Accordion-type carbon-supported single-atom-cluster catalysts, methods of making and use

Abstract

The present application relates to oxygen precipitation and oxygen reduction electrocatalyst technical field, especially an accordion type carbon supported single atom-cluster catalyst and preparation method and application. The present application first synthesizes a kind of accordion type coordination polymer containing zinc and iron series metal (such as iron, cobalt, nickel), then it is etched using potassium ferricyanide or potassium cobalticyanide;Finally, pyrolysis is carried out under nitrogen atmosphere, forming an accordion type carbon supported single atom-cluster catalyst. The new catalyst has a unique accordion type layered structure, higher specific surface area, more active sites, and the main skeleton nitrogen-doped carbon of the catalyst has good conductivity, which can accelerate the mass transfer and charge transfer process of electrocatalytic reaction. The present application belongs to a new type of bifunctional catalyst, which can catalyze oxygen reduction reaction and drive oxygen precipitation reaction, meet the needs of rechargeable zinc-air battery, and show potential application prospect to replace commercialized noble metal catalyst.

Description

Technical Field

[0001] This invention relates to the field of catalyst preparation technology, and in particular to an accordion-type carbon matrix supported iron-based metal single-atom cluster catalyst, its preparation method, and its application. Background Technology

[0002] Due to growing environmental concerns and the explosive growth in global energy demand, the development of sustainable energy materials and green nanotechnology for constructing fuel cells, metal-air batteries, and water electrolysis systems has attracted global attention. In particular, zinc-air batteries (ZABs) have proven to be a promising technology capable of meeting the needs of future energy conversion devices due to their widely recognized advantages, including theoretical energy density that meets requirements, low cost, environmental friendliness, and reliable safety. As key reactions in rechargeable ZAB devices, the oxygen reduction reaction (ORR) during discharge and the oxygen evolution reaction (OER) during charging are crucial to the entire electrocatalytic process. However, the slow kinetics of ORR and OER lead to unfavorable polarization losses, making efficient catalysts to accelerate these reactions a central issue. While noble metal materials, such as Pt-based catalysts and RuO2, have long been considered the benchmarks for catalyzing ORR and OER respectively, their single catalytic activity, high cost, and poor cycling stability limit their further commercial application. Therefore, the development of inexpensive, efficient, and stable transition metal-based bifunctional oxygen catalytic materials is particularly important.

[0003] In recent years, iron-based metal single-atom catalysts have attracted much attention due to their extremely high atom utilization, excellent catalytic activity, and low cost, and have been widely used in oxygen evolution and oxygen reduction reactions. Recent studies have found that the reversible oxygen catalytic activity of single-atom catalysts can be further improved by utilizing the interactions between metal atoms and supports, heteroatoms, and even other metal centers. However, the influence of multinuclear sites (e.g., atomic clusters) on isolated single-atom sites is often overlooked. Therefore, a deeper understanding of catalytic activity and catalytic mechanisms is needed. Furthermore, the lack of effective and universal synthetic strategies makes it difficult to study the interactions between different active sites. Therefore, developing a universal synthetic method for constructing iron-based metal single-atom-cluster hybrid materials for efficient oxygen evolution and oxygen reduction reactions remains a major challenge. Summary of the Invention

[0004] One objective of this invention is to provide a method for preparing an accordion-type carbon matrix supported iron-based metal single-atom-cluster catalyst. The catalyst prepared by this method has a unique accordion-like layered structure with a higher specific surface area, thus accommodating more active sites and exhibiting excellent conductivity and electrocatalytic performance.

[0005] To achieve the above objectives, the present invention employs the following technical solution: a method for preparing an accordion-type carbon-supported single-atom-cluster catalyst, comprising the following steps:

[0006] Preparation of S1, Zn-A based coordination polymers

[0007] Dissolve 2-methylimidazole in deionized water to a concentration of 4.93-493 mg / mL, and stir until homogeneous to form solution 1;

[0008] Dissolve acetic acid tetrahydrate A and zinc acetate dihydrate in deionized water and stir until homogeneous to form solution 2. The concentration of zinc acetate dihydrate in solution 2 is 1.10-110 mg / mL and the concentration of acetic acid tetrahydrate A is 0.0625-6.25 mg / mL.

[0009] Solution 1 and solution 2 were mixed at a volume ratio of 1:1 while stirring for 12 hours. The precipitate was collected by centrifugation, washed with deionized water and anhydrous ethanol, and then dried to obtain the Zn-A-based coordination polymer.

[0010] Preparation of S2, Zn-AB-based coordination polymers

[0011] The Zn-Ni-based coordination polymer was dispersed in deionized water at a concentration of 0.67-67 mg / mL to obtain solution 3;

[0012] Potassium cyanide (K3[B(CN)6]) was dissolved in deionized water to a concentration of 0.375-37.50 mg / mL, yielding solution 4;

[0013] Solution 3 and solution 4 were thoroughly mixed and stirred at a volume ratio of 15:8, then allowed to stand. The precipitate was collected by centrifugation, washed with deionized water and anhydrous ethanol, and dried to obtain the Zn-AB-based coordination polymer.

[0014] S3, Accordion-shaped carbon matrix supported on B 单原子-团簇 -A 单原子 Preparation of electrocatalysts

[0015] The Zn-AB-based coordination polymer was loaded into a ceramic boat and placed in a tube furnace. It was calcined at 500-700℃ for 1-2 hours under a nitrogen atmosphere with a heating rate of 1-10℃ / min, then heated to 920-1000℃ and calcined for 1-5 hours. Finally, it was cooled to room temperature under a nitrogen atmosphere to obtain an accordion-shaped carbon matrix-supported B... 单原子-团簇 -A 单原子 Electrocatalyst;

[0016] The elements A and B are not the same and are both one of Fe, Co, and Ni.

[0017] Further improvements to the preparation method of accordion-type carbon-supported single-atom-cluster catalysts:

[0018] Preferably, when solutions 1 and 2 are mixed in a 1:1 volume ratio in step S1, the mass ratio of 2-methylimidazole in solution 1 to acetic acid tetrahydrate A and zinc acetate dihydrate in solution 2 is 493:110:6.25.

[0019] Preferably, the concentration of 2-methylimidazole in solution 1 is 49.3 mg / mL; the concentration of acetic acid tetrahydrate A in solution 2 is 0.625 mg / mL, and the concentration of zinc acetate dihydrate is 11.0 mg / mL.

[0020] Preferably, when solutions 3 and 4 are fully mixed in a volume ratio of 15:8 in step S2, the mass ratio of the Zn-Ni-based coordination polymer in solution 3 to the potassium cyanide in solution 4 is 67:20.

[0021] Preferably, the concentration of Zn-A group coordination polymer in solution 3 is 6.7 mg / mL, and the concentration of potassium cyanide B, i.e., K3[B(CN)6], in solution 4 is 3.75 mg / mL.

[0022] The second objective of this invention is to provide an accordion-type carbon-supported single-atom cluster catalyst prepared by the above-mentioned method.

[0023] The third objective of this invention is to provide an application of the above-mentioned accordion-type carbon-supported single-atom-cluster catalyst in zinc-air batteries.

[0024] The advantages of this invention compared to the prior art are as follows:

[0025] 1) This invention provides a method for preparing an accordion-shaped carbon matrix-supported iron-based metal single-atom cluster catalyst. First, an accordion-shaped MOF material, i.e., an accordion-shaped coordination polymer containing zinc and iron-based metals (iron, cobalt, nickel), is prepared through a simple liquid-phase synthesis route. After etching with potassium ferricyanide or potassium cobalt cyanide, ferricyanide or cobalt cyanide ions react with the metal ions in the MOF material to generate corresponding Prussian blue analogs, thereby introducing the iron or cobalt source into the precursor and preparing a class of accordion-shaped coordination polymers containing zinc and iron-based metals (iron, cobalt, nickel). After high-temperature pyrolysis, zinc ions are reduced by the ligands and become vapor, escaping from the derived carbon matrix (calcination temperature is higher than the boiling point of zinc). Iron-based metals are also reduced to their metallic state by the ligands during pyrolysis, but because their boiling points are much higher than the calcination temperature, they do not become vapor and escape from the material system, but are instead captured by the nitrogen-doped carbon matrix. Furthermore, the spatial physical barrier of zinc ions, the coating of the carbon matrix, and the coordination of nitrogen prevented further growth and aggregation of the iron-based metals, thus preparing nitrogen-doped carbon-supported iron-based metal single-atom-cluster hybrid materials. Throughout the process, the accordion-like morphology was perfectly maintained.

[0026] 2) The synthesis steps of this invention are simple and easy to operate, with a high synthesis yield and higher catalytic activity compared to commercial catalysts. This catalyst is low in cost and readily available, and as a cathode material for zinc-air batteries, it exhibits excellent cycle stability and good power density.

[0027] 3) From the perspective of catalyst structure, the catalyst of the present invention has a unique accordion-like structure. This structure has a higher specific surface area, thus it can accommodate more active sites and exhibit excellent oxygen reduction and oxygen evolution performance. At the same time, it accelerates the charge transfer process in the electrocatalytic process. The main framework of the catalyst is nitrogen-doped carbon, which has good conductivity, thus it can improve the mass transfer and charge transfer process of the electrocatalytic reaction.

[0028] From a catalytic perspective, unlike commercial Pt / C catalysts which are only suitable for non-rechargeable zinc-air batteries (because the discharge process requires good oxygen evolution performance), the catalyst of this invention is a bifunctional catalyst that can catalyze both the oxygen reduction reaction and drive the oxygen evolution reaction, meeting the needs of rechargeable zinc-air batteries. Moreover, the performance of the catalyst is better than that of commercial oxygen reduction catalysts (Pt / C) and oxygen evolution catalysts (RuO2), showing potential to replace commercial precious metal catalysts.

[0029] The accordion-type carbon matrix supported Fe of the present invention 单原子-团簇 -Ni 单原子 In the oxygen reduction reaction (ORR) driven by the electrocatalyst, the ORR half-wave potential is 0.93V (higher voltage results in better performance), and the limiting current is 5.75mA / cm.2 On the oxygen evolution curve, the catalyst of this invention achieves a current density of 10 mA / cm². 2 The required voltage is 1.592V (the lower the voltage, the better the performance), and the corresponding overpotential is as low as 362mV; the performance of both OER and ORR is excellent.

[0030] The accordion-type carbon matrix supported Fe of the present invention 单原子-团簇 -Co 单原子 The electrocatalyst exhibits an ORR potential of 0.901 V and a limiting current of 5.575 mA / cm² in the oxygen reduction reaction driven by the oxygen catalyst. 2 For the oxygen evolution reaction, at a current density of 10 mA / cm² 2 The overpotential corresponding to the oxygen evolution reaction is 385mV, demonstrating excellent electrocatalytic oxygen evolution activity.

[0031] The accordion-type carbon matrix supported Co of the present invention 单原子-团簇 -Ni 单原子 The electrocatalyst exhibits an ORR potential of 0.891 V and a limiting current of 5.375 mA / cm² in the oxygen reduction reaction driven by the oxygen catalyst. 2 For the oxygen evolution reaction, at a current density of 10 mA / cm² 2 The overpotential corresponding to the oxygen evolution reaction is 399mV, demonstrating excellent electrocatalytic oxygen evolution activity.

[0032] 4) The synergistic effect between different active metals can lower the energy barrier of intermediate absorption / desorption, enhance charge transfer, and achieve stable and superior ORR and OER activities. The multilayer structure endows the sample with a good electrochemical active area and charge transfer behavior, accelerating related electrochemical reactions. The highly graphitized carbon matrix not only improves the conductivity of the catalyst but also effectively protects the active components. The performance of bifunctional electrocatalysis depends not only on the contribution of each component but also on their synergistic effect. Attached Figure Description

[0033] Figure 1 Fe supported on an accordion-shaped carbon matrix 单原子-团簇 -Ni 单原子 Flowchart of electrocatalyst preparation;

[0034] Figure 2 Fe supported on an accordion-shaped carbon matrix 单原子-团簇 -Ni 单原子 X-ray powder diffraction pattern of electrocatalyst and X-ray powder diffraction standard card;

[0035] Figure 3 Fe supported on an accordion-shaped carbon matrix 单原子-团簇 -Ni 单原子 Raman spectra of electrocatalysts;

[0036] Figure 4 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Ni signal in X-ray photoelectron spectroscopy of electrocatalyst;

[0037] Figure 5 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Fe signal in X-ray photoelectron spectroscopy of electrocatalyst;

[0038] Figure 6 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 The C signal in the X-ray photoelectron spectroscopy of electrocatalysts;

[0039] Figure 7 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 The N signal in the X-ray photoelectron spectroscopy of electrocatalysts;

[0040] Figure 8 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Ni signal fitting analysis diagram of synchrotron radiation EXAFS for electrocatalysts;

[0041] Figure 9 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Fe signal fitting analysis diagram of synchrotron radiation EXAFS for electrocatalysts;

[0042] Figure 10 Fe supported on an accordion-shaped carbon matrix 单原子-团簇 -Ni 单原子 Transmission electron microscope image of the electrocatalyst;

[0043] Figure 11 Fe supported on an accordion-shaped carbon matrix 单原子-团簇 -Ni 单原子 Aberration-corrected transmission electron microscope image of the electrocatalyst;

[0044] Figure 12 Fe supported on an accordion-shaped carbon matrix 单原子-团簇 -Ni 单原子 Oxygen evolution reaction curves of electrocatalyst and noble metal RuO2;

[0045] Figure 13 Fe supported on an accordion-shaped carbon matrix 单原子-团簇 -Ni 单原子 Oxygen reduction reaction curves of electrocatalyst and noble metal Pt / C;

[0046] Figure 14 Fe supported on an accordion-shaped carbon matrix 单原子-团簇 -Ni 单原子 Charge-discharge polarization curves of the electrocatalyst, and charge-discharge polarization curves of the Pt / C and RuO2 mixed catalyst;

[0047] Figure 15 Fe supported on an accordion-shaped carbon matrix 单原子-团簇 -Ni 单原子 Charge-discharge curves of the electrocatalyst and the charge-discharge curves of the Pt / C and RuO2 mixed catalyst. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0049] Example 1

[0050] This embodiment provides an accordion-shaped carbon matrix supported on Fe. 单原子-团簇 -Ni 单原子 The preparation method of the electrocatalyst specifically includes the following steps:

[0051] Preparation of S1, Zn-Ni based coordination polymers

[0052] Dissolve 1.97 g of 2-methylimidazole in 40 mL of deionized water to obtain a concentration of 0.0493 g / mL, and stir until homogeneous to form solution 1; dissolve 0.438 g of zinc acetate dihydrate and 0.025 g of nickel acetate tetrahydrate in 40 mL of deionized water to obtain a concentration of 0.011 g / mL of zinc acetate dihydrate and a concentration of 0.000625 g / mL of nickel acetate tetrahydrate, and stir until homogeneous to form solution 2;

[0053] Solution 1 and solution 2 were mixed at a volume ratio of 1:1 under stirring and stirred at room temperature for 12 hours. The resulting precipitate was collected by centrifuge, washed with deionized water and anhydrous ethanol, and then dried to obtain the Zn-Ni-based coordination polymer.

[0054] Preparation of S2, Zn-Ni-Fe based coordination polymers

[0055] 100 mg of Zn-Ni-based coordination polymer was dispersed in 15 mL of deionized water to obtain solution 3, with a concentration of 0.0067 g / mL. 30 mg of potassium ferricyanide K3[Fe(CN)6] was dissolved in 8 mL of deionized water to obtain solution 4, with a concentration of 0.00375 g / mL. Solutions 3 and 4 were thoroughly mixed at a volume ratio of 15:8 and allowed to stand. The precipitate was collected by centrifugation, washed with deionized water and anhydrous ethanol, and then dried to obtain the Zn-Ni-Fe-based coordination polymer.

[0056] S3, Accordion-shaped carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Preparation of electrocatalysts

[0057] Zn-Ni-Fe based coordination polymers were loaded into ceramic boats and then placed in a tube furnace. The furnace was calcined at 600°C for 1 hour at a heating rate of 3°C / min under a nitrogen atmosphere, followed by calcination at 920°C for 2 hours. The furnace was then cooled to room temperature under a nitrogen atmosphere to obtain accordion-shaped carbon matrix-supported Fe. 单原子-团簇 -Ni 单原子 Electrocatalyst.

[0058] The above-synthesized accordion-shaped carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 The process of electrocatalysts is as follows Figure 1 As shown.

[0059] Figure 2 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 The X-ray diffraction pattern of the electrocatalyst and the corresponding XRD standard card C (00-041-1487). The standard card shows only a carbon signal, which proves the presence of a carbon matrix.

[0060] Figure 3 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Raman spectrum of an electrocatalyst. From Figure 7 It can be clearly seen in the image at 1350cm -1 and 1590cm -1 There are two distinct peaks at this point, corresponding to the D and G bands of the carbon material, respectively. The ratio of the peak intensity of the D peak to the peak intensity of the G peak (I...) D / I G The ratio (Ig) is an important parameter characterizing the degree of graphitization of carbon materials; a smaller ratio indicates a higher degree of graphitization. Calculations show that the synthesized catalyst has an Ig... D / I G The value is approximately 0.88, which indicates that the catalyst contains carbon materials and has a high degree of graphitization.

[0061] Figure 4 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 The Ni signal in the X-ray photoelectron spectroscopy of the electrocatalyst; 854.2 eV and 872.0 eV correspond to Ni-N bonds, 855.8 eV and 873.6 eV correspond to oxidized Ni, and 861.3 eV and 878.6 eV correspond to satellite peaks, proving the presence of ionic Ni in the catalyst.

[0062] Figure 5 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 The Fe signal in the X-ray photoelectron spectroscopy of the electrocatalyst shows that 707.1 eV and 720.5 eV correspond to metallic Fe, 709.2 eV and 723.1 eV correspond to Fe-N bonds, 711.6 eV, 714.8 eV, 724.5 eV and 728.3 eV correspond to oxidized Fe, and 717.8 eV and 729.6 eV correspond to satellite peaks, proving the presence of metallic Fe in the catalyst and demonstrating the presence of atomic clusters and single atoms in the catalyst.

[0063] Figure 6 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 The C signal in the X-ray photoelectron spectrum of the electrocatalyst, located at 284.4, 285.3, and 286.5 eV, corresponds to CC, C=C, and CN, respectively, proving the presence of a carbon matrix.

[0064] Figure 7 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 The N signal in the X-ray photoelectron spectrum of the electrocatalyst; located at 398.1, 399.0, 400.1, 400.9, and 402.8 eV, corresponding to pyridine N, metal-N, pyrrole N, graphitic N, and oxide-N. Pyridine and graphitic N species can effectively enhance the conductivity of the electrocatalyst, thereby accelerating the electrocatalytic process involved.

[0065] Figure 8 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Synchrotron radiation EXAFS analysis of the electrocatalyst shows the presence of Fe-N and Fe-Fe, confirming the existence of Fe single atoms and Fe clusters.

[0066] Figure 9 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子Synchrotron radiation EXAFS analysis of the Ni signal. The presence of Ni-N is evident, confirming the existence of Ni single atoms.

[0067] Figure 10 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Transmission electron microscope image of an electrocatalyst. (By...) Figure 7 It can be seen that the product morphology shows an accordion-like layered structure, which is beneficial to the mass and charge transfer process in the electrocatalytic process.

[0068] Figure 11 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 The aberration-corrected transmission electron microscope image of the electrocatalyst shows the bright spots in the small circles as Ni and Fe single atoms, and the large circles as Fe clusters.

[0069] Figure 12 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 The oxygen evolution reaction curves of the electrocatalyst and the oxygen evolution reaction curve of the commercial noble metal RuO2 are shown in the figure. (The solid line represents the synthesized accordion-shaped carbon matrix supported Fe.) 单原子-团簇 -Ni 单原子 Electrocatalyst; (dashed line: synthesis of commercially available noble metal RuO2); calculations show that accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Electrocatalyst, with a current density reaching 10 mA / cm² 2 The required overpotential is 362mV, which is lower than that of the noble metal RuO2.

[0070] Figure 13 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Oxygen reduction reaction curves of electrocatalysts with noble metal Pt / C (solid line shows the synthesized accordion-shaped carbon matrix supported Fe). 单原子-团簇 -Ni 单原子 Electrocatalyst; dashed line represents the synthesis of commercially viable noble metals Pt / C, from... Figure 10 It can be seen that the half-wave potential of the obtained electrocatalyst is 0.93V, and the limiting current is 5.750mA / cm. 2 The half-wave potential of commercially available precious metal Pt / C is 0.835V, and the limiting current is 5.31mA / cm². 2 Therefore, the accordion-shaped carbon matrix supports Fe 单原子-团簇 -Ni 单原子 Electrocatalysts outperform the noble metal Pt / C.

[0071] Figure 14It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Charge-discharge polarization diagram of the electrocatalyst in a reversible zinc-air battery. (Solid lines represent the synthesized accordion-shaped carbon matrix supported Fe.) 单原子-团簇 -Ni 单原子 Electrocatalyst; dashed line: commercially available noble metal Pt / C+RuO2). At a current density of 50 mA / cm² 2 At that time, the ΔE of the electrocatalyst was 0.840V, while the ΔE of the noble metal Pt / C+RuO2 was 1.21V. The results show that our electrocatalyst performs better than the noble metal Pt / C+RuO2.

[0072] Figure 15 It is an accordion-type carbon matrix supported on Fe 单原子-团簇 -Ni 单原子 Charge-discharge curves of the electrocatalyst in a reversible zinc-air battery. (Solid lines represent the synthesized accordion-shaped carbon matrix supported Fe.) 单原子-团簇 -Ni 单原子 Electrocatalyst; dashed line: commercially available precious metal Pt / C + RuO2. As shown in the figure, the charge-discharge time of this battery can reach 180 hours, and the ΔE is 0.18V at 2h; 0.22V at 70h; and 0.58V at 180h, which is far superior to the RuO2 and Pt / C mixed catalyst.

[0073] Example 2

[0074] This embodiment provides an accordion-shaped carbon matrix supported on Fe. 单原子-团簇 -Co 单原子 The preparation method of the electrocatalyst specifically includes the following steps:

[0075] Preparation of S1, Zn-Co based coordination polymers

[0076] Dissolve 1.97 g of 2-methylimidazole in 40 mL of deionized water to obtain a concentration of 0.0493 g / mL, and stir until homogeneous to form solution 1; dissolve 0.438 g of zinc acetate dihydrate and 0.025 g of cobalt acetate tetrahydrate in 40 mL of deionized water to obtain a concentration of 0.011 g / mL of zinc acetate dihydrate and a concentration of 0.000625 g / mL of cobalt acetate tetrahydrate, and stir until homogeneous to form solution 2;

[0077] Solution 1 and solution 2 were mixed at a volume ratio of 1:1 under stirring and stirred at room temperature for 12 hours. The resulting precipitate was collected by centrifuge, washed with deionized water and anhydrous ethanol, and then dried to obtain the Zn-Co-based coordination polymer.

[0078] Preparation of S2, Zn-Co-Fe based coordination polymers

[0079] The Zn-Co-based coordination polymer was dispersed in deionized water at a concentration of 0.0067 g / mL to obtain solution 3; potassium ferricyanide K3[Fe(CN)6] was dissolved in deionized water at a concentration of 0.00375 g / mL to obtain solution 4; solutions 3 and 4 were thoroughly mixed at a volume ratio of 15:8, allowed to stand, and the precipitate was collected by centrifugation. The precipitate was then washed with deionized water and anhydrous ethanol and dried to obtain the Zn-Co-Fe-based coordination polymer.

[0080] S3, Accordion-shaped carbon matrix supported on Fe 单原子-团簇 -Co 单原子 Preparation of electrocatalysts

[0081] Zn-Co-Fe based coordination polymers were loaded into ceramic boats and then placed in a tube furnace. The furnace was calcined at 600°C for 1 hour at a heating rate of 3°C / min under a nitrogen atmosphere, followed by calcination at 920°C for 2 hours. The furnace was then cooled to room temperature under a nitrogen atmosphere to obtain an accordion-shaped carbon matrix-supported Fe. 单原子-团簇 -Co 单原子 Electrocatalyst.

[0082] Testing revealed that the accordion-shaped carbon matrix loaded with Fe prepared in this embodiment... 单原子-团簇 -Co 单原子 Electrocatalyst at a current density of 10 mA / cm 2 At this time, the overpotential corresponding to the oxygen evolution reaction is 385 mV, exhibiting excellent electrocatalytic oxygen evolution activity. For the oxygen reduction reaction, the half-wave potential is 0.901 V, and the limiting current is 5.375 mA / cm². 2 When this catalyst is used as the air electrode, the assembled rechargeable zinc-air battery operates at a current density of 50 mA / cm². 2 The ΔE value is 0.857V, and the charge / discharge time of the battery can reach 90 hours. The ΔE value is 0.34V after 2 hours, 0.47V after 70 hours, and 0.62V after 90 hours, which is far superior to the RuO2 and Pt / C mixed catalyst.

[0083] Example 3

[0084] An accordion-shaped carbon matrix supported on Co 单原子-团簇 -Ni 单原子 The preparation method of the electrocatalyst includes the following steps:

[0085] Preparation of S1, Zn-Ni based coordination polymers

[0086] Dissolve 1.97 g of 2-methylimidazole in 40 mL of deionized water to obtain a concentration of 0.0493 g / mL, and stir until homogeneous to form solution 1; dissolve 0.438 g of zinc acetate dihydrate and 0.025 g of nickel acetate tetrahydrate in 40 mL of deionized water to obtain a concentration of 0.011 g / mL of zinc acetate dihydrate and a concentration of 0.000625 g / mL of nickel acetate tetrahydrate, and stir until homogeneous to form solution 2;

[0087] Solution 1 and solution 2 were mixed at a volume ratio of 1:1 under stirring and stirred at room temperature for 12 hours. The resulting precipitate was collected by centrifuge, washed with deionized water and anhydrous ethanol, and then dried to obtain the Zn-Ni-based coordination polymer.

[0088] Preparation of S2, Zn-Ni-Co based coordination polymers

[0089] A Zn-Ni-based coordination polymer was dispersed in deionized water at a concentration of 0.0067 g / mL to obtain solution 3; potassium ferricyanide K3[Co(CN)6] was dissolved in deionized water at a concentration of 0.00375 g / mL to obtain solution 4; solutions 3 and 4 were thoroughly mixed and stirred at a volume ratio of 15:8, allowed to stand, and the precipitate was collected by centrifugation. The precipitate was then washed with deionized water and anhydrous ethanol and dried to obtain the Zn-Ni-Co-based coordination polymer.

[0090] S3, Accordion-shaped carbon matrix supported on Co 单原子-团簇 -Ni 单原子 Preparation of electrocatalysts

[0091] Zn-Ni-Co based coordination polymers were loaded into ceramic boats and then placed in a tube furnace. The furnace was calcined at 600°C for 1 hour at a heating rate of 3°C / min under a nitrogen atmosphere, followed by calcination at 920°C for 2 hours. The furnace was then cooled to room temperature under a nitrogen atmosphere to obtain an accordion-shaped carbon matrix-supported Co. 单原子-团簇 -Ni 单原子 Electrocatalyst.

[0092] Testing revealed that the accordion-shaped carbon matrix-supported Co prepared in this embodiment... 单原子-团簇 -Ni 单原子 Electrocatalyst at a current density of 10 mA / cm 2 The overpotential for the oxygen evolution reaction is 399 mV, while the half-wave potential for the oxygen reduction reaction is 0.890 V, and the limiting current is 5.210 mA / cm². 2 When this catalyst is used as the air electrode, the assembled rechargeable zinc-air battery operates at a current density of 50 mA / cm². 2The ΔE value is 0.875V, and the charge / discharge time of the battery can reach 80 hours. The ΔE value is 0.40V after 2 hours, 0.51V after 70 hours, and 0.67V after 80 hours, which is far superior to the RuO2 and Pt / C mixed catalyst.

[0093] Those skilled in the art should understand that the above descriptions are merely several specific embodiments of the present invention, and not all embodiments. It should be noted that many modifications and improvements can be made by those skilled in the art, and all modifications or improvements not exceeding the scope of the claims should be considered within the protection scope of the present invention.

Claims

1. A method for preparing an accordion-type carbon-supported single-atom-cluster catalyst, characterized in that, Includes the following steps: Preparation of S1, Zn-A based coordination polymers Dissolve 2-methylimidazole in deionized water to a concentration of 4.93-493 mg / mL, and stir until homogeneous to form solution 1; Dissolve acetic acid tetrahydrate A and zinc acetate dihydrate in deionized water and stir until homogeneous to form solution 2. The concentration of zinc acetate dihydrate in solution 2 is 1.10-110 mg / mL and the concentration of acetic acid tetrahydrate A is 0.0625-6.25 mg / mL. Solution 1 and solution 2 were mixed in a 1:1 volume ratio under stirring. The mass ratio of 2-methylimidazole in solution 1 to acetic acid tetrahydrate and zinc acetate dihydrate in solution 2 was 493:110:6.

25. The mixture was stirred for 12 hours, and the precipitate was collected by centrifugation. The precipitate was washed with deionized water and anhydrous ethanol and then dried to obtain the Zn-A-based coordination polymer. Preparation of S2, Zn-AB-based coordination polymers The Zn-A-based coordination polymer was dispersed in deionized water at a concentration of 0.67-67 mg / mL to obtain solution 3; Potassium cyanide (K3[B(CN)6]) was dissolved in deionized water to a concentration of 0.375-37.50 mg / mL, yielding solution 4; Solution 3 and solution 4 were thoroughly mixed and stirred at a volume ratio of 15:

8. During mixing, the mass ratio of Zn-A-based coordination polymer in solution 3 to potassium cyanide B in solution 4 was 67:

20. The mixture was then allowed to stand, centrifuged to collect the precipitate, and then washed with deionized water and anhydrous ethanol and dried to obtain Zn-AB-based coordination polymer. S3, Accordion-shaped carbon matrix supported on B 单原子-团簇 -A 单原子 Preparation of electrocatalysts The Zn-AB-based coordination polymer was loaded into a ceramic boat and placed in a tube furnace. It was calcined at 500-700°C for 1-2 hours under a nitrogen atmosphere with a heating rate of 1-10°C / min, then heated to 920-1000°C and calcined for 1-5 hours. Finally, it was cooled to room temperature under a nitrogen flow to obtain an accordion-shaped carbon matrix-supported B. 单原子-团簇 -A 单原子 Electrocatalysts are used in zinc-air batteries to catalyze oxygen reduction and oxygen evolution reactions. A and B are different and both are one of Fe, Co, or Ni.

2. The method for preparing the accordion-type carbon-supported single-atom-cluster catalyst according to claim 1, characterized in that, The concentration of 2-methylimidazole in solution 1 was 49.3 mg / mL; the concentration of acetic acid tetrahydrate A in solution 2 was 0.625 mg / mL, and the concentration of zinc acetate dihydrate was 11.0 mg / mL.

3. The method for preparing the accordion-type carbon-supported single-atom-cluster catalyst according to claim 1, characterized in that, The concentration of Zn-A group coordination polymer in solution 3 was 6.7 mg / mL, and the concentration of potassium cyanide B, K3[B(CN)6] in solution 4 was 3.75 mg / mL.

4. An accordion-type carbon-supported single-atom cluster catalyst prepared by the preparation method according to any one of claims 1-3.

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