Beta-MnO2 loaded Ru-Ir catalyst as well as preparation method and application thereof

Abstract

The invention discloses a beta-MnO2 loaded Ru-Ir catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalytic materials.The preparation method of the beta-MnO2 loaded Ru-Ir catalyst comprises the following steps: uniformly mixing a manganese salt solution, an iridium salt solution and a ruthenium salt solution to obtain a mixed metal salt solution; dipping the substrate material for hydrogen production by electrolysis of water in a mixed metal salt solution to obtain an adsorbed substrate material; and calcining the adsorbed substrate material at the temperature of between 200 and 240 DEG C in an air atmosphere, so as to obtain the beta-MnO2 loaded Ru-Ir catalyst on the substrate material. The beta-MnO2 loaded Ru-Ir catalyst prepared by the preparation method disclosed by the invention has excellent acidic oxygen evolution reaction performance and stability.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalytic materials, more particularly to a β-MnO2 supported Ru-Ir catalyst, a preparation method and application thereof. BACKGROUND

[0002] With the increasing demand for energy and the growing environmental problems, hydrogen energy has attracted widespread attention as a clean and efficient renewable energy. Water electrolysis is one of the important technologies for hydrogen production, which converts electrical energy into chemical energy through water electrolysis reaction, producing hydrogen and oxygen. In the process of water electrolysis, the acid oxygen evolution reaction is a key step on the anode side, involving a four-electron transfer process, which needs to overcome a large activation energy barrier. Therefore, an efficient acid oxygen evolution reaction catalyst is crucial for improving the efficiency and reducing the energy consumption of water electrolysis for hydrogen production.

[0003] Although significant progress has been made in the research of acid oxygen evolution reaction catalysts, the stability of the catalysts under acidic conditions remains a major challenge. Most existing catalysts are prone to redox reactions and acid corrosion in acidic environments, leading to rapid degradation of active sites. For example, although Ru and Ir-based catalysts have high catalytic activity, Ru-based catalysts are prone to over-oxidation at high potentials, generating unstable RuIVO x species, resulting in the dissolution of active Ru species; while Ir-based catalysts have better corrosion resistance, but their catalytic activity is relatively low. In order to improve the stability and activity of the catalysts, researchers have tried various methods, such as constructing bimetallic sites, introducing support materials or optimizing the microstructure of the catalysts. However, these methods often sacrifice part of the catalytic activity while improving stability, or are difficult to achieve long-term stable operation in practical applications. Moreover, in the prior art, the prepared catalyst needs to be introduced into a substrate material as a working electrode when applied to the oxygen evolution reaction, which is relatively cumbersome to operate.

[0004] In the prior art, the IrRuMnO x catalyst prepared by researchers is a nanorod with a length of more than 100 nm, which has a large size and limited specific surface area, which may limit the contact between the electrolyte and the active sites, affecting the catalytic efficiency. In addition, the surface energy of the nanorod is relatively low, which is not conducive to the stable exposure of active sites, and may gradually deactivate in a long-term reaction. SUMMARY

[0005] In view of the above problems, the present application provides a β-MnO2 supported Ru-Ir catalyst, a preparation method and application thereof. The β-MnO2 supported Ru-Ir catalyst prepared by the preparation method of the present application has excellent acid oxygen evolution reaction performance and stability.

[0006] The first object of the present application is to provide a preparation method of a β-MnO2 loaded Ru-Ir catalyst, comprising the following steps: The manganese salt solution, the iridium salt solution and the ruthenium salt solution are mixed uniformly to obtain a mixed metal salt solution.

[0007] The substrate material for electrolytic water hydrogen production is immersed in the mixed metal salt solution to obtain an adsorbed substrate material.

[0008] The adsorbed substrate material is calcined at 200℃-240℃ under an air atmosphere to obtain a β-MnO2 loaded Ru-Ir catalyst on the substrate material.

[0009] Compared with the prior art, the present application adopts a simple one-step calcination method to prepare the catalyst, which is simple to operate, reduces energy consumption and improves the catalyst output ratio. The method can accurately control the metal salt solution ratio, effectively control the catalyst crystal structure and performance, provide more favorable active site distribution and electronic structure for the catalyst, and thus significantly improve the catalytic activity of the β-MnO2 loaded Ru-Ir catalyst. Moreover, the preparation method is suitable for large-scale production, has important industrial application value, and can be widely applied in the fields of acid oxygen evolution reaction and related electrolytic water hydrogen production. The present application directly optimizes the distribution of Ru and Ir in MnO2 by using the one-step calcination method, forms a stable Ru-O-Ir double site structure, dynamically provides high active sites, and exhibits excellent anti-dissolution and structural stability.

[0010] In a preferred embodiment of the present application, the mass ratio of the manganese salt to the iridium salt is 100:1-1.2.

[0011] The mass ratio of the manganese salt to the ruthenium salt is 100:1-1.2.

[0012] In a preferred embodiment of the present application, the mass ratio of the manganese salt to the iridium salt is 100:1.

[0013] The mass ratio of the manganese salt to the ruthenium salt is 100:1.

[0014] In a preferred embodiment of the present application, the substrate material for electrolytic water hydrogen production is carbon paper.

[0015] In a preferred embodiment of the present application, the calcination temperature is 220℃, and the heating rate during calcination is 5℃ / min-10℃ / min.

[0016] In a preferred embodiment of the present application, the calcination time is 8h-10h, and more preferably, the calcination time is 10h.

[0017] In a preferred embodiment of the present application, the immersion time is 1h-1.5h, and more preferably, the immersion time is 1h.

[0018] A second object of the present application is to provide a beta-MnO2 supported Ru-Ir catalyst prepared by the above preparation method, which has a three-dimensional nanoparticle structure with a particle size of 10-30 nm, and the three-dimensional nanoparticle structure can significantly increase the exposed area of active sites and optimize electrolyte diffusion and charge transport.

[0019] A third object of the present application is to provide an application of the above beta-MnO2 supported Ru-Ir catalyst in water electrolysis for hydrogen production.

[0020] In a preferred embodiment of the present application, the electrolyte in the process of water electrolysis for hydrogen production is a sulfuric acid solution.

[0021] Compared with the prior art, the present application has the following beneficial effects: In the present application, a mixed metal salt solution containing manganese, iridium and ruthenium is used to infiltrate a substrate material for water electrolysis for hydrogen production, and then a beta-MnO2 supported Ru-Ir catalyst is obtained on the substrate material after calcination. The method forms a stable tunnel structure in the beta-MnO2 matrix through calcination, anchors Ru-Ir double sites, modulates charge density using the oxygen affinity difference of Mn, Ru and Ir, and activates O atoms to participate in the reaction. The double sites are synergistically catalyzed by O bridge, which reduces the energy barrier of the rate-determining step of oxygen evolution reaction, and calcination promotes the dynamic evolution of double sites in the reaction, maintains the stability of the distance and coordination number, and improves the structural adaptability. This method is simple to operate, and the prepared catalyst has excellent stability. In the present application, the beta-MnO2 supported Ru-Ir catalyst prepared on the substrate material can be directly used as a working electrode for water electrolysis for hydrogen production without other preparation steps, which is simple to operate.

[0022] The beta-MnO2 supported Ru-Ir catalyst prepared on the substrate material according to the preparation method of the present application has excellent acid oxygen evolution reaction performance, and the overpotential is only 210 mV at a current density of 10 mA·cm -2 -2, and the Tafel slope is as low as 111.84 mV·dec -1 -1, which is much lower than that of pure beta-MnO2, single-atom Ru-MnO2 and Ir-MnO2 catalysts. This means that under the same reaction conditions, the catalyst of the present application can achieve a faster oxygen evolution reaction rate with lower energy consumption, effectively improving the efficiency of water electrolysis for hydrogen production and meeting the large demand for hydrogen in industry.

[0023] The beta-MnO2 supported Ru-Ir catalyst prepared on the substrate material according to the preparation method of the present application has excellent stability, and the overpotential is only 210 mV at a current density of 10 mA·cm -2The constant current density of the timed potential method test was carried out, and after 1700 hours of long-time electrolysis reaction, the electrode potential only increased by 100mV, and the linear sweep voltammetry curve only attenuated by 70mV after the test. In the proton exchange membrane system, the β-MnO2 loaded Ru-Ir catalyst and the commercial PtC were used as the anode and cathode catalysts respectively, and the system could be stably operated for 360h at 60℃, 1000mA·cm -2 current density and the performance attenuation was negligible, far exceeding the commercial IrO2 and RuO2 catalysts. This enables the water electrolysis hydrogen production equipment to operate stably for a long time, reducing the equipment downtime and maintenance cost caused by catalyst replacement. At the same time, the stable catalytic performance ensures the continuity and stability of hydrogen production, and improves the reliability of the production process.

[0024] The prepared catalyst has excellent electrocatalytic performance, which is mainly due to the synergistic effect of Ru-Ir double sites and β-MnO2 matrix. Through the different oxygen affinity of Ru and Ir, the charge density of adjacent oxygen atoms is regulated, and part of the oxygen atoms form strong metal-oxygen bonds to stabilize the structural skeleton, while the other part of the oxygen atoms are activated to participate in the oxygen evolution reaction efficiently. In addition, the oxygen-bridged heteronuclear diatomic site Ru-O-Ir has strong coordination and moderate flexibility, which makes it show excellent adaptability in the dynamic evolution structure. It is confirmed by high-angle annular dark field scanning transmission electron microscopy and X-ray absorption near-edge structure analysis that the distance and coordination number of Ru-Ir double sites almost do not change after 1400 hours of electrocatalytic reaction.

[0025] The preparation method of the catalyst in the application adopts one-step calcination method, which is simple to operate, and by adjusting the solution ratio of Ru³⁺, Ir 4 ⁺ and Mn²⁺, the uniform distribution of Ru and Ir in the MnO2 matrix can be realized. In addition, the catalyst shows excellent anti-dissolution performance in acidic environment, and the loss rate of Mn atoms is only 1 / 9 of that of Ru-MnO2, which further proves its structural stability.

[0026] The preparation method of the application does not require complex process, is suitable for large-scale production, and has important industrial application value. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 is the transmission image of the β-MnO2 loaded Ru-Ir catalyst synthesized in Example 1 of the application, wherein (a) is a high-angle annular dark field scanning transmission electron microscopy image, and (b) is a fast Fourier transform analysis image of the area selected by the dashed line in (a).

[0028] Figure 2is the linear scan voltammetry polarization curve of the synthesized catalyst in 0.5M sulfuric acid solution in Example 1, Comparative Example 1 to Comparative Example 2 and MnO2 of the present application.

[0029] Figure 3 is the chronoamperometry curve of the synthesized catalyst in Example 1 of the present application at 10mA·cm -2 of current density.

[0030] Figure 4 is the transmission image of the Ru-Ir b-site distance change of the β-MnO2 supported Ru-Ir catalyst synthesized in Example 1 of the present application after 1400h electrocatalysis process, wherein, (a) is a high angle annular dark field scanning transmission electron microscope image, and (b) is a fast Fourier transform analysis image of the area selected by the dotted line in (a).

[0031] Figure 5 is the chronoamperometry curve of the RuIr-MnO2||Pt / C proton exchange membrane electrolytic cell operated at 10mA·cm -2 of current density at 60℃ in Application Example 2 of the present application.

[0032] Figure 6 is the scanning electron microscope image of the β-MnO2 supported Ru-Ir catalyst synthesized in Comparative Example 3.

[0033] Figure 7 is the scanning electron microscope image of the β-MnO2 supported Ru-Ir catalyst synthesized in Comparative Example 4.

[0034] Figure 8 is the transmission image of the β-MnO2 supported Ru-Ir catalyst synthesized in Example 2, wherein, a is a transmission electron microscope image, b is a Mn element distribution map, c is an Ir element distribution map, and d is a Ru element distribution map. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0036] In the present application, unless otherwise specified, the raw materials used are all conventional commercially available products in the art, and the operations performed are all under room temperature conditions.

[0037] Example 1 The embodiment provides a preparation method of a beta-MnO2 loaded Ru-Ir catalyst, and specific steps are as shown below. Step 1, manganese nitrate is added to water to prepare a manganese nitrate solution with a mass concentration of 50%.

[0038] Iridium chloride is added to water to prepare an iridium chloride solution with a concentration of 10 mg / mL.

[0039] Ruthenium chloride is added to water to prepare a ruthenium chloride solution with a concentration of 10 mg / mL.

[0040] Step 2, 200 μL of the manganese nitrate solution, 100 μL of the iridium chloride solution and 100 μL of the ruthenium chloride solution are taken and added to the same beaker, and magnetic stirring is performed for 10 minutes to obtain a mixed metal salt aqueous solution.

[0041] After the magnetic stirring is completed, a carbon paper with a size of 2 cm*1 cm is taken, and is stably clamped and fixed, so that the area of the carbon paper immersed in the mixed metal salt aqueous solution is 1 cm*1 cm. After 1 hour, the carbon paper is fully soaked with the solution to obtain the adsorbed carbon paper.

[0042] Step 3, the adsorbed carbon paper is placed in a porcelain boat, and the porcelain boat is placed in a muffle furnace to complete calcination in an air atmosphere, an air flow rate is 100 mL·min -1 , a pyrolysis temperature is 220 DEG C, and a temperature rising rate is 5 DEG C·min -1 , the temperature is kept constant at 220 DEG C for 10 hours, and then natural cooling is performed, and a beta-MnO2 loaded Ru-Ir catalyst is obtained on the carbon paper. In order to facilitate subsequent description, the final product prepared in the embodiment is recorded as a beta-MnO2 loaded Ru-Ir catalyst.

[0043] Embodiment 2 The embodiment provides a preparation method of a beta-MnO2 loaded Ru-Ir catalyst, and specific steps are as shown below. Step 1, manganese nitrate is added to water to prepare a manganese nitrate solution with a mass concentration of 50%.

[0044] Iridium chloride is added to water to prepare an iridium chloride solution with a concentration of 10 mg / mL.

[0045] Ruthenium chloride is added to water to prepare a ruthenium chloride solution with a concentration of 10 mg / mL.

[0046] Step 2, 200 μL of the manganese nitrate solution, 100 μL of the iridium chloride solution and 100 μL of the ruthenium chloride solution are taken and added to the same beaker, and magnetic stirring is performed for 10 minutes to obtain a mixed metal salt aqueous solution.

[0047] After the magnetic stirring is completed, carbon paper with a size of 2 cm x 1 cm is taken, and is stably clamped and fixed, so that the area of the carbon paper immersed in the mixed metal salt aqueous solution is 1 cm x 1 cm. After 1.5 hours, the carbon paper is fully absorbed with the solution, and the carbon paper after adsorption is obtained.

[0048] Step 3, the carbon paper after adsorption is placed in a porcelain boat, and the porcelain boat is placed in a muffle furnace to complete calcination under an air atmosphere, the air flow rate is 100 mL·min -1 , the pyrolysis temperature is 200 ℃, and the heating rate is 10 ℃·min -1 , and the temperature is kept constant at 200 ℃ for 9 hours, and then the temperature is naturally lowered, and a β-MnO2 supported Ru-Ir catalyst is obtained on the carbon paper. In order to facilitate subsequent description, the final product prepared in this example is denoted as β-MnO2 supported Ru-Ir catalyst.

[0049] Example 3 The present example provides a preparation method of a β-MnO2 supported Ru-Ir catalyst, and the specific steps are as follows: Step 1, manganese nitrate is added to water to prepare a manganese nitrate solution with a mass concentration of 50%.

[0050] Iridium chloride is added to water to prepare an iridium chloride solution with a concentration of 10 mg / mL.

[0051] Ruthenium chloride is added to water to prepare a ruthenium chloride solution with a concentration of 10 mg / mL.

[0052] Step 2, 200 μL of the manganese nitrate solution, 120 μL of the iridium chloride solution, and 120 μL of the ruthenium chloride solution are taken and added to the same beaker, and the mixture is magnetically stirred for 10 minutes to obtain a mixed metal salt aqueous solution.

[0053] After the magnetic stirring is completed, carbon paper with a size of 2 cm x 1 cm is taken, and is stably clamped and fixed, so that the area of the carbon paper immersed in the mixed metal salt aqueous solution is 1 cm x 1 cm. After 1.3 hours, the carbon paper is fully absorbed with the solution, and the carbon paper after adsorption is obtained.

[0054] Step 3, the carbon paper after adsorption is placed in a porcelain boat, and the porcelain boat is placed in a muffle furnace to complete calcination under an air atmosphere, the air flow rate is 100 mL·min -1 , the pyrolysis temperature is 240 ℃, and the heating rate is 8 ℃·min -1 , and the temperature is kept constant at 240 ℃ for 8 hours, and then the temperature is naturally lowered, and a β-MnO2 supported Ru-Ir catalyst is obtained on the carbon paper. In order to facilitate subsequent description, the final product prepared in this example is denoted as β-MnO2 supported Ru-Ir catalyst.

[0055] Comparative Example 1 The comparative example provides a preparation method of a β-MnO2 loaded Ru catalyst, and the specific steps are as shown below: Step 1, manganese nitrate is added to water to prepare a manganese nitrate solution with a mass concentration of 50%.

[0056] Ruthenium chloride is added to water to prepare a ruthenium chloride solution with a concentration of 10 mg / mL.

[0057] Step 2, 200 μL of the manganese nitrate solution and 100 μL of the ruthenium chloride solution are taken into the same beaker, and magnetic stirring is performed for 10 minutes to obtain a mixed metal salt aqueous solution.

[0058] After magnetic stirring is completed, carbon paper with a size of 2 cm x 1 cm is taken, and is stably clamped and fixed so that the area of the carbon paper immersed in the mixed metal salt aqueous solution is 1 cm x 1 cm. After 1 hour, the carbon paper is fully absorbed in the solution to obtain the adsorbed carbon paper.

[0059] Step 3, the adsorbed carbon paper is placed in a porcelain boat, and the porcelain boat is placed in a muffle furnace to complete calcination under an air atmosphere, the air flow rate is 100 mL·min -1 , the pyrolysis temperature is 220 ℃, and the heating rate is 5 ℃·min -1 , and the temperature is kept at 220 ℃ for 10 hours, and then the temperature is naturally lowered, and a β-MnO2 loaded Ru catalyst is obtained on the carbon paper. In order to facilitate subsequent description, the final product prepared in this example is denoted as a β-MnO2 loaded Ru catalyst.

[0060] Comparative Example 2 The comparative example provides a preparation method of a β-MnO2 loaded Ir catalyst, and the specific steps are as shown below: Step 1, manganese nitrate is added to water to prepare a manganese nitrate solution with a mass concentration of 50%.

[0061] Iridium chloride is added to water to prepare an iridium chloride solution with a concentration of 10 mg / mL.

[0062] Step 2, 200 μL of the manganese nitrate solution and 100 μL of the iridium chloride solution are taken into the same beaker, and magnetic stirring is performed for 10 minutes to obtain a mixed metal salt aqueous solution.

[0063] After magnetic stirring is completed, carbon paper with a size of 2 cm x 1 cm is taken, and is stably clamped and fixed so that the area of the carbon paper immersed in the mixed metal salt aqueous solution is 1 cm x 1 cm. After 1 hour, the carbon paper is fully absorbed in the solution to obtain the adsorbed carbon paper.

[0064] Step 3, the adsorbed carbon paper is placed in a porcelain boat, and the porcelain boat is placed in a muffle furnace to complete calcination under an air atmosphere, the air flow rate is 100 mL·min -1, the pyrolysis temperature is 220℃, and the temperature rising rate is 5℃·min -1 , and then naturally cooled down, and the β-MnO2 loaded Ir catalyst was obtained on the carbon paper.

[0065] Comparative Example 3 This comparative example provides a preparation method of a β-MnO2 loaded Ru-Ir catalyst, and the specific steps are as follows: Step 1, manganese nitrate was added to water to prepare a manganese nitrate solution with a mass concentration of 50%.

[0066] Iridium chloride was added to water to prepare an iridium chloride solution with a concentration of 10 mg / mL.

[0067] Ruthenium chloride was added to water to prepare a ruthenium chloride solution with a concentration of 10 mg / mL.

[0068] Step 2, 200 μL of the manganese nitrate solution, 100 μL of the iridium chloride solution, and 100 μL of the ruthenium chloride solution were measured and added to the same beaker, and magnetic stirring was performed for 10 minutes to obtain a mixed metal salt aqueous solution.

[0069] After the magnetic stirring was completed, a carbon paper with a size of 2 cm×1 cm was taken and stably clamped and fixed, so that the area of the carbon paper immersed in the mixed metal salt aqueous solution was 1 cm×1 cm. After 1 hour, the carbon paper was fully absorbed, and the adsorbed carbon paper was obtained.

[0070] Step 3, the adsorbed carbon paper was placed in a porcelain boat, and the porcelain boat was placed in a muffle furnace to complete calcination in an air atmosphere, and the air flow rate was 100 mL·min -1 , the pyrolysis temperature is 280℃, and the temperature rising rate is 5℃·min -1 , and then naturally cooled down, and the β-MnO2 loaded Ru-Ir catalyst was obtained on the carbon paper. In order to facilitate subsequent description, the final product prepared in this example is referred to as the β-MnO2 loaded Ru-Ir catalyst.

[0071] Comparative Example 4 This comparative example provides a preparation method of a β-MnO2 loaded Ru-Ir catalyst, and the specific steps are as follows: Step 1, manganese nitrate was added to water to prepare a manganese nitrate solution with a mass concentration of 50%.

[0072] Iridium chloride was added to water to prepare an iridium chloride solution with a concentration of 10 mg / mL.

[0073] Ruthenium chloride was added to water to prepare a ruthenium chloride solution with a concentration of 10 mg / mL.

[0074] Step 2, 200 μL of manganese nitrate solution, 100 μL of iridium chloride solution and 100 μL of ruthenium chloride solution were measured and added into the same beaker, and a mixed metal salt aqueous solution was obtained by magnetic stirring for 10 minutes.

[0075] After the magnetic stirring was completed, a carbon paper with a size of 2 cm x 1 cm was taken and stably clamped and fixed, so that the area of the carbon paper immersed in the mixed metal salt aqueous solution was 1 cm x 1 cm. After 1 hour, the carbon paper was fully absorbed by the solution to obtain the adsorbed carbon paper.

[0076] Step 3, the adsorbed carbon paper was placed in a porcelain boat, and the porcelain boat was placed in a muffle furnace to complete calcination under an air atmosphere, the air flow rate was 100 mL·min -1 , the pyrolysis temperature was 220℃, and the heating rate was 5℃·min -1 , and the temperature was kept at 220℃ for 24 hours, and then the temperature was naturally lowered, and a β-MnO2 supported Ru-Ir catalyst was obtained on the carbon paper. In order to facilitate subsequent description, the final product prepared in this example is referred to as a β-MnO2 supported Ru-Ir catalyst.

[0077] Application Example 1 The β-MnO2 supported Ru-Ir catalyst prepared in Example 1 was applied to the electrolysis of water to produce hydrogen: the final product obtained in Example 1 was used as an electrode sheet, a standard three-electrode system was used, a carbon rod was used as a counter electrode, a saturated Ag / AgCl electrode was used as a reference electrode, and the above-prepared electrode sheet was used as a working electrode. The working electrode was tested in a 0.5 M sulfuric acid solution.

[0078] Application Example 2 The β-MnO2 supported Ru-Ir catalyst prepared in Example 1 was applied to a proton exchange membrane electrolytic cell, and the specific steps were as follows: Step 1, the β-MnO2 supported Ru-Ir catalyst prepared in Example 1 was taken, and a loading amount of 1 mg / cm 2 was uniformly coated on a carbon paper with a size of 2.2 cm x 2.2 cm to obtain a RuIr-MnO2 carbon paper, which was used as an anode electrode.

[0079] A commercial Pt / C catalyst was taken, and a loading amount of 1 mg / cm 2 was uniformly coated on a carbon paper with a size of 2.2 cm x 2.2 cm to obtain a Pt / C carbon paper, which was used as a cathode electrode. The commercial Pt / C used in the present application was 40% Pt / C, that is, in 100 grams of Pt / C catalyst, 40 grams of platinum was contained, and the remaining 60 grams was a carbon carrier.

[0080] Step 2, the N117 film was cut to a size of 2.2 cm x 2.2 cm.

[0081] Step 3: Assemble the proton exchange membrane electrolyzer cell. First, place the bipolar plate with the serpentine flow field side facing up. Install the anode electrode, ensuring the catalyst layer is in contact with the flow field. Then, cover with the N117 proton exchange membrane. Install the cathode electrode, ensuring the catalyst layer is in contact with the membrane. Finally, cover with another bipolar plate, with the serpentine flow field side facing down, ensuring the flow field is aligned with the cathode electrode.

[0082] Step 4: Use the KMem single-cell water electrolysis hydrogen production tester model AE01, place the electrolyzer in a constant temperature environment of 60°C, and apply 1000mA / cm 2 The cell voltage was monitored in real time at a constant current density of 100 nm and operated continuously for 360 h.

[0083] See also Figure 1 , Figure 1 In (a), it can be seen that the β-MnO2-supported Ru-Ir catalyst synthesized in Example 1 of the present invention has a unique microstructure. The bright spots represent heavy atoms, while the darker background is the β-MnO2 support. The Ru-Ir diatomic pairs are marked with circles, and the distance between the two is about 3Å. The fast Fourier transform of the dotted box area is obtained. Figure 1 (b) shows clear diffraction spots corresponding to the (110) crystal plane of β-MnO2, proving that the Ru-Ir double site is embedded in the β-MnO2 lattice without forming metal clusters, and the Ru-Ir diatoms are uniformly distributed in the β-MnO2 lattice.

[0084] See also Figure 2 When the β-MnO2 supported Ru-Ir catalyst synthesized in Example 1 of the present invention is subjected to oxygen evolution reaction in 0.5 mol / L sulfuric acid solution, the -2 At this current density, the overpotential is only 210 mV.

[0085] See also Figure 2 The Ru-MnO2 synthesized in Comparative Example 1 was in 0.5 mol / L sulfuric acid solution at 10 mA cm -2 The overpotential at this current density was 300 mV, which is approximately 30% lower than that of the Ru-Ir catalyst. In comparison, the β-MnO2-supported Ru-Ir catalyst of the present invention exhibited a lower overpotential, indicating higher catalytic activity. This is due to the synergistic effect of the dual sites, which provide more active sites for the reaction and accelerate the reaction process.

[0086] See also Figure 2 In comparative example 2, the Ir-MnO2 synthesized in 0.5 mol / L sulfuric acid solution was 10 mA cm -2The overpotential under the current density is 280 mV, and the overpotential of the Ru-Ir catalyst loaded on the β-MnO2 is reduced by about 25%. In comparison again, the Ru-Ir catalyst loaded on the β-MnO2 of the present application has obvious advantages in reducing the overpotential and improving the catalytic activity, and the double-site structure makes the reaction kinetics more favorable, and can more efficiently promote the oxygen evolution.

[0087] Referring to Figure 3 , the Ru-Ir catalyst loaded on the β-MnO2 synthesized in Example 1 of the present application has an overpotential of 210 mV@10 mA / cm -2 The timed potential method test is carried out under the current density, and after 1700 hours of test, the electrode potential only increases by 100 mV, showing excellent stability. The mass fraction of Ru in the Ru-MnO2 synthesized in Comparative Example 1 of the present application is 3.49wt%, and the mass fraction of Ir in the Ir-MnO2 synthesized in Comparative Example 2 is 2.87wt%, while the mass fractions of Ru and Ir in the RuIr-MnO2 synthesized in Example 1 are only 1.81wt% and 1.54wt% respectively, and the loading amount of the bimetallic catalyst is significantly lower than that of the single-metal catalyst. However, experiments show that the RuIr-MnO2 performs the best OER performance in 0.5mol / L sulfuric acid, with an overpotential of only 210 mV@10 mA / cm 2 , and a stability of 1700h, far exceeding the single-metal catalyst.

[0088] Referring to Figure 3 , the Ru-MnO2 synthesized in Comparative Example 1 of the present application has an overpotential of 280 mV@10 mA / cm -2 The timed potential method test is carried out under the current density, and after 1700 hours of test, the electrode potential only increases by 100 mV, showing excellent stability. The mass fraction of Ru in the Ru-MnO2 synthesized in Comparative Example 1 of the present application is 3.49wt%, and the mass fraction of Ir in the Ir-MnO2 synthesized in Comparative Example 2 is 2.87wt%, while the mass fractions of Ru and Ir in the RuIr-MnO2 synthesized in Example 1 are only 1.81wt% and 1.54wt% respectively, and the loading amount of the bimetallic catalyst is significantly lower than that of the single-metal catalyst. However, experiments show that the RuIr-MnO2 performs the best OER performance in 0.5mol / L sulfuric acid, with an overpotential of only 210 mV@10 mA / cm 2 , and a stability of 1700h, far exceeding the single-metal catalyst.

[0089] Referring to Figure 4 , Figure 4 (a) in the figure is the microstructure of the Ru-Ir catalyst loaded on the β-MnO2 synthesized in Example 1 of the present application after 1400h electrocatalysis, and the crystal lattice stripes of the carrier almost disappear, but the Ru-Ir double-atom pairs marked by the circles still exist, and the distance of the Ru-Ir double sites always remains about 3Å, and the structural stability is good, Figure 4 (b) in the figure shows a weak diffuse ring, and the short-range order signal of the Ru-Ir double sites can still be identified, indicating that the carrier has been highly amorphized, but the stability of the active center is independent of the long-range order of the carrier.

[0090] Referring to Figure 5, the initial potential of the electrolytic cell is about 1.8V, and after 360h of continuous operation, the potential only rises by 1.82V, with a decay rate of only 2.2%, and no obvious fluctuations. This shows that the β-MnO2 supported Ru-Ir catalyst as an anode catalyst still maintains excellent stability under the harsh conditions of strong acidity, industrial-grade high current density and high temperature, without significant metal dissolution or active site deactivation. It is confirmed that it has practical application potential in proton exchange membrane electrolytic cells.

[0091] Figure 6 and Figure 7 The scanning electron micrographs of the β-MnO2 supported Ru-Ir catalysts synthesized in Comparative Example 3 and Comparative Example 4, respectively, show that the calcination treatment at this temperature and time causes the catalyst to agglomerate, which is not conducive to contact with the electrolyte in the electrocatalytic reaction. The β-MnO2 supported Ru-Ir catalysts prepared in Comparative Example 3 and Comparative Example 4 have almost no catalytic performance.

[0092] It can be seen that the β-MnO2 supported Ru-Ir catalyst has a significant advantage in catalytic activity and stability compared to the single-atom Ru-MnO2 and Ir-MnO2 catalysts. The dual-site structure effectively improves the catalyst performance by adjusting the charge density, providing more active sites, and enhancing the structural stability. The unit point catalyst performs poorly in these aspects and is difficult to achieve the performance level of the dual-site catalyst.

[0093] In the samples prepared in Example 2 and Example 3, Ru and Ir are uniformly distributed in the MnO2 matrix. As shown in Figure 8 , according to the TEM image and element distribution map, it can be observed that the sample prepared in Example 2 is a particle with a uniform particle size of about 10nm, and the Mn element, Ir element and Ru element are uniformly distributed in the sample. It should be noted that, Figure 8 In a of, HAADF is an abbreviation of high-angle annular dark field imaging.

[0094] Although preferred embodiments of the present application have been described, those skilled in the art, once aware of the basic inventive concept, can make additional changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present application.

[0095] Obviously, those skilled in the art can make various modifications and variations to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include these modifications and variations.

Claims

1. A method for preparing a β-MnO2-loaded Ru-Ir catalyst, characterized in that: The following steps are involved: uniformly mixing a manganese salt solution, an iridium salt solution, and a ruthenium salt solution to obtain a mixed metal salt solution; impregnating a base material for hydrogen production by electrolysis of water in a mixed metal salt solution to obtain an adsorbed base material; The adsorbed base material is calcined at 200° C. to 240° C. in an air atmosphere to obtain a β-MnO2-loaded Ru-Ir catalyst on the base material.

2. The method for preparing a β-MnO2-loaded Ru-Ir catalyst according to claim 1, characterized in that: The mass ratio of manganese salt to iridium salt is 100:1~1.2; The mass ratio of manganese salt to ruthenium salt is 100:1~1.

2.

3. The method for preparing a β-MnO2-loaded Ru-Ir catalyst according to claim 2, characterized in that: The mass ratio of manganese salt to iridium salt is 100:1; The mass ratio of manganese salt to ruthenium salt is 100:

1.

4. The method for preparing a β-MnO2-loaded Ru-Ir catalyst according to claim 1, characterized in that: The base material for hydrogen production by water electrolysis is carbon paper.

5. The method for preparing a β-MnO2-loaded Ru-Ir catalyst according to claim 1, characterized in that: The calcination temperature is 220°C, and the heating rate during calcination is 5°C / min~10°C / min.

6. The method for preparing a β-MnO2-loaded Ru-Ir catalyst according to claim 1, characterized in that: The calcination time is 8h~10h.

7. The method for preparing a β-MnO2-supported Ru-Ir catalyst according to claim 1, characterized in that: The immersion time is 1h~1.5h.

8. A β-MnO2-supported Ru-Ir catalyst prepared by the preparation method according to any one of claims 1 to 7, characterized in that: The β-MnO2-loaded Ru-Ir catalyst has a three-dimensional nanoparticle structure with a particle size of 10nm~30nm.

9. Use of the β-MnO2-loaded Ru-Ir catalyst according to claim 8 in hydrogen production by water electrolysis.

10. The use of the MnO2-supported Ru-Ir catalyst in hydrogen production by water electrolysis according to claim 9, characterized in that: In the process of electrolyzing water to produce hydrogen, the electrolyte is sulfuric acid solution.

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