Preparation method and application of nanoscale Ru-B material

Abstract

This invention discloses a method for preparing nanoscale Ru-B materials and their applications. The method for preparing nanoscale Ru-B materials is as follows: Ruthenium salt and sodium tetraborate are weighed according to an elemental ratio of Ru:B = 1:0.4~0.8, ground and mixed, and the mixture is transferred to a Joule heating apparatus. Under inert gas protection, it is heated to a final temperature of not less than 1200℃ to obtain Ru-B materials. The Ru-B materials prepared by this method have high dispersibility. Using ultrasonic spraying technology, the catalyst slurry can be directly deposited on the proton exchange membrane to form a catalyst layer with controllable thickness, uniform distribution, and well-developed pore structure. The prepared membrane layer has high stability. At a voltage of 1.75 V and a current density of 2 A / cm², the membrane layer can withstand high pressure. 2 Under certain conditions, it can operate stably for more than 40 hours.

Description

Technical Field

[0001] This invention relates to a method for preparing a catalytic material, particularly a method for preparing a nanoscale Ru-B material, and also to the application of Ru-B obtained by this method. Background Technology

[0002] Proton exchange membrane (PEM) water electrolysis for hydrogen production or fuel cells relies on the precious metal platinum (Pt) catalyst, but Pt is expensive. Ruthenium (Ru) is relatively inexpensive and has high intrinsic activity for the oxygen evolution reaction (OER), but pure Ru is easily dissolved and oxidized under the strong acidity and high potential conditions of PEM, resulting in insufficient stability. To address this issue, introducing boron (B) to form boron-ruthenium alloys (or ruthenium boride) has become an effective modification strategy. The principle is that the incorporation of B can adjust the electronic structure of Ru, weaken the adsorption strength of Ru with intermediate products, optimize the reaction pathway, and thus improve the intrinsic activity of OER. More importantly, the addition of B can enhance the structural stability and corrosion resistance of the alloy, inhibit the dissolution and excessive oxidation of Ru, and significantly extend the electrode life. How to prepare ruthenium boride is a problem that needs to be solved. CN 118387891 A discloses a metal boride electrolysis water catalyst and a flash evaporation Joule heating method for its preparation. The catalyst has good stability and catalytic activity, but the resulting compound has low dispersibility and requires further grinding before use, which is not conducive to its use as a spraying material. Sodium borohydride, used as the boron source, has a decomposition temperature lower than the boride formation temperature, and the synthesis process carries certain risks. Summary of the Invention

[0003] Purpose of the invention: The purpose of this invention is to provide a method for preparing Ru-B materials that helps improve dispersibility. Another purpose of this invention is to provide an application of Ru-B materials.

[0004] Technical solution: The present invention describes a method for preparing nanoscale Ru-B materials, wherein ruthenium salt and sodium tetraborate are weighed according to an elemental molar ratio of Ru:B = 1: 0.4 ~ 0.8, ground and mixed, and the mixture is transferred to a Joule heating reactor and heated to a final temperature of not less than 1200℃ under inert gas protection to obtain Ru-B.

[0005] Preferably, the temperature is heated to a final temperature of not less than 1300°C.

[0006] Preferably, at the final temperature, the duration does not exceed 5 seconds. More preferably, the duration does not exceed 3 seconds.

[0007] Preferably, Ru : B = 1 : 0.7~0.75.

[0008] Preferably, the ruthenium salt is at least one of trivalent ruthenium hydrochloride, sulfate, and phosphate.

[0009] Preferably, the inert gas is at least one of argon, nitrogen, and hydrogen.

[0010] Application of Ru-B material prepared by the aforementioned method in proton exchange membrane slurry.

[0011] Preferably, the Ru-B material is sprayed onto both sides of the proton exchange membrane using ultrasonic spraying.

[0012] Beneficial Effects: Compared with the prior art, the present invention has the following significant advantages: 1. The Ru-B material prepared by this method has high dispersibility. The ultrasonic spraying process can directly deposit the catalyst slurry onto the proton exchange membrane to form a catalyst layer with controllable thickness, uniform distribution, and well-developed pore structure, ensuring rapid transport of reaction gas / liquid, protons, electrons, and product water, greatly reducing mass transfer resistance such as concentration polarization, thereby improving the working current density and energy conversion efficiency of the electrode; 2. Through the Joule heating method, an ultra-fast and high-temperature synthesis technology, Ru-B with a clear stoichiometric ratio and highly ordered crystal structure is precisely prepared. The material is an intermetallic compound, and the electronic structure of the Ru active site is optimized, making its adsorption energy for key intermediates in the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) close to the theoretical optimum. The resulting catalyst exhibits OER activity comparable to or even better than commercial IrO2 and HER activity close to that of commercial Pt / C in acidic electrolytes. 3. It has extremely high intrinsic stability: it fundamentally inhibits the dissolution and oxidative loss of Ru at high anodic potentials (avoiding the formation of volatile RuO4), and also effectively prevents the aggregation and growth of nanoparticles during cycling. The prepared film can withstand a voltage of 1.75 V and a current density of 2 A / cm. 2 Under these conditions, it can operate stably for more than 40 hours, significantly extending the lifespan of PEM electrolyzers or fuel cells; the ultrasonic spraying process is mature and easy to scale up, and the overall process is simple and controllable, with good prospects for large-scale production. Attached Figure Description

[0013] Figure 1 The XRD patterns are of the samples obtained in Examples 1 to 3;

[0014] Figure 2 The hydrogen evolution reaction curves are for the samples obtained in Examples 1 to 3;

[0015] Figure 3 The oxygen evolution reaction curves of the samples obtained in Examples 1 to 3 are shown.

[0016] Figure 4 The IT test curve of a PEM single cell at 1.75 V is shown for the sample prepared in Example 1.

[0017] Figure 5 The image shown is a transmission electron microscope (TEM) image of the sample prepared in Example 1. Detailed Implementation

[0018] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0019] Example 1: 1 g of RuCl3·xH2O powder and Na2B4O7·10H2O powder with a molar ratio of 11:2 was accurately weighed. The two powders were thoroughly ground and mixed in a mortar to obtain a precursor mixture. The homogeneous precursor powder was placed in a specially designed reaction chamber with electrodes connected to both ends. After evacuating the system, an inert protective gas (such as argon) was introduced. Subsequently, a 50V voltage and 80A current pulse were applied to the precursor powder through a capacitor bank. Due to its own resistance, the precursor powder generated an instantaneous ultra-high temperature exceeding 1200°C within seconds (Joule heating effect, temperature reaching 1200°C, duration not exceeding 2 seconds), promoting a solid-state alloying reaction between Ru and B elements to generate the target product. After the reaction was completed, the obtained solid product was cooled to room temperature.

[0020] The solid product is removed and washed with a dilute acid solution (such as dilute hydrochloric acid) to remove soluble salt byproducts (such as sodium chloride) generated during the reaction. Finally, it is repeatedly washed with deionized water until neutral and then vacuum dried to obtain high-purity nano-sized Ru. 11 B8 intermetallic compound powder. The transmission electron microscopy image of the product obtained in this example is shown below. Figure 5 As shown, the product is highly dispersed and shows no aggregation.

[0021] Example 2: 1 g of RuCl3·xH2O powder and Na2B4O7·10H2O powder with a molar ratio of 28:3 was accurately weighed. The two powders were thoroughly ground and mixed in a mortar to obtain a precursor mixture. The uniformly mixed precursor powder was placed in a specially designed reaction chamber with electrodes connected to both ends. After evacuating the system, an inert protective gas (such as argon) was introduced. Subsequently, a transient high-voltage, high-current pulse was applied to the precursor powder through a capacitor bank. Due to its own resistance, the precursor powder generated a transient ultra-high temperature exceeding 1500°C within seconds (Joule heating effect), promoting a solid-state alloying reaction between Ru and B elements to generate the target product. After the reaction, the obtained solid product was cooled to room temperature. After removal, it was washed with a dilute acid solution (such as dilute hydrochloric acid) to remove soluble salt byproducts (such as sodium chloride) generated during the reaction. Finally, the powder is repeatedly washed with deionized water until neutral and then vacuum dried to obtain high-purity, highly dispersed nano-sized Ru7B3 intermetallic compound powder.

[0022] Example 3: Accurately weigh 1 g of RuCl3·xH2O powder and Na2B4O7·10H2O powder in a molar ratio of 8:1. Grind and mix them thoroughly in a mortar to obtain a precursor mixture. Place the homogeneous precursor powder in a specially designed reaction chamber with electrodes connected to both ends. After evacuating the system, fill it with an inert protective gas (such as argon). Subsequently, apply a transient high-voltage, high-current pulse to the precursor powder through a capacitor bank. Due to its own resistance, the precursor powder generates a transient ultra-high temperature (Joule heating effect) exceeding 1400°C within seconds, promoting a solid-state alloying reaction between Ru and B elements to generate the target product. After the reaction, cool the obtained solid product to room temperature. After removal, wash it with a dilute acid solution (such as dilute hydrochloric acid) to remove soluble salt byproducts (such as sodium chloride) generated during the reaction. Finally, wash repeatedly with deionized water until neutral and vacuum dry to obtain high-purity nano-sized Ru2B intermetallic compound powder.

[0023] First, such as Figure 1 The crystal structure and composition of the Ru-B series catalyst materials prepared in Examples 1 to 3 were analyzed by X-ray diffraction (XRD). The products of Examples 1 to 3 were consistent with standard cards PDF#30-1102, PDF#38-1302 and PDF#15-0213, respectively, proving that the synthesized Ru-B series compounds were all pure phases. The molar ratios were consistent with the chemical formulas by energy dispersive spectroscopy analysis.

[0024] After confirming that the catalyst was a pure phase, its hydrogen evolution reaction and oxygen evolution reaction performance were tested using a three-electrode system in 0.5 M H₂SO₄ solution. Figure 2 and Figure 3 As shown, the catalyst in Example 1 exhibits excellent catalytic activity, achieving 10 mA / cm² with a hydrogen evolution reaction overpotential of only 10 mV. 2 At a current density of only 226 mV, the oxygen evolution reaction overpotential can reach 10 mA / cm². 2 Current density, 10 mA / cm 2 At the given current density, the hydrogen evolution reaction overpotentials in Examples 2 and 3 were 12V and 16mV, respectively, at 100mA / cm². 2 At the given current density, the overpotentials for the hydrogen evolution reaction in Examples 1-3 were 23, 31, and 29 mV, respectively.

[0025] In addition to electrochemical performance testing, the stability of the PEM membrane electrode assembly prepared from the materials obtained in the above embodiments was also evaluated. The procedure was as follows: the product obtained in Example 1 was taken and ultrasonically sprayed onto both sides of the proton exchange membrane, placed in a 5×5 cm PEM test tank, and tested in a pure water environment at 60°C. The results are as follows. Figure 4 As shown, at a voltage of 1.75 V, its current density can reach 2 A / cm². 2 The component operated stably for 40 hours under these conditions, demonstrating its reliability and durability under continuous operation. This result further confirms Ru's... 11 The application potential of B8 catalyst in the PEM system provides experimental evidence for its long-term operation in related energy conversion equipment.

[0026] Comparative Example 1: This comparative example is similar to Example 2, except that the final heating temperature is 1100°C, and the resulting sample is a non-pure phase.

Claims

1. A method for preparing nanoscale Ru-B materials, characterized in that, According to the elemental molar ratio Ru : B = 1 : 0.4 ~ 0.8, ruthenium salt and sodium tetraborate were weighed separately, ground and mixed, and the mixture was transferred to a Joule heating apparatus. Under the protection of inert gas, it was heated to a final temperature of not less than 1200℃ to obtain Ru-B material.

2. The method for preparing nanoscale Ru-B materials according to claim 1, characterized in that, Heat to a final temperature of not less than 1300℃.

3. The method for preparing nanoscale Ru-B materials according to claim 1, characterized in that, At the final temperature, the duration shall not exceed 5 seconds.

4. The method for preparing nanoscale Ru-B materials according to claim 3, characterized in that, The duration shall not exceed 3 seconds.

5. The method for preparing nanoscale Ru-B materials according to claim 1, characterized in that, Ru : B = 1:0.7~0.

75.

6. The method for preparing nanoscale Ru-B materials according to claim 1, wherein the ruthenium salt is at least one of trivalent ruthenium hydrochloride, sulfate, and phosphate.

7. The method for preparing nanoscale Ru-B materials according to claim 1, characterized in that, The inert gas is at least one of argon, nitrogen, and hydrogen.

8. The application of the Ru-B material prepared by any one of the preparation methods of claims 1 to 7 in proton exchange membrane slurries.

9. The application according to claim 8, characterized in that, The Ru-B material was sprayed onto both sides of the proton exchange membrane using ultrasonic spraying.

Images