Supported PtFe dual-atom catalyst and its preparation method and application

Abstract

The present invention relates to a preparation method of a supported PtFe dual-atom catalyst. By mixing FeNC with ammonium chloride and pyrolyzing them, and then using the ALD method to uniformly deposit Pt single atoms on the surface of FeNC / AC, a supported dual-atom catalyst PtFeNC / AC is prepared. Due to its high-exposure surface, gradient porous structure, and stable metal loading sites, FeNC / AC provides an ideal support for the successful construction of dual-atom catalysts. Based on its self-saturation limitation and selective deposition characteristics, the ALD technique can control the deposition of Pt single atoms at the atomic scale, which is beneficial to the precise and controllable synthesis of PtFe dual-atom catalysts. By regulating the coordination environment of Pt atomic active sites, the multifunctional synergistic catalysis of low-Pt dual-atom catalysts in fuel cells is realized. Under the condition of greatly reducing the Pt loading amount, the catalytic efficiency of the catalyst for hydrogen oxidation at the anode of fuel cells can be significantly improved, while effectively reducing the production and preparation costs.

Description

Technical Field

[0001] The present invention relates to the technical field of fuel cell electrocatalysis, and specifically to a preparation method of a supported PtFe dual-atom catalyst, and the application of the supported PtFe dual-atom catalyst in the anodic hydrogen oxidation of a fuel cell. Background Art

[0002] As an energy conversion device that directly converts hydrogen energy into electrical energy, the proton exchange membrane fuel cell (PEMFC) has the advantages of being clean, efficient, low-carbon and environmentally friendly compared with thermal power generation and heat engine power generation, and is a major strategic direction for the world's energy transformation and power transformation. The electrode catalyst is used to lower the reaction activation energy barrier and increase the reaction rate, and is regarded as the key core material of PEMFC. The most effective catalyst for PEMFC is mainly platinum-carbon (Pt / C). However, the high cost, limited reserves of the noble metal Pt, and the problems of aggregation inactivation and poor stability under the battery operating conditions seriously restrict the commercialization process of PEMFC. Therefore, the development of new catalysts with high activity, low Pt loading, and high stability is of great significance for breaking through the main bottlenecks of PEMFC.

[0003] The prior art discloses a hybrid electrocatalyst composed of atomically dispersed Pt single atoms, Fe single atoms, and Pt-Fe alloy nanoparticles. The Pt acetylacetonate is dispersed in a solvent, a nitrogen source and Fe-doped ZIF-8 are added to prepare a suspension, and after drying, ball milling is carried out to obtain Fe-ZIF-8 distributed with Pt and the nitrogen source, and finally Zn is removed by high-temperature treatment to prepare a Pt-Fe-NC catalyst, wherein the Pt loading is 1.7%. However, the Pt deposition rate is slow during its preparation process, and it is impossible to synthesize precisely controlled PtFe nanoparticles and clusters, and it is impossible to precisely control a stable PtFe dual-atom catalyst. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of slow Pt deposition rate and inability to precisely control stable PtFe dual atoms in the preparation process of the PtFe bimetallic catalyst in the prior art, and thus provide a supported PtFe dual-atom catalyst for hydrogen energy fuel cell applications and its preparation method. After mixing and pyrolyzing FeNC with ammonium chloride, the low-loading Pt single atoms are uniformly deposited on the surface of FeNC / AC by the Atomic Layer Deposition (ALD) method to prepare a supported low-Pt dual-atom catalyst PtFeNC / AC, which can control the deposition of Pt single atoms at the atomic scale, is beneficial to the precise and controllable synthesis of PtFe dual-atom catalysts, can significantly improve the catalytic efficiency of the catalyst in the anodic hydrogen oxidation of the fuel cell while greatly reducing the Pt loading, and effectively reduces the production and preparation costs.

[0005] To solve the above technical problems, the present invention is achieved through the following technical solutions.

[0006] The first aspect of the present invention provides a method for preparing a supported PtFe dual-atom catalyst, comprising the following steps:

[0007] (1) Dissolve zinc salt and iron salt in an organic solvent and mix evenly, add 2-methylimidazole solution, and stir and react together at room temperature; then centrifuge, wash, and dry to obtain Fe-ZIF-8;

[0008] (2) High-temperature carbonize Fe-ZIF-8 under an inert gas atmosphere to obtain Fe-NC containing Fe single atoms;

[0009] (3) Mix Fe-NC with NH4Cl and perform high-temperature pyrolysis under an inert gas atmosphere to obtain a mesoporous Fe-NC / AC support;

[0010] (4) Deposit Pt single atoms on the surface of the Fe-NC / AC support using ALD to obtain the product.

[0011] Preferably, the zinc salt in step (1) is selected from one or more of zinc chloride, zinc bromide, zinc nitrate, zinc sulfate, zinc acetate, and their hydrates.

[0012] Preferably, the iron salt in step (1) is selected from one or more of ferric chloride, ferric bromide, ferric nitrate, ferric sulfate, and ferric acetate.

[0013] Preferably, the mass ratio of the zinc salt to the iron salt in step (1) is 10 - 30:1; more preferably, the mass ratio of the zinc salt to the iron salt is 20 - 25:1.

[0014] Preferably, the mass ratio of the zinc salt to 2-methylimidazole in the 2-methylimidazole solution in step (1) is 0.5 - 1:1; more preferably, the mass ratio of the zinc salt to 2-methylimidazole in the 2-methylimidazole solution is 0.7 - 0.9:1.

[0015] Preferably, the organic solvent in step (1) is selected from one or more of methanol, ethanol, isopropanol, acetone, chloroform, and tetrahydrofuran.

[0016] Preferably, the solvent of the 2-methylimidazole solution in step (1) is selected from one or more of methanol, ethanol, isopropanol, acetone, chloroform, and tetrahydrofuran.

[0017] Preferably, the stirring reaction time in step (1) is 12 - 48 h; more preferably, the stirring reaction time is 18 - 30 h.

[0018] Preferably, the drying in step (1) is vacuum drying.

[0019] Preferably, the temperature of the high-temperature carbonization in step (2) is 800 - 1200 °C, and the time is 1 - 5 h; more preferably, the temperature of the high-temperature carbonization is 900 - 1100 °C, and the time is 1.5 - 3 h.

[0020] Preferably, the inert gas in step (2) is selected from one or more of nitrogen, helium, and argon.

[0021] Preferably, the mass ratio of Fe-NC to NH4Cl in step (3) is 1:2 - 5; more preferably, the mass ratio of Fe-NC to NH4Cl is 1:2.5 - 4.

[0022] Preferably, the temperature of the high-temperature pyrolysis in step (3) is 500 - 900 °C, and the time is 20 - 120 min; more preferably, the temperature of the high-temperature pyrolysis is 600 - 800 °C, and the time is 40 - 80 min.

[0023] Preferably, the inert gas in step (3) is selected from one or more of nitrogen, helium, and argon.

[0024] Preferably, the specific parameters of ALD in step (4) are: performing 2 - 8 cycles (2c - 8c) of ALD deposition of Pt; most preferably, the specific parameters of ALD are: performing 2 cycles (2c) of ALD deposition of Pt.

[0025] The second aspect of the present invention provides a supported PtFe dual-atom catalyst prepared according to the above preparation method.

[0026] Preferably, in the supported PtFe dual-atom catalyst, Pt and Fe are dispersed in the carrier in the structure of a dual-atom pair.

[0027] Preferably, the average distance between PtFe dual atoms in the supported PtFe dual-atom catalyst is 0.33 - 0.35 nm.

[0028] The third aspect of the present invention provides the application of the supported PtFe dual-atom catalyst prepared according to the above preparation method in the anode of a fuel cell.

[0029] Preferably, the application is specifically the anodic hydrogen oxidation reaction and / or the cathodic oxygen reduction reaction.

[0030] The present invention has the following technical effects compared with the prior art:

[0031] Through a large amount of research, the present invention prepares a supported low-Pt dual-atom catalyst 2cPtFeNC / AC by pyrolyzing the mixture of FeNC and ammonium chloride and then uniformly depositing low-loading Pt single atoms on the surface of FeNC / AC by the atomic layer deposition method of a specific process. The Pt loading is 0.4 wt%, and the Fe loading is 0.37 wt%. The Pt loading is significantly lower than the prior art level. Due to the high-exposure surface, gradient porous structure, and stable metal loading sites, FeNC / AC provides an ideal support for the successful construction of dual-atom catalysts. Based on the characteristics of self-saturation limitation and selective deposition, the ALD technology can control the deposition of Pt single atoms at the atomic scale, which is beneficial to the precise and controllable synthesis of PtFe dual-atom catalysts. By regulating the coordination environment of Pt atomic active sites, the multifunctional cooperative catalysis of the low-Pt dual-atom catalyst in the fuel cell is realized. When the Pt loading is greatly reduced, the catalytic efficiency of the catalyst for hydrogen oxidation at the anode of the fuel cell can be significantly improved. In order to obtain a dual-atom morphology catalyst, strict restrictions are imposed on the ALD deposition parameters. The present invention finds that when the number of ALD deposition cycles is too large, a mixed morphology of single atoms and atomic clusters will be formed, seriously affecting the catalytic performance of the catalyst. When performing 2 cycles (2c) of ALD deposition of Pt, a catalyst with a uniform structure and optimal performance in the form of PtFe dual atoms can be obtained. The 2cPtFeNC / AC dual-atom catalyst of the present invention exhibits excellent specific mass activity (10.5 Amg Pt -1 ) in the hydrogen oxidation reaction at the anode of the fuel cell, which is 48.5 times the specific mass activity of the commercial nanoparticle Pt / C (0.2A mg Pt -1 ) catalyst. At the same time, the significant reduction of the Pt loading can effectively reduce the production cost. The present invention helps to realize the precise construction of low-Pt dual-atom catalysts, providing an excellent catalyst system with high activity, high stability, and low cost for hydrogen energy fuel cells. Description of the Drawings

[0032] Figure 1 It is a low-magnification transmission electron micrograph of the supported low-Pt dual-atom catalyst 2cPtFeNC / AC obtained in Example 1.

[0033] Figure 2 It is a high-magnification transmission electron micrograph of the supported low-Pt dual-atom catalyst 2cPtFeNC / AC obtained in Example 1.

[0034] Figure 3 It is a spherical aberration corrected transmission electron microscope AC-HAADF-STEM image of the supported low-Pt dual-atom catalyst 2cPtFeNC / AC obtained in Example 1.

[0035] Figure 4Pt-Fe dual-atom distance distribution diagram of the supported low-Pt dual-atom catalyst 2cPtFeNC / AC obtained in Example 1.

[0036] Figure 5 EDS distribution diagrams of C, N, Fe, and Pt elements in the supported low-Pt dual-atom catalyst 2cPtFeNC / AC obtained in Example 1.

[0037] Figure 6 Morphology diagram of the ALD 10cPtFeNC / AC catalyst obtained in Comparative Example 1.

[0038] Figure 7 Pt NP Morphology diagram of the FeNC / AC catalyst obtained in Comparative Example 2.

[0039] Figure 8 Morphology diagram of the ALD 2cPtNC / AC single-atom catalyst obtained in Comparative Example 3.

[0040] Figure 9 Current-voltage performance curve diagram of different catalysts in the hydrogen oxidation reaction.

[0041] Figure 10 Schematic diagram of the specific mass activity results of different catalysts in the hydrogen oxidation reaction.

[0042] Figure 11 Schematic diagram of the performance polarization curve results of the H2-O2 fuel cell. Detailed implementation manners

[0043] To make the objectives, technical solutions and effects of the present invention clearer and more definite, the present invention will be further described in detail below with reference to the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] Example 1

[0045] A supported low-Pt dual-atom catalyst, and its preparation method specifically includes the following steps:

[0046] (1) 6.74 g of Zn(NO3)2·6H2O and 0.326 g of Fe(NO3)3·9H2O were stirred and dissolved in 1000 mL of methanol, and 1000 mL of 2-methylimidazole methanol solution (containing 7.88 g of 2-methylimidazole) was added, and the mixture was stirred at room temperature for 24 h; then centrifuged, washed, and vacuum dried to obtain Fe-ZIF-8.

[0047] (2) Fe-ZIF-8 was heated to 1000 °C in a nitrogen atmosphere for 2 h of high-temperature carbonization to obtain Fe-NC containing Fe single atoms.

[0048] (3) Mix Fe-NC and NH4Cl evenly at a mass ratio of 1:3, heat to 700 °C in a nitrogen atmosphere for 1 h of high-temperature pyrolysis to obtain a Fe-NC / AC support with a mesoporous structure.

[0049] (4) Using Fe-NC / AC as the base material, under vacuum conditions, perform 2 cycles of Pt source pulses by ALD to deposit Pt single atoms on the surface of the support, namely obtaining the 2cPtFeNC / AC dual-atom material.

[0050] Example 2

[0051] A supported low-Pt dual-atom catalyst, and its preparation method specifically includes the following steps:

[0052] (1) Stir and dissolve 6.74 g of Zn(NO3)2·6H2O and 0.326 g of Fe(NO3)3·9H2O in 1000 mL of methanol, add 1000 mL of 2-methylimidazole methanol solution (containing 7.88 g of 2-methylimidazole), and stir and react together at room temperature for 24 h; then centrifuge, wash, and vacuum dry to obtain Fe-ZIF-8.

[0053] (2) Heat Fe-ZIF-8 to 900 °C in a nitrogen atmosphere for 3 h of high-temperature carbonization to obtain Fe-NC containing Fe single atoms.

[0054] (3) Mix Fe-NC and NH4Cl evenly at a mass ratio of 1:3, heat to 600 °C in a nitrogen atmosphere for 80 min of high-temperature pyrolysis to obtain a Fe-NC / AC support with a mesoporous structure.

[0055] (4) Using Fe-NC / AC as the base material, under vacuum conditions, perform 2 cycles of Pt source pulses by ALD to deposit Pt single atoms on the surface of the support, namely obtaining the 2cPtFeNC / AC dual-atom material.

[0056] Example 3

[0057] A supported low-Pt dual-atom catalyst, and its preparation method specifically includes the following steps:

[0058] (1) Stir and dissolve 6.74 g of Zn(NO3)2·6H2O and 0.326 g of Fe(NO3)3·9H2O in 1000 mL of methanol, add 1000 mL of 2-methylimidazole methanol solution (containing 7.88 g of 2-methylimidazole), and stir and react together at room temperature for 24 h; then centrifuge, wash, and vacuum dry to obtain Fe-ZIF-8.

[0059] (2) Heat Fe-ZIF-8 to 1100 °C under a nitrogen atmosphere for 1.5 h of high-temperature carbonization to obtain Fe-NC containing single Fe atoms.

[0060] (3) Uniformly mix Fe-NC and NH4Cl in a mass ratio of 1:3, heat to 800 °C under a nitrogen atmosphere for 40 min of high-temperature pyrolysis to obtain a mesoporous-structured Fe-NC / AC support.

[0061] (4) Using Fe-NC / AC as the base material, under vacuum conditions, perform 2 cycles of Pt source pulses for ALD to deposit single Pt atoms on the surface of the support, thus obtaining the 2cPtFeNC / AC dual-atom material.

[0062] Comparative Example 1

[0063] A supported low-Pt catalyst, and its preparation method specifically includes the following steps:

[0064] (1) Stir and dissolve 6.74 g of Zn(NO3)2·6H2O and 0.326 g of Fe(NO3)3·9H2O in 1000 mL of methanol, add 1000 mL of 2-methylimidazole methanol solution (containing 7.88 g of 2-methylimidazole), and stir and react together at room temperature for 24 h; then centrifuge, wash, and vacuum dry to obtain Fe-ZIF-8.

[0065] (2) Heat Fe-ZIF-8 to 1000 °C under a nitrogen atmosphere for 2 h of high-temperature carbonization to obtain Fe-NC containing single Fe atoms.

[0066] (3) Uniformly mix Fe-NC and NH4Cl in a mass ratio of 1:3, heat to 700 °C under a nitrogen atmosphere for 1 h of high-temperature pyrolysis to obtain a mesoporous-structured Fe-NC / AC support.

[0067] (4) Using Fe-NC / AC as the base material, under vacuum conditions, perform 10 cycles of Pt source pulses for ALD to obtain a mixture of single Pt atoms and atomic clusters on the surface of the support, thus obtaining the 10cPtFeNC / AC cluster catalyst material.

[0068] Comparative Example 2

[0069] A supported nanoparticle Pt NP FeNC / AC catalyst, and its preparation method specifically includes the following steps:

[0070] (1) 6.74 g of Zn(NO3)2·6H2O and 0.326 g of Fe(NO3)3·9H2O were stirred and dissolved in 1000 mL of methanol. 1000 mL of 2-methylimidazole methanol solution (containing 7.88 g of 2-methylimidazole) was added, and the mixture was stirred at room temperature for 24 h. Subsequently, it was centrifuged, washed, and dried under vacuum to obtain Fe-ZIF-8.

[0071] (2) Fe-ZIF-8 was heated to 1000 °C in a nitrogen atmosphere for high-temperature carbonization for 2 h to obtain Fe-NC containing single Fe atoms.

[0072] (3) Fe-NC and NH4Cl were uniformly mixed at a mass ratio of 1:3 and heated to 700 °C in a nitrogen atmosphere for high-temperature pyrolysis for 1 h to obtain a mesoporous Fe-NC / AC support.

[0073] (4) 20 mg of Fe-NC / AC was weighed and ultrasonically dispersed in ethylene glycol (EG). An appropriate amount of H2Pt / Cl6·6H2O was added to the dispersion of Fe-NC / AC. Then, NaOH was added to the mixed solution to adjust the pH to 11, and the mixed solution was heated to boiling and then cooled to room temperature. Finally, it was washed 5 times with ultrapure water to obtain nanometer particles Pt NP FeNC / AC catalyst.

[0074] Comparative Example 3

[0075] A supported low-Pt atom catalyst, and its preparation method specifically includes the following steps:

[0076] (1) 6.74 g of Zn(NO3)2·6H2O was stirred and dissolved in 1000 mL of methanol. 1000 mL of 2-methylimidazole methanol solution (containing 7.88 g of 2-methylimidazole) was added, and the mixture was stirred at room temperature for 24 h. Subsequently, it was centrifuged, washed, and dried under vacuum to obtain ZIF-8.

[0077] (2) ZIF-8 was heated to 1000 °C in a nitrogen atmosphere for high-temperature carbonization for 2 h to obtain metal-free NC.

[0078] (3) NC and NH4Cl were uniformly mixed at a mass ratio of 1:3 and heated to 700 °C in a nitrogen atmosphere for high-temperature pyrolysis for 1 h to obtain a mesoporous NC / AC support;

[0079] (4) Using NC / AC as the base material, under vacuum conditions, 2 cycles of Pt source pulses were performed for ALD to deposit Pt on the surface of the support, and the 2cPtNC / AC catalyst material was obtained.

[0080] Verification Example 1

[0081] First, the morphology of the supported low-Pt dual-atom catalyst 2cPtFeNC / AC prepared in Example 1 of the present invention was detected. Among them Figure 1 is a low-magnification transmission electron microscopy image, Figure 2 is a high-magnification transmission electron microscopy image, Figure 3 is a spherical aberration corrected transmission electron microscopy ACHAADFSTEM image, Figure 4 is a statistical graph of the Pt-Fe dual-atom distance, Figure 5 is the energy spectrum distribution diagram of C, N, Fe, and Pt elements in the dual-atom catalyst. The results show that Pt and Fe representing metal sites appear in pairs in the form of dual atoms, the average distance of PtFe dual atoms is 0.33 - 0.35 nm, and each element is evenly dispersed on the carrier. The above results indicate that the supported 2cPtFeNC / AC dual-atom catalyst was successfully prepared by the ALD technology regulated with specific parameters in this example, and Pt and Fe are evenly dispersed in the carrier in the form of dual-atom pairs, where the Pt loading is about 0.4 wt%, and the Fe loading is about 0.37 wt%.

[0082] Secondly, the morphology of the catalysts prepared in Comparative Examples 1 - 3 of the present invention was detected. As Figure 2 shown in the transmission electron microscopy and spherical aberration electron microscopy images, the morphology diagram of the ALD 10cPtFeNC / AC catalyst prepared in Comparative Example 1 is as Figure 6 shown, where Figure 6 (a) is a low-magnification transmission electron microscopy image, Figure 6 (b) is a high-magnification transmission electron microscopy image, Figure 6 (c) is a spherical aberration corrected transmission electron microscopy image. The results show that there are no obvious Pt nanoparticles on the surface of the ALD 10cPtFeNC / AC catalyst, and Pt is distributed on the surface of the carrier in the form of single atoms and atomic clusters; inductively coupled plasma emission spectroscopy shows that the Pt loading in the 10cPtFeNC / AC catalyst is 1.0 wt%, and the Fe loading is 0.37 wt%. In Comparative Example 2, a Pt NP FeNC / AC catalyst containing only Pt particles dispersed on the surface of the FeNC / AC carrier was prepared by a chemically assisted microwave reduction method, and its morphology diagram is as Figure 7 shown, where Figure 7 (a) is a low-magnification transmission electron microscopy image, Figure 7 (b) is a high-magnification transmission electron microscopy image. The results show that in the Pt NP FeNC / AC catalyst, Pt is dispersed on the surface of the carrier in the form of nanoparticles with a particle size of 3 - 5 nm, and inductively coupled plasma emission spectroscopy shows that the Pt loading in Pt NP FeNC / AC is 2.5 wt%. In addition, in Comparative Example 3, a 2cPtNC / AC catalyst was prepared by depositing 2 cycles of Pt on the NC substrate by ALD, and its morphology diagram is asFigure 8 as shown, where Figure 8 (a) is a low-magnification transmission electron microscopy image, Figure 8 (b) is a high-magnification transmission electron microscopy image. The results show that there is an uneven dispersion of Pt atoms and clusters in ALD 2c PtNC / AC. Inductively coupled plasma optical emission spectrometry shows that the Pt loading is 0.9 wt%, indicating that the Fe single atoms in the support material play an important role in anchoring Pt atoms.

[0083] Subsequently, the catalysts prepared in Example 1, Comparative Examples 1-3, and commercial Pt / C catalyst were respectively used for fuel cell anodic hydrogen oxidation performance tests. The test conditions were as follows: Electrochemical workstation: Bio Logic electrochemical workstation from France; Counter electrode: Pt sheet electrode; Reference electrode: Reversible hydrogen electrode; Electrolyte: 0.1 M HClO4 solution; The hydrogen oxidation performance in the three-electrode and single-cell test results are as Figures 9 - 11 shown. The results show that by constructing PtFe dual-atom active sites, the ALD 2c PtFeNC / AC supported dual-atom catalyst prepared in Example 1 of the present invention has a limiting diffusion current density of 2.5 mA cm at 0.05 V in a challenging acidic electrolyte -2 , compared with the ALD deposited 10c PtFeNC / AC catalyst (2.1 mA cm) in Comparative Example 1 -2 ), the ALD 2c Pt-NC / AC single-atom catalyst (1.9 mA cm) in Comparative Example 3 -2 ) and the nanoparticle Pt NP FeNC / AC catalyst (1.8 mA cm) in Comparative Example 2 -2 ), its catalytic performance has obvious advantages (as Figure 9 shown). More importantly, the ALD 2c PtFe-N-C dual-atom catalyst prepared in Example 1 of the present invention exhibits extremely high specific mass activity. At a potential of 0.05 V, its specific mass activity is 10.6 mA·mg Pt -1 , much higher than that of the ALD 10c PtFeNC / AC (4.8 mA·mg Pt -1 ) catalyst in Comparative Example 1, the Pt NP FeNC / AC (4.7 mA·mg Pt -1 ) catalyst in Comparative Example 2, the 2cPt-NC / AC single-atom (2.5 mA·mg Pt -1 ) catalyst in Comparative Example 3, and commercial Pt / C (0.2 mA·mg Pt -1) The catalyst is 48.5 times as active as the commercial nanoparticle Pt / C catalyst (see Figure 10 ). In the application of the anode of a hydrogen-oxygen fuel cell, the ALD 2cPtFeNC / AC supported dual-atom catalyst prepared in Example 1 of the present invention, at an extremely low Pt loading of 0.02 mg Pt cm -2 , can exhibit better battery discharge performance than the commercial nanoparticle Pt / C catalyst (0.4 mg Pt cm -2 ) (see Figure 11 ).

[0084] The above specific embodiments part specifically introduces the analysis method involved in the present invention. It should be noted that the above introduction is only to help those skilled in the art better understand the method and idea of the present invention, rather than a limitation on the relevant content. Without departing from the principle of the present invention, those skilled in the art can also make appropriate adjustments or modifications to the present invention, and the above adjustments and modifications should also fall within the protection scope of the present invention.

Claims

1. A preparation method of a supported PtFe dual-atom catalyst, characterized in that, It includes the following steps: (1) Dissolve zinc salt and iron salt in an organic solvent and mix evenly. Add 2-methylimidazole solution and stir the reaction together at room temperature. Then, centrifuge, wash, and dry to obtain Fe-ZIF-8; (2) High-temperature carbonize Fe-ZIF-8 under an inert gas atmosphere to obtain Fe-NC containing single Fe atoms; (3) Mix Fe-NC with NH4Cl and perform high-temperature pyrolysis under an inert gas atmosphere to obtain a mesoporous-structured Fe-NC / AC support; (4) Deposit single Pt atoms on the surface of the Fe-NC / AC support using ALD to obtain the dual-atom catalyst PtFeNC / AC; the specific parameters of the ALD are: perform 2 cycles of ALD deposition of Pt.

2. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of the zinc salt to the iron salt is 10-30:

1.

3. The preparation method according to claim 1, characterized in that, In step (1), the mass ratio of the zinc salt to 2-methylimidazole in the 2-methylimidazole solution is 0.5-1:

1.

4. The preparation method according to claim 1, characterized in that, In step (2), the temperature of the high-temperature carbonization is 800-1200 °C, and the time is 1-5 h.

5. The preparation method according to claim 1, characterized in that, In step (3), the mass ratio of Fe-NC to NH4Cl is 1:2-5.

6. The preparation method according to claim 1, characterized in that, In step (3), the temperature of the high-temperature pyrolysis is 500-900 °C, and the time is 20-120 min.

7. A supported PtFe dual-atom catalyst prepared by the preparation method according to any one of claims 1-6.

8. The supported PtFe dual-atom catalyst according to claim 7, wherein In the supported PtFe dual-atom catalyst, Pt and Fe are dispersed in the support in the structure of a dual-atom pair.

9. The supported PtFe dual-atom catalyst according to claim 7, wherein In the supported PtFe dual-atom catalyst, the average distance between the PtFe dual atoms is 0.33-0.35 nm.

Images