Method for preparing precious metal alloy material through supramolecular cage confinement path
By capturing the platinum-containing precursors in the supramolecular cage wrapped with polymer hydrogels around the carbon matrix, the Pt3Co alloy catalyst was prepared, which solved the problems of high platinum cost and reduced catalytic activity, and achieved efficient electrolytic hydrogen analysis performance.
Patent Information
- Application Number
- CN202411714780.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-27
- Publication Date
- 2025-04-15
AI Technical Summary
The high cost of platinum in existing electrolytic hydrogen-induced catalysts limits its large-scale application, and the increase in surface energy after reducing the size of platinum leads to a decrease in catalytic activity.
By encapsulating the polymer hydrogel in situ on the periphery of the carbon matrix, a fixed number of platinum-containing precursors are captured using a supramolecular cage to prepare a Pt3Co alloy catalyst with a specific ratio of platinum and cobalt.
High-efficiency electrolysis of hydrogen in alkaline media is achieved, the active site is enclosed, and the utilization efficiency and electrocatalytic performance of the catalyst are improved.
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Figure CN119824400A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of water electrolysis catalysts, and specifically relates to a method for preparing noble metal alloy materials through a supramolecular cage confinement path. Background Art
[0002] Electrocatalytic water splitting has been widely recognized as a promising route to produce green hydrogen from renewable electricity. Despite efforts to develop transition metal-based catalysts for water splitting, platinum remains the most promising catalyst for hydrogen evolution from water electrolysis for practical applications. However, the high cost of platinum has hindered its large-scale application. Therefore, the development of low-cost but highly efficient electrocatalysts is particularly important to address the above issues.
[0003] Reducing the size of Pt has been widely used to improve the utilization efficiency of Pt. However, the increase in surface energy may lead to Pt aggregation and severe decrease in catalytic activity, so the design of Pt-based alloys coupled with 3d transition metals has been applied to improve Pt catalytic activity and utilization efficiency.
[0004] Platinum-cobalt alloy catalysts have higher catalytic activity than pure platinum catalysts, mainly due to the synergistic effect between platinum and cobalt, which can enhance the adsorption and activation of reactants. Theoretical studies also show that compared with PtCo alloy catalysts, the adsorption Gibbs free energy of Pt3Co alloy catalysts is closer to zero, indicating that Pt3Co alloys have faster proton-electron transfer rates, thereby promoting the HER process, making it a more promising HER catalyst in alkaline media than other Pt-based alloys. Summary of the invention
[0005] The purpose of the present invention is to provide a method for preparing precious metal alloy materials by a supramolecular cage confinement path, by using a fixed-size supramolecular cage of a specific hydrogel to capture a fixed number of platinum-containing precursors, a specific ratio of platinum and cobalt is achieved, and an efficient water electrolysis hydrogen evolution catalyst material with a specific platinum-based alloy (Pt3Co) loaded on a carbon matrix is prepared.
[0006] The present invention adopts the following technical solution: A method for preparing a noble metal alloy material by a supramolecular cage confinement path, in situ wrapping a polymer hydrogel around a carbon matrix, using the supramolecular cage unique to the hydrogel to capture a fixed amount of platinum-containing precursors, to prepare the noble metal alloy material, specifically comprising the following steps: S1, dispersing carbon nanotubes acidified with sulfuric acid and nitric acid in deionized water containing pyrrole Py monomer to obtain solution A; S2, dispersing the cobalt-containing crosslinking agent and ammonium persulfate in deionized water, and mixing them thoroughly within 1 hour to obtain a mixed solution B; S3, adding solution A to mixed solution B to quickly obtain a black hydrogel, washing it with deionized water, and vacuum drying it at 80°C overnight to obtain a hydrogel; S4, carbonizing the hydrogel at 900°C in an Ar atmosphere for 2 h to obtain hydrogel-derived carbon; S5, adding chloroplatinic acid to deionized water containing hydrogel-derived carbon, heating in a water bath at 60°C for 16 h, washing with deionized water and ethanol five times, and drying overnight to obtain a Pt-containing precursor; S6. Heat the Pt-containing precursor at 700° C. in a H2 / Ar atmosphere for 2 h to obtain a black solid powder.
[0007] Furthermore, in S1, the usage ratio of the acidified carbon nanotubes, the pyrrole Py monomer, and the deionized water is 5-20 mg: 28-112 μL: 0.5-2 mL.
[0008] Furthermore, in S2, the cobalt-containing cross-linking agent is 5,10,15,20-tetrakis(4-carboxyphenyl)-Co; the usage ratio of the cobalt-containing cross-linking agent, ammonium persulfate, and deionized water is 9-34 mg: 92-366 mg: 0.5-2 mL.
[0009] Furthermore, in S5, the usage ratio of chloroplatinic acid, hydrogel-derived carbon, and deionized water is 200-1000 μL: 20-100 mg: 4-20 mL.
[0010] Furthermore, the morphology of the hydrogel-derived carbon and the size of the supramolecular cage obtained after carbonization remain unchanged.
[0011] Furthermore, the supramolecular cage of the hydrogel-derived carbon can capture three Pt precursors.
[0012] During the monomer gelation process of the present invention, around the carbon nanotubes, four carboxyl groups in the cross-linking agent are cross-linked with polypyrrole (PPy) through hydrogen bonds and electrostatic interactions to form a supramolecular cage with a width of about 18 Å; three platinum-containing precursors with a width of about 5 Å can be captured to form a confinement domain.
[0013] The beneficial effects of the present invention are as follows: The present invention utilizes hydrogel to wrap around the periphery of carbon nanotubes. The unique supramolecular cage of the peripheral hydrogel can capture three platinum-containing precursors. During the pyrolysis process, platinum is coupled with the surrounding cobalt to form Pt3Co alloy particles. The platinum in the precursor is confined in the peripheral hydrogel and does not enter the interior of the carbon nanotubes, so there is no active site being buried, thereby making the material have excellent water electrolysis and hydrogen evolution performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 This is a SEM image of the hydrogel-wrapped carbon nanotubes prepared in Example 1; Figure 2 This is a SEM image of the carbonized hydrogel-wrapped carbon nanotubes prepared in Example 1; Figure 3 TEM image of the derived carbon prepared in Example 1 capturing the platinum-containing precursor; Figure 4 TEM image of the Pt3Co alloy material prepared in Example 1; Figure 5 This is the XRD image of the Pt3Co alloy material prepared in Example 1; Figure 6 The performance of the AEMWE device of the Pt3Co alloy material prepared in Example 1 at different temperatures; Figure 7 TEM image of the Pt3Co alloy material prepared in Example 2; Figure 8 TEM image of the Pt3Co alloy material prepared in Example 3. DETAILED DESCRIPTION
[0015] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below, but the protection scope of the present invention is not limited to the following embodiments.
[0016] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, and the disclosure and materials cited therein are hereby incorporated by reference.
[0017] Technical equivalents to the specific embodiments described that are apparent to those skilled in the art using no more than routine experimentation are intended to be encompassed by this application.
[0018] The experimental methods in the following examples are all conventional methods unless otherwise specified. The instruments and equipment used in the following examples are all conventional laboratory instruments and equipment unless otherwise specified; the experimental materials used in the following examples are all purchased from conventional biochemical reagent stores unless otherwise specified.
[0019] Example 1 A method for preparing a noble metal alloy material by a supramolecular cage confinement path, the specific method is as follows: (1) Disperse 5 mg of carbon nanotubes acidified with sulfuric acid and nitric acid in 1 mL of deionized water containing 28 µL of pyrrole Py monomer to obtain solution A; disperse 9 mg of 5,10,15,20-tetrakis(4-carboxyphenyl)-Co and 92 mg of ammonium persulfate in 1 mL of deionized water and mix thoroughly within 1 h to obtain a mixed solution B; add solution A to solution B to quickly obtain a black hydrogel, wash it with deionized water, and dry it in vacuum at 80 °C overnight to obtain a hydrogel; (2) carbonizing the hydrogel at 900 °C in an Ar atmosphere for 2 hours to obtain hydrogel-derived carbon; (3) Add 500 μL of chloroplatinic acid to 10 mL of deionized water containing 50 mg of hydrogel-derived carbon, heat in a water bath at 60 °C for 16 h, wash with deionized water and ethanol five times, and dry overnight to obtain a Pt-containing precursor; (4) The Pt-containing precursor obtained in the above step was heated at 700 °C in a H2 / Ar atmosphere for 2 hours to obtain a black solid powder.
[0020] Figure 1 This is a SEM image of the hydrogel-wrapped carbon nanotube prepared in Example 1. As can be seen from the figure, after the hydrogel is wrapped around the carbon nanotube, it takes on the shape of the carbon nanotube and has a smooth surface.
[0021] Figure 2 This is a SEM image of the carbonized hydrogel-wrapped carbon nanotubes prepared in Example 1. As can be seen from the figure, the morphology of the carbonized material remains basically unchanged, indicating that high-temperature carbonization has little effect on the cross-linked porous structure of the material.
[0022] Figure 3 This is a TEM image of the derived carbon captured by the platinum-containing precursor prepared in Example 1. As can be seen from the figure, there are no obvious particles in the material, indicating that the platinum element is confined on the substrate in the form of atoms or clusters, indicating the effectiveness of supramolecular cage confinement.
[0023] Figure 4 This is a TEM image of the Pt3Co alloy material prepared in Example 1. As can be seen from the figure, particles appear in the material, with a size between 2 and 3 nm.
[0024] Figure 5 This is the XRD image of the Pt3Co alloy material prepared in Example 1. As can be seen from the figure, the characteristic diffraction peaks of the material correspond well to the JCPDS standard card (No. 29-0499), indicating that Pt and Co are fused into Pt3Co alloy at high temperature.
[0025] Figure 6The performance of the Pt3Co alloy material prepared in Example 1 at different temperatures in the AEMWE device. AEM water electrolysis is an electrochemical water decomposition technology that uses a dilute alkaline solution or pure water as an electrolyte. The electrochemical water decomposition reaction consists of two half-cell reactions: the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). This material is used for the hydrogen evolution reaction of alkaline electrochemical water decomposition. When the reaction reaches a certain current density, the smaller the voltage required, the better the hydrogen evolution performance of the material. As can be seen from the figure, at 70 ° C, the Pt3Co alloy material only needs 1.847 V to reach 500 mA cm -2 , 2.009 V is required to achieve 1 Acm -2 , indicating that the catalyst of the present invention has good electrocatalytic application prospects.
[0026] Example 2 A method for preparing a noble metal alloy material by a supramolecular cage confinement path, the specific method is as follows: (1) Acidified carbon nanotubes (15 mg) were dispersed in 1.5 mL of deionized water containing 84 μL of pyrrole Py monomer to obtain solution A; 25 mg of 5,10,15,20-tetrakis(4-carboxyphenyl)-Co and 274 mg of ammonium persulfate were dispersed in 2 mL of deionized water and mixed thoroughly within 1 h to obtain a mixed solution B; solution A was added to solution B to quickly obtain a black hydrogel, which was washed with deionized water and dried at 80 °C in vacuum overnight to obtain a hydrogel; (2) The above hydrogel was carbonized at 900 °C in an Ar atmosphere for 2 hours to obtain a hydrogel-derived carbon; (3) 500 μL of chloroplatinic acid was added to 10 mL of deionized water containing 50 mg of hydrogel-derived carbon, heated in a water bath at 60 °C for 16 hours, washed with deionized water and ethanol five times, and dried overnight to obtain a Pt-containing precursor; (4) The Pt-containing precursor obtained in the above steps was carbonized at 700 °C in a H2 / Ar atmosphere. Heating at ℃ for 2 hours gave a black solid powder.
[0027] Figure 7 This is a TEM image of the Pt3Co alloy material prepared in Example 2. As can be seen from the figure, there are particles in the material and there are obvious Pt3Co lattice fringes.
[0028] Example 3 A method for preparing a noble metal alloy material by a supramolecular cage confinement path, the specific method is as follows: (1) Acidified carbon nanotubes (20 mg) were dispersed in 2 mL of deionized water containing 112 μL of pyrrole Py monomer to obtain solution A; 34 mg of 5,10,15,20-tetrakis(4-carboxyphenyl)-Co and 366 mg of ammonium persulfate were dispersed in 2 mL of deionized water and mixed thoroughly within 1 h to obtain a mixed solution B; solution A was added to solution B to quickly obtain a black hydrogel, which was washed with deionized water and dried at 80 °C in vacuum overnight to obtain a hydrogel; (2) The above hydrogel was carbonized at 900 °C in an Ar atmosphere for 2 hours to obtain a hydrogel-derived carbon; (3) 500 μL of chloroplatinic acid was added to 10 mL of deionized water containing 50 mg of hydrogel-derived carbon, heated in a water bath at 60 °C for 16 hours, washed with deionized water and ethanol five times, and dried overnight to obtain a Pt-containing precursor; (4) The Pt-containing precursor obtained in the above steps was carbonized at 700 °C in a H2 / Ar atmosphere. Heating at ℃ for 2 hours gave a black solid powder.
[0029] Figure 8 This is a TEM image of the Pt3Co alloy material prepared in Example 3. As can be seen from the figure, particles exist in the material.
[0030] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A method for preparing precious metal alloy materials by a supramolecular cage confinement pathway, characterized in that: The steps include: S1, dispersing carbon nanotubes acidified with sulfuric acid and nitric acid in deionized water containing pyrrole Py monomer to obtain solution A; S2, dispersing the cobalt-containing crosslinking agent and ammonium persulfate in deionized water, and mixing them thoroughly within 1 hour to obtain a mixed solution B; S3, adding solution A to mixed solution B to quickly obtain a black hydrogel, washing it with deionized water, and vacuum drying it at 80°C overnight to obtain a hydrogel; S4, carbonizing the hydrogel at 900°C in an Ar atmosphere for 2 h to obtain hydrogel-derived carbon; S5, adding chloroplatinic acid to deionized water containing hydrogel-derived carbon, heating in a water bath at 60°C for 16 h, washing with deionized water and ethanol five times, and drying overnight to obtain a Pt-containing precursor; S6. Heat the Pt-containing precursor at 700° C. in a H2 / Ar atmosphere for 2 h to obtain a black solid powder.
2. The method for preparing a noble metal alloy material by a supramolecular cage confinement pathway according to claim 1, characterized in that: In S1, the usage ratio of the acidified carbon nanotubes, the pyrrole Py monomer, and the deionized water is 5-20 mg: 28-112 μL: 0.5-2 mL.
3. The method for preparing a noble metal alloy material by a supramolecular cage confinement pathway according to claim 1, characterized in that: In S2, the cobalt-containing cross-linking agent is 5,10,15,20-tetrakis(4-carboxyphenyl)-Co; the usage ratio of the cobalt-containing cross-linking agent, ammonium persulfate, and deionized water is 9-34 mg: 92-366 mg: 0.5-2 mL.
4. The method for preparing a noble metal alloy material by a supramolecular cage confinement pathway according to claim 1, characterized in that: In S5, the usage ratio of chloroplatinic acid, hydrogel-derived carbon, and deionized water is 200-1000 μL: 20-100 mg: 4-20 mL.
5. The method for preparing a noble metal alloy material by a supramolecular cage confinement pathway according to claim 1, characterized in that: The morphology of the hydrogel-derived carbon and the size of the supramolecular cages obtained after carbonization remain unchanged.
6. The method for preparing a noble metal alloy material by a supramolecular cage confinement pathway according to claim 1, characterized in that: The supramolecular cage of the hydrogel-derived carbon can capture three Pt precursors.