Preparation method of nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater and product

Abstract

The invention discloses a preparation method of a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater and a product. The preparation method comprises the steps of surface treatment of a nickel-iron alloy sheet and preparation of a boronized nickel-iron alloy sheet composite electrode. According to the method, the marketed NiFe alloy sheet is directly subjected to thermal boronizing treatment and is directly subjected to electrochemical oxidation to prepare the multi-chromatography oxygen electrode, and various requirements of an anode material for seawater decomposition can be met. The prepared multi-layer oxygen electrode is mainly composed of a surface oxide layer, an alloy middle layer and an alloy substrate layer. The NiFeB alloy layer on the surface plays a role of a catalytic active layer, the NiFeB alloy layer in the middle plays a role of a corrosion-resistant layer, the NiFe alloy layer on the substrate plays a role of supporting, and the electrode material is efficiently supported by multiple layers together, so that the electrode material has a rapid electron transfer process, and the electrode material can show relatively high catalytic activity. The electrode material is cheap in raw material source and simple in preparation process, and has a relatively strong commercial application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of electrocatalytic hydrogen production, and relates to a preparation method and product of a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater. Specifically, a preparation method of a molybdenum carbide-loaded carbon cloth fiber composite electrode for electrocatalytic decomposition of water to produce hydrogen is disclosed. Background Art

[0002] Water electrolysis has always been considered a clean and sustainable method of hydrogen production. However, due to the scarcity of fresh water resources, the direct electrolysis of seawater to produce hydrogen has become an important direction for the future development of hydrogen energy. Due to the complex composition of seawater, it is more corrosive than fresh water, especially due to the presence of Cl in seawater. - At high concentrations, a chloride ion oxidation reaction (ClOR) will occur during the electrolysis of water. The hypochlorite produced will severely inhibit the oxygen evolution reaction (OER) at the anode and corrode the electrode, thereby reducing the efficiency of seawater electrolysis. The OER reaction involves a multi-electron transfer process, which is slower than the hydrogen evolution reaction (HER) kinetics and is a key factor restricting the efficiency of the entire seawater electrolysis device. Seawater mainly contains Cl − (~0.55 M), Na + (~0.48 M), Mg 2+ In the presence of a 0.05 M plasma, the chlorine evolution reaction (ClOR) at the anode can compete with the oxygen evolution reaction (OER) due to its similar thermodynamics. Therefore, efforts have been devoted to developing methods to improve the OER performance and suppress ClOR.

[0003] ClO − As an oxidation product of ClOR under alkaline conditions, it will cause serious corrosion problems to the entire electrolysis device. Current research shows that increasing pH value will inhibit ClOR, so alkaline conditions are conducive to Ca 2+ and Mg 2+ Alkaline electrolysis is considered to be the most promising water electrolysis technology for large-scale hydrogen production. Current research focuses on building a protective layer on the anode to achieve Cl − Separation from the catalyst inhibits the corrosion and side reactions mentioned above. However, due to the harsh environment of seawater, the modified protective layer of the electrode is usually not stable enough, and this inhibition strategy faces the problem of unsatisfactory durability. Nickel electrodes are often used as commercial electrocatalytic alkaline oxygen evolution electrodes due to their excellent conductivity and moderate stability, but their catalytic activity is not high. Therefore, the development of a high-performance alkaline seawater decomposition catalyst material is extremely critical.

[0004] This invention provides a method for preparing a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater. This patented invention utilizes commercially available NiFe alloy sheets through direct thermal boronization followed by electrochemical oxidation to produce a multi-layer oxygen evolution electrode that meets the diverse requirements of anode materials for seawater decomposition. The electrode primarily consists of a surface-oxidized NiFeB alloy layer, a corrosion-resistant NiFeB alloy intermediate layer, and a supporting NiFe alloy substrate. This method utilizes inexpensive raw materials, has a simple preparation process, and possesses strong application prospects. Summary of the Invention

[0005] The present invention aims to provide a method for preparing a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater.

[0006] Another object of the present invention is to provide a nickel-iron alloy composite electrode product suitable for alkaline seawater electrocatalytic cracking prepared according to the above method.

[0007] The object of the present invention is achieved through the following solutions: A method for preparing a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater, comprising the following steps: The first step is surface treatment of the nickel-iron alloy sheet: soak the commercially available NiFe alloy sheet in acetone to remove surface oil; then use 200-grit sandpaper to further remove adsorbents to keep the surface of the NiFe sheet clean, wash it three times with deionized water, and dry it; The second step is the preparation of the boronized nickel-iron alloy composite electrode: a certain amount of boron powder is placed in a tube furnace, and a NiFe sheet with a clean surface is inserted into the boron powder to ensure that the NiFe sheet is completely buried in the boron powder; the NiFe sheet is heated at 3°C ​​min-1 under a protective gas Ar atmosphere. -1 The temperature was raised to a specific temperature at a heating rate of , and the temperature was kept constant for 1 hour; when the temperature of the tube furnace dropped to room temperature, the sample was taken out, washed three times with ethanol, and dried to obtain a boronized nickel-iron alloy composite electrode.

[0008] In the preparation process of the boronized nickel-iron alloy sheet composite electrode, the NiFe sheet used is of a size of 10.0 cm (length) * 5.0 cm (width) * 0.5 cm (thickness); During the preparation of the boronized nickel-iron alloy sheet composite electrode, the boron powder used is an excess of commercial boron powder, which can completely embed the nickel-iron alloy sheet; The calcination temperature in the tubular furnace is controlled in the range of 850-1000°C, preferably 950°C.

[0009] The present invention provides a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater, characterized by being prepared according to any of the aforementioned methods. The electrode primarily comprises a three-layer structure, comprising a NiFe alloy substrate, an oxidized NiFeB alloy layer on the surface, and a NiFeB alloy intermediate layer in the middle. The oxidized NiFeB alloy layer on the surface serves as a catalytically active layer, the NiFeB alloy intermediate layer serves as a corrosion-resistant layer, and the NiFe alloy substrate provides support. This multi-layer oxygen evolution electrode exhibits excellent catalytic activity, water decomposition stability, and resistance to chloride ion corrosion in chloride-containing electrolytes.

[0010] Compared with the existing technology, the technical feature of the present invention is that seawater is more corrosive than fresh water, especially Cl in seawater. - To address the technical challenge of hypochlorite generation and electrode corrosion at high concentrations, the present invention has developed a multi-layer oxygen evolution electrode for seawater decomposition. This composite electrode, consisting of a surface-oxidized NiFeB alloy layer as a catalytically active layer, a NiFe alloy intermediate layer as a corrosion-resistant layer, and a NiFe alloy substrate as a supporting structure, exhibits excellent catalytic activity and high corrosion resistance to chlorides. This method utilizes commercially available NiFe alloy sheets to produce electrolytic materials, offering a wide range of sources, a simple preparation method, and strong application prospects.

[0011] Activity test of electrocatalytic oxygen evolution catalyst: The electrocatalytic oxygen evolution catalytic activity test was conducted using a CHI-660E three-electrode electrochemical workstation. The reference electrode was a saturated calomel electrode, the carbon rod electrode was a platinum wire, and the prepared nickel-iron boride alloy sheet was used as the working electrode. The electrochemical cell was a plastic centrifuge tube with a diameter of 4 cm and a height of 8 cm. The electrolyte used for the test was a 30 wt% KOH + 0.5 M NaCl solution. The actual working area of ​​the working electrode was 0.2 cm. 2 The remaining portion was covered with hot melt. The experimentally measured potential conversion relationship between the potential relative to a saturated calomel electrode and the potential relative to a reversible hydrogen electrode was E (vs. RHE) = E (vs. Hg / HgO) + 0.924 V. The voltage sweep rate was 1–50 mV / s.

[0012] This invention directly thermally borides commercially available NiFe alloy sheets and then electrochemically oxidizes them to produce a multilayer oxygen-evolution electrode, which can meet the diverse needs of anode materials for seawater decomposition. The prepared multilayer oxygen-evolution electrode primarily consists of a surface oxide layer, an alloy intermediate layer, and an alloy base layer. The surface NiFeB alloy layer serves as a catalytically active layer, the intermediate NiFeB alloy layer acts as a corrosion-resistant layer, and the base NiFe alloy layer provides support. These multiple layers efficiently support the electrode material, resulting in rapid electron transfer and high catalytic activity. This electrode material is inexpensive in raw materials, simple to prepare, and has strong commercial application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the linear sweep voltammetry (LSV) spectrum of the nickel-iron alloy composite electrode suitable for alkaline seawater electrocatalytic cracking. DETAILED DESCRIPTION

[0014] This embodiment is implemented on the premise of the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiment.

[0015] Example 1 A nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater is prepared according to the following steps: The first step is surface treatment of the nickel-iron alloy sheet: commercially available NiFe alloy sheets are cut into pieces of 10.0 cm (length) * 5.0 cm (width) * 0.5 cm (thickness) and soaked in acetone to remove surface oil stains. The sheets are then polished with 200-grit sandpaper to further remove adsorbents and keep the surface of the NiFe sheet clean. The sheets are then washed three times with deionized water and air-dried. The second step is the preparation of the boronized nickel-iron alloy composite electrode: 20g of boron powder is placed in a tube furnace, and a NiFe sheet with a clean surface is inserted into the boron powder to ensure that the NiFe sheet is completely buried in the boron powder; the NiFe sheet is heated at 3℃min under a protective gas Ar atmosphere. -1 The temperature was raised to 950 °C at a heating rate of 100 °C, kept at a constant temperature for 1 hour, and then cooled down; when the temperature of the tube furnace dropped to room temperature, the sample was taken out, washed three times with ethanol, and dried to obtain a boronized nickel-iron alloy composite electrode.

[0016] like Figure 1 As shown in the figure, in 1 M KOH electrolyte, at the same current density, the overpotential of the nickel-iron boride alloy sheet is significantly smaller than that of the nickel-iron alloy sheet; since the current density is normalized by the electrode geometric area, it shows that the nickel-iron boride alloy sheet has a higher apparent electrocatalytic activity.

[0017] Example 2 A nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater is prepared according to the following steps: The first step is surface treatment of the nickel-iron alloy sheet: commercially available NiFe alloy sheets are cut into pieces of 10.0 cm (length) * 5.0 cm (width) * 0.5 cm (thickness) and soaked in acetone to remove surface oil stains. The sheets are then polished with 200-grit sandpaper to further remove adsorbents and keep the surface of the NiFe sheet clean. The sheets are then washed three times with deionized water and air-dried. The second step is the preparation of the boronized nickel-iron alloy composite electrode: 20 g of boron powder is placed in a tube furnace, and a NiFe sheet with a clean surface is inserted into the boron powder to ensure that the NiFe sheet is completely buried in the boron powder; the NiFe sheet is heated at 3 °C min under a protective gas Ar atmosphere. -1 The temperature was raised to 1050 °C at a heating rate of 1000 °C, kept at a constant temperature for 1 hour, and then cooled down; when the temperature of the tube furnace dropped to room temperature, the sample was taken out, washed three times with ethanol, and dried to obtain a boronized nickel-iron alloy composite electrode.

[0018] Example 3 A nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater is prepared according to the following steps: The first step is surface treatment of the nickel-iron alloy sheet: commercially available NiFe alloy sheets are cut into pieces of 10.0 cm (length) * 5.0 cm (width) * 0.5 cm (thickness) and soaked in acetone to remove surface oil stains. The sheets are then polished with 200-grit sandpaper to further remove adsorbents and keep the surface of the NiFe sheet clean. The sheets are then washed three times with deionized water and air-dried. The second step is the preparation of the boronized nickel-iron alloy composite electrode: 20 g of boron powder is placed in a tube furnace, and a NiFe sheet with a clean surface is inserted into the boron powder to ensure that the NiFe sheet is completely buried in the boron powder; the NiFe sheet is heated at 3 °C min under a protective gas Ar atmosphere. -1 The temperature was raised to 850 °C at a heating rate of 100 °C, kept at a constant temperature for 1 hour, and then cooled down; when the temperature of the tube furnace dropped to room temperature, the sample was taken out, washed three times with ethanol, and dried to obtain a boronized nickel-iron alloy composite electrode.

[0019] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater, characterized in that Here are the steps: The first step is surface treatment of the nickel-iron alloy sheet: soak the commercially available NiFe alloy sheet in acetone to remove surface oil; then use 200-grit sandpaper to further remove adsorbents to keep the surface of the NiFe sheet clean, wash it three times with deionized water, and dry it; The second step is the preparation of the boronized nickel-iron alloy composite electrode: a certain amount of boron powder is placed in a tube furnace, and a NiFe sheet with a clean surface is inserted into the boron powder to ensure that the NiFe sheet is completely buried in the boron powder; the NiFe sheet is heated at 3°C ​​min-1 under a protective gas Ar atmosphere. -1 The temperature was raised to a specific temperature at a heating rate of , and the temperature was kept constant for 1 hour; when the temperature of the tube furnace dropped to room temperature, the sample was taken out, washed three times with ethanol, and dried to obtain a boronized nickel-iron alloy composite electrode.

2. The method for preparing a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater according to claim 1, characterized in that: In the preparation process of the boronized nickel-iron alloy sheet composite electrode, the NiFe sheet used has a specification of 10.0 cm (length) * 5.0 cm (width) * 0.5 cm (thickness).

3. The method for preparing a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater according to claim 1, characterized in that: During the preparation of the boronized nickel-iron alloy sheet composite electrode, the boron powder used is an excess of commercial boron powder, which can completely embed the nickel-iron alloy sheet.

4. The method for preparing a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater according to claim 1, characterized in that: The calcination temperature of the tubular furnace is controlled at 850-1000°C.

5. The method for preparing a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater according to any one of claims 1 to 4, characterized in that: Prepare as follows: The first step is surface treatment of the nickel-iron alloy sheet: commercially available NiFe alloy sheets are cut into pieces of 10.0 cm (length) * 5.0 cm (width) * 0.5 cm (thickness) and soaked in acetone to remove surface oil stains. The sheets are then polished with 200-grit sandpaper to further remove adsorbents and keep the surface of the NiFe sheet clean. The sheets are then washed three times with deionized water and air-dried. The second step is the preparation of the boronized nickel-iron alloy composite electrode: 20 g of boron powder is placed in a tube furnace, and a NiFe sheet with a clean surface is inserted into the boron powder to ensure that the NiFe sheet is completely buried in the boron powder; the NiFe sheet is heated at 3 °C min under a protective gas Ar atmosphere. -1 The temperature was raised to 950 °C at a heating rate of 100 °C, kept at a constant temperature for 1 hour, and then cooled down; when the temperature of the tube furnace dropped to room temperature, the sample was taken out, washed three times with ethanol, and dried to obtain a boronized nickel-iron alloy composite electrode.

6. The method for preparing a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater according to any one of claims 1 to 4, characterized in that: Prepare as follows: The first step is surface treatment of the nickel-iron alloy sheet: commercially available NiFe alloy sheets are cut into pieces of 10.0 cm (length) * 5.0 cm (width) * 0.5 cm (thickness) and soaked in acetone to remove surface oil stains. The sheets are then polished with 200-grit sandpaper to further remove adsorbents and keep the surface of the NiFe sheet clean. The sheets are then washed three times with deionized water and air-dried. The second step is the preparation of the boronized nickel-iron alloy composite electrode: 20 g of boron powder is placed in a tube furnace, and a NiFe sheet with a clean surface is inserted into the boron powder to ensure that the NiFe sheet is completely buried in the boron powder; the NiFe sheet is heated at 3 °C min under a protective gas Ar atmosphere. -1 The temperature was raised to 1050 °C at a heating rate of 1000 °C, kept at a constant temperature for 1 hour, and then cooled down; when the temperature of the tube furnace dropped to room temperature, the sample was taken out, washed three times with ethanol, and dried to obtain a boronized nickel-iron alloy composite electrode.

7. The method for preparing a nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater according to any one of claims 1 to 4, characterized in that: Prepare as follows: The first step is surface treatment of the nickel-iron alloy sheet: commercially available NiFe alloy sheets are cut into pieces of 10.0 cm (length) * 5.0 cm (width) * 0.5 cm (thickness) and soaked in acetone to remove surface oil stains. The sheets are then polished with 200-grit sandpaper to further remove adsorbents and keep the surface of the NiFe sheet clean. The sheets are then washed three times with deionized water and air-dried. The second step is the preparation of the boronized nickel-iron alloy composite electrode: 20 g of boron powder is placed in a tube furnace, and a NiFe sheet with a clean surface is inserted into the boron powder to ensure that the NiFe sheet is completely buried in the boron powder; the NiFe sheet is heated at 3 °C min under a protective gas Ar atmosphere. -1 The temperature was raised to 850 °C at a heating rate of 100 °C, kept at a constant temperature for 1 hour, and then cooled down; when the temperature of the tube furnace dropped to room temperature, the sample was taken out, washed three times with ethanol, and dried to obtain a boronized nickel-iron alloy composite electrode.

8. A nickel-iron alloy composite electrode suitable for electrocatalytic cracking of alkaline seawater, characterized in that Prepared according to the method described in any one of claims 1 to 7; the electrode mainly has a three-layer structure, the substrate is NiFe alloy, the surface is an oxidized NiFeB alloy layer, and the middle is a NiFeB alloy intermediate layer; the surface oxidized NiFeB alloy layer acts as a catalytic active layer, the NiFeB alloy intermediate layer serves as a corrosion-resistant layer, and the substrate is NiFe alloy that plays a supporting role.

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