A fluorine-doped ruthenium dioxide catalyst, a preparation method thereof, and an application thereof in proton exchange membrane electrolyzed water

Abstract

The present invention discloses a fluorine-doped ruthenium dioxide catalyst, a preparation method thereof, and an application thereof in proton exchange membrane electrolyzed water. A ruthenium salt and a fluorine salt are dissolved in water and ultrasonically mixed to obtain a mixed solution, then nitrate is added and stirred and mixed, and then freeze-dried to obtain a catalyst precursor, and the fluorine-doped ruthenium dioxide catalyst is obtained by calcination treatment. The catalyst prepared by the present invention effectively modulates the electronic structure of the active center due to the doping of the anion F, and inhibits the excessive oxidation and dissolution of the active center Ru; the highly electronegative F stabilizes the lattice oxygen and inhibits its participation in the reaction and diffusion to the surface; moreover, the doping of F anions changes the surface hydrophilicity of the ruthenium dioxide catalyst and reduces the adverse effects caused by the retention of oxygen bubbles. At the same time, the catalyst exhibits excellent catalytic activity and electrochemical stability in the acidic oxygen evolution reaction, and has the advantages of low cost and good catalytic stability, and can be used as a proton exchange membrane electrolyzed water anode catalyst.

Description

Technical Field

[0001] The present invention belongs to the technical field of proton exchange membrane electrolyzed water catalysts and their preparation, and particularly relates to a fluorine-doped ruthenium dioxide catalyst, a preparation method thereof, and an application in proton exchange membrane electrolyzed water. Background Art

[0002] Proton exchange membrane electrolyzed water (PEMWE) technology can convert renewable clean energies, such as solar energy, wind energy, etc., into hydrogen, which is currently recognized as the most ideal energy carrier. It not only breaks through the inherent intermittency and locality obstacles of energies such as wind energy and solar energy, but also realizes the efficient and carbon-free utilization of renewable energies, thereby effectively solving the increasingly serious problems of environmental pollution and energy shortage.

[0003] However, the electrolyzed water efficiency is limited by the slow kinetics of the anodic oxygen evolution reaction, and a large amount of high-cost and low-reserve iridium (Ir) needs to be used, which seriously hinders the large-scale application of electrolyzed water technology. Therefore, it is urgent to develop an economical and stable PEMWE anodic oxygen evolution electrocatalyst.

[0004] Ruthenium (Ru) has a relatively low price and high intrinsic catalytic activity, and is considered to be the most promising anode catalyst for proton exchange membrane electrolyzed water to replace Ir. At present, although most of the reported ruthenium-based catalysts have excellent catalytic activities, their stability is poor (only dozens of hours), and it is difficult to meet the actual application requirements of proton exchange membrane electrolyzed water technology. Therefore, developing a highly stable ruthenium-based proton exchange membrane electrolyzed water anode catalyst is crucial for reducing the cost of PEMWE technology and realizing its large-scale application.

[0005] The factors affecting the stability of ruthenium-based catalysts mainly include: (1) excessive oxidation and dissolution of ruthenium centers during oxygen evolution, resulting in a reduction in active sites; (2) the participation of lattice oxygen in the catalyst in the oxygen evolution reaction and its removal from the surface, causing structural collapse; (3) the retention of oxygen bubbles shielding the active sites and even peeling off the catalyst.

[0006] Currently, many studies have been conducted to improve the stability of catalysts by addressing the above problems. For example, the rhenium-doped ruthenium dioxide catalyst prepared by the team of Professor Shizhang Qiao effectively inhibits the excessive oxidative dissolution of ruthenium through dynamic electron transfer. At the same time, the Re0.06Ru0.94O2 catalyst exhibits excellent acidic oxygen evolution electrocatalytic activity and stability. (H. Jin, X. Liu, P. An, C. Tang, H. Yu, Q. Zhang, H. J. Peng, L. Gu, Y. Zheng, T. Song, K. Davey, U. Paik, J. Dong, S. Z. Qiao, Dynamic rhenium dopant boosts ruthenium oxide for durable oxygen evolution, Nature Communications 14(1)(2023)354.) The team of Researcher Wei Xing achieved the regulation of the oxygen evolution reaction path by adjusting the charge density of the Ru active center, effectively reducing the degree of participation of lattice oxygen in the reaction, and finally achieving good activity and stability of the catalyst in the membrane electrode system. (Z. Shi, J. Li, Y. Wang, S. Liu, J. Zhu, J. Yang, X. Wang, J. Ni, Z. Jiang, L. Zhang, Y. Wang, C. Liu, W. Xing, J. Ge, Customized reaction route for ruthenium oxide towards stabilized water oxidation in high-performance PEM electrolyzers, Nature Communications 14(1)(2023)843.) The team of Professor Shuangyin Wang prepared an H-doped ruthenium dioxide proton exchange membrane anode oxygen evolution catalyst, which can change the surface hydrophilicity of the catalyst, optimize interfacial mass transfer, effectively avoid surface oxygen retention, and improve the stability of the ruthenium dioxide catalyst. (J. He, W. Chen, H. Gao, Y. Chen, L. Zhou, Y. Zou, R. Chen, L. Tao, S. Wang, Tuning hydrogen binding modes within RuO2 lattice by proton and electron co-doping for active and stable acidic oxygen evolution, Chem Catalysis 2(2022)578-594.)

[0007] Although the above catalyst design can improve the stability of ruthenium-based catalysts, it is still an urgent technical problem to be solved to achieve high stability of ruthenium-based proton exchange membrane electrolytic water anodic oxygen evolution catalysts by a simple and efficient method to solve the problem of poor stability of ruthenium-based catalysts. Summary of the Invention

[0008] The purpose of this part is to outline some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this part, as well as in the abstract and title of the specification of this application, to avoid obscuring the purpose of this part, the abstract of the specification, and the title of the invention, and such simplifications or omissions shall not be used to limit the scope of the present invention.

[0009] In view of the above and / or problems existing in the prior art, the present invention is proposed.

[0010] Therefore, the purpose of the present invention is to overcome the deficiencies in the prior art and provide a preparation method for a fluorine-doped ruthenium dioxide catalyst.

[0011] To solve the above technical problems, the present invention provides the following technical solutions: including,

[0012] A ruthenium salt and a fluorine salt are dissolved in water and ultrasonically mixed to obtain a mixed solution;

[0013] The mixed solution is stirred and mixed with a nitrate and then freeze-dried to obtain a catalyst precursor;

[0014] The catalyst precursor is calcined and post-treated to obtain a fluorine-doped ruthenium dioxide catalyst;

[0015] Among them, the molar ratio of fluorine to ruthenium elements in the mixed solution is 0.02 to 0.78:1.

[0016] As a preferred scheme of the preparation method of the fluorine-doped ruthenium dioxide catalyst of the present invention, among them: the molar ratio of ruthenium element in the mixed solution to NO3 in the nitrate - is 0.006 to 0.034:1.

[0017] As a preferred scheme of the preparation method of the fluorine-doped ruthenium dioxide catalyst of the present invention, among them: the ruthenium salt includes one of ruthenium chloride, potassium chlororuthenate, and ruthenium acetate.

[0018] As a preferred scheme of the preparation method of the fluorine-doped ruthenium dioxide catalyst of the present invention, among them: the fluorine salt includes one of sodium fluoride, potassium fluoride, and ammonium fluoride.

[0019] As a preferred scheme of the preparation method of the fluorine-doped ruthenium dioxide catalyst of the present invention, among them: the time of ultrasonic mixing is 20 to 30 min.

[0020] As a preferred embodiment of the preparation method of the fluorine-doped ruthenium dioxide catalyst of the present invention, wherein: the stirring speed of the stirring and mixing is 400-600 rpm, and the stirring time is 30-60 min.

[0021] As a preferred embodiment of the preparation method of the fluorine-doped ruthenium dioxide catalyst of the present invention, wherein: the time of freeze-drying is 36-72 h.

[0022] As a preferred embodiment of the preparation method of the fluorine-doped ruthenium dioxide catalyst of the present invention, wherein: the calcination is carried out in an air atmosphere, wherein the heating rate of the calcination is 5 °C / min, the calcination temperature is 300-450 °C, and the calcination time is 30-60 min.

[0023] Another object of the present invention is to provide a fluorine-doped ruthenium dioxide catalyst and its application in proton exchange membrane electrolyzed water.

[0024] Advantages of the present invention:

[0025] In the F-doped ruthenium dioxide catalyst prepared by the present invention, the electronic structure of the active center is effectively modulated by the anion F doping, and the excessive oxidation and dissolution of the active center Ru are inhibited; the highly electronegative F stabilizes the lattice oxygen and inhibits its participation in the reaction and diffusion to the surface; and the F anion doping changes the surface hydrophilicity of the ruthenium dioxide catalyst, reducing the adverse effects caused by the retention of oxygen bubbles.

[0026] The catalyst of the present invention shows excellent catalytic activity and electrochemical stability in the acidic oxygen evolution reaction, has the advantages of low cost and good catalytic stability, and has broad prospects as an anode catalyst for proton exchange membrane electrolyzed water. Description of the drawings

[0027] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to these drawings. Among them:

[0028] Figure 1 It is the transmission electron microscope characterization diagram of the fluorine-doped ruthenium dioxide catalyst prepared in Example 1 of the present invention.

[0029] Figure 2 It is the X-ray diffraction characterization diagram of the fluorine-doped ruthenium dioxide catalyst prepared in Example 1 of the present invention.

[0030] [[ID=SS]] Figure 3This is the elemental mapping analysis result diagram of the fluorine-doped ruthenium dioxide catalyst prepared in Example 1 of the present invention.

[0031] Figure 4 This is the linear sweep voltammetry test result diagram of the fluorine-doped ruthenium dioxide catalyst prepared in Example 1 of the present invention in a 0.5 mol / L sulfuric acid solution.

[0032] Figure 5 This is the chronopotentiometry test result diagram of the fluorine-doped ruthenium dioxide catalyst prepared in Example 1 of the present invention at a current density of 10 mA cm -2 in a 0.5 mol / L sulfuric acid solution. Detailed implementation manners

[0033] In order to make the above objects, features and advantages of the present invention more obvious and understandable, the following describes the detailed implementation manners of the present invention in conjunction with the embodiments of the specification.

[0034] In the following description, many specific details are set forth to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Those skilled in the art can make similar generalizations without departing from the connotation of the present invention. Therefore, the present invention is not limited by the specific embodiments disclosed below.

[0035] Secondly, the so-called "one embodiment" or "embodiment" herein refers to a specific feature, structure or characteristic that can be included in at least one implementation manner of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment that excludes other embodiments.

[0036] Example 1

[0037] This embodiment provides a preparation method of a fluorine-doped ruthenium dioxide catalyst, specifically as follows:

[0038] Weigh 50 mg of ruthenium chloride and 6 mg of sodium fluoride and dissolve them in 5 mL of deionized water. Ultrasonically mix for 30 min to obtain a mixed solution, where the molar ratio of fluorine to ruthenium elements is 0.59:1;

[0039] Add 3 g of sodium nitrate to the mixed solution so that the molar ratio of ruthenium element in the mixed solution to NO3 in the nitrate - is 0.007:1. Then stir at a speed of 500 rpm for 60 min and freeze-dry for 48 h to obtain a catalyst precursor, which is a black solid;

[0040] The catalyst precursor was placed in a tubular furnace and calcined in an air atmosphere at a heating rate of 5 °C / min, a calcination temperature of 350 °C, and a calcination time of 45 min. After natural cooling to room temperature, the solid was washed in an aqueous solution, filtered by suction, and then dried in an oven to obtain a fluorine (F)-doped ruthenium dioxide catalyst.

[0041] The F-doped ruthenium dioxide proton exchange membrane electrolytic water anode catalyst prepared in this example was characterized by transmission electron microscopy, and the results are as Figure 1 shown. The obtained catalyst presented a wrinkled nanosheet structure, which could expose more active sites and effectively improve the utilization rate of the noble metal Ru.

[0042] Figure 2 This is the X-ray diffraction characterization result of the catalyst in this example. It can be seen that the prepared catalyst has a rutile phase structure. Figure 3 From the elemental Mapping analysis result of

[0043] Performance test

[0044] The F-doped ruthenium dioxide proton exchange membrane electrolytic water anode catalyst of Example 1 was subjected to linear sweep voltammetry test in a 0.5 mol / L sulfuric acid solution, and the results are as Figure 4 shown. The F-doped ruthenium dioxide proton exchange membrane electrolytic water anode catalyst had an overpotential of 206 mV at a current density of 10 mA cm cata. cm -2 at a loading of 0.5 mg, showing better activity than the commercial RuO2 catalyst. -2 At a current density of 10 mA cm

[0045] The F-doped ruthenium dioxide proton exchange membrane electrolytic water anode catalyst of Example 1 was subjected to chronopotentiometry test in a 0.5 mol / L sulfuric acid solution at a current density of 10 mA cm -2 , and the results are as Figure 5 shown. The F-doped ruthenium dioxide proton exchange membrane electrolytic water anode catalyst (loading 1.0 mg cata. cm -2 ) had a potential decay rate of only 8 μV h -1 during the 500 h chronopotentiometry test, showing better stability than the commercial RuO2 catalyst, indicating that F doping is beneficial to improving the stability of the ruthenium dioxide catalyst.

[0046] Example 2

[0047] The difference between this example and Example 1 is that the molar ratio of fluorine to ruthenium elements was adjusted to 0.10:1. Specifically:

[0048] Weigh 50 mg of ruthenium chloride and 1 mg of sodium fluoride, dissolve them in 5 mL of deionized water, and ultrasonically mix for 30 min to obtain a mixed solution;

[0049] Add 3 g of sodium nitrate to the mixed solution, stir at a speed of 500 rpm for 60 min, and then freeze-dry for 48 h to obtain a catalyst precursor, which is a black solid;

[0050] Place the catalyst precursor in a tube furnace, calcine it in an air atmosphere, with a heating rate of 5 °C / min, a calcination temperature of 350 °C, and a calcination time of 45 min. After naturally cooling to room temperature, wash the solid in an aqueous solution, filter it by suction, and then dry it in an oven to obtain a fluorine (F)-doped ruthenium dioxide catalyst.

[0051] Perform three-electrode activity and stability tests on the F-doped ruthenium dioxide catalyst prepared in this example, and the results are comparable to those of Example 1.

[0052] Example 3

[0053] The difference between this example and Example 1 is that the calcination temperature is adjusted to 300 °C. Specifically:

[0054] Weigh 50 mg of ruthenium chloride and 6 mg of sodium fluoride, dissolve them in 5 mL of deionized water, and ultrasonically mix for 30 min to obtain a mixed solution;

[0055] Add 3 g of sodium nitrate to the mixed solution, stir at a speed of 500 rpm for 60 min, and then freeze-dry for 48 h to obtain a catalyst precursor, which is a black solid;

[0056] Place the catalyst precursor in a tube furnace, calcine it in an air atmosphere, with a heating rate of 5 °C / min, a calcination temperature of 300 °C, and a calcination time of 45 min. After naturally cooling to room temperature, wash the solid in an aqueous solution, filter it by suction, and then dry it in an oven to obtain a fluorine (F)-doped ruthenium dioxide catalyst.

[0057] Perform three-electrode activity and stability tests on the F-doped ruthenium dioxide catalyst prepared in this example, and the results are comparable to those of Example 1.

[0058] Example 4

[0059] The difference between this example and Example 1 is that the calcination time is adjusted to 30 min. Specifically:

[0060] Weigh 50 mg of ruthenium chloride and 6 mg of sodium fluoride, dissolve them in 5 mL of deionized water, and ultrasonically mix for 30 min to obtain a mixed solution;

[0061] Add 3 g of sodium nitrate to the mixed solution, stir at a speed of 500 rpm for 60 min, and then freeze-dry for 48 h to obtain a catalyst precursor, which is a black solid;

[0062] The catalyst precursor was placed in a tube furnace and calcined in an air atmosphere at a heating rate of 5 °C / min, a calcination temperature of 350 °C, and a calcination time of 30 min. After natural cooling to room temperature, the solid was washed in an aqueous solution, filtered by suction, and then dried in an oven to obtain a fluorine (F)-doped ruthenium dioxide catalyst.

[0063] The three-electrode activity and stability of the F-doped ruthenium dioxide catalyst prepared in this example were tested, and the results were comparable to those of Example 1.

[0064] Example 5

[0065] The difference between this example and Example 1 was that the calcination time was adjusted to 60 min. Specifically:

[0066] 50 mg of ruthenium chloride and 6 mg of sodium fluoride were weighed and dissolved in 5 mL of deionized water, and ultrasonically mixed for 30 min to obtain a mixed solution;

[0067] 3 g of sodium nitrate was added to the mixed solution and stirred at a speed of 500 rpm for 60 min, and then freeze-dried for 48 h to obtain a catalyst precursor, which was a black solid;

[0068] The catalyst precursor was placed in a tube furnace and calcined in an air atmosphere at a heating rate of 5 °C / min, a calcination temperature of 350 °C, and a calcination time of 60 min. After natural cooling to room temperature, the solid was washed in an aqueous solution, filtered by suction, and then dried in an oven to obtain a fluorine (F)-doped ruthenium dioxide catalyst.

[0069] The three-electrode activity and stability of the F-doped ruthenium dioxide catalyst prepared in this example were tested, and the results were comparable to those of Example 1.

[0070] Example 6

[0071] The difference between this example and Example 1 was that the molar ratio of ruthenium element to nitrate radical in the mixed solution was adjusted to 0.014:1, and the rest of the preparation process was referred to Example 1. Specifically:

[0072] 100 mg of ruthenium chloride and 12 mg of sodium fluoride were weighed and dissolved in 10 mL of deionized water, and ultrasonically mixed for 30 min to obtain a mixed solution;

[0073] 3 g of sodium nitrate was added to the mixed solution and stirred at a speed of 500 rpm for 60 min, and then freeze-dried for 48 h to obtain a catalyst precursor, which was a black solid;

[0074] The catalyst precursor was placed in a tube furnace and calcined in an air atmosphere at a heating rate of 5 °C / min, a calcination temperature of 350 °C, and a calcination time of 45 min. After natural cooling to room temperature, the solid was washed in an aqueous solution, filtered by suction, and then dried in an oven to obtain a fluorine (F)-doped ruthenium dioxide catalyst.

[0075] The three-electrode activity and stability of the F-doped ruthenium dioxide catalyst prepared in this example were tested, and the results were comparable to those of Example 1.

[0076] Comparative Example 1

[0077] The difference between this comparative example and Example 1 was that the molar ratio of fluorine to ruthenium elements was adjusted to 0.79:1. Specifically:

[0078] 50 mg of ruthenium chloride and 8 mg of sodium fluoride were weighed and dissolved in 5 mL of deionized water, and ultrasonically mixed for 30 min to obtain a mixed solution;

[0079] 3 g of sodium nitrate was added to the mixed solution and stirred at a speed of 500 rpm for 60 min, and then freeze-dried for 48 h to obtain a catalyst precursor, which was a black solid;

[0080] The catalyst precursor was placed in a tube furnace and calcined in an air atmosphere at a heating rate of 5 °C / min, a calcination temperature of 350 °C, and a calcination time of 45 min. After natural cooling to room temperature, the solid was washed in an aqueous solution, filtered by suction, and then dried in an oven to obtain a fluorine (F)-doped ruthenium dioxide catalyst.

[0081] The F-doped ruthenium dioxide catalyst prepared in this comparative example had an overpotential of 253 mV at a current density of 10 mA cm cata. cm -2 at a loading of 0.5 mg, which was 47 mV higher than that of Example 1. -2

[0082] Comparative Example 2

[0083] The difference between this comparative example and Example 1 was that the molar ratio of fluorine to ruthenium elements was adjusted to 0:1, that is, no F was added. Specifically:

[0084] 50 mg of ruthenium chloride was weighed and dissolved in 5 mL of deionized water, and ultrasonically mixed for 30 min to obtain a mixed solution;

[0085] 3 g of sodium nitrate was added to the mixed solution and stirred at a speed of 500 rpm for 60 min, and then freeze-dried for 48 h to obtain a catalyst precursor, which was a black solid;

[0086] ​Place the catalyst precursor in a tubular furnace and calcine it in an air atmosphere at a heating rate of 5 °C / min, a calcination temperature of 350 °C, and a calcination time of 45 min. After natural cooling to room temperature, wash the solid in an aqueous solution, filter it by suction, and then dry it in an oven to obtain a ruthenium dioxide catalyst without F.

[0087] The ruthenium dioxide catalyst without F doping prepared in this comparative example has a loading of 0.5 mg cata. cm -2 The overpotential at a current density of 10 mA / cm -2 is 233 mV, which is 27 mV higher than that in Example 1. In addition, its stability is much lower than that in Example 1. At a current density of 10 mA / cm -2 the potential required increases sharply after 25 h, indicating that the catalyst is rapidly deactivated.

[0088] Comparative Example 3

[0089] The difference between this comparative example and Example 1 is that the calcination temperature is adjusted to 550 °C. Specifically:

[0090] Weigh 50 mg of ruthenium chloride and 6 mg of sodium fluoride, dissolve them in 5 mL of deionized water, and ultrasonically mix for 30 min to obtain a mixed solution;

[0091] Add 3 g of sodium nitrate to the mixed solution, stir at a speed of 500 rpm for 60 min, and then freeze-dry for 48 h to obtain the catalyst precursor, which is a black solid;

[0092] Place the catalyst precursor in a tubular furnace and calcine it in an air atmosphere at a heating rate of 5 °C / min, a calcination temperature of 550 °C, and a calcination time of 45 min. After natural cooling to room temperature, wash the solid in an aqueous solution, filter it by suction, and then dry it in an oven to obtain a fluorine (F)-doped ruthenium dioxide catalyst.

[0093] The F-doped ruthenium dioxide catalyst prepared in this comparative example has a loading of 0.5 mg cata. cm -2 Under the three-electrode test conditions, its current density is difficult to reach 10 mA / cm -2 , and its activity is much lower than that in Example 1.

[0094] Comparative Example 4

[0095] The difference between this comparative example and Example 1 is that the calcination temperature is adjusted to 275 °C. Specifically:

[0096] Weigh 50 mg of ruthenium chloride and 6 mg of sodium fluoride, dissolve them in 5 mL of deionized water, and ultrasonically mix for 30 min to obtain a mixed solution;

[0097] 3 g of sodium nitrate was added to the mixed solution, and the mixture was stirred at 500 rpm for 60 min and then freeze-dried for 48 h to obtain a catalyst precursor, which was a black solid;

[0098] The catalyst precursor was placed in a tube furnace and calcined in an air atmosphere at a heating rate of 5 °C / min, a calcination temperature of 275 °C, and a calcination time of 45 min. After natural cooling to room temperature, the solid was washed in an aqueous solution, filtered by suction, and then dried in an oven to obtain a fluorine (F)-doped ruthenium dioxide catalyst.

[0099] The F-doped ruthenium dioxide catalyst prepared in this comparative example had an overpotential of 220 mV at a loading of 0.5 mg cata. cm -2 and a current density of 10 mA cm -2 at which was 14 mV higher than that in Example 1.

[0100] Comparative Example 5

[0101] The difference between this comparative example and Example 1 was that the calcination time was adjusted to 15 min. Specifically:

[0102] 50 mg of ruthenium chloride and 6 mg of sodium fluoride were weighed and dissolved in 5 mL of deionized water, and the mixture was ultrasonically mixed for 30 min to obtain a mixed solution;

[0103] 3 g of sodium nitrate was added to the mixed solution, and the mixture was stirred at 500 rpm for 60 min and then freeze-dried for 48 h to obtain a catalyst precursor, which was a black solid;

[0104] The catalyst precursor was placed in a tube furnace and calcined in an air atmosphere at a heating rate of 5 °C / min, a calcination temperature of 350 °C, and a calcination time of 15 min. After natural cooling to room temperature, the solid was washed in an aqueous solution, filtered by suction, and then dried in an oven to obtain a fluorine (F)-doped ruthenium dioxide catalyst.

[0105] The F-doped ruthenium dioxide catalyst prepared in this comparative example had an overpotential of 218 mV at a loading of 0.5 mg cata. cm -2 and a current density of 10 mA cm -2 at which was 12 mV higher than that in Example 1.

[0106] Comparative Example 6

[0107] The difference between this comparative example and Example 1 was that the calcination time was adjusted to 65 min. Specifically:

[0108] 50 mg of ruthenium chloride and 6 mg of sodium fluoride were weighed and dissolved in 5 mL of deionized water, and the mixture was ultrasonically mixed for 30 min to obtain a mixed solution;

[0109] 3 g of sodium nitrate was added to the mixed solution, and the mixture was stirred at a speed of 500 rpm for 60 min and then freeze-dried for 48 h to obtain a catalyst precursor, which was a black solid;

[0110] The catalyst precursor was placed in a tubular furnace and calcined in an air atmosphere at a heating rate of 5 °C / min, a calcination temperature of 350 °C, and a calcination time of 65 min. After natural cooling to room temperature, the solid was washed in an aqueous solution, filtered by suction, and then placed in an oven for drying to obtain a fluorine (F)-doped ruthenium dioxide catalyst.

[0111] The F-doped ruthenium dioxide catalyst prepared in this comparative example had a loading of 0.5 mg cata. cm -2 and the overpotential at a current density of 10 mA cm -2 was 227 mV, which was 21 mV higher than that in Example 1.

[0112] In summary, the F-doped ruthenium dioxide catalyst prepared in the present invention effectively modulates the electronic structure of the active center due to the doping of anion F, inhibits the excessive oxidation and dissolution of the active center Ru; the highly electronegative F stabilizes the lattice oxygen, inhibits its participation in the reaction and diffusion to the surface; and, the doping of F anions changes the surface hydrophilicity of the ruthenium dioxide catalyst, reduces the adverse effects caused by the retention of oxygen bubbles; it exhibits excellent catalytic activity and electrochemical stability in the acidic oxygen evolution reaction, has the advantages of low cost and good catalytic stability, and has broad prospects as a proton exchange membrane electrolytic water anode catalyst.

[0113] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the spirit and scope of the technical solutions of the present invention, and they should all be covered by the scope of the claims of the present invention.

Claims

1. A preparation method of a fluorine-doped ruthenium dioxide catalyst for proton exchange membrane electrolysis of water, characterized in that: including, dissolve a ruthenium salt and a fluoride salt in deionized water, and ultrasonically mix to obtain a mixed solution; stir and mix the mixed solution with sodium nitrate, and then freeze-dry to obtain a catalyst precursor; calcine the catalyst precursor and perform post-treatment to obtain a fluorine-doped ruthenium dioxide catalyst; wherein, the molar ratio of fluorine to ruthenium elements in the mixed solution is 0.02~0.78:1; the calcination is carried out in an air atmosphere, wherein the heating rate of calcination is 5 °C / min, the calcination temperature is 300~450 °C, and the calcination time is 30~60 min.

2. The preparation method of the fluorine-doped ruthenium dioxide catalyst according to claim 1, wherein: The molar ratio of ruthenium element to NO3 in nitrate in the mixed solution - is 0.006 to 0.034:

1.

3. The preparation method of the fluorine-doped ruthenium dioxide catalyst according to claim 1, characterized in that: The ruthenium salt includes one of ruthenium chloride, potassium chlororuthenate, and ruthenium acetate.

4. The preparation method of the fluorine-doped ruthenium dioxide catalyst according to claim 1, characterized in that: The fluoride salt includes one of sodium fluoride, potassium fluoride, and ammonium fluoride.

5. The preparation method of the fluorine-doped ruthenium dioxide catalyst according to claim 1, characterized in that: The time of ultrasonic mixing is 20~30 min.

6. The preparation method of the fluorine-doped ruthenium dioxide catalyst according to claim 1, characterized in that: The stirring speed of the stirring and mixing is 400~600 rpm, and the stirring time is 30~60 min.

7. The preparation method of the fluorine-doped ruthenium dioxide catalyst according to claim 1, characterized in that: The time of freeze-drying is 36~72 h.

8. A fluorine-doped ruthenium dioxide catalyst prepared by the preparation method according to any one of claims 1~7.

9. Application of the fluorine-doped ruthenium dioxide catalyst according to claim 8 in proton exchange membrane electrolysis of water.

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