A method for preparing S-doped MNC oxygen reduction catalysts and the resulting products based on a molecular guest strategy.

Abstract

This invention provides a method for preparing S-doped M-N-C oxygen reduction catalysts based on a molecular guest strategy. The specific steps are as follows: 1) Weigh 1,10-phenanthroline, a sulfur source, and a metal salt according to the formula, and dissolve them in ethanol to obtain solutions A, B, and C, respectively. The sulfur source is a C atom with a lone pair of electrons bonded to at least one amino group; 2) Mix solution B and solution C, and stir at room temperature to obtain solution D; 3) Mix solution A and solution D, and stir at room temperature to obtain solution E; 4) Weigh the hard template according to the formula. 5) Add the solution to solution E and stir at room temperature to obtain solution F; 6) Transfer solution F to a water bath, heat and stir until dry to obtain product G; 7) Grind product G into powder, place it in a tube furnace and pyrolyze it once in an inert gas atmosphere, and cool it to room temperature to obtain material H; 8) Transfer material H to an acid solution, etch it to remove the hard template and the overmetal particles generated in step 6), and dry it under vacuum to obtain product I; 9) Transfer product I to a tube furnace and pyrolyze it a second time in an inert gas atmosphere, and cool it to room temperature to obtain S-doped M-N-C catalyst.

Description

Technical Field

[0001] This invention belongs to the field of fuel cell electrocatalyst preparation technology, and specifically relates to a method for preparing S-doped MNC oxygen reduction catalysts based on a molecular guest strategy and the resulting product. Background Technology

[0002] The oxygen reduction reaction (ORR) is a crucial cathode reaction in the discharge process of zinc-air batteries and fuel cells. Researchers are dedicated to developing highly active metal-neutral cathode (MNC) catalysts. Increasing the active site density is the most direct way to improve catalyst activity. However, constructing MNC catalysts with high-density active sites is often complex and prone to forming inactive metal clusters. Furthermore, since the catalytic activity of MNC catalysts is highly dependent on the electronic structure of the metal center, local structural coordination engineering has become a crucial method to improve the intrinsic activity of active sites. Introducing heteroatoms into the local coordination structure of active sites provides a feasible way to tune the electronic structure of active sites. In particular, both thiophene S and S oxide formed by S doping can induce charge redistribution at the metal center, thereby improving the intrinsic activity of MNC catalysts.

[0003] However, the S doping in the S-doped MNC catalysts reported in the literature is all formed during the pyrolysis process. The precursor does not involve specific interactions between metal atoms and S atoms, resulting in randomness in the structure of active sites in the final catalyst. This makes it impossible to guarantee the directional and precise construction of the structure type of S-doped MNC catalyst, and there is a lack of a general strategy for the preparation of S-doped MNC catalysts. Summary of the Invention

[0004] In view of this, the present invention aims to propose a method for preparing S-doped MNC oxygen reduction catalysts based on a molecular guest strategy, thereby improving the inherent activity of MNC catalysts.

[0005] This invention provides a method for preparing S-doped MNC oxygen reduction catalysts based on a molecular guest strategy, the specific steps of which are as follows:

[0006] 1) Weigh 1,10-phenanthroline, sulfur source and metal salt according to the formula, and dissolve them in ethanol to prepare solution A, solution B and solution C respectively. The sulfur source is a C atom with a lone pair of electrons connected to at least one amino group.

[0007] 2) Mix solution B and solution C, and stir at room temperature until homogeneous to obtain solution D;

[0008] 3) Mix solution A and solution D, and stir at room temperature until homogeneous to obtain solution E;

[0009] 4) Weigh the hard template according to the formula, add it to solution E, and stir at room temperature until homogeneous to obtain solution F;

[0010] 5) Transfer solution F to a water bath, heat, and stir until dry to obtain product G;

[0011] 6) Grind product G into powder, place it in a tube furnace and pyrolyze it once in an inert gas atmosphere, then cool it to room temperature to obtain material H;

[0012] 7) Transfer material H to an acid solution for etching to remove the hard template and the metal particles generated in step 6). After drying under vacuum, product I is obtained.

[0013] 8) Product I was transferred to a tube furnace and subjected to secondary pyrolysis in an inert gas atmosphere. After cooling to room temperature, the S-doped MNC catalyst was obtained.

[0014] Furthermore, the formulations for using the 1,10-phenanthroline, hard template, sulfur source, and metal salt are as follows:

[0015]

[0016] Furthermore, the sulfur source is one or a combination of several of thiourea, thioacetamide, allyl thiourea, and trithiocyanate.

[0017] Furthermore, the metal salt is one or a combination of several of ferric chloride, cobalt chloride, manganese chloride, tin chloride, copper chloride, cerium chloride, and ruthenium chloride.

[0018] Furthermore, the hard template is any one or a combination of several of nano-SiO2, nano-ZnO, nano-MgO, nano-Al2O3 and nano-polystyrene spheres.

[0019] Furthermore, in step 5), the water bath temperature is 50–70°C.

[0020] Furthermore, the inert gas in steps 6) and 8) is any one of high-purity nitrogen, high-purity argon, and argon-hydrogen mixture.

[0021] Furthermore, the conditions for the primary and secondary pyrolysis in steps 6) and 8) are 5℃·min. -1 The heating rate is increased from room temperature to 700-1050℃ for pyrolysis, and the pyrolysis time is 1-5 hours.

[0022] Furthermore, in step 7), the acid solution is one or a combination of hydrofluoric acid, hydrochloric acid, and sulfuric acid; the etching time is 6–12 h; and the drying conditions are vacuum drying at 60 °C for 12–24 h.

[0023] In another aspect, the present invention provides an S-doped MNC oxygen reduction catalyst prepared by the above preparation method.

[0024] Beneficial effects:

[0025] (1) The method for preparing S-doped MNC oxygen reduction catalysts based on a molecular guest strategy provided by this invention uses S (where the C atom with a lone pair of electrons is connected to at least one amino group) as the molecular guest. The molecular guest can not only coordinate with the metal center, but its pyrolysis also facilitates the formation of active thiophene sulfide (CSC), thus simultaneously enhancing ORR activity. In contrast, the coordination between a typical sulfur source and the metal center is difficult to control, and due to the presence of a large amount of O, pyrolysis often results in the formation of a large amount of inactive sulfur oxides (C-SO₄). X The metal center with empty d orbitals serves as the host structure. The MN / SC structure is formed by the lone electrons of S atoms filling the empty orbitals of the metal center (coordinate bonding). During pyrolysis, the S atoms are anchored within the carbon framework, forming a stable, locally coordinated structure. Furthermore, because S atoms have lower electronegativity and a larger atomic radius than N atoms, they facilitate breaking the symmetry of the MNC structure, optimizing the electronic structure of the metal center, improving the adsorption strength between active sites and oxygen-containing intermediates, and enhancing ORR activity.

[0026] (2) The preparation process of the S-doped MNC oxygen reduction catalyst based on the molecular guest strategy provided by the present invention is simple, effective and universal, which is conducive to large-scale application and preparation. Attached Figure Description

[0027] Figure 1 The image shows a transmission electron microscope (TEM) image of the FeNSC-allyl thiourea catalyst prepared in Example 1.

[0028] Figure 2 Example 1 shows the preparation of the FeNSC-allyl thiourea catalyst, and Example 2 shows the linear sweep voltammetry (LSV) curves of the FeNSC-thiourea catalyst and the FeNSC-thioacetic acid catalyst of Comparative Example 1.

[0029] Figure 3 The LSV diagrams show the FeNSC-allyl thiourea catalyst prepared in Example 1 and the FeNSC-A allyl thiourea catalyst prepared in Comparative Example 2.

[0030] Figure 4 The X-ray photoelectron spectroscopy (XPS) high-resolution spectrum (S2p) of the FeNSC-allyl thiourea catalyst prepared in Example 1 is shown.

[0031] Figure 5The X-ray diffraction (XRD) patterns of the MnNSC catalyst prepared in Example 3, the CuNSC catalyst prepared in Example 4, and the CeNSC catalyst prepared in Example 5 are shown. Detailed Implementation

[0032] To make the above-mentioned objectives, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the examples in the specification. Unless otherwise specified, the methods described are conventional methods, and the raw materials described are available from publicly available commercial sources unless otherwise specified.

[0033] The term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The phrase "in one embodiment" appearing in different places throughout this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0034] The method for preparing an S-doped MNC oxygen reduction catalyst based on a molecular guest strategy provided by this invention comprises the following steps:

[0035] 1) Weigh 1,10-phenanthroline, sulfur source and metal salt according to the formula, and dissolve them in ethanol to prepare solution A, solution B and solution C respectively. The sulfur source is a C atom with a lone pair of electrons connected to at least one amino group.

[0036] 2) Mix solution B and solution C, and stir at room temperature until homogeneous to obtain solution D;

[0037] 3) Mix solution A and solution D, and stir at room temperature until homogeneous to obtain solution E;

[0038] 4) Weigh the hard template according to the formula, add it to solution E, and stir at room temperature until homogeneous to obtain solution F;

[0039] 5) Transfer solution F to a water bath, heat, and stir until dry to obtain product G;

[0040] 6) Grind product G into powder, place it in a tube furnace and pyrolyze it once in an inert gas atmosphere, then cool it to room temperature to obtain material H;

[0041] 7) Transfer material H to an acid solution for etching to remove the hard template and the metal particles generated in step 6). After drying under vacuum, product I is obtained.

[0042] 8) The product I was transferred to a tube furnace and pyrolyzed again in an inert gas atmosphere. After cooling to room temperature, the S-doped MNC catalyst was obtained.

[0043] According to the present invention, preferably, the sulfur source is one or a combination of several of thiourea, thioacetamide, allyl thiourea, and trithiocyanate; the metal salt is one or a combination of several of ferric chloride, cobalt chloride, manganese chloride, tin chloride, copper chloride, cerium chloride, and ruthenium chloride; the hard template is any one or a combination of several of nano-SiO2, nano-ZnO, nano-MgO, nano-Al2O3, and nano-polystyrene spheres; the water bath temperature in step 5) is 50–70°C; the inert gas in steps 6) and 8) is any one of high-purity nitrogen, high-purity argon, and an argon-hydrogen mixture; the conditions for the primary and secondary pyrolysis in steps 6) and 8) are 5°C·min. -1 The heating rate is increased from room temperature to 700-1050℃ for pyrolysis, and the pyrolysis time is 1-5h. In step 7), the acid solution is one or a combination of hydrofluoric acid, hydrochloric acid and sulfuric acid. The etching time is 6-12h. The drying conditions are vacuum drying at 60℃ for 12-24h.

[0044] Example 1

[0045] 1) Weigh 0.4g of 1,10-phenanthroline, 0.309g of allyl thiourea and 1 mmol of FeCl3·6H2O respectively, and dissolve them in ethanol to prepare solutions A, B and C respectively;

[0046] 2) Mix solution B and solution C, and stir at room temperature for 30 minutes to make them homogeneous, thus obtaining solution D;

[0047] 3) Mix solution A with solution D and stir at room temperature for 60 minutes to make it homogeneous, thus obtaining solution E;

[0048] 4) Weigh 0.5g of SiO2 and add it to solution E. Stir at room temperature for 60 minutes to make it uniform and obtain solution E.

[0049] 5) Transfer solution E to a water bath, heat to 70°C, and stir until dry to obtain product F;

[0050] 6) Grind product F into powder, place it in a tube furnace and pyrolyze it once at 850°C for 2 hours in an inert gas atmosphere, and cool it to room temperature to obtain material G;

[0051] 7) Transfer material G to hydrofluoric acid for etching to remove the hard template and the metal particles generated in step 6). Dry the material at 60°C for 12 hours under vacuum to obtain product H.

[0052] 8) The product H was transferred to a tube furnace and pyrolyzed again at 850°C for 2 hours in an inert gas atmosphere. After cooling to room temperature, the S-doped FeNSC catalyst was obtained.

[0053] It is designated as FeNSC-allyl thiourea catalyst.

[0054] Transmission electron microscopy (TEM) image of FeNSC-allyl thiourea catalyst, as shown Figure 1 As shown.

[0055] Example 2

[0056] 1) Weigh 0.4g of 1,10-phenanthroline, 0.202g of thiourea and 1 mmol of FeCl3·6H2O respectively, and dissolve them in ethanol to prepare solutions A, B and C respectively;

[0057] 2) Mix solution B and solution C, and stir at room temperature for 30 minutes to make them homogeneous, thus obtaining solution D;

[0058] 3) Mix solution A with solution D and stir at room temperature for 60 minutes to make it homogeneous, thus obtaining solution E;

[0059] 4) Weigh 2g of SiO2 and add it to solution E. Stir at room temperature for 60 minutes to make it uniform and obtain solution E.

[0060] 5) Transfer solution E to a water bath, heat to 50°C, and stir until dry to obtain product F;

[0061] 6) Grind product F into powder, place it in a tube furnace and pyrolyze it at 1050℃ for 1 hour in an inert gas atmosphere, and cool it to room temperature to obtain material G;

[0062] 7) Transfer material G to hydrofluoric acid for etching to remove the hard template and the metal particles generated in step 6). Dry the material at 60°C for 24 hours under vacuum to obtain product H.

[0063] 8) The product H was transferred to a tube furnace and pyrolyzed again at 1050℃ for 1 h in an inert gas atmosphere. After cooling to room temperature, the S-doped FeNSC catalyst was obtained.

[0064] It is designated as FeNSC-allyl thiourea catalyst.

[0065] Example 3

[0066] 1) Weigh 0.4g of 1,10-phenanthroline, 0.202g of thiourea and 1 mmol of MnCl2·4H2O respectively, and dissolve them in ethanol to prepare solutions A, B and C respectively;

[0067] 2) Mix solution B and solution C, and stir at room temperature for 30 minutes to make them homogeneous, thus obtaining solution D;

[0068] 3) Mix solution A with solution D and stir at room temperature for 60 minutes to make it homogeneous, thus obtaining solution E;

[0069] 4) Weigh 2g of SiO2 and add it to solution E. Stir at room temperature for 60 minutes to make it uniform and obtain solution E.

[0070] 5) Transfer solution E to a water bath, heat to 50°C, and stir until dry to obtain product F;

[0071] 6) Grind product F into powder, place it in a tube furnace and pyrolyze it at 900°C for 1 hour in an inert gas atmosphere, and cool it to room temperature to obtain material G;

[0072] 7) Transfer material G to hydrofluoric acid for etching to remove the hard template and the metal particles generated in step 6). Dry the material at 60°C for 12 hours under vacuum to obtain product H.

[0073] 8) The product H was transferred to a tube furnace and pyrolyzed again at 900°C for 1 hour in an inert gas atmosphere. After cooling to room temperature, the S-doped MnNSC catalyst was obtained.

[0074] It is designated as MnNSC catalyst.

[0075] Example 4

[0076] 1) Weigh 0.4g of 1,10-phenanthroline, 0.202g of thiourea and 1 mmol of CuCl2·4H2O respectively, and dissolve them in ethanol to prepare solutions A, B and C respectively;

[0077] 2) Mix solution B and solution C, and stir at room temperature for 30 minutes to make them homogeneous, thus obtaining solution D;

[0078] 3) Mix solution A with solution D and stir at room temperature for 60 minutes to make it homogeneous, thus obtaining solution E;

[0079] 4) Weigh 2g of SiO2 and add it to solution E. Stir at room temperature for 60 minutes to make it uniform and obtain solution E.

[0080] 5) Transfer solution E to a water bath, heat to 50°C, and stir until dry to obtain product F;

[0081] 6) Grind product F into powder, place it in a tube furnace and pyrolyze it at 950°C for 3 hours in an inert gas atmosphere, and cool it to room temperature to obtain material G;

[0082] 7) Transfer material G to hydrofluoric acid for etching to remove the hard template and the metal particles generated in step 6). Dry the material at 60°C for 12 hours under vacuum to obtain product H.

[0083] 8) The product H was transferred to a tube furnace and pyrolyzed again at 950°C for 3 hours in an inert gas atmosphere. After cooling to room temperature, the S-doped CuNSC catalyst was obtained.

[0084] It is designated as CuNSC catalyst.

[0085] Example 5

[0086] 1) Weigh 0.4g of 1,10-phenanthroline, 0.202g of thiourea and 1 mmol of CuCl2·4H2O respectively, and dissolve them in ethanol to prepare solutions A, B and C respectively;

[0087] 2) Mix solution B and solution C, and stir at room temperature for 30 minutes to make them homogeneous, thus obtaining solution D;

[0088] 3) Mix solution A with solution D and stir at room temperature for 60 minutes to make it homogeneous, thus obtaining solution E;

[0089] 4) Weigh 3g of SiO2 and add it to solution E. Stir at room temperature for 60 minutes to make it uniform and obtain solution E.

[0090] 5) Transfer solution E to a water bath, heat to 50°C, and stir until dry to obtain product F;

[0091] 6) Grind product F into powder, place it in a tube furnace and pyrolyze it at 950°C for 3 hours in an inert gas atmosphere, and cool it to room temperature to obtain material G;

[0092] 7) Transfer material G to hydrofluoric acid for etching to remove the hard template and the metal particles generated in step 6). Dry the material at 60°C for 12 hours under vacuum to obtain product H.

[0093] 8) The product H was transferred to a tube furnace and pyrolyzed again at 950°C for 3 hours in an inert gas atmosphere. After cooling to room temperature, the S-doped CeNSC catalyst was obtained.

[0094] It is designated as CeNSC catalyst.

[0095] Comparative Example 1

[0096] 1) Weigh 0.4g of 1,10-phenanthroline, 0.202g of thioacetic acid and 1 mmol of FeCl3·6H2O respectively, and dissolve them in ethanol to prepare solutions A, B and C respectively;

[0097] 2) Mix solution B and solution C, and stir at room temperature for 30 minutes to make them homogeneous, thus obtaining solution D;

[0098] 3) Mix solution A with solution D and stir at room temperature for 60 minutes to make it homogeneous, thus obtaining solution E;

[0099] 4) Weigh 3g of SiO2 and add it to solution E. Stir at room temperature for 60 minutes to make it uniform and obtain solution E.

[0100] 5) Transfer solution E to a water bath, heat to 50°C, and stir until dry to obtain product F;

[0101] 6) Grind product F into powder, place it in a tube furnace and pyrolyze it at 950°C for 3 hours in an inert gas atmosphere, and cool it to room temperature to obtain material G;

[0102] 7) Transfer material G to hydrofluoric acid for etching to remove the hard template and the metal particles generated in step 6). Dry the material at 60°C for 12 hours under vacuum to obtain product H.

[0103] 8) The product H was transferred to a tube furnace and pyrolyzed for 3 hours at 950°C in an inert gas atmosphere. After cooling to room temperature, the S-doped FeNSC-thioacetic acid catalyst was obtained.

[0104] It is designated as FeNSC-thioacetic acid catalyst.

[0105] Comparative Example 2

[0106] 1) Weigh 0.4g of 1,10-phenanthroline, 0.309g of allyl thiourea and 1 mmol of FeCl3·6H2O respectively, and dissolve them in ethanol to prepare solutions A, B and C respectively;

[0107] 2) Mix solution B and solution C, and stir at room temperature for 30 minutes to make them homogeneous, thus obtaining solution D;

[0108] 3) Mix solution A with solution D and stir at room temperature for 60 minutes to make it homogeneous, thus obtaining solution E;

[0109] 4) Weigh 0.5g of SiO2 and add it to solution E. Stir at room temperature for 60 minutes to make it uniform and obtain solution E.

[0110] 5) Transfer solution E to a water bath, heat to 70°C, and stir until dry to obtain product F;

[0111] 6) Grind product F into powder, place it in a tube furnace and pyrolyze it once at 850°C for 2 hours in an inert gas atmosphere, and cool it to room temperature to obtain material G;

[0112] 7) Transfer material G to hydrofluoric acid for etching to remove the hard template and the metal particles generated in step 6). After drying at 60°C under vacuum for 12 hours, S-doped FeNSC catalyst is obtained.

[0113] Designated as FeNSC-A allylthiourea catalyst

[0114] The catalysts prepared in the above-described examples and comparative examples were respectively subjected to a concentration of 0.6 mg·cm⁻¹. -2The amount of material was uniformly loaded onto different glassy carbon electrodes as working electrodes, and three-electrode electrochemical tests were performed (using Hg / Hg2SO4 electrode as reference electrode and graphite electrode as counter electrode).

[0115] Figure 2 Linear sweep voltammetry (LSV) curves were used to measure the ORR performance of the catalysts prepared in Examples 1, 2, and Comparative Example 1 in a 0.1 mol·L⁻¹ HClO₄ aqueous electrolyte. The FeNSC-allyl thiourea catalyst prepared in Example 1 exhibited the best ORR catalytic performance with an onset potential of 0.89 V and a half-wave potential of 0.79 V. The FeNSC-thiourea catalyst prepared in Example 2 showed ORR performance similar to that of Example 1, but superior to that of the FeNSC-thioacetic acid catalyst described in Comparative Example 1.

[0116] Figure 3 The ORR performance graphs of the FeNSC-allyl thiourea catalyst prepared in Example 1 and the FeNSC-A allyl thiourea catalyst prepared in Comparative Example 2 are shown. The comparison demonstrates that secondary pyrolysis is beneficial to improving the ORR activity of the catalyst.

[0117] Figure 4 The X-ray photoelectron spectroscopy (XPS) high-resolution spectrum of the FeNSC-allyl thiourea catalyst prepared in Example 1 shows that the S species in the prepared catalyst exist in two forms: CSC (thiophene S) and C-SOx-C (oxidized S). This is beneficial for regulating the electronic structure of the Fe metal center and improving the catalytic performance of the catalyst.

[0118] Figure 5 The X-ray diffraction (XRD) patterns of the MnNSC catalyst prepared in Example 3, the CuNSC catalyst prepared in Example 4, and the CeNSC catalyst prepared in Example 5 are shown. The analysis verifies that the catalysts prepared by the strong coordination effect of 1,10-phenanthroline with metal and the spatial isolation strategy of hard template provided by the present invention do not contain metal particles, and have a certain degree of universality for different metal raw materials.

[0119] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing S-doped MNC oxygen reduction catalysts based on a molecular guest strategy, characterized in that, The specific steps are as follows: 1) Weigh 1,10-phenanthroline, sulfur source and metal salt according to the formula, and dissolve them in ethanol to prepare solution A, solution B and solution C respectively. The sulfur source is a C atom with a lone pair of electrons connected to at least one amino group. 2) Mix solution B and solution C, and stir at room temperature until homogeneous to obtain solution D; 3) Mix solution A and solution D, and stir at room temperature until homogeneous to obtain solution E; 4) Weigh the hard template according to the formula, add it to solution E, and stir at room temperature until homogeneous to obtain solution F; 5) Transfer solution F to a water bath, heat, and stir until dry to obtain product G; 6) Grind product G into powder, place it in a tube furnace and pyrolyze it once in an inert gas atmosphere, then cool it to room temperature to obtain material H; 7) Transfer material H to an acid solution for etching to remove the hard template and the metal particles generated in step 6). After drying under vacuum, product I is obtained. 8) Product I was transferred to a tube furnace and subjected to secondary pyrolysis in an inert gas atmosphere. After cooling to room temperature, the S-doped MNC catalyst was obtained. The formulations for the use of 1,10-phenanthroline, hard template, sulfur source, and metal salt are as follows: 1,10-Phenanthroline 0.2–1 mmol Hard template 0.3~3.0 g Sulfur source 0.2~1.6 g Metal salt 1~5 mmol.

2. The preparation method for S-doped MNC oxygen reduction catalyst based on molecular guest strategy as described in claim 1, characterized in that, The sulfur source is one or a combination of several of thiourea, thioacetamide, allyl thiourea, and trithiocyanate.

3. The preparation method for S-doped MNC oxygen reduction catalyst based on molecular guest strategy as described in claim 1, characterized in that, The metal salt is one or a combination of several of the following: ferric chloride, cobalt chloride, manganese chloride, tin chloride, copper chloride, cerium chloride, and ruthenium chloride.

4. The preparation method for S-doped MNC oxygen reduction catalyst based on molecular guest strategy as described in claim 1, characterized in that, The hard template is any one or a combination of several of the following: nano-SiO2, nano-ZnO, nano-MgO, nano-Al2O3, and nano-polystyrene spheres.

5. The preparation method for S-doped MNC oxygen reduction catalyst based on molecular guest strategy as described in claim 1, characterized in that, In step 5), the water bath temperature is 50~70℃.

6. The preparation method for S-doped MNC oxygen reduction catalyst based on molecular guest strategy as described in claim 1, characterized in that, In steps 6) and 8), the inert gas is any one of high-purity nitrogen, high-purity argon, and argon-hydrogen mixture.

7. The preparation method for S-doped MNC oxygen reduction catalyst based on molecular guest strategy as described in claim 1, characterized in that, The conditions for the primary and secondary pyrolysis in steps 6) and 8) are 5℃·min. -1 The heating rate is increased from room temperature to 700-1050℃ for pyrolysis, and the pyrolysis time is 1-5 h.

8. The preparation method for S-doped MNC oxygen reduction catalyst based on molecular guest strategy as described in claim 1, characterized in that, In step 7), the acid solution is one or a combination of hydrofluoric acid, hydrochloric acid and sulfuric acid. The etching time is 6 to 12 hours, and the drying conditions are vacuum drying at 60°C for 12 to 24 hours.

9. An S-doped MNC oxygen reduction catalyst prepared by the method for preparing S-doped MNC oxygen reduction catalyst based on the molecular guest strategy according to any one of claims 1-8.

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