WO2024216565A1 - 一种金属双原子材料及其制备方法和用途 - Google Patents

一种金属双原子材料及其制备方法和用途 Download PDF

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WO2024216565A1
WO2024216565A1 PCT/CN2023/089387 CN2023089387W WO2024216565A1 WO 2024216565 A1 WO2024216565 A1 WO 2024216565A1 CN 2023089387 W CN2023089387 W CN 2023089387W WO 2024216565 A1 WO2024216565 A1 WO 2024216565A1
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metal
diatomic
etched
solution
single atom
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English (en)
French (fr)
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孙晓明
金祥荣
常梦瑶
刘�文
常铮
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Beijing University of Chemical Technology
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Beijing University of Chemical Technology
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Priority claimed from CN202310404217.8A external-priority patent/CN118825305A/zh
Priority claimed from CN202310404214.4A external-priority patent/CN118825297A/zh
Priority claimed from CN202310404213.XA external-priority patent/CN118825296A/zh
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/24—Nitrogen compounds
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00—Electrodes
    • H01M4/86—Inert electrodes with catalytic activity, e.g. for fuel cells
    • H01M4/90—Selection of catalytic material

Definitions

  • the invention belongs to the technical field of electrocatalysis, and in particular relates to a metal diatomic material and a preparation method and application thereof.
  • the rate of oxygen reduction reaction at the cathode is slower than that at the anode due to the four-electron process involved, and is the rate-determining step of the battery reaction in hydrogen-oxygen fuel cells. Therefore, it is necessary to use efficient catalysts to increase the rate of oxygen reduction reaction.
  • precious metal catalysts have been active in current research due to their unique catalytic properties. Although precious metal catalysts have excellent catalytic performance, the large-scale use of precious metal catalysts such as platinum carbon is severely limited due to serious problems such as limited reserves and high costs of precious metals such as Pt, Pd, Ru, Ir, and the characteristics of being non-renewable resources. Therefore, it is necessary to gradually adopt substitutes to reduce the use of precious metals. Compared with precious metals, non-precious metals have a richer content in nature and are cheaper in the market, so they are more suitable for the overall requirements of long-term sustainable development.
  • diatomic metal catalysts with higher metal atom loading and more flexible active sites are the focus of future research. While diatomic catalysts have the advantages of fully exposed active sites, high selectivity, and up to 100% atomic utilization, the synergistic effect between the two adjacent different metals can further promote the breaking of the O-O bond, break the linear relationship between the adsorption energy of the reaction intermediates, increase the metal loading and oxygen reduction rate, and have great application potential, suitable for fuel cells and zinc-air batteries.
  • the currently synthesized metal diatomic materials usually use one-pot hydrothermal methods, pre-constrained metal atom pairs strategies, heteroatom doping strategies, etc. to anchor different metal atoms in order to synthesize metal diatomic materials.
  • the metal diatomic materials synthesized by these methods have fewer metal atom pairs; and the strategy used to synthesize diatoms is usually one-pot synthesis, and the synthesis of diatoms is random and uncertain.
  • reference 1 Wang Y, Li Z, Zhang P, et al. Flexible carbon nanofiber film with diatomic Fe-Co sites for efficient oxygen reduction and evolution reactions in Wearable zinc-air batteries[J].Nano Energy,2021,87. ⁇ As shown in Figure 1, at a scale of 2 nanometers, that is, 156.11 square nanometers, there are 9 pairs of metal diatomic materials, and the number of atomic pairs is relatively small. The smaller number of diatomic atoms also affects the electrocatalytic oxygen reduction activity, four-electron selectivity, and cycle stability of the metal diatomic material.
  • Figure 2 of the reference shows that the Fe 1 Co 1 -CNF metal diatomic material The half-wave potential is only 0.87V (Note: the larger the half-wave potential value, the greater the activity).
  • reference 2 Zhong X, Ye S, Tang J, et al. Engineering Pt and Fe dual-metal single atoms anchored on nitrogen-doped carbon with high activity and durability towards oxygen reduction reaction for zinc-air battery [J].
  • Applied Catalysis B: Environmental, 2021, 286: 119891 uses a bimetallic atomic catalyst synthesized by high-temperature calcination method. It can be seen from Figure 1d of reference 2 that at a scale of 2 nanometers, that is, 1126.388 square nanometers, there are 15 pairs of bimetallic atoms, and the number of atomic pairs is relatively small.
  • the smaller number of diatoms also affects the electrocatalytic oxygen reduction activity, four-electron selectivity, and cycle stability of the bimetallic atom catalyst.
  • the half-wave potential of the PtFe-NC bimetallic atom catalyst is 0.895V (Note: the larger the half-wave potential value, the greater the activity).
  • the hydrogen peroxide yield of the PtFe-NC bimetallic atom catalyst is less than 5% in the potential range of 0.1-0.8V (Note: the lower the hydrogen peroxide yield, the wider the potential range, and the higher the 4-electron selectivity).
  • the cycle stability of the PtFe-NC bimetallic atom catalyst is poor (Note: the smaller the negative shift value of the half-wave potential, the longer the cycle time, and the higher the cycle stability).
  • Figure S26b in reference 2 after 5000 CV cycles, the half-wave potential of the PtFe-NC bimetallic atom catalyst was negatively shifted by 13mV, and the stability was poor. The smaller number of diatoms leads to the poor oxygen reduction activity, four-electron selectivity, and cycle stability of the bimetallic atom catalyst.
  • this paper has developed a method for the controllable synthesis of metal diatomic materials using a peroxide etching method to synthesize high-density metal diatomic materials.
  • This synthesis method can effectively and controllably synthesize diatoms of a specified combination.
  • the metal diatomic materials prepared by this synthesis method have excellent oxygen reduction activity, four-electron selectivity and cyclic stability.
  • the metal diatomic material ZnFeNC prepared by hydrogen peroxide etching also has 56 pairs of dimetallic atomic pairs at a scale of 2 nanometers, and the density of atomic pairs is higher, indicating that this synthesis method has unique advantages and a higher success rate in synthesizing dimetallic atomic pairs.
  • the metal diatomic material ZnFeNC prepared by hydrogen peroxide etching has 56 pairs of dimetallic atomic pairs at a scale of 2 nanometers.
  • the half-wave potential of the sub-material CoFeNC is 0.86 V. This shows that the metal diatomic material prepared by the peroxide etching method has excellent catalytic oxygen reduction activity, selectivity and cycle stability.
  • a first aspect of the present invention provides a metal diatomic material, which comprises: a conductive substrate and a first metal single atom and a second metal single atom loaded on the conductive substrate, wherein the distance between the first metal single atom and the second metal single atom is less than or equal to 0.5 nanometers.
  • a first metal single atom and an adjacent second metal single atom form a diatomic pair, and the density of the diatomic pairs is not less than 0.06 pairs/square nanometer.
  • the density of diatomic pairs is not less than 0.08 pairs/square nanometer.
  • the density of diatomic pairs is 0.09 pairs/square nanometer (26 pairs/275 nanometers) to 0.21 pairs/square nanometer (56 pairs/265 nanometers).
  • the density of diatomic pairs is 0.10 pairs/square nanometer (57 pairs/555 nanometers) to 0.21 pairs/square nanometer (56 pairs/265 nanometers).
  • the distance between the first metal single atom and the second metal single atom is 0.1 to 0.5 nanometers.
  • the distance between the first metal single atom and the second metal single atom is 0.11 to 0.5 nanometers.
  • the first metal in the first metal single atom is selected from: one or more of cobalt, iron, zinc, nickel, manganese, platinum, ruthenium, iridium, gold, and silver;
  • the second metal in the second metal single atom is selected from: one or more of cobalt, iron, zinc, nickel, manganese, platinum, ruthenium, iridium, gold, and silver.
  • the first metal in the first metal single atom is selected from the group consisting of cobalt, iron, zinc, nickel, manganese, platinum, ruthenium, iridium, gold, and silver
  • the second metal in the second metal single atom is selected from the group consisting of cobalt, iron, zinc, nickel, manganese, platinum, ruthenium, iridium, gold, and silver
  • a variety of diatomic pairs of different metal types may exist on the conductive substrate.
  • the first metal in the first metal single atom is selected from cobalt and iron
  • the second metal in the second metal single atom is selected from nickel
  • the diatomic pairs present on the conductive substrate are: cobalt-nickel diatomic pairs and iron-nickel diatomic pairs.
  • the first metal in the first metal single atom is selected from cobalt and iron
  • the second metal in the second metal single atom is selected from nickel and manganese
  • the diatomic pairs present on the conductive substrate are: cobalt-nickel diatomic pairs, iron-nickel diatomic pairs, cobalt-manganese diatomic pairs and iron-manganese diatomic pairs.
  • the first metal single atom and the second metal single atom are the same as or different from each other.
  • the conductive substrate is selected from: nitrogen-carbon material or sulfur-nitrogen-carbon material.
  • the sites of the etched nitrogen-carbon material or sulfur-nitrogen-carbon material are carbon atoms, so more nitrogen atoms are exposed, which increases the nitrogen/carbon ratio and can effectively adsorb the second metal single atom.
  • the first metal single atom is an iron single atom
  • the second metal single atom is a platinum single atom
  • the distance between the iron single atom and the platinum single atom is 0.14 to 0.5 nanometers.
  • the density of diatomic pairs is not less than 0.06 pairs/square nanometer.
  • the density of the diatomic pairs is 0.09 pairs/nm2 (15 pairs/158.24 nm2) to 0.18 pairs/nm2 (21 pairs/112 nm2).
  • the first metal single atom is a cobalt single atom
  • the second metal single atom is an iron single atom
  • the distance between a single cobalt atom and a single iron atom is 0.1 to 0.5 nanometers.
  • the distance between a cobalt atom and an iron atom is 0.15 to 0.5 nanometers.
  • a cobalt single atom and an adjacent iron single atom form a diatomic pair.
  • the density of diatomic pairs is not less than 0.06 pairs/square nanometer.
  • the density of diatomic pairs is 0.10 pairs/square nanometer (29 pairs/280 square nanometers) to 0.16 pairs/square nanometer (44 pairs/280 square nanometers).
  • the second aspect of the present invention provides a method for preparing the metal diatomic material according to the first aspect, the preparation method comprising the following steps:
  • Etching placing the conductive substrate loaded with the first metal single atom in a peroxide aqueous solution for etching to obtain an etched first metal single atom material;
  • Preparation of metal diatomic material The first metal single atom material obtained after etching is loaded with the second metal single atom to obtain the metal diatomic material.
  • the specific method of etching is as follows:
  • Step A mixing alcohol and water into a solution, placing a conductive substrate loaded with a first metal single atom in the mixed solution, and performing ultrasound treatment;
  • Step B stirring the mixed solution obtained in step A, and uniformly adding a peroxide aqueous solution to obtain a uniformly mixed reaction solution;
  • Step C transferring the reaction solution obtained in step B to a high-pressure reactor, placing it in an oven, setting the reaction temperature to 100°C to 200°C, and reacting for 3-10 hours; after the reaction is completed, filtering and washing the solid material obtained in the high-pressure reactor, and vacuum freeze-drying it to obtain the etched first metal single Atomic material.
  • the concentration of the conductive substrate loaded with the first metal single atom is 1 mg/mL-5 mg/mL, and the concentration of the peroxide is 0.1 mol/L-1.0 mol/L.
  • the specific method for preparing the metal diatomic material is as follows:
  • the etched first metal single atom material is dissolved in a mixed solution of alcohol and water, and ultrasonicated until a uniformly dispersed turbid solution is obtained, and an appropriate amount of a second metal precursor is weighed and added to the turbid solution to obtain a mixed solution, which is mixed uniformly, and the solid-liquid separation is performed, and the obtained solid material is vacuum freeze-dried;
  • the solid material obtained after freeze-drying is placed in a porcelain boat, carbonized under the protection of an inert gas, and then naturally cooled to room temperature to finally obtain a metal diatomic material.
  • the concentration of the first metal single atom material after etching is 1 mg/mL-5 mg/mL, and the concentration of the second metal precursor is 0.001 mol/L ⁇ 0.024 mol/L.
  • the peroxide in the aqueous peroxide solution is selected from one or more of hydrogen peroxide, peroxodisulfate, persulfate, peracetate, peroxyphosphate or peroxycarbonate.
  • the preparation method of the conductive substrate loaded with the first metal single atom is as follows:
  • the preparation method of the conductive substrate loaded with the first metal single atom is as follows:
  • the first metal in the first metal salt is selected from one or more of cobalt, iron, zinc, nickel, manganese, platinum, ruthenium, iridium, gold, and silver.
  • the first metal salt can be a first metal nitrate, a first metal sulfate, or a first metal chloride.
  • the precursor of the second metal is a second metal salt
  • the second metal is selected from: one or more of cobalt, iron, zinc, nickel, manganese, platinum, ruthenium, iridium, gold, and silver.
  • the second metal salt can be a second metal nitrate, a second metal sulfate, or a second metal chloride.
  • the third aspect of the present invention provides use of the metal diatomic material described in the first aspect for catalyzing oxygen reduction reactions.
  • the present invention has the following beneficial effects:
  • the present invention uses a single-atom metal material as a substrate (including but not limited to a single-atom metal nitrogen-carbon material), etches the single-atom metal material with peroxide to form a porous and defect-rich metal nitrogen-carbon material, and impregnates the material with a second metal precursor to form a diatomic metal nitrogen-carbon catalytic material with an atomic spacing of 0 to 0.5 nanometers.
  • a single-atom metal material as a substrate (including but not limited to a single-atom metal nitrogen-carbon material), etches the single-atom metal material with peroxide to form a porous and defect-rich metal nitrogen-carbon material, and impregnates the material with a second metal precursor to form a diatomic metal nitrogen-carbon catalytic material with an atomic spacing of 0 to 0.5 nanometers.
  • the metal diatomic materials prepared by the one-pot hydrothermal method have a higher diatomic density, the method of the present invention is more controllable, and the success probability of diatomic sites is high.
  • the present invention uses a method of peroxide oxidation etching of metal single-atom materials to effectively create defects and vacancies to synthesize atomically dispersed hetero-diatomic metal nitrogen-carbon catalysts.
  • This synthesis method is universal and can synthesize hetero-diatomic metal catalysts and homo-diatomic metal catalysts.
  • the hetero diatomic metal catalyst of the present invention has It has excellent oxygen reduction performance under alkaline conditions.
  • the half-wave potential of oxygen reduction of ZnFeNC metal diatomic material is 0.876V.
  • the first metal single atom and the second metal single atom are different, it is a heterodiatomic metal catalyst material.
  • the synergistic effect between the two different atoms improves the activity of the catalyst in catalyzing oxygen reduction, and also improves the rate of the oxygen reduction reaction.
  • the distance between the iron single atom and the platinum single atom is less than or equal to 0.5 nanometers, and on the conductive substrate, the density of the diatomic pairs is 0.09 pairs/square nanometer (15 pairs/158.24 square nanometers) to 0.18 pairs/square nanometer (21 pairs/112 square nanometers). This shows that the synthesis method of this invention has unique advantages and a higher success rate for synthesizing dimetallic atom pairs.
  • the iron-platinum metal diatomic material of the present invention there are more diatomic sites in the iron-platinum metal diatomic material of the present invention, and there is a synergistic effect between the two different atoms, which improves the activity of the catalyst in catalyzing oxygen reduction, and also improves the rate of the oxygen reduction reaction. At the same time, the selectivity and stability of the material are also greatly improved.
  • the distance between the cobalt single atom and the iron single atom is less than or equal to 0.5 nanometers, and on the conductive substrate, the density of diatomic pairs is 0.10 pairs/square nanometer (29 pairs/280 square nanometers) to 0.16 pairs/square nanometer (44 pairs/280 square nanometers), and the density of atomic pairs is higher.
  • the synthesis method of this article has unique advantages and a higher success rate for synthesizing dimetallic atomic pairs.
  • FIG. 1 is a high-angle annular dark field scanning transmission image of the Fe 1 Co 1 -CNF metal diatomic material in reference 1.
  • FIG. 1 is a high-angle annular dark field scanning transmission image of the Fe 1 Co 1 -CNF metal diatomic material in reference 1.
  • FIG. 2 shows the oxygen reduction polarization curve of the Fe 1 Co 1 -CNF metal diatomic material in reference 1 before and after working at a potential of 0.5 V for 10,000 s.
  • FIG. 3 is a scanning electron microscope image (SEM) of the ZnFeNC metal diatomic material in Example 1.
  • FIG4 is a transmission electron microscope image (TEM) of the ZnFeNC metal diatomic material in Example 1
  • FIG. 5 is an X-ray diffraction pattern (XRD) of the ZnFeNC metal diatomic material in Example 1.
  • FIG. 6 is a high-angle annular dark field scanning transmission image (HADDF-STEM) of the ZnFeNC metal diatomic material in Example 1.
  • FIG. 7 is a peak fitting diagram of the XPS Zn2p spectra of ZnNC, etched ZnNC and ZnFeNC in Example 1.
  • FIG. 8 is a peak fitting diagram of the Fe2p spectrum of XPS of ZnFeNC in Example 1.
  • Figure 9 is a comparison of the linear scanning curves of the ZnFeNC metal diatomic material and each single metal catalyst under the alkaline condition of 0.1 M KOH in Example 1.
  • Figure 10 is a graph showing the cyclic stability of ZnFeNC metal diatomic material and 20% Pt/C under alkaline conditions of 0.1 M KOH in Example 1.
  • FIG. 11 is a scanning electron microscope image (SEM) of the f-CoNiNC-1 metal diatomic material in Example 2.
  • FIG. 12 is a transmission electron microscope image (TEM) of the f-CoNiNC-1 metal diatomic material in Example 2.
  • FIG. 14 is a high-angle annular dark field scanning transmission image (HAADF-STEM) of the f-CoNiNC metal diatomic material in Example 2.
  • Figure 15 is a comparison of the linear scanning curves of f-CoNiNC-1 and f-CoNiNC-2 metal diatomic materials and each single metal catalyst under the alkaline condition of 0.1 M KOH in Example 2.
  • FIG. 16 is a scanning electron microscope image (SEM) of the f-CoCoNC metal diatomic material in Example 3.
  • FIG. 17 is a transmission electron microscope (TEM) image of the f-CoCoNC metal diatomic material in Example 3.
  • FIG. 18 is an X-ray diffraction pattern (XRD) of f-CoCoNC metal diatomic material in Example 3.
  • FIG. 19 is a high-angle annular dark field scanning transmission image (HAADF-STEM) of the f-CoCoNC metal diatomic material in Example 3.
  • Figure 20 is a comparison of the linear scanning curves of the f-CoCoNC metal diatomic material and each single metal catalyst under the alkaline condition of 0.1 M KOH in Example 3.
  • FIG. 21 is a scanning electron microscope image (SEM) of the FeRuNC metal diatomic material in Example 4.
  • FIG. 23 is an X-ray diffraction pattern (XRD) of f-FeRuNC metal diatomic material, FeNC, and etched FeNC in Example 4.
  • XRD X-ray diffraction pattern
  • FIG. 25 is a scanning electron microscope image (SEM) of the NiPtNC metal diatomic material in Example 5.
  • FIG. 26 is a transmission electron microscope (TEM) image of the NiPtNC metal diatomic material in Example 5.
  • Figure 28 is a comparison of the linear scanning curves of NiPtNC metal diatomic materials and various single metal catalysts under alkaline conditions of 0.1 M KOH.
  • FIG. 29 is a scanning electron microscope image (SEM) of the CoIrNC metal diatomic material in Example 6.
  • FIG. 30 is a transmission electron microscope (TEM) image of the CoIrNC metal diatomic material in Example 6.
  • FIG31 is an X-ray diffraction pattern (XRD) of the CoIrNC metal diatomic material in Example 6.
  • Figure 32 is a comparison of the linear scanning curves of CoIrNC metal diatomic materials and various single metal catalysts under alkaline conditions of 0.1 M KOH.
  • Figure 34 is a comparison of the linear scanning curves of MnRuNC metal diatomic materials and various single metal catalysts under alkaline conditions of 0.1 M KOH.
  • FIG. 35 is a scanning electron microscope image (SEM) of the MnPtNC metal diatomic material in Example 8.
  • Figure 38 is a comparison of the linear scanning curves of NiAuNC metal diatomic materials and various single metal catalysts under alkaline conditions of 0.1 M KOH.
  • FIG. 39 is a scanning electron microscope image (SEM) of the NiAgNC metal diatomic material in Example 10.
  • Figure 40 is a comparison of the linear scanning curves of NiAgNC metal diatomic materials and various single metal catalysts under alkaline conditions of 0.1 M KOH.
  • FIG41 is a scanning electron microscope image (SEM) of the FeRuSNC metal diatomic material in Example 11.
  • FIG42 is a transmission electron microscope (TEM) image of the FeRuSNC metal diatomic material in Example 11.
  • FIG. 43 is an X-ray diffraction pattern (XRD) of FeRuSNC metal diatomic material, FeSNC, and etched FeSNC in Example 11.
  • XRD X-ray diffraction pattern
  • Figure 44 is a comparison of the linear scanning curves of the FeRuSNC metal diatomic material and various single metal catalysts under the alkaline condition of 0.1 M KOH in Example 11.
  • FIG. 45 is a comparison of the XPS full spectrum data of f-CoNC and etched f-CoNC materials in Example 2.
  • FIG46 is a scanning electron microscope (SEM) image of FePtNC-1 of Example 12.
  • Figure 47 is a transmission electron microscopy (TEM) of FePtNC-1 of Example 12.
  • Figure 48 is a high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image of FePtNC-1 of Example 12.
  • FIG49 is an X-ray diffraction (XRD) diagram of FePtNC-1, FeNC-1, and etched FeNC-1 of Example 12.
  • Example 50 is a linear sweep polarization curve of oxygen reduction of the FePtNC-1 bimetallic atom catalyst, FeNC-1, etched FeNC-1, and 20 wt % Pt/C materials of Example 12 at 1600 rpm.
  • FIG. 51 shows the four-electron transfer number and hydrogen peroxide yield of the FePtNC-1 bimetallic atom catalyst and 20 wt % Pt/C material of Example 12.
  • FIG. 52 shows the oxygen reduction polarization curves of the FePtNC-1 diatomic material and the 20 wt % Pt/C material of Example 12 before and after working for 10,000 cycles.
  • FIG53 is a scanning electron microscope (SEM) image of the FePtNC-2 diatomic material of Example 13.
  • FIG54 is an X-ray diffraction (XRD) diagram of the FePtNC-2 diatomic material obtained in step 13 of Example 13, the FeNC-2 obtained in step 5, and the etched FeNC-2 obtained in step 9. .
  • XRD X-ray diffraction
  • Figure 55 is a high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image of the FePtNC-2 diatomic material of Example 13.
  • FIG57 is a scanning electron microscope (SEM) image of the FePtNC-3 diatomic material of Example 14.
  • 58 is an X-ray diffraction (XRD) diagram of the FePtNC-3 diatomic material obtained in step 13 of Example 14, the FeNC-3 obtained in step 5, and the etched FeNC-3 obtained in step 9.
  • XRD X-ray diffraction
  • 59 is a linear scan polarization curve of oxygen reduction of the FePtNC-3 diatomic material of implementation 14, the FeNC-3 obtained in step 5, and the etched FeNC-3 obtained in step 9 at 1600 rpm.
  • Figure 60 is a scanning electron microscope (SEM) image of FePtSNC-1 of Example 15.
  • 61 is an X-ray diffraction (XRD) diagram of FePtSNC-1 obtained in step 13 of Example 15, FeSNC-1 obtained in step 5, and etched FeSNC-1 obtained in step 9.
  • XRD X-ray diffraction
  • FIG62 is a diagram of the FePtSNC-1 bimetallic atomic material of Example 15, the FeSNC-1 obtained in step 5, The linear scanning polarization curve of oxygen reduction of etched FeSNC-1 obtained in step 9 at 1600 rpm.
  • Figure 63 is a scanning electron microscope (SEM) image of FePtSNC-2 of Example 16.
  • Figure 64 is an X-ray diffraction (XRD) diagram of FePtSNC-2 obtained in step 13 of Example 16, FeSNC-2 obtained in step 5, and etched FeSNC-2 obtained in step 9.
  • XRD X-ray diffraction
  • Figure 65 is the linear scanning polarization curves of oxygen reduction of the FePtSNC-2 bimetallic atomic material of Example 16, the FeSNC-2 obtained in step 5, and the etched FeSNC-2 obtained in step 9 at 1600 rpm.
  • Figure 66 is a scanning electron microscope (SEM) image of FePtSNC-3 of Example 17.
  • Figure 67 is an X-ray diffraction (XRD) diagram of FePtSNC-3 obtained in step 13 of Example 17, FeSNC-3 obtained in step 5, and etched FeSNC-3 obtained in step 9.
  • XRD X-ray diffraction
  • FIG68 is a linear scanning polarization curve of oxygen reduction of the FePtSNC-3 bimetallic atomic material of Example 17, the FeSNC-3 obtained in step 5, and the etched FeSNC-3 obtained in step 9 at 1600 rpm.
  • FIG69 is a scanning electron microscope (SEM) image of the CoFeNC-1 diatomic material of Example 18.
  • FIG70 is a transmission electron micrograph (TEM) of the CoFeNC-1 diatomic material of Example 18.
  • FIG71 is a high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image of the CoFeNC-1 diatomic material of Example 18.
  • HAADF-STEM high-angle annular dark field scanning transmission electron microscopy
  • FIG. 72 is an X-ray diffraction (XRD) diagram of the CoFeNC-1 diatomic material, CoNC-1, and etched CoNC-1 of Example 18.
  • XRD X-ray diffraction
  • 73 is a linear sweep polarization curve of oxygen reduction of the CoFeNC-1 diatomic material, etched CoNC-1, FeNC, CoNC-1, and 20 wt % Pt/C material of Example 18 at 1600 rpm.
  • FIG. 74 shows the four-electron transfer number and hydrogen peroxide yield of the CoFeNC-1 diatomic material and 20 wt % Pt/C material of Example 18.
  • FIG. 75 is an oxygen reduction polarization curve of the CoFeNC-1 diatomic material and the 20 wt % Pt/C material of Example 18 before and after working for 40,000 seconds.
  • FIG76 is a scanning electron microscope (SEM) image of the CoFeNC-2 diatomic material of Example 19.
  • 77 is an X-ray diffraction (XRD) diagram of the CoFeNC-2 diatomic material obtained in step 14 of Example 19, the CoNC-2 obtained in step 5, and the etched CoNC-2 obtained in step 9.
  • XRD X-ray diffraction
  • FIG78 is a high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image of the CoFeNC-2 diatomic material of Example 19.
  • HAADF-STEM high-angle annular dark field scanning transmission electron microscopy
  • FIG. 79 shows the CoFeNC-2 diatomic material obtained in step 14 of Example 19 and the CoFeNC-2 diatomic material obtained in step 5.
  • FIG80 is a scanning electron microscope (SEM) image of the CoFeNC-3 diatomic material of Example 20.
  • Figure 81 is an X-ray diffraction (XRD) pattern of the CoFeNC-3 diatomic material of Example 20.
  • 82 is a linear scanning polarization curve of oxygen reduction of the CoFeNC-3 diatomic material of Example 20, the CoNC-3 obtained in step 5, and the etched CoNC-3 obtained in step 9 at 1600 rpm.
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • the mixed solution D obtained in step 6 was placed on a stirring table at room temperature and stirred for 10 minutes. During the stirring period, 0.25 mL of 30% (10 mol/L) hydrogen peroxide solution was evenly added dropwise to obtain a uniformly mixed reaction solution E.
  • the concentration of hydrogen peroxide in the reaction solution E was 0.1 mol/L, and the concentration of the zinc single atom nitrogen carbon material ZnNC was 2 mg/mL.
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 200°C, and react for 6 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched zinc single atom nitrogen carbon material (etched ZnNC).
  • the hydroalcohol solution for etching ZnNC obtained in step 10 is evenly added dropwise to the ferric chloride solution obtained in step 11 under vigorous stirring for 2 hours, and the iron ions are adsorbed on the surface of the etched ZnNC material by an immersion method.
  • the ZnNC obtained in step (5), the etched ZnNC obtained in step (9), and the ZnFeNC obtained in step (14) are characterized:
  • FIG. 3 is a scanning electron microscope image (SEM) of the ZnFeNC metal diatomic material in Example 1.
  • Example 4 is a transmission electron microscope (TEM) image of the ZnFeNC metal diatomic material in Example 1. At a scale of 50 nanometers, no nanoparticles of metal zinc or iron appear.
  • TEM transmission electron microscope
  • FIG. 5 is an X-ray diffraction pattern (XRD) of the ZnFeNC metal diatomic material in Example 1.
  • Figures 4 and 5 demonstrate that the diatomic particles do not form metal nanoparticles or alloys.
  • Figure 6 is a high angle annular dark field scanning transmission image (HADDF-STEM) of the ZnFeNC metal diatomic material in Example 1. As shown in Figure 6, the distance between the first single atom Zn and the second single atom Fe is less than 0.5 nm.
  • Table 1 is a statistical table of the distances between 56 pairs of atoms in the ZnFeNC metal diatomic material in Example 1. The statistical results show that the distances between all the atomic pairs are less than 0.5 nanometers. Specifically, the distance between the first single atom Zn and the second single atom Fe is 0.11-0.5 nm.
  • HAADF-STEM high-angle annular dark field scanning transmission image
  • Figure 7 is the peak fitting diagram of the XPS Zn2p spectra of ZnNC, etched ZnNC and ZnFeNC, indicating that Zn is Zn 2+ .
  • Figure 8 is a peak fitting diagram of the Fe2p spectrum of the XPS of ZnFeNC. The peak results show that the material contains iron elements of different oxidation states of Fe2 + and Fe3 + .
  • Figure 9 is a comparison of the linear scanning curves of ZnFeNC metal diatomic materials and various single metal catalysts under 0.1 M KOH.
  • the preparation method of FeNC is as follows: the preparation of FeNC is consistent with the preparation of ZnNC in steps 1-5 of Example 1, except that the zinc salt is replaced with an iron salt, namely, ferric acetylacetonate, with a molar concentration of 0.005 mol/L.
  • the prepared material is FeNC.
  • the ZnNC source is prepared according to the preparation process in Example 1, and the product obtained in step 5.
  • the one-pot preparation method of ZnFeNC is as follows:
  • the etched ZnNC source is prepared according to the preparation process in Example 1, and the product obtained in step 9.
  • the 20% Pt/C material is a Pt/C material with a Pt mass content of 20%, that is, 20wt% Pt/C, which can be purchased on the market.
  • the starting potential of the ZnFeNC metal diatomic material is 1.00V, and its half-wave potential is 0.876V.
  • the starting potential of FeNC is 0.98V, and its half-wave potential is 0.63V.
  • the starting potential of ZnNC is 0.93V, and its half-wave potential is 0.693V.
  • the starting potential of the ZnFeNC one-pot method is 0.98V, and its half-wave potential is 0.68V.
  • the starting potential of 20% Pt/C is 0.99V, and its half-wave potential is 0.84V.
  • Figure 9 proves that the electrocatalytic oxygen reduction activity of the ZnFeNC metal diatomic material is better than that of other materials in Figure 9.
  • Figure 10 shows the cycling stability of ZnFeNC metal diatomic materials and 20% Pt/C under alkaline conditions of 0.1M KOH. After 5000 CV cycles, the half-wave potential of ZnFeNC metal diatomic materials only decayed by 16mV, but the half-wave potential of 20% Pt/C decayed by 51mV. This shows that the cycling stability of ZnFeNC metal diatomic materials is better.
  • the preparation method of CoNiNC metal diatomic material is as follows:
  • the mixed solution D was placed on a constant temperature stirring table and stirred for 10 minutes. During the stirring period, 2.53 mL of 10 mol/L hydrogen peroxide was evenly added dropwise to obtain a uniformly mixed reaction solution E.
  • the concentration of the conductive substrate loaded with the first metal single atom was 5 mg/mL, and the concentration of the peroxide was 1.0 mol/L.
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 200°C, and react for 10 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched cobalt single atom nitrogen carbon material (etched f-CoNC).
  • nickel chloride powder Weigh an appropriate amount of nickel chloride powder and dissolve it in a mixed solution of equal volumes of 12.5 mL of anhydrous ethanol and 12.5 mL of deionized water, and sonicate until dissolved to obtain a nickel chloride solution of 0.75 mg/mL (i.e., 0.006 mol/L) or 1.27 mg/mL (i.e., 0.01 mol/L).
  • the aqueous alcohol solution for etching f-CoNC obtained in step 10 was vigorously stirred for 2 hours, and 25 mL of 0.75 mg Ni /mL or 1.27 mg Ni /mL nickel chloride solution obtained in step 11 was uniformly added dropwise to obtain a mixed solution, and nickel ions were adsorbed on the surface of the etched f-CoNC material by an immersion method.
  • the concentration of the etched f-CoNC material in the mixed solution was 5 mg/mL.
  • step 13 After the mixture obtained in step 12 is stirred for 2 hours, the mixture is filtered and washed, and the obtained solid material is freeze-dried in vacuum overnight.
  • FIG. 11 is a scanning electron microscope image (SEM) of the f-CoNiNC-1 metal diatomic material in Example 2.
  • Example 12 is a transmission electron microscope (TEM) image of the f-CoNiNC metal diatomic material in Example 2. At a scale of 5 nanometers, no nanoparticles of metal cobalt or nickel appear.
  • TEM transmission electron microscope
  • step 12 when the concentration of the nickel chloride solution is 0.75 mg Ni /mL, the product is f-CoNiNC-1.
  • step 12 when the concentration of the nickel chloride solution is 1.27 mg Ni /mL, the product is f-CoNiNC-2.
  • Example 13 is an X-ray diffraction pattern (XRD) of f-CoNiNC-1 metal diatomic material and f-CoNiNC-2 metal diatomic material in Example 2.
  • XRD X-ray diffraction pattern
  • FIG12 and FIG13 demonstrate that there are no nanoparticles of metal cobalt and metal nickel in the f-CoNiNC-1 metal diatomic material and the f-CoNiNC-2 metal diatomic material.
  • FIG. 14 is a high-angle annular dark field scanning transmission image (HAADF-STEM) of the f-CoNiNC-1 metal diatomic material in Example 2.
  • Figure 15 shows the comparison of linear scanning curves of f-CoNiNC-1 and f-CoNiNC-2 metal diatomic materials and each monometallic catalyst under the alkaline condition of 0.1M KOH.
  • the monometallic catalysts are f-CoNC obtained in step 5 and etched f-CoNC obtained in step 9.
  • the half-wave potentials of the metal diatomic materials f-CoNiNC-1 and f-CoNiNC-2 are 0.808 V and 0.810 V, respectively.
  • the half-wave potential of f-CoNC obtained in step 5 is 0.801 V
  • the half-wave potential of the etched f-CoNC obtained in step 9 is 0.793 V.
  • Figure 15 proves that the catalytic performance of f-CoNiNC-1 and f-CoNiNC-2 is better than that of f-CoNC obtained in step 5 and etched f-CoNC obtained in step 9.
  • FIG45 is a comparison of the XPS full spectrum data of f-CoNC and etched f-CoNC materials in Example 2.
  • the C 1s peak intensity of etched f-CoNC is significantly lower than that of f-CoNC, indicating that the etching is mainly at the carbon atom site.
  • the N 1s peak intensity of etched f-CoNC is significantly higher than that of f-CoNC.
  • the N 1s peak intensity shows that more nitrogen atoms are exposed after etching. More nitrogen atoms exposed on the surface of the material can more effectively anchor more second metal atoms. This also lays a good foundation for the synthesis of high-density diatomic atoms.
  • Embodiment 3 is a diagrammatic representation of Embodiment 3
  • the preparation method of f-CoCoNC metal diatomic material is as follows:
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • the obtained solid material C was ground into fine powder, and the fine powder was placed in a porcelain boat. Under the protection of inert gas N2 , the temperature was increased from room temperature at a heating rate of 5°C min -1 , and then carbonized at a constant temperature of 900°C for 6 hours. After the constant temperature was completed, it was naturally cooled to room temperature to obtain cobalt single atom nitrogen carbon material (f-CoNC).
  • f-CoNC cobalt single atom nitrogen carbon material
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 100°C, and react for 3 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched cobalt single atom nitrogen carbon material, which is the etched f-CoNC.
  • the aqueous alcohol solution for etching f-CoNC obtained in step 10 is evenly added dropwise to the cobalt chloride solution obtained in step 11 under vigorous stirring for 2 hours, and nickel ions are adsorbed on the surface of the etched f-CoNC material by an immersion method.
  • step 13 After the mixture obtained in step 12 is stirred for 2 hours, the mixture is filtered and washed, and the obtained solid material is vacuum freeze-dried.
  • FIG. 16 is a scanning electron microscope image (SEM) of the f-CoCoNC metal diatomic material in Example 3.
  • Example 17 is a transmission electron microscope (TEM) image of the f-CoCoNC metal diatomic material in Example 3. At a scale of 50 nanometers, no metal cobalt nanoparticles appear.
  • TEM transmission electron microscope
  • FIG. 17 and FIG. 18 demonstrate that there are no nanoparticles of metallic cobalt in the f-CoCoNC metallic diatomic material.
  • FIG. 19 is a high-angle annular dark field scanning transmission image (HAADF-STEM) of the f-CoCoNC metal diatomic material in Example 3.
  • Figure 20 is a comparison of the linear scanning curves of the f-CoCoNC metal diatomic material and each single metal catalyst (f-CoNC obtained in step 5, etched f-CoNC obtained in step 9) under the alkaline condition of 0.1M KOH.
  • the half-wave potential of the f-CoCoNC metal diatomic material is 0.800V
  • the half-wave potential of the f-CoNC obtained in step 5 is 0.795V
  • the half-wave potential of the etched f-CoNC obtained in step 9 is 0.794V.
  • Embodiment 4 is a diagrammatic representation of Embodiment 4:
  • the preparation method of FeRuNC metal diatomic material is as follows:
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 110°C, and react for 3 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain an etched iron single atom nitrogen carbon material (etched FeNC).
  • the FeNC etching aqueous alcohol solution obtained in step 10 was uniformly added dropwise to the ruthenium chloride solution obtained in step 11 under vigorous stirring for 2 hours to obtain a mixed solution, and ruthenium ions were adsorbed on the surface of the FeNC etching material by an impregnation method.
  • the concentration of the FeNC etching material was 1 mg/mL
  • the concentration of ruthenium chloride was 0.0240 mol/L.
  • step 13 After the mixed solution obtained in step 12 is stirred for 2 hours, the mixed solution is filtered and washed, and the obtained solid material is vacuum freeze-dried.
  • FIG. 21 is a scanning electron microscope image (SEM) of the FeRuNC metal diatomic material in Example 4.
  • Example 22 is a transmission electron microscope (TEM) image of the FeRuNC metal diatomic material in Example 4. At a scale of 50 nanometers, no nanoparticles of metallic iron or ruthenium appear.
  • TEM transmission electron microscope
  • FIG. 23 is an X-ray diffraction pattern (XRD) of the FeRuNC metal diatomic material, the FeNC obtained in step 5, and the etched FeNC obtained in step 9 in Example 4.
  • XRD X-ray diffraction pattern
  • FIG24 is a comparison of the linear scanning curves of the FeRuNC metal diatomic material and each monometallic catalyst (FeNC obtained in step 5, etched FeNC obtained in step 9) under the alkaline condition of 0.1 M KOH.
  • the half-wave potential of the FeRuNC metal diatomic material is 0.886 V.
  • the half-wave potential of the FeNC obtained in step 5 is 0.853 V, and the half-wave potential of the etched FeNC obtained in step 9 is 0.842 V. This shows that the electrocatalytic oxygen reduction activity of the FeRuNC metal diatomic material is better than that of the FeNC obtained in step 5 and the etched FeNC obtained in step 9.
  • Embodiment 5 is a diagrammatic representation of Embodiment 5:
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 200°C, and react for 3 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain an etched iron single atom nitrogen carbon material (etched NiNC).
  • the aqueous alcohol solution for etching NiNC obtained in step 10 is evenly added dropwise to the chloroplatinic acid solution obtained in step 11 under vigorous stirring for 2 hours, and ruthenium ions are adsorbed on the surface of the etched NiNC material by an immersion method.
  • step 13 After stirring the mixed solution obtained in step 12 for 2 hours, the mixed solution is filtered and washed, and the obtained solid material is vacuum freeze-dried.
  • FIG. 25 is a scanning electron microscope image (SEM) of the NiPtNC metal diatomic material in Example 5.
  • Example 26 is a transmission electron microscope (TEM) image of the NiPtNC metal diatomic material in Example 5. At a scale of 50 nanometers, no nanoparticles of metal nickel or platinum appear.
  • TEM transmission electron microscope
  • FIG28 is a comparison of the linear scanning curves of the NiPtNC metal diatomic material and each single metal catalyst (NiNC material obtained in step 5, etched NiPtNC material obtained in step 9) under the alkaline condition of 0.1 M KOH.
  • the half-wave potential of the NiPtNC metal diatomic material is 0.812 V.
  • the half-wave potential of the NiNC material obtained in step 5 is 0.707 V, and the half-wave potential of the etched NiPtNC material obtained in step 9 is 0.717 V. This shows that the oxygen reduction catalytic activity of the NiPtNC metal diatomic material under alkaline conditions is better than that of the NiNC material obtained in step 5 and the etched NiPtNC material obtained in step 9.
  • Embodiment 6 is a diagrammatic representation of Embodiment 6
  • the preparation method of CoIrNC metal diatomic material is as follows:
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 150°C, and react for 3 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched cobalt single atom nitrogen carbon material (etched CoNC).
  • the aqueous alcohol solution for etching CoNC obtained in step 10 is evenly added dropwise to the chloroiridic acid solution obtained in step 11 under vigorous stirring for 2 hours, and ruthenium ions are adsorbed on the surface of the etched CoNC material by an immersion method.
  • step 13 After stirring the mixed solution obtained in step 12 for 2 hours, the mixed solution is filtered and washed, and the obtained solid material is vacuum freeze-dried.
  • FIG. 29 is a scanning electron microscope image (SEM) of the CoIrNC metal diatomic material in Example 6.
  • Example 30 is a transmission electron microscope (TEM) image of the CoIrNC metal diatomic material in Example 6. At a scale of 50 nanometers, no nanoparticles of metal cobalt or iridium appear.
  • TEM transmission electron microscope
  • FIG. 31 is an X-ray diffraction pattern (XRD) of the CoIrNC metal diatomic material, the CoNC material obtained in step 5, and the etched CoNC material obtained in step 9 in Example 6.
  • XRD X-ray diffraction pattern
  • CoIrNC metal diatomic material does not contain nanoparticles of metal cobalt and metal iridium.
  • FIG 32 Comparison of linear scanning curves of CoIrNC metal diatomic material and each single metal catalyst (CoNC material obtained in step 5, etched CoNC material obtained in step 9) under alkaline conditions of 0.1M KOH.
  • the half-wave potential of CoIrNC metal diatomic material is 0.885V, which is much higher than the half-wave potential of CoNC material (half-wave potential is 0.801V) and etched CoNC material (half-wave potential is 0.793V). This shows that the electrocatalytic oxygen reduction activity of CoIrNC metal diatomic material is better than that of CoNC material obtained in step 5 and etched CoNC material obtained in step 9.
  • Embodiment 7 is a diagrammatic representation of Embodiment 7:
  • step 14 MnRuNC metal diatomic material can be obtained.
  • step 5 can obtain manganese single atom nitrogen carbon material, namely MnNC.
  • step 9 can obtain the etched MnNC material after etching.
  • FIG. 33 is a scanning electron microscope (SEM) image of the MnRuNC metal diatomic material.
  • FIG34 is a comparison of the linear scanning curves of MnRuNC metal diatomic material, MnNC and etched MnNC under the alkaline condition of 0.1M KOH.
  • the half-wave potential of MnRuNC metal diatomic material is 0.788 V, which is higher than the half-wave potential of MnNC material (half-wave potential is 0.757 V) and etched MnNC material (half-wave potential is 0.723 V). This shows that the electrocatalytic oxygen reduction activity of MnRuNC metal diatomic material is better than that of MnNC material and etched MnNC material.
  • Embodiment 8 is a diagrammatic representation of Embodiment 8
  • the preparation method of MnPtNC metal diatomic material is as follows:
  • step 5 can obtain manganese single atom nitrogen carbon material, namely MnNC.
  • step 9 can obtain the etched MnNC material after etching.
  • FIG. 35 is a scanning electron microscope (SEM) image of MnPtNC metal diatomic material.
  • Figure 36 shows the comparison of linear scanning curves of MnPtNC metal diatomic material, MnNC and etched MnNC under alkaline conditions of 0.1M KOH.
  • the half-wave potential of MnPtNC metal diatomic material is 0.844V, which is higher than the half-wave potential of MnNC material (half-wave potential is 0.774V) and etched MnNC material (half-wave potential is 0.734V). This shows that the electrocatalytic oxygen reduction activity of MnPtNC metal diatomic material is better than that of MnNC material and etched MnNC material.
  • Embodiment 9 is a diagrammatic representation of Embodiment 9:
  • NiAuNC metal diatomic material The preparation method of NiAuNC metal diatomic material is as follows:
  • step 5 can obtain nickel single atom nitrogen carbon material, namely NiNC.
  • Step 9 can obtain etched NiNC material after etching.
  • FIG. 37 is a scanning electron microscope (SEM) image of NiAuNC metal diatomic material.
  • Figure 38 shows the comparison of linear scanning curves of NiAuNC metal diatomic material, NiNC and etched NiNC under alkaline conditions of 0.1M KOH.
  • the half-wave potential of NiAuNC metal diatomic material is 0.786V, which is higher than the half-wave potential of NiNC material (half-wave potential is 0.707V) and etched NiNC material (half-wave potential is 0.717V). This shows that the electrocatalytic oxygen reduction activity of NiAuNC metal diatomic material is better than that of NiNC material and etched NiNC material.
  • Embodiment 10 is a diagrammatic representation of Embodiment 10:
  • NiAgNC metal diatomic material The preparation method of NiAgNC metal diatomic material is as follows:
  • step 5 can obtain nickel single atom nitrogen carbon material, namely NiNC.
  • Step 9 can obtain etched NiNC material after etching.
  • FIG. 39 is a scanning electron microscope (SEM) image of NiAgNC metal diatomic material.
  • Figure 40 shows the comparison of linear scanning curves of NiAuNC metal diatomic material, NiNC and etched NiNC under alkaline conditions of 0.1M KOH.
  • the half-wave potential of NiAgNC metal diatomic material is 0.807V, which is higher than the half-wave potential of NiNC material (half-wave potential is 0.707V) and etched NiNC material (half-wave potential is 0.717V). This shows that the electrocatalytic oxygen reduction activity of NiAgNC metal diatomic material is better than that of NiNC material and etched NiNC material.
  • Embodiment 11 is a diagrammatic representation of Embodiment 11:
  • the preparation method of FeRuSNC metal diatomic material is as follows:
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • the obtained solid material C was ground into fine powder, and the fine powder was placed in a porcelain boat. Under the protection of inert gas N2, the temperature was increased from room temperature at a heating rate of 5°C min -1 , and then carbonized at a constant temperature of 900°C for 2 hours. After the constant temperature was completed, it was naturally cooled to room temperature to obtain iron single-atom sulfur nitrogen carbon material (FeSNC).
  • FeSNC iron single-atom sulfur nitrogen carbon material
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 110°C, and react for 3 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched iron single atom nitrogen carbon material (etched FeSNC).
  • the FeSNC etching aqueous alcohol solution obtained in step 10 was uniformly added to the ruthenium chloride solution obtained in step 11 under vigorous stirring for 2 hours to obtain a mixed solution, and ruthenium ions were adsorbed on the surface of the FeSNC material by an immersion method.
  • the concentration of the FeSNC material was 1 mg/mL
  • the concentration of the ruthenium chloride solution was 0.024 mol/L.
  • step 13 After stirring the mixed solution obtained in step 12 for 2 hours, the mixed solution is filtered and washed, and the obtained solid material is vacuum freeze-dried.
  • FIG41 is a scanning electron microscope image (SEM) of the FeRuSNC metal diatomic material in Example 11.
  • Figure 42 is a transmission electron microscope (TEM) image of the FeRuSNC metal diatomic material in Example 11. At a scale of 50 nanometers, no nanoparticles of metallic iron or ruthenium appear.
  • TEM transmission electron microscope
  • XRD 43 is an X-ray diffraction pattern (XRD) of the FeRuSNC metal diatomic material, the FeNC obtained in step 5, and the etched FeSNC obtained in step 9 in Example 11.
  • Figures 42 and 43 demonstrate that there are no nanostructured Fe and Ru metals in the FeRuSNC metal diatomic material. Particles.
  • FIG44 is a comparison of the linear scanning curves of the FeRuSNC metal diatomic material and each monometallic catalyst (FeSNC obtained in step 5, etched FeSNC obtained in step 9) under the alkaline condition of 0.1 M KOH.
  • the half-wave potential of the FeRuSNC metal diatomic material is 0.878 V.
  • the half-wave potential of the FeSNC obtained in step 5 is 0.833 V, and the half-wave potential of the etched FeSNC obtained in step 9 is 0.813 V. This shows that the electrocatalytic oxygen reduction activity of the FeRuSNC metal diatomic material is better than that of the FeSNC obtained in step 5 and the etched FeSNC obtained in step 9.
  • the preparation method of the iron-platinum-nitrogen-carbon material comprises the following steps:
  • the uniform dark red solution obtained is the hydrothermal reaction mother solution A; the molar ratio of the iron salt to the zinc salt is 1:10, and the above-mentioned iron salt is ferric acetylacetonate, with a molar number of 0.005 mol/L.
  • the zinc salt is anhydrous zinc chloride, with a molar number of 0.1 mol/L.
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • reaction solution E Place the mixed solution D on a constant temperature stirring table and stir for 10 minutes. During the stirring period, 0.30 mL of a 30% hydrogen peroxide solution is evenly added dropwise to obtain a uniformly mixed reaction solution E.
  • the concentration of hydrogen peroxide is 0.1 mol/L
  • the concentration of the iron single atom nitrogen-carbon material is 2 mg/mL.
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 110°C, and react for 3 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched iron single atom nitrogen carbon material (etched FeNC-1).
  • the concentration of chloroplatinic acid is 0.0009 mol/L
  • FIG46 is a scanning electron microscope (SEM) image of FePtNC.
  • FIG. 47 is a transmission electron microscopy (TEM) image of FePtNCs.
  • TEM Transmission electron microscopy
  • FIG48 is a high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image of FePtNC.
  • Figure 48 confirms the diatomic FePtNC.
  • the bright spots in the image represent metal atoms, most of which appear in the form of two FePt atom pairs in the image, proving that the material is diatomic FePtNC.
  • the distance between the two atoms was measured by direct measurement analysis method, and the distance statistics between the two atoms are shown in Table 1 below.
  • Table 1 above proves that the distance between all diatoms is less than or equal to 0.5 nm, that is, the distance between a single iron atom and a single platinum atom is less than or equal to 0.5 nanometers, specifically 0.14 to 0.5 nm.
  • Figure 1d of reference 2 is a high-angle annular dark field scanning transmission image of the PtFeNC bimetallic atom catalyst.
  • Figure 1d in reference 2 under the scale of 5 nanometers, there are 15 pairs of bimetallic atoms at 1126.388 square nanometers, and the number of atomic pairs is relatively small.
  • Figure 48 proves that the material of the present invention has more diatomic sites. This proves that: on the conductive substrate of nitrogen-carbon material, the success probability of diatoms is greater than that of bimetallic atoms prepared by one-pot hydrothermal method.
  • the area of the picture is obtained by the inventor through calculation and conversion based on the scale in the picture and the actual size of the picture.
  • FIG49 is an X-ray diffraction (XRD) pattern of FePtNC-1, FeNC-1 and etched FeNC-1.
  • the X-ray diffraction (XRD) of Figure 49 shows that the FePtNC-1 diatomic material only exhibits There are two diffraction peaks, which are the (002) and (100) planes of graphite carbon, and no diffraction peaks of metallic iron and metallic platinum nanoparticles appear, so there are no metal particles in the synthesized series of materials. Iron and platinum are both in a single atomic dispersion state.
  • the performance of the FePtNC-1 obtained above was tested using a CHI three-electrode system and a linear sweep saturation voltage (LSV) test was performed at an O 2- saturated 0.1 M KOH and a rotation speed of 1600 rpm.
  • LSV linear sweep saturation voltage
  • FIG50 is a linear scan polarization curve of oxygen reduction of FePtNC-1 bimetallic atom catalyst, FeNC-1 and etched FeNC-1, 20wt% Pt/C material at 1600rmp
  • Figure 50 proves that under the alkaline condition of 0.1M KOH, the half-wave potential of FePtNC-1 diatoms is 0.905V, which is much better than single-atom-level FeNC-1, etched FeNC-1 and FeNC-1 (the half-wave potential of FeNC-1 is 0.853V, and the half-wave potential of etched FeNC is 0.842V).
  • the half-wave potential of FePtNC-1 diatomic is 33 mV higher than that of 20 wt % Pt/C (0.872 V).
  • Figure 50 proves that adding a second metal species to form a diatomic catalyst can greatly enhance the oxygen reduction performance of the single atom catalyst and accelerate the rate of the oxygen reduction reaction.
  • the 20wt% Pt/C material is a Pt/C material with a Pt content of 20% by mass, which can be purchased on the market.
  • the etched FeNC-1 source is prepared according to the preparation process in Example 1, and the product is obtained in step 9.
  • the FeNC-1 source is prepared according to the preparation process in Example 1, and the product obtained in step 5.
  • Figure 51 shows the four-electron transfer number and hydrogen peroxide yield of the FePt bimetallic atom catalyst material.
  • Figure 51 proves that the electron transfer number of FePtNC-1 diatoms is 4, which is very close to the 4-electron transfer number calculated by experimental data. At the same time, the yield of hydrogen peroxide in a wide potential range is less than 1%, indicating that the 4-electron selectivity of FePtNC-1 diatoms is high.
  • 20wt% Pt/C material is used as a comparative material and compared with FePtNC-1 to show that the electrocatalytic oxygen reduction performance of FePtNC-1 diatoms is excellent.
  • FIG. 52 shows the oxygen reduction polarization curves of the FePtNC-1 diatomic catalyst and 20wt% Pt/C material before and after 10,000 cycles.
  • Figure 52 shows that after 10,000 cycles, the half-wave potential of the FePtNC-1 diatomic catalyst only shifted negatively by 8mV, and the activity decay was negligible. However, the half-wave potential of 20wt% Pt/C showed obvious decay.
  • the preparation method of the iron-platinum-nitrogen-carbon material comprises the following steps:
  • the uniform dark red solution obtained is the hydrothermal reaction mother solution A; the molar ratio of the iron salt to the zinc salt is 1:4, and the above-mentioned iron salt is anhydrous ferric chloride with a molar number of 0.005 mol/L.
  • the zinc salt is anhydrous zinc chloride with a molar number of 0.2 mol/L.
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 150°C, and react for 5 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched iron single atom nitrogen carbon material (etched FeNC-2).
  • FIG53 is a scanning electron microscope (SEM) image of the FePtNC-2 diatomic material of Example 13.
  • Figure 54 is an X-ray diffraction (XRD) pattern of FePtNC-2 obtained in step 13 of Example 13, FeNC-2 obtained in step 9, and etched FeNC-2 obtained in step 5. As shown in Figure 54, there are only two carbon peaks, indicating that there are no metal nanoparticles in FeNC-2, etched FeNC-2, and FePtNC-2.
  • XRD X-ray diffraction
  • FIG55 is a high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) image of the FePtNC-2 diatomic material of Example 13.
  • HAADF-STEM high-angle annular dark field scanning transmission electron microscope
  • Figure 56 is a linear scanning polarization curve of oxygen reduction of the FePtNC-2 diatomic material of Example 13, the FeNC-2 obtained in step 5, and the etched FeNC-2 obtained in step 9 under the alkaline condition of 0.1M KOH saturated with O2 and a rotation speed of 1600rmp.
  • the half-wave potential of the FePtNC-2 diatomic material is 0.887V
  • the half-wave potential of FeNC-2 is 0.860V
  • the half-wave potential of the etched FeNC-2 is 0.812V.
  • Comparative analysis shows that the half-wave potential of FePtNC-2 is the largest, indicating that its electrocatalytic oxygen reduction activity is the best. This shows that in the electrocatalytic oxygen reduction reaction, iron single atoms and platinum single atoms have a synergistic effect, and the catalytic activity of iron-platinum diatomic atoms is higher than that of iron single atoms.
  • the preparation method of the iron-platinum-nitrogen-carbon material comprises the following steps:
  • the uniform dark red solution obtained by fully dissolving in formamide is the hydrothermal reaction mother solution A; the molar ratio of the iron salt to the zinc salt is 1:20, the iron salt is anhydrous ferric chloride, the molar number is 0.005 mol/L, and the zinc salt is anhydrous zinc chloride, the molar number is 0.2 mol/L.
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • reaction solution E transfers to a high pressure reactor, place it in an oven at 200°C, and react for 8 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched iron single atom nitrogen carbon material (etched FeNC-3).
  • FIG57 is a scanning electron microscope (SEM) image of the FePtNC-3 diatomic material of Example 14.
  • Figure 58 is an X-ray diffraction (XRD) diagram of FePtNC-3 obtained in step 13 of Example 14, FeNC-3 obtained in step 9, and etched FeNC-3 obtained in step 5. As shown in Figure 58, there are only two carbon peaks, indicating that there are no metal nanoparticles in FeNC-3, etched FeNC-3 and FePtNC-3.
  • XRD X-ray diffraction
  • FIG59 is a linear scanning polarization curve of oxygen reduction of the FePtNC-3 diatomic material of implementation 14, the FeNC-3 obtained in step 5, and the etched FeNC-3 obtained in step 9 under the alkaline condition of 0.1M KOH saturated with O2 and a rotation speed of 1600 rpm.
  • the half-wave potential of the FePtNC-3 diatomic material is 0.884 V
  • the half-wave potential of FeNC-3 is 0.855 V
  • the half-wave potential of the etched FeNC-3 is 0.837 V.
  • Comparative analysis shows that the half-wave potential of FePtNC-3 is the largest, indicating that its electrocatalytic oxygen reduction activity is the best. This shows that in the electrocatalytic oxygen reduction reaction, iron single atoms and platinum single atoms have a synergistic effect, and the catalytic activity of iron-platinum diatomic atoms is higher than that of iron single atoms.
  • the preparation method of platinum iron sulfur nitrogen carbon material comprises the following steps:
  • the uniform dark red solution obtained is the hydrothermal reaction mother solution A; the molar ratio of iron salt, zinc salt and sulfur source is 1:10:2, the iron salt is anhydrous ferric chloride, and the molar number is 0.005 mol/L.
  • the zinc salt is anhydrous zinc chloride, and the molar number is 0.1 mol/L.
  • the sulfur source is thiourea, and the molar number is 0.01 mol/L
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • the obtained solid material C was ground into fine powder, and the fine powder was placed in a porcelain boat. Under the protection of inert gas N2 , the temperature was increased from room temperature at a heating rate of 5°C min -1 , and then carbonized at a constant temperature of 900°C for 2 hours. After the constant temperature was completed, it was naturally cooled to room temperature to obtain iron single atom nitrogen carbon material (FeSNC-1).
  • reaction solution E Place the mixed solution D on a constant temperature stirring table and stir for 10 minutes. During the stirring period, 0.30 mL of a 30% hydrogen peroxide solution is evenly added dropwise to obtain a uniformly mixed reaction solution E.
  • the concentration of hydrogen peroxide is 0.1 mol/L
  • the concentration of the iron single atom nitrogen-carbon material is 2 mg/mL.
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 110°C, and react for 3 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched iron single atom nitrogen carbon material (etched FeSNC-1).
  • the mixture was transferred to a constant temperature stirring table, and 17.5 ⁇ L of chloroplatinic acid solution (1.05 g/ml) was evenly added dropwise to obtain a mixed solution, which was vigorously stirred for 2 hours at room temperature, and platinum ions were adsorbed on the surface of the etched FeSNC-1 material by an immersion method.
  • the concentration of etched FeNC-1 was 1 mg/mL
  • the concentration of chloroplatinic acid was 0.0009 mol/L.
  • FIG60 is a scanning electron microscope (SEM) image of FePtSNC-1.
  • FIG61 is an X-ray diffraction (XRD) pattern of FePtSNC-1, FeSNC-1 and etched FeSNC-1.
  • the preparation method of platinum iron sulfur nitrogen carbon material comprises the following steps:
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • the obtained solid material C was ground into fine powder, and the fine powder was placed in a porcelain boat. Under the protection of inert gas N2 , the temperature was increased from room temperature at a heating rate of 5°C min -1 , and then carbonized at a constant temperature of 800°C for 4 hours. After the constant temperature was completed, it was naturally cooled to room temperature to obtain iron single atom nitrogen carbon material (FeSNC-2).
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 150°C, and react for 5 hours.
  • Figure 63 is a scanning electron microscope (SEM) image of the FePtSNC-2 diatomic material of Example 16.
  • Figure 64 is an X-ray diffraction (XRD) pattern of FePtNC-2 obtained in step 13 of Example 16, FeSNC-2 obtained in step 9, and etched FeSNC-2 obtained in step 2. As shown in Figure 64, there are only two carbon peaks, indicating that there are no metal nanoparticles in FeSNC-5, etched FeNC-2, and FePtNC-2.
  • XRD X-ray diffraction
  • Figure 65 is a linear scanning polarization curve of oxygen reduction of the FePtSNC-2 bimetallic atomic material of Example 16, the FeSNC-2 obtained in step 5, and the etched FeSNC-2 obtained in step 9 under the alkaline condition of 0.1M KOH saturated with O2 and a rotation speed of 1600rmp.
  • the half-wave potential of the FePtSNC-2 bimetallic atomic material is 0.897V
  • the half-wave potential of FeSNC-2 is 0.855V
  • the half-wave potential of the etched FeSNC-2 is 0.844V.
  • Comparative analysis shows that the half-wave potential of FePtSNC-2 is the largest, indicating that its electrocatalytic oxygen reduction activity is the best. This shows that in the electrocatalytic oxygen reduction reaction, iron single atoms and platinum single atoms have a synergistic effect, and the catalytic activity of iron-platinum biatoms is higher than that of iron single atoms.
  • the preparation method of platinum iron sulfur nitrogen carbon material comprises the following steps:
  • the uniform dark red solution obtained is the hydrothermal reaction mother solution A; the molar ratio of iron salt, zinc salt and sulfur source is 1:20:2, the iron salt is anhydrous ferric chloride, and the molar number is 0.005 mol/L.
  • the zinc salt is anhydrous zinc chloride, and the molar number is 0.2 mol/L.
  • the sulfur source is thiourea, and the molar number is 0.01 mol/L
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • the obtained solid material C was ground into fine powder, and the fine powder was placed in a porcelain boat. Under the protection of inert gas N2 , the temperature was increased from room temperature at a heating rate of 5°C min -1 , and then carbonized at a constant temperature of 1100°C for 6 hours. After the constant temperature was completed, it was naturally cooled to room temperature to obtain iron single atom nitrogen carbon material (FeSNC-3).
  • reaction solution E transfers to a high pressure reactor, place it in an oven at 200°C, and react for 8 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched iron single atom nitrogen carbon material (etched FeSNC-3).
  • Figure 66 is a scanning electron microscope (SEM) image of the FePtSNC-3 diatomic material of Example 17.
  • Figure 67 is an X-ray diffraction (XRD) diagram of FePtSNC-3 obtained in step 13 of Example 17, FeSNC-3 obtained in step 9, and etched FeSNC-3 obtained in step 6. As shown in Figure 67, there are only two carbon peaks, indicating that there are no metal nanoparticles in FeSNC-3, etched FeSNC-3 and FePtSNC-3.
  • XRD X-ray diffraction
  • Figure 68 is a linear scanning polarization curve of oxygen reduction of the FePtSNC-3 bimetallic atomic material of Example 17, the FeSNC-3 obtained in step 5, and the etched FeSNC-3 obtained in step 9 under the alkaline condition of 0.1M KOH saturated with O2 and a rotation speed of 1600rmp.
  • the half-wave potential of the FePtSNC-3 bimetallic atomic material is 0.861V
  • the half-wave potential of FeSNC-3 is 0.833V
  • the half-wave potential of the etched FeSNC-3 is 0.824V.
  • Comparative analysis shows that the half-wave potential of FePtSNC-3 is the largest, indicating that its electrocatalytic oxygen reduction activity is the best. This shows that in the electrocatalytic oxygen reduction reaction, iron single atoms and platinum single atoms have a synergistic effect, and the catalytic activity of iron-platinum biatoms is higher than that of iron single atoms.
  • the preparation method of the cobalt-iron metal diatomic material comprises the following steps:
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 180°C, and react for 6 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched cobalt single atom nitrogen-carbon material (etched CoNC-1).
  • the aqueous alcohol solution for etching CoNC-1 was vigorously stirred for 2 hours, and then the ferric chloride solution was evenly added dropwise, and the iron ions were adsorbed on the surface of the etched CoNC-1 material by an immersion method.
  • Figure 69 is a scanning electron microscope (SEM) image of CoFeNC-1.
  • Figure 70 is a transmission electron microscopy (TEM) of CoFeNC-1.
  • TEM Transmission electron microscopy
  • Figure 71 is a high-angle annular dark field scanning transmission electron microscopy (HAADF-STEM) image of CoFeNC-1.
  • Figure 71 confirms the diatomic nature of CoFeNC-1.
  • the bright spots in the image represent metal atoms, most of which appear in the form of two cobalt-iron atom pairs, proving that the material is a cobalt-iron metal diatomic material.
  • the distance between the two atoms was measured by direct measurement analysis method, and the distance statistics between the two atoms are shown in Table 1 below.
  • Table 1 above proves that the distance between all diatoms is less than or equal to 0.5 nm, that is, the distance between a single cobalt atom and a single iron atom is less than or equal to 0.5 nanometers, specifically 0.15 to 0.5 nm.
  • FIG1 is a high-angle annular dark field scanning transmission image of the Fe 1 Co 1 -CNF bimetallic atom catalyst in reference 1. As shown in FIG1, under the scale of 2 nanometers, there are 9 pairs of bimetallic atoms under 156.11 square nanometers, and the number of atomic pairs is relatively small. FIG71 is compared with FIG1, which proves that the material of the present invention has more diatomic sites. This proves that: on the conductive substrate of nitrogen-carbon material, the success probability of diatoms is greater than that of bimetallic atoms prepared by one-pot hydrothermal method.
  • FIG. 72 is an X-ray diffraction (XRD) pattern of CoFeNC-1, CoNC-1 and etched CoNC-1.
  • the X-ray diffraction (XRD) in Figure 72 shows that the CoFeNC-1 diatomic material only exhibits two diffraction peaks at 25° and 43°, which are the (002) and (100) planes of graphite carbon, respectively, and there are no diffraction peaks of metallic cobalt and metallic iron nanoparticles. Therefore, the synthesized series of materials do not contain metal particles, and cobalt and iron are both in a single-atom dispersed state.
  • the X-ray diffraction (XRD) patterns of CoNC-1 and etched CoNC-1 in FIG72 have only two carbon peaks, indicating that there are no metallic cobalt nanoparticles in CoNC-1 and etched CoNC-1, and cobalt is in a single-atom dispersed state.
  • Figure 73 shows the linear scan polarization curves of oxygen reduction of CoFeNC-1 diatomic material, etched CoNC-1, FeNC, CoNC-1, and 20wt% Pt/C material at 1600rmp.
  • Figure 73 proves that: in 0.1M KOH Under the conditions of 100% mol/l, the half-wave potential of the CoFeNC-1 diatomic material is 0.897V, which is much better than the single-atom-level CoNC-1, etched CoNC-1 and FeNC (the half-wave potential of etched CoNC-1 is 0.793V, the half-wave potential of CoNC-1 is 0.801V, and the half-wave potential of FeNC is 0.864V).
  • the half-wave potential of the CoFeNC-1 diatomic material is 25mV higher than the half-wave potential of 20wt% Pt/C (0.872V).
  • Figure 73 proves that: Therefore, adding a second metal species to form a diatomic catalyst can greatly improve the oxygen reduction performance of the single-atom catalyst and accelerate the oxygen reduction reaction rate.
  • the 20wt% Pt/C material is a Pt/C material with a Pt mass content of 20%, which can be purchased on the market.
  • the etched CoNC-1 source is the product obtained in step 9 prepared according to the preparation process in Example 18.
  • the CoNC-1 source is the product obtained in step 5 prepared according to the preparation process in Example 18.
  • the preparation method of FeNC is as follows: the preparation of FeNC is consistent with the preparation of CoNC-1 in steps 1-5 in Example 18, except that the cobalt salt is replaced with an iron salt, namely iron acetylacetonate, with a molar concentration of 0.005 mol/L.
  • the prepared material is FeNC.
  • Figure 74 shows the four-electron transfer number and hydrogen peroxide yield of CoFeNC-1 diatomic material and 20wt% Pt/C material.
  • Figure 74 proves that: calculated by experimental data, the electron transfer number of CoFeNC-1 diatomic material is 3.99, which is very close to the four-electron transfer number. At the same time, the yield of hydrogen peroxide in a wide potential range is less than 1%, indicating that the four-electron selectivity of CoFeNC-1 diatomic material is high.
  • 20wt% Pt/C material is used as a comparative material and compared with CoFeNC-1 diatomic material to show that CoFeNC-1 diatomic material has excellent electrocatalytic oxygen reduction performance.
  • Figure 75 shows the oxygen reduction polarization curves of the CoFeNC-1 diatomic material and the 20wt% Pt/C material before and after working for 40,000 seconds.
  • Figure 75 shows that after 40,000 seconds of cycling, the half-wave potential of the CoFeNC-1 diatomic material only shifted negatively by 3mV (after an average of about 10,000 seconds of cycling, the half-wave potential only shifted negatively by 0.75mV), and the activity decay was negligible. However, the half-wave potential of 20wt% Pt/C showed obvious decay.
  • Figure 2 shows the oxygen reduction polarization curves of the Fe 1 Co 1 -CNF bimetallic atom catalyst in reference 1 before and after working for 10,000 seconds at a potential of 0.5 V.
  • the cycle stability of the Fe 1 Co 1 -CNF bimetallic atom catalyst is poor.
  • the half-wave potential of the Fe 1 Co 1 -CNF bimetallic atom catalyst shifted negatively by 2 mV (Note: the smaller the half-wave potential negative shift value, the longer the cycle time, and the higher the cycle stability).
  • the preparation method of the cobalt-iron metal diatomic material comprises the following steps:
  • the obtained clear pink solution is the hydrothermal reaction mother solution A; the molar ratio of the cobalt salt to the zinc salt is 1:4, the above cobalt salt is cobalt nitrate, and the molar number is 0.025 mol/L.
  • the zinc salt is anhydrous zinc chloride, and the molar number is 0.1 mol/L.
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • reaction solution E Transfer the reaction solution E to a high pressure reactor, place it in an oven at 150°C, and react for 6 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain the etched cobalt single atom nitrogen-carbon material (etched CoNC-2).
  • the aqueous alcohol solution for etching CoNC-2 was vigorously stirred for 2 hours, and then the ferric chloride solution was evenly added dropwise, and the iron ions were adsorbed on the surface of the etched CoNC-2 material by an immersion method.
  • FIG76 is a scanning electron microscope (SEM) image of the CoFeNC-2 diatomic material of Example 19.
  • Figure 77 is an X-ray diffraction (XRD) pattern of CoFeNC-2 obtained in step 14 of Example 19, CoNC-2 obtained in step 9, and etched CoNC-2 obtained in step 5.
  • Figure 11 shows only two carbon peaks, indicating that there are no metal nanoparticles in CoNC-2, etched CoNC-2, and CoFeNC-2.
  • FIG78 is a high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) image of the CoFeNC-2 diatomic material of Example 19.
  • HAADF-STEM high-angle annular dark field scanning transmission electron microscope
  • Figure 79 shows the linear scanning polarization curves of oxygen reduction of the CoFeNC-2 diatomic material obtained in step 14 of Example 19, the CoNC-2 obtained in step 5, the etched CoNC-2, FeNC-2 and 20wt% Pt/C materials obtained in step 9 under the alkaline conditions of 0.1M KOH saturated with O2 and a rotation speed of 1600 rpm.
  • the preparation method of FeNC-2 is as follows: the preparation of FeNC-2 is consistent with the preparation of CoNC-2 in steps 1-5 in Example 19, except that the cobalt salt is replaced with an iron salt, namely iron acetylacetonate, with a molar concentration of 0.005 mol/L.
  • the prepared material is FeNC-2.
  • the 20wt% Pt/C material is a Pt/C material with a Pt mass content of 20%, which can be purchased on the market.
  • the half-wave potential of the CoFeNC-2 diatomic material is 0.885 V, while the half-wave potential of CoNC-2 is 0.802 V and the half-wave potential of FeNC-2 is 0.846 V.
  • the half-wave potential of the CoFeNC-2 diatomic material is the largest, and is 13 mV higher than the half-wave potential of 20 wt% Pt/C (the half-wave potential of 20 wt% Pt/C is 0.872 V), indicating that the CoFeNC-2 diatomic material has the best electrocatalytic oxygen reduction performance.
  • the preparation method of the cobalt-iron metal diatomic material comprises the following steps:
  • the sealed reactor is naturally cooled to room temperature, and then the reactor is opened and the reaction liquid is filtered, and then washed twice with deionized water and anhydrous ethanol to obtain a solid material B without formamide residue.
  • reaction solution E transfers to a high pressure reactor, place it in an oven at 200°C, and react for 8 hours.
  • the solid material obtained in the high-pressure reactor is filtered, washed three times with deionized water, and placed in a vacuum freeze drying box for overnight freeze drying to obtain an etched
  • the resulting cobalt single atom nitrogen-carbon material (etched CoNC-3).
  • the aqueous alcohol solution for etching CoNC-3 was vigorously stirred for 2 hours, and then the ferric chloride solution was evenly added dropwise, and the iron ions were adsorbed on the surface of the etched CoNC-3 material by an immersion method.
  • Figure 80 is a scanning electron microscope (SEM) image of CoFeNC-3 of Example 20.
  • Figure 81 is an X-ray diffraction (XRD) diagram of CoFeNC-3 obtained in step 14 of Example 20, CoNC-3 obtained in step 5, and etched CoNC-3 obtained in step 9.
  • XRD X-ray diffraction
  • Figure 82 is a linear scanning polarization curve of oxygen reduction of the CoFeNC-3 diatomic material of Example 20, the CoNC-3 obtained in step 5, and the etched CoNC-3 obtained in step 9 under the alkaline condition of 0.1M KOH saturated with O2 and a rotation speed of 1600rmp.
  • Figure 82 shows that the half-wave potential of CoFeNC-3 is 0.819V, the half-wave potential of CoNC-3 is 0.788V, and the half-wave potential of etched CoNC-3 is 0.784V. Comparative analysis shows that the half-wave potential of CoFeNC-3 is the largest, indicating that its electrocatalytic oxygen reduction activity is the best.

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Abstract

本发明属于电催化技术领域，具体涉及一种金属双原子材料的制备方法。所述制备方法包括以下步骤：刻蚀：将负载有第一金属单原子的导电基底置于过氧化物水溶液中刻蚀，得到刻蚀后的第一金属单原子材料；金属双原子材料的制备：将上述得到的刻蚀后的第一金属单原子材料负载第二金属单原子，即得到金属双原子材料。本发明采用单原子金属材料为基底，通过过氧化物刻蚀单原子金属材料，以形成多孔且富含缺陷的金属氮碳材料，并向该材料中浸渍第二种金属前驱体，以形成原子间距在0～0.5纳米的双原子金属氮碳催化材料，可制得不同种类的双原子金属氮碳催化材料以满足不同催化体系的要求。

Description

一种金属双原子材料及其制备方法和用途 技术领域
本发明属于电催化技术领域，具体涉及一种金属双原子材料及其制备方法和用途。
背景技术
在氢氧燃料电池在中，相对于阳极的氢氧化反应，阴极的氧还原反应速率由于涉及四电子过程，反应速率较慢，是氢氧燃料电池中电池反应的决速步骤。因此需要利用高效催化剂来提高其氧还原反应速率。众多催化剂中，贵金属催化剂以其独特的催化性能一直活跃在当下的研究中。虽然贵金属类的催化剂的催化性能优异，然而由于贵金属如Pt、Pd、Ru、Ir等的储量有限和高成本等严肃问题，且属于不可再生资源的特性，严重限制了铂碳等贵金属催化剂的大规模使用。所以需要逐步采用替代者来降低贵金属的使用。而非贵金属相对于贵金属而言，在自然界拥有更丰富的含量，且在市场上呈现更低廉的价格，因此更适合长期可持续发展的总体要求。
在众多的氧还原电催化剂中，拥有更高的金属原子负载量和更灵活的活性位点的双原子金属催化剂是未来研究的重点。双原子催化剂在具备活性位点完全暴露、选择性高、原子利用率高达100％等优势的同时，邻近的两种不同金属间的协同作用还能进一步促进O-O键的断裂，还打破了反应中间体吸附能之间的线性关系，提高了金属负载量和氧还原速率，具有较大的应用潜能，适用于燃料电池和锌空电池等。
但是，目前合成的金属双原子材料通常使用的一锅水热法、预约束金属原子对策略、杂原子掺杂策略等来锚定不同的金属原子，以期合成金属双原子材料。但是这些方法合成的金属双原子材料中的金属原子对较少；而且采用的合成双原子的策略通常是一锅合成，其双原子的合成具有随机性和不确定性，同时对于一些指定组合的金属元素难以合成出双原子，因而缺乏对指定双原子的有效可控合成。对于一些指定组合的金属元素难以合成出双原子的原因是：由于一些金属例如Ni、Pt、Ru、Mn、Ir在反应过程中容易团聚形成纳米颗粒或者团簇，直接采用一锅合成难以稳定的锚定住金属原子，所以难以有效的合成出指定的双原子。
例如参考文献1《Wang Y,Li Z,Zhang P,et al.Flexible carbon nanofiber film with diatomic Fe-Co sites for efficient oxygen reduction and evolution reactions in  wearable zinc-air batteries[J].Nano Energy,2021,87.》图1可见，在2纳米的标尺下，即156.11平方纳米下，有9对金属双原子材料，原子对的数目较少。同时，较少的双原子数目也影响了金属双原子材料的电催化的氧还原活性和四电子选择性以及循环稳定性等等，如参考文献图2，其Fe1Co1-CNF金属双原子材料的半波电位仅为0.87V(注：半波电位数值越大，活性越大)。
再例如参考文献2《Zhong X,Ye S,Tang J,et al.Engineering Pt and Fe dual-metal single atoms anchored on nitrogen-doped carbon with high activity and durability towards oxygen reduction reaction for zinc-air battery[J].Applied Catalysis B:Environmental,2021,286:119891》采用的是高温煅烧法合成的双金属原子催化剂，由参考文献2的图1d可见，在2纳米的标尺下，即1126.388平方纳米下，有15对双金属原子，原子对的数目较少。同时，较少的双原子数目也影响了双金属原子催化剂的电催化的氧还原活性和四电子选择性以及循环稳定性等等，如参考文献2中图所示，其PtFe-NC双原子催化剂的半波电位为0.895V(注：半波电位数值越大，活性越大)。同时，PtFe-NC双原子催化剂的过氧化氢产率在0.1-0.8V的电位范围内低于5％(注：过氧化氢产率越低，电位范围越宽，4电子选择性越高)。而且，PtFe-NC双原子催化剂的循环稳定性较差(注：半波电位负移数值越小，循环时间越长，循环稳定性越高)，如参考文献2中图S26b所示，在5000圈的CV循环后，其PtFe-NC双原子催化剂的半波电位负移了13mV，稳定性较差。较少的双原子数目导致双金属原子催化剂在氧还原活性、四电子选择性以及循环稳定性方面欠佳。
因此，亟需一种能合成含有高密度的金属原子对的金属双原子材料的方法，来进一步提高金属双原子材料的氧还原活性。
发明内容
对此，本文开发了一种过氧化物刻蚀法可控合成金属双原子材料的方法，来合成高密度的金属双原子材料，此合成方法可有效可控的合成指定组合的双原子。此外采用此合成方法制备的金属双原子材料具有优异的的氧还原活性、四电子选择性和循环稳定性。例如，采用过氧化氢刻蚀法制备的金属双原子材料ZnFeNC同样在2纳米的标尺下，双金属原子对有56对，原子对的密度更高，表明这种合成方法具有独特的优越性，合成双金属原子对的成功率更高。此外，金属双原 子材料CoFeNC的半波电位为0.86V。表明通过过氧化物刻蚀法制备的金属双原子材料拥有优异的催化氧还原的活性、选择性和循环稳定性。
本发明第一方面提供一种金属双原子材料，所述金属双原子材料包含：导电基底和负载在所述导电基底上的第一金属单原子和第二金属单原子，其中第一金属单原子和第二金属单原子的距离小于或等于0.5纳米。
优选地，在导电基底上，一个第一金属单原子和其相邻的一个第二金属单原子形成一个双原子对，双原子对的密度不小于0.06对/平方纳米。
又优选地，双原子对的密度不小于0.08对/平方纳米。例如，双原子对的密度为0.09对/平方纳米(26对/275纳米)～0.21对/平方纳米(56对/265纳米)。
再优选地，双原子对的密度为0.10对/平方纳米(57对/555纳米)～0.21对/平方纳米(56对/265纳米)。
优选地，第一金属单原子和第二金属单原子之间的距离为0.1～0.5纳米。
再优选地，第一金属单原子和第二金属单原子之间的距离为0.11～0.5纳米。
优选地，所述第一金属单原子中的第一金属选自：钴、铁、锌、镍、锰、铂、钌、铱、金、银中的一种或几种；
所述第二金属单原子中的第二金属选自：钴、铁、锌、镍、锰、铂、钌、铱、金、银一种或几种。
当所述第一金属单原子中的第一金属选自：钴、铁、锌、镍、锰、铂、钌、铱、金、银中的几种，或者所述第二金属单原子中的第二金属选自：钴、铁、锌、镍、锰、铂、钌、铱、金、银中的几种时，所述导电基底上可以存在金属类型不同的多种双原子对。
例如：所述第一金属单原子中的第一金属选自钴和铁，所述第二金属单原子中的第二金属选自镍，则所述导电基底上存在的双原子对为：钴镍双原子对和铁镍双原子对。
再例如：所述第一金属单原子中的第一金属选自钴和铁，所述第二金属单原子中的第二金属选自镍和锰，则所述导电基底上存在的双原子对为：钴镍双原子对、铁镍双原子对、钴锰双原子对和铁锰双原子对。
所述第一金属单原子与第二金属单原子相同或者不同。
优选地，所述导电基底选自：氮碳材料或硫氮碳材料。刻蚀步骤中，过氧化 物刻蚀的氮碳材料或硫氮碳材料的位点是碳原子，因此暴露出更多氮原子，提高了氮/碳比例，从而能有效吸附第二金属单原子。
优选地，所述第一金属单原子为铁单原子，第二金属单原子为铂单原子，铁单原子和铂单原子之间的距离为0.14～0.5纳米。
优选地，在导电基底上，双原子对的密度不小于0.06对/平方纳米。
更优选地，在导电基底上，双原子对的密度为0.09对/平方纳米(15对/158.24平方纳米)～0.18对/平方纳米(21对/112平方纳米)。
优选地，所述第一金属单原子为钴单原子，第二金属单原子为铁单原子。
钴单原子和铁单原子之间的距离为0.1～0.5纳米。
再优选地，钴单原子和铁单原子之间的距离为0.15～0.5纳米。
优选地，在所述导电基底上，一个钴单原子和其相邻的一个铁单原子组成一个双原子对。
优选地，在所述导电基底上，双原子对的密度不小于0.06对/平方纳米。
更优选地，在所述导电基底上，双原子对的密度为0.10对/平方纳米(29对/280平方纳米)～0.16对/平方纳米(44对/280平方纳米)。
本发明第二方面提供第一方面所述的金属双原子材料的制备方法，所述制备方法包括以下步骤：
刻蚀：将负载有第一金属单原子的导电基底置于过氧化物水溶液中刻蚀，得到刻蚀后的第一金属单原子材料；
金属双原子材料的制备：将上述得到的刻蚀后的第一金属单原子材料负载第二金属单原子，即得到金属双原子材料。
优选地，所述刻蚀的具体方法如下：
步骤A、将醇和水混合成溶液，将负载有第一金属单原子的导电基底置于混合溶液中，超声；
步骤B、将步骤A得到的混合溶液搅拌同时均匀滴加过氧化物水溶液，得混合均匀的反应液；
步骤C、将步骤B得到的反应液转移到高压反应釜中，置于烘箱中，设定反应温度为100℃～200℃，反应3-10小时；反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤和洗涤，并真空冷冻干燥，得到刻蚀后的第一金属单 原子材料。
上述步骤B得到的反应液中，负载有第一金属单原子的导电基底的浓度为1mg/mL-5mg/mL，过氧化物的浓度为0.1mol/L～1.0mol/L。
优选地，所述金属双原子材料的制备具体方法如下：
将刻蚀后的第一金属单原子材料溶解于醇和水的混合溶液中，超声直至得到分散均匀的浑浊液，并称取适量的第二金属的前驱体加入浑浊液得到混合液，混合均匀，固液分离，并将得到的固体材料进行真空冷冻干燥；
将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体的保护下碳化，之后自然降温至室温，最终得到金属双原子材料。
上述称取适量的第二金属的前驱体加入浑浊液后的混合液中，刻蚀后的第一金属单原子材料的浓度为1mg/mL-5mg/mL，第二金属的前驱体的浓度为0.001mol/L～0.024mol/L。
优选地，所述过氧化物水溶液中的过氧化物选自过氧化氢、过氧二硫酸盐、过硫酸盐、过氧乙酸盐、过氧磷酸盐或过氧碳酸盐中的一种或几种。
优选地，所述导电基底为氮碳基底时，所述负载有第一金属单原子的导电基底的制备方法如下：
(a)将甲酰胺作为溶剂溶解第一金属盐和锌盐，超声以确保两种盐类充分溶解于甲酰胺中，得到水热反应母液A，第一金属盐和锌盐的摩尔比为1:4～1:20；
(b)将上述水热反应母液A倒入密闭反应釜中，在160℃～220℃和自生压力下进行水热反应，结束后，将密封反应釜自然冷却至室温，固液分离，洗涤固体，得到无甲酰胺残留的固体材料B，并将固体材料B烘干得到固体材料C；
(c)将固体材料C研磨后置于瓷舟内，在惰性气体保护下升温，再在800℃-1100℃下，恒温2-6小时，待反应结束后自然冷却至室温，制得所述负载有第一金属单原子的导电基底。
所述导电基底为硫氮碳基底时，所述负载有第一金属单原子的导电基底的制备方法如下：
(a)将甲酰胺作为溶剂溶解第一金属盐、锌盐和硫源，超声以确保两种盐类充分溶解于甲酰胺中，得到水热反应母液A，第一金属盐和锌盐的摩尔比为1:4～1:20，硫源的摩尔量和第一金属盐保持一致；
(b)将上述水热反应母液A倒入密闭反应釜中，在160℃～220℃和自生压力下进行水热反应，结束后，将密封反应釜自然冷却至室温，固液分离，洗涤固体，得到无甲酰胺残留的固体材料B，并将固体材料B烘干得到固体材料C；
(c)将固体材料C研磨后置于瓷舟内，在惰性气体保护下升温，再在600℃～1100℃下恒温1～4小时，待反应结束后自然冷却至室温，制得所述负载有第一金属单原子的导电基底。
优选地，所述第一金属盐中的第一金属选自：钴、铁、锌、镍、锰、铂、钌、铱、金、银中的一种或几种。第一金属盐可以为第一金属硝酸盐、第一金属硫酸盐或第一金属氯化物等。
优选地，所述第二金属的前驱体为第二金属盐，第二金属选自：钴、铁、锌、镍、锰、铂、钌、铱、金、银一种或几种。第二金属盐可以为第二金属硝酸盐、第二金属硫酸盐或第二金属氯化物等。
本发明第三方面提供第一方面所述的金属双原子材料用于催化氧还原反应的用途。
上述技术方案在不矛盾的前提下，可以自由组合。
相对于现有技术，本发明具有以下有益效果：
1、本发明采用单原子金属材料为基底(包括但不限于单原子金属氮碳材料)，通过过氧化物刻蚀单原子金属材料，以形成多孔且富含缺陷的金属氮碳材料，并向该材料中浸渍第二种金属前驱体，以形成原子间距在0～0.5纳米的双原子金属氮碳催化材料。通过调控不同的金属物种的比例和金属种类、刻蚀剂种类(过氧化氢、过氧二硫酸盐、过硫酸盐、过氧乙酸盐、过氧磷酸盐、过氧碳酸盐)、刻蚀剂加入量和刻蚀温度，可制得不同种类的双原子金属氮碳催化材料以满足不同催化体系的要求。
2、相比于现有的双原子制备方法，例如一锅水热法制备的金属双原子材料。本发明采用过氧化物刻蚀法制备的金属双原子材料有更高的双原子密度，本发明的方法更加可控，双原子位点成功概率高。
3、本发明采用过氧化物氧化刻蚀金属单原子材料的方法能有效制造缺陷和空位以合成原子级分散的异双原子金属氮碳催化剂。这种合成方法具有普适性，能合成异双原子金属催化剂和同双原子金属催化剂。
4、与现有的非贵金属双原子催化剂相比，本发明的异双原子金属催化剂在 碱性条件下具有优异的氧还原性能，例如ZnFeNC金属双原子材料的氧还原的半波电位为0.876V。
5、本发明中，若第一金属单原子和第二单原子不同，则为异双原子金属催化剂材料。异双原子金属催化剂材料中，两种不同的原子间存在协同作用提高了催化剂催化氧还原的活性，同时也提高了氧还原反应速率。
6、特别的，本发明的铁铂金属双原子材料中，铁单原子和铂单原子之间的距离小于或等于0.5纳米，在所述导电基底上，双原子对的密度为0.09对/平方纳米(15对/158.24平方纳米)～0.18对/平方纳米(21对/112平方纳米)。这表明本文合成方法具有独特的优越性，合成双金属原子对的成功率更高。因此，本发明的铁铂金属双原子材料中双原子位点更多，两种不同的原子间存在协同作用，提高了催化剂催化氧还原的活性，同时也提高了氧还原反应速率，同时材料的选择性和稳定性也得到大幅度提高。
7、特别的，本发明的钴铁金属双原子材料中，钴单原子和铁单原子之间的距离小于或等于0.5纳米，在所述导电基底上，双原子对的密度为0.10对/平方纳米(29对/280平方纳米)～0.16对/平方纳米(44对/280平方纳米)，原子对的密度更高。这表明本文合成方法具有独特的优越性，合成双金属原子对的成功率更高。因此，本发明的钴铁金属双原子材料中双原子位点更多，两种不同的原子间存在协同作用，提高了催化剂催化氧还原的活性，同时也提高了氧还原反应速率，同时材料的选择性和稳定性也得到大幅度提高。
附图说明
图1为参考文献1中，Fe1Co1-CNF金属双原子材料的高角环形暗场扫描透射图。
图2为参考文献1中Fe1Co1-CNF金属双原子材料在0.5V电位下工作10000s前后的氧还原极化曲线。
图3为实施例1中，ZnFeNC金属双原子材料的扫描电镜图(SEM)。
图4为实施例1中，ZnFeNC金属双原子材料的透射电镜图(TEM)
图5为实施例1中，ZnFeNC金属双原子材料的X射线衍射图(XRD)。
图6为实施例1中，ZnFeNC金属双原子材料的高角环形暗场扫描透射图(HADDF-STEM)。
图7为实施例1中ZnNC、刻蚀ZnNC和ZnFeNC的XPS的Zn2p谱图分峰拟合图。
图8为为实施例1中ZnFeNC的XPS的Fe2p谱图分峰拟合图。
图9为实施例1中在0.1M KOH的碱性条件下，ZnFeNC金属双原子材料与各单金属催化剂的线性扫描曲线比较图。
图10为为实施例1中在0.1M KOH的碱性条件下，ZnFeNC金属双原子材料与20％Pt/C的循环稳定性图。
图11为实施例2中，f-CoNiNC-1金属双原子材料的扫描电镜图(SEM)。
图12为实施例2中，f-CoNiNC-1金属双原子材料的透射电镜图(TEM)。
图13为实施例2中，f-CoNiNC-1金属双原子材料、f-CoNiNC-2金属双原子材料、步骤5得到的f-CoNC、步骤9得到的刻蚀f-CoNC的X射线衍射图(XRD)。
图14为实施例2中，f-CoNiNC金属双原子材料的高角环形暗场扫描透射图(HAADF-STEM)。
图15为实施例2中在0.1M KOH的碱性条件下，f-CoNiNC-1和f-CoNiNC-2金属双原子材料与各单金属催化剂的线性扫描曲线比较。
图16为实施例3中，f-CoCoNC金属双原子材料的扫描电镜图(SEM)。
图17为实施例3中，f-CoCoNC金属双原子材料的透射电镜图(TEM)。
图18为实施例3中，f-CoCoNC金属双原子材料的X射线衍射图(XRD)。
图19为实施例3中，f-CoCoNC金属双原子材料的高角环形暗场扫描透射图(HAADF-STEM)。
图20为实施例3中在0.1M KOH的碱性条件下，f-CoCoNC金属双原子材料与各单金属催化剂的线性扫描曲线比较。
图21为实施例4中，FeRuNC金属双原子材料的扫描电镜图(SEM)。
图22为实施例4中，FeRuNC金属双原子材料的透射电镜图(TEM)。
图23为实施例4中，f-FeRuNC金属双原子材料、FeNC、刻蚀FeNC的X射线衍射图(XRD)。
图24在0.1M KOH的碱性条件下，FeRuNC金属双原子材料与各单金属催化剂的线性扫描曲线比较。
图25为实施例5中，NiPtNC金属双原子材料的扫描电镜图(SEM)。
图26为实施例5中，NiPtNC金属双原子材料的透射电镜图(TEM)。
图27为实施例5中，NiPtNC金属双原子材料、步骤5得到的NiNC材料、步骤9得到的刻蚀NiPNC材料的X射线衍射图(XRD)。
图28为在0.1M KOH的碱性条件下，NiPtNC金属双原子材料与各单金属催化剂的线性扫描曲线比较。
图29为实施例6中，CoIrNC金属双原子材料的扫描电镜图(SEM)。
图30为实施例6中，CoIrNC金属双原子材料的透射电镜图(TEM)。
图31为实施例6中，CoIrNC金属双原子材料的X射线衍射图(XRD)。
图32为在0.1M KOH的碱性条件下，CoIrNC金属双原子材料与各单金属催化剂的线性扫描曲线比较。
图33为实施例7中，MnRuNC金属双原子材料的扫描电镜图(SEM)。
图34为在0.1M KOH的碱性条件下，MnRuNC金属双原子材料与各单金属催化剂的线性扫描曲线比较。
图35为实施例8中，MnPtNC金属双原子材料的扫描电镜图(SEM)。
图36为在0.1M KOH的碱性条件下，MnPtNC金属双原子材料与各单金属催化剂的线性扫描曲线比较。
图37为实施例9中，NiAuNC金属双原子材料的扫描电镜图(SEM)。
图38为在0.1M KOH的碱性条件下，NiAuNC金属双原子材料与各单金属催化剂的线性扫描曲线比较。
图39为实施例10中，NiAgNC金属双原子材料的扫描电镜图(SEM)。
图40为在0.1M KOH的碱性条件下，NiAgNC金属双原子材料与各单金属催化剂的线性扫描曲线比较。
图41为实施例11中，FeRuSNC金属双原子材料的扫描电镜图(SEM)。
图42为实施例11中，FeRuSNC金属双原子材料的透射电镜图(TEM)。
图43为实施例11中，FeRuSNC金属双原子材料、FeSNC、刻蚀FeSNC的X射线衍射图(XRD)。
图44为实施例11中，为在0.1M KOH的碱性条件下，FeRuSNC金属双原子材料与各单金属催化剂的线性扫描曲线比较。
图45为实施例2中，为f-CoNC和刻蚀f-CoNC材料的XPS全谱数据比较。
图46为实施例12的FePtNC-1的扫描电子显微镜(SEM)图片。
图47为实施例12的FePtNC-1的透射电子显微镜(TEM)。
图48为实施例12的FePtNC-1的高角环形暗场扫描透射电子显微镜(HAADF-STEM)图片。
图49为实施例12的FePtNC-1、FeNC-1和刻蚀FeNC-1的X射线衍射(XRD)图。
图50为实施例12的FePtNC-1双金属原子催化剂、FeNC-1和刻蚀FeNC-1、20wt％Pt/C材料在1600rmp下的氧还原的线性扫描极化曲线。
图51为实施例12的FePtNC-1双金属原子催化剂和20wt％Pt/C材料的四电子转移数和过氧化氢产率。
图52为实施例12的FePtNC-1双原子材料和20wt％Pt/C材料工作10000圈前后的氧还原极化曲线。
图53为实施例13的FePtNC-2双原子材料的扫描电子显微镜(SEM)图。
图54为实施例13步骤13得到的FePtNC-2双原子材料、步骤5得到的FeNC-2、步骤9得到的刻蚀FeNC-2的X射线衍射(XRD)图。。
图55为实施例13的FePtNC-2双原子材料的高角环形暗场扫描透射电子显微镜(HAADF-STEM)图片。
图56为实施例13的FePtNC-2双原子材料、步骤5得到的FeNC-2、步骤9得到的刻蚀FeNC-2在O2饱和的0.1M KOH的碱性条件，转速1600rmp下的氧还原的线性扫描极化曲线。
图57为实施例14的FePtNC-3双原子材料的扫描电子显微镜(SEM)图。
图58为实施例14步骤13得到的FePtNC-3双原子材料、步骤5得到的FeNC-3、步骤9得到的刻蚀FeNC-3的X射线衍射(XRD)图。
图59为实施14的FePtNC-3双原子材料、步骤5得到的FeNC-3、步骤9得到的刻蚀FeNC-3在1600rmp下的氧还原的线性扫描极化曲线。
图60为实施例15的FePtSNC-1的扫描电子显微镜(SEM)图。
图61为实施例15步骤13得到的FePtSNC-1、步骤5得到的FeSNC-1、步骤9得到的刻蚀FeSNC-1的X射线衍射(XRD)图。
图62为实施例15的FePtSNC-1双金属原子材料、步骤5得到的FeSNC-1、 步骤9得到的刻蚀FeSNC-1在1600rmp下的氧还原的线性扫描极化曲线。
图63为实施例16的FePtSNC-2的扫描电子显微镜(SEM)图。
图64为实施例16步骤13得到的FePtSNC-2、步骤5得到的FeSNC-2、步骤9得到的刻蚀FeSNC-2的X射线衍射(XRD)图。
图65为实施例16的FePtSNC-2双金属原子材料、步骤5得到的FeSNC-2、步骤9得到的刻蚀FeSNC-2在1600rmp下的氧还原的线性扫描极化曲线。
图66为实施例17的FePtSNC-3的扫描电子显微镜(SEM)图。
图67为实施例17步骤13得到的FePtSNC-3、步骤5得到的FeSNC-3、步骤9得到的刻蚀FeSNC-3的X射线衍射(XRD)图。
图68为实施例17的FePtSNC-3双金属原子材料、步骤5得到的FeSNC-3、步骤9得到的刻蚀FeSNC-3在1600rmp下的氧还原的线性扫描极化曲线。
图69为实施例18的CoFeNC-1双原子材料的扫描电子显微镜(SEM)图片。
图70为实施例18的CoFeNC-1双原子材料的透射电子显微镜(TEM)。
图71为实施例18的CoFeNC-1双原子材料的高角环形暗场扫描透射电子显微镜(HAADF-STEM)图片。
图72为实施例18的CoFeNC-1双原子材料、CoNC-1和刻蚀CoNC-1的X射线衍射(XRD)图。
图73为实施例18的CoFeNC-1双原子材料、刻蚀CoNC-1、FeNC、CoNC-1、20wt％Pt/C材料在1600rmp下的氧还原的线性扫描极化曲线。
图74为实施例18的CoFeNC-1双原子材料和20wt％Pt/C材料的四电子转移数和过氧化氢产率。
图75为实施例18的CoFeNC-1双原子材料和20wt％Pt/C材料工作40000秒前后的氧还原极化曲线。
图76为实施例19的CoFeNC-2双原子材料的扫描电子显微镜(SEM)图。
图77为实施例19步骤14得到的CoFeNC-2双原子材料、步骤5得到的CoNC-2、步骤9得到的刻蚀CoNC-2的X射线衍射(XRD)图。
图78为实施例19的CoFeNC-2双原子材料的高角环形暗场扫描透射电子显微镜(HAADF-STEM)图片。
图79为实施例19的步骤14得到的CoFeNC-2双原子材料、步骤5得到的 CoNC-2、步骤9得到的刻蚀CoNC-2、FeNC-2、20wt％Pt/C材料在O2饱和的0.1M KOH的碱性条件，转速1600rmp下的氧还原的线性扫描极化曲线。
图80为实施例20的CoFeNC-3双原子材料的扫描电子显微镜(SEM)图。
图81为实施例20的CoFeNC-3双原子材料的X射线衍射(XRD)图。
图82为实施例20的CoFeNC-3双原子材料、步骤5得到的CoNC-3、步骤9得到的刻蚀CoNC-3在1600rmp下的氧还原的线性扫描极化曲线。
具体实施方式
下面对本发明通过实施例作进一步说明,但不仅限于本实施例。实施例中未注明具体条件的实验方法,通常按照常规条件以及手册中所述的条件，或按照制造厂商所建议的条件所用的通用设备、材料、试剂等,如无特殊说明,均可从商业途径得到。以下实施例和对比例中所需要的原料均为市售。
实施例1
ZnFeNC金属双原子材料的制备方法：
1、将30mL甲酰胺作为溶剂溶解无水氯化锌，超声30分钟以确保无水氯化锌充分溶解与甲酰胺中，得到的澄清色溶液为水热反应母液A；水热反应母液A中无水氯化锌的浓度为0.01mol L-1。
2、将上述母液A倒入清洁干燥的密闭反应釜中，在180℃水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在800℃的温度下恒温碳化2小时，待恒温结束后自然冷却至室温，制得锌单原子氮碳材料(ZnNC)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合得到混合溶液，将上述合成的50mg锌单原子氮碳材料溶于上述混合溶液中，超声30分钟直至其分散均匀得到混合溶液D。
7、将步骤6得到的混合溶液D置于常温搅拌台上搅拌10分钟，在搅拌期间均匀滴加0.25mL的30％(10mol/L)的过氧化氢溶液，得混合均匀的反应液E，反应液E中过氧化氢的浓度为0.1mol/L，锌单原子氮碳材料ZnNC的浓度为2mg/mL)
8、将反应液E转移到高压反应釜中，置于200℃烘箱中，反应6小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的锌单原子氮碳材料(刻蚀ZnNC)。
10、称取50mg的刻蚀ZnNC材料的干燥固体，将其溶解于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，超声1小时后，转移到常温搅拌台上，得到刻蚀ZnNC的水醇溶液。
11、称取0.00025mol的三氯化铁粉末溶于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，并超声至溶解，得到0.01mol L-1的三氯化铁溶液。
12、将步骤10得到的刻蚀ZnNC的水醇溶液在剧烈搅拌2小时下，均匀滴加入步骤11得到的三氯化铁溶液，通过浸渍法使铁离子吸附在刻蚀ZnNC材料表面。
13、2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
14、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至800℃并恒温碳化1小时，之后进行自然降温至室温。最终得到ZnFeNC异核双原子金属氮碳催化剂。
对上述步骤(5)得到的ZnNC、步骤(9)得到的刻蚀ZnNC、步骤(14)得到的ZnFeNC进行表征：
图3为实施例1中，ZnFeNC金属双原子材料的扫描电镜图(SEM)。
图4为实施例1中，ZnFeNC金属双原子材料的透射电镜图(TEM)。在50纳米的标尺下，没有出现金属锌或铁的纳米颗粒。
图5为实施例1中，ZnFeNC金属双原子材料的X射线衍射图(XRD)。
图4和图5证明双原子未形成金属纳米颗粒或合金。
图6为实施例1中，ZnFeNC金属双原子材料的高角环形暗场扫描透射图(HADDF-STEM)。图6可见：第一单原子Zn和第二单原子Fe之间的距离小为0.5nm。
表1为实施例1中，ZnFeNC金属双原子材料的56对原子对的间距统计表。统计结果显示，所有的原子对的间距都小于0.5纳米。具体的第一单原子Zn和第二单原子Fe之间的距离为0.11～0.5nm。
在2纳米的标尺下，即265平方纳米的范围内，双原子位点较多，总计有56对双金属原子，双原子对的密度为0.21对/平方纳米。表明双原子成功概率较高。本申请中，高角环形暗场扫描透射图(HAADF-STEM)图片的面积，由发明人根据图片中的标尺和图片实际大小通过计算换算得到。
表1
图7为ZnNC、刻蚀ZnNC和ZnFeNC的XPS的Zn2p谱图分峰拟合图。表明Zn为Zn2+。
图8为ZnFeNC的XPS的Fe2p谱图分峰拟合图。根据分峰结果表明该材料中含有Fe2+和Fe3+的不同氧化态的铁元素。
图9为0.1M KOH下ZnFeNC金属双原子材料与各单金属催化剂的线性扫描曲线比较图。
其中，FeNC的制备方法如下：FeNC的制备与实施例1中，1-5步骤中ZnNC的制备一致，仅需把锌盐更换为铁盐，即乙酰丙酮铁，其摩尔浓度为0.005mol/L。制备得到的材料为FeNC。
ZnNC来源是按实施例1中的制备过程制备，步骤5得到的产物。
ZnFeNC一锅法的制备方法如下：
将0.1mol/L的无水氯化锌、0.01mol/L的无水氯化铁溶解于30mL的甲酰胺溶剂里，超声直至分散均匀。将反应液置于180℃的烘箱中反应12小时，自然冷却后，抽滤并于60℃的烘箱中干燥。再将干燥的粉末于800℃的管式炉中进行碳化2小时，其中升温速率为5℃/min，保护气为氩气。
刻蚀ZnNC来源是按实施例1中的制备过程制备，步骤9得到的产物。
20％Pt/C材料是Pt质量含量为20％的Pt/C材料，即20wt％Pt/C，可以市场购买获得。
从图9中可见，ZnFeNC金属双原子材料的起始电位为1.00V，其半波电位为0.876V。FeNC的起始电位为0.98V，其半波电位为0.63V。ZnNC的起始电位为0.93V，其半波电位为0.693V。ZnFeNC一锅法的起始电位为0.98V，其半波电位为0.68V。20％Pt/C的起始电位为0.99V，其半波电位为0.84V。图9证明，相比图9中其他材料，ZnFeNC金属双原子材料的电催化氧还原活性更加优异。
图10为在0.1M KOH的碱性条件下，ZnFeNC金属双原子材料与20％Pt/C的循环稳定性图。二者在经历5000圈的CV循环后，ZnFeNC金属双原子材料的半波电位仅衰减了16mV，但20％Pt/C半波电位衰减了51mV。这说明ZnFeNC金属双原子材料的循环稳定性能更好。
实施例2
CoNiNC金属双原子材料的制备方法如下：
1、将30mL甲酰胺作为溶剂溶解钴盐和锌盐，超声30分钟以确保两种盐类充分溶解与甲酰胺中，得到的澄清粉色溶液为水热反应母液A；钴盐和锌盐的摩尔比为1:10，上述钴盐为无水氯化钴，锌盐为无水氯化锌。水热反应母液A中，无水氯化钴的浓度为0.025mol/L，无水氯化锌的浓度为0.1mol/L。
2、将上述母液A倒入清洁干燥的密闭反应釜中，在220℃下水热反应10小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材 料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在1100℃的温度下恒温碳化2小时，待恒温结束后自然冷却至室温，制得钴单原子氮碳材料(f-CoNC)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合得到混合溶液，将上述合成的125mg钴氮碳材料溶于上述混合溶液中，超声1小时后使其分散均匀得到混合溶液D。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加2.53mL的10mol/L的过氧化氢，得混合均匀的反应液E。反应液E中，负载有第一金属单原子的导电基底的浓度为5mg/mL，过氧化物的浓度为1.0mol/L。
8、将反应液E转移到高压反应釜中，置于200℃烘箱中，反应10小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的钴单原子氮碳材料(刻蚀f-CoNC)。
10、称取250mg的刻蚀f-CoNC材料的干燥固体，将其溶解于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中。超声1小时后，转移到恒温搅拌台上，得到刻蚀f-CoNC的水醇溶液。
11、称取适量氯化镍粉末溶于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，并超声至溶解，得到0.75mg/mL(即0.006mol/L)或1.27mg/mL(即0.01mol/L)的氯化镍溶液。
12、将步骤10得到的刻蚀f-CoNC的水醇溶液在剧烈搅拌2小时下，并均匀滴加入将步骤11得到的25mL 0.75mgNi/mL或1.27mgNi/mL的氯化镍溶液得到混合液，通过浸渍法使镍离子吸附在刻蚀f-CoNC材料表面。此步骤12，混合液中，刻蚀f-CoNC材料的浓度为5mg/mL。
13、对步骤12得到的混合液进行2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行过夜真空冷冻干燥。
14、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至900℃并恒温碳化1小时，之后进行自然降温至室温。最终得到CoNiNC异核双原子金属氮碳催化剂(f-CoNiNC-1或f-CoNiNC-2)。
图11为实施例2中，f-CoNiNC-1金属双原子材料的扫描电镜图(SEM)。
图12为实施例2中，f-CoNiNC金属双原子材料的透射电镜图(TEM)。在5纳米的标尺下，没有出现金属钴或镍的纳米颗粒。
步骤12中，氯化镍溶液浓度为0.75mgNi/mL时，产物为f-CoNiNC-1。
步骤12中，氯化镍溶液浓度为1.27mgNi/mL时，产物为f-CoNiNC-2。
图13为实施例2中，f-CoNiNC-1金属双原子材料、f-CoNiNC-2金属双原子材料的X射线衍射图(XRD)。
图12和图13证明f-CoNiNC-1金属双原子材料和f-CoNiNC-2金属双原子材料中都没有金属钴和金属镍的纳米颗粒。
图14为实施例2中，f-CoNiNC-1金属双原子材料的高角环形暗场扫描透射图(HAADF-STEM)。
图14可见，在5纳米的标尺下，即555平方纳米的范围内，双原子位点较多，总计有57对双金属原子，双原子对的密度为0.10对/平方纳米。表明双原子成功概率较高。
图15为在0.1M KOH的碱性条件下，f-CoNiNC-1和f-CoNiNC-2金属双原子材料与各单金属催化剂的线性扫描曲线比较。各单金属催化剂分别为步骤5得到的f-CoNC、步骤9得到的刻蚀f-CoNC。
f-CoNiNC-1和f-CoNiNC-2金属双原子材料的半波电位分别为0.808V和0.810V。步骤5得到的f-CoNC的半波电位为0.801V、步骤9得到的刻蚀f-CoNC的半波电位为0.793V。图15证明：f-CoNiNC-1和f-CoNiNC-2催化性能优于步骤5得到的f-CoNC、步骤9得到的刻蚀f-CoNC。
图45为实施例2中，为f-CoNC和刻蚀f-CoNC材料的XPS全谱数据比较。通过图45中步骤5得到的f-CoNC和步骤9得到的刻蚀f-CoNC的XPS全谱数据比较发现，刻蚀f-CoNC的C 1s峰强度明显低于f-CoNC的C 1s峰强度，说明刻蚀的主要是碳原子位点。同时，刻蚀f-CoNC的N 1s峰强度明显高于f-CoNC 的N 1s峰强度，说明刻蚀后暴露出更多的氮原子。材料表面暴露更多的氮原子能更加有效的锚定更多的第二金属原子。这也为合成高密度的双原子垫定了良好的基础。
实施例3：
f-CoCoNC金属双原子材料的制备方法如下：
1、将30mL甲酰胺作为溶剂溶解钴盐和锌盐，超声30分钟以确保两种盐类充分溶解与甲酰胺中，得到的澄清粉色溶液为水热反应母液A；钴盐和锌盐的摩尔比为1:10，上述钴盐为无水氯化钴，锌盐为无水氯化锌。水热反应母液A中，无水氯化钴的浓度为0.025mol/L，无水氯化锌的浓度为0.1mol/L。
2、将上述母液A倒入清洁干燥的密闭反应釜中，在160℃和自生压力下水热反应18小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在900℃的温度下恒温碳化6小时，待恒温结束后自然冷却至室温，制得钴单原子氮碳材料(f-CoNC)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合成溶液，将上述合成的25mg钴氮碳材料溶于混合溶液D中，超声1小时直至其分散均匀。
7、将D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加0.25mL的质量分数为10mol/L的过氧乙酸盐，得混合均匀的反应液E。反应液中得到的钴单原子氮碳材料的浓度为1mg/mL，过氧乙酸盐的浓度为0.1mol/L。
8、将反应液E转移到高压反应釜中，置于100℃烘箱中，反应3小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的钴单原子氮碳材料，为刻蚀f-CoNC。
10、称取50mg的刻蚀f-CoNC材料的干燥固体，将其溶解于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，超声1小时后，转移到常温搅拌台上，得到刻蚀f-CoNC的水醇溶液。
11、称取0.0324mg氯化钴粉末溶于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，并超声至溶解，得到1.30mg/mL(即0.01mol/L)的氯化钴溶液。
12、将步骤10得到的刻蚀f-CoNC的水醇溶液在剧烈搅拌2小时下，均匀滴加入步骤11得到的氯化钴溶液，通过浸渍法使镍离子吸附在刻蚀f-CoNC材料表面。
13、对步骤12得到的混合物进行2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
14、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至600℃并恒温碳化4小时，之后进行自然降温至室温。最终得到f-CoCoNC同核金属双原子材料。
图16为实施例3中，f-CoCoNC金属双原子材料的扫描电镜图(SEM)。
图17为实施例3中，f-CoCoNC金属双原子材料的透射电镜图(TEM)。在50纳米的标尺下，没有出现金属钴的纳米颗粒。
图18为实施例3中，f-CoCoNC金属双原子材料、步骤5得到的f-CoNC、步骤9得到的刻蚀f-CoNC的X射线衍射图(XRD)。
图17和图18证明f-CoCoNC金属双原子材料中没有金属钴的纳米颗粒。
图19为实施例3中，f-CoCoNC金属双原子材料的高角环形暗场扫描透射图(HAADF-STEM)。
图19可见，在2纳米的标尺下，即275平方纳米的范围内，双原子位点较多，总计有26对双金属原子，双原子对的密度为0.09对/平方纳米。表明双原子成功概率较高。
图20为在0.1M KOH的碱性条件下，f-CoCoNC金属双原子材料与各单金属催化剂(步骤5得到的f-CoNC、步骤9得到的刻蚀f-CoNC)的线性扫描曲线比较。f-CoCoNC金属双原子材料的半波电位为0.800V，步骤5得到的f-CoNC的半波电位为0.795V、步骤9得到的刻蚀f-CoNC的半波电位为0.794V。这说 明在碱性条件下能催化氧还原性能优于步骤5得到的f-CoNC、步骤9得到的刻蚀f-CoNC。
实施例4：
FeRuNC金属双原子材料的制备方法如下：
1、将30mL甲酰胺作为溶剂溶解铁盐和锌盐，超声30分钟直至两种盐类充分溶解与甲酰胺中，得到的均一红褐色溶液为水热反应母液A；铁盐和锌盐的摩尔比为1:20，上述铁盐为乙酰丙酮铁，锌盐为无水氯化锌。水热反应母液A中，乙酰丙酮铁的浓度为0.005mol/L，无水氯化锌的浓度为0.2mol/L。
2、将上述母液A倒入清洁干燥的密闭反应釜中，在180℃下水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在900℃的温度下恒温碳化2小时，待恒温结束后自然冷却至室温，制得铁单原子氮碳材料(FeNC)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合成溶液，将上述合成的50mg铁氮碳材料溶于混合溶液D中，超声1小时直至其分散均匀。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加0.25mL的10mol/L的过硫酸钠溶液，得混合均匀的反应液E。
8、将反应液E转移到高压反应釜中，置于110℃烘箱中，反应3小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的铁单原子氮碳材料(刻蚀FeNC)。
10、称取50mg的刻蚀FeNC材料的干燥固体，将其溶解于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，超声1小时后，转移到恒温搅拌台上，得到刻蚀FeNC的水醇溶液。
11、称取适量的氯化钌粉末溶于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，并超声至溶解，得到10mg/mL(即0.0480mol/L)的氯化钌溶液。
12、将步骤10得到的刻蚀FeNC的水醇溶液在剧烈搅拌2小时下，均匀滴加入步骤11得到的氯化钌溶液得到混合液，通过浸渍法使钌离子吸附在刻蚀FeNC材料表面。混合液中，刻蚀FeNC材料的浓度为1mg/mL，氯化钌的浓度为0.0240mol/L。
13、对步骤12得到的混合液进行2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
14、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至950℃并恒温碳化1小时，之后进行自然降温至室温。最终得到FeRuNC异核双原子金属氮碳催化剂。
图21为实施例4中，FeRuNC金属双原子材料的扫描电镜图(SEM)。
图22为实施例4中，FeRuNC金属双原子材料的透射电镜图(TEM)。在50纳米的标尺下，没有出现金属铁或钌的纳米颗粒。
图23为实施例4中，FeRuNC金属双原子材料、步骤5得到的FeNC、步骤9得到的刻蚀FeNC的X射线衍射图(XRD)。
图22和图23证明FeRuNC金属双原子材料中没有金属铁和金属钌的纳米颗粒。
图24为在0.1M KOH的碱性条件下，FeRuNC金属双原子材料与各单金属催化剂(步骤5得到的FeNC、步骤9得到的刻蚀FeNC)的线性扫描曲线比较。FeRuNC金属双原子材料的半波电位为0.886V。步骤5得到的FeNC的半波电位为0.853V、步骤9得到的刻蚀FeNC的半波电位为0.842V。这说明FeRuNC金属双原子材料电催化氧还原活性优于步骤5得到的FeNC、步骤9得到的刻蚀FeNC。
实施例5：
NiPtNC金属双原子材料
1、将30mL甲酰胺作为溶剂溶解镍盐和锌盐，超声30分钟直至两种盐类充分溶解与甲酰胺中，得到的均一的水热反应母液A；镍盐和锌盐的摩尔比为1:20，上述铁盐为无水氯化镍，锌盐为无水氯化锌。水热反应母液A中，无水氯化镍的浓度为0.01mol/L，无水氯化锌的浓度为0.1mol/L。
2、将上述母液A倒入清洁干燥的密闭反应釜中，在180℃下水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在900℃的温度下恒温碳化2小时，待恒温结束后自然冷却至室温，制得镍单原子氮碳材料(NiNC)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合得到混合溶液，将上述合成的50mg镍氮碳材料溶于上述混合溶液中，超声1小时直至其分散均匀，得到混合溶液D。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加0.25mL的10mol/L的过氧磷酸盐溶液，得混合均匀的反应液E。
8、将反应液E转移到高压反应釜中，置于200℃烘箱中，反应3小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的铁单原子氮碳材料(刻蚀NiNC)。
10、称取50mg的刻蚀NiNC材料的干燥固体，将其溶解于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，超声1小时后，转移到恒温搅拌台上，得到刻蚀NiNC的水醇溶液。
11、移取取适量的氯铂酸溶于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，并超声至分散均一，得到10mg/mL(0.024mol/L)的氯铂酸溶液。
12、将步骤10得到的刻蚀NiNC的水醇溶液在剧烈搅拌2小时下，均匀滴加入步骤11得到的氯铂酸溶液，通过浸渍法使钌离子吸附在刻蚀NiNC材料表面。
13、对步骤12得到的混合液进行2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
14、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至950℃并恒温碳化1小时，之后进行自然降温至室温。最终得到NiPtNC异核双原子金属氮碳催化剂。
图25为实施例5中，NiPtNC金属双原子材料的扫描电镜图(SEM)。
图26为实施例5中，NiPtNC金属双原子材料的透射电镜图(TEM)。在50纳米的标尺下，没有出现金属镍或铂的纳米颗粒。
图27为实施例5中，NiPtNC金属双原子材料、步骤5得到的NiNC材料、步骤9得到的刻蚀NiPNC材料的X射线衍射图(XRD)。
图26和图27证明NiPtNC金属双原子材料中没有金属镍和金属铂的纳米颗粒。
图28为在0.1M KOH的碱性条件下，NiPtNC金属双原子材料与各单金属催化剂(步骤5得到的NiNC材料、步骤9得到的刻蚀NiPtNC材料)的线性扫描曲线比较。NiPtNC金属双原子材料的半波电位为0.812V。步骤5得到的NiNC材料的半波电位为0.707V、步骤9得到的刻蚀NiPtNC材料的半波电位为0.717V。这说明NiPtNC金属双原子材料在碱性条件下氧还原催化活性优于步骤5得到的NiNC材料、步骤9得到的刻蚀NiPtNC材料。
实施例6：
CoIrNC金属双原子材料的制备方法如下：
1、将30mL甲酰胺作为溶剂溶解钴盐和锌盐，超声30分钟直至两种盐类充分溶解与甲酰胺中，得到的均一的水热反应母液A；钴盐和锌盐的摩尔比为1:10， 上述钴盐为无水氯化钴，锌盐为无水氯化锌。水热反应母液A中，无水氯化钴的浓度为0.005mol/L，无水氯化锌的浓度为0.1mol/L。
2、将上述母液A倒入清洁干燥的密闭反应釜中，在180℃下水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在900℃的温度下恒温碳化2小时，待恒温结束后自然冷却至室温，制得钴单原子氮碳材料(CoNC)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合得到混合溶液，将上述合成的50mg钴氮碳材料溶于上述混合溶液中，超声1小时直至其分散均匀，得到混合溶液D。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加0.25mL的10mol/L的过氧碳酸盐溶液，得混合均匀的反应液E。
8、将反应液E转移到高压反应釜中，置于150℃烘箱中，反应3小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的钴单原子氮碳材料(刻蚀CoNC)。
10、称取50mg的刻蚀CoNC材料的干燥固体，将其溶解于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，超声1小时后，转移到恒温搅拌台上，得到刻蚀CoNC的水醇溶液。
11、移取取适量的氯铱酸溶于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，并超声至分散均一，得到10mg/mL(0.0194mol/L)的氯铱酸溶液。
12、将步骤10得到的刻蚀CoNC的水醇溶液在剧烈搅拌2小时下，均匀滴加入步骤11得到的氯铱酸溶液，通过浸渍法使钌离子吸附在刻蚀CoNC材料表面。
13、对步骤12得到的混合液进行2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
14、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至950℃并恒温碳化1小时，之后进行自然降温至室温。最终得到CoIrNC异核双原子金属氮碳催化剂。
图29为实施例6中，CoIrNC金属双原子材料的扫描电镜图(SEM)。
图30为实施例6中，CoIrNC金属双原子材料的透射电镜图(TEM)。在50纳米的标尺下，没有出现金属钴或铱的纳米颗粒。
图31为实施例6中，CoIrNC金属双原子材料、步骤5得到的CoNC材料、步骤9得到的刻蚀CoNC材料的X射线衍射图(XRD)。
图30和图31证明CoIrNC金属双原子材料没有金属钴和金属铱的纳米颗粒。
图32在0.1M KOH的碱性条件下，CoIrNC金属双原子材料与各单金属催化剂(步骤5得到的CoNC材料、步骤9得到的刻蚀CoNC材料)的线性扫描曲线比较。CoIrNC金属双原子材料的半波电位为0.885V，远高于CoNC材料(半波电位为0.801V)和刻蚀CoNC材料(半波电位为0.793V)的半波电位。这说明CoIrNC金属双原子材料的电催化氧还原活性优于步骤5得到的CoNC材料、步骤9得到的刻蚀CoNC材料。
实施例7：
MnRuNC金属双原子材料的制备方法如下：
根据实施例3的方法，只把步骤1的金属钴替换为锰，步骤11的钴替换为钌，其余步骤相同。步骤14可得到的MnRuNC金属双原子材料。
其中，步骤5可得到锰单原子氮碳材料，即MnNC。步骤9可得到刻蚀后的刻蚀MnNC材料。
图33为MnRuNC金属双原子材料的扫描电镜图(SEM)。
图34为在0.1M KOH的碱性条件下，MnRuNC金属双原子材料、MnNC和刻蚀MnNC的线性扫描曲线比较。MnRuNC金属双原子材料的半波电位为 0.788V，高于MnNC材料(半波电位为0.757V)和刻蚀MnNC材料(半波电位为0.723V)的半波电位。这说明MnRuNC金属双原子材料的电催化氧还原活性优于MnNC材料和刻蚀MnNC材料。
实施例8：
MnPtNC金属双原子材料的制备方法如下：
根据实施例3的方法，只把步骤1的金属钴替换为锰，步骤7中的过氧乙酸盐替换为过氧二硫酸盐，步骤11的钴替换为铂，其余步骤相同，即可得到的MnPtNC金属双原子材料。
其中，步骤5可得到锰单原子氮碳材料，即MnNC。步骤9可得到刻蚀后的刻蚀MnNC材料。
图35为MnPtNC金属双原子材料的扫描电镜图(SEM)。
图36为在0.1M KOH的碱性条件下，MnPtNC金属双原子材料、MnNC和刻蚀MnNC的线性扫描曲线比较。MnPtNC金属双原子材料的半波电位为0.844V，高于MnNC材料(半波电位为0.774V)和刻蚀MnNC材料(半波电位为0.734V)的半波电位。这说明MnPtNC金属双原子材料的电催化氧还原活性优于MnNC材料和刻蚀MnNC材料。
实施例9：
NiAuNC金属双原子材料的制备方法如下：
根据实施例3的方法，只把步骤1的金属钴替换为镍，步骤11的钴替换为金，其余步骤相同，即可得到的NiAuNC金属双原子材料。
其中，步骤5可得到镍单原子氮碳材料，即NiNC。步骤9可得到刻蚀后的刻蚀NiNC材料。
图37为NiAuNC金属双原子材料的扫描电镜图(SEM)。
图38为在0.1M KOH的碱性条件下，NiAuNC金属双原子材料、NiNC和刻蚀NiNC的线性扫描曲线比较。NiAuNC金属双原子材料的半波电位为0.786V，高于NiNC材料(半波电位为0.707V)和刻蚀NiNC材料(半波电位为0.717V)的半波电位。这说明NiAuNC金属双原子材料的电催化氧还原活性优于NiNC材料和刻蚀NiNC材料。
实施例10：
NiAgNC金属双原子材料的制备方法如下：
根据实施例3的方法，只把步骤1的金属钴替换为镍，步骤11的钴替换为银，其余步骤相同。即可得到的NiAgNC金属双原子材料。
其中，步骤5可得到镍单原子氮碳材料，即NiNC。步骤9可得到刻蚀后的刻蚀NiNC材料。
图39为NiAgNC金属双原子材料的扫描电镜图(SEM)。
图40为在0.1M KOH的碱性条件下，NiAuNC金属双原子材料、NiNC和刻蚀NiNC的线性扫描曲线比较。NiAgNC金属双原子材料的半波电位为0.807V，高于NiNC材料(半波电位为0.707V)和刻蚀NiNC材料(半波电位为0.717V)的半波电位。这说明NiAgNC金属双原子材料的电催化氧还原活性优于NiNC材料和刻蚀NiNC材料。
实施例11：
FeRuSNC金属双原子材料的制备方法如下：
1、将30mL甲酰胺作为溶剂溶解铁盐、锌盐和硫脲，超声30分钟直至两种盐类充分溶解与甲酰胺中，得到的均一红褐色溶液为水热反应母液A；铁盐和锌盐的摩尔比为1:20，上述铁盐为乙酰丙酮铁，锌盐为无水氯化锌。水热反应母液A中，乙酰丙酮铁的浓度为0.005mol/L，无水氯化锌的浓度为0.2mol/L。
2、将上述母液A倒入清洁干燥的密闭反应釜中，在180℃下水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在900℃的温度下恒温碳化2小时，待恒温结束后自然冷却至室温，制得铁单原子硫氮碳材料(FeSNC)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合成溶液，将上述合成的50mg铁硫氮碳材料溶于混合溶液D中，超声1小时直至其分散均匀。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加0.25mL的质量分数为30％(10mol/L)的过氧化氢溶液，得混合均匀的反应液E。
8、将反应液E转移到高压反应釜中，置于110℃烘箱中，反应3小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的铁单原子氮碳材料(刻蚀FeSNC)。
10、称取50mg的刻蚀FeSNC材料的干燥固体，将其溶解于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，超声1小时后，转移到恒温搅拌台上，得到刻蚀FeSNC的水醇溶液。
11、称取适量的氯化钌粉末溶于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，并超声至溶解，得到10mg/mL(即0.048mol/L)的氯化钌溶液。
12、将步骤10得到的刻蚀FeSNC的水醇溶液在剧烈搅拌2小时下，均匀滴加入步骤11得到的氯化钌溶液得到混合液，通过浸渍法使钌离子吸附在刻蚀FeSNC材料表面。混合液中，刻蚀FeSNC材料的浓度为1mg/mL，氯化钌溶液的浓度为0.024mol/L。
13、对步骤12得到的混合液进行2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
14、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至950℃并恒温碳化1小时，之后进行自然降温至室温。最终得到FeRuSNC异核双原子金属硫氮碳催化剂。
图41为实施例11中，FeRuSNC金属双原子材料的扫描电镜图(SEM)。
图42为实施例11中，FeRuSNC金属双原子材料的透射电镜图(TEM)。在50纳米的标尺下，没有出现金属铁或钌的纳米颗粒。
图43为实施例11中，FeRuSNC金属双原子材料、步骤5得到的FeNC、步骤9得到的刻蚀FeSNC的X射线衍射图(XRD)。
图42和图43证明FeRuSNC金属双原子材料中没有金属铁和金属钌的纳米 颗粒。
图44为在0.1M KOH的碱性条件下，FeRuSNC金属双原子材料与各单金属催化剂(步骤5得到的FeSNC、步骤9得到的刻蚀FeSNC)的线性扫描曲线比较。FeRuSNC金属双原子材料的半波电位为0.878V。步骤5得到的FeSNC的半波电位为0.833V、步骤9得到的刻蚀FeSNC的半波电位为0.813V。这说明FeRuSNC金属双原子材料电催化氧还原活性优于步骤5得到的FeSNC、步骤9得到的刻蚀FeSNC。
上述实施例仅以几种金属元素作为举例说明，可以预想，本申请公开的其他金属元素也具有相同的效果。
实施例12～17的具体条件如下：
实施例12
铁铂氮碳材料的制备方法包括以下步骤：
1、将30mL甲酰胺作为溶剂溶解铁盐和锌盐，超声30分钟以确保两种盐类充分溶解于甲酰胺中，得到的均一暗红色溶液为水热反应母液A；铁盐和锌盐的摩尔比为1:10，上述铁盐为乙酰丙酮铁，摩尔数为0.005mol/L。锌盐为无水氯化锌，摩尔数为0.1mol/L。
2、将上述水热反应母液A倒入清洁干燥的密闭反应釜中，在180℃水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，直至得到干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在900℃的温度下恒温碳化2小时，待恒温结束后自然冷却至室温，制得铁单原子氮碳材料(FeNC-1)。
6、分别量取相同体积的乙醇和去离子水各15mL，混合成溶液，将上述合成的60mg铁单原子氮碳材料(FeNC-1)溶于混合溶液D中，超声30分钟后直至其分散均匀。得到的铁单原子氮碳材料的浓度是2mg/mL。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加质量分数为30％的过氧化氢溶液0.30mL，得混合均匀的反应液E。反应液E中，过氧化氢的浓度是0.1mol/L，铁单原子氮碳材料的浓度是2mg/mL。
8、将反应液E转移到高压反应釜中，置于110℃烘箱中，反应3小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的铁单原子氮碳材料(刻蚀FeNC-1)。
10、称取50mg的刻蚀FeNC-1材料的干燥固体，将其溶解于等体积的25mL无水乙醇和25mL去离子水的混合溶液中，超声1小时后，转移到恒温搅拌台上，得到刻蚀FeNC-1的的水醇溶液。
11、在步骤10得到的刻蚀FeNC-1的水醇溶液中均匀滴加入氯铂酸溶液(1.05g/ml)17.5μL得到混合液，室温下剧烈搅拌2小时，通过浸渍法使铂离子吸附在刻蚀FeNC-1材料表面。得到混合液中，刻蚀FeNC-1的浓度为1mg/mL，
氯铂酸的浓度为0.0009mol/L
12、2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
13、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至950℃并恒温碳化1小时，之后进行自然降温至室温。最终得到异核双原子金属氮碳催化剂(FePtNC-1)。
第一、对上述材料进行表征：
图46为FePtNC的扫描电子显微镜(SEM)图片。
图46可见：扫描电子显微镜(SEM)观察到FePtNC双原子的形貌为无定形， 存在部分孔结构。
图47为FePtNC的透射电子显微镜(TEM)。
图47可见：透射电子显微镜(TEM)显示FePtNC双原子为薄片状，并呈现出多层堆叠的片状结构。
图48为FePtNC的高角环形暗场扫描透射电子显微镜(HAADF-STEM)图片。
图48证实了FePtNC双原子。图片中的亮点代表金属原子，其中大多都是以两个铁铂原子对的形式出现在图片中，证明材料为FePtNC双原子。
通过直接测量分析方法，对双原子之间的距离进行测量，双原子之间的距离统计如下表1。
表1
上表1证明，所有双原子之间的距离小于或等于0.5nm，即铁单原子和铂单原子之间的距离小于或等于0.5纳米，具体为0.14～0.5nm。
且图48可见，在2纳米的标尺下，即158.24平方纳米下有双金属原子对有15对，原子对的密度更高，表明这种FePtNC双原子材料和制备方法具有独特的优越性，该方法制备的双金属原子对的成功率更高。
参考文献2的图1d为PtFeNC双金属原子催化剂的高角环形暗场扫描透射图。由参考文献2中的图1d可见，在5纳米的标尺下，1126.388平方纳米下，有15对双金属原子，原子对的数目较少。图48与参考文献2的图1d相比，证明了本发明的材料双原子位点更多。这证明：在氮碳材料的导电基底上，双原子成功概率大于一锅水热法制备的双金属原子。
图48和参考文献2的图1d中，图片的面积，由发明人根据图片中的标尺和图片实际大小通过计算换算得到。
图49为FePtNC-1、FeNC-1和刻蚀FeNC-1的X射线衍射(XRD)图。
图49的X射线衍射(XRD)显示FePtNC-1双原子材料仅在25°和43°处呈现 出两个衍射峰，分别为石墨碳的(002)和(100)平面，并且没有出现金属铁和金属铂纳米颗粒的衍射峰，所以在合成的系列材料中不含有金属颗粒。铁和铂均呈单原子分散状态。
第二、性能测试：
对上述得到的FePtNC-1进行性能测试，测试条件是采用CHI三电极体系，在O2饱和的0.1M KOH和1600rmp转速下进行线性扫描(LSV)测试。
图50为FePtNC-1双金属原子催化剂、FeNC-1和刻蚀FeNC-1、20wt％Pt/C材料在1600rmp下的氧还原的线性扫描极化曲线
图50证明：在0.1M KOH碱性条件下，FePtNC-1双原子的半波电位为0.905V，远优于单原子级别的FeNC-1、刻蚀FeNC-1和FeNC-1(FeNC-1的半波电位是0.853V，刻蚀FeNC的半波电位为0.842V)。
同时，FePtNC-1双原子的半波电位高于20wt％Pt/C的半波电位(为0.872V)33mV。
图50证明：因而加入第二种金属物种，形成双原子催化剂能大幅度提升单原子催化剂的氧还原性能，加速氧还原反应速率。
其中，20wt％Pt/C材料是Pt质量含量为20％的Pt/C材料，可以市场购买获得。
刻蚀FeNC-1来源是按实施例1中的制备过程制备，步骤9得到的产物。
FeNC-1来源是按实施例1中的制备过程制备，步骤5得到的产物。
图51为FePt双金属原子催化剂材料的四电子转移数和过氧化氢产率。
图51证明：通过实验数据计算，FePtNC-1双原子的电子转移数为4，很接近4电子转移数。同时，过氧化氢在宽的电势范围内的产率低于1％，表明FePtNC-1双原子的4电子选择性高。图51中，20wt％Pt/C材料作为对比材料，和FePtNC-1进行对比，来表明FePtNC-1双原子的电催化氧还原性能优异。
将FePtNC-1双原子催化剂和20wt％Pt/C材料在氧气饱和的0.1M KOH碱性条件下进行测试。图52为FePtNC-1双金属原子催化剂和20wt％Pt/C材料工作10000圈前后的氧还原极化曲线。图52表明FePtNC-1双原子在经过10000圈的循环后，半波电位仅负移了8mV，活性衰减可忽略。而20wt％Pt/C的半波电位则出现了明显的衰减。
实施例13
铁铂氮碳材料的制备方法包括以下步骤：
1、将30mL甲酰胺作为溶剂溶解铁盐和锌盐，超声30分钟以确保两种盐类充分溶解于甲酰胺中，得到的均一暗红色溶液为水热反应母液A；铁盐和锌盐的摩尔比为1:4，上述铁盐为无水氯化铁，摩尔数为0.005mol/L。锌盐为无水氯化锌，摩尔数为0.2mol/L。
2、将上述水热反应母液A倒入清洁干燥的密闭反应釜中，在160℃水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，直至得到干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在800℃的温度下恒温碳化4小时，待恒温结束后自然冷却至室温，制得铁单原子氮碳材料(FeNC-2)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合成溶液，将上述合成的50mg铁单原子氮碳材料(FeNC-2)溶于混合溶液D中，超声30分钟后直至其分散均匀。得到的铁单原子氮碳材料的浓度是2mg/mL。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加10mol/L的过氧二硫酸盐溶液0.126mL，得混合均匀的反应液E。反应液E中过氧二硫酸盐浓度为0.05mol/L，铁单原子氮碳材料的浓度是2mg/mL。
8、将反应液E转移到高压反应釜中，置于150℃烘箱中，反应5小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的铁单原子氮碳材料(刻蚀FeNC-2)。
10、称取50mg的刻蚀FeNC-2材料的干燥固体，将其溶解于等体积的25mL无水乙醇和25mL去离子水的混合溶液中。
11、超声1小时后，转移到恒温搅拌台上，均匀滴加入氯铂酸溶液(1.05g/ml)17.5μL得到混合液，室温下剧烈搅拌2小时，通过浸渍法使铂离子吸附在刻蚀FeNC-2材料表面。得到混合液中，刻蚀FeNC-1的浓度为1mg/mL，氯铂酸的浓度为0.0009mol/L。
12、2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
13、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至950℃并恒温碳化1小时，之后进行自然降温至室温。最终得到异核双原子金属氮碳催化剂(FePtNC-2)。
材料表征和性能测试如下：
图53为实施例13的FePtNC-2双原子材料的扫描电子显微镜(SEM)图。
图54为实施例13步骤13得到的FePtNC-2、步骤9得到的FeNC-2、步骤5得到的刻蚀FeNC-2的X射线衍射(XRD)图。图54可见仅有2个碳峰，表明在FeNC-2、刻蚀FeNC-2和FePtNC-2中没有金属纳米颗粒。
图55为实施例13的FePtNC-2双原子材料的高角环形暗场扫描透射电子显微镜(HAADF-STEM)图片。由图55可见，在2纳米的标尺下，即112平方纳米下有双金属原子对有21对，即0.18对/平方纳米，原子对的密度更高。这表明这种FePtNC双原子材料和制备方法具有独特的优越性，该方法制备的双金属原子对的成功率更高。
图56为实施例13的FePtNC-2双原子材料、步骤5得到的FeNC-2、步骤9得到的刻蚀FeNC-2在O2饱和的0.1M KOH的碱性条件，转速1600rmp下的氧还原的线性扫描极化曲线。图56可见，FePtNC-2双原子材料的半波电位为0.887V，而FeNC-2的半波电位为0.860V，刻蚀FeNC-2的半波电位为0.812V。对比分析发现，FePtNC-2的半波电位最大，表明其电催化氧还原活性最佳。这说明，在电催化氧还原反应中，铁单原子和铂单原子具有协同作用，铁铂双原子的催化活性高于铁单原子。
实施例14
铁铂氮碳材料的制备方法包括以下步骤：
1、将30mL甲酰胺作为溶剂溶解铁盐和锌盐，超声30分钟以确保两种盐类 充分溶解于甲酰胺中，得到的均一暗红色溶液为水热反应母液A；铁盐和锌盐的摩尔比为1:20，上述铁盐为无水氯化铁，摩尔数为0.005mol/L。锌盐为无水氯化锌，摩尔数为0.2mol/L。
2、将上述水热反应母液A倒入清洁干燥的密闭反应釜中，在220℃水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，直至得到干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在1100℃的温度下恒温碳化6小时，待恒温结束后自然冷却至室温，制得铁单原子氮碳材料(FeNC-3)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合成溶液，将上述合成的100mg铁单原子氮碳材料(FeNC-3)溶于混合溶液D中，超声30分钟后直至其分散均匀。得到的铁单原子氮碳材料的浓度是4mg/mL。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加10mol/L的过硫酸钠溶液2.5mL，得混合均匀的反应液E。反应液E中过硫酸钠的浓度为1.0mol/L，铁单原子氮碳材料的浓度是4mg/mL。
8、将反应液E转移到高压反应釜中，置于200℃烘箱中，反应8小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的铁单原子氮碳材料(刻蚀FeNC-3)。
10、称取100mg的刻蚀FeNC-3材料的干燥固体，将其溶解于等体积的25mL无水乙醇和25mL去离子水的混合溶液中。
11、超声1小时后，转移到恒温搅拌台上，均匀滴加入氯铂酸溶液(1.05g/ml)35μL得到混合液，室温下剧烈搅拌2小时，通过浸渍法使铂离子吸附在刻蚀FeNC-3材料表面。得到混合液中，刻蚀FeNC-1的浓度为2mg/mL，氯铂酸的浓 度为0.0018mol/L。
12、2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
13、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至950℃并恒温碳化1小时，之后进行自然降温至室温。最终得到异核双原子金属氮碳催化剂(FePtNC-3)。
材料表征和性能测试如下：
图57为实施例14的FePtNC-3双原子材料的扫描电子显微镜(SEM)图。
图58为实施例14步骤13得到的FePtNC-3、步骤9得到的FeNC-3、步骤5得到的刻蚀FeNC-3的X射线衍射(XRD)图。图58可见仅有2个碳峰，表明在FeNC-3、刻蚀FeNC-3和FePtNC-3中没有金属纳米颗粒。
图59为实施14的FePtNC-3双原子材料、步骤5得到的FeNC-3、步骤9得到的刻蚀FeNC-3在O2饱和的0.1M KOH的碱性条件，转速为1600rmp下的氧还原的线性扫描极化曲线。图59可见，FePtNC-3双原子材料的半波电位为0.884V，而FeNC-3的半波电位为0.855V，刻蚀FeNC-3的半波电位为0.837V。对比分析发现，FePtNC-3的半波电位最大，表明其电催化氧还原活性最佳。这说明，在电催化氧还原反应中，铁单原子和铂单原子具有协同作用，铁铂双原子的催化活性高于铁单原子。
实施例15
铂铁硫氮碳材料的制备方法包括以下步骤：
1、将30mL甲酰胺作为溶剂溶解铁盐、锌盐和硫源，超声30分钟以确保两种盐类充分溶解于甲酰胺中，得到的均一暗红色溶液为水热反应母液A；铁盐、锌盐和硫源的摩尔比为1:10:2，上述铁盐为无水氯化铁，摩尔数为0.005mol/L。锌盐为无水氯化锌，摩尔数为0.1mol/L。上述硫源为硫脲，摩尔数为0.01mol/L
2、将上述水热反应母液A倒入清洁干燥的密闭反应釜中，在180℃水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，直至得到干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在900℃的温度下恒温碳化2小时，待恒温结束后自然冷却至室温，制得铁单原子氮碳材料(FeSNC-1)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合成溶液，将上述合成的50mg铁单原子氮碳材料(FeSNC-1)溶于混合溶液D中，超声30分钟后直至其分散均匀。得到的铁单原子氮碳材料的浓度是2mg/mL。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加质量分数为30％的过氧化氢溶液0.30mL，得混合均匀的反应液E。反应液E中，过氧化氢的浓度为0.1mol/L，铁单原子氮碳材料的浓度是2mg/mL。
8、将反应液E转移到高压反应釜中，置于110℃烘箱中，反应3小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的铁单原子氮碳材料(刻蚀FeSNC-1)。
10、称取50mg的刻蚀FeSNC-1材料的干燥固体，将其溶解于等体积的25mL无水乙醇和25mL去离子水的混合溶液中。
11、超声1小时后，转移到恒温搅拌台上，均匀滴加入氯铂酸溶液(1.05g/ml)17.5μL得到混合液，室温下剧烈搅拌2小时，通过浸渍法使铂离子吸附在刻蚀FeSNC-1材料表面。得到混合液中，刻蚀FeNC-1的浓度为1mg/mL，氯铂酸的浓度为0.0009mol/L。
12、2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
13、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至950℃并恒温碳化1小时，之后进行自然降温至室温。最终得到异核双原子金属氮碳催化剂(FePtSNC-1)。
图60为FePtSNC-1的扫描电子显微镜(SEM)图片。
图61为FePtSNC-1、FeSNC-1和刻蚀FeSNC-1的X射线衍射(XRD)图。
图62为实施例2的FePtSNC-1双金属原子催化剂、步骤5得到的FeSNC-1、步骤9得到的刻蚀FeSNC-1在O2饱和的0.1M KOH的碱性条件，转速为1600rmp下的氧还原的线性扫描极化曲线。图62可见FePtSNC-1的半波电位为0.892V，FeSNC-1的半波电位为0.852V，刻FeSNC-1的半波电位为0.835V。对比分析发现，FePtSNC-1的半波电位最大，表明其电催化氧还原活性最佳。这说明，在电催化氧还原反应中，铁单原子和铂单原子具有协同作用，铁铂双原子的催化活性高于铁单原子。
实施例16
铂铁硫氮碳材料的制备方法包括以下步骤：
1、将30mL甲酰胺作为溶剂溶解铁盐、锌盐和硫源，超声30分钟以确保两种盐类充分溶解于甲酰胺中，得到的均一暗红色溶液为水热反应母液A；铁盐、锌盐和硫源的摩尔比为1:4:2，上述铁盐为无水氯化铁，摩尔数为0.005mol/L。锌盐为无水氯化锌，摩尔数为0.2mol/L。上述硫源为硫脲，摩尔数为0.01mol/L
2、将上述水热反应母液A倒入清洁干燥的密闭反应釜中，在160℃水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，直至得到干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在800℃的温度下恒温碳化4小时，待恒温结束后自然冷却至室温，制得铁单原子氮碳材料(FeSNC-2)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合成溶液，将上述合成的50mg铁单原子氮碳材料(FeSNC-2)溶于混合溶液D中，超声30分钟后直至其分散均匀。得到的铁单原子氮碳材料的浓度是2mg/mL。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加10mol/L的过氧二硫酸盐溶液0.126mL，得混合均匀的反应液E。反应液E中过氧 二硫酸盐浓度为0.05mol/L。
8、将反应液E转移到高压反应釜中，置于150℃烘箱中，反应5小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的铁单原子氮碳材料(刻蚀FeSNC-2)。
10、称取50mg的刻蚀FeSNC-2材料的干燥固体，将其溶解于等体积的25mL无水乙醇和25mL去离子水的混合溶液中。
11、超声1小时后，转移到恒温搅拌台上，均匀滴加入氯铂酸溶液(1.05g/ml)17.5μL得到混合液，室温下剧烈搅拌2小时，通过浸渍法使铂离子吸附在刻蚀FeSNC-2材料表面。得到混合液中，刻蚀FeNC-1的浓度为1mg/mL，氯铂酸的浓度为0.0009mol/L。
12、2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
13、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至950℃并恒温碳化1小时，之后进行自然降温至室温。最终得到异核双原子金属氮碳催化剂(FePtSNC-2)。
材料表征和性能测试如下：
图63为实施例16的FePtSNC-2双原子材料的扫描电子显微镜(SEM)图。
图64为实施例16步骤13得到的FePtNC-2、步骤9得到的FeSNC-2、步骤2得到的刻蚀FeSNC-2的X射线衍射(XRD)图。图64可见仅有2个碳峰，表明在FeSNC-5、刻蚀FeNC-2和FePtNC-2中没有金属纳米颗粒。
图65为实施例16的FePtSNC-2双金属原子材料、步骤5得到的FeSNC-2、步骤9得到的刻蚀FeSNC-2在O2饱和的0.1M KOH的碱性条件，转速为1600rmp下的氧还原的线性扫描极化曲线。图65可见，FePtSNC-2双原子材料的半波电位为0.897V，而FeSNC-2的半波电位为0.855V，刻蚀FeSNC-2的半波电位为0.844V。对比分析发现，FePtSNC-2的半波电位最大，表明其电催化氧还原活性最佳。这说明，在电催化氧还原反应中，铁单原子和铂单原子具有协同作用，铁铂双原子的催化活性高于铁单原子。
实施例17
铂铁硫氮碳材料的制备方法包括以下步骤：
1、将30mL甲酰胺作为溶剂溶解铁盐、锌盐和硫源，超声30分钟以确保两种盐类充分溶解于甲酰胺中，得到的均一暗红色溶液为水热反应母液A；铁盐、锌盐和硫源的摩尔比为1:20:2，上述铁盐为无水氯化铁，摩尔数为0.005mol/L。锌盐为无水氯化锌，摩尔数为0.2mol/L。上述硫源为硫脲，摩尔数为0.01mol/L
2、将上述水热反应母液A倒入清洁干燥的密闭反应釜中，在220℃水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，直至得到干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在1100℃的温度下恒温碳化6小时，待恒温结束后自然冷却至室温，制得铁单原子氮碳材料(FeSNC-3)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合成溶液，将上述合成的50mg铁单原子氮碳材料(FeSNC-3)溶于混合溶液D中，超声30分钟后直至其分散均匀。得到的铁单原子氮碳材料的浓度是2mg/mL。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加10mol/L的过硫酸钠溶液2.5mL，得混合均匀的反应液E。反应液E中过硫酸钠的浓度为1.0mol/L。
8、将反应液E转移到高压反应釜中，置于200℃烘箱中，反应8小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的铁单原子氮碳材料(刻蚀FeSNC-3)。
10、称取50mg的刻蚀FeSNC-3材料的干燥固体，将其溶解于等体积的25mL无水乙醇和25mL去离子水的混合溶液中。
11、超声1小时后，转移到恒温搅拌台上，均匀滴加入氯铂酸溶液(1.05g/ml) 17.5μL得到混合液，室温下剧烈搅拌2小时，通过浸渍法使铂离子吸附在刻蚀FeSNC-3材料表面。得到混合液中，刻蚀FeNC-1的浓度为1mg/mL，氯铂酸的浓度为0.0009mol/L。
12、2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
13、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至950℃并恒温碳化1小时，之后进行自然降温至室温。最终得到异核双原子金属氮碳催化剂(FePtSNC-3)。
材料表征和性能测试如下：
图66为实施例17的FePtSNC-3双原子材料的扫描电子显微镜(SEM)图。
图67为实施例17步骤13得到的FePtSNC-3、步骤9得到的FeSNC-3、步骤6得到的刻蚀FeSNC-3的X射线衍射(XRD)图。图67可见仅有2个碳峰，表明在FeSNC-3、刻蚀FeSNC-3和FePtSNC-3中没有金属纳米颗粒。
图68为实施例17的FePtSNC-3双金属原子材料、步骤5得到的FeSNC-3、步骤9得到的刻蚀FeSNC-3在O2饱和的0.1M KOH的碱性条件，转速为1600rmp下的氧还原的线性扫描极化曲线。图68可见，FePtSNC-3双原子材料的半波电位为0.861V，而FeSNC-3的半波电位为0.833V，刻蚀FeSNC-3的半波电位为0.824V。对比分析发现，FePtSNC-3的半波电位最大，表明其电催化氧还原活性最佳。这说明，在电催化氧还原反应中，铁单原子和铂单原子具有协同作用，铁铂双原子的催化活性高于铁单原子。
实施例18～20具体条件如下：
实施例18
钴铁金属双原子材料的制备方法包括以下步骤：
1、将30mL甲酰胺作为溶剂溶解钴盐和锌盐，超声30分钟以确保两种盐类充分溶解于甲酰胺中，得到的澄清粉色溶液为水热反应母液A；钴盐和锌盐的摩尔比为1:10，上述钴盐为无水氯化钴，摩尔数为0.01mol/L。锌盐为无水氯化锌，摩尔数为0.1mol/L。
2、将上述水热反应母液A倒入清洁干燥的密闭反应釜中，在180℃水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，直至得到干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在900℃的温度下恒温碳化2小时，待恒温结束后自然冷却至室温，制得钴单原子氮碳材料(CoNC-1)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合成溶液，将上述合成的50mg钴单原子氮碳材料(CoNC-1)溶于混合溶液D中，超声30分钟后直至其分散均匀。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加质量分数为30％(10mol/L)的过氧化氢溶液0.250mL，得混合均匀的反应液E。反应液E中过氧化氢浓度为0.1mol/L。
8、将反应液E转移到高压反应釜中，置于180℃烘箱中，反应6小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的钴单原子氮碳材料(刻蚀CoNC-1)。
10、称取50mg的刻蚀CoNC-1材料的干燥固体，将其溶解于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中。
11、超声1小时后，转移到恒温搅拌台上，并称取三氯化铁粉末0.1086g(即 0.75mgFe/mL)溶于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，并超声至溶解。
12、刻蚀CoNC-1的水醇溶液在剧烈搅拌2小时下，均匀滴加入三氯化铁溶液，通过浸渍法使铁离子吸附在刻蚀CoNC-1材料表面。
13、2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
14、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至900℃并恒温碳化1小时，之后进行自然降温至室温。最终得到异核双原子金属氮碳催化剂(CoFeNC-1)。
第一、对上述材料进行表征：
图69为CoFeNC-1的扫描电子显微镜(SEM)图片。
图69可见：扫描电子显微镜(SEM)观察到CoFeNC双原子的形貌为无定形，存在部分孔结构。
图70为CoFeNC-1的透射电子显微镜(TEM)。
图70可见：透射电子显微镜(TEM)显示CoFeNC-1双原子为薄片状，并呈现出多层堆叠的片状结构。
图71为CoFeNC-1的高角环形暗场扫描透射电子显微镜(HAADF-STEM)图片。
图71证实了CoFeNC-1双原子。图片中的亮点代表金属原子，其中大多都是以两个钴铁原子对的形式出现在图片中，证明材料为钴铁金属双原子材料。
通过直接测量分析方法，对双原子之间的距离进行测量，双原子之间的距离统计如下表1。
表1

上表1证明，所有双原子之间的距离小于或等于0.5nm，即钴单原子和铁单原子之间的距离小于或等于0.5纳米，具体为0.15～0.5nm。
且图71可见，在2纳米的标尺下，即280平方纳米下有双金属原子对有29对，原子对的密度更高，表明这种CoFeNC双原子材料和制备方法具有独特的优越性，该方法制备的双金属原子对的成功率更高。
图1为参考文献1中，Fe1Co1-CNF双金属原子催化剂的高角环形暗场扫描透射图。由图1可见，在2纳米的标尺下，156.11平方纳米下，有9对双金属原子，原子对的数目较少。图71与图1相比，证明了本发明的材料双原子位点更多。这证明：在氮碳材料的导电基底上，双原子成功概率大于一锅水热法制备的双金属原子。
图71和图1中，图片的面积，由发明人根据图片中的标尺和图片实际大小通过计算换算得到。
图72为CoFeNC-1、CoNC-1和刻蚀CoNC-1的X射线衍射(XRD)图。
图72的X射线衍射(XRD)显示CoFeNC-1双原子材料仅在25°和43°处呈现出两个衍射峰，分别为石墨碳的(002)和(100)平面，并且没有出现金属钴和金属铁纳米颗粒的衍射峰，所以在合成的系列材料中不含有金属颗粒，钴和铁均呈单原子分散状态。
图72中的CoNC-1和刻蚀CoNC-1的X射线衍射(XRD)图仅有2个碳峰，表明在CoNC-1和刻蚀CoNC-1中没有金属钴纳米颗粒，钴呈单原子分散状态。
第二、性能测试：
对上述得到的CoFeNC-1进行性能测试，测试条件是采用CHI三电极体系，在O2饱和的0.1M KOH和1600rmp转速下进行线性扫描(LSV)测试。
图73为CoFeNC-1双原子材料、刻蚀CoNC-1、FeNC、CoNC-1、20wt％Pt/C材料在1600rmp下的氧还原的线性扫描极化曲线。图73证明：在0.1M KOH碱 性条件下，CoFeNC-1双原子材料的半波电位为0.897V，远优于单原子级别的CoNC-1、刻蚀CoNC-1和FeNC(刻蚀CoNC-1的半波电位是0.793V，CoNC-1的半波电位为0.801V，FeNC的半波电位为0.864V)。同时，CoFeNC-1双原子材料的半波电位高于20wt％Pt/C的半波电位(为0.872V)25mV。图73证明：因而加入第二种金属物种，形成双原子催化剂能大幅度提升单原子催化剂的氧还原性能，加速氧还原反应速率。图73中，20wt％Pt/C材料是Pt质量含量为20％的Pt/C材料，可以市场购买获得。刻蚀CoNC-1来源是按实施例18中的制备过程制备，步骤9得到的产物。CoNC-1来源是按实施例18中的制备过程制备，步骤5得到的产物。FeNC的制备方法如下：FeNC的制备与实施例18中，1-5步骤中CoNC-1的制备一致，仅需把钴盐更换为铁盐，即乙酰丙酮铁，其摩尔浓度为0.005mol/L。制备得到的材料为FeNC。
图74为CoFeNC-1双原子材料和20wt％Pt/C材料的四电子转移数和过氧化氢产率。图74证明：通过实验数据计算，CoFeNC-1双原子材料的电子转移数为3.99，很接近4电子转移数。同时，过氧化氢在宽的电势范围内的产率低于1％，表明CoFeNC-1双原子材料的4电子选择性高。图74中，20wt％Pt/C材料作为对比材料，和CoFeNC-1双原子材料进行对比，来表明CoFeNC-1双原子材料的电催化氧还原性能优异。
将CoFeNC-1双原子材料和20wt％Pt/C材料在氧气饱和的0.1M KOH碱性条件下进行测试。图75为CoFeNC-1双原子材料和20wt％Pt/C材料工作40000秒前后的氧还原极化曲线。图75表明CoFeNC-1双原子材料在经过40000秒的循环后，半波电位仅负移了3mV(平均约10000秒的循环后，半波电位仅负移了0.75mV)，活性衰减可忽略。而20wt％Pt/C的半波电位则出现了明显的衰减。
图2为参考文献1中Fe1Co1-CNF双金属原子催化剂在0.5V电位下工作10000秒前后的氧还原极化曲线。Fe1Co1-CNF双金属原子催化剂的循环稳定性较差，在10000秒的CV循环后，其Fe1Co1-CNF双金属原子催化剂的半波电位负移了2mV(注：半波电位负移数值越小，循环时间越长，循环稳定性越高)。
对比图75和图2证明：本发明的CoFeNC-1双原子材料的循环稳定性高于参考文献的Fe1Co1-CNF双金属原子催化剂。
实施例19
钴铁金属双原子材料的制备方法包括以下步骤：
1、将30mL甲酰胺作为溶剂溶解钴盐和锌盐，超声30分钟以确保两种盐类充分溶解于甲酰胺中，得到的澄清粉色溶液为水热反应母液A；钴盐和锌盐的摩尔比为1:4，上述钴盐为硝酸钴，摩尔数为0.025mol/L。锌盐为无水氯化锌，摩尔数为0.1mol/L。
2、将上述水热反应母液A倒入清洁干燥的密闭反应釜中，在160℃水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，直至得到干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在800℃的温度下恒温碳化2小时，待恒温结束后自然冷却至室温，制得钴单原子氮碳材料(CoNC-2)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合成溶液，将上述合成的50mg钴单原子氮碳材料(CoNC-2)溶于混合溶液D中，超声30分钟后使其分散均匀。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加10mol/L的过氧二硫酸盐溶液0.126mL，得混合均匀的反应液E。反应液E中过氧化氢浓度为0.05mol/L。
8、将反应液E转移到高压反应釜中，置于150℃烘箱中，反应6小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀后的钴单原子氮碳材料(刻蚀CoNC-2)。
10、称取200mg的刻蚀CoNC-2材料的干燥固体，将其溶解于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中。
11、超声1小时后，转移到恒温搅拌台上，并称取等量三氯化铁粉末0.1839g(即1.27mgFe/mL)，溶于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，并超声至溶解。
12、刻蚀CoNC-2的水醇溶液在剧烈搅拌2小时下，均匀滴加入三氯化铁溶液，通过浸渍法使铁离子吸附在刻蚀CoNC-2材料表面。
13、2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
14、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至900℃并恒温碳化1小时，之后进行自然降温至室温。最终得到异核双原子金属氮碳催化剂-(CoFeNC-2)。
材料表征和性能测试如下：
图76为实施例19的CoFeNC-2双原子材料的扫描电子显微镜(SEM)图。
图77为实施例19步骤14得到的CoFeNC-2、步骤9得到的CoNC-2、步骤5得到的刻蚀CoNC-2的X射线衍射(XRD)图。图11可见仅有2个碳峰，表明在CoNC-2、刻蚀CoNC-2和CoFeNC-2中没有金属纳米颗粒。
图78为实施例19的CoFeNC-2双原子材料的高角环形暗场扫描透射电子显微镜(HAADF-STEM)图片。由图78可见，在2纳米的标尺下，即280平方纳米下有双金属原子对有44对，即0.16对/平方纳米，原子对的密度更高。这表明这种CoFeNC双原子材料和制备方法具有独特的优越性，该方法制备的双金属原子对的成功率更高。图片的面积，由发明人根据图片中的标尺和图片实际大小通过计算换算得到。
图79为实施例19的步骤14得到的CoFeNC-2双原子材料、步骤5得到的CoNC-2、步骤9得到的刻蚀CoNC-2、FeNC-2、20wt％Pt/C材料在O2饱和的0.1M KOH的碱性条件，转速1600rmp下的氧还原的线性扫描极化曲线。
FeNC-2的制备方法如下：FeNC-2的制备与实施例19中，1-5步骤中CoNC-2的制备一致，仅需把钴盐更换为铁盐，即乙酰丙酮铁，其摩尔浓度为0.005mol/L。制备得到的材料为FeNC-2。20wt％Pt/C材料是Pt质量含量为20％的Pt/C材料，可以市场购买获得。
图79可见，CoFeNC-2双原子材料的半波电位为0.885V，而CoNC-2的半波电位为0.802V，FeNC-2的半波电位为0.846V。对比发现，CoFeNC-2双原子材料的半波电位最大，同时高于20wt％Pt/C的半波电位(20wt％Pt/C的半波电位为0.872V)13mV，表明CoFeNC-2双原子材料的电催化氧还原性能最佳。
实施例20
钴铁金属双原子材料的制备方法包括以下步骤：
1、将30mL甲酰胺作为溶剂溶解钴盐和锌盐，超声30分钟以确保两种盐类充分溶解于甲酰胺中，得到的澄清粉色溶液为水热反应母液A；钴盐和锌盐的摩尔比为1:20，上述钴盐为无水硫酸钴，锌盐为无水氯化锌。
2、将上述水热反应母液A倒入清洁干燥的密闭反应釜中，在220℃水热反应12小时。
3、水热反应结束后，将密封反应釜自然冷却至室温，再打开反应釜并抽滤其反应液，同时用去离子水和无水乙醇各洗涤2次，得到无甲酰胺残留的固体材料B。
4、将固体材料B放入60℃的鼓风干燥箱内，烘干2小时，直至得到干燥的固体材料C。
5、将得到的固体材料C研磨成细粉末，并将该细粉末置于瓷舟内，在惰性气体N2保护下从室温开始，以5℃min-1的升温速率进行升温，再在1100℃的温度下恒温碳化2小时，待恒温结束后自然冷却至室温，制得钴单原子氮碳材料(CoNC-3)。
6、分别量取相同体积的乙醇和去离子水各12.5mL，混合成溶液，将上述合成的100mg钴单原子氮碳材料(CoNC-3)溶于混合溶液D中，超声30分钟后使其分散均匀。
7、将混合溶液D置于恒温搅拌台上搅拌10分钟，在搅拌期间均匀滴加10mol/L的过硫酸钠溶液2.5mL，得混合均匀的反应液E。反应液E中过硫酸钠的浓度为1.0mol/L。
8、将反应液E转移到高压反应釜中，置于200℃烘箱中，反应8小时。
9、反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤，再用去离子水洗涤三次，并置于真空冷冻干燥箱中进行过夜冷冻干燥处理，得到刻蚀 后的钴单原子氮碳材料(刻蚀CoNC-3)。
10、称取100mg的刻蚀CoNC-3材料的干燥固体，将其溶解于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中。
11、超声1小时后，转移到恒温搅拌台上，并称取等量三氯化铁粉末0.0460g(即0.3175mgFe/mL)，溶于等体积的12.5mL无水乙醇和12.5mL去离子水的混合溶液中，并超声至溶解。
12、刻蚀CoNC-3的水醇溶液在剧烈搅拌2小时下，均匀滴加入三氯化铁溶液，通过浸渍法使铁离子吸附在刻蚀CoNC-3材料表面。
13、2小时的搅拌结束后，对该混合液进行抽滤和洗涤，并将得到的固体材料进行真空冷冻干燥。
14、将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体Ar/N2的保护下，从室温开始升温，升温速度为5℃min-1，升温至900℃并恒温碳化1小时，之后进行自然降温至室温。最终得到异核双原子金属氮碳催化剂-(CoFeNC-3)。
图80为实施例20的CoFeNC-3的扫描电子显微镜(SEM)图。
图81为实施例20步骤14得到的CoFeNC-3、步骤5得到的CoNC-3、步骤9得到的刻蚀CoNC-3的X射线衍射(XRD)图。
图82为实施例20的CoFeNC-3双原子材料、步骤5得到的CoNC-3、步骤9得到的刻蚀CoNC-3在O2饱和的0.1M KOH的碱性条件，转速为1600rmp下的氧还原的线性扫描极化曲线。图82可见CoFeNC-3的半波电位为0.819V，CoNC-3的半波电位为0.788V，刻蚀CoNC-3的半波电位为0.784V。对比分析发现，CoFeNC-3的半波电位最大，表明其电催化氧还原活性最佳。这说明，在电催化氧还原反应中，钴单原子和铁单原子具有协同作用，钴铁双原子的催化活性高于钴单原子。

Claims (13)

  1. 一种金属双原子材料，其特征在于，所述金属双原子材料包含：导电基底和负载在所述导电基底上的第一金属单原子和第二金属单原子，其中第一金属单原子和第二金属单原子的距离小于或等于0.5纳米。
  2. 根据权利要求1所述的金属双原子材料，其特征在于，在导电基底上，双原子对的密度不小于0.06对/平方纳米。
  3. 根据权利要求1所述的金属双原子材料，其特征在于，所述第一金属单原子中的第一金属选自：钴、铁、锌、镍、锰、铂、钌、铱、金、银中的一种或几种；
    所述第二金属单原子中的第二金属选自：钴、铁、锌、镍、锰、铂、钌、铱、金、银中的一种或几种。
  4. 根据权利要求1所述的金属双原子材料，其特征在于，所述导电基底选自：氮碳材料或硫氮碳材料。
  5. 一种权利要求1～4所述的金属双原子材料的制备方法，其特征在于，所述制备方法包括以下步骤：
    刻蚀：将负载有第一金属单原子的导电基底置于过氧化物水溶液中刻蚀，得到刻蚀后的第一金属单原子材料；
    金属双原子材料的制备：将上述得到的刻蚀后的第一金属单原子材料负载第二金属单原子，即得到金属双原子材料。
  6. 根据权利要求5所述的金属双原子材料的制备方法，其特征在于，所述刻蚀的具体方法如下：
    步骤A、将醇和水混合成溶液，将负载有第一金属单原子的导电基底置于混合溶液中，超声；
    步骤B、将步骤A得到的混合溶液搅拌同时均匀滴加过氧化物水溶液，得混合均匀的反应液；
    步骤C、将步骤B得到的反应液转移到高压反应釜中，置于烘箱中，设定反应温度为100～200℃，反应3～10小时；反应结束后，对高压反应釜中反应结束得到的固体材料进行过滤和洗涤，并真空冷冻干燥，得到刻蚀后的第一金属单原子材料。
  7. 根据权利要求5所述的金属双原子材料的制备方法，其特征在于，所述 金属双原子材料的制备具体方法如下：
    将刻蚀后的第一金属单原子材料溶解于醇和水的混合溶液中，超声直至得到分散均匀的浑浊液，并称取适量的第二金属的前驱体加入浑浊液，混合均匀，固液分离，并将得到的固体材料进行真空冷冻干燥；
    将冷冻干燥后得到的固体材料置于瓷舟内，在惰性气体的保护下碳化，之后自然降温至室温，最终得到金属双原子材料。
  8. 根据权利要求5所述的金属双原子材料的制备方法，其特征在于，所述过氧化物水溶液中的过氧化物选自过氧化氢、过氧二硫酸盐、过硫酸盐、过氧乙酸盐、过氧磷酸盐或过氧碳酸盐中的一种或几种。
  9. 根据权利要求5所述的金属双原子材料的制备方法，其特征在于，所述导电基底为氮碳基底时，所述负载有第一金属单原子的导电基底的制备方法如下：
    (a)将甲酰胺作为溶剂溶解第一金属盐和锌盐，超声以确保两种盐类充分溶解于甲酰胺中，得到水热反应母液A，第一金属盐和锌盐的摩尔比为1:4～1:20；
    (b)将上述水热反应母液A倒入密闭反应釜中，在160℃～220℃和自生压力下进行水热反应，结束后，将密封反应釜自然冷却至室温，固液分离，洗涤固体，得到无甲酰胺残留的固体材料B，并将固体材料B烘干得到固体材料C；
    (c)将固体材料C研磨后置于瓷舟内，在惰性气体保护下升温，再在800℃-1100℃下，恒温2-6小时，待反应结束后自然冷却至室温，制得所述负载有第一金属单原子的导电基底。
  10. 根据权利要求5所述的金属双原子材料的制备方法，其特征在于，所述导电基底为硫氮碳基底时，所述负载有第一金属单原子的导电基底的制备方法如下：
    (a)将甲酰胺作为溶剂溶解第一金属盐、锌盐和硫源，超声以确保两种盐类充分溶解于甲酰胺中，得到水热反应母液A，第一金属盐和锌盐的摩尔比为1:4～1:20，硫源的摩尔量和第一金属盐保持一致；
    (b)将上述水热反应母液A倒入密闭反应釜中，在160℃～220℃和自生压力下进行水热反应，结束后，将密封反应釜自然冷却至室温，固液分离，洗涤固体，得到无甲酰胺残留的固体材料B，并将固体材料B烘干得到固体材料C；
    (c)将固体材料C研磨后置于瓷舟内，在惰性气体保护下升温，再在 600℃～1100℃下恒温1～4小时，待反应结束后自然冷却至室温，制得所述负载有第一金属单原子的导电基底。
  11. 根据权利要求9所述的金属双原子材料的制备方法，其特征在于，所述第一金属盐中的第一金属选自：钴、铁、锌、镍、锰、铂、钌、铱、金、银中的一种或几种。
  12. 根据权利要求7所述的金属双原子材料的制备方法，其特征在于，所述第二金属的前驱体为第二金属盐，第二金属选自：钴、铁、锌、镍、锰、铂、钌、铱、金、银一种或几种。
  13. 根据权利要求1～4任一项所述的金属双原子材料用于催化氧还原反应的用途。
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CN112938966A (zh) * 2021-02-08 2021-06-11 北京化工大学 一种磷、氮共掺杂的铁单原子碳材料及其制备方法和用途
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