A hydrophilic carbon-based modified high-entropy alloy catalyst for water electrolysis to produce hydrogen, its preparation method and application.

Abstract

This invention discloses a hydrophilic carbon-based modified high-entropy alloy water electrolysis hydrogen production catalyst, its preparation method, and its application, belonging to the field of catalyst preparation technology. The method includes: 1) adding a hydrophilic carbon-based material and a mixed metal salt to an ethylene glycol solution, ultrasonically mixing to obtain a reaction solution; 2) heating the ethylene glycol solution to 200-240°C in an oil bath, then slowly adding the reaction solution obtained in step 1), heating for 0.5-2 h, cooling, and centrifuging to obtain the carbon-based modified high-entropy alloy water electrolysis hydrogen production catalyst. The hydrophilic carbon-based modified high-entropy alloy water electrolysis hydrogen production catalyst prepared by this invention has high activity, and the generated hydrogen bubbles are smaller and more easily detach from the electrode surface.

Description

Technical Field

[0001] This invention belongs to the field of catalyst preparation technology, and relates to a method and application of modifying high-entropy alloy water electrolysis catalysts with hydrophilic carbon-based materials. Specifically, it relates to a hydrophilic carbon-based modified high-entropy alloy water electrolysis hydrogen production catalyst, its preparation method, and its application. Background Technology

[0002] The ever-increasing global energy demand, coupled with the gradual depletion of fossil fuels and environmental degradation, has spurred an urgent search for renewable energy sources such as wind and solar power. However, a time lag often exists between the supply and demand of these sustainable energy sources. Water electrolysis is a promising clean and sustainable hydrogen production technology. Hydrogen, with its high calorific value, clean combustion products, and renewable nature, is one of the most ideal energy carriers. Finding a green and efficient method for hydrogen production is a major challenge for the large-scale utilization of hydrogen energy. Electrochemical water splitting technology not only converts electrical energy into chemical energy in an environmentally friendly way but also can be easily combined with other intermittent energy sources such as wind and solar power, providing a promising solution for the production of high-purity hydrogen.

[0003] High-entropy alloy catalysts possess advantages such as high efficiency, stability, and reusability, making them perfectly suited for the electrolysis of water to produce hydrogen. However, when designing highly efficient catalysts, in addition to considering the catalytic material, the formation and release of hydrogen bubbles on the catalyst surface should also be taken into account, as this significantly affects catalytic performance. Hydrogen bubbles adhering to the catalyst surface reduce the effective specific surface area, increase the activation overpotential, and act as blockages for ion transport through the electrolyte, leading to an increase in the catalyst's overpotential. Furthermore, the evolution of hydrogen bubbles generates significant tensile forces, which can damage the catalyst when they detach, thus reducing its stability. In water electrolysis experiments, applying external force by stirring the electrolyte to promote the faster detachment of hydrogen bubbles generated during electrolysis from the electrode surface is indeed a common method. This approach can effectively reduce the impact of bubbles on the electrolysis reaction and improve electrolysis efficiency. However, applying external force by stirring the electrolyte is not practical for large-scale industrial production because continuous stirring increases energy consumption and may complicate equipment. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a hydrophilic carbon-based modified high-entropy alloy water electrolysis hydrogen production catalyst, its preparation method and application, so as to solve the technical problem that there are many hydrogen bubbles on the surface of the existing water electrolysis hydrogen production catalyst, and the influence of hydrogen bubbles must be eliminated by stirring during the water electrolysis process.

[0005] To achieve the above objectives, the present invention employs the following technical solution:

[0006] This invention discloses a method for modifying a high-entropy alloy water electrolysis hydrogen production catalyst with a hydrophilic carbon-based material, comprising:

[0007] A hydrophilic carbon-based material and a mixed metal salt were added to an ethylene glycol solution and ultrasonically mixed to obtain a reaction solution. The reaction solution was then heat-treated in an oil bath at 200-240℃ for 0.5-2 h, cooled, and centrifuged to obtain a hydrophilic carbon-based material modified high-entropy alloy electrolysis hydrogen production catalyst.

[0008] Preferably, it includes the following steps:

[0009] 1) Add the hydrophilic carbon-based material and the mixed metal salt to the ethylene glycol solution and mix them evenly by ultrasonication to obtain the reaction solution;

[0010] 2) Heat the ethylene glycol solution to 200-240℃ in an oil bath, then slowly add the reaction solution obtained in step 1), and heat for 0.5-2 h. After cooling, centrifuge to obtain the carbon-based modified high-entropy alloy electrolytic hydrogen production catalyst.

[0011] Preferably, the hydrophilic carbon-based material is selected from hydrophilic carbon black, hydrophilic carbon cloth, or hydrophilic biochar material.

[0012] Preferably, the ethylene glycol solution has a purity of 99.7% (Gas Chromatography, GC).

[0013] Preferably, the mixed metal salt is prepared from platinum salt, palladium salt, cobalt salt, nickel salt and copper salt.

[0014] More preferably, the mixed metal salt is selected from acetylacetone metal salt.

[0015] More preferably, the mixed metal salt is prepared from equal molar masses of platinum acetylacetonate, palladium acetylacetonate, cobalt acetylacetonate, nickel acetylacetonate, and copper acetylacetonate.

[0016] Preferably, in step 1), the ratio of carbon-based material to mixed metal salt is (0.3-0.4) mg: (0.1-0.2) mmol.

[0017] Preferably, in step 1), the ultrasonic mixing time is 0.25-0.75 h.

[0018] Preferably, in step 2), the reaction solution is in the form of 230-260 μL. -1 The solution is slowly added dropwise to an ethylene glycol solution heated in an oil bath. At this dropping rate, the reaction is more complete, and the product particles have a more uniform size distribution.

[0019] The present invention also discloses a carbon-based modified high-entropy alloy water electrolysis hydrogen production catalyst prepared by the above method, wherein the carbon-based modified high-entropy alloy water electrolysis hydrogen production catalyst has enhanced hydrophilicity.

[0020] The present invention also discloses the application of the above-mentioned carbon-based modified high-entropy alloy electrolysis hydrogen production catalyst in the electrolysis hydrogen production reaction.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention discloses a method for modifying a mixed metal salt high-entropy alloy electrolytic water production hydrogen catalyst using hydrophilic carbon-based materials. On one hand, to optimize catalyst performance and enhance its hydrophilicity, this invention selects hydrophilic carbon-based materials to enhance the catalyst's hydrophilicity. Adding these materials effectively improves the catalyst's surface properties, making it easier for generated hydrogen bubbles to detach, thereby reducing gas accumulation and improving reaction efficiency. On the other hand, before the reaction, the reaction solution containing the mixed metal salts is uniformly mixed and slowly added dropwise to the reaction solvent. This operation ensures uniform particle size and elemental distribution of the raw materials during catalyst preparation, contributing to improved catalytic efficiency and selectivity. This uniform structure provides more catalytic sites, promoting the adsorption and conversion of reactants, thus enhancing the performance of water electrolysis for hydrogen production. Furthermore, the uniform elemental distribution helps optimize the catalyst's electronic and ionic conductivity, further improving the overall catalytic effect. Therefore, this invention, combining these two inventive points, achieves an innovative solution that maintains catalyst activity while improving its surface hydrophilicity, resulting in a more efficient electrocatalytic reaction. This optimization method provides new ideas for the design and application of electrocatalysts, which helps to promote the development of renewable energy technologies. Attached Figure Description

[0023] Figure 1 This is a flowchart illustrating the preparation process of the high-entropy alloy catalyst of the present invention.

[0024] Figure 2 These are X-ray diffraction images of the high-entropy alloy catalysts prepared in three embodiments of the present invention;

[0025] Figure 3 This is a scanned image of the PtPdCoNiCu high-entropy alloy catalyst prepared in Example 1;

[0026] Figure 4 The image shows a scanned image of the PtPdCoNiCu-Graphene high-entropy alloy catalyst prepared in Example 2.

[0027] Figure 5 This is a scanned image of the PtPdCoNiCu-CB high-entropy alloy catalyst prepared in Example 3;

[0028] Figure 6 The image shows the contact angle of the PtPdCoNiCu high-entropy alloy catalyst prepared in Example 1.

[0029] Figure 7 The image shows the contact angle of the PtPdCoNiCu-Graphene high-entropy alloy catalyst prepared in Example 2.

[0030] Figure 8 The image shows the contact angle of the PtPdCoNiCu-CB high-entropy alloy catalyst prepared in Example 3.

[0031] Figure 9 The high-entropy alloy catalysts prepared in the three embodiments of the present invention are the hydrogen evolution reaction polarization curves obtained by linear sweep voltammetry.

[0032] Figure 10 The graphs are local fitting curves of the hydrogen evolution reaction polarization curves of the high-entropy alloy catalysts prepared in the three embodiments of the present invention, corresponding to the linear sweep voltammetry method. Detailed Implementation

[0033] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0034] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0035] The present invention will now be described in further detail with reference to the accompanying drawings:

[0036] The process flow of the high-entropy alloy electrolysis water production hydrogen catalyst in all embodiments of the present invention is as follows: Figure 1 As shown, the synthesis is carried out via a simple one-step solvothermal method, including the following steps:

[0037] 1) Prepare a mixed solution of metal salts, adding or omitting carbon-based materials as needed, as the reaction solution;

[0038] 2) Under oil bath conditions, the reaction solution was added for heat treatment, and after cooling and centrifugation, a high-entropy alloy catalyst for water electrolysis to produce hydrogen was obtained.

[0039] Example 1: No carbon-based materials added

[0040] A method for preparing a PtPdCoNiCu high-entropy alloy catalyst includes the following steps:

[0041] 1) Weigh platinum acetylacetonate (Pt), palladium acetylacetonate (Pd), cobalt acetylacetonate (Co), nickel acetylacetonate (Ni), and copper acetylacetonate (Cu) with the same molar mass. The total mass of the mixed metal salts weighed is 38.0 mg. Add the weighed drugs to 5 mL of ethylene glycol solution and sonicate them evenly.

[0042] The specific preparation process is as follows: Weigh 0.025 mmol of metal salt on a balance and place it in a beaker containing 5 mL of ethylene glycol solution, and sonicate for 0.5 h.

[0043] 2) Add 5 mL of ethylene glycol solution to the flask and heat it to 220 °C using an oil bath.

[0044] The specific preparation process involves adding 5 mL of ethylene glycol and a magnetic stir bar into a flask. During the oil bath heating process, the magnetic stir bar must also be kept rotating to ensure that the solution is heated evenly.

[0045] 3) The ultrasonically homogenized reaction solution was slowly added dropwise to a flask and reacted at 220 °C to obtain a PtPdCoNiCu high-entropy alloy electrocatalyst.

[0046] The specific preparation process involves transferring the reaction solution through a pipette at a rate of 230-260 μL / s. -1 It is slowly added dropwise into the flask.

[0047] Example 2: Addition of hydrophobic carbon-based materials

[0048] A method for preparing a PtPdCoNiCu-Graphene high-entropy alloy catalyst includes the following steps:

[0049] 1) Weigh it on a balance and add it to the ethylene glycol solution and mix well.

[0050] Specifically, first, weigh 0.025 mmol of platinum acetylacetonate (Pt), 0.025 mmol of palladium acetylacetonate (Pd), 0.025 mmol of cobalt acetylacetonate (Co), 0.025 mmol of nickel acetylacetonate (Ni), 0.025 mmol of copper acetylacetonate (Cu), and 0.4 mg of hydrophobic graphene powder (0.4 mg is theoretically 4% of the mass of the high-entropy alloy formed by the complete reaction of 0.025 mmol of metal salt solution). Then, add 5 mL of ethylene glycol solution to the weighed reagents and sonicate them for 0.5 h to obtain the reaction solution.

[0051] 2) Add 5 mL of ethylene glycol solution to the flask and heat to 220 °C using an oil bath.

[0052] The specific preparation process involves adding 5 mL of ethylene glycol and a magnetic stir bar into a flask. During the oil bath heating process, the magnetic stir bar must also be kept rotating to ensure that the solution is heated evenly.

[0053] 3) The ultrasonically homogenized reaction solution was slowly added dropwise to the flask, and the reaction was carried out at 220 °C. This yielded a PtPdCoNiCu-Graphene high-entropy alloy catalyst.

[0054] The specific preparation process involves: taking the ultrasonically homogenized reaction solution (ethylene glycol solution containing metal salt) from step 1), and mixing it at a rate of 230-260 μL. -1 The catalyst was slowly added dropwise to a flask at 220 °C. The flask was heated at 220 °C for 1 h. After cooling, the PtPdCoNiCu-Graphene high-entropy alloy catalyst powder was obtained by centrifugation.

[0055] Example 3: Addition of hydrophilic carbon-based materials

[0056] A method for preparing a PtPdCoNiCu-CB high-entropy alloy catalyst includes the following steps:

[0057] 1) Weigh it on a balance and add it to the ethylene glycol solution and mix well.

[0058] Specifically, first, weigh 0.025 mmol of platinum acetylacetonate (Pt), 0.025 mmol of palladium acetylacetonate (Pd), 0.025 mmol of cobalt acetylacetonate (Co), 0.025 mmol of nickel acetylacetonate (Ni), 0.025 mmol of copper acetylacetonate (Cu), and 0.4 mg of hydrophilic carbon black powder (0.4 mg is theoretically 4% of the mass of the high-entropy alloy formed by the complete reaction of 0.025 mmol of metal salt solution). Then, add 5 mL of ethylene glycol solution to the weighed reagents and sonicate them for 0.5 h to obtain the reaction solution.

[0059] 2) Add 5 mL of ethylene glycol solution to the flask and heat it to 220 °C using an oil bath.

[0060] The specific preparation process involves adding 5 mL of ethylene glycol and a magnetic stir bar into a flask. During the oil bath heating process, the magnetic stir bar must also be kept rotating to ensure that the solution is heated evenly.

[0061] 3) The ultrasonically homogenized reaction solution was slowly added dropwise to the flask, and the reaction was carried out at 220 °C. This yielded a PtPdCoNiCu-CB high-entropy alloy catalyst.

[0062] The specific preparation process involves: mixing the previously sonicated reaction solution (ethylene glycol solution containing metal salt) at a concentration of 230-260 μL. -1 The catalyst was slowly added dropwise to a flask at 220 °C. The flask was heated at 220 °C for 1 h. After cooling, the PtPdCoNiCu-CB high-entropy alloy catalyst powder was obtained by centrifugation.

[0063] The PtPdCoNiCu high-entropy alloy electrocatalyst prepared in Example 1, the PtPdCoNiCu-Graphene high-entropy alloy catalyst prepared in Example 2, and the PtPdCoNiCu-CB high-entropy alloy catalyst prepared in Example 3 were subjected to corresponding structural and performance tests, and the results are as follows. Figures 2-10 As shown. The specific analysis is as follows:

[0064] See Figure 2The figures show X-ray diffraction (XRD) images of the three high-entropy alloy catalysts prepared. As can be seen from the figures, the PtPdCoNiCu-Graphene high-entropy alloy catalyst synthesized in Example 2 mainly has three peaks in the range of 20–80°. These three peaks are located at 42°, 47°, and 71°, respectively. The positions of these peaks are different from the peaks of single atoms of Pt, Pd, Co, Ni, and Cu, but are the same as the peaks of the PtPdCoNiCu high-entropy alloy catalyst prepared in Example 1, and are located in the middle of the (1 1 1), (2 0 0), and (2 2 0) crystal planes of single atoms of Pt, Pd, Co, Ni, and Cu, respectively. This indicates that the peaks formed by the PtPdCoNiCu-Graphene high-entropy alloy catalyst are the peaks formed by their alloy, and are located on the (1 1 1), (2 0 0), and (2 2 0) crystal planes, respectively.

[0065] at the same time, Figure 2 The PtPdCoNiCu-CB high-entropy alloy catalyst prepared in Example 3 mainly has three peaks in the range of 20~80°. These three peaks are at 42°, 47° and 71° respectively. The positions of these peaks are the same as those of Pt, Pd, Co, Ni and the PtPdCoNiCu high-entropy alloy catalyst prepared in Example 1, and they are located in the middle of the (1 11), (2 0 0) and (2 2 0) crystal planes of Pt, Pd, Co, Ni and Cu single atoms, respectively. This indicates that the peaks formed by the PtPdCoNiCu-CB high-entropy alloy catalyst are the peaks formed by their alloy, and are the (1 1 1), (2 0 0) and (2 2 0) crystal planes respectively.

[0066] See Figure 3 The image shows a scanning field emission electron microscope (SEM) image of the PtPdCoNiCu high-entropy alloy catalyst prepared in Example 1. The image shows that the PtPdCoNiCu high-entropy alloy catalyst consists of relatively uniformly sized particles.

[0067] See Figure 4 The image shows a scanning field emission electron microscope (SEM) image of the PtPdCoNiCu-Graphene catalyst prepared in Example 2. The image shows that the PtPdCoNiCu-Graphene catalyst consists of relatively uniformly sized particles.

[0068] See Figure 5 The image shows a scanning field emission electron microscope (SEM) image of the PtPdCoNiCu-CB high-entropy alloy catalyst prepared in Example 3. The image shows that the PtPdCoNiCu-CB high-entropy alloy catalyst consists of relatively uniformly sized particles.

[0069] See Figure 6The image shows the contact angle of the PtPdCoNiCu high-entropy alloy catalyst prepared in Example 1. As can be seen from the image, its contact angle is 65.1°.

[0070] See Figure 7 The image shows the contact angle of the PtPdCoNiCu-Graphene high-entropy alloy catalyst prepared in Example 2. As can be seen from the image, its contact angle is 71.4°, indicating a decrease in hydrophilicity compared to the PtPdCoNiCu high-entropy alloy catalyst prepared in Example 1.

[0071] See Figure 8 The image shows the contact angle of the PtPdCoNiCu-CB high-entropy alloy catalyst prepared in Example 3. As can be seen from the image, the contact angle of the PtPdCoNiCu-CB high-entropy alloy catalyst is 58.3°, which indicates enhanced hydrophilicity compared to the PtPdCoNiCu high-entropy alloy catalyst prepared in Example 1.

[0072] See Figure 9 and Figure 10 The figures show the polarization curves of the high-entropy alloy catalysts prepared in the three examples, obtained by linear sweep voltammetry, and the fitting results of their fluctuations. Figure 9 It can be seen that the catalyst performance decreases slightly under high current conditions after the addition of acetylene black (j>0.75 A cm). -2 Furthermore, the stability of the catalyst is weakened. Figure 10 It can be seen that after adding acetylene black, the catalyst under high current conditions (j>0.75 A cm⁻¹) -2 The performance of the catalyst was improved, and its volatility under high current conditions was reduced.

[0073] Furthermore, through performance and activity analysis of the two carbon-based modified high-entropy alloy catalysts prepared in Examples 2 and 3, it can be seen that adding hydrophobic graphene to the reaction solution of the synthesized catalyst to increase the active surface area of ​​the catalyst can theoretically improve the performance of the electrocatalyst. However, experimental results show that the addition of hydrophobic materials weakens the hydrophilicity of the catalyst, making it difficult for the generated hydrogen bubbles to detach, resulting in more bubbles covering the electrode surface and thus affecting the performance of the catalyst. This phenomenon may lead to gas accumulation, thereby reducing the reaction efficiency. Therefore, to further optimize the performance of the catalyst, the present invention adds hydrophilic carbon black powder to the reaction solution of the synthesized catalyst to enhance its hydrophilicity. Experimental results show that the addition of this hydrophilic material can improve the surface properties of the catalyst, making it easier for the generated hydrogen bubbles to detach, thereby reducing gas accumulation and improving the reaction efficiency.

[0074] In summary, this invention synthesizes platinum acetylacetonate (C) via a simple one-step solvothermal method, by adding the same amount of platinum acetylacetonate (C) to the reaction solution. 10 H 14 O4Pt), palladium acetylacetonate (C 10 H 16 O4Pd), cobalt acetylacetonate (C 10 H 16 CoO4), nickel acetylacetonate (C 10 H 14 NiO4) and copper acetylacetonate (C 10 H 14 CuO4) and a certain amount of carbon material are added to synthesize a powdered catalyst. The synthesized catalyst is then prepared into a catalyst ink, which is drop-coated onto a glassy carbon electrode, dried in air, and then used in an electrochemical reaction.

[0075] The PtPdCoNiCu-CB high-entropy alloy catalyst prepared in this invention exhibits enhanced hydrophilicity compared to the PtPdCoNiCu high-entropy alloy catalyst. This increased hydrophilicity influences the bubbles on the electrode surface during electrolysis, thereby improving the catalyst's reactivity and performance under high-current conditions. Furthermore, the enhanced hydrophilicity also makes the catalyst more stable during operation.

[0076] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A method for preparing a hydrophilic carbon-based material modified high-entropy alloy catalyst for hydrogen production by water electrolysis, characterized in that, The method comprises the following steps: 1) adding a hydrophilic carbon-based material and a mixed metal salt into an ethylene glycol solution, and uniformly mixing by ultrasonic to obtain a reaction solution; the mixed metal salt is prepared by the same molar amount of platinum salt, palladium salt, cobalt salt, nickel salt and copper salt; the amount ratio of the hydrophilic carbon-based material and the mixed metal salt is (0.3-0.4) mg:(0.1-0.2) mmol; 2) Under oil bath conditions of 200-240℃, the reaction solution obtained in step 1) is added at a rate of 230-260 μL / s. -1 The catalyst was slowly added dropwise to an ethylene glycol solution heated in an oil bath, heated for 0.5-2 h, cooled, and then centrifuged to obtain a hydrophilic carbon-based modified high-entropy alloy catalyst for water electrolysis to produce hydrogen.

2. The method for preparing a hydrophilic carbon-based material modified high-entropy alloy catalyst for electrolytic water hydrogen production according to claim 1, characterized in that, The hydrophilic carbon-based material is selected from hydrophilic carbon black, hydrophilic carbon cloth or hydrophilic biochar material.

3. The method for preparing a hydrophilic carbon-based material modified high-entropy alloy water electrolysis hydrogen production catalyst according to claim 1, characterized in that, The purity of the ethylene glycol solution is 99.7%.

4. The method for preparing a water electrolysis hydrogen production catalyst of a high-entropy alloy modified by a hydrophilic carbon-based material according to claim 1, characterized in that, The mixed metal salt is prepared by the same molar amount of platinum acetylacetonate, palladium acetylacetonate, cobalt acetylacetonate, nickel acetylacetonate and copper acetylacetonate.

5. The method for preparing a water electrolysis hydrogen production catalyst of a high-entropy alloy modified by a hydrophilic carbon-based material according to claim 1, characterized in that, In step 1), the ultrasonic mixing time is 0.25-0.75 h.

6. A hydrophilic carbon-based material modified high-entropy alloy water electrolysis hydrogen production catalyst prepared by the preparation method in any one of claims 1-5.

7. Application of the hydrophilic carbon-based material modified high-entropy alloy water electrolysis hydrogen production catalyst in claim 6 in a water electrolysis hydrogen production reaction.

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