15 minutes in sequence; 1.414 g of ferric nitrate and 0.497 g of sodium sulfate were dissolved in 80 ml of deionized water to form an opaque dark red solution, which was poured into a 100 ml Teflon liner. The treated carbon cloth was then placed in the solution at an angle along the inner wall, and the lid was tightly closed and placed in a hydrothermal autoclave. (2) The hydrothermal autoclave was placed in a hydrothermal box at 120°C for 6 hours, and then taken out after natural cooling; the prepared carbon cloth material was taken out with tweezers, washed with deionized water and ethanol three times in sequence, and then placed in an oven at 60°C for drying to obtain FeOOH / CC (3) The carbon cloth material dried in the above step (2) is placed in a tube furnace for vacuum packaging, 1 g of sodium hypophosphite is placed in the upstream of the tube furnace, and the dried carbon cloth material is placed in the downstream, and the temperature is raised to 350°C at a rate of 5°C / min and maintained for 2 hours, and then taken out after natural cooling. After being rinsed with deionized water and anhydrous ethanol for multiple times, it is placed in an oven at 60°C for drying to obtain an iron phosphide nanowire array.

2. The method for preparing an iron phosphide nanowire array according to claim 1, characterized in that: The target product can be obtained by using simple raw materials to carry out simple hydrothermal reaction and phosphating reaction at a relatively low temperature.

3. The method for preparing an iron phosphide nanowire array according to claim 1, characterized in that: The iron phosphide nanowire array alkaline electrocatalytic material is used for electrochemical water decomposition, and the performance of electrochemical water decomposition is measured as follows: Electrochemical measurements were performed using an electrochemical analyzer, the instrument model was CHI660E, and the electrolyte used for the measurement was 1M potassium hydroxide solution. The prepared iron phosphide nanowire array was used as the working electrode, the carbon rod was used as the counter electrode, and the saturated calomel electrode (SCE) was used as the reference electrode. Linear voltammetry was used for measurement, with a voltage range of -0.8 to -1.5 V and a scan rate of 5 mV·s -1 .

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