A method for preparing a non-pyrolytic monatomic catalyst

Abstract

This invention discloses a method for preparing non-pyrolytic single-atom catalysts. A POP framework is synthesized from three monomers, and then transition metals (TM) and small molecule ligands are continuously modified onto the POPs via a simple two-step solvothermal reaction. The POPs catalyst prepared by this invention exhibits excellent oxygen reduction catalytic activity, with a half-wave potential of 0.830 V vs. RHE under alkaline conditions, and also demonstrates excellent 4-electron selectivity, with selectivity exceeding 90% in the potential range of 0.3–0.7 V vs. RHE.

Description

Technical Field

[0001] This invention belongs to the field of high-performance oxygen reduction electrocatalyst preparation technology, specifically relating to a method for preparing a non-pyrolytic single-atom catalyst, which is applied to the field of green energy storage and conversion devices represented by fuel cells and rechargeable metal-based batteries. Background Technology

[0002] Generally, the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are two critical processes for the normal operation of zinc oxide electrodes (ZABs). However, the achievable energy efficiency is severely limited by the slow reaction kinetics of OER and ORR at the air cathode during discharge and charge. To date, Pt-based ORR electrocatalysts have been considered ideal candidates for these two slow electrochemical reactions in air electrodes. However, insufficient availability and poor durability severely limit their application in zinc oxide electrodes. Application prospects in air batteries. To solve the above problems, there is an urgent need to develop non-precious metal-based electrocatalysts with high activity, high durability, and low cost.

[0003] In recent years, transition metal nitrogen-carbon (TM-NC) materials have been widely reported for oxygen reduction reaction (ORR). Due to their tunable electronic structure, abundant pores, and high stability, they have become a research hotspot for catalysts that can replace noble metals and are considered promising cathode materials for zinc-air batteries (ZABs). In TM-NCs, the high metal utilization and well-defined active centers of transition metal single-atom catalysts (SACs), along with their tunable electronic structure and atomic configurations with feasible surface modification capabilities, provide an ideal platform for designing highly efficient electrocatalysts. This is considered a promising approach to developing high-performance non-noble ZAB electrocatalysts.

[0004] However, the aperiodic structure and uncertain local environment of catalysts prepared by traditional pyrolysis methods have led to controversies regarding active centers. Therefore, model electrocatalysts with well-defined local coordination environments of active centers prepared by non-pyrolysis methods are of great significance for exploring the relationship between the ORR activity of catalysts and their local coordination environments. Porous organic compounds (POPs) (COFs, CTFs, COPs, etc.) are emerging porous materials. Their precisely defined structural units, uniform porosity, and good stability give POPs great potential as a platform for custom ORR electrocatalyst support. In addition, the abundant nitrogen species in POPs provide ideal binding sites for chelating metal atoms. By modifying the nitrogen sites in the POPs framework with transition metals, well-defined TM-Nx sites can be constructed, resulting in MNC-like materials with clear structures, providing a feasible platform for exploring the relationship between catalyst activity and structure. Furthermore, due to the high stability of covalent bonds, POPs are suitable for catalysis in acidic and alkaline media, making them ideal materials for electrocatalytic reactions. The structural design of POPs is diverse, and materials with target structures can be designed. Therefore, using pyrolytic POPs materials not only allows for a clear analysis of the influence of active site configuration on oxygen reduction electrocatalysis, but also enables the regulation of the electron density of active sites coordinated by TM-Nx by changing the framework design. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a method for preparing a non-pyrolytic single-atom catalyst, which, based on framework regulation, improves the electrocatalytic oxygen reduction performance of the non-pyrolytic single-atom catalyst.

[0006] To achieve the above objectives, the present invention provides a method for preparing a non-pyrolytic single-atom catalyst, comprising the following steps:

[0007] S1. Preparation of POP: Monomer 1, monomer 2, monomer 3 and palladium catalyst were dissolved in a solvent, reacted under an inert atmosphere, and then saturated sodium carbonate solution was added. After the reaction was heated and stirred, the mixture was filtered, washed, and the red solid was collected and dried under vacuum to obtain POP. S2. Preparation of POP-TM: POP and transition metal salts were uniformly dispersed in a solvent, and the reaction was carried out in multiple cycles of freezing-vacuum-thawing, followed by heating, filtration, washing, and drying to obtain POP-TM containing TM-N2 precursor sites. S3. Preparation of POP-TM-phen(OH): The small molecule ligand is uniformly dispersed in a solvent, POP-TM solution is added, ultrasonic dispersion is performed, and the reaction is carried out in multiple cycles of freezing-vacuum-thawing and heating. After filtration, washing and drying, POP-TM-phen(OH) is obtained, which is a non-pyrolytic single-atom catalyst.

[0008] Preferably, the mass ratio of monomer 1, monomer 2, monomer 3 and palladium catalyst in step S1 is 1:0.5~2:2~4:0.25~0.6.

[0009] More preferably, monomer 1 is 5,5'-dibromo-2,2'-bipyridine, monomer 2 is 4,4-dibromobiphenyl, and palladium catalyst is tetrakis(triphenylphosphine)palladium.

[0010] More preferably, the monomer 3 is any one of 4-(tetramethyl-1,3,2-dioxoboran-2-yl)-N,N-bis-[4-(tetramethyl-1,3,2-dioxoboran-2-yl)phenylaniline, 1,3,5-tris(4-phenylboronic acid pinacol ester)benzene, and 2,4,6-tris(4-(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)phenyl)-1,3,5-triazine.

[0011] Preferably, the volume ratio of the solvent to the saturated sodium carbonate solution in step S1 is 1:0.25~0.5.

[0012] More preferably, the solvent is N',N'-dimethylformamide (DMF).

[0013] Preferably, the heating and stirring reaction conditions in step S1 are 60-100°C for 24-48 hours.

[0014] Preferably, the molar ratio of POP to metal ions in the transition metal salt in step S2 is 1:1 to 1.5.

[0015] More preferably, the transition metal salt includes any one of transition metal hydrochloride, transition metal sulfate, transition metal nitrate, transition metal acetate, and transition metal sulfonate; the transition metal is one or more of Fe, Co, Ni, Cu, or Zn.

[0016] Preferably, the solvent in step S2 is any one of DMF, DMSO, and NMP; the heating reaction conditions are 50~80℃ for 4~8 h.

[0017] Preferably, the dispersion of POP in the solvent in step S2 is 1~3 mg·L. -1 .

[0018] Preferably, the molar ratio of the bipyridine unit to the small molecule ligand in the POP-TM described in step S3 is 1:1 to 1.5.

[0019] More preferably, the small molecule ligand is 4,7-dihydroxy-1,10-phenanthroline.

[0020] Preferably, the solvent in step S3 is N',N'-dimethylformamide (DMF); the dispersibility of POP-TM in the solvent is 2~4 mg·L⁻¹. -1 The small molecule ligands have a dispersion of 1–2 mg·L⁻¹ in the solvent. -1 .

[0021] Preferably, the heating reaction conditions described in step S3 are 50-80°C for 4-8 hours.

[0022] The present invention also provides a method for preparing a non-pyrolytic single-atom catalyst, and the application of the prepared non-pyrolytic single-atom catalyst in fuel cells and / or rechargeable metal-based batteries.

[0023] The beneficial effects of this invention are as follows: Based on framework regulation, the POP framework synthesized using a three-monomer system, after forming the Co-N2N2 configuration, not only has a half-wave potential of 0.830 V vs. RHE, but also has excellent 4-electron selectivity, with selectivity exceeding 90% in the potential range of 0.3-0.7 V vs. RHE. Attached Figure Description

[0024] Figure 1 This is a flowchart of the preparation process for Example 1.

[0025] Figure 2 (a) ORR polarization curve of POP measured in 0.1M KOH solution in Example 1; (b) corresponding H2O2 yield and number of transferred electrons.

[0026] Figure 3 (a) ORR polarization curve of POP-TM in 0.1M KOH solution in Example 1; (b) corresponding H2O2 yield and number of transferred electrons.

[0027] Figure 4 (a) ORR polarization curve of POP-TM-phen(OH) in 0.1M KOH solution in Example 1; (b) corresponding H2O2 yield and number of transferred electrons.

[0028] Figure 5 The image shows the XRD pattern of POP-TM-phen(OH) in Example 1.

[0029] Figure 6 The image shown is a SEM-EDS image of POP-TM-phen(OH) in Example 1.

[0030] Figure 7 The image shows the FT-IR spectrum of POP-TM-phen(OH) in Example 1.

[0031] Figure 8The XPS spectra of POP-TM in Example 1 are: (a) C 1s; (b) N 1s; (c) O 1s; (d) Co 2p.

[0032] Figure 9 The XPS spectra of POP-TM-phen(OH) in Example 1 are: (a) C 1s; (b) N 1s; (c) O 1s; (d) Co2p.

[0033] Figure 10 This is a flowchart of the POP preparation process in Example 2.

[0034] Figure 11 (a) ORR polarization curve of POP measured in 0.1 M KOH solution in Example 2; (b) corresponding H2O2 yield and number of transferred electrons.

[0035] Figure 12 (a) ORR polarization curves of POP-TM measured in 0.1 M KOH solution in Example 2; (b) corresponding H2O2 yield and number of transferred electrons.

[0036] Figure 13 (a) ORR polarization curve of POP-TM-phen(OH) in 0.1 M KOH solution in Example 2; (b) corresponding H2O2 yield and number of transferred electrons.

[0037] Figure 14 The ORR polarization curve of POP-TM-phen(OH) in 0.1M KOH solution is shown in Example 3.

[0038] Figure 15 The ORR polarization curve of POP-TM-phen(OH) in 0.1M KOH solution is shown in Example 4.

[0039] Figure 16 (a) ORR polarization curve of POP in 0.1M KOH solution in Comparative Example 1; (b) corresponding H2O2 yield and number of transferred electrons.

[0040] Figure 17 (a) ORR polarization curves of POP-TM measured in 0.1M KOH solution in Comparative Example 1; (b) corresponding H2O2 yield and number of transferred electrons.

[0041] Figure 18 (a) ORR polarization curve of POP-TM-phen(OH) in 0.1M KOH solution in Comparative Example 1; (b) corresponding H2O2 yield and number of transferred electrons. Detailed Implementation

[0042] The technical solution of the present invention will be further explained and described below with reference to the accompanying drawings and specific embodiments. It is worth noting that the following embodiments are only preferred embodiments of the present invention and should not be construed as limiting the present invention. The scope of protection of the present invention should be determined by the contents of the claims. Modifications and substitutions made by those skilled in the art to the technical solution of the present invention without creative effort all fall within the scope of protection of the present invention.

[0043] In the following embodiments: ORR testing method: 3 mg of catalyst, 1.5 mg of carbon black, and 1.5 mg of carbon nanotubes were ground and then dispersed in 760 μL of ethanol, 200 μL of water, and 40 μL of 5 wt% Nafion to obtain a slurry. The slurry was thoroughly mixed in an ultrasonicator for 60 min, and then the catalyst slurry was loaded onto a rotating ring-disk electrode (RRDE, with an area of ​​0.1256 cm²). -2 The catalyst loading was consistently maintained at 0.8 mg·cm⁻¹. -2 The test was conducted using a three-electrode system consisting of a reference electrode (mercuric oxide), a counter electrode (carbon rod), and a working electrode in an oxygen-saturated 0.1 M KOH solution. Formula for calculating hydrogen oxide yield: , Formula for calculating the number of transferred electrons: , Where N is the collection efficiency of the ring electrode, and its value is 0.4.

[0044] SEM-EDS images were acquired using a TESCAN MIRA LMS apparent scanning electron microscope with an accelerating voltage of 3 kV. Fourier transform infrared (FT-IR) results were obtained using a Thermo Scientific Nicolet iS20 instrument. Powder X-ray diffraction (PXRD) results were obtained using a Ultima IV instrument. X-ray photoelectron spectroscopy (XPS) analysis was performed using a Thermo Scientific K-Alpha instrument at 72 W and 100 eV with single-chromium Al Kα radiation.

[0045] Example 1 S1: 5,5'-dibromo-2,2'-bipyridine (100 mg), 4,4-dibromobiphenyl (50 mg), 4-(tetramethyl-1,3,2-dioxoron-2-yl)-N,N-bis-[4-(tetramethyl-1,3,2-dioxoron-2-yl)phenylaniline (200 mg), and the catalyst tetra(triphenylphosphine)palladium (30 mg) were dissolved in N',N'-dimethylformamide solvent (DMF) (15 mL), and after being placed under argon atmosphere for 15 min, saturated Na2CO3 solution (7 mL) was added. Finally, the mixture was heated to 60 °C in an oil bath and stirred for 48 h. After the reaction was completed, the mixture was washed three times each with deionized water and ethanol, and once with tetrahydrofuran. The yellow solid was collected and dried under vacuum for 24 h to obtain POP. S2: Take POP (20 mg) and Co(OAc)2 4H2O (20 mg) was added to the ampoule and ultrasonically dispersed for 5 min. The ampoule was then frozen-vacuumed and thawed three times. After the last vacuuming, the ampoule was flame-sealed and then thawed. The sealed ampoule was then shaken in a constant temperature shaker at 60 °C for 6 h. The product was washed several times with N',N' dimethylformamide, the solid was collected, and then vacuum dried for 24 h to obtain the target catalyst POP-TM. S3: Disperse the POP-TM obtained in step S2 in N',N'-dimethylformamide (9 mL) to obtain a POP-TM solution; then add 4,7-dihydroxy-1,10-phenanthroline (10 mg), sonicate for 5 min, freeze-vacuum-thaw the ampoule, repeat this operation three times, after the last vacuuming, flame seal the ampoule and then thaw; shake the sealed ampoule in a constant temperature shaker at 60℃ for 6 h, wash the obtained product several times with N',N'-dimethylformamide, collect the solid, and then vacuum dry it for 24 h to obtain the target catalyst POP-TM-phen(OH) ( Figure 1 ).

[0046] Results Detection: The ORR catalytic performance of the POP prepared in step S1 was measured in an alkaline electrolyte (0.1 M KOH aqueous solution), specifically its half-wave potential (E) in the 0.1 M KOH electrolyte. 1 / 2 The potential value is 0.675 V. Within the potential range of 0.3-0.7 V, the number of electrons transferred is greater than 3.4, and the yield of H₂O₂ is less than 30%. Figure 2 During detection, POP was prepared as a film electrode and loaded onto a rotating ring-disk electrode RRDE, with the catalyst loading consistently maintained at 0.8 mg / cm³. -2 It is not dispersed in the solution.

[0047] The ORR catalytic performance of POP-TM prepared in step S2 was measured in an alkaline electrolyte (0.1 M KOH aqueous solution), specifically its half-wave potential (E) in the 0.1 M KOH electrolyte. 1 / 2 The potential value is 0.770 V. Within the potential range of 0.3-0.7 V, the number of electrons transferred is greater than 3.4, and the yield of H₂O₂ is less than 30%. Figure 3 ).

[0048] The ORR catalytic performance of POP-TM-phen(OH) prepared in step S3 was measured in an alkaline electrolyte (0.1 M KOH aqueous solution), and its half-wave potential (E) in the 0.1 M KOH electrolyte was also measured. 1 / 2 The potential value is 0.830 V. Within the potential range of 0.3-0.7 V, the number of electrons transferred is greater than 3.7, and the yield of H₂O₂ is less than 20%. Figure 4 ).

[0049] X-ray diffraction of POP-TM-phen(OH) yielded the following results: Figure 5 As shown in the XRD pattern, it has an amorphous structure, indicating that POP-TM-phen(OH) can be successfully prepared using the above method. The SEM-EDS image shows a layered structure, with C, N, O, and Co elements uniformly distributed on the material. Figure 6 ); FT-IR spectra are shown at 1490–1510 cm⁻¹ -1 and 1320 cm -1 The characteristic vibrations observed at [location] indicate the successful formation of the POP framework, and that POP-TM-phen(OH) and POP-TM essentially maintain the structure of POP; furthermore, POP-TM and POP-TM-phen(OH) exhibit vibrations at 1030–1050 cm⁻¹. -1 The presence of Co-N characteristic vibrational peaks nearby confirms the successful coordination of Co ions with nitrogen. Figure 7 ).

[0050] XPS spectra of POP-TM and POP-TM-phen(OH) showed the presence of C, N, O, and Co elements, further confirming the successful preparation of both. Figure 8-9 C1s XPS spectra of POP-TM and POP-TM-phen(OH) Figure 8From the perspectives of (b and 9b), the peaks at 284.8, 286.0, and 288.6 eV are attributed to CC / C=C, CN / C=N, and C=O, respectively, while the peaks at 398.8 and 400.3 eV correspond to -C=N- and -CN- in the POP framework, respectively. The peak at 399.4 eV in POP-TM and POP-TM-phen(OH) corresponds to Co-N, indicating the successful chelation of the Co ion with the nitrogen of the bipyridine group in the POP-Ⅳ framework. The Co 2p XPS spectra of POP-TM and POP-TM-phen(OH) (…) Figure 8 d and Figure 9 As shown in d), the peaks of POP-TM and POP-TM-phen(OH) at 780.1, 781.0, and 785.4 eV are satellite peaks of Co-O, Co-N, and Co, respectively, with the Co-O originating from cobalt acetate. The area ratio of the Co-O and Co-N peaks in POP-TM is almost 1:1, indicating the presence of equal amounts of Co-N and Co-O bonds in POP-TM. The peaks of POP-TM-phen(OH) at 780.1, 781.0, and 783.4 eV correspond to satellite peaks of Co-O, Co-N, and Co, respectively. Unlike POP-TM, the area of ​​the Co-O peak in POP-TM-phen(OH) is significantly smaller than that of the Co-N peak. This is because phen(OH) has been modified to replace the acetate group, forming Co-N2N2 sites around the Co atom.

[0051] Example 2 S1: 5,5'-dibromo-2,2'-bipyridine (50 mg), 4,4-dibromobiphenyl (100 mg), 4-(tetramethyl-1,3,2-dioxoron-2-yl)-N,N-bis-[4-(tetramethyl-1,3,2-dioxoron-2-yl)phenylaniline (200 mg), and the catalyst tetra(triphenylphosphine)palladium (30 mg) were dissolved in N',N'-dimethylformamide solvent (DMF) (15 mL). The mixture was placed under argon atmosphere for 15 min, and then saturated Na2CO3 solution (7 mL) was added. Finally, the mixture was heated in an oil bath to 60 °C and stirred for 48 h. After the reaction was complete, the mixture was washed three times each with deionized water and ethanol, and once with tetrahydrofuran. The yellow solid was collected and dried under vacuum for 24 h to obtain POP (…). Figure 10 ); S2: POP (20 mg) and Co(OAc)2 4H2O (20 mg) was added to the ampoule and ultrasonically dispersed for 5 min. The ampoule was then frozen-vacuumed and thawed three times. After the last vacuuming, the ampoule was flame-sealed and then thawed. The sealed ampoule was then shaken in a constant temperature shaker at 60 °C for 6 h. The product was washed several times with N',N' dimethylformamide, the solid was collected, and then vacuum dried for 24 h to obtain the target catalyst POP-TM. S3: Disperse the POP-TM obtained in step S2 in N',N'-dimethylformamide (9 mL) to obtain a POP-TM solution; then add 4,7-dihydroxy-1,10-phenanthroline (10 mg), sonicate for 5 min, freeze-vacuum-thaw the ampoule, repeat this operation three times, after the last vacuuming, flame seal the ampoule and then thaw; shake the sealed ampoule in a constant temperature shaker at 60℃ for 6 h, wash the obtained product several times with N',N'-dimethylformamide, collect the solid, and then vacuum dry it for 24 h to obtain the target catalyst POP-TM-phen(OH).

[0052] Results Detection: The ORR catalytic performance of the POP prepared in step S1 was measured in an alkaline electrolyte (0.1 M KOH aqueous solution), specifically its half-wave potential (E) in the 0.1 M KOH electrolyte. 1 / 2 The potential value is 0.661 V. Within the potential range of 0.3-0.7 V, the number of electrons transferred is greater than 3.1, and the yield of H₂O₂ is less than 50%. Figure 11 ).

[0053] The ORR catalytic performance of POP-TM prepared in step S2 was measured in an alkaline electrolyte (0.1 M KOH aqueous solution), specifically its half-wave potential (E) in the 0.1 M KOH electrolyte. 1 / 2 The potential value is 0.753 V. Within the potential range of 0.3-0.7 V, the number of electrons transferred is greater than 3.0, and the yield of H₂O₂ is less than 50%. Figure 12 ).

[0054] The ORR catalytic performance of POP-TM-phen(OH) prepared in step S3 was measured in an alkaline electrolyte (0.1 M KOH aqueous solution), and its half-wave potential (E) in the 0.1 M KOH electrolyte was also measured. 1 / 2 The potential value is 0.805 V. Within the potential range of 0.3-0.7 V, the number of electrons transferred is greater than 3.6, and the yield of H₂O₂ is less than 20%. Figure 13 ).

[0055] Example 3 S1: 5,5'-dibromo-2,2'-bipyridine (100 mg), 4,4-dibromobiphenyl (50 mg), 4-(tetramethyl-1,3,2-dioxoron-2-yl)-N,N-bis-[4-(tetramethyl-1,3,2-dioxoron-2-yl)phenylaniline (200 mg), and the catalyst tetra(triphenylphosphine)palladium (30 mg) were dissolved in N',N'-dimethylformamide solvent (DMF) (15 mL), and after being placed under argon atmosphere for 15 min, saturated Na2CO3 solution (7 mL) was added. Finally, the mixture was heated to 60 °C in an oil bath and stirred for 48 h. After the reaction was completed, the mixture was washed three times each with deionized water and ethanol, and once with tetrahydrofuran. The yellow solid was collected and dried under vacuum for 24 h to obtain POP. S2: Take POP (20 mg) and Ni(OAc)2 4H2O (20 mg) was added to the ampoule and ultrasonically dispersed for 5 min. The ampoule was then frozen-vacuumed and thawed three times. After the last vacuuming, the ampoule was flame-sealed and then thawed. The sealed ampoule was then shaken in a constant temperature shaker at 60 °C for 6 h. The product was washed several times with N',N' dimethylformamide, the solid was collected, and then vacuum dried for 24 h to obtain the target catalyst POP-Ni. S3: The POP-Ni obtained in step S2 was dispersed in N',N'-dimethylformamide (9 mL) to obtain a POP-Ni solution; then 4,7-dihydroxy-1,10-phenanthroline (13.4 mg) was added, and the mixture was ultrasonically dispersed for 5 min. The ampoule was subjected to a freeze-vacuum-thaw cycle, which was repeated three times. After the last vacuum cycle, the ampoule was flame-sealed and then thawed. The sealed ampoule was shaken in a constant temperature shaker at 60 °C for 6 h. The product was washed multiple times with N',N'-dimethylformamide, and the solid was collected. After vacuum drying for 24 h, the target catalyst POP-Ni-phen(OH) was obtained.

[0056] Results Detection: The ORR catalytic performance of POP-Ni-phen(OH) in alkaline electrolyte (0.1M KOH aqueous solution) was measured, and its half-wave potential (E) in 0.1 M KOH electrolyte was determined. 1 / 2 The value is 0.76 V, such as Figure 14 .

[0057] Example 4 S1: 5,5'-dibromo-2,2'-bipyridine (100 mg), 4,4-dibromobiphenyl (50 mg), 4-(tetramethyl-1,3,2-dioxoron-2-yl)-N,N-bis-[4-(tetramethyl-1,3,2-dioxoron-2-yl)phenylaniline (200 mg), and the catalyst tetra(triphenylphosphine)palladium (30 mg) were dissolved in N',N'-dimethylformamide solvent (DMF) (15 mL), and after being placed under argon atmosphere for 15 min, saturated Na2CO3 solution (7 mL) was added. Finally, the mixture was heated to 60 °C in an oil bath and stirred for 48 h. After the reaction was completed, the mixture was washed three times each with deionized water and ethanol, and once with tetrahydrofuran. The yellow solid was collected and dried under vacuum for 24 h to obtain POP. S2: Add POP (20 mg) and zinc perchlorate hexahydrate (20 mg) to an ampoule, sonicate for 5 min, freeze-vacuum-thaw the ampoule, repeat this operation three times, after the last vacuuming, seal the ampoule with a flame and then thaw; shake the sealed ampoule in a constant temperature shaker at 60℃ for 6 h, wash the obtained product several times with N',N' dimethylformamide, collect the solid, and then vacuum dry it for 24 h to obtain the target catalyst POP-Zn; S3: The POP-Zn obtained in step S2 was dispersed in N',N'-dimethylformamide (9 mL) to obtain a POP-Ni solution; then 4,7-dihydroxy-1,10-phenanthroline (13.4 mg) was added, and the mixture was ultrasonically dispersed for 5 min. The ampoule was subjected to a freeze-vacuum-thaw cycle, which was repeated three times. After the last vacuum cycle, the ampoule was flame-sealed and then thawed. The sealed ampoule was shaken in a constant temperature shaker at 60 °C for 6 h. The product was washed multiple times with N',N'-dimethylformamide, and the solid was collected. After vacuum drying for 24 h, the target catalyst POP-Zn-phen(OH) was obtained.

[0058] Results Detection: The ORR catalytic performance of POP-Zn-phen(OH) in alkaline electrolyte (0.1M KOH aqueous solution) was measured, and its half-wave potential (E) in 0.1 M KOH electrolyte was determined. 1 / 2 The value is 0.74 V, such as Figure 15 .

[0059] Comparative Example 1 S1: 5,5'-dibromo-2,2'-bipyridine (150 mg), 4-(tetramethyl-1,3,2-dioxoron-2-yl)-N,N-bis-[4-(tetramethyl-1,3,2-dioxoron-2-yl)phenylaniline (200 mg), and the catalyst tetra(triphenylphosphine)palladium (30 mg) were dissolved in N',N'-dimethylformamide solvent (DMF) (15 mL), and after being placed under argon atmosphere for 15 min, saturated Na2CO3 solution (7 mL) was added. Finally, the mixture was heated in an oil bath to 60 °C and stirred for 48 h. After the reaction was completed, the mixture was washed three times each with deionized water and ethanol, and once with tetrahydrofuran. The red solid was collected and dried under vacuum for 24 h to obtain the final POP. S2: POP (20 mg) and Co(OAc)2 4H2O (20 mg) was added to the ampoule and ultrasonically dispersed for 5 min. The ampoule was then frozen-vacuumed and thawed three times. After the last vacuuming, the ampoule was flame-sealed and then thawed. The sealed ampoule was then shaken in a constant temperature shaker at 60 °C for 6 h. The product was washed several times with N',N' dimethylformamide, the solid was collected, and then vacuum dried for 24 h to obtain the target catalyst POP-TM. S3: Disperse the POP-TM obtained in step S2 in N',N'-dimethylformamide (9 mL) to obtain a POP-TM solution; then add 4,7-dihydroxy-1,10-phenanthroline (13.4 mg), sonicate for 5 min, freeze-vacuum-thaw the ampoule, repeat this operation three times, after the last vacuuming, flame seal the ampoule and then thaw; shake the sealed ampoule in a constant temperature shaker at 60℃ for 6 h, wash the obtained product several times with N',N'-dimethylformamide, collect the solid, and then vacuum dry it for 24 h to obtain the target catalyst POP-TM-phen(OH).

[0060] The results showed that the ORR catalytic performance of the POP prepared in step S1 in alkaline electrolyte was as follows: its half-wave potential (E) in 0.1 MKOH electrolyte was [not specified]. 1 / 2 The potential value is 0.670 V. Within the potential range of 0.3-0.7 V, the number of electrons transferred is greater than 3.3, and the yield of H₂O₂ is less than 40%. Figure 16 ).

[0061] The ORR catalytic performance of POP-TM prepared in step S2 in alkaline electrolyte was measured, specifically its half-wave potential (E) in 0.1 M KOH electrolyte. 1 / 2 The potential value is 0.713 V. Within the potential range of 0.3-0.7 V, the number of electrons transferred is greater than 3.0, and the yield of H₂O₂ is less than 50%. Figure 17 ).

[0062] The ORR catalytic performance of POP-TM prepared in step S3 in alkaline electrolyte was measured, specifically its half-wave potential (E) in 0.1 M KOH electrolyte. 1 / 2 The potential value is 0.825 V. Within the potential range of 0.3-0.7 V, the number of electrons transferred is greater than 3.6, and the yield of H₂O₂ is less than 20%. Figure 18 ).

Claims

1. A method for preparing a non-pyrolytic single-atom catalyst, characterized in that: Includes the following steps: S1. Preparation of POP: Monomer 1, monomer 2, monomer 3 and palladium catalyst were dissolved in a solvent, reacted under an inert atmosphere, and then saturated sodium carbonate solution was added. After the reaction was heated and stirred, the mixture was filtered, washed, and the red solid was collected and dried under vacuum to obtain POP. S2. Preparation of POP-TM: POP and transition metal salts were uniformly dispersed in a solvent, and the reaction was carried out in multiple cycles of freezing-vacuum-thawing, followed by heating, filtration, washing, and drying to obtain POP-TM containing TM-N2 precursor sites. S3. Preparation of POP-TM-phen(OH): The small molecule ligand is uniformly dispersed in a solvent, POP-TM solution is added, ultrasonic dispersion is performed, and the reaction is carried out in multiple cycles of freezing-vacuum-thawing and heating. After filtration, washing and drying, POP-TM-phen(OH) is obtained, which is a non-pyrolytic single-atom catalyst.

2. The method for preparing a non-pyrolytic single-atom catalyst according to claim 1, characterized in that: The mass ratio of monomer 1, monomer 2, monomer 3 and palladium catalyst in step S1 is 1:0.5~2:2~4:0.25~0.

6.

3. The method for preparing a non-pyrolytic single-atom catalyst according to claim 2, characterized in that: The monomer 1 is 5,5'-dibromo-2,2'-bipyridine, the monomer 2 is 4,4-dibromobiphenyl, and the palladium catalyst is tetrakis(triphenylphosphine)palladium.

4. The method for preparing a non-pyrolytic single-atom catalyst according to claim 2, characterized in that: The monomer 3 is any one of 4-(tetramethyl-1,3,2-dioxoboran-2-yl)-N,N-bis-[4-(tetramethyl-1,3,2-dioxoboran-2-yl)phenylaniline, 1,3,5-tris(4-phenylboronic acid pinacol ester)benzene, and 2,4,6-tris(4-(4,4,5,5-tetramethyl-1,3,2-dioxoborane-2-yl)phenyl)-1,3,5-triazine.

5. The method for preparing a non-pyrolytic single-atom catalyst according to claim 1, characterized in that: The volume ratio of the solvent to the saturated sodium carbonate solution in step S1 is 1:0.25~0.

5.

6. The method for preparing a non-pyrolytic single-atom catalyst according to claim 1, characterized in that: The molar ratio of POP to metal ions in the transition metal salt mentioned in step S2 is 1:1 to 1.

5.

7. The method for preparing a non-pyrolytic single-atom catalyst according to claim 6, characterized in that: The transition metal salt includes any one of transition metal hydrochloride, transition metal sulfate, transition metal nitrate, transition metal acetate, and transition metal sulfonate; the transition metal is one or more of Fe, Co, Ni, Cu, or Zn.

8. The method for preparing a non-pyrolytic single-atom catalyst according to claim 1, characterized in that: In step S3, the molar ratio of bipyridine units to small molecule ligands in POP-TM is 1:0.75~1.

5.

9. The method for preparing a non-pyrolytic single-atom catalyst according to claim 8, characterized in that: The small molecule ligand is 4,7-dihydroxy-1,10-phenanthroline.

10. The application of a non-pyrolytic single-atom catalyst prepared by the method of any one of claims 1-9 in fuel cells and / or rechargeable metal-based batteries.

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