Polyphthalocyanine / metal oxide composite catalyst as well as preparation method and application thereof

Abstract

The invention relates to the technical field of catalyst preparation, and discloses a polyphthalocyanine / metal oxide composite catalyst as well as a preparation method and application thereof. The composite catalyst comprises a carbon carrier and metal polyphthalocyanine loaded on the carbon carrier; wherein the carbon carrier is a carbon material modified by metal oxide nanoparticles. The polyphthalocyanine / metal oxide composite catalyst provided by the invention can form a double-electron exchange channel, can effectively stabilize a metal active site in the center of polyphthalocyanine through electron transfer, remarkably inhibits dissolution and inactivation of the polyphthalocyanine in a severe environment, and has high catalytic activity and high stability.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, specifically to a polyphthalocyanine / metal oxide composite catalyst, its preparation method, and its application. Background Technology

[0002] In fields such as fuel cells, metal-air batteries, and the chlor-alkali industry, the slow oxygen reduction reaction kinetics at the cathode severely restricts the overall performance and development of electrochemical devices. Currently, although platinum-carbon catalysts are widely used to accelerate the oxygen reduction reaction at the cathode, their high cost, resource scarcity, and the susceptibility to carbon support corrosion and platinum particle migration and agglomeration during the reaction significantly limit large-scale commercialization. Therefore, developing non-precious metal catalysts that combine high activity and high stability is crucial.

[0003] Metal polyphthalocyanines are considered highly promising alternative materials due to their low cost and excellent conductivity. However, under harsh working environments (such as high electrode potentials, strong acidic and alkaline electrolytes), the non-noble metal active centers on and near the surface of these catalysts are prone to dissolution or deactivation, leading to catalyst performance degradation. Therefore, researching and developing highly active and stable metal polyphthalocyanine-based oxygen reduction catalysts and their preparation methods is of scientific significance and practical value. Summary of the Invention

[0004] The purpose of this invention is to solve the problem of high catalyst cost in the cathode oxygen reduction reaction process in related fields, while ensuring its high catalytic activity and high stability, and to provide a polyphthalocyanine / metal oxide composite catalyst, its preparation method and application.

[0005] In this invention, the preparation method of the polyphthalocyanine / metal oxide composite catalyst has the advantages of simple process, strong controllability, and ease of large-scale production. This is achieved by introducing the metal oxide M1O... x The support forms an M1-O-M2 bimetallic exchange interaction with the central metal M2 of polyphthalocyanine. This interaction induces directional electron jumping in the M1-O-M2 coordination structure, leading to charge redistribution and significantly increasing the electron spin density of the central metal M2 of polyphthalocyanine. This oxide-supported polyphthalocyanine composite catalyst precisely modulates the local coordination environment of the central metal of polyphthalocyanine, optimizes the intrinsic activity of the reactive sites, enhances the skeletal stability of the catalyst, and inhibits the dissolution of the metal active center.

[0006] To achieve the above objectives, the first aspect of the present invention provides a polyphthalocyanine / metal oxide composite catalyst, wherein the composite catalyst comprises a carbon support and a metal polyphthalocyanine supported on the carbon support; The carbon support is a carbon material modified with metal oxide nanoparticles.

[0007] A second aspect of the present invention provides a method for preparing the composite catalyst according to the first aspect, wherein the method includes the following steps: (1) The metal oxide precursor is added to the carbon material solution for mixing and first heating, then adjusted to acidity and second heating, and then post-processed to obtain carbon material modified with metal oxide nanoparticles, which serves as a carbon carrier. (2) The carbon support and metal polyphthalocyanine obtained in step (1) are dispersed in a solvent, mixed and then post-treated to obtain the polyphthalocyanine / metal oxide composite catalyst.

[0008] A third aspect of the present invention provides a polyphthalocyanine / metal oxide composite catalyst prepared according to the preparation method described in the second aspect.

[0009] The fourth aspect of the present invention provides the use of the polyphthalocyanine / metal oxide composite catalyst according to the first or third aspect as an oxygen reduction catalyst in acidic or alkaline media.

[0010] The fifth aspect of the present invention provides a metal-air battery comprising the polyphthalocyanine / metal oxide composite catalyst described in the first or third aspect as a cathode coating.

[0011] The beneficial technical effects achieved by the present invention through the above technical solution are as follows: (1) The polyphthalocyanine / metal oxide composite catalyst provided by the present invention can form a dual electron exchange channel, which can effectively stabilize the metal active site of the polyphthalocyanine center through electron transfer, significantly inhibit its dissolution and deactivation in harsh environments, and has high catalytic activity and high stability.

[0012] (2) The present invention first modifies the surface of carbon material with metal oxide nanoparticles in situ as carbon carrier, and then loads metal polyphthalocyanine onto the carbon material modified with metal oxide nanoparticles through a post-loading process. The operation is simple and the cost is low.

[0013] (3) This invention can be widely applied to fuel cells, metal-air batteries and other fields. Attached Figure Description

[0014] Figure 1 This is a thermogravimetric analysis (TGA) diagram of Ketjen Black modified with titanium dioxide nanoparticles prepared in Example 1 of this invention.

[0015] Figure 2 This is a transmission electron microscope image of the polyphthalocyanine iron / metal oxide composite catalyst prepared in Example 1 of the present invention.

[0016] Figure 3This is a spherical aberration electron microscope image of polyphthalocyanine iron loaded onto metal oxide nanoparticles in the polyphthalocyanine iron / metal oxide composite catalyst prepared in Example 1 of this invention.

[0017] Figure 4 This is the X-ray diffraction pattern of the polyphthalocyanine iron / metal oxide composite catalyst prepared in Example 1 of this invention.

[0018] Figure 5 This is a scanning electron microscope image of the polyphthalocyanine cobalt / metal oxide composite catalyst prepared in Example 2 of the present invention.

[0019] Figure 6 This is a scanning electron microscope image of the polyphthalocyanine nickel / metal oxide composite catalyst prepared in Example 3 of the present invention.

[0020] Figure 7 This is a scanning electron microscope image of the polyphthalocyanine copper / metal oxide composite catalyst prepared in Example 4 of the present invention.

[0021] Figure 8 The image shows the rotating circular disk curve of the activity test of the polyphthalocyanine iron / metal oxide composite catalyst prepared in Example 1 of this invention in 0.1 M KOH.

[0022] Figure 9 The image shows the rotating circular disk curves of the activity test of the polyphthalocyanine iron / metal oxide composite catalyst prepared in Example 1 of this invention in 0.1 M HClO4.

[0023] Figure 10 This is a rotating disk curve of the stability test of the polyphthalocyanine iron / metal oxide composite catalyst prepared in Example 1 of the present invention in 0.1 M KOH.

[0024] Figure 11 This is a rotating disk curve of the stability test of the polyphthalocyanine iron / metal oxide composite catalyst prepared in Example 1 of the present invention in 0.1 M HClO4. Detailed Implementation

[0025] 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.

[0026] The first aspect of the present invention provides a polyphthalocyanine / metal oxide composite catalyst, wherein the composite catalyst comprises a carbon support and a metal polyphthalocyanine supported on the carbon support; The carbon support is a carbon material modified with metal oxide nanoparticles.

[0027] The polyphthalocyanine / metal oxide composite catalyst of the present invention is in the form of a black solid powder, wherein the metal oxide is distributed on the carbon material in the form of nanoparticles as a carbon support, the metal polyphthalocyanine is selectively loaded onto the metal oxide nanoparticles rather than onto the carbon material, and its central metal exists in the form of a single atom.

[0028] In some embodiments of the present invention, the central metal of the metal polyphthalocyanine is in the form of a single atom.

[0029] In some embodiments of the present invention, the carbon material is selected from at least one of Vulcan-72, Ketjen Black, BP-2000, carbon nanotubes, and graphene.

[0030] In some embodiments of the present invention, the metal oxide nanoparticles are selected from at least one of titanium dioxide nanoparticles, zirconium dioxide nanoparticles, and cerium dioxide nanoparticles.

[0031] In some embodiments of the present invention, the average particle size of the metal oxide nanoparticles is 2-15 nm, preferably 10 nm.

[0032] In some embodiments of the present invention, the metal polyphthalocyanine is selected from at least one of polyphthalocyanine iron, polyphthalocyanine cobalt, polyphthalocyanine nickel, and polyphthalocyanine copper.

[0033] In some embodiments of the present invention, the mass percentage of metal oxide nanoparticles in the carbon support is 5-20%, preferably 15%.

[0034] In some embodiments of the present invention, the mass ratio of carbon support to metal polyphthalocyanine is 1:5-2:1, such as 1:5, 1:1, 2:1, etc., and any value within the range of any two of the above values, preferably 1:1.

[0035] A second aspect of the present invention provides a method for preparing the composite catalyst according to the first aspect, wherein the method includes the following steps: (1) The metal oxide precursor is added to the carbon material solution for mixing and first heating, then adjusted to acidity and second heating, and then post-processed to obtain carbon material modified with metal oxide nanoparticles, which serves as a carbon carrier. (2) The carbon support and metal polyphthalocyanine obtained in step (1) are dispersed in a solvent, mixed and then post-treated to obtain the polyphthalocyanine / metal oxide composite catalyst.

[0036] This invention first modifies carbon materials with metal oxide nanoparticles to obtain a carbon support, and then loads metal polyphthalocyanine onto the carbon support using a post-loading process. The composite catalyst prepared by this method exhibits a significantly enhanced spin degree of the metal at the center of the polyphthalocyanine, demonstrating excellent oxygen reduction performance in both acidic and alkaline media, making it suitable for metal-air batteries.

[0037] The composite catalyst provided by this invention is a multi-scale site catalyst, while the metal polyphthalocyanine is an atomic site catalyst, not a metallic state. In the metal polyphthalocyanine / metal oxide / carbon material composite system, there is a challenge regarding whether the polyphthalocyanine should be loaded onto the oxide or the carbon material. This invention achieves the distribution of polyphthalocyanine on the surface of oxide nanoparticles, rather than on the carbon material, through a sequential synthesis strategy of first constructing the metal oxide / carbon material and then utilizing the adsorption between the oxide surface and the polyphthalocyanine for secondary assembly.

[0038] In this invention, the first heating serves to promote the initial hydrolysis and condensation of the metal oxide precursor (e.g., tetrabutyl titanate) to form initial particles of metal hydroxide or oxide; the second heating serves to provide an acidic environment to promote the complete hydrolysis of the metal oxide precursor (e.g., tetrabutyl titanate) and promote the formation and crystallization of metal oxide particles.

[0039] In some embodiments of the present invention, in step (1), the metal oxide precursor is selected from at least one of tetrabutyl titanate, tetrapropyl zirconate and cerium ammonium nitrate.

[0040] In some embodiments of the present invention, the mass ratio of the metal oxide precursor to the carbon support is 1:3-2:1, for example 1:3, 0.5:1, 1:1, 2:1, etc., and any value within the range of any two of the above values.

[0041] In some embodiments of the present invention, a strong acid is added to make the pH of the system 1-4.

[0042] In some embodiments of the present invention, the strong acid is selected from at least one of nitric acid, hydrochloric acid, and sulfuric acid.

[0043] In some embodiments of the present invention, the concentration of the strong acid is 0.01-0.1 mol / L.

[0044] In some embodiments of the present invention, the conditions for the first heating and the second heating include: a water bath; the temperature is 60-100°C, preferably 80°C.

[0045] In some embodiments of the present invention, the first heating time is 20-40 minutes, preferably 30 minutes.

[0046] In some embodiments of the present invention, the second heating time is 1-3 hours.

[0047] In some embodiments of the present invention, in step (2), the mass ratio of carbon support to metal polyphthalocyanine is 1:5-2:1, for example 1:5, 1:1, 2:1, etc., and any value within the range of any two of the above values, preferably 1:1.

[0048] In some embodiments of the present invention, the solvent used in the carbon material solution in step (1) and the solvent in step (2) are each independently selected from at least one of ethanol, isopropanol and N,N-dimethylformamide.

[0049] In some embodiments of the present invention, the post-processing described in steps (1) and (2) includes: filtration, washing and drying.

[0050] According to a particularly preferred embodiment of the present invention, a method for preparing a polyphthalocyanine / metal oxide composite catalyst includes the following steps: (1) The carbon material was added to the solvent and dispersed to obtain a black suspension. Tetrabutyl titanate was added to it and ultrasonically dispersed until uniform. The suspension was then transferred to a water bath for the first heating. (2) After the first heating is completed, nitric acid is added and water bath heating is continued to promote the reaction. After the reaction is completed, the solution obtained by cooling is filtered, washed and dried to obtain carbon material modified with metal oxide nanoparticles as carbon carrier. (3) Disperse the carbon support and metal polyphthalocyanine obtained in step (2) into the solvent respectively, mix them after uniform dispersion, and continue ultrasonic dispersion to obtain a black suspension; (4) After filtering, washing and drying the black suspension obtained in step (3), the polyphthalocyanine / metal oxide composite catalyst is obtained.

[0051] In some embodiments of the present invention, the metal polyphthalocyanine is prepared by the following method: mixing pyromellitic anhydride, transition metal salt, ammonium chloride, ammonium molybdate and urea, and then calcining, washing and drying to obtain metal polyphthalocyanine.

[0052] In some embodiments of the present invention, the transition metal salt is a chloride salt, preferably selected from at least one of ferric chloride, cobalt chloride hexahydrate, nickel chloride hexahydrate, and copper chloride dihydrate.

[0053] In some embodiments of the present invention, the calcination conditions include: a temperature of 200-250°C and a time of 3-6 hours.

[0054] In some embodiments of the present invention, the washing is performed sequentially using water, ethanol, and dilute sulfuric acid.

[0055] Specifically, the metal polyphthalocyanine is prepared by the following method: using pyromellitic anhydride, chloride, ammonium chloride, ammonium molybdate and urea as raw materials, they are thoroughly mixed, placed in a crucible and heated in a muffle furnace at 200-250°C for 3-6 hours to carry out a solid-phase reaction, to obtain a black solid; the obtained solid is cooled to room temperature and washed successively with water, ethanol and dilute sulfuric acid; the washed solid is dried and cooled to obtain the metal polyphthalocyanine.

[0056] A third aspect of the present invention provides a polyphthalocyanine / metal oxide composite catalyst prepared according to the preparation method described in the second aspect.

[0057] The fourth aspect of the present invention provides the use of the polyphthalocyanine / metal oxide composite catalyst according to the first or third aspect as an oxygen reduction catalyst in acidic or alkaline media.

[0058] The fifth aspect of the present invention provides a metal-air battery comprising the polyphthalocyanine / metal oxide composite catalyst described in the first or third aspect as a cathode coating.

[0059] The present invention will be described in detail below through embodiments.

[0060] Unless otherwise specified in the following examples and comparative examples, all conditions were performed under standard conditions or conditions recommended by the manufacturer. Reagents or instruments used, unless otherwise specified, are all commercially available products.

[0061] Example 1 This example illustrates the preparation of a polyphthalocyanine / metal oxide composite catalyst.

[0062] (1) Using 2.1 g pyromellitic anhydride, 0.9 g ferric chloride, 1.0 g ammonium chloride, 0.05 g ammonium molybdate and 4.1 g urea as raw materials, they were thoroughly mixed, placed in a crucible and heated at 220 °C for 4 h in a muffle furnace to carry out a solid-phase reaction, and a black solid was obtained. The obtained solid was cooled to room temperature and washed with water, ethanol and dilute sulfuric acid in sequence. The washed solid was dried and cooled to obtain polyphthalocyanine iron. (2) Add 1.0g Ketjen black to 50mL ethanol, sonicate for 30min to obtain a black suspension, then add 1mL tetrabutyl titanate, continue sonication until uniform, transfer to a 60℃ water bath and heat for 30min. (3) Add 20 mL of 0.1 mol / L nitric acid to adjust the pH to about 1.5, continue heating in a water bath for 3 h to promote the reaction. After the reaction is completed, filter, wash and dry the solution obtained by cooling to obtain Ketjen Black modified with titanium dioxide nanoparticles. (4) Disperse 20 mg of Ketjen Black modified with titanium dioxide nanoparticles obtained in step (3) into ethanol, and disperse 100 mg of polyphthalocyanine iron into N,N-dimethylformamide. After uniform dispersion, mix and continue ultrasonic dispersion to obtain a black suspension. (5) The black suspension obtained in step (4) is filtered, washed and dried to obtain polyphthalocyanine iron / metal oxide composite catalyst.

[0063] Example 2 This example illustrates the preparation of a polyphthalocyanine / metal oxide composite catalyst.

[0064] (1) Using 2.1g pyromellitic anhydride, 1.2g cobalt chloride hexahydrate, 1.0g ammonium chloride, 0.05g ammonium molybdate and 4.1g urea as raw materials, they were thoroughly mixed, placed in a crucible and heated at 220°C in a muffle furnace for 4h to carry out a solid-phase reaction, and a black solid was obtained. The obtained solid was cooled to room temperature and washed with water, ethanol and dilute sulfuric acid in sequence. The washed solid was dried and cooled to obtain polyphthalocyanine cobalt. (2) Add 1.0g Ketjen black to 50mL ethanol, sonicate for 30min to obtain a black suspension, then add 500μL tetrabutyl titanate, continue to sonicate until uniform, transfer to an 80℃ water bath and heat for 30min. (3) Add 100 mL of 0.01 mol / L nitric acid to adjust the pH to about 2, continue heating in a water bath for 1 h to promote the reaction. After the reaction is completed, filter, wash and dry the solution obtained by cooling to obtain Ketjen Black modified with titanium dioxide nanoparticles. (4) Disperse 20 mg of Ketjen Black modified with titanium dioxide nanoparticles obtained in step (3) into ethanol, and disperse 100 mg of polyphthalocyanine cobalt into N,N-dimethylformamide. After uniform dispersion, mix and continue ultrasonic dispersion to obtain a black suspension. (5) The black suspension obtained in step (4) is filtered, washed and dried to obtain the polyphthalocyanine cobalt / metal oxide composite catalyst.

[0065] Example 3 This example illustrates the preparation of a polyphthalocyanine / metal oxide composite catalyst.

[0066] (1) Using 2.1g pyromellitic anhydride, 1.2g nickel chloride hexahydrate, 1.0g ammonium chloride, 0.05g ammonium molybdate and 4.1g urea as raw materials, they were thoroughly mixed, placed in a crucible and heated at 220°C in a muffle furnace for 4h to carry out a solid-phase reaction, and a black solid was obtained. The obtained solid was cooled to room temperature and washed with water, ethanol and dilute sulfuric acid in sequence. The washed solid was dried and cooled to obtain polyphthalocyanine nickel. (2) Add 1.0g Ketjen black to 50mL ethanol, sonicate for 30min to obtain a black suspension, then add 500μL tetrabutyl titanate, continue to sonicate until uniform, transfer to an 80℃ water bath and heat for 30min. (3) Add 100 mL of 0.01 mol / L nitric acid to adjust the pH to about 2, continue heating in a water bath for 1 h to promote the reaction. After the reaction is completed, filter, wash and dry the solution obtained by cooling to obtain Ketjen Black modified with titanium dioxide nanoparticles. (4) Disperse 100 mg of Ketjen Black modified with titanium dioxide nanoparticles obtained in step (3) into isopropanol and 100 mg of polyphthalocyanine nickel into N,N-dimethylformamide. After uniform dispersion, mix and continue ultrasonic dispersion to obtain a black suspension. (5) The black suspension obtained in step (4) is filtered, washed and dried to obtain the polyphthalocyanine nickel / metal oxide composite catalyst.

[0067] Example 4 This example illustrates the preparation of a polyphthalocyanine / metal oxide composite catalyst.

[0068] (1) Using 2.1g pyromellitic anhydride, 1.2g cobalt chloride, 1.0g copper chloride dihydrate, 0.05g ammonium molybdate and 4.1g urea as raw materials, they were thoroughly mixed, placed in a crucible and heated at 220°C in a muffle furnace for 4h for solid-phase reaction to obtain a black solid; the obtained solid was cooled to room temperature and washed with water, ethanol and dilute sulfuric acid in sequence; the washed solid was dried and cooled to obtain polyphthalocyanine copper; (2) Add 1.0g Vulcan-72 to 50mL ethanol, sonicate for 30min to obtain a black suspension, then add 2mL tetrabutyl titanate, continue to sonicate until uniform, transfer to a 100℃ water bath and heat for 30min. (3) Add 100 mL of 0.01 mol / L nitric acid to adjust the pH to about 2, continue heating in a water bath for 1 h to promote the reaction. After the reaction is completed, filter, wash and dry the solution obtained by cooling to obtain Vulcan-72 modified with titanium dioxide nanoparticles. (4) Disperse 20 mg of Vulcan-72 modified with titanium dioxide nanoparticles obtained in step (3) into ethanol, and disperse 100 mg of polyphthalocyanine copper into N,N-dimethylformamide. After uniform dispersion, mix and continue ultrasonic dispersion to obtain a black suspension. (5) The black suspension obtained in step (4) is filtered, washed and dried to obtain the polyphthalocyanine copper / metal oxide composite catalyst.

[0069] Comparative Example 1 This comparative example prepared Ketjen black modified with titanium dioxide nanoparticles by steps (2) and (3) of Example 1.

[0070] Comparative Example 2 This comparative example prepared Ketjen black loaded with polyphthalocyanine iron (without metal oxide nanoparticle modification) through steps (4) and (5) of Example 1. The difference is that Ketjen black was directly used as the carrier of polyphthalocyanine iron in step (4).

[0071] Test Example 1: Morphological Characterization (1) Thermogravimetric analysis was performed on the Ketjen black modified with titanium dioxide nanoparticles prepared in Example 1 in air at a heating rate of 5 °C / min.

[0072] from Figure 1 It can be seen that the mass percentage of titanium dioxide nanoparticles in the carbon support is 15%.

[0073] (2) The polyphthalocyanine iron / metal oxide composite catalyst prepared in Example 1 was characterized and analyzed.

[0074] from Figure 2 It can be seen that the metal oxide nanoparticles are uniformly dispersed on the surface of the carbon material, with an average particle size of 10 nm. From... Figure 3 It can be seen that polyphthalocyanine iron is uniformly dispersed on the metal oxide nanoparticles in the form of atomic sites. From Figure 4 It can be seen that the prepared polyphthalocyanine iron / metal oxide composite catalyst was successfully prepared.

[0075] (3) The metal polyphthalocyanine / metal oxide composite catalysts prepared in Examples 2-4 were characterized and analyzed.

[0076] Figure 5-7 The prepared metal polyphthalocyanine / metal oxide composite catalysts exhibit similar morphological characteristics.

[0077] Test Example 2: Catalytic Activity Test Weigh 5 mg of the prepared catalyst and add it to 980 μL of ethanol and 20 μL of Nafion binder. Then, ultrasonically disperse the mixture for 2 hours to form a uniform black ink. Use a pipette to drop 10 μL of the black ink onto a surface with an area of ​​0.247 cm². 2 The electrode was placed on a disk electrode, and then tested using a rotating ring-disk electrode. The electrolyte was 0.1 M KOH and 0.1 M HClO4 saturated with O2, the counter electrode was a carbon rod, and the reference electrode was a saturated calomel electrode. Cyclic voltammetry was first performed for 20 cycles within the potential range of 0–1.23 V vs. RHE for activation, followed by linear sweep polarization curve testing.

[0078] from Figure 8 and 9 It can be seen that the half-wave potential of the prepared polyphthalocyanine iron / metal oxide composite catalyst was significantly improved compared with the control sample in the tests of 0.1 M KOH and 0.1 M HClO4 solutions.

[0079] Test Example 3: Stability Test Alkaline medium stability test: After 30,000 cycles of cyclic voltammetry test in the potential range of 0.65 V vs. RHE to 0.95 V vs. RHE using N2 saturated 0.1 M KOH electrolyte, the electrolyte was replaced with O2 saturated 0.1 M KOH electrolyte for linear sweep polarization curve test.

[0080] The acidic medium stability test is the same as the alkaline medium stability test, except that the electrolyte is replaced with 0.1 M HClO4 solution.

[0081] from Figure 10 It can be seen that the prepared polyphthalocyanine iron / metal oxide composite catalyst showed no decrease in half-wave potential after 30,000 cycles of cyclic voltammetry testing in 0.1 M KOH. Figure 11 It can be seen that the prepared polyphthalocyanine iron / metal oxide composite catalyst still maintains a high half-wave potential after 10,000 cycles of cyclic voltammetry testing in 0.1 M HClO4, and has excellent stability.

[0082] 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 polyphthalocyanine / metal oxide composite catalyst, characterized in that, The composite catalyst comprises a carbon support and a metal polyphthalocyanine supported on the carbon support; The carbon support is a carbon material modified with metal oxide nanoparticles.

2. The composite catalyst according to claim 1, wherein, The central metal of the metal polyphthalocyanine is in the form of a single atom; Preferably, the carbon material is selected from at least one of Vulcan-72, Ketjen Black, BP-2000, carbon nanotubes, and graphene; Preferably, the metal oxide nanoparticles are selected from at least one of titanium dioxide nanoparticles, zirconium dioxide nanoparticles, and cerium dioxide nanoparticles; Preferably, the average particle size of the metal oxide nanoparticles is 2-15 nm, and more preferably 10 nm; Preferably, the metal polyphthalocyanine is selected from at least one of polyphthalocyanine iron, polyphthalocyanine cobalt, polyphthalocyanine nickel, and polyphthalocyanine copper.

3. The composite catalyst according to claim 1 or 2, wherein, The mass percentage of metal oxide nanoparticles in the carbon support is 5-20%, preferably 15%; Preferably, the mass ratio of carbon support to metal polyphthalocyanine is 1:5-2:1, and more preferably 1:

1.

4. A method for preparing a composite catalyst according to any one of claims 1-3, characterized in that, The method includes the following steps: (1) The metal oxide precursor is added to the carbon material solution for mixing and first heating, then adjusted to acidity and second heating, and then post-processed to obtain carbon material modified with metal oxide nanoparticles, which serves as a carbon carrier. (2) The carbon support and metal polyphthalocyanine obtained in step (1) are dispersed in a solvent, mixed and then post-treated to obtain the polyphthalocyanine / metal oxide composite catalyst.

5. The preparation method according to claim 4, wherein, In step (1), the metal oxide precursor is selected from at least one of tetrabutyl titanate, tetrapropyl zirconate, and cerium ammonium nitrate; Preferably, the mass ratio of the metal oxide precursor to the carbon support is 1:3-2:1; Preferably, a strong acid is added to make the pH of the system 1-4; Preferably, the strong acid is selected from at least one of nitric acid, hydrochloric acid, and sulfuric acid; Preferably, the concentration of the strong acid is 0.01-0.1 mol / L; Preferably, the conditions for the first heating and the second heating include: a water bath; the temperature is 60-100℃, preferably 80℃; Preferably, the first heating time is 20-40 minutes, more preferably 30 minutes; Preferably, the second heating time is 1-3 hours; Preferably, in step (2), the mass ratio of carbon support to metal polyphthalocyanine is 1:5-2:1, preferably 1:

1.

6. The preparation method according to claim 4 or 5, wherein, The solvent used in the carbon material solution in step (1) and the solvent in step (2) are each independently selected from at least one of ethanol, isopropanol and N,N-dimethylformamide; Preferably, the post-processing described in steps (1) and (2) includes: filtration, washing and drying.

7. The preparation method according to any one of claims 4-6, wherein, The metal polyphthalocyanine is prepared by the following method: mixing pyromellitic anhydride, transition metal salt, ammonium chloride, ammonium molybdate and urea, and then calcining, washing and drying to obtain metal polyphthalocyanine; Preferably, the transition metal salt is a chloride salt, and is preferably selected from at least one of ferric chloride, cobalt chloride hexahydrate, nickel chloride hexahydrate, and copper chloride dihydrate; Preferably, the calcination conditions include: a temperature of 200-250℃ and a time of 3-6 h; Preferably, the washing process is carried out in sequence using water, ethanol, and dilute sulfuric acid.

8. A polyphthalocyanine / metal oxide composite catalyst prepared by the preparation method according to any one of claims 4-7.

9. The application of the polyphthalocyanine / metal oxide composite catalyst according to any one of claims 1-3 and 8 as an oxygen reduction catalyst in acidic or alkaline media.

10. A metal-air battery comprising the polyphthalocyanine / metal oxide composite catalyst as the cathode coating according to any one of claims 1-3 and 8.

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