Monatomic spin catalyst as well as preparation method and application thereof

Abstract

The invention belongs to the technical field of catalysts, and discloses a monatomic spin catalyst as well as a preparation method and application thereof. The monatomic spin catalyst comprises a magnetic element-NC substrate and a heavy metal loaded on the magnetic element-NC substrate. According to the monatomic spin catalyst, strong spin orbit coupling (SOC) heavy metal (such as Ta) is introduced to form an indirect bonding structure (Fe-N-Ta) with Fe monatomic, the spin state and spin polarization of Fe are cooperatively regulated and controlled, the energy barrier of an oxygen intermediate is remarkably reduced, and the monatomic spin catalyst has a good oxygen evolution reaction catalysis effect.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, and specifically relates to a single-atom spin catalyst, its preparation method, and its application. Background Technology

[0002] The increasingly severe energy and environmental problems make the development and utilization of new clean energy sources (such as hydrogen and solar energy) an urgent priority. In the process of implementing hydrogen production infrastructure, continuous optimization of water electrolyzer efficiency is crucial, with the performance of the anolyte oxygen evolution reaction catalyst being a key factor affecting the efficiency of the water electrolyzer.

[0003] Currently, the design of catalysts for the anodic oxygen evolution reaction (OER) is mainly based on the Sabatier theory (volcano curve theory). However, the optimal catalyst predicted by this theory has reached a performance bottleneck. Since the water splitting process involves the spin properties of electrons, controlling the electron spin structure of the catalyst holds promise for breaking through this bottleneck and achieving further performance breakthroughs. However, current methods for controlling electron spin are limited in effectiveness and cannot effectively regulate the catalyst's spin structure. Furthermore, existing technologies such as magnetic field modulation or crystal field modulation can only adjust the spin state or spin polarization individually, with limited performance improvements (<5 times), making it difficult to meet the demands of industrial applications.

[0004] Therefore, there is an urgent need for catalysts with better performance. Summary of the Invention

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a single-atom spin catalyst, its preparation method, and its application. The single-atom spin catalyst of this invention introduces a strongly spin-orbit coupled (SOC) heavy metal (HM) (such as Hf, Ta, W, Re, Os, Ir, Pt, Au, etc., and other transition metals with atomic numbers greater than TM (TM refers to Fe, Co, or Ni magnetic elements)) to form an indirect bonding structure (TM-N-HM) with a single TM atom, synergistically regulating the spin state and spin polarization of Fe, significantly reducing the energy barrier of the oxygen intermediate. For example, the prepared Ta5@Fe-NC catalyst achieves a 115-fold increase in the TOF (transition frequency) of the OER (oxygen evolution reaction) (compared to Fe-NC), an ORR half-wave potential of 0.94V (superior to Pt / C catalysts), and possesses high-temperature stability (magnetic transition temperature T). b >400K).

[0006] A first aspect of the present invention provides a single-atom spin catalyst.

[0007] A single-atom spin catalyst comprising a magnetic element-NC substrate and a heavy metal supported on the magnetic element-NC substrate.

[0008] Preferably, the magnetic element-NC substrate refers to a single atom of Fe, Co, or Ni dispersed in the form of magnetic element-N4 on an N-doped carbon substrate.

[0009] Preferably, the heavy metal includes at least one transition metal such as Hf, Ta, W, Re, Os, Ir, Pt, Au, and other elements with atomic numbers greater than those of magnetic elements.

[0010] Preferably, the heavy metal includes Hf, Ta, W, Re, Os, Ir, Pt, Au, and at least one other transition metal with an atomic number greater than that of the magnetic element, and has different microscales, including single atoms, clusters, or particles.

[0011] Preferably, the heavy metal includes at least one transition metal such as Hf, Ta, W, Re, Os, Ir, Pt, Au, and other elements with atomic numbers greater than those of magnetic elements.

[0012] Preferably, the heavy metal clusters are indirectly bonded via Fe-N-Ta.

[0013] Preferably, the diameter of the heavy metal cluster is 1-5 nm.

[0014] More preferably, the heavy metal includes Ta.

[0015] Preferably, the heavy metal includes Ta clusters, single-atom Ta, or particulate Ta, and more preferably Ta clusters.

[0016] Preferably, the heavy metal clusters are indirectly bonded through a "magnetic atom-N-heavy metal atom" bond.

[0017] Preferably, the Ta clusters are indirectly bonded via Fe-N-Ta.

[0018] Preferably, the diameter of the Ta cluster is 1-5 nm, more preferably 1-3 nm.

[0019] Preferably, the single-atom spin catalyst does not contain magnetic metal-magnetic metal bonds.

[0020] Preferably, the single-atom spin catalyst does not contain Fe-Fe bonds.

[0021] A second aspect of the present invention provides a method for preparing a single-atom spin catalyst.

[0022] A method for preparing a single-atom spin catalyst includes the following steps:

[0023] (1) Preparation of carbon substrate: Zinc acetate was dissolved to obtain solution A, 2,5-dihydroxyterephthalic acid was dissolved to obtain solution B, and salicylic acid was dissolved to obtain solution C. Then, solutions A, B and C were mixed and reacted to obtain a precipitate. The precipitate was subjected to hydrothermal reaction and dried to obtain a metal-organic framework (MOF) precursor. Then, it was pyrolyzed under a protective gas atmosphere to obtain a carbon substrate.

[0024] (2) Preparation of magnetic element-NC substrate: Magnetic element salt and 1,10-phenanthroline are dissolved in a solvent to obtain solution D. Then the carbon substrate is mixed with solution D, ultrasonically treated, and dried to obtain a composite. Then it is heat-treated and acid-washed to obtain magnetic element-NC substrate.

[0025] (3) Loading heavy metals: The magnetic element-NC substrate is dispersed in a solvent, then a heavy metal salt solution is added and dried to obtain a magnetic element-NC precursor modified with heavy metal salt. Then, it is annealed to obtain the single-atom spin catalyst.

[0026] Preferably, the solvent is selected from at least one of dimethylformamide (DMF), deionized water, methanol, and ethanol.

[0027] Preferably, in step (1), the hydrothermal reaction temperature is 100-120°C and the hydrothermal reaction time is 24-36 hours.

[0028] Preferably, in step (1), the pyrolysis temperature is 800-1000℃ and the pyrolysis time is 2-4 hours.

[0029] Preferably, in step (1), the mass ratio of zinc acetate, 2,5-dihydroxyterephthalic acid and salicylic acid is 5.5:(1.0-5.0):(0.5-3), and more preferably 5.5:2.0:1.1.

[0030] Preferably, in step (2), the magnetic element salt includes ferrous sulfate.

[0031] Preferably, in step (2), the mass ratio of the magnetic element salt, 1,10-phenanthroline, and carbon substrate is 20:(20-50):(90-110), and more preferably 20:40:100.

[0032] Preferably, in step (2), the heat treatment process is a two-stage heat treatment under an inert gas atmosphere, first heating at 130-150°C for 1-2 hours, and then raising the temperature to 700-800°C and holding for 2-3 hours.

[0033] Preferably, in step (3), the heavy metal salt solution includes an organic solution or an aqueous solution of heavy metal chloride.

[0034] Preferably, the heavy metal chloride is selected from at least one of HfCl4, TaCl5, WCl6, ReCl5, OsCl3, IrCl3, and H2[PtCl6].

[0035] Preferably, the concentration of the n-butanol solution of TaCl5, one of the heavy metal salt solutions, is 180-220 g / L.

[0036] Preferably, in step (3), the ratio of the amount of magnetic element-NC substrate to the n-butanol solution of TaCl5 is 50 mg:(0.5-30) μL.

[0037] Preferably, in step (3), the heavy metal salt solution is a TaCl5 n-butanol solution.

[0038] Preferably, in step (3), the concentration of the n-butanol solution of TaCl5 is 190-200 g / L.

[0039] Preferably, in step (3), the ratio of the amount of magnetic element-NC substrate to the n-butanol solution of TaCl5 is 50 mg:(3-20) μL, more preferably 50 mg:(5-10) μL.

[0040] Preferably, in step (3), the annealing temperature is 800-900℃ and the annealing time is 20-30 minutes.

[0041] Preferably, in step (3), after the annealing is completed, ammonia gas is introduced for 20-40 minutes, and then inert gas is introduced until it is cooled to room temperature.

[0042] A third aspect of the present invention provides an application of a single-atom spin catalyst.

[0043] Applications of the single-atom spin catalysts prepared by the above method in the field of catalysis.

[0044] Preferably, the catalytic field includes the electrocatalytic field.

[0045] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0046] (1) The single-atom spin catalyst of the present invention introduces a strong spin-orbit coupling (SOC) heavy metal (such as Ta) to form an indirect bonding structure (Fe-N-Ta) with Fe single atoms, which synergistically regulates the spin state and spin polarization of Fe, significantly reduces the energy barrier of oxygen intermediates, and has a good catalytic effect on oxygen evolution reaction.

[0047] The single-atom spin catalyst described in this invention synergistically regulates the spin state (increased spin state) and polarizability (>30%) of Fe, significantly reducing the energy barrier of oxygen intermediates. The Ta5@Fe-NC catalyst achieves a 115-fold increase in TOF for OER (compared to Fe-NC), a half-wave potential of 0.94V for ORR (superior to Pt / C), and exhibits high-temperature stability (T... b >400K).

[0048] (2) The preparation method described in this invention employs specific steps to produce the above-mentioned single-atom spin catalyst with good catalytic performance. Attached Figure Description

[0049] Figure 1 The image shows the microstructure of the single-atom spin catalyst prepared in Example 1.

[0050] Figure 2 Structural characterization of the single-atom spin catalyst prepared in Example 1;

[0051] Figure 3 The results are the hysteresis loop test results of the single-atom spin catalysts prepared in Examples 1-3;

[0052] Figure 4 Temperature-dependent magnetic susceptibility curves for the single-atom spin catalysts prepared in Examples 1-3 and the catalyst prepared in Comparative Example 1;

[0053] Figure 5 The OER performance test results are for the single-atom spin catalysts prepared in Examples 1-3 and the catalysts prepared in Comparative Examples 1-2.

[0054] Figure 6 The ORR performance test results are for the single-atom spin catalysts prepared in Examples 1-3;

[0055] Figure 7 The results show a comparison of the half-wave potential performance of ORR between the single-atom spin catalyst prepared in Example 1 and existing catalysts. Detailed Implementation

[0056] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0057] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0058] Figure 1The microstructure diagrams show the single-atom Fe spin catalysts supported on single-atom Ta (prepared in Example 2), clustered Ta (prepared in Example 1), and particulate Ta (prepared in Example 3), respectively. (The diagrams are for each sample Ta.) 0.5 @Fe-NC, Ta5@Fe-NC, Ta 30 @Fe-NC; Figure 1 In this context, "Ta cluster" refers to Ta clusters, "Ta nanoparticle" represents Ta particles, and "TaSA" represents single-atom Ta.

[0059] Figure 2 Structural characterization of the single-atom spin catalyst prepared in Example 1; Figure 2 In this context, "Intensity" refers to the intensity of the iron foil, "Energy" refers to the energy, "Fe-foil" refers to iron foil, "FePc" refers to iron phthalocyanine, "Fe K-edge" refers to the K-edge absorption spectrum of Fe, "unchanged Fe valence state" means that the Fe valence state remains unchanged, "Fit" means fitting, and "Radial distance" refers to the radial distance. Figure 2 In graph b, the vertical axis represents the intensity of the absorption spectrum.

[0060] Figure 3 The results of hysteresis loop tests are for the single-atom spin catalysts prepared in Examples 1-3 and Comparative Example 1. Figure 3 In this context, "Magnetic field" refers to the magnetic field, and "Magnetic momentperFe" refers to the magnetic moment of Fe.

[0061] Figure 4 Temperature-dependent magnetic susceptibility curves for the single-atom spin catalysts prepared in Examples 1-3 and the catalyst prepared in Comparative Example 1; Figure 4 The vertical axis represents magnetic susceptibility, and the horizontal axis represents temperature.

[0062] Figure 5 The OER performance test results are for the single-atom spin catalysts prepared in Examples 1-3 and the catalysts prepared in Comparative Examples 1-2. Figure 5 In this context, "Potential" refers to electric potential, and "Current density" refers to current density.

[0063] Figure 6 ORR performance test results for the single-atom spin catalysts prepared in Examples 1-3 and the catalysts prepared in Comparative Examples 1-2; Figure 6 In this context, "Potential" refers to electric potential, and "Current density" refers to current density.

[0064] Figure 7 The results show a comparison of the half-wave potential performance of ORR between the single-atom spin catalyst prepared in Example 1 and existing catalysts. Figure 7 In this context, "This work" refers to the single-atom spin catalyst of Example 1, "Single / dual atom" refers to a single-atom or dual-atom catalyst, "Hydroxide / nitride" refers to a hydroxide or nitride, "NC-based" refers to an N-doped carbon substrate, "Commercial Pt / C" refers to a commercial Pt / C catalyst, and "(Non)noble catalyst" refers to a (non)noble metal catalyst.

[0065] Example 1

[0066] A method for preparing a single-atom spin catalyst includes the following steps:

[0067] Step 1: Preparation of carbon substrate

[0068] (1) Solution preparation:

[0069] Dissolve 5.5 g of anhydrous zinc acetate in 200 mL of dimethylformamide (DMF) to form solution A;

[0070] Dissolve 2.0 g of 2,5-dihydroxyterephthalic acid in 200 mL of DMF to form solution B;

[0071] Dissolve 1.1 g of salicylic acid in 50 mL of DMF to form solution C;

[0072] (2) Mixing and Reaction:

[0073] With vigorous stirring using a magnetic stirrer, solution A is slowly added dropwise to solution B over a period of 7 minutes, followed by stirring for another 3 minutes to ensure thorough mixing.

[0074] Add solution C to the mixture, stir ultrasonically for 30 minutes to promote uniform dispersion, and then let it stand for 12 hours to allow the reaction to proceed fully;

[0075] (3) Precipitation treatment and drying:

[0076] The precipitate generated by the reaction was collected by centrifugation and washed three times each with DMF and methanol to remove unreacted raw materials.

[0077] The washed precipitate was dispersed in 50 ml of methanol and transferred to a stainless steel high-pressure reactor, where it was hydrothermally reacted at 120 °C for 36 hours.

[0078] After the reaction was completed, the product was cooled to room temperature, washed again with methanol, and dried under vacuum at 150 °C for 24 hours to obtain the metal-organic framework (MOF) precursor.

[0079] (4) High-temperature pyrolysis:

[0080] The dried MOF precursor was placed in a tube furnace and pyrolyzed at 1000℃ for 4 hours under an argon (Ar) atmosphere. After natural cooling to room temperature, a carbon substrate with high specific surface area and porous structure was obtained.

[0081] Step 2: Fe-NC Synthesis

[0082] (1) Active site loading:

[0083] Dissolve 20 mg of ferrous sulfate (FeSO4) and 40 mg of 1,10-phenanthroline in 3 mL of deionized water to form solution D;

[0084] Add 100 mg of carbon substrate to solution D and sonicate for 3 hours to ensure that the carbon substrate is fully dispersed and coordinated with iron ions;

[0085] The mixture was then stirred continuously at room temperature for 12 hours to obtain a mixture in which iron single atoms were anchored to the nitrogen sites of the carbon substrate through coordination.

[0086] (2) Freeze-drying and heat treatment:

[0087] The mixture was freeze-dried to remove the solvent, yielding a dried complex;

[0088] The dried composite was subjected to a two-stage heat treatment under an argon atmosphere: first, it was heated at 150°C for 1 hour to stabilize the structure, and then the temperature was raised to 800°C and held for 3 hours to promote the formation of Fe-N4 active centers by Fe single atoms.

[0089] (3) Acid washing and purification:

[0090] The heat-treated sample was immersed in a 0.5M nitrogen-saturated sulfuric acid solution and stirred for 6 hours to remove residual metal particles.

[0091] The purified Fe-NC was collected by centrifugation and then vacuum dried for later use.

[0092] Step 3: Ta loading (Ta5@Fe-NC synthesis)

[0093] (1) Ta precursor load:

[0094] 50 mg of Fe-NC catalyst was dispersed in 5 mL of anhydrous ethanol to form a homogeneous suspension.

[0095] 5 μL of TaCl5-n-butanol solution (concentration 200 g / L) was precisely added to the suspension using a microsyringe, followed by ultrasonic treatment for 3 hours to ensure that TaCl5 was uniformly adsorbed on the Fe-NC surface;

[0096] Continue stirring for 2 hours to enhance the adsorption effect and obtain a mixed solution;

[0097] (2) Freeze-drying and high-temperature annealing:

[0098] The mixture was freeze-dried to obtain the TaCl5-modified Fe-NC precursor;

[0099] The TaCl5-modified Fe-NC precursor was placed in a tube furnace and annealed at 900°C for 30 minutes under an argon atmosphere. Then, it was switched to an ammonia atmosphere and held for 30 minutes. Finally, it was switched back to argon and naturally cooled to room temperature.

[0100] This process causes TaCl5 to decompose into Ta atoms, which are then loaded onto the Fe-NC surface in the form of clusters (approximately 2 nanometers in diameter), forming an indirect bonding structure (Fe-N-Ta). Ultimately, the Ta nanoclusters are loaded onto Fe-NC as a single-atom spin catalyst, labeled Ta5@Fe-NC.

[0101] The structural characterization and performance testing of the single-atom spin catalyst prepared in Example 1 are as follows:

[0102] 1. Structural characterization

[0103] Characterization of the single-atom spin catalyst prepared in Example 1 by spherical aberration electron microscopy clearly shows that many uniformly dispersed Ta clusters (such as...) are loaded on the Fe-NC substrate. Figure 1 Synchrotron radiation characterization showed the absence of Fe-Fe bonds, proving that Fe exists entirely in monatomic form (e.g., ...). Figure 2 ).

[0104] 2. Characterization of spin states

[0105] Through the hysteresis loop at room temperature (e.g.) Figure 3 It can be seen that the introduction of Ta clusters significantly improves the saturation magnetization of Fe. The regulatory mechanism is as follows: Ta clusters are indirectly bonded via Fe-N-Ta, and their strong spin-orbit coupling (SOC) effect is transmitted to the Fe atoms through nitrogen bridges, weakening the Fe-N bond strength and reducing the crystal field splitting energy (ΔT). s plit). When Δ s plit is lower than the spin exchange energy (Δ) e When xc), the electrons of Fe move from the low-energy orbital (t) 2g ) jump to a high-energy orbit (e g ), forming a high-spin state (e g 1 (Orbital occupation), significantly increasing the magnetic moment (to 3.68 μ). B ).

[0106] 3. Characterization of spin polarization (e.g.) Figure 4 (As shown)

[0107] The intersection of the temperature-dependent magnetic susceptibility curves represents the magnetic transition temperature (T). b ), T b Higher temperatures indicate stronger magnetic interactions, which means higher spin polarization. For Fe-NC (Comparative Example 1), T b The temperature is 345K, and the T of Fe-NC loaded with Ta clusters is... b Temperatures exceeding 400K not only indicate that Ta increases the spin polarizability of Fe, but also that high T... b Temperature also allows the catalyst to maintain magnetic order and a high spin polarization rate under actual operating conditions (95℃), which ensures that the spin-enhanced catalytic performance remains stable over a long period of time.

[0108] 4. OER performance testing (e.g.) Figure 5 (As shown)

[0109] Analysis of the electrocatalytic performance test curve (linear sweep voltammetry) showed that the turnover frequency (TOF) of pure Fe-NC (Comparative Example 1) was 0.19 s. -1 The TOF of Ta5@Fe-NC increased to 21.78 s after Ta cluster loading. -1 The performance has been improved by 115 times, which is the highest improvement in spin-controlled catalysis to date.

[0110] 5. ORR (Oxygen Reduction Reaction) performance test (e.g.) Figure 6 (As shown)

[0111] Analysis of the electrocatalytic performance test curve (linear sweep voltammetry) shows that the half-wave potential of Ta5@Fe-NC prepared in Example 1 increased from 0.86V to 0.94V, which is not only superior to commercial Pt / C catalysts, but also higher than most noble metal and non-noble metal catalysts currently studied.

[0112] 6. Performance comparison analysis (e.g.) Figure 7 (As shown)

[0113] The ORR performance of Ta5@Fe-NC prepared in Example 1 has a very significant advantage over most noble metal and non-noble metal catalysts currently available.

[0114] The Ta5@Fe-NC prepared in Example 1 exhibited the best OER and ORR performance. The OER overpotential was 244 mV, and the ORR half-wave potential was 0.94 V.

[0115] Comparative Example 1

[0116] Fe-NC was prepared according to steps one and two of Example 1. The OER overpotential of Fe-NC was 569mV, which is very poor, and the ORR half-wave potential was 0.86V.

[0117] Example 2

[0118] Compared with Example 1, the only difference in Example 2 is that the volume of the TaCl5-n-butanol solution (concentration 200 g / L) was changed to 0.5 μL, while other preparation conditions remained unchanged, resulting in a single-atom Ta-supported Fe-NC catalyst, labeled as Ta. 0.5 @Fe-NC

[0119] The overpotential of the catalyst's OER is 434 mV, which is much greater than the 244 mV of Ta5@Fe-NC, indicating a significant deterioration in performance. The half-wave potential of the ORR is 0.885 V.

[0120] Example 3

[0121] Compared with Example 1, the only difference in Example 3 is that the volume of the TaCl5-n-butanol solution (concentration 200 g / L) was changed to 30 μL, while other preparation conditions remained unchanged, resulting in a larger particle size Ta-supported Fe-NC catalyst, labeled as Ta. 30 @Fe-NC.

[0122] The catalyst exhibits a significantly reduced OER overpotential of 450 mV. Its ORR half-wave potential is 0.91, slightly better than Ta. 0.5 @Fe-NC, but still significantly worse than Ta5@Fe-NC (0.94V) with clustered Ta loading.

[0123] Comparative Example 2

[0124] Ta-supported NC, without Fe single-atom catalyst.

[0125] Compared to Example 1, Comparative Example 2 differs in that step two is omitted, and step three is performed directly after step one. This yields Ta-supported NC catalyst without Fe single-atom catalyst, denoted as Ta@NC.

[0126] The catalyst prepared in Comparative Example 2 had an OER overpotential higher than 590V, exhibiting almost no OER performance. Its ORR half-wave potential was around 0.8V, indicating particularly weak ORR performance.

[0127] The OER overpotential and ORR half-wave potential of the above embodiments and comparative examples were statistically analyzed, and the results are shown in Table 1.

[0128] Table 1

[0129]

[0130] As can be seen from Table 1, the catalysts prepared in the examples have better performance than those in the comparative examples. Among the examples, the catalyst prepared in Example 1 has the best performance.

Claims

1. A monatomic spin catalyst, characterized in that, The single atom spin catalyst comprises a magnetic element-NC substrate, and a heavy metal loaded on the magnetic element-NC substrate.

2. The monatomic spin catalyst of claim 1, wherein, The magnetic element-NC substrate refers to single atoms of Fe, Co or Ni dispersed in a N-doped carbon substrate in the form of magnetic element-N4; and / or, the heavy metal comprises at least one transition metal of Hf, Ta, W, Re, Os, Ir, Pt, Au and other atomic numbers greater than the magnetic element.

3. The monatomic spin catalyst of claim 1, wherein, The heavy metal comprises different micro-sizes of Hf, Ta, W, Re, Os, Ir, Pt, Au and at least one transition metal of other atomic numbers greater than the magnetic element, including single atoms, clusters or particles.

4. The monatomic spin catalyst of claim 3, wherein, The clusters of the heavy metal are indirectly bonded through "magnetic atom-N-heavy metal atom"; and / or, the diameter of the heavy metal cluster is 1-5 nm.

5. The monatomic spin catalyst of claim 1, wherein, There is no magnetic metal-magnetic metal bond in the single atom spin catalyst.

6. Process for the preparation of a monatomic spin catalyst as claimed in any one of claims 1-5, characterized in that, The single atom spin catalyst comprises the following steps: (1) Preparation of a carbon substrate: zinc acetate is dissolved to obtain solution A, 2,5-dihydroxyterephthalic acid is dissolved to obtain solution B, and salicylic acid is dissolved to obtain solution C, then solution A, solution B and solution C are mixed and reacted to obtain a precipitate, the precipitate is taken for hydrothermal reaction, dried to obtain a metal organic framework precursor, and then pyrolysis is performed under a protective gas atmosphere to prepare the carbon substrate; (2) Preparation of a magnetic element-NC substrate: a magnetic element salt and 1,10-phenanthroline are dissolved in a solvent to obtain solution D, then the carbon substrate is mixed with solution D, ultrasonic treatment is performed, and drying is performed to obtain a composite, then heat treatment is performed, and acid washing is performed to obtain the magnetic element-NC substrate; (3) Loading of a heavy metal: the magnetic element-NC substrate is dispersed in a solvent, then a heavy metal salt solution is added, and drying is performed to obtain a heavy metal salt modified magnetic element-NC precursor, and then annealing treatment is performed to prepare the single atom spin catalyst.

7. The production method according to claim 6, characterized by, In step (1), the reaction temperature of the hydrothermal reaction is 100-120 DEG C, and the hydrothermal reaction time is 24-36 hours; and / or, the pyrolysis temperature is 800-1000 DEG C, and the pyrolysis time is 2-4 hours; and / or, in step (1), the mass ratio of zinc acetate, 2,5-dihydroxyterephthalic acid and salicylic acid is 5.5:(1.0-5.0):(0.5-3).

8. The preparation method according to claim 6, characterized in that, In step (2), the mass ratio of the magnetic element salt, 1,10-phenanthroline and the carbon substrate is 20:(20-50):(90-110); and / or, in step (3), the heavy metal salt solution comprises an organic solution or an aqueous solution of a heavy metal chloride; and / or, the heavy metal chloride is at least one of HfCl4, TaCl5, WCl6, ReCl5, OsCl3, IrCl3 and H2[PtCl6].

9. The production method according to claim 8, characterized by, In step (3), the concentration of the n-butanol solution of TaCl5, one of the heavy metal salt solutions, is 180-220 g / L; and / or, in step (3), the dosage ratio of the magnetic element-NC substrate to the n-butanol solution of TaCl5 is 50 mg:(0.5-30) mu L.

10. Use of the monatomic spin catalyst of any one of claims 1 to 5 or the monatomic spin catalyst produced by the method of any one of claims 6 to 9 in the field of catalysis.

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