Graphene foam-based water electrolysis hydrogen evolution electrode and preparation method thereof
A hydrothermal method for preparing noble metal electrocatalysts by loading noble metal nanoparticles onto graphene foam has solved the problems of high cost and poor stability, achieving efficient and stable hydrogen evolution performance in water electrolysis, which is suitable for industrial applications.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SANYA SCI & EDUCATION INNOVATION PARK WUHAN UNIV OF TECH
- Filing Date
- 2023-03-21
- Publication Date
- 2026-05-22
AI Technical Summary
In existing technologies, noble metal-based acidic/alkaline electrocatalysts are costly and have unsatisfactory stability. Traditional electrodeposition methods result in uneven loading and noble metal agglomeration, making it difficult to form nanostructures and leading to unstable preparation processes.
Noble metal ions are loaded onto a graphene foam substrate using a hydrothermal method, and graphene foam electrodes loaded with noble metal nanoparticles are prepared by high-temperature pyrolysis. Uniformly distributed platinum nanoparticles are formed by a solvothermal method and pyrolysis steps. The multi-channel three-dimensional structure of the graphene foam is used to improve catalytic activity and stability.
It achieves high catalytic activity and excellent cycle stability of low-load noble metal electrodes. The graphene foam electrode has good flexibility and is suitable for harsh environments. The simple and quick preparation method is suitable for large-scale production.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of electrocatalytic hydrogen evolution, specifically to a graphene foam-based water electrolysis hydrogen evolution electrode and its preparation method. Background Technology
[0002] Hydrogen (H2), as a green and clean energy source, is widely considered an effective alternative to traditional fossil fuels. Hydrogen can be produced through many efficient strategies, such as fossil fuel refining, methane reforming, and photocatalytic water splitting. Among these, water electrolysis is generally considered one of the most promising and carbon-free strategies for H2 production. Typically, water electrolysis involves two half-reactions: the oxygen evolution reaction (OER) at the anolyte and the hydrogen evolution reaction (HER) at the catholyte. Both reactions require effective electrocatalysts to reduce the overpotential of the energy-consuming processes. With the rapid development of electrocatalysts, researchers have successfully developed many electrocatalysts with excellent catalytic performance, significantly improving the efficiency of hydrogen production from water electrolysis. However, traditional noble metal-based acidic / alkaline hydrogen production catalysts are too expensive and have relatively poor stability. Therefore, it is essential to develop electrodes or catalysts that are stable in acidic / alkaline media, inexpensive, readily available, and highly catalytically active.
[0003] Invention CN106048640A discloses a method for preparing an in-situ graphene-supported Pt electrocatalyst for hydrogen evolution on a graphite surface. After obtaining an in-situ graphene-supported graphite block through electrolysis, a Pt sheet electrode is used as the counter electrode via cyclic voltammetry electrodeposition. Pt dissolved from the anode Pt sheet electrode is deposited onto the surface of the graphene-supported graphite block at the cathode. The resulting electrode material exhibits excellent electrocatalytic hydrogen evolution activity and stability. Invention CN112481635A discloses a noble metal iridium hydrogen evolution electrocatalyst and its application. An iridium oxide-cobalt-based phosphate-carbon support composite material is formed on a carbon support via electrodeposition. This composite material exhibits a low iridium loading and demonstrates excellent electrochemical performance for hydrogen evolution (HER), comparable to that of commercial Pt / C catalysts. The aforementioned prior art methods all employ electrodeposition to load noble metals onto a carbon substrate surface, which suffers from drawbacks such as uneven surface loading, easy aggregation of noble metals, and difficulty in forming nanostructures.
[0004] Invention CN112892528A discloses a noble metal / carbon nanoparticle composite catalyst, its preparation method, and its application. It utilizes a dispersion of carbon material with oxygen-containing functional groups on its surface and a noble metal / ethylene glycol colloid. The reaction is carried out under heating conditions. Simultaneously, the oxygen-containing functional groups on the carbon material surface are reduced, achieving the bonding between the carbon matrix and the noble metal nanoparticles. This process removes the oxygen-containing functional groups from the ethylene glycol in the noble metal / ethylene glycol colloid and generates electrostatic bonds, promoting electron transfer and synergistic effects, resulting in highly efficient hydrogen production through water electrolysis. However, the electrostatic bonding between the carbon matrix and the noble metal nanoparticles is not entirely stable, and the prepared noble metal / carbon nanoparticle composite catalyst requires electrode modification before it can be put into operation. Summary of the Invention
[0005] This invention provides a graphene foam-based water electrolysis hydrogen evolution electrode and its preparation method. Noble metal ions are loaded onto a graphene foam substrate via a hydrothermal method, and the graphene foam electrode loaded with noble metal nanoparticles is obtained through high-temperature pyrolysis. The low-platinum-loaded graphene three-dimensional channel membrane electrode prepared by this method exhibits excellent catalytic performance, high conductivity, high activity, and excellent cycle stability.
[0006] The solution of the present invention to solve the above-mentioned technical problems is as follows: A method for preparing a hydrogen evolution electrode based on graphene foam water electrolysis, comprising the following steps:
[0007] 1) Take a graphene oxide film, heat it to a first temperature under a protective atmosphere and keep it at that temperature to obtain a carbonized film; heat the carbonized film to a second temperature and keep it at that temperature to obtain graphene foam;
[0008] 2) Graphene foam loaded with noble metal phase is prepared by immersing graphene foam in a noble metal solution and using a solvothermal method.
[0009] 3) The graphene foam loaded with noble metal phase is heated to the third temperature under a protective atmosphere and held to obtain the graphene foam electrode loaded with noble metal nanoparticles.
[0010] Preferably, in step 1), the carbon-to-oxygen ratio of the graphene oxide film is 1:2 to 4. The graphene oxide film can be prepared by methods such as doctor blade coating, vacuum filtration, rotary centrifugal spraying, and heating evaporation.
[0011] Preferably, in step 1), the first temperature is 800~2000℃, the holding time is 0.5~6 h, and the heating rate is 1~20 ℃ / min.
[0012] Preferably, in step 1), the second temperature is 2000~3200℃, the holding time is 0.5~6 h, and the heating rate is 1~20 ℃ / min.
[0013] Preferably, in step 2), the noble metal solution includes one or any combination of chloroplatinic acid solution, chloroauric acid solution, chloropalladium acid solution, iridium chloride solution, and ruthenium trichloride solution. The noble metal loaded on the obtained graphene foam includes one or any combination of Pt, Pd, Au, Ru, and Ir.
[0014] Preferably, in step 2), the solvent used in the solvothermal method is a mixture of ultrapure water and an organic solvent, wherein the volume ratio of ultrapure water to organic solvent is 1:4~8. Using a solvent of water and organic solvent in a certain proportion in the solvothermal method is more conducive to the dispersion of the metal salt solution and the formation of nanoparticles.
[0015] Preferably, the organic solvent is one or any combination of ethanol, ethylene glycol, methanol, isopropanol, and N,N-dimethylformamide.
[0016] Preferably, in step 2), the solvothermal reaction temperature is 80~220 ℃ and the holding time is 0.5~8 h.
[0017] Preferably, in step 3), the third temperature is 200~600 ℃, the heating rate is 1~20 ℃ / min, and the holding time is 1~4 h.
[0018] A graphene foam electrolysis hydrogen evolution electrode prepared according to the above method, the electrode comprising graphene foam, wherein platinum nanoparticles are uniformly loaded inside and outside the graphene foam, and the loading amount of platinum nanoparticles is 3.2~92 μg / cm³. -2 The electrical conductivity of graphene foam is 3000~50000 S / m, and the thickness of graphene foam is 10~2000 μm.
[0019] Preferably, the platinum nanoparticle loading in the electrode is 3~10 μg / cm³. -2 The electrical conductivity of graphene foam is 5000~45000 S / m, and the thickness of graphene foam is 50~500 μm.
[0020] More preferably, the platinum nanoparticle loading in the electrode is 6.2 μg / cm³. -2 The graphene foam has an electrical conductivity of 45,000 S / m and a thickness of 300 μm.
[0021] The beneficial effects of this invention are:
[0022] 1. The graphene foam electrode loaded with platinum nanoparticles provided by this invention uses graphene foam as a substrate. Compared with existing carbon substrates, graphene foam is soft and lightweight, making it easy to carry and bend in harsh environments, meeting the needs of industrial use. Graphene foam has ultra-high electrical conductivity, which has an important impact on improving the catalytic activity of the electrode. Graphene foam has a multi-channel three-dimensional pleated structure. This structure serves as a support point for Pt nanoparticles, making it less prone to agglomeration and easier to form nanostructures.
[0023] 2. This invention utilizes graphene foam to form a strong interaction with platinum active species under solvothermal conditions, which allows Pt nanoparticles to firmly adhere to its inner and outer surfaces, enabling the electrode to exhibit good catalytic performance and excellent stability in different acidic and alkaline media. The preparation method of this invention is simpler, faster, easier to operate, and more environmentally friendly, thereby realizing the controllable large-scale preparation of macroscopic electrodes.
[0024] 3. The graphene foam electrode loaded with platinum nanoparticles provided by this invention can be directly put into the electrolysis of water to produce hydrogen without any other modification steps.
[0025] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description
[0026] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:
[0027] Figure 1 This is a SEM image of the graphene foam prepared in Example 1 of the present invention;
[0028] Figure 2 The XRD pattern of the graphene foam electrode loaded with platinum nanoparticles prepared in Example 2 of this invention;
[0029] Figure 3 This is a SEM image of the graphene foam electrode loaded with platinum nanoparticles prepared in Example 2 of the present invention.
[0030] Figure 4 This is a SEM image of a cross-section of the graphene foam electrode loaded with platinum nanoparticles prepared in Example 2 of the present invention.
[0031] Figure 5 This is a SEM-mapping image of the graphene foam electrode loaded with platinum nanoparticles prepared in Example 2 of the present invention.
[0032] Figure 6 Linear scan voltammetry curves of the electrodes prepared in Comparative Example 1 and Example 2 of this invention;
[0033] Figure 7 This is a time-current curve of the long-term stability of the electrodes prepared in Comparative Example 1 and Example 2 of the present invention. Implementation
[0034] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.
[0035] The working principle of this invention is as follows: During the high-temperature graphitization process, graphene foam can not only form a multi-channel three-dimensional wrinkled structure, but also increase the conductivity of the substrate by orders of magnitude, thereby enhancing catalytic activity. Furthermore, compared to general carbon substrates, graphene foam is flexible and can be bent in harsh testing environments. The multi-channel three-dimensional wrinkled structure allows platinum nanoparticles to be uniformly loaded inside and outside the substrate, providing more active sites even with a low platinum loading, further improving the catalytic activity of the electrode. The preparation process uses a hydrothermal method to initially load platinum onto the graphene foam, rather than an in-situ method for loading active species. This solves the problem of uneven dispersion of the precursor graphene oxide during the mixing of the metal salt solution in existing technologies, enabling large-scale preparation of graphene foam electrodes. Example 1
[0036] The method for preparing the graphene foam electrode loaded with platinum nanoparticles described in this embodiment includes the following steps:
[0037] S1. A 20 mg / ml aqueous dispersion of graphene oxide was coated onto a Pet substrate using a doctor blade. The mixture was dried in a vacuum drying oven at 120 °C for 12 h. The resulting graphene oxide film was placed in a tube furnace and heated to 1300 °C at a heating rate of 5 °C / min under an argon atmosphere, and held for 2 h. The resulting carbonized film was then placed in a graphitization furnace and heated to 2850 °C at a heating rate of 2 °C / min, and held for 1 h to obtain graphene foam.
[0038] S2. The graphene foam was ultrasonically treated in a 0.2 mg / mL chloroplatinic acid solution for 0.5 h, and then the treated graphene foam was heat-treated at 180 °C for 1 h in a closed reaction vessel filled with a mixed solvent (N,N-dimethylformamide: ethanol: water = 5:1:1) to obtain graphene foam loaded with platinum species.
[0039] S3. Place the graphene foam electrode loaded with platinum species in a tube furnace and heat it to 300 ℃ in an inert gas at a rate of 2 ℃ / min for pyrolysis reduction. Hold the temperature for 2 h to obtain the graphene foam electrode loaded with platinum nanoparticles.
[0040] The graphene foam prepared in step 1) was characterized by its morphology, and the scanning electron microscope images are shown below. Figure 1 As shown, it can be observed that it has a multi-layered porous three-dimensional channel structure.
[0041] The conductivity of the graphene foam prepared in step 1) was tested using the four-probe method and found to be 5000 S / m.
[0042] The graphene foam electrode loaded with platinum nanoparticles obtained from the above reaction was subjected to electrochemical performance testing in a three-electrode system. The results showed that the graphene foam electrode loaded with platinum nanoparticles performed well at 10 mA cm⁻¹. -2 The overpotential value is 35 mV.
[0043] ICP elemental analysis revealed that the platinum content in the graphene foam electrode loaded with platinum nanoparticles obtained from the above reaction was 3.1 μg / cm³. -2 . Example 2
[0044] The method for preparing the graphene foam electrode loaded with platinum nanoparticles described in this embodiment includes the following steps:
[0045] S1. A 20 mg / ml aqueous dispersion of graphene oxide was coated onto a Pet substrate using a doctor blade. The mixture was dried in a vacuum drying oven at 120 °C for 12 h. The resulting graphene oxide film was placed in a tube furnace and heated to 1600 °C at a heating rate of 5 °C / min under an argon atmosphere, and held at that temperature for 2 h. The resulting carbonized film was then placed in a graphitization furnace and heated to 2850 °C at a heating rate of 2 °C / min, and held at that temperature for 1.5 h to obtain graphene foam.
[0046] S2. The graphene foam was ultrasonically treated in a 0.2 mg / mL chloroplatinic acid solution for 0.5 h, and then the treated graphene foam was heat-treated at 180 °C for 1 h in a closed reaction vessel filled with a mixed solvent (N,N-dimethylformamide: ethanol: water = 5:1:1) to obtain graphene foam loaded with platinum species.
[0047] S3. Platinum-loaded graphene foam electrode is placed in a tube furnace and heated to 350 °C at a rate of 2 °C / min in an inert gas atmosphere. The temperature is held for 2 h to perform pyrolysis reduction and obtain platinum-loaded graphene foam electrode.
[0048] The conductivity of the graphene foam prepared in step 1) was tested using the four-probe method and found to be 45,000 S / m.
[0049] The graphene foam electrode loaded with platinum nanoparticles obtained from the above reaction was subjected to electrochemical performance testing in a three-electrode system. The results showed that the graphene foam electrode loaded with platinum nanoparticles performed well at 10 mA cm⁻¹. -2 The overpotential value is 28 mV.
[0050] The XRD pattern of the graphene foam electrode loaded with platinum nanoparticles obtained from the above reaction is shown below. Figure 2 As shown, X-ray diffraction peaks of the metallic element platinum can be observed, corresponding to the (111) and (200) crystal planes of platinum.
[0051] The graphene foam electrode loaded with platinum nanoparticles obtained from the above reaction was characterized by its morphology, and the scanning electron microscope image of the electrode surface is shown below. Figure 3 As shown, the scanning electron microscope image of its electrode cross-section is as follows: Figure 4 The figure shows the platinum element distribution of the graphene foam electrode containing platinum nanoparticles, as measured by SEM-mapping. Figure 5 As shown, platinum nanoparticles can be observed uniformly loaded inside and outside the graphene foam.
[0052] ICP elemental analysis revealed that the platinum content in the graphene foam electrode loaded with platinum nanoparticles was 6.2 μg / cm³. -2 . Example 3
[0053] The method for preparing the graphene foam electrode loaded with platinum nanoparticles described in this embodiment includes the following steps:
[0054] S1. A 20 mg / ml aqueous dispersion of graphene oxide was coated onto a Pet substrate using a doctor blade. The mixture was dried in a vacuum drying oven at 120 °C for 12 h. The resulting graphene oxide film was placed in a tube furnace and heated to 2200 °C at a heating rate of 5 °C / min under an argon atmosphere, and held at that temperature for 2 h. The resulting carbonized film was then placed in a graphitization furnace and heated to 2850 °C at a heating rate of 2 °C / min, and held at that temperature for 2 h to obtain graphene foam.
[0055] S1. A 20 mg / ml aqueous dispersion of graphene oxide was coated onto a Pet substrate using a doctor blade. The mixture was dried in a vacuum drying oven at 120 °C for 12 h. The resulting graphene oxide film was placed in a tube furnace and heated to 1600 °C at a heating rate of 5 °C / min under an argon atmosphere, and held at that temperature for 2 h. The resulting carbonized film was then placed in a graphitization furnace and heated to 2850 °C at a heating rate of 2 °C / min, and held at that temperature for 1.5 h to obtain graphene foam.
[0056] S3. Platinum-loaded graphene foam electrode is placed in a tube furnace and heated to 400 ℃ at a rate of 5 ℃ / min in an inert gas atmosphere. The temperature is held for 2 h to perform pyrolysis reduction and obtain platinum-loaded graphene foam electrode.
[0057] The conductivity of the graphene foam prepared in step 1) was tested using the four-probe method and found to be 17000 S / m.
[0058] S4. The graphene foam electrode loaded with platinum nanoparticles obtained from the above reaction was subjected to electrochemical performance testing in a three-electrode system. The results showed that the graphene foam electrode loaded with platinum nanoparticles performed well at 10 mA cm⁻¹. -2 The overpotential value is 48 mV.
[0059] ICP elemental analysis revealed that the platinum content of the graphene foam electrode loaded with platinum nanoparticles obtained from the above reaction was 28 μg / cm³. -2 . Example 4
[0060] The method for preparing the graphene foam electrode loaded with platinum nanoparticles described in this embodiment includes the following steps:
[0061] S1. A 20 mg / ml aqueous dispersion of graphene oxide was coated onto a Pet substrate using a doctor blade. The mixture was dried in a vacuum drying oven at 120 °C for 12 h. The resulting graphene oxide film was placed in a tube furnace and heated to 2200 °C at a heating rate of 5 °C / min under an argon atmosphere, and held for 1 h. The resulting carbonized film was then placed in a graphitization furnace and heated to 2850 °C at a heating rate of 2 °C / min, and held for 2 h to obtain graphene foam.
[0062] S2. The graphene foam was ultrasonically treated in a 0.3 mg / mL chloroplatinic acid solution for 0.5 h, and then the treated graphene foam was heat-treated at 200 °C for 2 h in a closed reaction vessel filled with a mixed solvent (N,N-dimethylformamide: ethanol: water = 5:1:1) to obtain graphene foam loaded with platinum species.
[0063] S3. Platinum-loaded graphene foam electrode is placed in a tube furnace and heated to 450 °C at a rate of 2 °C / min in an inert gas atmosphere. The temperature is held for 2 h to perform pyrolysis reduction and obtain platinum-loaded graphene foam electrode.
[0064] The conductivity of the graphene foam prepared in step 1) was tested using the four-probe method and found to be 26000 S / m.
[0065] The graphene foam electrode loaded with platinum nanoparticles obtained from the above reaction was subjected to electrochemical performance testing in a three-electrode system. The results showed that the graphene foam electrode loaded with platinum nanoparticles performed well at 10 mA cm⁻¹. -2 The overpotential value is 58 mV.
[0066] ICP elemental analysis revealed that the platinum content of the graphene foam electrode loaded with platinum nanoparticles obtained from the above reaction was 55 μg / cm³. -2 .
[0067] Comparative Example 1
[0068] Carbon paper was immersed in a 0.3 mg / mL chloroplatinic acid solution and sonicated for 0.5 h. Then, it was placed in a sealed reactor filled with a mixed solvent (N,N-dimethylformamide: ethanol: water = 5:1:1) and heat-treated at 200 °C for 2 h to load Pt active species. The carbon paper loaded with Pt active species was then thermally reduced in a tube furnace to obtain a carbon paper electrode loaded with Pt nanoparticles.
[0069] The carbon paper electrode (denoted as Pt / CP) loaded with platinum nanoparticles obtained from the above reaction was subjected to electrochemical performance testing in a three-electrode system. The results showed that the graphene foam electrode loaded with platinum nanoparticles performed well at 10 mA cm⁻¹. -2 The overpotential value is 126 mV. Its linear sweep voltammetry curve is compared with that of the electrode prepared in Example 2 (denoted as Pt / GO-2850), as shown below. Figure 6 As shown, the multi-channel three-dimensional pleated structure of graphene foam is more conducive to the adsorption of Pt nanoparticles and increases the number of active sites.
[0070] The stability of the carbon paper electrode loaded with platinum nanoparticles (denoted as Pt / CP) and the electrode prepared in Example 2 (denoted as Pt / GO-2850) was tested in 1 M KOH electrolyte. Figure 7 As shown, the graphene foam electrode loaded with platinum nanoparticles can remain stable for 300 hours, demonstrating excellent long-term stability.
[0071] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.
Claims
1. A method for preparing a hydrogen evolution electrode based on graphene foam water electrolysis, characterized in that, Includes the following steps: 1) Take a graphene oxide film, heat it to a first temperature under a protective atmosphere and keep it at that temperature to obtain a carbonized film; heat the carbonized film to a second temperature and keep it at that temperature to obtain graphene foam; 2) Graphene foam loaded with noble metal phase was prepared by immersing graphene foam in chloroplatinic acid solution and using a solvothermal method; the solvothermal reaction temperature was 80~220 ℃ and the holding time was 0.5~8 h. 3) Graphene foam loaded with noble metal phase is heated to 200-600 ℃ at a heating rate of 1-20 ℃ / min under a protective atmosphere and held for 1-4 h to obtain graphene foam electrode loaded with noble metal nanoparticles.
2. The method for preparing a graphene foam-based water electrolysis hydrogen evolution electrode according to claim 1, characterized in that, In step 1), the carbon-to-oxygen ratio of the graphene oxide film is 1:2~4.
3. The method for preparing a graphene foam-based water electrolysis hydrogen evolution electrode according to claim 1, characterized in that, In step 1), the first temperature is 800~2000℃, the holding time is 0.5~6 h, and the heating rate is 1~20 ℃ / min.
4. The method for preparing a graphene foam-based water electrolysis hydrogen evolution electrode according to claim 1, characterized in that, In step 1), the second temperature is 2000~3200℃, the holding time is 0.5~6 h, and the heating rate is 1~20 ℃ / min.
5. The method for preparing a graphene foam-based water electrolysis hydrogen evolution electrode according to claim 1, characterized in that, In step 2), the solvent used in the solvothermal method is a mixture of ultrapure water and organic solvent, wherein the volume ratio of ultrapure water to organic solvent is 1:4~8.
6. The method for preparing a graphene foam-based water electrolysis hydrogen evolution electrode according to claim 5, characterized in that, The organic solvent is one or any combination of ethanol, ethylene glycol, methanol, isopropanol, and N,N-dimethylformamide.
7. A graphene foam electrolysis hydrogen evolution electrode prepared according to any one of claims 1-6, characterized in that, The electrode comprises graphene foam, on the inside and outside of which platinum nanoparticles are uniformly loaded, with a platinum nanoparticle loading of 3.2~92 μg / cm³. -2 The electrical conductivity of graphene foam is 3000~50000 S / m, and the thickness of graphene foam is 10~2000 μm.