A method for preparing rod-shaped powder electrode material

Abstract

The present invention proposes a method for preparing a rod-shaped powder electrode material, comprising the following steps: S1. Adding a palladium precursor material and a mercury precursor material simultaneously to an organic solvent, then adding a reducing agent, stirring at room temperature, and reacting under high temperature and high pressure; S2. After the reaction is complete, cooling to room temperature, centrifuging the product, washing it, and centrifuging it again to obtain a black substance, and drying the black substance to obtain a black rod-shaped powder electrode material. The present invention successfully introduces the heavy metal element mercury into the palladium-based electrode material, achieving modification of the precious metal palladium and resource utilization of the heavy metal element mercury. The operation is simple and easy to implement. The prepared rod-shaped powder electrode material has potential application value in the field of direct alcohol fuel cells.

Description

Technical Field

[0001] The present invention relates to the technical field of electrode materials for direct alcohol fuel cells, and in particular to a method for preparing a rod-shaped powder electrode material. Background Art

[0002] Direct alcohol fuel cells, as a low-temperature battery system that mainly uses alcohols (methanol, ethanol, ethylene glycol, isopropanol and propylene glycol, etc.) as energy source, have the advantages of being clean and environmentally friendly, having a wide range of material sources, low cost, easy storage and transportation, and high energy conversion efficiency. They are receiving more and more attention and have broad application prospects.

[0003] Direct alcohol fuel cells (DAFCs) consist of an anode, cathode, electrolyte, and external circuit. The anode is the electrode end through which the fuel gas is introduced and fully or partially oxidized. The catalytic properties of the corresponding electrode materials play a crucial role in fuel cells. Commonly used electrode materials include: metals and their oxides (Pt, Pd, Ni, Au, RhO, IrO, etc.); and conductive polymers (polypyrrole, polyaniline, polythiophene, etc.). The precious metal Pt has excellent catalytic properties, and platinum-based materials are the most studied, mature, and widely used electrode materials. However, due to the low reserves and high price of the precious metal Pt, and its easy deactivation, its commercial application is inevitably limited. The research and development of Pt-based alloys or non-Pt materials is an important path to further promote the development of fuel cells. Summary of the Invention

[0004] Based on the technical problems existing in the background technology, the present invention proposes a method for preparing a rod-shaped powder electrode material.

[0005] The present invention provides a method for preparing a rod-shaped powder electrode material, comprising the following steps:

[0006] S1. Adding a palladium precursor material and a mercury precursor material to an organic solvent at the same time, then adding a reducing agent, stirring evenly at room temperature, and reacting under high temperature and high pressure;

[0007] S2. After the reaction is completed, the mixture is cooled to room temperature, the product is centrifuged, washed, and centrifuged again to obtain a black substance, and the black substance is dried to obtain a powder electrode material with a black rod-like morphology.

[0008] In a preferred embodiment of the present invention, in step S1, the palladium precursor material and the mercury precursor material are bistriphenylphosphine palladium dichloride and mercuric iodide, respectively, and the molar ratio of the palladium precursor material to the mercury precursor material is (1:1) to (1:6).

[0009] In a preferred embodiment of the present invention, in step S1, the organic solvent is a mixed solvent of ethylene glycol and N,N-dimethylformamide, and the volume ratio of ethylene glycol to N,N-dimethylformamide is (4:1) to (16:1).

[0010] In a preferred embodiment of the present invention, in step S1, the reducing agent is 2,3,5,6-tetrahydroxy-2-hexene-4-lactone, and 50-150 mg of the reducing agent is added to every 1 L of the mixed solvent.

[0011] In a preferred embodiment of the present invention, in step S1, the reaction is carried out at a high temperature of 120-200° C. for 3-6 hours, and the organic solvent is always in a turbulent state during the reaction.

[0012] In a preferred embodiment of the present invention, in step S2, ethanol solvent and dilute nitric acid are used for washing multiple times.

[0013] In a preferred embodiment of the present invention, in step S2, the volume fraction of the dilute nitric acid is 10% to 30%.

[0014] In a preferred embodiment of the present invention, in step S2, the black substance is dried in a vacuum drying oven for 6 to 12 hours.

[0015] The present invention also provides a rod-shaped powder electrode material prepared by the above method.

[0016] The present invention also proposes an application of the above-mentioned rod-shaped powder electrode material in a direct alcohol fuel cell.

[0017] The precious metal palladium (Pd) is cheaper than the precious metal platinum (Pt), and offers high catalytic activity and selectivity, making it a more ideal alternative to the precious metal platinum (Pt). Palladium can be introduced into various metal or non-metal elements (such as platinum (Pt), tin (Sn), copper (Cu), cobalt (Co), gold (Au), silver (Ag), vanadium (V), nickel (Ni), and tungsten (W)) to alloy or form intermetallic compounds, thereby preparing binary or ternary alloy catalysts or intermetallic compounds. This changes the lattice type and micromorphology of the precious metal palladium, thereby improving its catalytic performance and chemical tolerance.

[0018] The present invention adopts a simple, convenient and easy-to-operate hydrothermal preparation method to introduce the heavy metal element mercury (Hg) into the palladium element for alloying modification, thereby obtaining a palladium-based powder electrode material with a rod-like morphology. The material has potential application value in the field of direct alcohol fuel cells, and at the same time expands the application range of the heavy metal element mercury (Hg), which is conducive to the resource recovery and harmless utilization of the mercury element.

[0019] The present invention proposes a method for preparing a rod-shaped powder electrode material, which successfully introduces the heavy metal element mercury (Hg) into a palladium-based electrode material, thereby realizing the modification of the precious metal palladium element and the resource utilization of the heavy metal element mercury (Hg). The operation is simple and easy to implement. The prepared rod-shaped powder electrode material has potential application value in the field of direct alcohol fuel cells.

[0020] The powder electrode material prepared by the present invention has a particle size of 1 to 4 μm and a particle diameter of 0.3 to 1 μm. The powder electrode material mainly contains two elements: palladium (Pa) and mercury (Hg). In addition, it contains a small amount of phosphorus (P), chlorine (Cl), iodine (I) and other elements. The appearance is rod-like with many protrusions on the surface and uneven thickness.

[0021] The ethylene glycol and N,N-dimethylformamide mixed solvent of the present invention plays a role in shaping the microscopic morphology of the material and regulating its size. The powder electrode material prepared by the present invention contains a small amount of products with ellipsoidal morphology and lamellar morphology.

[0022] In step S2 of the present invention, washing with an ethanol solvent multiple times can remove ethylene glycol, N,N-dimethylformamide, unreacted precursor materials and other organic by-products attached to the surface of the reaction product; washing with a dilute nitric acid solution of a certain concentration multiple times can remove organic impurities and flaky alloys with very small particle sizes attached to the surface of the reaction product, while exposing more catalytic sites on the surface of the alloy material. The volume fraction of the dilute nitric acid is preferably 10% to 30%; after washing with an ethanol solvent or a dilute nitric acid solution, centrifugation is performed. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a scanning electron microscope photograph of the rod-shaped powder electrode material prepared by the present invention;

[0024] Figure 2 This is a transmission electron microscope photograph of the rod-shaped powder electrode material prepared in the present invention. DETAILED DESCRIPTION

[0025] The technical solution of the present invention is described in detail below through specific embodiments.

[0026] Example 1

[0027] A method for preparing a rod-shaped powder electrode material comprises the following steps:

[0028] S1. Prepare an organic mixed solvent of ethylene glycol and N,N-dimethylformamide in a volume ratio of 4:1, weigh bistriphenylphosphine palladium dichloride and mercuric iodide in a ratio of 1:1.5 in terms of the amount of substance, add bistriphenylphosphine palladium dichloride and mercuric iodide to the organic mixed solvent of ethylene glycol and N,N-dimethylformamide at the same time, mix evenly, and allow the precursor material to be completely integrated into the organic mixed solvent; weigh a certain amount of 2,3,5,6-tetrahydroxy-2-hexene-4-lactone, add it to the mixed solvent of ethylene glycol and N,N-dimethylformamide, ensuring that the amount of reducing agent added to 1L of the mixed solvent is 100 mg, stir evenly at room temperature, and then transfer it to a high-temperature and high-pressure reactor, and add a magnetic stirrer to the reactor. Then, pressurize and seal the high-temperature and high-pressure reactor and transfer it to a high-temperature drying oven, and react at a high temperature of 180°C for 6 hours, during which the magnetic stirrer is always in a high-speed stirring state;

[0029] S2. After the reaction is completed, cool to room temperature, centrifuge the product to separate the black precipitate at the bottom, add ethanol solvent to the centrifuge tube with the black precipitate, mix well and centrifuge, and repeat this process several times; then add a dilute nitric acid solution with a volume fraction of 10% to the black precipitate, mix well and centrifuge, and repeat this process several times; move the black precipitate after multiple washings into a vacuum drying oven and dry it for 12 hours to obtain a black rod-shaped electrode material.

[0030] Depend on Figure 1 and Figure 2 The prepared electrode material is primarily rod-shaped, with a small amount of ellipsoidal and lamellar morphologies. The surface of the electrode material has numerous tiny protrusions, which are the active sites for catalytic electrode reactions. This rod-shaped electrode material can be used as an anode material for direct alcohol fuel cells.

[0031] Example 2

[0032] A method for preparing a rod-shaped powder electrode material comprises the following steps:

[0033] S1. Prepare an organic mixed solvent of ethylene glycol and N,N-dimethylformamide in a volume ratio of 4:1, weigh bistriphenylphosphine palladium dichloride and mercuric iodide in a ratio of 1:6 in terms of the amount of substance, add bistriphenylphosphine palladium dichloride and mercuric iodide to the organic mixed solvent of ethylene glycol and N,N-dimethylformamide at the same time, mix evenly, and allow the precursor material to be completely integrated into the organic mixed solvent; weigh a certain amount of 2,3,5,6-tetrahydroxy-2-hexene-4-lactone, add it to the mixed solvent of ethylene glycol and N,N-dimethylformamide, ensuring that the amount of reducing agent added to 1L of the mixed solvent is 100 mg, stir evenly at room temperature, and then transfer it to a high-temperature and high-pressure reactor, and add a magnetic stirrer to the reactor. Then, pressurize and seal the high-temperature and high-pressure reactor and transfer it to a high-temperature drying oven, and react at a high temperature of 180°C for 6 hours, during which the magnetic stirrer is always in a high-speed stirring state;

[0034] S2. After the reaction is completed, cool to room temperature, centrifuge the product to separate the black precipitate at the bottom, add ethanol solvent to the centrifuge tube with the black precipitate, mix well and centrifuge, and repeat this process several times; then add a dilute nitric acid solution with a volume fraction of 10% to the black precipitate, mix well and centrifuge, and repeat this process several times; move the black precipitate after multiple washings into a vacuum drying oven and dry it for 12 hours to obtain a black rod-shaped electrode material, which can be used as a cathode material for direct alcohol fuel cells.

[0035] Example 3:

[0036] A method for preparing a rod-shaped powder electrode material comprises the following steps:

[0037] S1. Prepare an organic mixed solvent of ethylene glycol and N,N-dimethylformamide in a volume ratio of 4:1, weigh bis(triphenylphosphine)palladium dichloride and mercuric iodide in a ratio of 1:1.5, add bis(triphenylphosphine)palladium dichloride and mercuric iodide to the organic mixed solvent of ethylene glycol and N,N-dimethylformamide at the same time, mix them evenly, and allow the precursor material to be completely integrated into the organic mixed solvent; weigh a certain amount of 2,3,5,6-tetrahydroxy-2-hexene-4-lactone, add ethylene glycol and N,N-dimethylformamide organic mixed solvent, The reducing agent is added to 1 L of the mixed solvent, ensuring that the amount of reducing agent added is 100 mg, and the mixture is stirred evenly at room temperature; a certain amount of Cabot carbon black is weighed (ensuring that the loading amount of precious metal palladium is 15% by weight), added to the mixed solvent of ethylene glycol and N,N-dimethylformamide, stirred evenly at room temperature, and then transferred to a high-temperature and high-pressure reactor, and a magnetic stirrer is added to the reactor. The high-temperature and high-pressure reactor is then pressurized and sealed, and then transferred to a high-temperature drying oven and placed at 180°C for 6 hours, during which the magnetic stirrer is always in a high-speed stirring state;

[0038] S2. After the reaction is completed, cool to room temperature, centrifuge the product to separate the black precipitate at the bottom, add ethanol solvent to the centrifuge tube containing the black precipitate, mix well, and centrifuge, repeating this process multiple times; then add a 10% volume fraction of dilute nitric acid solution to the black precipitate, mix well, and centrifuge, repeating this process multiple times; wrap the washed black precipitate in tin foil and transfer it to a vacuum drying oven to dry for 12 hours to obtain a carbon-supported electrode material. This significantly reduces the amount of precious metal alloy material used, enhances the conductivity of the electrode material, and makes the electrode material more evenly dispersed, exposing more active sites. This carbon-supported electrode material can be used as an anode material for direct alcohol fuel cells.

[0039] Implementation Case 4

[0040] A method for preparing a rod-shaped powder electrode material comprises the following steps:

[0041] S1. Prepare an organic mixed solvent of ethylene glycol and N,N-dimethylformamide in a volume ratio of 4:1, weigh bis(triphenylphosphine)palladium dichloride and mercuric iodide in a ratio of 1:6, add bis(triphenylphosphine)palladium dichloride and mercuric iodide to the organic mixed solvent of ethylene glycol and N,N-dimethylformamide at the same time, mix well, and allow the precursor material to be completely integrated into the organic mixed solvent; weigh a certain amount of 2,3,5,6-tetrahydroxy-2-hexene-4-lactone, add ethylene glycol and N,N-dimethylformamide organic mixed solvent The amount of reducing agent added to 1 L of the mixed solvent was ensured to be 100 mg, and the mixture was stirred evenly at room temperature. A certain amount of Cabot carbon black (ensuring a loading of precious metal palladium of 15% wt) was weighed and added to a mixed solvent of ethylene glycol and N,N-dimethylformamide. The mixture was stirred evenly at room temperature and then transferred to a high-temperature and high-pressure reactor. A magnetic stirrer was added to the reactor. The high-temperature and high-pressure reactor was then pressurized and sealed, and then transferred to a high-temperature drying oven. The mixture was placed at 180°C for 6 hours, during which the magnetic stirrer was kept in a high-speed stirring state.

[0042] S2. After the reaction is completed, cool to room temperature, centrifuge the product to separate the black precipitate at the bottom, add ethanol solvent to the centrifuge tube containing the black precipitate, mix well, and centrifuge, repeating this process multiple times; then add a 10% volume fraction of dilute nitric acid solution to the black precipitate, mix well, and centrifuge, repeating this process multiple times; wrap the washed black precipitate in tin foil and transfer it to a vacuum drying oven to dry for 12 hours to obtain a carbon-supported electrode material. This significantly reduces the amount of precious metal alloy material used, enhances the conductivity of the electrode material, and makes the electrode material more evenly dispersed, exposing more active sites. This carbon-supported electrode material can be used as a cathode material for direct alcohol fuel cells.

[0043] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing a rod-shaped powder electrode material, characterized in that: The following steps are involved: S1. Adding a palladium precursor material and a mercury precursor material to an organic solvent at the same time, then adding a reducing agent, stirring evenly at room temperature, and reacting under high temperature and high pressure; S2. After the reaction is completed, the mixture is cooled to room temperature, the product is centrifuged, washed, and centrifuged again to obtain a black substance, which is then dried to obtain a black rod-shaped powder electrode material; In step S1, the palladium precursor material and the mercury precursor material are bistriphenylphosphine palladium dichloride and mercuric iodide, respectively, and the molar ratio of the palladium precursor material to the mercury precursor material is (1:1) to (1:6); In step S1, the organic solvent is a mixed solvent of ethylene glycol and N,N-dimethylformamide, and the volume ratio of ethylene glycol to N,N-dimethylformamide is (4:1) to (16:1); In step S1, the reducing agent is 2,3,5,6-tetrahydroxy-2-hexene-4-lactone, and 50 to 150 mg of the reducing agent is added to every 1 L of the mixed solvent.

2. The method for preparing a rod-shaped powder electrode material according to claim 1, characterized in that: In step S1, the reaction is carried out at a high temperature of 120-200° C. for 3-6 hours, and the organic solvent is always in a turbulent state during the reaction.

3. The method for preparing a rod-shaped powder electrode material according to claim 1, wherein: In step S2, ethanol solvent and dilute nitric acid are used to wash the sample multiple times.

4. The method for preparing a rod-shaped powder electrode material according to claim 3, characterized in that: The volume fraction of dilute nitric acid is 10% to 30%.

5. The method for preparing a rod-shaped powder electrode material according to claim 1, wherein: In step S2, the black substance is dried in a vacuum drying oven for 6 to 12 hours.

6. A rod-shaped powder electrode material prepared by the method according to any one of claims 1 to 5.

7. Use of the rod-shaped powder electrode material according to claim 6 in a direct alcohol fuel cell.

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