A catalyst for boron-doped ruthenium dioxide hollow fibers, its preparation method and application

Abstract

This invention relates to the field of electrocatalyst technology, specifically to a boron-doped ruthenium dioxide hollow fiber catalyst, its preparation method, and its application. Using sodium alginate as raw material, it is spun into calcium alginate fibers via a wet spinning process. The calcium alginate fibers are mixed with boric acid solution, washed, and dried to obtain boric acid-crosslinked calcium alginate fibers. These boric acid-crosslinked calcium alginate fibers are then thoroughly mixed with ruthenium trichloride solution and dried to obtain a boric acid-crosslinked ruthenium alginate fiber precursor. Subsequent pyrolysis converts ruthenium ions into ruthenium dioxide nanoparticles, transforming the boric acid-crosslinked alginate fibers into hollow fibers. Boron atoms are incorporated into the ruthenium dioxide lattice to form a boron-doped ruthenium dioxide oxygen evolution reaction electrocatalyst. Boron-doped ruthenium dioxide hollow fibers can be used as high-performance proton exchange membrane electrolyzers and water electrolysis catalysts, exhibiting high catalytic activity and good stability. The raw materials are widely available, require no expensive equipment, and can be prepared in large quantities.

Description

Technical Field

[0001] This invention relates to the field of electrocatalyst technology, specifically to a boron-doped ruthenium dioxide hollow fiber catalyst, its preparation method, and its application. Background Technology

[0002] Renewable energy-driven water electrolysis technologies, such as alkaline water electrolysis (AWE) and proton exchange membrane water electrolysis (PEMWE), offer promising pathways for hydrogen production. Notably, PEMWE has attracted significant attention due to its rapid reaction kinetics, high hydrogen purity, high current density, and good compatibility with renewable energy sources. However, hydrogen production efficiency is limited by the slow kinetics of the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), particularly the latter. Non-precious metal (e.g., cobalt and nickel) based materials can effectively accelerate the kinetics of water electrolysis in alkaline electrolytes; however, under acidic conditions, especially in the strongly oxidizing environment of acidic OERs, their structures are susceptible to corrosion, leading to catalytic deactivation.

[0003] Ruthenium (Ru) and iridium (Ir)-based oxides are widely considered the benchmark electrocatalysts for acidic OERs. Ruthenium-based electrocatalysts are superior to iridium-based electrocatalysts in terms of activity and cost; however, they exhibit poor stability. The instability of Ru-based materials mainly stems from the over-oxidation of Ru species, forming soluble RuO4 species. Introducing divalent and trivalent metals (such as Co, Zn, and Cr) into the RuO2 lattice is a widely adopted strategy to improve stability. This method effectively mitigates the over-oxidation of Ru species by adjusting the electron density to promote the formation of low-valence Ru. However, the doped metals are easily dissolved due to their thermodynamic instability. On the other hand, replacing Ru atoms with doped metal atoms reduces the number of Ru-O structures, which is detrimental to further improving activity. Non-metallic doping, such as Si, C, and B, can effectively alleviate the above problems.

[0004] The micro / nanostructure of catalysts plays a crucial role in improving the catalytic performance of electrocatalysts. For example, one-dimensional structures with a high aspect ratio can accelerate mass and electron transport during the reaction process, while hollow structures can expose more active sites and provide a larger contact area. Therefore, there is an urgent need for a one-dimensional hollow fiber acidic electrocatalyst that provides efficient and stable catalysis for water electrolysis and proton exchange membrane electrolyzers. Summary of the Invention

[0005] In view of the above situation and to overcome the defects of the prior art, the present invention provides a boron-doped ruthenium dioxide hollow fiber catalyst, its preparation method and application, so as to solve the problems involved in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a boron-doped ruthenium dioxide hollow fiber catalyst, using sodium alginate as raw material, which is spun into calcium alginate fiber through a wet spinning process. The calcium alginate fiber is mixed with boric acid solution, washed and dried to obtain boric acid crosslinked calcium alginate fiber. The boric acid crosslinked calcium alginate fiber is thoroughly mixed with ruthenium trichloride solution and dried to obtain a boric acid crosslinked ruthenium alginate fiber precursor. After pyrolysis treatment, ruthenium ions are converted into ruthenium dioxide nanoparticles, and the boric acid crosslinked alginate fiber is converted into hollow fiber. Boron atoms are incorporated into the ruthenium dioxide lattice to form a boron-doped ruthenium dioxide oxygen evolution reaction electrocatalyst.

[0007] Preparation method of boron-doped ruthenium dioxide hollow fiber catalyst

[0008] 1) Stir the sodium alginate aqueous solution vigorously at room temperature and filter it through a filter cloth to obtain a clear filtrate;

[0009] 2) The clarified filtrate is degassed in the spinning tank and then extruded through a viscose spinneret into a coagulation bath containing a calcium chloride aqueous solution to form nascent fibers.

[0010] 3) The nascent fibers are washed and stretched in distilled water and then dried to obtain calcium alginate fibers;

[0011] 4) Soak the calcium alginate fiber in boric acid solution for a certain period of time, then wash the obtained fiber in distilled water and dry it to obtain boric acid crosslinked calcium alginate fiber.

[0012] 5) Add boric acid crosslinked calcium alginate fiber to hydrochloric acid aqueous solution, ultrasonically soak, and rinse to obtain boric acid crosslinked hydrogen alginate fiber;

[0013] 6) Add the boric acid crosslinked ruthenium alginate fiber obtained in 5) into a mixed solution of ruthenium trichloride, water and ethanol, ultrasonically soak, rinse and dry to obtain boric acid crosslinked ruthenium alginate fiber;

[0014] 7) Boron-doped ruthenium dioxide hollow fibers were obtained by calcining boric acid-crosslinked ruthenium alginate fibers in a tube furnace through a carbonization process.

[0015] Furthermore, the sodium alginate aqueous solution has a mass fraction of 1%, the calcium chloride aqueous solution has a mass fraction of 4%, and the boric acid solution has a mass fraction of 1%.

[0016] Furthermore, in step (5), the concentration of the hydrochloric acid aqueous solution is 1M, and the mass-to-volume ratio of boric acid crosslinked calcium alginate fiber to the hydrochloric acid aqueous solution is 1:100.

[0017] Furthermore, the mass ratio of boric acid crosslinked calcium alginate fiber in 5) to ruthenium trichloride in 6) is 20:1, the concentration of ruthenium trichloride in the water and ethanol mixed solution is 0.5 mg / ml, and the volume ratio of water to ethanol is 3:2.

[0018] Furthermore, the calcination conditions in 7) are heating to 350°C at a heating rate of 2°C / min and holding for 1 hour.

[0019] Application of boron-doped ruthenium dioxide hollow fiber catalyst: application of boron-doped ruthenium dioxide hollow fiber as an electrocatalyst in water electrolysis and proton exchange membrane electrolyzers.

[0020] Furthermore,

[0021] (1) Boron-doped ruthenium dioxide hollow fiber material is used as the anode and cathode catalyst material to assemble a complete water splitting device;

[0022] (2) Boron-doped ruthenium dioxide hollow fiber material is used as an anode catalyst material to assemble a proton exchange membrane electrolyzer with Pt / C catalyst.

[0023] Furthermore, in (1), both the anode and cathode are boron-doped ruthenium dioxide hollow fiber catalysts coated on a 1 cm layer. 2 On the Ti network, the catalyst loading is 1 mg.

[0024] Furthermore, in (2), the anode and cathode are respectively 2 mg·cm⁻¹ -2 Boron-doped ruthenium dioxide hollow fiber catalyst and Pt / C catalyst were sprayed onto polytetrafluoroethylene sheets, with an active surface area of ​​4 cm². 2 .

[0025] Compared with the prior art, the beneficial effects of the present invention are:

[0026] This invention prepares calcium alginate fibers from sodium alginate using a wet spinning process, and then obtains boric acid-crosslinked calcium alginate fibers through boric acid crosslinking. Utilizing the characteristic that ruthenium ions can complex with boric acid-crosslinked calcium alginate fibers, boron-doped ruthenium dioxide hollow fibers are prepared. These boron-doped ruthenium dioxide hollow fibers can be used as high-performance proton exchange membrane electrolyzers and water electrolysis catalysts, exhibiting high catalytic activity and good stability. The raw materials are widely available, require no expensive equipment, and can be prepared in large quantities. Attached Figure Description

[0027] Figure 1 This is a SEM image of boron-doped ruthenium dioxide hollow fiber according to an embodiment of the present invention;

[0028] Figure 2 This is a TEM image of boron-doped ruthenium dioxide hollow fiber according to an embodiment of the present invention;

[0029] Figure 3 This is an HRTEM image of boron-doped ruthenium dioxide hollow fiber according to an embodiment of the present invention;

[0030] Figure 4 This is an OER performance diagram of boron-doped ruthenium dioxide hollow fiber in acidic electrolyte according to an embodiment of the present invention;

[0031] Figure 5 This is a graph showing the OER stability of boron-doped ruthenium dioxide hollow fibers in an acidic electrolyte according to an embodiment of the present invention.

[0032] Figure 6 This is a graph showing the HER performance of boron-doped ruthenium dioxide hollow fibers in an acidic electrolyte according to an embodiment of the present invention.

[0033] Figure 7 This is a diagram illustrating the electrolysis performance of a boron-doped ruthenium dioxide hollow fiber assembly according to an embodiment of the present invention.

[0034] Figure 8 This is a performance diagram of the PEM device assembled from boron-doped ruthenium dioxide hollow fiber Pt / C according to an embodiment of the present invention; Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0036] Example 1:

[0037] A boron-doped ruthenium dioxide hollow fiber catalyst is characterized by: using sodium alginate as raw material, which is spun into calcium alginate fibers via a wet spinning process; mixing the calcium alginate fibers with a boric acid solution, rinsing and drying to obtain boric acid-crosslinked calcium alginate fibers; thoroughly mixing the boric acid-crosslinked calcium alginate fibers with a ruthenium trichloride solution and drying to obtain a boric acid-crosslinked ruthenium alginate fiber precursor; subsequently undergoing pyrolysis treatment, where ruthenium ions are converted into ruthenium dioxide nanoparticles, the boric acid-crosslinked alginate fibers are transformed into hollow fibers, and boron atoms are incorporated into the ruthenium dioxide lattice to form a boron-doped ruthenium dioxide oxygen evolution reaction electrocatalyst.

[0038] Preparation method of boron-doped ruthenium dioxide hollow fiber catalyst

[0039] 1) Prepare a 1% sodium alginate aqueous solution and a 4% calcium chloride aqueous solution. Through a wet spinning process, sodium ions and calcium ions in the sodium alginate eggshell structure exchange to obtain calcium alginate fiber.

[0040] 2) Calcium alginate fiber was mixed with boric acid with a mass fraction of 1% to obtain boric acid crosslinked calcium alginate fiber.

[0041] 3) Take 1g of boric acid crosslinked calcium alginate fiber and mix it with 100mL of 1M HCl. Let it stand under sonication. During this process, hydrogen ions and calcium ions exchange to obtain boric acid crosslinked hydrogen alginate fiber. Then mix the boric acid crosslinked hydrogen alginate fiber with 50mg of ruthenium trichloride, 60mL of water and 40mL of ethanol. Let it stand under sonication. During this process, ruthenium ions and hydrogen ions exchange to obtain boric acid crosslinked ruthenium alginate fiber.

[0042] 4) Place boric acid crosslinked ruthenium alginate fiber in a tube furnace and heat it to 350°C at a heating rate of 2°C / min in an air atmosphere and hold for 1 hour to obtain boron-doped ruthenium dioxide hollow fiber.

[0043] Figure 1 This is a SEM image of boron-doped ruthenium dioxide hollow fibers;

[0044] Figure 2 This is a TEM image of boron-doped ruthenium dioxide hollow fibers;

[0045] Figure 3 This is an HRTEM image of boron-doped ruthenium dioxide hollow fiber;

[0046] Example 2:

[0047] Application of boron-doped ruthenium dioxide hollow fiber catalyst: application of boron-doped ruthenium dioxide hollow fiber as an electrocatalyst in water electrolysis and proton exchange membrane electrolyzers.

[0048] (1) Boron-doped ruthenium dioxide hollow fiber material is used as the anode and cathode catalyst material to assemble a complete water splitting device;

[0049] (2) Boron-doped ruthenium dioxide hollow fiber material is used as an anode catalyst material to assemble a proton exchange membrane electrolyzer with Pt / C catalyst.

[0050] In (1), both the anode and cathode are boron-doped ruthenium dioxide hollow fiber catalysts coated on a 1 cm layer. 2 On the Ti network, the catalyst loading is 1 mg.

[0051] In (2), the anode and cathode are respectively 2 mg·cm -2 Boron-doped ruthenium dioxide hollow fiber catalyst and Pt / C catalyst were sprayed onto polytetrafluoroethylene sheets, with an active surface area of ​​4 cm². 2 .

[0052] Performance testing:

[0053] 1) The OER catalytic activity of the above product in 0.5M H2SO4 electrolyte was tested using an electrochemical workstation. The test results are as follows: Figure 4 As shown, in 0.5M H2SO4 electrolyte, 10mA / cm 2 The overpotential at current density is 220mV, which is better than that of commercial RuO2.

[0054] like Figure 5 As shown, after 60 hours of testing in 0.5M H2SO4 electrolyte, its voltage remained essentially unchanged, demonstrating excellent catalytic stability.

[0055] The HER catalytic activity was tested in 0.5 M H2SO4 electrolyte, and the results are as follows: Figure 6 As stated above, in 0.5M H2SO4 electrolyte, an overpotential of 103mV is required to reach -10mA / cm. 2 The current density.

[0056] 2) The boron-doped ruthenium dioxide hollow fiber material obtained above was used as the anode and cathode catalyst material to assemble a complete water splitting device, and its performance was tested. Figure 7 It can be seen that the boron-doped ruthenium dioxide hollow fiber-assembled total water splitting device obtained in this embodiment operates at 50 mA / cm². 2 The battery voltage at the current density is 1.54V.

[0057] The boron-doped ruthenium dioxide hollow fiber material obtained above was used as the anode catalyst material in combination with a Pt / C catalyst to assemble a proton exchange membrane electrolyzer, and its performance was tested. The results are as follows: Figure 8 As shown, only 1.76V is required to achieve 1A / cm. 2 Its current density is lower than that of commercial RuO2 (1.82V).

[0058] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A boron-doped ruthenium dioxide hollow fiber catalyst, characterized by: The sodium alginate is used as raw material, and is processed into calcium alginate fiber through wet spinning process. The calcium alginate fiber is mixed with boric acid solution, and is washed and dried to obtain boric acid cross-linked calcium alginate fiber. The boric acid cross-linked calcium alginate fiber is mixed with ruthenium trichloride solution, and is dried to obtain boric acid cross-linked ruthenium alginate fiber precursor. After pyrolysis treatment, the ruthenium ions are converted into ruthenium dioxide nanoparticles, the boric acid cross-linked alginate fiber is converted into hollow fiber, and the boron atoms are doped into the ruthenium dioxide lattice to form boron-doped ruthenium dioxide oxygen evolution reaction electrocatalyst.

2. The preparation method of the boron-doped ruthenium dioxide hollow fiber catalyst according to claim 1, characterized in that: 1) the sodium alginate aqueous solution is stirred vigorously at room temperature, and is filtered through filter cloth to obtain a clear filtrate; 2) the clear filtrate is degassed in a spinning tank, and is extruded through a viscose spinneret to a coagulation bath containing calcium chloride aqueous solution to form nascent fiber; 3) the nascent fiber is washed and stretched in distilled water, and is dried to obtain calcium alginate fiber; 4) the calcium alginate fiber is soaked in boric acid solution for a certain time, and the obtained fiber is washed in distilled water, and is dried to obtain boric acid cross-linked calcium alginate fiber; 5) the boric acid cross-linked calcium alginate fiber is added into hydrochloric acid aqueous solution, and is ultrasonically soaked and washed to obtain boric acid cross-linked alginate hydrogen fiber; 6) the boric acid cross-linked alginate hydrogen fiber obtained in 5) is added into a mixed solution of ruthenium trichloride, water and ethanol, and is ultrasonically soaked, washed and dried to obtain boric acid cross-linked ruthenium alginate fiber; 7) the boric acid cross-linked ruthenium alginate fiber is calcined through carbonization process in a tube furnace to obtain boron-doped ruthenium dioxide hollow fiber.

3. The method for preparing the boron-doped ruthenium dioxide hollow fiber catalyst according to claim 2, characterized in that: The mass fraction of the sodium alginate aqueous solution is 1%, and the mass fraction of the calcium chloride aqueous solution is 4%; the mass fraction of the boric acid solution is 1%.

4. The method for preparing the boron-doped ruthenium dioxide hollow fiber catalyst according to claim 2, characterized in that: The concentration of the hydrochloric acid aqueous solution in 5) is 1M, and the mass-volume ratio of the boric acid cross-linked calcium alginate fiber to the hydrochloric acid aqueous solution is 1:

100.

5. The method for preparing the boron-doped ruthenium dioxide hollow fiber catalyst according to claim 2, characterized in that: The mass ratio of the boric acid cross-linked calcium alginate fiber in 5) to the ruthenium trichloride in 6) is 20:1, the concentration of the ruthenium trichloride in the mixed solution of water and ethanol is 0.5mg / ml, and the volume ratio of water to ethanol is 3:

2.

6. The method for preparing the boron-doped ruthenium dioxide hollow fiber catalyst according to claim 2, characterized in that: The calcination condition in 7) is that the temperature is raised to 350℃ at a rate of 2℃ / min and is kept for 1 hour.

7. Use of the boron-doped ruthenium dioxide hollow fiber catalyst according to claim 1, characterized in that: Application of the boron-doped ruthenium dioxide hollow fiber as an electrocatalyst in electrolysis of water and proton exchange membrane electrolyzer.

8. The application of the boron-doped ruthenium dioxide hollow fiber catalyst according to claim 7, characterized in that: (1) the boron-doped ruthenium dioxide hollow fiber material is used as anode and cathode catalyst material to assemble a full water splitting device; (2) the boron-doped ruthenium dioxide hollow fiber material is used as anode catalyst material to assemble a proton exchange membrane electrolyzer combined with Pt / C catalyst.

9. Use of boron-doped ruthenium dioxide hollow fiber catalyst according to claim 8, characterized in that: The anode and cathode in (1) are both boron-doped ruthenium dioxide hollow fiber catalysts coated on 1 cm 2 Ti mesh with a catalyst loading of 1 mg.

10. Use of boron-doped ruthenium dioxide hollow fiber catalyst according to claim 8, characterized in that: The anode and cathode in the (2) are respectively 2 mg·cm -2 of boron-doped ruthenium dioxide hollow fiber catalyst and Pt / C catalyst are sprayed on a polytetrafluoroethylene sheet, and the active surface area is 4 cm 2 .

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