A preparation method of HER / HOR bifunctional electrocatalyst for electrochemical hydrogen pump

Abstract

This invention discloses a method for preparing a HER / HOR bifunctional electrocatalyst for electrochemical hydrogen pumps, belonging to the field of new energy materials technology. This invention designs and synthesizes a molybdenum carbide support with a porous nanoflower structure to provide anchoring for platinum-ruthenium electroloading. The catalyst can be used to improve the acidic HER / HOR performance of the platinum-ruthenium electrocatalyst. This invention investigates the effect of platinum-ruthenium content on acidic HER / HOR performance, finding that the Pt / Ru@Mo2C catalyst exhibits the best acidic HER / HOR performance and the best CO anti-poisoning effect when the platinum-ruthenium content ratio is 1:1. System structural characterization and electrochemical hydrogen evolution and hydrogen oxidation performance tests show that the Pt / Ru@Mo2C catalyst achieves acidic HER performance at 10 mA cm⁻¹. ‑2 At the specified current density, its overpotential is 13 mV; the acidic HOR performance achieves a current density of 3.02 mA cm⁻¹ at 50 mV. ‑2 The electrocatalytic performance of the HER / HOR catalyst is comparable to that of the 20 wt.% Pt / C catalyst, while its CO anti-poisoning effect is far superior. This work provides a new approach for developing efficient and stable acidic HER / HOR bifunctional catalysts, and promotes the development of proton exchange membrane water electrolysis, hydrogen fuel cells, and electrochemical hydrogen pump technologies.

Description

[0001] This invention belongs to the field of new materials technology, specifically relating to a method for preparing a HER / HOR bifunctional electrocatalyst for electrochemical hydrogen pumps. Background Technology

[0002] With increasingly severe energy and environmental problems, people in modern society are paying more and more attention to the environment. Protecting the environment and achieving sustainable development are common goals for all mankind. As a result, people's desire for efficient and clean energy is growing, and the development of new energy sources has received increasing attention in recent years. Since the beginning of the Industrial Revolution in the 18th century, fossil fuels, mainly coal, oil, and natural gas, have provided the driving force for the world economy. However, with the significant increase in the total energy consumption of humankind and the gradual depletion of non-renewable fossil fuels, our environment is under great threat, and energy supply is becoming increasingly strained. Finding alternatives to fossil fuels is the most urgent goal for people in the coming decades.

[0003] Hydrogen energy, with its high energy density and zero carbon emissions, is becoming a core carrier for the global energy system's transition to cleaner and lower-carbon energy. In particular, the maturity of polymer electrolyte membrane technology has created a highly efficient closed-loop energy cycle, with proton exchange membrane water electrolysis (PEMWE) for hydrogen production and proton exchange membrane fuel cells (PEMFC) for power generation. This closed loop not only achieves bidirectional conversion between green electricity and hydrogen energy but also breaks down the physical boundaries of traditional energy storage and transportation through the coupling effect of an electrochemical hydrogen pump. The hydrogen pump enables precise directional control of hydrogen under different chemical potentials and pressures, becoming the core link between the PEMWE and PEMFC systems. This integrated energy system demonstrates irreplaceable strategic value in the low-altitude economy and special operations: from power line inspection and agricultural and forestry protection to disaster relief and marine mapping, hydrogen drones, with their long endurance and rapid refueling capabilities, are becoming key equipment for overcoming grid coverage limitations and activating new business application scenarios.

[0004] Despite its promising prospects, the large-scale implementation of the hydrogen energy industry still faces bottlenecks, restricting its application breadth and technological depth. The widespread use of mobile equipment such as hydrogen drones heavily relies on mobile, highly integrated, renewable energy-driven on-site hydrogen production and pressurization equipment. Traditional high-pressure gaseous hydrogen storage technology is not only costly and raises concerns about storage and transportation safety, but also heavily depends on fixed hydrogen refueling station infrastructure, failing to cover operating areas with weak power grids or remote locations. This bottleneck directly limits the expansion of the low-altitude economy, becoming a key obstacle for hydrogen energy technology to move from the laboratory to the broader market.

[0005] The core efficiency of hydrogen energy technology depends on the efficiency of electrochemical reactions. The hydrogen evolution reaction (HER) and the hydrogen oxidation reaction (HOR), as two fundamental processes in hydrogen production and utilization, directly determine the overall energy conversion efficiency of the system through their kinetic rates. However, after decades of research, developing bifunctional HOR / HER catalytic materials that simultaneously possess high activity, high stability, and low cost remains a major challenge for the scientific community. The current understanding of the reaction mechanisms at the atomic level in catalytic systems is still incomplete, which severely hinders the iterative upgrades of high-performance electrochemical hydrogen pumps and hydrogen energy systems.

[0006] Faced with the aforementioned challenges, the key to breakthroughs lies in returning to electrocatalytic materials for energy conversion. Solving the kinetic sluggishness of the hydrogen evolution reaction (HER) and hydrogen oxidation reaction (HOR) is the fundamental path to improving the efficiency of the entire hydrogen energy system and reducing application costs. Therefore, this invention focuses on the targeted design and controllable preparation of high-performance electrocatalytic materials. By deeply analyzing the structure-activity relationship of catalytic active centers at the atomic and electronic levels, and precisely controlling the crystal structure, electronic states, and interface effects of the materials, a series of novel catalyst materials with both high HER / HOR dual-functional activity and excellent stability have been developed. By constructing efficient and stable catalytic systems, not only can a powerful core be provided for electrochemical hydrogen pumps, breaking through the technical barriers of off-grid hydrogen production and pressurization, but core technological support can also be provided for the entire hydrogen energy industry chain, accelerating the efficient conversion and utilization of renewable energy, ultimately promoting the achievement of the "dual-carbon" strategic goal and unleashing the enormous potential of the hydrogen energy industry. Summary of the Invention

[0007] The purpose of this invention is to provide a method for preparing a HER / HOR bifunctional electrocatalyst for electrochemical hydrogen pumps. This method designs and synthesizes a molybdenum carbide support with a porous nanoflower structure to enhance the acidic HER / HOR performance of a platinum-ruthenium electrocatalyst. This invention investigates the effect of platinum-ruthenium content on the acidic HER / HOR performance, finding that a platinum-ruthenium content ratio of 1:1 results in the Pt / Ru@Mo2C catalyst exhibiting the best acidic HER / HOR performance and the best CO anti-poisoning effect. System structural characterization and electrochemical hydrogen evolution and hydrogen oxidation performance tests show that the Pt / Ru@Mo2C catalyst achieves acidic HER performance at 10 mA cm⁻¹. -2 At the specified current density, its overpotential is 13 mV; the acidic HOR performance achieves a current density of 3.02 mA cm⁻¹ at 50 mV. -2 Its performance is comparable to that of the 20 wt.% Pt / C catalyst, and its CO poisoning resistance is far superior to that of the 20 wt.% Pt / C catalyst. This work provides a new approach for developing highly efficient and stable acidic HER / HOR bifunctional catalysts.

[0008] To achieve the above objectives, the present invention provides the following solution:

[0009] One of the technical solutions of the present invention is to provide a molybdenum carbide-supported platinum-ruthenium acidic HER / HOR bifunctional catalyst, wherein the supported electrocatalyst comprises a conductive support with a high specific surface area and a reduced-modified metal nanoparticle material supported on the conductive support.

[0010] Furthermore, the conductive carrier is molybdenum carbide;

[0011] Furthermore, the molybdenum carbide support used in this invention has a high specific surface area;

[0012] Furthermore, the morphology of the molybdenum carbide conductive carrier is a nano-flower-like structure;

[0013] Furthermore, the reduction method is sodium borohydride reduction;

[0014] Furthermore, the metal nanomaterial is Pt or Ru.

[0015] The second technical solution of this invention: provides an acidic HER / HOR bifunctional catalyst supported on molybdenum carbide and platinum-ruthenium, and its preparation method, comprising the following steps:

[0016] An acidic HER / HOR bifunctional catalyst supported on molybdenum carbide and potassium chloroplatinate and ruthenium trichloride was designed and synthesized. Electrocatalysts with different metal atomic-level doping were obtained after metal loading and reduction. The structure composition of the catalysts and the structure-activity relationship of their electrocatalytic hydrogen evolution performance and hydrogen oxidation performance were then systematically studied.

[0017] The synthesis of the catalyst (Pt / Ru@Mo2C) includes the following steps:

[0018] The synthesized Mo7-PDA was placed in a tube furnace and kept at 450℃ for 2 h and 800℃ for 3 h under an Ar atmosphere to obtain Mo2C nanoflower carrier with high specific surface area.

[0019] A metal material solution was added to the carrier solution and stirred to obtain a mixed solution. Sodium borohydride solution was added for reduction, and the solution was filtered and dried to obtain molybdenum carbide-supported platinum-ruthenium metal material.

[0020] Furthermore, the concentration of the sodium borohydride solution is 0.03 M;

[0021] Furthermore, the mass ratio of the loaded metal nanoparticles, platinum to ruthenium, is 1:1;

[0022] Furthermore, the metal nanomaterial includes potassium chloroplatinate and / or ruthenium trichloride;

[0023] Furthermore, the drying process is vacuum drying.

[0024] Addressing the issues of easy aggregation, poor binding force, and poor hydrophilicity inherent in metal nanoparticles, this invention utilizes a high specific surface area carrier to inhibit aggregation, stabilize dispersion, and increase the active specific surface area of ​​metal nanoparticles. Simultaneously, during the formation of molybdenum carbide-supported metal nanoparticles, the metal nanoparticles provide active sites. The high specific surface area of ​​the molybdenum carbide nanospheres provides anchoring points for the loading of metal nanoparticles, allowing for the control of nanoparticle size and the acquisition of different quantum effects, thus achieving stable high-metal-quality activity. Furthermore, the molybdenum carbide carrier enables the formation of a highly negatively charged shell on the surface of the metal particles, significantly inhibiting aggregation under storage, catalytic, and harsh conditions.

[0025] The third technical solution of this invention:

[0026] A controllable synthesis method for Pt-Ru-Mo ternary catalysts was established. Through processes such as high-temperature carbonization and direct adsorption, atomic-level dispersion and strong interfacial coupling of metals on Mo2C support were achieved, and a uniform nanostructure with abundant active sites was constructed.

[0027] Furthermore, the Pt source serves to provide electrocatalytic active sites;

[0028] Furthermore, the Ru source function is to provide oxygen species at a lower potential to oxidize and remove CO adsorbed on adjacent Pt sites;

[0029] Furthermore, the role of the Mo source is to provide electrons, which can shift the d-band center of Pt and Ru downward and optimize the hydrogen adsorption free energy.

[0030] Furthermore, the high-temperature carbonization method involves placing the obtained Mo7-PDA in a tube furnace and heating it at 450°C for 2 hours under an argon atmosphere, followed by heating it at 800°C for 3 hours.

[0031] Furthermore, the direct adsorption method involves directly adsorbing potassium chloroplatinate and ruthenium trichloride onto the Mo2C support.

[0032] The fourth technical solution of the present invention provides an application of the above-mentioned metal nanoparticles anchored on molybdenum carbide nanoflowers as an electrode modification material in the preparation of electrocatalytic reaction electrodes.

[0033] Furthermore, the electrocatalytic reaction includes water electrolysis to produce hydrogen and electrocatalytic hydrogen oxidation.

[0034] Fifth technical solution of the present invention: Provides an electrode for hydrogen production by water electrolysis and electrocatalytic hydrogenation, wherein the active component of the electrode includes a supported catalyst anchored on molybdenum carbide nanospheres as described above.

[0035] The sixth technical solution of the present invention provides a method for producing hydrogen by electrolysis of water and electrocatalytic hydrogenation, wherein the above-mentioned electrode is used as the working electrode.

[0036] The seventh technical solution of this invention provides an acidic HER / HOR bifunctional catalyst that can be used in proton exchange membrane water electrolysis, fuel cells, and electrochemical hydrogen pumps.

[0037] The present invention discloses the following technical effects:

[0038] The supported catalyst prepared by this invention, with metal nanoparticles anchored on molybdenum carbide nanoflowers, exhibits strong performance in water electrolysis for hydrogen production and electrocatalytic hydrogenation, and has great potential for electrocatalytic applications.

[0039] This invention provides a novel strategy for synthesizing high-performance acidic HER / HOR catalyst materials, with the following outstanding advantages: ① A Pt-Ru-Mo ternary metal synergistic system was designed and constructed. By controlling the electronic structure and geometric effects between different metal elements, the active sites on the catalyst surface were precisely constructed and optimized, significantly enhancing reaction kinetics; ② The synergistic mechanism and CO-resistant nature of the Pt-Ru-Mo ternary system were elucidated. Advanced characterization and theoretical calculations were comprehensively applied to reveal the intermetallic electron transfer rules and the HER / HOR bifunctional catalytic mechanism, explaining the structural origin of its high activity, high stability, and high CO tolerance at the atomic level; ③ The designed catalyst can be applied to proton exchange membrane water electrolysis, hydrogen fuel cells, and electrochemical hydrogen pump technology; ④ The synthesis process is simple, efficient, and controllable, enabling large-scale synthesis and providing significant possibilities for practical production. This invention starts with the design of Mo2C supports with different Pt and Ru contents. By designing the combination mode of Pt, Ru, and Mo2C supports and optimizing conditions such as Pt and Ru loading, a highly efficient HER / HOR bifunctional Pt / Ru@Mo2C catalyst is prepared. This research aims to precisely design and control the loading of Pt and Ru, as well as the Mo substrate, by adjusting the amounts of Pt and Ru source, sodium borohydride, and temperature. This allows for the regulation of the electrocatalytic HER / HOR performance. Furthermore, characterization techniques such as XRD and SEM are used to investigate the structure-activity relationship and catalytic reaction mechanism of the Pt / Ru@Mo2C electrocatalyst, providing feedback guidance for catalyst synthesis. The goal is to obtain an acidic HER / HOR bifunctional electrocatalyst with both high activity and high stability, offering a solution to the current bottlenecks in the development of proton exchange membrane water electrolysis, hydrogen fuel cells, and electrochemical hydrogen pumps. Attached Figure Description

[0040] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0041] Figure 1These are transmission electron microscope (TEM) images obtained using a metal load on Mo2C (Pt / Ru@Mo2C) according to an embodiment of the present invention;

[0042] Figure 2 These are scanning electron microscope (SEM) images obtained using Pt / Ru@Mo2C according to embodiments of the present invention;

[0043] Figure 3 These are high-resolution transmission electron microscope (HRTEM) images obtained using Pt / Ru@Mo2C according to embodiments of the present invention;

[0044] Figure 4 These are X-ray energy dispersive spectroscopy images obtained using Pt / Ru@Mo2C according to embodiments of the present invention;

[0045] Figure 5 These are XRD spectra and JCPDS standard spectra obtained using Pt / Ru@Mo2C, Pt@Mo2C and Ru@Mo2C according to embodiments and comparative examples of the present invention;

[0046] Figure 6 Raman spectra obtained using Pt / Ru@Mo2C, Pt@Mo2C, and Ru@Mo2C according to embodiments and comparative examples of the present invention;

[0047] Figure 7 This is a comparative performance graph of electrocatalytic hydrogen evolution obtained using Pt / Ru@Mo2C, Pt@Mo2C, Ru@Mo2C and 20 wt.% Pt / C in the embodiments and comparative examples of the present invention;

[0048] Figure 8 This is a comparative performance graph of electrocatalytic hydrogenation obtained using Pt / Ru@Mo2C, Pt@Mo2C, Ru@Mo2C and 20 wt.%Pt / C according to embodiments and comparative examples of the present invention;

[0049] Figure 9 This is a comparison graph of CO resistance performance obtained using Pt / Ru@Mo2C, Pt@Mo2C, Ru@Mo2C and 20 wt.% Pt / C in the embodiments and comparative examples of the present invention;

[0050] Figure 10 This is a stability diagram of the proton exchange membrane water electrolysis hydrogen production technology obtained using Pt / Ru@Mo2C according to an embodiment of the present invention.

[0051] Figure 11 This is a flowchart of the synthesis process using Pt / Ru@Mo2C according to an embodiment of the present invention. Detailed Implementation

[0052] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0053] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0054] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0055] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0056] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0057] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0058] In the specific embodiments of the present invention, the room temperature and ambient temperature are both 20-30℃.

[0059] The raw materials and reagents used in the specific embodiments of this invention are all commercially available products.

[0060] It should be noted that the carriers used in the specific embodiments of the present invention can be commercially available or self-made, without affecting the realization of the technical effect.

[0061] Example

[0062] (1) Synthesis of Mo7-PDA: Weigh 0.27 g of ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O24 Dissolve 0.27 g of dopamine hydrochloride (C8H4H2O, Mo7) in 72 mL of deionized water. 12 Dissolve ClNO2 (PDA) in 144 mL of anhydrous ethanol and stir until dissolved. After both reactants are completely dissolved, add dopamine hydrochloride to ammonium heptamolybdate tetrahydrate and stir for 10 min. Add 1.10 mL of ammonia water to adjust the pH. Stir for 6 h, centrifuge directly (8500 rpm, 5 min), and wash three times with anhydrous ethanol. Place in a forced-air drying oven and dry overnight at 80 °C to obtain Mo7-PDA.

[0063] (2) Preparation of Mo2C substrate: The Mo7-PDA obtained in (1) was placed in a tube furnace and kept at 450℃ for 2 h and at 800℃ for 3 h to obtain a porous nanoflower ball Mo2C substrate.

[0064] (3) Adsorption of Pt / Ru: 50 mg of Mo2C nanoflora balls were weighed as a substrate and placed in an ultrasonic machine to be ultrasonically dispersed in 15 ml of deionized water. Then, 12.46 mg of potassium chloroplatinate and 10.26 mg of ruthenium trichloride were weighed and ultrasonically dissolved in 15 ml of deionized water, respectively. The completely dissolved potassium chloroplatinate and ruthenium trichloride were added to the Mo2C substrate one after another and stirred for 20 min.

[0065] (4) Preparation of Pt / Ru@Mo2C catalyst: Add 16 ml of 0.3 M sodium borohydride solution to the mixed solution obtained in the previous step, stir for 30 min, filter the solution, and place the obtained solid product in a vacuum drying oven. The Pt / Ru@Mo2C catalyst is obtained.

[0066] (5) Preparation of electrocatalytic HER / HOR electrode: Weigh 5 mg of Pt / Ru@Mo2C catalyst and grind it evenly in an agate mortar. Add a mixed dispersant of ethanol and Nafion solution, and sonicate to form a uniform dispersion. Then, heat the dispersion at 0.1963 cm⁻¹. 2 15 μL of the above solution was uniformly drop-coated onto a glassy carbon electrode and dried to form an electrode sheet.

[0067] (6) To characterize the electrocatalytic hydrogen evolution and electrocatalytic hydrogen oxidation performance of the prepared electrode materials, a three-electrode system was constructed using a DSR-M testing equipment from China National Chemical Engineering Co., Ltd. and a CHI760E electrochemical workstation from Shanghai Chenhua Co., Ltd. The HER / HOR performance of Pt / Ru@Mo2C was tested at room temperature. All electrochemical tests were conducted in a three-electrode system with a reversible hydrogen electrode as the reference electrode, a platinum wire as the counter electrode, the electrode prepared in step (5) as the working electrode, and 0.5 mol / L H2SO4 solution as the electrolyte solution.

[0068] in, Figure 1 The transmission electron microscope (TEM) images obtained using the Mo2C-supported platinum acetylacetone catalyst (Pt / Ru@Mo2C) in the examples show that the Mo2C-supported platinum metal particles are few, uniformly distributed, and do not agglomerate.

[0069] in, Figure 2 The scanning electron microscope (SEM) images obtained using Pt / Ru@Mo2C in the examples show that the synthesized catalysts maintain the original morphology of the Mo2C substrate. All catalysts have good nanoflower-like structures. This nanoflower-like structure with high specific surface area is conducive to exposing more catalytic sites, thereby improving intrinsic catalytic activity.

[0070] in, Figure 3 In the example, the lattice spacing was measured using a high-resolution transmission electron microscope (HRTEM) obtained from Pt / Ru@Mo2C. The measured lattice spacing was 0.228 nm, corresponding to the (102) crystal plane of Mo2C.

[0071] in, Figure 4 The transmission electron microscope X-ray energy dispersive spectroscopy images obtained using Pt / Ru@Mo2C in the embodiment show that C, N, O, Mo, Pt, and Ru elements are uniformly distributed, indicating that Pt and Ru species are uniformly loaded on the Mo2C substrate.

[0072] Comparative Example 1

[0073] (1) Synthesis of Mo7-PDA: Weigh 0.27 g of ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O 24 Dissolve 0.27 g of dopamine hydrochloride (C8H4H2O, Mo7) in 72 mL of deionized water. 12 Dissolve ClNO2 (PDA) in 144 mL of anhydrous ethanol and stir until dissolved. After both reactants are completely dissolved, add dopamine hydrochloride to ammonium heptamolybdate tetrahydrate and stir for 10 min. Add 1.10 mL of ammonia water to adjust the pH. Stir for 6 h, centrifuge directly (8500 rpm, 5 min), and wash three times with anhydrous ethanol. Place in a forced-air drying oven and dry overnight at 80 °C to obtain Mo7-PDA.

[0074] (2) Preparation of Mo2C substrate: The Mo7-PDA obtained in (1) was placed in a tube furnace and kept at 450℃ for 2 h and at 800℃ for 3 h to obtain a porous nanoflower ball Mo2C substrate.

[0075] (3) Adsorption of Pt: Weigh 50 mg of Mo2C nanoflower balls as a substrate, place them in an ultrasonic machine, and ultrasonically disperse them in 15 ml of deionized water. Then, ultrasonically dissolve them in 15 ml of deionized water. Add the completely dissolved potassium chloroplatinate to the Mo2C substrate and stir for 20 min.

[0076] (4) Preparation of Pt@Mo2C catalyst: Add 8 ml of 0.3 M sodium borohydride solution to the mixed solution obtained in the previous step, stir for 30 min, filter the solution, and place the obtained solid product in a vacuum drying oven. Pt@Mo2C catalyst is obtained.

[0077] (5) Preparation of electrocatalytic HER / HOR electrode: Weigh 5 mg of Pt@Mo2C catalyst and grind it evenly in an agate mortar. Add a mixed dispersant of ethanol and Nafion solution, and sonicate to form a uniform dispersion. Then, heat the dispersion at 0.1963 cm⁻¹. 2 15 μL of the above solution was uniformly drop-coated onto a glassy carbon electrode and dried to form an electrode sheet.

[0078] (6) To characterize the electrocatalytic hydrogen evolution and electrocatalytic hydrogen oxidation performance of the prepared electrode materials, a three-electrode system was constructed using a DSR-M testing equipment from China National Chemical Engineering Co., Ltd. and a CHI760E electrochemical workstation from Shanghai Chenhua Co., Ltd. The HER / HOR performance of Pt@Mo2C was tested at room temperature. All electrochemical tests were conducted in a three-electrode system with a reversible hydrogen electrode as the reference electrode, a platinum wire as the counter electrode, the electrode prepared in step (5) as the working electrode, and 0.5 mol / L H2SO4 solution as the electrolyte solution.

[0079] Comparative Example 2

[0080] (1) Synthesis of Mo7-PDA: Weigh 0.27 g of ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O 24 Dissolve 0.27 g of dopamine hydrochloride (C8H4H2O, Mo7) in 72 mL of deionized water. 12 Dissolve ClNO2 (PDA) in 144 mL of anhydrous ethanol and stir until dissolved. After both reactants are completely dissolved, add dopamine hydrochloride to ammonium heptamolybdate tetrahydrate and stir for 10 min. Add 1.10 mL of ammonia water to adjust the pH. Stir for 6 h, centrifuge directly (8500 rpm, 5 min), and wash three times with anhydrous ethanol. Place in a forced-air drying oven and dry overnight at 80 °C to obtain Mo7-PDA.

[0081] (2) Preparation of Mo2C substrate: The Mo7-PDA obtained in (1) was placed in a tube furnace and kept at 450℃ for 2 h and at 800℃ for 3 h to obtain a porous nanoflower ball Mo2C substrate.

[0082] (3) Ru adsorption: Weigh 50 mg of Mo2C nanoflower balls as a substrate, place them in an ultrasonic machine, and ultrasonically disperse them in 15 ml of deionized water. Then, dissolve 10.26 mg of ruthenium trichloride in 15 ml of deionized water by ultrasonication. Add the completely dissolved ruthenium trichloride to the Mo2C substrate and stir for 20 min.

[0083] (4) Preparation of Ru@Mo2C catalyst: Add 8 ml of 0.3 M sodium borohydride solution to the mixed solution obtained in the previous step, stir for 30 min, filter the solution, and place the obtained solid product in a vacuum drying oven. The Ru@Mo2C catalyst is obtained.

[0084] (5) Preparation of electrocatalytic HER / HOR electrode: Weigh 5 mg of Ru@Mo2C catalyst and grind it evenly in an agate mortar. Add a mixed dispersant of ethanol and Nafion solution, and sonicate to form a uniform dispersion. Then, heat the dispersion at 0.1963 cm⁻¹. 2 15 μL of the above solution was uniformly drop-coated onto a glassy carbon electrode and dried to form an electrode sheet.

[0085] (6) To characterize the electrocatalytic hydrogen evolution and electrocatalytic hydrogen oxidation performance of the prepared electrode materials, a three-electrode system was constructed using a DSR-M testing device from China National Chemical Engineering Co., Ltd. and a CHI760E electrochemical workstation from Shanghai Chenhua Co., Ltd. The HER / HOR performance of Ru@Mo2C was tested at room temperature. All electrochemical tests were conducted in a three-electrode system with a reversible hydrogen electrode as the reference electrode, a platinum wire as the counter electrode, the electrode prepared in step (5) as the working electrode, and 0.5 mol / L H2SO4 solution as the electrolyte solution.

[0086] Test case

[0087] Weigh 5 mg of catalyst powder, add its deionized water (475 μL), isopropanol (475 μL) and Nafion membrane solution (50 μL), and sonicate to form a uniform dispersion. Then take 15 μL of the dispersion and coat it onto a glassy carbon electrode with a platinum loading of 0.75 mg cm⁻². After drying, the working electrode is obtained.

[0088] The electrocatalytic hydrogen evolution performance of the above working electrode was characterized by the following tests:

[0089] The HER / HOR performance of Pt / Ru@Mo2C, Pt@Mo2C, Ru@Mo2C, and 20 wt.% Pt / C was tested at room temperature using a three-electrode system built with a DSR-M testing equipment from China Physico-Chemical Co., Ltd. and a CHI760E electrochemical workstation from Shanghai Chenhua Co., Ltd. Electrochemical tests were conducted in a three-electrode system with a reversible hydrogen electrode as the reference electrode, a platinum wire as the counter electrode, the prepared electrode as the working electrode, and 0.5 mol / L H2SO4 solution as the electrolyte.

[0090] in, Figure 5 According to the XRD patterns and JCPDS standard patterns obtained using Pt / Ru@Mo2C, Pt@Mo2C, and Ru@Mo2C according to the embodiments and comparative examples of the present invention, the three samples all showed obvious characteristic diffraction peaks of Mo2C at 34.3°, 34.4°, 37.9°, 39.3°, 39.5°, 52.1°, 52.2°, 61.4°, 61.6°, 69.5°, 72.3°, 72.6°, 74.5°, and 74.7° (PDF card). #31-0871 corresponds to the (021), (002), (200), (121), (102), (221), (202), (040), (023), (321), (042), (004), and (240) crystal planes of Mo2C, respectively, indicating the presence of the Mo2C phase in the material and proving the successful synthesis of the hexagonal Mo2C phase. No obvious Pt or Ru XRD peaks were found in the XRD image, indicating that the Pt and Ru nanoparticles did not agglomerate.

[0091] in, Figure 6 Based on the Raman spectra obtained using Pt / Ru@Mo2C, Pt@Mo2C, and Ru@Mo2C according to embodiments and comparative examples of the present invention, the Raman ID / IG ratios indicate that the original Mo2C support itself has the highest defect / disorder degree. After loading the metal, the ID / IG ratios of all samples decreased, indicating that the disorder degree of the material was actually reduced after loading the metal, suggesting that a strong metal-support interaction occurred.

[0092] in, Figure 7 The comparative performance diagrams of electrocatalytic hydrogen evolution using Pt / Ru@Mo2C, Pt@Mo2C, Ru@Mo2C, and 20wt.% Pt / C according to the embodiments and comparative examples of the present invention are shown. Electrochemical hydrogen evolution reaction tests were conducted in 0.5 M H2SO4 solution, with a reaction rate of 0.005 mV·s in the potential range of -0.3 to 0 V (vs RHE). -1 The scan rate was used to test the linear sweep voltammetry curve. At 10 mA cm⁻¹ -2At current densities of 13 mV, 9 mV, 49 mV and 5 mV, respectively, the overpotentials are 13 mV, 9 mV, 49 mV and 5 mV.

[0093] in, Figure 8 The comparative performance diagrams of electrocatalytic hydrogenation using Pt / Ru@Mo2C, Pt@Mo2C, Ru@Mo2C, and 20 wt.% Pt / C, according to embodiments and comparative examples of the present invention, show that the electrochemical hydrogenation reaction was tested in 0.5 M H2SO4 solution at a potential range of 0 ~ 0.5 V (vs RHE) with a reaction rate of 0.002 mV·s. -1 The linear sweep voltammetry curve was obtained using the sweep rate test. At 50 mV, the current density was 3.02 mA cm⁻¹. -2 3.15 mA cm -2 2.84 mA cm -2 and 2.38 mA cm -2 .

[0094] in, Figure 9 The following is a comparative performance diagram of CO anti-poisoning using Pt / Ru@Mo2C, Pt@Mo2CRu@Mo2C, and 20wt.% Pt / C according to embodiments and comparative examples of the present invention. At 50mV, Pt / Ru@Mo2C showed a current decay of only 17% after 1 hour.

[0095] in, Figure 10 According to an embodiment of the present invention, the stability diagram of the proton exchange membrane water electrolysis hydrogen production technology obtained by Pt / Ru@Mo2C is shown at 1A cm⁻¹. -2 At current density, after 1000 hours of operation, the voltage only decreased by 18 mV.

[0096] in, Figure 11 : Figure 11 This is a flowchart of the synthesis process using Pt / Ru@Mo2C according to an embodiment of the present invention.

[0097] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0098] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a HER / HOR bifunctional electrocatalyst for an electrochemical hydrogen pump, characterized in that, The supported electrocatalyst includes a conductive support with a high specific surface area and platinum-ruthenium nanoparticles supported on the conductive support.

2. The supported electrocatalyst as described in claim 1, characterized in that, The conductive carrier is molybdenum carbide nanoflowers; and / or, the metal nanomaterial includes Pt, non-Pt metals, alloys, or non-metallic compounds of metals; and / or, the morphology of the metal nanomaterial is nanoparticles, nanoflowers, nanowires, or nanotubes.

3. A method for preparing a supported electrocatalyst as described in claim 1 or 2, characterized in that: An acidic HER / HOR bifunctional electrocatalyst supported on molybdenum carbide and potassium chloroplatinate and ruthenium trichloride was designed and synthesized. A controllable synthesis method for Pt-Ru-Mo ternary catalysts was established. Through high-temperature carbonization, direct adsorption and other processes, atomic-level dispersion and strong interfacial coupling of Pt and Ru metals on Mo2C support were achieved to construct a uniform nanostructure with abundant active sites. The structure-activity relationship between the catalyst's structural composition and electrocatalytic HER / HOR performance was then systematically studied. The synthesis of the catalyst (Pt / Ru@Mo2C) includes the following steps: The synthesized Mo7-PDA was placed in a tube furnace and kept at 450℃ for 2 h and 800℃ for 3 h under an Ar atmosphere to obtain Mo2C nanoflower carrier with high specific surface area. A metal material solution was added to the carrier solution and stirred to obtain a mixed solution. Sodium borohydride solution was added for reduction, and the solution was filtered and dried to obtain molybdenum carbide-supported platinum-ruthenium metal material. The concentration of the sodium borohydride solution is 0.03 M; The metal nanomaterials include potassium chloroplatinate and / or ruthenium trichloride; The drying process is vacuum drying.

4. The preparation method according to claim 3, characterized in that, The metal nanoparticles have a platinum-ruthenium mass ratio of 1:

1.

5. The method for preparing the molybdenum carbide-supported platinum-ruthenium electrocatalyst as described in claim 3, characterized in that: The content of the precious metal platinum is 10 wt.%.

6. The application of a molybdenum carbide-supported platinum-ruthenium acidic HER / HOR bifunctional catalyst as described in claim 1 or 2 as an electrode modification material in the preparation of electrocatalytic reaction electrodes.

7. An electrode for electrocatalytic HER / HOR, characterized in that, The active component of the electrode includes the supported catalyst described in claim 1 or 2, in which metal nanoparticles are anchored on molybdenum carbide nanoflowers.

8. A method for electrocatalytic HER / HOR, characterized in that, The method uses the electrode described in claim 7 as the working electrode.

9. An acidic HER / HOR bifunctional catalyst that can be used in proton exchange membrane water electrolysis, fuel cells and electrochemical hydrogen pumps.

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