Porous carbon supported low-oxygen coordination nanooxide catalysts, methods of making and using the same

Abstract

The application discloses a kind of porous carbon load low oxygen coordination nano-oxide catalyst and its preparation method and application.The active component of catalyst is low oxygen coordination nano-oxide, and is loaded on the surface of porous carbon carrier.The preparation method is: acetylacetone salt is selected to be dissolved in anhydrous ethanol or deionized water to obtain metal salt solution, which is fully stirred and mixed with porous carbon carrier, and the solid is ground after solvent volatilization to obtain catalyst precursor, finally, the precursor is placed in a tube furnace, and the catalyst is obtained by high-temperature treatment under the protection of inert gas.The catalyst can be used as a cathode catalyst for alkaline fuel cell, and is used for oxygen reduction reaction in alkaline electrolyte system, and has excellent catalytic activity and cycle stability.The preparation method is simple and efficient, has good repeatability, low cost, easy to mass industrial production, and has good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell technology, specifically to porous carbon-supported low-oxygen coordination nano-oxide catalysts, their preparation methods, and applications. Background Technology

[0002] With the increasing depletion of traditional fossil fuels and the environmental pollution caused by energy utilization, the global energy sector is accelerating the research and development of clean and renewable energy sources and efficient energy conversion technologies. Alkaline fuel cells (AFCs), as one of the most promising clean energy conversion devices, have attracted much attention in the energy conversion field due to their significant advantages such as high energy conversion efficiency, environmental friendliness, and mild operating conditions. However, the overall performance improvement of alkaline fuel cells is limited by the cathode oxygen reduction reaction (ORR), whose inherently slow kinetics have become the core bottleneck restricting breakthrough improvements in AFC performance. Currently, Pt-based materials are the most active catalysts in the ORR, but Pt is expensive and extremely scarce in the Earth's crust, a key issue that greatly hinders the commercialization of alkaline fuel cells. Therefore, developing inexpensive non-Pt-based ORR catalysts that combine high catalytic activity and high stability is of significant practical and strategic value for promoting the large-scale commercial application and sustainable development of alkaline fuel cells.

[0003] The ORR reaction in alkaline fuel cells takes place in an alkaline medium, which reduces the corrosion requirements on the catalyst compared to acidic media. However, the catalyst still needs to possess both high catalytic activity and excellent electrochemical stability. Among many non-Pt-based materials, transition metal oxides are highly promising ORR catalyst candidates due to their wide availability, low cost, excellent chemical stability (strong corrosion resistance in alkaline media), and tunable d-orbital electronic structure, which can provide sufficient active sites for the ORR reaction. Numerous studies have shown that the ORR catalytic performance of transition metal oxides is closely related to their surface oxygen coordination environment, a correlation confirmed by experimental characterization and theoretical calculations in multiple publications. The d orbitals of transition metals contain unfilled electrons, and the number of oxygen coordination sites on the oxide surface can directly regulate the d-orbital electron cloud density, thus affecting the number of surface active sites and catalytic activity. A low-oxygen coordination environment can promote the formation of a large number of unsaturated coordinated metal sites on the oxide surface. These sites can effectively weaken the O=O bond energy of O2 molecules, promote O2 adsorption and dissociation activation, and optimize ORR reaction intermediates (such as OOH). - The adsorption strength of oxygen (O2) accelerates reaction kinetics. Based on this characteristic, designing and constructing a low-oxygen coordination environment has become a key research direction for improving the ORR catalytic performance of transition metal oxides.

[0004] However, in existing research, it is difficult to form stable low-oxygen coordination structures on the surface of transition metal oxides, and these low-oxygen coordination sites are prone to reconstruction or loss during the reaction process. As a result, their catalytic activity and cycle stability still fall short of the requirements for practical applications of alkaline fuel cells. Therefore, developing transition metal oxide-based ORR catalysts that can construct stable low-oxygen coordination structures and combine high performance with low cost has become a current research focus in this field.

[0005] Shan et al. prepared ZrO2-Cu using a two-step sulfidation-etching method. 1.93 The S / C catalyst (Shan, S.; Du, L.; Cheng, S.; Yin, Y.; Wu, J.; Wang, W., Materials Chemistry and Physics, 2025, 338: 130688.) exhibits an ORR onset potential of 0.90 V vs. RHE in a 0.1 M KOH alkaline electrolyte, but its ORR half-wave potential is 0.71 V vs. RHE. Compared with commercial Pt / C catalysts, its catalytic activity still shows a significant gap. Furthermore, its preparation process is relatively complex, making large-scale production difficult.

[0006] Cui et al. synthesized an α-MnO2 catalyst via hydrothermal synthesis using potassium permanganate and manganese sulfate as raw materials (Cui B, Zhu Y, Hu T, et al., Applied Surface Science, 2025, 709: 163823.). The catalyst exhibited an ORR onset potential of 0.83 V vs. RHE and an ORR half-wave potential of 0.78 V vs. RHE in a 0.1 M KOH alkaline electrolyte. However, its catalytic activity still showed a significant gap compared to commercial Pt / C catalysts. Furthermore, regarding stability, after 10,000 cycles of cyclic voltammetry, the electrochemical activity retention rate of this α-MnO2 catalyst was only 71%, indicating that active sites are easily lost and structural stability is insufficient during long-term cycling, further limiting its prospects for large-scale application.

[0007] Yang et al. constructed a CoMn2O4 / C catalyst using a simplified hydrothermal method (Yang Y, Xiong Y, Holtz ME, et al., Proceedings of the National Academy of Sciences, 2019, 116 (49):24425-24432). The catalyst exhibited an ORR onset potential of 0.93 V vs. RHE and an ORR half-wave potential of 0.855 V vs. RHE in 1 M KOH alkaline electrolyte, demonstrating activity levels comparable to commercial Pt / C catalysts. However, the catalyst exhibited significant shortcomings in long-term operational stability. After 10,000 cyclic voltammetry cycles, its ORR half-wave potential showed a marked decrease of 30 mV. The core cause of this performance degradation was the dissolution of Mn during cycling, making it difficult for the catalyst to meet the actual operating conditions required for long-term alkaline fuel cell operation.

[0008] Wang et al. prepared a ZrO2 / NC catalyst using a low-temperature carbonization sol-gel method combined with etching (Wang M, Zheng H, Dong Y, et al., Applied Physics Letters, 2022, 120(26):261903.). The catalyst exhibited an ORR onset potential of 0.95 V vs. RHE and an ORR half-wave potential of 0.815 V vs. RHE in a 0.1 M KOH alkaline electrolyte. However, the catalyst preparation process utilizes highly corrosive hydrofluoric acid, which can easily corrode equipment during preparation and wastewater treatment, and also poses certain environmental risks.

[0009] Chinese patent (publication number: CN109718823A) discloses an N-doped TiO2 / C composite material, its preparation method, and its application. This method mainly involves a one-step hydrothermal bonding of carbon materials and TiO2, followed by high-temperature treatment to alter the crystal structure of TiO2. The catalyst reported in this patent exhibits a half-wave potential of 0.565 V vs. RHE in 0.1 M NaOH electrolyte, showing a significant performance gap compared to commercial Pt / C catalysts.

[0010] Chinese patent (publication number: CN115722242A) discloses a method for preparing a mesoporous carbon nanocomposite catalytic material simultaneously loaded with transition metal single atoms and metallic nanoparticles in one step. This material is produced using sodium alginate, a natural high-molecular-weight extracted from brown algae, as a raw material. The method involves spontaneous co-crosslinking of sodium alginate with various multivalent metal ions to form a gel, followed by freeze-drying and high-temperature carbonization. The catalyst exhibits a half-wave potential of 0.95 V vs. RHE in 0.1 M HClO4 electrolyte. While this method has broad applicability, particle aggregation is highly likely to occur during synthesis if the carbon support is damaged or the interaction between the active component and the support weakens, leading to the loss of active sites. Furthermore, the catalytic material described in this patent is primarily intended for use in acidic membrane fuel cells, and its performance testing and practical application in alkaline fuel cell systems have not yet been addressed.

[0011] Chinese patent (publication number: CN103623807A) discloses a method for preparing a novel doped nano-zirconia catalyst. The method primarily uses porous, high-temperature resistant zirconia as a support, adds nitrate-chromium nitrate, and prepares monodisperse nanoparticles using a gel-sol method. Further, monodisperse self-assembled doped nano-zirconia is prepared via self-assembly. The catalyst described in this patent is mainly applied to the catalytic degradation of carbohydrates such as sugars, and its application in the oxygen reduction reaction of alkaline fuel cells has not yet been extended to related research.

[0012] In summary, although there have been many reports on the preparation and application of nano-oxides, no preparation scheme for porous carbon-supported nano-oxide catalysts that can stably construct low-oxygen coordination structures, possess both high performance and low cost, and are suitable for oxygen reduction reactions in alkaline fuel cells has yet been found in existing technologies and related research reports. Summary of the Invention

[0013] The purpose of this invention is to overcome the shortcomings of existing technologies and disclose a porous carbon-supported low-oxygen coordination nano-oxide catalyst, its preparation method, and its application. Addressing the limitations of current alkaline fuel cell catalysts, such as high cost and difficulty in large-scale production of Pt-based catalysts, and the inability of existing non-precious metal oxide catalysts to form stable low-oxygen coordination structures and insufficient catalytic activity and long-term stability, this invention proposes a simple, efficient, low-cost, and large-scale production-suitable method for preparing porous carbon-supported low-oxygen coordination nano-oxide catalysts. This method can form stable low-oxygen coordination active sites to optimize oxygen reduction reaction performance, which is of great significance for promoting the commercial development of alkaline fuel cells.

[0014] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a porous carbon-supported low-oxygen coordination nano-oxide catalyst, comprising dissolving acetylacetone salt in deionized water or anhydrous ethanol solution to prepare a metal salt solution, then adding the metal salt solution to a porous carbon support and mixing it, obtaining a precursor by heating and stirring, and then placing the precursor into a tube furnace and calcining it in an inert gas atmosphere to finally obtain a porous carbon-supported low-oxygen coordination nano-oxide alkaline fuel cell catalyst.

[0015] Furthermore, the acetylacetone salt includes any one or more of the following: scandium acetylacetone, yttrium acetylacetone, zirconium acetylacetone, titanium acetylacetone, hafnium acetylacetone, vanadium acetylacetone, niobium acetylacetone, tantalum acetylacetone, chromium acetylacetone, molybdenum acetylacetone, and tungsten acetylacetone.

[0016] Furthermore, the acetylacetone salt is dissolved in water or ethanol, wherein the concentration of the acetylacetone salt in the metal salt solution is 0.01-1 mol / L.

[0017] Furthermore, the porous carbon support includes any one or more of ZIF, MOF, COF and their derivative supports.

[0018] Furthermore, the metal salt solution is added to the porous carbon support and mixed by stirring or sonication for 0.5-3 hours.

[0019] Furthermore, the precursor obtained by heating and stirring is obtained by using a magnetic heating stirrer, water bath, oil bath or sand bath to evaporate the solvent. The heating temperature is 70-120℃ and the heating time is 3-6 h.

[0020] Furthermore, the precursor is placed in a tube furnace, and the calcination atmosphere is argon or nitrogen. The calcination temperature is 700-1100℃, and the calcination time is 0.5-5 h.

[0021] Furthermore, the nano-oxides include any one or more of nano-scandium oxide, nano-yttrium oxide, nano-titanium oxide, nano-zirconium oxide, nano-hafnium oxide, nano-vanadium oxide, nano-niobium oxide, nano-tantalum oxide, nano-molybdenum oxide, and nano-tungsten oxide.

[0022] The catalyst prepared by the method of this invention is different from that of the prior art. Therefore, the catalyst of this invention is also within the scope of protection of this invention. The final particle size of the low oxygen coordination nano-oxide is 1-20 nm.

[0023] The catalyst obtained by this invention can be used as a cathode catalyst in alkaline fuel cells. It participates in the oxygen reduction reaction in alkaline electrolyte. Due to the stable low-oxygen coordination structure formed on its surface, it exhibits good catalytic activity and long-term stability, and has excellent ORR catalytic performance.

[0024] Compared with existing technologies, the porous carbon-supported low-oxygen coordination nano-oxide catalyst and its preparation method of the present invention have the following advantages: (1) This invention proposes a method for preparing porous carbon-supported low-oxygen coordinated nano-oxides. The prepared low-oxygen coordinated oxide nanoparticles are uniformly distributed and have a particle size of less than 5 nm, which is beneficial for exposing a large number of active sites. The introduction of porous carbon support endows the catalyst with good conductivity. The above advantages make this material suitable for use as an alkaline fuel cell catalyst, which is beneficial for improving the current density of the catalyst.

[0025] (2) The method provided by the present invention can easily prepare different porous carbon-supported low-oxygen coordination nano-oxide catalysts. It is a universal preparation method that is suitable for large-scale industrial production.

[0026] (3) The catalyst prepared by the preparation method provided by the present invention can carry out oxygen reduction reaction in alkaline electrolyte. Thanks to the rich and tunable d-band electron structure of the oxide itself, the catalyst exhibits excellent catalytic activity. The ORR onset potential of the catalyst is 0.94 V vs. RHE, and the ORR half-wave potential is 0.85 V vs. RHE. It is one of the best performing oxide ORR catalysts in existing alkaline media. Attached Figure Description

[0027] Figure 1 ZrO prepared in Example 1 2-X Transmission electron microscopy (TEM) image of / MOF-C.

[0028] Figure 2 ZrO prepared in Example 1 2-X High-resolution transmission electron microscopy (HR-TEM) image of MOF-C.

[0029] Figure 3 ZrO prepared in Example 1 2-X X-ray diffraction pattern of MOF-C.

[0030] Figure 4 Zr film, ZrO 2-X Extended X-ray fine structure absorption spectra (EXAFS) of MOF-C and commercial ZrO2.

[0031] Figure 5 ZrO prepared in Example 1 2-X Oxygen reduction linear polarization curves of / MOF-C and commercial Pt / C catalysts in alkaline media after removing the nitrogen background.

[0032] Figure 6 ZrO prepared in Example 12-X Electrochemical activity retention rate of MOF-C after 40,000 cycles of constant voltage discharge test.

[0033] Figure 7 ZrO prepared in Example 1 2-X The oxygen reduction linear polarization curve of / MOF-C after 40,000 cycles of constant voltage discharge test.

[0034] Figure 8 The CrO prepared in Example 2 3-X Oxygen reduction linear polarization curves of / ZIF-C and commercial Pt / C catalysts in alkaline media after removing the nitrogen background.

[0035] Figure 9 TiO2 prepared in Example 3 2-X Oxygen reduction linear polarization curves of / MOF-C and commercial Pt / C catalysts in alkaline media after removing the nitrogen background. Detailed Implementation

[0036] The following description, in conjunction with specific embodiments, provides a complete and clearer explanation of this technical solution. Unless otherwise specified, all technical means employed are existing technologies. Unless otherwise specified, the materials and reagents used in the embodiments of this invention are commercially available.

[0037] Example 1: ZrO 2-x / MOF-C catalyst (1) Preparation of MOF-C used as carbon support 10 mmol of terephthalic acid was weighed and dissolved in 100 mL of N,N-dimethylformamide. After complete dissolution, 20 mmol of zinc nitrate hexahydrate was added, and stirring was continued until dissolved. Then, 5 mL of triethanolamine was added, and the mixture was stirred for 12–24 h. After the reaction was completed, MOF-5 samples were obtained by centrifugation. The samples were dried in an oven and then calcined in a tube furnace under an argon atmosphere at 900–1000 °C for 1–2 h to finally obtain the derived carbon of MOF-5 (MOF-C).

[0038] (2) ZrO 2-x Preparation of MOF-C precursor Weigh out 0.2–2 mmol of zirconium acetylacetonate and dissolve it in 50 mL of anhydrous ethanol to prepare a precursor solution. Then, add the precursor solution to 0.2–1 g of MOF-C support, stir for 1–2 h, and then treat with ultrasound and heating to obtain ZrO. 2-x / MOF-C precursor.

[0039] (3) ZrO 2-x Preparation of / MOF-C catalyst Weigh out 0.1~0.5 g of ZrO. 2-x The MOF-C precursor was placed in a quartz boat, which was then placed in a tube furnace equipped with a quartz tube. Argon gas was first introduced for 30-60 minutes to purge the air from the quartz tube. The tube furnace was then heated from room temperature to 700-1000℃ at a rate of 1-5℃ / min. After reaching the target temperature, it was kept at a constant temperature for 1 hour and finally cooled naturally to room temperature to obtain the desired catalyst sample.

[0040] (4) Structural morphology and elemental characterization of the catalyst ZrO2 can be seen from field emission transmission electron microscopy (TEM). 2-x Morphology of MOF-C catalyst ( Figure 1 ), and the lattice fringes of nano-zirconia can be clearly seen using a high-resolution transmission electron microscope. Figure 2 This confirmed that it was ZrO. 2-x Nano-zirconia structure in MOF-C catalyst.

[0041] ZrO was characterized by X-ray diffraction. 2-x Phase structure information of MOF-C catalysts ( Figure 3 ).from Figure 3 It can be seen that the prepared ZrO 2-x The diffraction peaks of the / MOF-C material differ from those of the standard ZrO2 card, which further confirms that ZrO 2-x The zirconia nanoparticles of the / MOF-C catalyst exist with extremely small particle sizes.

[0042] ZrO2 was compared using synchrotron extended X-ray fine structure absorption spectroscopy (EXFAS). 2-x Coordination environment of / MOF-C and commercial ZrO2 ( Figure 4 ).from Figure 4 It can be seen that the prepared ZrO 2-x The coordination environment of / MOF-C materials is significantly different from that of commercial ZrO2. The fitting analysis results in Table 1 show that ZrO2... 2-x The Zr-O coordination number in the / MOF-C material is 4.72, significantly lower than the Zr-O coordination number (5.78) of commercial ZrO2, confirming that ZrO2... 2-x The nano-zirconia in the / MOF-C material exists in a low-oxygen coordination form.

[0043] (5) ORR performance test of catalyst A three-electrode system was used to perform linear voltammetric scans in oxygen- and nitrogen-saturated 0.1 M KOH at a scan rate of 10 mV / s and an electrode rotation speed of 1600 rpm. The voltammetric curves in oxygen-saturated 0.1 M KOH were then subtracted from the voltammetric curves in nitrogen-saturated 0.1 M KOH. Figure 5 ).

[0044] Unless otherwise specified, the ORR performance testing methods for the catalysts involved in this invention in alkaline media are the same as those described above.

[0045] The catalyst prepared in this embodiment exhibits excellent ORR performance in alkaline media, with an ORR onset potential of 0.94 V vs. RHE and an ORR half-wave potential of 0.85 V vs. RHE. After a constant voltage discharge test at 0.7 V vs. RHE for 40,000 s, the electrochemical activity retention rate is 89%, which is superior to that of commercial 20% Pt / C catalysts. Figure 6 Meanwhile, the ORR half-wave potential only showed a 2 mV decay ( Figure 7 ).

[0046] Table 1

[0047] In the table: CN: oxygen coordination number; σ 2 Mean square disorder; E 0： Reference energy offset R: bond length; R-factor: fit quality.

[0048] Example 2: CrO 3-x / ZIF-C catalyst (1) Preparation of ZIF-C used as a carbon support 10 mmol of zinc nitrate hexahydrate was weighed and dissolved in 170 mL of methanol to prepare solution A; 40 mmol of 2-methylimidazole was dissolved in 30 mL of methanol to prepare solution B. After both solutions were completely dissolved, solutions A and B were mixed and stirred for 12–24 h. After the reaction was completed, the product was washed with methanol and centrifuged to obtain ZIF-8 sample. The sample was dried in an oven and then placed in a tube furnace under an argon atmosphere and calcined at 900–1000 °C for 1–2 h to obtain the derived carbon of ZIF-8 (ZIF-C).

[0049] (2) CrO 3-x Preparation of ZIF-C precursor 0.2–2 mmol of chromium acetylacetone was dissolved in 50 mL of anhydrous ethanol to prepare a precursor solution. Then, 0.2–1 g of ZIF-C was added to the precursor solution, and the mixture was stirred for 1–2 h. After sonication and heating with stirring, CrO was obtained. 3-x / ZIF-C precursor.

[0050] (3) CrO 3-x Preparation of ZIF-C catalyst Weigh out 0.1~0.5 g of CrO 3-x The ZIF-C precursor was placed in a quartz boat, which was then placed in a tube furnace equipped with a quartz tube. Argon gas was first introduced for 30-60 minutes to purge the air from the quartz tube. The tube furnace was then heated from room temperature to 700-1000℃ at a heating rate of 1-5℃ / min. After reaching the target temperature, it was kept at a constant temperature for 1 hour and finally cooled naturally to room temperature to obtain the desired catalyst sample.

[0051] (4) ORR performance test of catalyst A three-electrode system was used to perform linear voltammetric scans in oxygen- and nitrogen-saturated 0.1 M KOH at a scan rate of 10 mV / s and an electrode rotation speed of 1600 rpm. The voltammetric curves in oxygen-saturated 0.1 M KOH were then subtracted from the voltammetric curves in nitrogen-saturated 0.1 M KOH. Figure 8 ).

[0052] The catalyst prepared in this embodiment has an ORR onset potential of 0.925 V vs. RHE in alkaline medium and an ORR half-wave potential of 0.835 V vs. RHE.

[0053] Example 3: TiO 2-x / MOF-C catalyst (1) Preparation of MOF-C used as carbon support 10 mmol of terephthalic acid was weighed and dissolved in 100 mL of N,N-dimethylformamide. After complete dissolution, 20 mmol of zinc nitrate hexahydrate was added, and the mixture was stirred until dissolved. Then, 5 mL of triethanolamine was added, and the mixture was stirred for 12–24 h. After the reaction was completed, the MOF-5 sample was obtained by centrifugation. The sample was dried in an oven and then calcined in a tube furnace under an argon atmosphere at 900–1000 °C for 1–2 h to finally obtain the derived carbon of MOF-5 (MOF-C).

[0054] (2) TiO 2-x Preparation of MOF-C precursor Weigh out 0.2–2 mmol of titanium acetylacetone and dissolve it in 50 mL of anhydrous ethanol to prepare a precursor solution. Then, add the precursor solution to 0.2–1 g of MOF-C support, stir for 1–2 h, and then treat with ultrasound and heating to obtain TiO2. 2-x / MOF-C precursor.

[0055] (3) TiO 2-x Preparation of / MOF-C catalyst Weigh out 0.1~0.5 g of TiO2. 2-x The MOF-C precursor was placed in a quartz boat, which was then placed in a tube furnace equipped with a quartz tube. Argon gas was first introduced for 30-60 minutes to purge the air from the quartz tube. The tube furnace was then heated from room temperature to 700-1000℃ at a rate of 1-5℃ / min. After reaching the target temperature, it was kept at a constant temperature for 1 hour and finally cooled naturally to room temperature to obtain the desired catalyst sample.

[0056] (4) ORR performance test of catalyst A three-electrode system was used to perform linear voltammetric scans in oxygen- and nitrogen-saturated 0.1 M KOH at a scan rate of 10 mV / s and an electrode rotation speed of 1600 rpm. The voltammetric curves in oxygen-saturated 0.1 M KOH were then subtracted from the voltammetric curves in nitrogen-saturated 0.1 M KOH. Figure 9 ).

[0057] The catalyst prepared in this embodiment has an ORR onset potential of 0.915 V vs. RHE in alkaline medium and an ORR half-wave potential of 0.825 V vs. RHE.

[0058] It should be noted that the acetylacetone salts used in this invention include any one of the following: scandium acetylacetone, yttrium acetylacetone, zirconium acetylacetone, titanium acetylacetone, hafnium acetylacetone, vanadium acetylacetone, niobium acetylacetone, tantalum acetylacetone, chromium acetylacetone, molybdenum acetylacetone, and tungsten acetylacetone. They can also be used in combination. When mixing, they can be in any mass ratio, such as 1:1, 1:2, etc. The concentration of the acetylacetone salt in the metal salt solution can be in the range of 0.01-1 mol / L. The porous carbon support can be any one or more of ZIF, MOF, COF and their derivative supports. When the two supports are mixed, they can be in any ratio, such as 1:1, 1:2. Since the performance of the obtained catalysts is within the data range provided in Examples 1-3 of this invention, they will not be described redundantly in order to reduce unnecessary repetition.

[0059] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-described technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing porous carbon-supported low-oxygen coordinated nano-oxide catalysts, characterized in that, The process involves dissolving acetylacetone salt in deionized water or anhydrous ethanol to prepare a metal salt solution, then adding the metal salt solution to a porous carbon support and mixing it. After heating and stirring, a precursor is obtained. Subsequently, the precursor is placed in a tube furnace and calcined in an inert gas atmosphere to finally obtain a porous carbon-supported low-oxygen coordination nano-oxide alkaline fuel cell catalyst.

2. The method according to claim 1, characterized in that, The acetylacetone salts include any one or more of the following: scandium acetylacetone, yttrium acetylacetone, zirconium acetylacetone, titanium acetylacetone, hafnium acetylacetone, vanadium acetylacetone, niobium acetylacetone, tantalum acetylacetone, chromium acetylacetone, molybdenum acetylacetone, and tungsten acetylacetone.

3. The method according to claim 1, characterized in that, The acetylacetone salt is dissolved in water or ethanol, wherein the concentration of the acetylacetone salt in the metal salt solution is 0.01-1 mol / L.

4. The method according to claim 1, characterized in that, The porous carbon support includes any one or more of ZIF, MOF, COF and their derivative supports.

5. The method according to claim 1, characterized in that, The metal salt solution was added to the porous carbon support and mixed by stirring or sonication for 0.5-3 hours.

6. The method according to claim 5, characterized in that, The precursor obtained by heating and stirring is produced by using a magnetic heating stirrer, water bath, oil bath or sand bath to evaporate the solvent. The heating temperature is 70-120℃ and the heating time is 3-6h.

7. The method according to claim 1, characterized in that, The precursor is placed in a tube furnace, and the calcination atmosphere is argon or nitrogen. The calcination temperature is 700-1100℃, and the calcination time is 0.5-5 h.

8. The method according to claim 1, characterized in that, The nano-oxides include any one or more of nano-scandium oxide, nano-yttrium oxide, nano-titanium oxide, nano-zirconium oxide, nano-hafnium oxide, nano-vanadium oxide, nano-niobium oxide, nano-tantalum oxide, nano-molybdenum oxide, and nano-tungsten oxide.

9. A porous carbon-supported low-oxygen coordination nano-oxide catalyst, characterized in that, The catalyst is prepared by any one of the methods described in claims 1-8, wherein the particle size of the low-oxygen coordination nano-oxide is 1-20 nm.

10. The application of the catalyst according to claim 9, wherein the catalyst is used as a cathode catalyst in an alkaline fuel cell and participates in the oxygen reduction reaction in an alkaline electrolyte.

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