Polymer oxygen reduction catalyst and method of making the same

Abstract

This invention relates to the field of electrochemical oxygen reduction reaction catalyst technology, specifically to a polymer oxygen reduction catalyst and its preparation method. The catalyst has structural units comprising the structure shown in formula (I); in formula (I), M is selected from at least one of Fe, Ni, and Cu; R is a C1-C6 alkylene group; X is a halogen; Z1, Z2, Z3, and Z4 are each independently selected from one of N, O, and S; Y is H or -R-N. + (CH3)3 X ˉ Where R is a C1-C6 alkylene group, X is a halogen, and * indicates a connecting end; where Z1, Z2, Z3, and Z4 are each independently N, Y is -R-N. + (CH3)3 X ˉ When Z1, Z2, Z3, and Z4 are each independently O or S, Y is H. The polymer oxygen reduction catalyst in this invention achieves efficient electron-ion synergistic transport and possesses both excellent structural stability and catalytic performance.

Description

Technical Field

[0001] This invention relates to the field of electrochemical oxygen reduction reaction catalyst technology, specifically to a polymer oxygen reduction catalyst and its preparation method. Background Technology

[0002] The oxygen reduction reaction (ORR) is the core cathode reaction in novel energy storage devices such as fuel cells and flow batteries. Its reaction kinetics and catalytic efficiency directly determine the energy conversion efficiency and performance of the device. Therefore, developing high-performance ORR catalysts is one of the key tasks for promoting the industrial application of such energy storage devices. However, currently, commercial membrane electrode assemblies (MEAs) widely use direct catalyst coating technology, directly mixing noble metal catalysts and other mass transfer functional materials into a slurry for coating. This results in insufficient exposure of catalytic sites in the catalyst layer and poor integrity and efficiency of the multiphase component mass transfer pathways. In particular, it causes poor conductivity of electrons and ions that need to be transferred simultaneously in space and air, leading to low oxygen mass transfer efficiency.

[0003] Among numerous novel catalyst support materials, covalent organic frameworks (COFs) have become a research hotspot in the field of ORR catalysts due to their long-range ordered porous structure, high specific surface area, tunable chemical composition, and excellent structural stability. However, existing COFs-based ORR catalysts still have many shortcomings: most COFs materials themselves suffer from poor intrinsic conductivity and lack ordered ion conduction pathways, making it difficult to achieve efficient and coordinated electron and ion transport; at the same time, some COFs materials have relatively poor chemical stability and are prone to hydrolysis or structural damage in the acid-base electrolyte environment of ORR reactions. In addition, existing functionalization modification strategies for COFs are difficult to achieve synergistic improvement in both electronic and ion conduction performance, often focusing only on one aspect, failing to fundamentally solve the core problems of fragmented electron-ion conduction and low mass transfer efficiency in traditional catalysts, thus restricting further breakthroughs in the performance of COFs-based ORR catalysts.

[0004] Currently, there are few reports on single-phase oxygen reduction catalysts possessing both efficient electronic and ionic conductivity in both space and space; existing reports mostly focus on optimizing the transport of a single conductivity type. In 2025, a research team led by Xiang Zhonghua from Beijing University of Chemical Technology reported thiazolium-linked hybrid electron-ion conductive COFs (MEICOFs) with a hydroxide ion conductivity of only 0.01 S•m. -1 The ion conduction capacity is significantly different from the actual operating conditions required for catalytic oxygen reduction. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems of traditional ORR catalysts having single intrinsic electron or ion conduction capabilities and poor performance, insufficient exposure of catalytic sites, and low mass transfer efficiency of reactants due to the use of disordered electron / ion additives. This invention provides a polymer oxygen reduction catalyst and its preparation method. This polymer oxygen reduction catalyst can achieve efficient electron-ion synergistic transport, and has both excellent structural stability and catalytic performance. It combines the structural advantages and functional tunability of COFs materials to construct an oxygen reduction catalyst with ordered electron-ion simultaneous spatial and temporal conduction channels.

[0006] To achieve the above objectives, a first aspect of the present invention provides a polymer oxygen reduction catalyst having structural units comprising the structure shown in formula (I): Formula (I); In formula (I), M is selected from at least one of Fe, Ni, and Cu; R is a C1-C6 alkylene group; X is a halogen; Z1, Z2, Z3, and Z4 are each independently selected from one of N, O, and S; Y is H or -RN. + (CH3)3X ˉ , where R is a C1-C6 alkylene group, X is a halogen, and * indicates a connecting end; When Z1, Z2, Z3, and Z4 are each independently N, Y is -RN. + (CH3)3X ˉ When Z1, Z2, Z3, and Z4 are each independently O or S, Y is H.

[0007] A second aspect of the present invention provides a method for preparing a polymer oxygen reduction catalyst, the method comprising: S1. Nitrogen-containing organic ligands, perfluorinated metal phthalocyanines and solvents are mixed, and then an alkaline catalyst is added to carry out a freeze-vacuum-thaw cycle. The reaction is carried out under sealed conditions, and after purification and drying, the metal phthalocyanine covalent organic material is obtained. S2. In the presence of an inert gas, a covalent organic metal phthalocyanine, a quaternary ammonium salt, and an organic solvent are brought into contact for an alkylation reaction. The nitrogen-containing organic ligand is selected from at least one of 1,2,4,5-phenyltetramine tetrahydrochloride, 2,5-diamino-1,4-phenyldithiophene dihydrochloride and 2,5-diamino-1,4-dihydroxyphenyl dihydrochloride; The perfluorinated metal phthalocyanine is selected from at least one of perfluorinated iron phthalocyanine, perfluorinated copper phthalocyanine, and perfluorinated nickel phthalocyanine; The general structural formula of the quaternary ammonium salt is XRN. + (CH3)3X ˉ R is a C1-C6 alkylene group, and X is a halogen.

[0008] A third aspect of the present invention provides a polymer oxygen reduction catalyst prepared by the method described herein.

[0009] The invention, through the above technical solution, has at least the following beneficial effects: 1. The catalyst in this invention has excellent dual electron and ion transport capabilities. Based on the structural advantages and functional tunability of COFs materials, quaternary ammonium salt groups are anchored in the COFs channels to construct an ordered ion-conducting pathway, which significantly improves the ion transport efficiency of the catalyst. 2. By modifying quaternary ammonium salt groups, this invention can avoid the destruction of the framework structure and ensure the crystallinity and structural stability of the catalyst. Attached Figure Description

[0010] Figure 1 These are the X-ray diffraction (XRD) spectra of the polymer oxygen reduction catalyst in Example 1 and the metal phthalocyanine covalent organic material in Comparative Example 1; Figure 2 These are the X-ray diffraction (XRD) spectra of the polymer oxygen reduction catalyst in Example 2 and the metal phthalocyanine covalent organic material in Comparative Example 2; Figure 3 These are the X-ray diffraction (XRD) spectra of the polymer oxygen reduction catalyst in Example 3 and the metal phthalocyanine covalent organic material in Comparative Example 3; Figure 4 These are the infrared spectra of 1,2,4,5-phenyltetramine tetrahydrochloride (BTM), perfluoroferrophthalocyanine, and the polymer oxygen reduction catalyst in Example 1. Figure 5 The infrared spectra of the metal phthalocyanine covalent organic material (FePc-COF) in Comparative Example 1 and the polymer oxygen reduction catalyst (FePc-COF-lian) and quaternary ammonium salt (3-bromopropyltrimethylammonium bromide) in Example 1 are shown below. Figure 6 The nitrogen adsorption-desorption curves are shown for the metal phthalocyanine covalent organic material (NiPc-COF) in Comparative Example 3 and the polymer oxygen reduction catalyst (NiPc-COF-lian) in Example 3. Figure 7 The Nyquist plots are for the metal phthalocyanine covalent organic materials (MPc-COF) in Comparative Examples 1-3 and the polymer oxygen reduction catalyst (MPc-COF-lian) in Examples 1-3. Figure 8 These are linear sweep voltammetry (LSV) curves of the polymer oxygen reduction catalyst in Examples 1 and 4-6, and the metal phthalocyanine covalent organic material in Comparative Example 1. Figure 9XPS spectra of the metal phthalocyanine covalent organic material (FePc-COF) in Comparative Example 1 and the polymer oxygen reduction catalyst (FePc-COF-lian) in Example 1; Figure 10 The experimental and simulation data are the crystal structure (XRD pattern) of the metal phthalocyanine covalent organic material (FePc-COF) in Comparative Example 1. Figure 11 The experimental and simulation data are the crystal structure (XRD pattern) of the metal phthalocyanine covalent organic material (CuPc-COF) in Comparative Example 2. Figure 12 The experimental and simulation data are the crystal structure (XRD pattern) of the metal phthalocyanine covalent organic material (NiPc-COF) in Comparative Example 3. Detailed Implementation

[0011] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0012] This invention provides a polymer oxygen reduction catalyst having structural units as shown in formula (I): Formula (I); In formula (I), M is selected from at least one of Fe, Ni, and Cu; R is a C1-C6 alkylene group; X is a halogen; Z1, Z2, Z3, and Z4 are each independently selected from one of N, O, and S; Y is H or -RN. + (CH3)3X ˉ , where R is a C1-C6 alkylene group, X is a halogen, and * indicates a connecting end; When Z1, Z2, Z3, and Z4 are each independently N, Y is -RN. + (CH3)3X ˉ When Z1, Z2, Z3, and Z4 are each independently O or S, Y is H.

[0013] The catalyst in this invention has excellent dual electron and ion transport capabilities. Combining the structural advantages and functional tunability of COFs materials, the COFs materials are modified with quaternary ammonium salt groups, which anchor the quaternary ammonium salt groups in the COFs channels, thereby constructing an ordered ion-conducting pathway, which can significantly improve the ion transport efficiency of the catalyst. In addition, the catalyst also has good crystallinity and structural stability.

[0014] According to the present invention, there are no special restrictions on the selection of C1-C6 alkylene groups as long as the purpose of the present invention can be achieved. They can be straight-chain alkylene groups or branched alkylene groups, such as methylene, ethylene, propylene, isopropylene, butylene, 1-methyl-1,3-propylene, 2-methyl-1,3-propylene, pentylene, 1-methyl-1,4-butylene, hexylene, 1-methyl-1,5-pentylene, etc.

[0015] According to a preferred embodiment of the present invention, M is Fe and / or Ni, preferably Fe. This can further improve the ion transport efficiency, ion conductivity, and crystallinity of the catalyst.

[0016] According to a preferred embodiment of the present invention, R is a C2-C4 alkylene group, preferably at least one of ethylene, propylene, and butylene, and more preferably propylene. The aforementioned embodiments can further improve the electron transport and ion transport capabilities of the catalyst, resulting in a high electrochemical onset potential and half-wave potential, exhibiting activity superior to most CODs-based catalysts.

[0017] According to the present invention, there are no special restrictions on the selection of X in the quaternary ammonium salt group, as long as it is conducive to the anchoring of the quaternary ammonium salt group within the COFs pores. In a preferred embodiment of the present invention, X is Cl and / or Br, preferably Br. The aforementioned embodiments can improve the electronic conductivity and chloride ion conductivity of the catalyst, and simultaneously possess high electrochemical onset potential and half-wave potential, exhibiting activity superior to most CODs-based catalysts.

[0018] In this invention, Z1, Z2, Z3, and Z4 are derived from nitrogen-containing organic ligands. The quaternary ammonium salt will only undergo alkylation when an N atom is present in the nitrogen-containing organic ligand. According to a preferred embodiment of the invention, Z1, Z2, Z3, and Z4 are each independently N. The aforementioned embodiments can increase the grafting rate of the quaternary ammonium salt groups, which is beneficial for improving the ion transport efficiency of the catalyst.

[0019] The catalyst in this invention possesses excellent dual electron and ion transport capabilities. According to one embodiment of the invention, the onset potential of the polymer oxygen reduction catalyst is 0.8-1V, for example, 0.81V, 0.82V, 0.83V, 0.84V, 0.85V, 0.86V, 0.87V, 0.88V, 0.89V, 0.9V, 0.91V, 0.92V, 0.93V, 0.94V, 0.95V, 0.96V, 0.97V, 0.98V, or 0.99V, or any range of two of the above values.

[0020] The catalyst in this invention possesses excellent dual electron and ion transport capabilities. According to one embodiment of the invention, the half-wave potential of the polymer oxygen reduction catalyst is 0.6-0.9V, for example, 0.61V, 0.63V, 0.64V, 0.65V, 0.66V, 0.67V, 0.68V, 0.7V, 0.72V, 0.73V, 0.75V, 0.78V, 0.79V, 0.8V, 0.81V, 0.82V, 0.83V, 0.84V, 0.85V, 0.86V, 0.87V, 0.88V, or 0.89V, or any range of two of the above values.

[0021] The catalyst in this invention exhibits excellent electronic conductivity. According to one embodiment of the invention, the electronic conductivity of the polymer oxygen reduction catalyst is 0.8-1.8 S•m. -1 For example, 0.82 S•m -1 0.84 S•m -1 0.87 S•m -1 0.9 S•m -1 0.92 S•m -1 0.95 S•m -1 1 S•m -1 1.1 S•m -1 1.2 S•m -1 1.3 S•m -1 1.4 S•m -1 1.5 S•m -1 1.6 S•m -1 Or 1.7 S•m -1 , and the range formed by any two of the above values.

[0022] The catalyst in this invention exhibits excellent chloride ion conductivity. According to one embodiment of the invention, under conditions of 80°C and 100% humidity, the chloride ion conductivity of the polymer oxygen reduction catalyst is 98-130 mS•cm. -1 For example, 98.5 mS•cm -1 98.9 mS•cm -1 99mS•cm -1 99.5 mS•cm -1 100mS•cm -1 102mS•cm -1 105mS•cm -1 108mS•cm -1 110mS•cm -1 113mS•cm -1 115mS•cm -1120mS•cm -1 125mS•cm -1 126.8 mS•cm -1 Or 128 mS•cm -1 , and the range formed by any two of the above values.

[0023] This invention provides a method for preparing a polymer oxygen reduction catalyst, the method comprising: S1. Nitrogen-containing organic ligands, perfluorinated metal phthalocyanines and solvents are mixed, and then an alkaline catalyst is added to carry out a freeze-vacuum-thaw cycle. The reaction is carried out under sealed conditions, and after purification and drying, the metal phthalocyanine covalent organic material is obtained. S2. In the presence of an inert gas, a covalent organic metal phthalocyanine, a quaternary ammonium salt, and an organic solvent are brought into contact for an alkylation reaction. The nitrogen-containing organic ligand is selected from at least one of 1,2,4,5-phenyltetramine tetrahydrochloride, 2,5-diamino-1,4-phenyldithiophene dihydrochloride and 2,5-diamino-1,4-dihydroxyphenyl dihydrochloride; The perfluorinated metal phthalocyanine is selected from at least one of perfluorinated iron phthalocyanine, perfluorinated copper phthalocyanine, and perfluorinated nickel phthalocyanine; The general structural formula of the quaternary ammonium salt is XRN. + (CH3)3X ˉ R is a C1-C6 alkylene group, and X is a halogen.

[0024] According to the present invention, by combining the structural advantages and functional tunability of COFs materials, an oxygen reduction catalyst with an ordered electron-ion co-space conduction channel can be constructed by post-modifying quaternary ammonium salt groups, thereby achieving efficient electron-ion synergistic transport. At the same time, the catalyst also has excellent structural stability and catalytic performance.

[0025] According to the present invention, there are no special restrictions on the selection of C1-C6 alkylene groups as long as the purpose of the present invention can be achieved. They can be straight-chain alkylene groups or branched alkylene groups, such as methylene, ethylene, propylene, isopropylene, butylene, 1-methyl-1,3-propylene, 2-methyl-1,3-propylene, pentylene, 1-methyl-1,4-butylene, hexylene, 1-methyl-1,5-pentylene, etc.

[0026] The quaternary ammonium salt will only undergo alkylation when a nitrogen atom is present in the nitrogen-containing organic ligand. According to a preferred embodiment of the present invention, the nitrogen-containing organic ligand is 1,2,4,5-phenyltetramine tetrahydrochloride. The aforementioned embodiments can increase the grafting rate of the quaternary ammonium salt group, which is beneficial for improving the ion transport efficiency of the catalyst.

[0027] According to a preferred embodiment of the present invention, the perfluorinated metal phthalocyanine is perfluorophthalocyanine iron and / or perfluorophthalocyanine nickel, preferably perfluorophthalocyanine iron. The foregoing embodiments can further improve the ion transport efficiency, ion conductivity, and crystallinity of the prepared catalyst.

[0028] According to the present invention, the solvent can be any type in the art. In a preferred embodiment, the solvent is an organic solvent, preferably selected from at least two of mesitylene, N,N-dimethylacetamide, 1,4-dioxane, toluene, N,N-dimethylformamide, o-dichlorobenzene, and n-butanol, more preferably mesitylene and N,N-dimethylacetamide, with a volume ratio of 1-5:1, for example, 1:1, 2:1, 3:1, 4:1, or 5:1. The foregoing embodiments can further improve the ion transport efficiency, ion conductivity, and crystallinity of the prepared catalyst.

[0029] In this invention, the type of alkaline catalyst can be a conventional choice in the art. According to one embodiment of the invention, the alkaline catalyst is selected from at least one of triethylamine, ammonia, and trimethylamine; preferably triethylamine. The foregoing embodiments can further improve the ion transport efficiency, ion conductivity, and crystallinity of the prepared catalyst.

[0030] According to the present invention, the molar ratio of nitrogen-containing organic ligand to perfluorinated metal phthalocyanine can be selected within a wide range, as long as the objective of the present invention can be achieved. According to one embodiment of the present invention, the molar ratio of nitrogen-containing organic ligand to perfluorinated metal phthalocyanine is 1-3:1. The present invention uses a molar ratio of 2:1 as an example to illustrate the advantages of the present invention, and does not represent a limitation thereof.

[0031] According to the present invention, the range of the molar ratio of the solvent to the perfluorinated metal phthalocyanine is relatively wide, as long as the objective of the present invention can be achieved. According to one embodiment of the present invention, the molar ratio of the solvent to the perfluorinated metal phthalocyanine is 0.1-1:1, for example, 0.2:1, 0.3:1, 0.4:1, 0.5:1, 0.6:1, 0.7:1, 0.8:1, or 0.9:1.

[0032] This invention does not impose any particular limitation on the molar ratio of the alkali catalyst to the perfluorinated metal phthalocyanine. According to one embodiment of the invention, the molar ratio of the alkali catalyst to the perfluorinated metal phthalocyanine is 0.05-0.2:1. The invention uses a molar ratio of 0.1:1 for the alkali catalyst to the perfluorinated metal phthalocyanine as an example to illustrate the advantages of the invention, and does not represent a limitation thereof.

[0033] According to one embodiment of the present invention, the mixing of the nitrogen-containing organic ligand, the perfluorinated metal phthalocyanine, and the solvent is carried out under sealed conditions and with ultrasonic assistance. Preferably, the ultrasonic power is 100-150W and the duration is 5-15 minutes. This invention uses ultrasonication at 120W for 5 minutes as an example to illustrate the advantages of the invention, but this does not constitute a limitation of the invention. The sealed conditions in this invention mainly refer to sealing the opening of the reaction vessel containing the nitrogen-containing organic ligand, the perfluorinated metal phthalocyanine, and the solvent with a sealing film to prevent contamination and to prevent water from entering the vessel during ultrasonication.

[0034] Freezing-vacuum-thawing cycles are a well-known and conventional technique for preparing covalent organic framework materials. The following illustrative description of the conditions is not intended to limit the invention. According to one embodiment of the invention, the freezing-vacuum-thawing cycle method includes: freezing with liquid nitrogen, the freezing time being adjusted according to actual conditions, until the liquid in the reaction vessel is completely solidified; then evacuating the reaction vessel to a vacuum, for example, a vacuum degree of 1 × 10⁻⁶. -5 Maintain Pa for 10 minutes; then thaw in a water bath at room temperature until the solid in the reaction vessel has completely turned into a liquid; repeat this process 3-5 times. During the final vacuuming, a vacuum should be created while the bottle mouth is sealed with a flame to create an oxygen-free environment and prevent oxidation and deterioration of the substances.

[0035] The contact reaction between nitrogen-containing organic ligands and perfluorinated metal phthalocyanines in this invention is a well-known nucleophilic substitution reaction in the art, and its specific conditions are not particularly required. The following is an illustrative description, but it does not limit the scope of the invention. According to one embodiment of the invention, the contact reaction conditions include: a temperature of 100-140°C and a time of 3-6 days. This invention uses a reaction at 120°C for 5 days as an example to illustrate the advantages of the invention, and does not represent a limitation thereof. The contact reaction temperature can be preheated to the target temperature, or it can start at room temperature at 1-5 K·min. -1 The heating rate is such that the target temperature is reached, but there are no special requirements for this invention.

[0036] Purification and drying are conventional techniques in this invention and will not be described in detail here.

[0037] According to a specific embodiment of the present invention, a nitrogen-containing organic ligand, a perfluorinated metal phthalocyanine, and a solvent are added to a glass ampoule, which is then sealed with a paraffin film. The ampoule is then sonicated at 120W for 5 minutes to obtain a homogeneous slurry. An alkaline catalyst is added to the slurry and immediately placed in liquid nitrogen for freezing. The glass ampoule is then evacuated to a vacuum level of 1×10⁻⁶. -5The solution was frozen at 10°C for 10 minutes, then thawed in a water bath at 25°C. This freeze-vacuum-thaw cycle was repeated three times. During the final vacuuming, the ampoule mouth was typically sealed with a flame, and the glass ampoule was then allowed to cool to room temperature. A contact reaction was then carried out. After the reaction, the reaction solution was cooled to room temperature, and the solid was separated. The solid was washed with a mixture of tetrahydrofuran (THF) and methanol at a volume ratio of 5-10:1, and centrifuged until the supernatant was nearly colorless. The metal phthalocyanine covalent organic material, denoted as MPc-COF, was obtained by vacuum drying with supercritical carbon dioxide in a Tousimis Samdri PVT-3D critical point desiccator.

[0038] In this invention, the presence of an inert gas means that the environment is filled with an inert gas. As long as the purpose of this invention can be achieved, there are no special restrictions on the choice of inert gas, such as nitrogen or argon.

[0039] According to a preferred embodiment of the present invention, R in the quaternary ammonium salt structure is a C2-C4 alkylene group, preferably at least one of ethylene, propyleneene, and butylene, and more preferably propyleneene. The foregoing embodiments can further improve the electron transport and ion transport capabilities of the prepared catalyst.

[0040] According to a preferred embodiment of the present invention, X in the quaternary ammonium salt structural formula is Cl and / or Br, preferably Br. This can improve the electronic conductivity and chloride ion conductivity of the prepared catalyst, and simultaneously possesses high electrochemical onset potential and half-wave potential, exhibiting activity superior to most CODs-based catalysts.

[0041] According to a more preferred embodiment of the present invention, the quaternary ammonium salt is selected from at least one of (2-bromoethyl)-trimethylammonium bromide, (3-bromopropyl)-trimethylammonium bromide, and (4-bromobutyl)-trimethylammonium bromide, preferably (3-bromopropyl)-trimethylammonium bromide. The foregoing embodiments can improve the dual electron and ion transport capability of the prepared catalyst.

[0042] There are no particular restrictions on the specific choice of organic solvent, as long as it is conducive to the alkylation reaction. According to one embodiment of the present invention, the organic solvent is selected from dichloromethane and / or N,N-dimethylformamide, preferably dichloromethane.

[0043] In this invention, to facilitate the alkylation reaction, the organic solvent needs to meet the conditions of being oxygen-free and anhydrous. According to one embodiment of the invention, the organic solvent is oxygen-free and has a water content of <20 wppm. Reducing the water and oxygen content in the organic solvent can be done using conventional techniques in the art, and this invention does not have any special requirements in this regard.

[0044] According to one embodiment of the present invention, the mass ratio of the metal phthalocyanine covalent organic material to the quaternary ammonium salt is 1:5-20, for example, 1:6, 1:7, 1:8, 1:9, 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:18, or 1:19, or any range of two of the above values. The present invention uses a mass ratio of 1:13.2 of metal phthalocyanine covalent organic material to quaternary ammonium salt as an example to illustrate the advantages of the present invention, and does not represent a limitation thereof. The foregoing embodiments are beneficial for improving the ion transport efficiency of the catalyst.

[0045] There are no special requirements for the mass ratio of metal phthalocyanine covalent organic material to organic solvent, as long as it is conducive to the occurrence of alkylation reaction.

[0046] According to one embodiment of the present invention, the alkylation reaction conditions include a temperature of 25-60°C and a time of 1-3 days. The present invention uses a reaction at 40°C for 48 hours as an example to illustrate the advantages of the invention, but this does not represent a limitation thereof. After the alkylation reaction is completed, the polymer oxygen reduction catalyst is obtained by purification and drying according to conventional methods in the art. For example, the reaction solution is subjected to multiple centrifugation and washing (the washing liquid is tetrahydrofuran to water in a volume ratio of 1:1-3), followed by vacuum drying at 110°C for 6 hours.

[0047] This invention provides a polymer oxygen reduction catalyst prepared by the method described herein. In this invention, the catalyst is modified with quaternary ammonium salt groups to anchor these groups within the COF pores, thereby constructing an ordered ion-conducting pathway and significantly improving the catalyst's ion transport efficiency. Furthermore, the catalyst exhibits good crystallinity and structural stability.

[0048] The catalyst prepared by this invention exhibits excellent dual electron and ion transport capabilities. According to one embodiment of the invention, the onset potential of the polymer oxygen reduction catalyst is 0.8-1V, for example, 0.81V, 0.82V, 0.83V, 0.84V, 0.85V, 0.86V, 0.87V, 0.88V, 0.89V, 0.9V, 0.91V, 0.92V, 0.93V, 0.94V, 0.95V, 0.96V, 0.97V, 0.98V, or 0.99V, or any range of two of the above values.

[0049] The catalyst prepared by this invention exhibits excellent dual electron and ion transport capabilities. According to one embodiment of the invention, the half-wave potential of the polymer oxygen reduction catalyst is 0.6-0.9V, for example, 0.61V, 0.63V, 0.64V, 0.65V, 0.66V, 0.67V, 0.68V, 0.7V, 0.72V, 0.73V, 0.75V, 0.78V, 0.79V, 0.8V, 0.81V, 0.82V, 0.83V, 0.84V, 0.85V, 0.86V, 0.87V, 0.88V, or 0.89V, or any range of two of the above values.

[0050] The catalyst prepared by this invention exhibits excellent electronic conductivity. According to one embodiment of the invention, the electronic conductivity of the polymer oxygen reduction catalyst is 0.8-1.8 S•m. -1 For example, 0.82 S•m -1 0.84 S•m -1 0.87 S•m -1 0.9 S•m -1 0.92 S•m -1 0.95 S•m -1 1 S•m -1 1.1 S•m -1 1.2 S•m -1 1.3 S•m -1 1.4 S•m -1 1.5 S•m -1 1.6 S•m -1 Or 1.7 S•m -1 , and the range formed by any two of the above values.

[0051] The catalyst prepared by this invention exhibits excellent chloride ion conductivity. According to one embodiment of the invention, under conditions of 80°C and 100% humidity, the chloride ion conductivity of the polymer oxygen reduction catalyst is 98-130 mS•cm. -1 For example, 98.5 mS•cm -1 98.9 mS•cm -1 99mS•cm -1 99.5 mS•cm -1 100mS•cm -1 102mS•cm -1 105mS•cm -1 108mS•cm -1 110mS•cm -1 113mS•cm -1 115mS•cm-1 120mS•cm -1 125mS•cm -1 126.8 mS•cm -1 Or 128 mS•cm -1 , and the range formed by any two of the above values.

[0052] The present invention will be described in detail below through embodiments.

[0053] In the following examples, unless specific experimental steps or conditions are specified, the procedures or conditions described in the literature in this field can be followed. Reagents or instruments whose manufacturers are not specified are all commercially available conventional reagent products. XRD patterns: Tested using a D / MAX-TTRIII(CBO) X-ray diffractometer (Rigaku Corporation, Japan), employing Cu Kα radiation (wavelength λ ≈ 1.5406 Å), with an operating voltage of 40 kV and a current of 200 mA. The diffraction angle ranged from 1.5° to 35° at 2θ, and the scan rate was 5° per minute. Infrared spectra: Infrared measurements were performed using a Bruker ALPHA spectrometer. Samples were prepared using the KBr pellet method, and the spectral acquisition range was 400-4000 cm⁻¹. -1 ; Nitrogen adsorption-desorption curves: Tested using a Micromeritics 3Flex adsorption analyzer at 77 K and a pressure range of 1 × 10⁻⁶. -5 Pa to 1 Pa. Samples were degassed under vacuum at 120°C for 12 hours before measurement. All samples were dried using a Samdri PVT-3D critical point desiccator from Tousimis, USA, before nitrogen adsorption-desorption isotherm measurements. The Nyquist curve was tested using the four-probe method; Electrochemical Testing: The oxygen reduction reaction performance of the samples was systematically evaluated using a CHI760E electrochemical workstation. All tests were performed in a standard three-electrode system with a 0.1 M KOH solution as the electrolyte. The three-electrode system consisted of a working electrode, a counter electrode, and a reference electrode. The working electrode was a glassy carbon rotating disk electrode (RDE) with the catalyst uniformly loaded on its surface. The reference electrode was a saturated calomel electrode, and the counter electrode was an inert graphite rod. LSV curves were measured in an O2 / N2 saturated 0.1 M KOH solution at a potential range of -1 to 0.1 V, with a scan rate of 10 mV•s. -1The rotational speed was 1600 rpm. Data such as initial potential, half-wave potential, and limiting current density were obtained. Elemental analysis was performed using a Vario EL CUBE elemental analyzer from Elementar GmbH, Germany, to determine the carbon (C), hydrogen (H), and nitrogen (N) content of the samples. Before testing, the samples were thoroughly dried under vacuum. XPS spectra were measured on a Thermo Nexsa G2 spectrometer. Electronic conductivity is measured using the Hall effect; R H =γ H / (q*n);ρ=1 / σ=1 / (q*n*μ);where R H Hall coefficient (cm) 3 / C), for electrons (n-type), R H It is negative; for holes (p-type) R H It is positive. This is the direct basis for determining the carrier type; γ H The Hall factor is a constant related to the scattering mechanism, typically between 0.8 and 1.2. q is the absolute value of the elementary charge (1.602 × 10⁻⁶). - ¹ 9 C); n is the effective carrier concentration (cm³) -3 ); ρ is the resistivity (ohm•cm); σ is the electrical conductivity (S•cm) –1 ); μ is the conductivity mobility (cm) 2 •V –1 •S –1 ).

[0054] The chloride ion conductivity σ is measured by anion conduction; the calculation formula is: σ=L / (RWd); where L is the distance between potential sensors, R is the membrane resistance, W is the membrane width, and d is the membrane thickness.

[0055] Figure 10-12 The lattice structure simulation data in the spectra were generated using Materials Studio (MS) software. The experimental data determination methods are the same as those used for XRD spectroscopy. Figure 1 To.

[0056] Example 1 (1) 10 mL of glass ampoule was filled with 1,2,4,5-phenyltetramine tetrahydrochloride (34 mg, 0.12 mmol) and perfluoroferrophthalocyanine (FePc) (51.4 mg, 0.06 mmol), followed by the addition of 3 mL of mesitylene and 1 mL of N,N-dimethylacetamide. The glass ampoule was sealed with a paraffin film and sonicated at 120 W for 10 minutes to obtain a homogeneous slurry. After adding 0.9 mL of triethylamine, the ampoule was immediately placed in liquid nitrogen for freezing until the liquid was completely solidified. The vacuum was then evacuated to a vacuum degree of 1 × 10⁻⁶. -5 Pa was maintained for 10 minutes, followed by thawing in a 25°C water bath until the solid completely liquefied. The mixture inside the ampoule was then degassed through a three-cycle freeze-vacuum-thaw cycle. During the third vacuum cycle, the glass ampoule was simultaneously evacuated and its opening was sealed with a flame, then allowed to stand at room temperature. At 120°C (2 K•min) -1 Heating for 5 days. After cooling to room temperature, the precipitate was collected and washed with THF / methanol solution (9 / 1 mL) by centrifugation-decantation cycle until the supernatant was nearly colorless. Finally, the supernatant was dried under vacuum in a Tousimis Samdri PVT-3D critical point desiccator using supercritical CO2 to obtain the metal phthalocyanine covalent organic material FePc-COF as a black powder (57.8 mg, yield 76%).

[0057] (2) FePc-COF (30 mg) and 3-bromopropyltrimethylammonium bromide (396 mg) were added to a dry 50 mL two-necked flask. The reaction system was degassed and purged with argon three times. 270 mL of anhydrous dichloromethane was deoxygenated with argon for 10 minutes and then injected into the flask. The mixture was stirred and refluxed at 40 °C for 2 days. After the reaction was completed and cooled to room temperature, the solid was collected by centrifugation. The solid was washed three times with a mixture of 6 mL water and 3 mL tetrahydrofuran and then dried under vacuum at 110 °C for 6 hours to obtain the polymer oxygen reduction catalyst (FePc-COF-lian / FePc-COF-lian-3C). The elemental analysis is shown in Table 1. The initial potential was 0.96 V, the half-wave potential was 0.84 V, the yield was 93%, and the electronic conductivity reached 1.71 S•m. -1 The chloride ion conductivity reached 126.828 mS•cm -1 It successfully integrates excellent dual electron and ion transport capabilities.

[0058] The XRD pattern of the polymer oxygen reduction catalyst is shown below. Figure 1 As shown, combined with Figure 1-3 It can be seen that post-modification has a structural optimization effect on FePc-COF and NiPc-COF, which can improve their crystallinity, but has the opposite effect on CuPc-COF, which has poor crystallinity after modification. Infrared spectra of 1,2,4,5-phenyltetramine tetrahydrochloride (BTM), perfluoroferrophthalocyanine, and polymer oxygen reduction catalysts are shown below. Figure 4 As shown, characteristic peaks attributable to CNC skeleton vibrations can be observed in the FePc-COF curve, indicating that covalent bonds are formed between the two monomers through condensation reaction. At the same time, the characteristic peaks of CF bonds from monomer FePc are present in the FePc-COF curve, indicating that the fluorine-modified phthalocyanine structure remains intact and is not destroyed during the polymerization process. The infrared spectra of the metal phthalocyanine covalent organic material (FePc-COF) in Comparative Example 1 and the polymer oxygen reduction catalyst (FePc-COF-lian) in Example 1 are as follows: Figure 5 As shown, the FePc-COF curve after modification with quaternary ammonium salt groups exhibits N-type ... + -C characteristic vibration peak.

[0059] XPS spectra of FePc-COF and FePc-COF-lian are as follows: Figure 9 As shown, Figures a, c, and e are the total spectrum of FePc-COF, N 1s, and Fe 2p, respectively; Figures b, d, and f are the total spectrum of FePc-COF-lian, N 1s, and Fe 2p, respectively. The XPS full spectra shown in Figures a and b reveal significant C 1s, N 1s, and O 1s characteristic peaks in both FePc-COF and FePc-COF-lian. These correspond to the basic components of the organic framework of the materials. In the FePc-COF-lian spectrum, a Br 3d characteristic peak is clearly observed at approximately 70 eV binding energy, directly originating from the bromine element acting as the counter ion in the grafted quaternary ammonium salt chain. This confirms the successful introduction of the quaternary ammonium salt group into the COF framework, achieving the expected functional modification. To further investigate the evolution of the nitrogen atom's chemical environment, we performed fine-tuning of the N 1s spectrum. From Figures c and d, three main components were identified: the peak at 398.5 eV is attributed to the C=N in the imine bond; the peak at 400.3 eV corresponds to the Fe-N bond coordinated with the central iron ion in the phthalocyanine ring; and the characteristic peak at 402.2 eV is attributed to the CN in the quaternary ammonium salt group. + A comparison of the N 1s spectra of FePc-COF-lian and FePc-COF clearly shows that CN +The peaks of the components appeared significantly only in the functionalized materials, confirming that the quaternary ammonium salt cations were successfully modified at the nitrogen sites of the COF framework, achieving the expected chemical structure design. Figures e and f verify the valence state of iron in FePc-COF and FePc-COF-lian, respectively. In the Fe 2p spectrum of FePc-COF, two peaks were observed at 711.5 and 724.2 eV, which can be attributed to Fe 3+ Fe 2p 3 / 2 and Fe 2p 1 / 2 Orbital. Similarly, FePc-COF-lian also confirmed Fe 2p orbitals. 3 / 2 and Fe 2p 1 / 2 Fe 3+ The orbitals confirm that the Fe ions maintained the same valence state during the modification process (all elemental spectra were corrected for over-electron binding energy with the C1s valence band binding energy of 284.8 eV as a reference standard).

[0060] The Nyquist curve of the polymer oxygen reduction catalyst is shown below. Figure 7 As shown, the chloride ion conductivity of the materials was measured using four-probe electrochemical impedance spectroscopy (EIS). Under conditions of 80℃ and 100% humidity, the chloride ion conductivity of FePc-COF, CuPc-COF, and NiPc-COF were 4.595 mS•cm. -1 5.112 mS•cm -1 and 4.159 mS•cm -1 The chloride ion transport performance of MPc-COF-lian materials functionalized with quaternary ammonium salt chains was improved by orders of magnitude: under the same conditions, the conductivity of FePc-COF-lian, CuPc-COF-lian, and NiPc-COF-lian was significantly increased to 126.828 mS•cm. -1 113.110 mS•cm -1 and 98.914 mS•cm -1 This confirms that quaternary ammonium salt modification helps improve the ion conductivity of COF materials; The LSV curve of the polymer oxygen reduction catalyst is shown in the figure. Figure 8 As shown, longer ionic side chains are not necessarily more conducive to electron and ion transport. When the side chain length is three carbons (propyl), the material exhibits the best ORR catalytic performance.

[0061] Example 2 Similar to Example 1, except that 0.06 mmol of perfluoroferrophthalocyanine iron was replaced with 0.06 mmol of perfluorocopper phthalocyanine (CuPc) (51.6 mg); the resulting polymer oxygen reduction catalyst (CuPc-COF-lian) was analyzed as shown in Table 1, with an onset potential of 0.836 V, a half-wave potential of 0.651 V, and an electronic conductivity of 0.82 S•m. -1 The chloride ion conductivity is 113.110 mS•cm -1 .

[0062] The XRD pattern of the polymer oxygen reduction catalyst is shown below. Figure 2 As shown, combined with Figure 1-3 It can be seen that post-modification has a structural optimization effect on FePc-COF and NiPc-COF, which can improve their crystallinity, but has the opposite effect on CuPc-COF, which has poor crystallinity after modification. The Nyquist curve of the polymer oxygen reduction catalyst is shown below. Figure 7 As shown, the chloride ion conductivity of the materials was measured using four-probe electrochemical impedance spectroscopy (EIS). Under conditions of 80℃ and 100% humidity, the chloride ion conductivity of FePc-COF, CuPc-COF, and NiPc-COF were 4.595 mS•cm. -1 5.112 mS•cm -1 and 4.159 mS•cm -1 The chloride ion transport performance of MPc-COF-lian materials functionalized with quaternary ammonium salt chains was improved by orders of magnitude: under the same conditions, the conductivity of FePc-COF-lian, CuPc-COF-lian, and NiPc-COF-lian was significantly increased to 126.828 mS•cm. -1 113.110 mS•cm -1 and 98.914 mS•cm -1 This study confirmed that quaternary ammonium salt modification helps improve the ion conductivity of COF materials.

[0063] Example 3 Similar to Example 1, except that 0.06 mmol of perfluoroiron phthalocyanine was replaced with 0.06 mmol of perfluoronickel phthalocyanine (NiPc) (51.4 mg); the resulting polymer oxygen reduction catalyst (NiPc-COF-lian) was analyzed as shown in Table 1, with an onset potential of 0.865 V, a half-wave potential of 0.681 V, and an electronic conductivity of 0.92 S•m. -1 The chloride ion conductivity is 98.914 mS•cm. -1 .

[0064] The XRD pattern of the polymer oxygen reduction catalyst is shown below. Figure 3 As shown, combined with Figure 1-3 It can be seen that post-modification has a structural optimization effect on FePc-COF and NiPc-COF, which can improve their crystallinity, but has the opposite effect on CuPc-COF, which has poor crystallinity after modification. The nitrogen adsorption-desorption curves of the metal phthalocyanine covalent organic material (NiPc-COF) in Comparative Example 3 and the polymer oxygen reduction catalyst (NiPc-COF-lian) in Example 3 are shown in the figure below. Figure 6 As shown, the maximum BET specific surface area of ​​NiPc-COF powder is 95 m². 2 •g -1 The maximum BET specific surface area of ​​the post-modified NiPc-COF-lian powder is 75 m². 2 •g -1 For structures with different central atoms, the introduction of ionic chains reduces the BET specific surface area of ​​COF powder, and the presence of side chain groups hinders N2 molecules from entering the crystal framework.

[0065] The Nyquist curve of the polymer oxygen reduction catalyst is shown below. Figure 7 As shown, the chloride ion conductivity of the materials was measured using four-probe electrochemical impedance spectroscopy (EIS). Under conditions of 80℃ and 100% humidity, the chloride ion conductivity of FePc-COF, CuPc-COF, and NiPc-COF were 4.595 mS•cm. -1 5.112 mS•cm -1 and 4.159 mS•cm -1 The chloride ion transport performance of MPc-COF-lian materials functionalized with quaternary ammonium salt chains was improved by orders of magnitude: under the same conditions, the conductivity of FePc-COF-lian, CuPc-COF-lian, and NiPc-COF-lian was significantly increased to 126.828 mS•cm. -1 113.110 mS•cm -1 and 98.914 mS•cm -1 This study confirmed that quaternary ammonium salt modification helps improve the ion conductivity of COF materials.

[0066] Example 4 Same as in Example 1, except that 396 mg of 3-bromopropyltrimethylammonium bromide was replaced with 396 mg of (2-bromoethyl)-trimethylammonium bromide; a polymer oxygen reduction catalyst (FePc-COF-lian-2C) was obtained with an onset potential of 0.95 V and a half-wave potential of 0.83 V.

[0067] The LSV curve of the polymer oxygen reduction catalyst is shown in the figure. Figure 8 As shown, longer ionic side chains are not necessarily more conducive to electron and ion transport. When the side chain length is three carbons (propyl), the material exhibits the best ORR catalytic performance.

[0068] Example 5 Same as in Example 1, except that 396 mg of 3-bromopropyltrimethylammonium bromide was replaced with 396 mg of (4-bromobutyl)-trimethylammonium bromide; the polymer oxygen reduction catalyst (FePc-COF-lian-4C) was obtained with an onset potential of 0.95 V and a half-wave potential of 0.83 V.

[0069] The LSV curve of the polymer oxygen reduction catalyst is shown in the figure. Figure 8 As shown, longer ionic side chains are not necessarily more conducive to electron and ion transport. When the side chain length is three carbons (propyl), the material exhibits the best ORR catalytic performance.

[0070] Example 6 Same as Example 1, except that 396 mg of 3-bromopropyltrimethylammonium bromide was replaced with 396 mg of (6-bromohexyl)-trimethylammonium bromide; the polymer oxygen reduction catalyst (FePc-COF-lian-6C) was obtained with an onset potential of 0.94 V and a half-wave potential of 0.79 V.

[0071] The LSV curve of the polymer oxygen reduction catalyst is shown in the figure. Figure 8 As shown, longer ionic side chains are not necessarily more conducive to electron and ion transport. When the side chain length is three carbons (propyl), the material exhibits the best ORR catalytic performance.

[0072] Comparative Example 1 A 10 mL glass ampoule was filled with 1,2,4,5-phenyltetramine tetrahydrochloride (34 mg, 0.12 mmol) and perfluoroferrophthalocyanine (FePc) (51.4 mg, 0.06 mmol), followed by the addition of 3 mL of trimethylolpropene and 1 mL of N,N-dimethylacetamide. The ampoule was sealed with a paraffin film and sonicated at 120 W for 10 minutes to obtain a homogeneous slurry. 0.9 mL of triethylamine was added, and the ampoule was immediately placed in liquid nitrogen for freezing until the liquid was completely solidified. A vacuum of 1 × 10⁻⁶ was then applied. -5 Pa was maintained for 10 minutes, followed by thawing in a 25°C water bath until the solid completely liquefied. The mixture inside the ampoule was then degassed through a three-cycle freeze-vacuum-thaw cycle. During the third vacuum cycle, the glass ampoule was simultaneously evacuated and its opening was sealed with a flame, then allowed to stand at room temperature. At 120°C (2 K•min) -1Heating for 5 days. After cooling to room temperature, the precipitate was collected and washed with THF / methanol solution (9 / 1 mL) by centrifugation-decantation cycle until the supernatant was nearly colorless. Finally, the supernatant was dried under vacuum in a Tousimis Samdri PVT-3D critical point desiccator using supercritical CO2 to obtain the metal phthalocyanine covalent organic material FePc-COF as a black powder.

[0073] The elemental analysis of the metal phthalocyanine covalent organic material FePc-COF is shown in Table 1. The onset potential is 0.94 V, the half-wave potential is 0.78 V, and the electronic conductivity is 0.15 S•m. -1 The chloride ion conductivity is 4.595 mS•cm -1 The yield was 76%.

[0074] XRD patterns of metal phthalocyanine covalent organic materials are shown below. Figure 1 As shown, combined with Figure 1-3 It can be seen that post-modification has a structural optimization effect on FePc-COF and NiPc-COF, improving their crystallinity, but has the opposite effect on CuPc-COF, causing its crystallinity to deteriorate after modification; the experimental and simulated data of the crystal structure (XRD pattern) of the metal phthalocyanine covalent organic materials are as follows: Figure 10 As shown, simulations using Materials Studio software demonstrate that the experimental data and theoretical simulations of FePc-COF are in good agreement.

[0075] The infrared spectra of the metal phthalocyanine covalent organic material (FePc-COF) in Comparative Example 1 and the polymer oxygen reduction catalyst (FePc-COF-lian) in Example 1 are as follows: Figure 5 As shown, the FePc-COF curve after modification with quaternary ammonium salt groups exhibits N-type ... + -C characteristic vibration peak.

[0076] XPS spectra of FePc-COF and FePc-COF-lian are as follows: Figure 9As shown, Figures a, c, and e are the total spectrum of FePc-COF, N 1s, and Fe 2p, respectively; Figures b, d, and f are the total spectrum of FePc-COF-lian, N 1s, and Fe 2p, respectively. The XPS full spectra shown in Figures a and b reveal significant C 1s, N 1s, and O 1s characteristic peaks in both FePc-COF and FePc-COF-lian. These correspond to the basic components of the organic framework of the materials. In the FePc-COF-lian spectrum, a Br 3d characteristic peak is clearly observed at approximately 70 eV binding energy, directly originating from the bromine element acting as the counter ion in the grafted quaternary ammonium salt chain. This confirms the successful introduction of the quaternary ammonium salt group into the COF framework, achieving the expected functional modification. To further investigate the evolution of the nitrogen atom's chemical environment, we performed fine-tuning of the N 1s spectrum. From Figures c and d, three main components were identified: the peak at 398.5 eV is attributed to the C=N in the imine bond; the peak at 400.3 eV corresponds to the Fe-N bond coordinated with the central iron ion in the phthalocyanine ring; and the characteristic peak at 402.2 eV is attributed to the CN in the quaternary ammonium salt group. + A comparison of the N 1s spectra of FePc-COF-lian and FePc-COF clearly shows that CN + The peaks of the components appeared significantly only in the functionalized materials, confirming that the quaternary ammonium salt cations were successfully modified at the nitrogen sites of the COF framework, achieving the expected chemical structure design. Figures e and f verify the valence state of iron in FePc-COF and FePc-COF-lian, respectively. In the Fe 2p spectrum of FePc-COF, two peaks were observed at 711.5 and 724.2 eV, which can be attributed to Fe 3+ Fe 2p 3 / 2 and Fe 2p 1 / 2 Orbital. Similarly, FePc-COF-lian also confirmed Fe 2p orbitals. 3 / 2 and Fe 2p 1 / 2 Fe 3+ The orbitals confirm that the Fe ions maintained the same valence state during the modification process (all elemental spectra were corrected for over-electron binding energy with the C1s valence band binding energy of 284.8 eV as a reference standard).

[0077] The Nyquist curve of covalent organic metal phthalocyanine materials is shown below. Figure 7 As shown, the chloride ion conductivity of the materials was measured using four-probe electrochemical impedance spectroscopy (EIS). Under conditions of 80℃ and 100% humidity, the chloride ion conductivity of FePc-COF, CuPc-COF, and NiPc-COF were 4.595 mS•cm.-1 5.112 mS•cm -1 and 4.159 mS•cm -1 The chloride ion transport performance of MPc-COF-lian materials functionalized with quaternary ammonium salt chains was improved by orders of magnitude: under the same conditions, the conductivity of FePc-COF-lian, CuPc-COF-lian, and NiPc-COF-lian was significantly increased to 126.828 mS•cm. -1 113.110 mS•cm -1 and 98.914 mS•cm -1 This confirms that quaternary ammonium salt modification helps improve the ion conductivity of COF materials; The LSV curve of the polymer oxygen reduction catalyst is shown in the figure. Figure 8 As shown, longer ionic side chains are not necessarily more conducive to electron and ion transport. When the side chain length is three carbons (propyl), the material exhibits the best ORR catalytic performance.

[0078] Comparative Example 2 CuPc-COF was prepared using the same method as in Example 2.

[0079] The elemental analysis of the metal phthalocyanine covalent organic material CuPc-COF is shown in Table 1. The onset potential is 0.819 V, the half-wave potential is 0.612 V, and the electronic conductivity is 0.19 S•m. -1 The chloride ion conductivity is 5.112 mS•cm -1 The yield was 72%.

[0080] XRD patterns of metal phthalocyanine covalent organic materials are shown below. Figure 2 As shown, combined with Figure 1-3 It can be seen that post-modification has a structural optimization effect on FePc-COF and NiPc-COF, improving their crystallinity, but has the opposite effect on CuPc-COF, causing its crystallinity to deteriorate after modification; the experimental and simulated data of the crystal structure (XRD pattern) of the metal phthalocyanine covalent organic materials are as follows: Figure 11 As shown, simulations using Materials Studio software demonstrate that the experimental data and theoretical simulations of CuPc-COF are in good agreement.

[0081] The Nyquist curve of covalent organic metal phthalocyanine materials is shown below. Figure 7 As shown, the chloride ion conductivity of the materials was measured using four-probe electrochemical impedance spectroscopy (EIS). Under conditions of 80℃ and 100% humidity, the chloride ion conductivity of FePc-COF, CuPc-COF, and NiPc-COF were 4.595 mS•cm. -15.112 mS•cm -1 and 4.159 mS•cm -1 The chloride ion transport performance of MPc-COF-lian materials functionalized with quaternary ammonium salt chains was improved by orders of magnitude: under the same conditions, the conductivity of FePc-COF-lian, CuPc-COF-lian, and NiPc-COF-lian was significantly increased to 126.828 mS•cm. -1 113.110 mS•cm -1 and 98.914 mS•cm -1 This study confirmed that quaternary ammonium salt modification helps improve the ion conductivity of COF materials.

[0082] Comparative Example 3 NiPc-COF was prepared using the same method as in Example 3.

[0083] The elemental analysis of the metal phthalocyanine covalent organic material NiPc-COF is shown in Table 1. The onset potential is 0.834 V, the half-wave potential is 0.645 V, and the electronic conductivity is 0.67 S•m. -1 The chloride ion conductivity is 4.159 mS•cm -1 The yield was 74%.

[0084] XRD patterns of metal phthalocyanine covalent organic materials are shown below. Figure 3 As shown, combined with Figure 1-3 It can be seen that post-modification has a structural optimization effect on FePc-COF and NiPc-COF, improving their crystallinity, but has the opposite effect on CuPc-COF, causing its crystallinity to deteriorate after modification; the experimental and simulated data of the crystal structure (XRD pattern) of the metal phthalocyanine covalent organic materials are as follows: Figure 12 As shown, simulations using Materials Studio software demonstrate that the experimental data and theoretical simulations of NiPc-COF are in good agreement.

[0085] The nitrogen adsorption-desorption curves of the metal phthalocyanine covalent organic material (NiPc-COF) in Comparative Example 3 and the polymer oxygen reduction catalyst (NiPc-COF-lian) in Example 3 are shown in the figure below. Figure 6 As shown, the maximum BET specific surface area of ​​NiPc-COF powder is 95 m². 2 •g -1 The maximum BET specific surface area of ​​the post-modified NiPc-COF-lian powder is 75 m². 2 •g -1For structures with different central atoms, the introduction of ionic chains reduces the BET specific surface area of ​​COF powder, and the presence of side chain groups hinders N2 molecules from entering the crystal framework. The Nyquist curve of covalent organic metal phthalocyanine materials is shown below. Figure 7 As shown, the chloride ion conductivity of the materials was measured using four-probe electrochemical impedance spectroscopy (EIS). Under conditions of 80℃ and 100% humidity, the chloride ion conductivity of FePc-COF, CuPc-COF, and NiPc-COF were 4.595 mS•cm. -1 5.112 mS•cm -1 and 4.159 mS•cm -1 The chloride ion transport performance of MPc-COF-lian materials functionalized with quaternary ammonium salt chains was improved by orders of magnitude: under the same conditions, the conductivity of FePc-COF-lian, CuPc-COF-lian, and NiPc-COF-lian was significantly increased to 126.828 mS•cm. -1 113.110 mS•cm -1 and 98.914 mS•cm -1 This study confirmed that quaternary ammonium salt modification helps improve the ion conductivity of COF materials.

[0086] Table 1

[0087] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A polymer oxygen reduction catalyst, characterized in that, The catalyst has structural units as shown in formula (I): Equation (I); In formula (I), M is selected from at least one of Fe, Ni, and Cu; R is a C1-C6 alkylene group; X is a halogen; Z1, Z2, Z3, and Z4 are each independently selected from one of N, O, and S; Y is H or -RN. + (CH3)3 X ˉ , where R is a C1-C6 alkylene group, X is a halogen, and * indicates a connecting end; When Z1, Z2, Z3, and Z4 are each independently N, Y is -RN. + (CH3)3 X ˉ When Z1, Z2, Z3, and Z4 are each independently O or S, Y is H.

2. The catalyst according to claim 1, wherein, M is Fe and / or Ni, preferably Fe; and / or R is a C2-C4 alkylene group, preferably at least one of ethylene, propyleneene, and butylene, more preferably propyleneene; and / or X is Cl and / or Br, preferably Br; and / or Z1, Z2, Z3, and Z4 are each independently N.

3. The catalyst according to claim 1 or 2, wherein, The onset potential of the polymer oxygen reduction catalyst is 0.8-1V; and / or The polymer oxygen reduction catalyst has a half-wave potential of 0.6-0.9V; and / or The polymer oxygen reduction catalyst has an electronic conductivity of 0.8-1.8 S•m. -1 ; and / or The chloride ion conductivity of the polymer oxygen reduction catalyst is 98-130 mS•cm. -1 .

4. A method for preparing a polymer oxygen reduction catalyst, characterized in that, The method includes: S1. Nitrogen-containing organic ligands, perfluorinated metal phthalocyanines and solvents are mixed, and then an alkaline catalyst is added to carry out a freeze-vacuum-thaw cycle. The reaction is carried out under sealed conditions, and after purification and drying, the metal phthalocyanine covalent organic material is obtained. S2. In the presence of an inert gas, a covalent organic metal phthalocyanine, a quaternary ammonium salt, and an organic solvent are brought into contact for an alkylation reaction. The nitrogen-containing organic ligand is selected from at least one of 1,2,4,5-phenyltetramine tetrahydrochloride, 2,5-diamino-1,4-phenyldithiophene dihydrochloride and 2,5-diamino-1,4-dihydroxyphenyl dihydrochloride; The perfluorinated metal phthalocyanine is selected from at least one of perfluorinated iron phthalocyanine, perfluorinated copper phthalocyanine, and perfluorinated nickel phthalocyanine; The general structural formula of the quaternary ammonium salt is XRN. + (CH3)3 X ˉ R is a C1-C6 alkylene group, and X is a halogen.

5. The method according to claim 4, wherein, The nitrogen-containing organic ligand is 1,2,4,5-phenyltetramine tetrahydrochloride; and / or The perfluorometal phthalocyanine is perfluorophthalocyanine iron and / or perfluorophthalocyanine nickel, preferably perfluorophthalocyanine iron; and / or The solvent is an organic solvent, preferably selected from at least two of mesitylene, N,N-dimethylacetamide, 1,4-dioxane, toluene, N,N-dimethylformamide, o-dichlorobenzene, and n-butanol, more preferably mesitylene and N,N-dimethylacetamide, with a volume ratio of 1-5:1; and / or The alkaline catalyst is selected from at least one of triethylamine, ammonia, and trimethylamine; preferably triethylamine; and / or The molar ratio of the nitrogen-containing organic ligand to the perfluorinated metal phthalocyanine is 1-3:1; and / or The molar ratio of the solvent to the perfluorinated metal phthalocyanine is 0.1-1:1; and / or The molar ratio of the alkaline catalyst to the perfluorinated metal phthalocyanine is 0.05-0.2:

1.

6. The method according to claim 4 or 5, wherein, The mixing of the nitrogen-containing organic ligand, the perfluorinated metal phthalocyanine and the solvent is carried out under sealed conditions and with ultrasonic assistance. Preferably, the ultrasonic power is 100-150W and the time is 5-15min. and / or and / or The conditions for the contact reaction include a temperature of 100-140℃ and a time of 3-6 days.

7. The method according to any one of claims 4-6, wherein, In the general formula of the quaternary ammonium salt, R is a C2-C4 alkylene group, preferably at least one of ethylene, propyleneene, and butylene, more preferably propyleneene; and / or In the general formula of the quaternary ammonium salt structure, X is Cl and / or Br, preferably Br; Preferably, The quaternary ammonium salt is selected from at least one of (2-bromoethyl)-trimethylammonium bromide, (3-bromopropyl)-trimethylammonium bromide, and (4-bromobutyl)-trimethylammonium bromide, preferably (3-bromopropyl)-trimethylammonium bromide; and / or The organic solvent is selected from dichloromethane and / or N,N-dimethylformamide, preferably dichloromethane.

8. The method according to any one of claims 4-7, wherein, The mass ratio of the metal phthalocyanine covalent organic material to the quaternary ammonium salt is 1:5-20; and / or The conditions for alkylation reaction include a temperature of 25-60℃ and a time of 1-3 days.

9. A polymer oxygen reduction catalyst prepared by the method according to any one of claims 4-8.

10. The polymer oxygen reduction catalyst according to claim 9, wherein, The onset potential of the polymer oxygen reduction catalyst is 0.8-1V; and / or The polymer oxygen reduction catalyst has a half-wave potential of 0.6-0.9V; and / or The polymer oxygen reduction catalyst has an electronic conductivity of 0.8-1.8 S•m. -1 ; and / or The chloride ion conductivity of the polymer oxygen reduction catalyst is 98-130 mS•cm. -1 .

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