Preparation method of dendritic MnOOH-MnO2 (at) Pt monatomic catalyst and application of dendritic MnOOH-MnO2 (at) Pt monatomic catalyst in aluminum air battery

Abstract

The invention relates to a preparation method of a dendritic MnOOH-MnO2 (at) Pt monatomic catalyst and application of the dendritic MnOOH-MnO2 (at) Pt monatomic catalyst in an aluminum air battery. The MnO2 nanoparticle loaded Pt monatomic catalyst is accurately synthesized on the MnOOH nanowire through a strategy of'Pt monatomic induction + in-situ symbiosis'. Compared with the MnO2 (at) Pt catalyst with the nanowire-shaped structure, the MnOOH-MnO2 (at) Pt catalyst with the dendritic structure has a local electric field enhancement effect, so that reactants are enriched, and the activity of the oxygen reduction reaction is improved. An electrochemical test result shows that the specific capacity of the aluminum air battery taking MnOOH-MnO2 (at) Pt as the cathode is 2381 mAh g <-1 >, which is far better than that of most cathode catalysts reported at present, and the aluminum air battery can stably run for 650 hours at 50 mA cm <-2 >. By designing the catalyst with a unique dendritic structure, effective regulation and control of a local microenvironment are realized, and a new thought is provided for design and synthesis of the aluminum air battery cathode catalyst.

Description

Technical Field

[0001] This invention belongs to the field of inorganic nanomaterials technology, specifically relating to a method for preparing a dendritic MnOOH-MnO2@Pt single-atom catalyst and its application. Background Technology

[0002] Aluminum-air batteries possess advantages such as being non-toxic and harmless, having high specific energy, low cost, and good safety, and are hailed as a "green energy source for the 21st century," showing great promise in backup power, emergency power, and new energy vehicles. As a key half-reaction in aluminum-air batteries, the slow kinetics of the oxygen reduction reaction (ORR) hinder its commercial application, typically requiring highly efficient catalysts to reduce the reaction overpotential and improve energy conversion efficiency. Currently, platinum (Pt)-based catalysts are considered the benchmark catalysts for ORR due to their excellent catalytic activity. However, the high cost and scarcity of Pt severely limit its large-scale commercial application. Therefore, developing low-cost, highly active, and highly stable low-platinum-based catalysts has become a research hotspot.

[0003] Currently, low-platinum-based catalysts exhibit significant advantages in aluminum-air batteries, primarily due to their highly efficient oxygen reduction reaction (ORR) catalytic activity and excellent stability. Platinum can significantly reduce the overpotential of ORR, accelerating reaction kinetics and thus improving the battery's power density and voltage efficiency. Simultaneously, its strong corrosion resistance in alkaline electrolytes ensures the long-term stability of low-platinum-based catalysts. Furthermore, low-platinum-based catalysts can promote ORR and suppress side reactions, reducing energy loss. A related study (Nature Communications. 2024, 15, 6650) designed CuO with tunable valence states. x / Cu hybrid nanoparticles, acting as a valence electron pool, enable in-situ regulation of the 5d electron occupancy state of Pt during the reaction, thereby effectively enhancing the intrinsic electrocatalytic ORR activity of Pt-based catalysts. However, this study did not compare with more stable supports such as transition metal oxides, which may provide stronger Pt anchoring capabilities through oxygen vacancies. Patent (CN119252945A) discloses a method for preparing a dense platinum monolayer catalyst for fuel cell cathodes, involving single-atom-layer Pt substitution. This method is environmentally friendly, has simple reaction conditions, and can be applied to fuel cells, etc.

[0004] Although some progress has been made in low-platinum-based catalysts, the challenge of precisely controlling the spatial position of platinum single atoms in the support remains, making it difficult to achieve efficient utilization of active sites and resulting in the specific capacity of aluminum-air batteries being far lower than the theoretical value. Therefore, it is still imperative to explore new insights into low-platinum-based ORR catalysts. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a dendritic MnOOH-MnO2@Pt single-atom catalyst. This invention proposes a "Pt single-atom induction + in-situ co-production" strategy to precisely synthesize Pt single-atom catalysts supported on MnO2 nanoparticles on MnOOH nanowires, efficiently regulating the local reaction microenvironment around the catalytic site and significantly improving the performance of aluminum-air batteries.

[0006] This invention also provides an application of a dendritic MnOOH-MnO2@Pt single-atom catalyst.

[0007] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing a dendritic MnOOH-MnO2@Pt single-atom catalyst, comprising the following steps: (1) Disperse the amino acids evenly in water to form solution 1; (2) Add potassium permanganate to solution 1 and mix well to obtain solution 2; (3) Stir the solution 2 obtained in step (2), and after hydrothermal reaction, wash and dry to obtain MnOOH; (4) Platinum salt and MnOOH obtained in step (3) are sequentially dispersed in a mixed solution of water and ethylene glycol. After hydrothermal reaction, the mixture is washed and dried to obtain MnOOH-MnO2@Pt catalyst. Alternatively, the MnOOH obtained in step (3) can be calcined in air at 400±50 °C for 3-5 h to obtain nanowire-shaped MnO2. Then, platinum salt and MnO2 are dispersed in a mixed solution of water and ethylene glycol. After hydrothermal reaction, the mixture is washed and dried to obtain a nanowire-shaped MnO2@Pt single-atom catalyst.

[0008] Specifically, the amino acids in step (1) include, but are not limited to, any one or more of cysteine, serine, threonine, etc. The molar ratio of the amino acids to potassium permanganate can be 1:1-6.

[0009] Furthermore, the concentration of amino acids in step (1) is 0.0025-0.0075 mol / L. The concentration of potassium permanganate in step (2) is 0.0075-0.045 mol / L.

[0010] Specifically, the hydrothermal reaction temperature in step (3) is 140-200 ℃, and the reaction time is 8-24 h.

[0011] Specifically, in step (4), the volume ratio of water to ethylene glycol is between 3:1 and 1:3.

[0012] Specifically, in step (4), the hydrothermal reaction temperature is 80-120 ℃ and the reaction time is 4-8 h.

[0013] Furthermore, in step (4), the platinum salt includes, but is not limited to, any one or more of potassium chloroplatinate, chloroplatinic acid, sodium chloroplatinate, etc.; the platinum loading can be 0.5-1.5 wt% of the catalyst mass.

[0014] In this invention, the catalyst MnO2@Pt has an overall nanowire structure with Pt single atoms distributed on the MnO2 nanowires; the catalyst MnOOH-MnO2@Pt has an overall dendritic structure with Pt single atoms precisely distributed on the MnO2 nanoparticles.

[0015] This invention provides a dendritic MnOOH-MnO2@Pt single-atom catalyst prepared by the above preparation method.

[0016] This invention also provides the application of the above-mentioned dendritic MnOOH-MnO2@Pt single-atom catalyst in the preparation of aluminum-air battery cathodes. The dendritic MnOOH-MnO2@Pt single-atom catalyst prepared by the process of this invention exhibits excellent specific capacity and stability in the cathode of aluminum-air batteries.

[0017] Compared with the prior art, the present invention has the following beneficial effects: 1) This invention can controllably prepare MnOOH-MnO2@Pt single-atom catalysts through the strategy of "Pt single-atom induction + in-situ symbiosis". The overall structure is a dendritic structure, and Pt single atoms are precisely distributed on MnO2 nanoparticles. 2) Compared to the nanowire structure MnO2@Pt, the local electric field strength of the dendritic structure MnOOH-MnO2@Pt is increased by 3.25 times, which significantly improves the enrichment concentration of reactants; 3) An aluminum-air battery assembled using the prepared catalyst as the cathode has a specific capacity of 2381 mAh g. -1 It outperforms most reported catalysts and is at 50 mA cm⁻¹ -2 It can operate stably for 650 hours. This invention develops a precise synthesis technique for single-atom catalysts, providing a new approach to improving the performance of aluminum-air batteries by enhancing the local microenvironment. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 X-ray diffraction (XRD) patterns of the dendritic MnOOH-MnO2@Pt single-atom catalyst prepared in Example 1 and the nanowire-structured MnO2@Pt single-atom catalyst prepared in Example 2; Figure 2 Transmission electron microscopy (TEM, a), aberration-corrected transmission electron microscopy (AC-TEM, b), and elemental mapping (EDS, c) images of the dendritic MnOOH-MnO2@Pt single-atom catalyst prepared in Example 1 are shown. Figure 3 The images show transmission electron microscopy (TEM, a), aberration-corrected transmission electron microscopy (AC-TEM, b), and elemental mapping (EDS, c) images of the nanowire-structured MnO2@Pt single-atom catalyst prepared in Example 2. Figure 4 Figure 1 shows the local electric field distribution of the dendritic MnOOH-MnO2@Pt single-atom catalyst prepared in Example 1 and the nanowire MnO2@Pt single-atom catalyst prepared in Example 2; where a and b are schematic diagrams of the local electric field distribution of Examples 2 and 1, respectively, and c shows the specific electric field strength values ​​from A to B for the two structures. Figure 5 The dendritic MnOOH-MnO2@Pt single-atom catalyst prepared in Example 1 and the nanowire-structured MnO2@Pt single-atom catalyst prepared in Example 2 were compared at 6 mol·L⁻¹ -1 Polarization curves and corresponding power density plots in KOH solution; Figure 6 The dendritic MnOOH-MnO2@Pt single-atom catalyst prepared in Example 1 was tested at 50 mA·cm⁻¹. -2 The discharge curve below; Figure 7 This is a comparison of the specific capacity of the dendritic MnOOH-MnO2@Pt single-atom catalyst prepared in Example 1 as an electrocatalyst in aluminum-air batteries assembled with other electrocatalysts reported in the literature. Detailed Implementation

[0020] To better understand the content of this invention, the technical solution of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0021] Unless otherwise specified, the experimental methods used in the following experimental examples are conventional methods; the materials and reagents used are commercially available unless otherwise specified.

[0022] Example 1 (1) Prepare a cysteine ​​solution with a concentration of 0.005 mol / L using 80 mL of water as solvent, and stir magnetically to obtain mixed solution A; wherein the stirring time is 10 min; (2) Under stirring conditions, potassium permanganate with a concentration of 0.02 mol / L was added to the above cysteine ​​solution and magnetically stirred to obtain a microemulsion; wherein the stirring time was 1 h. (3) The microemulsion was subjected to a hydrothermal reaction at a heating rate of 3 °C / min, a reaction temperature of 180 °C, and a reaction time of 12 h. The solution obtained after the reaction was filtered, washed, and dried at 60 °C for 12 h to obtain MnOOH. (4) Sodium chloroplatinate was added to MnOOH (the amount of sodium chloroplatinate added was based on the platinum loading being 1.0% of the catalyst mass), and the mixture was dispersed in 5 mL of ethylene glycol and 10 mL of deionized water for hydrothermal reaction. The heating rate was 3 °C / min, the reaction temperature was 100 °C, and the reaction time was 285 min. After washing and drying, the dendritic MnOOH-MnO2@Pt single-atom catalyst was finally obtained.

[0023] Example 2 (1) Prepare a cysteine ​​solution with a concentration of 0.005 mol / L using 80 mL of water as solvent, and stir magnetically to obtain mixed solution A; wherein the stirring time is 10 min; (2) Under stirring conditions, potassium permanganate with a concentration of 0.02 mol / L was added to the above cysteine ​​solution and magnetically stirred to obtain a microemulsion; wherein the stirring time was 1 h. (3) The microemulsion was subjected to a hydrothermal reaction at a heating rate of 3 °C / min, a reaction temperature of 180 °C, and a reaction time of 12 h. The solution obtained after the reaction was filtered, washed, and dried at 60 °C for 12 h to obtain MnOOH. (4) MnOOH was thermally oxidized in air atmosphere. The heating rate of the thermal oxidation process was 5 °C / min, the oxidation temperature was 400 °C, and the oxidation time was 4 h to obtain MnO2 nanowires. (5) Sodium chloroplatinate was added to MnO2 (the amount of sodium chloroplatinate added was based on the platinum loading being 1.0% of the catalyst mass), and the mixture was dispersed in 5 mL of ethylene glycol and 10 mL of deionized water for hydrothermal reaction. The heating rate was 3 °C / min, the reaction temperature was 100 °C, and the reaction time was 285 min. After washing and drying, the nanowire structure MnO2@Pt single-atom catalyst was finally obtained.

[0024] Example 3 (1) Prepare a cysteine ​​solution with a concentration of 0.005 mol / L using 80 mL of water as solvent, and stir magnetically to obtain mixed solution A; wherein the stirring time is 10 min; (2) Under stirring conditions, potassium permanganate with a concentration of 0.02 mol / L was added to the above cysteine ​​solution and magnetically stirred to obtain a microemulsion; wherein the stirring time was 1 h. (3) The microemulsion was subjected to a hydrothermal reaction at a heating rate of 3 °C / min, a reaction temperature of 180 °C, and a reaction time of 12 h. The solution obtained after the reaction was filtered, washed, and dried at 60 °C for 12 h to obtain MnOOH. (4) Sodium chloroplatinate was added to MnOOH (the amount of sodium chloroplatinate added was based on the platinum loading being 0.8% of the catalyst mass), and the mixture was dispersed in 10 mL of ethylene glycol and 10 mL of deionized water for hydrothermal reaction. The heating rate was 3 °C / min, the reaction temperature was 100 °C, and the reaction time was 6 h. After washing and drying, the dendritic MnOOH-MnO2@Pt single-atom catalyst was finally obtained.

[0025] Example 4 (1) Prepare a cysteine ​​solution with a concentration of 0.005 mol / L using 80 mL of water as solvent, and stir magnetically to obtain mixed solution A; wherein the stirring time is 10 min; (2) Under stirring conditions, potassium permanganate with a concentration of 0.02 mol / L was added to the above cysteine ​​solution and magnetically stirred to obtain a microemulsion; wherein the stirring time was 1 h. (3) The microemulsion was subjected to a hydrothermal reaction at a heating rate of 3 °C / min, a reaction temperature of 180 °C, and a reaction time of 12 h. The solution obtained after the reaction was filtered, washed, and dried at 60 °C for 12 h to obtain MnOOH. (4) MnOOH was thermally oxidized in air atmosphere. The heating rate of the thermal oxidation process was 5 °C / min, the oxidation temperature was 400 °C, and the oxidation time was 4 h to obtain MnO2 nanowires. (5) Sodium chloroplatinate was added to MnO2 (the amount of sodium chloroplatinate added was based on the platinum loading being 0.8% of the catalyst mass), and the mixture was dispersed in 10 mL of ethylene glycol and 10 mL of deionized water for hydrothermal reaction. The heating rate was 3 °C / min, the reaction temperature was 100 °C, and the reaction time was 6 h. After washing and drying, the nanowire structure MnO2@Pt single-atom catalyst was finally obtained.

[0026] Example 5 (1) Prepare a cysteine ​​solution with a concentration of 0.005 mol / L using 80 mL of water as solvent, and stir magnetically to obtain mixed solution A; wherein the stirring time is 10 min; (2) Under stirring conditions, potassium permanganate with a concentration of 0.03 mol / L was added to the above cysteine ​​solution and magnetically stirred to obtain a microemulsion; wherein the stirring time was 1 h. (3) The microemulsion was subjected to a hydrothermal reaction at a heating rate of 3 °C / min, a reaction temperature of 200 °C, and a reaction time of 12 h. The solution obtained after the reaction was filtered, washed, and dried at 60 °C for 12 h to obtain MnOOH. (4) Sodium chloroplatinate was added to MnOOH (the amount of sodium chloroplatinate added was based on the platinum loading being 1.2% of the catalyst mass), and the mixture was dispersed in 5 mL of ethylene glycol and 10 mL of deionized water for hydrothermal reaction. The heating rate was 3 °C / min, the reaction temperature was 100 °C, and the reaction time was 6 h. After washing and drying, the dendritic MnOOH-MnO2@Pt single-atom catalyst was finally obtained.

[0027] Example 6 (1) Prepare a cysteine ​​solution with a concentration of 0.005 mol / L using 80 mL of water as solvent, and stir magnetically to obtain mixed solution A; wherein the stirring time is 10 min; (2) Under stirring conditions, potassium permanganate with a concentration of 0.03 mol / L was added to the above cysteine ​​solution and magnetically stirred to obtain a microemulsion; wherein the stirring time was 1 h. (3) The microemulsion was subjected to a hydrothermal reaction at a heating rate of 3 °C / min, a reaction temperature of 200 °C, and a reaction time of 12 h. The solution obtained after the reaction was filtered, washed, and dried at 60 °C for 12 h to obtain MnOOH. (4) MnOOH was thermally oxidized in air atmosphere. The heating rate of the thermal oxidation process was 5 °C / min, the oxidation temperature was 400 °C, and the oxidation time was 4 h to obtain MnO2 nanowires. (5) Sodium chloroplatinate was added to MnO2 (the amount of sodium chloroplatinate added was based on the platinum loading being 1.2% of the catalyst mass), and the mixture was dispersed in 5 mL of ethylene glycol and 10 mL of deionized water for hydrothermal reaction. The heating rate was 3 °C / min, the reaction temperature was 100 °C, and the reaction time was 6 h. After washing and drying, the nanowire structure MnO2@Pt single-atom catalyst was finally obtained.

[0028] Implementation Results Example one, Figure 1 The powder X-ray diffraction (XRD) patterns of the dendritic MnOOH-MnO2@Pt single-atom catalyst prepared in Example 1 and the nanowire-structured MnO2@Pt single-atom catalyst prepared in Example 2 are shown below. Figure 1 It can be seen that the XRD diffraction peaks of the dendritic MnOOH-MnO2@Pt single-atom catalyst correspond to the standard cards of MnOOH (JCPDS#88-0649) and MnO2 (JCPDS#72-1982), and the XRD diffraction peaks of the nanowire-structured MnO2@Pt single-atom catalyst correspond to the standard card of MnO2 (JCPDS#72-1982). No diffraction peaks related to Pt were observed, indicating that Pt may exist in single-atom form.

[0029] two, Figure 2 This is a transmission electron microscope (TEM) image of the dendritic MnOOH-MnO2@Pt single-atom catalyst prepared in Example 1. Figure 2 TEM showed that MnOOH-MnO2@Pt is composed of nanowires and nanoparticles, proving that it has a dendritic structure. In aberration-corrected transmission electron microscopy (AC-TEM), it can be seen that the nanowires belong to the (-1 1 1) plane of MnOOH, and the nanoparticles belong to the (1 0 0) plane of MnO2. The bright spots indicate that Pt exists in the form of single atoms on the MnO2 nanoparticles. In the energy dispersive X-ray spectroscopy (EDS) mapping, it can be seen that Mn and O elements are uniformly distributed on the nanowires and nanoparticles, and Pt element is uniformly distributed on the nanoparticles, proving the successful preparation of MnOOH-MnO2@Pt.

[0030] three, Figure 3 This is a transmission electron microscope (TEM) image of the nanowire-structured MnO2@Pt single-atom catalyst prepared in Example 2. Figure 3TEM showed that MnO2@Pt is composed of nanowires, proving that it has a nanowire structure. In aberration-corrected transmission electron microscopy (AC-TEM), it can be seen that the nanowires belong to the (1 1 0) plane of MnO2, and the bright spots indicate that Pt exists in the form of single atoms on the MnO2 nanowires. In the energy dispersive X-ray spectroscopy (EDS) mapping, it can be seen that Mn, O and Pt elements are uniformly distributed on the nanowires, proving the successful preparation of MnO2@Pt.

[0031] Four, Figure 4 The images show the local electric field distribution of the dendritic MnOOH-MnO2@Pt single-atom catalyst prepared in Example 1 and the nanowire-structured MnO2@Pt single-atom catalyst prepared in Example 2. Figure 4 Simulation results show that the local electric field strength of the dendritic structure MnOOH-MnO2@Pt is 3.25 times stronger than that of the nanowire structure MnO2@Pt.

[0032] V. The performance of an aluminum-air battery was tested using a Chenhua electrochemical workstation 660E on the dendritic MnOOH-MnO2@Pt single-atom catalyst prepared in Example 1 and the nanowire MnO2@Pt single-atom catalyst prepared in Example 2 as cathode catalysts. Commercial aluminum alloy was used as the anode, and the catalyst prepared in this experiment was used as the air cathode at 6 mol·L⁻¹. -1 KOH solution was used as the electrolyte, and a peristaltic pump was used to circulate the electrolyte. Figure 5 Examples 1 and 2 were performed at 6 mol·L⁻¹ -1 Polarization curves and corresponding power density plots in KOH solution, and the nanowire-structured MnO2@Pt single-atom catalyst in 6 mol·L⁻¹ -1 Only 75 mW cm⁻¹ was observed in KOH solution. -2 The peak power density of the catalyst is significantly lower than that of the dendritic MnOOH-MnO2@Pt single-atom catalyst (120.3 mW / cm²). -2 ).

[0033] six, Figure 6 The dendritic MnOOH-MnO2@Pt single-atom catalyst prepared in Example 1 was tested at 50 mA·cm⁻¹. -2 The discharge curves at 50 mA cm⁻¹ show that the dendritic MnOOH-MnO₂@Pt single-atom catalyst can serve as the cathode of an aluminum-air battery at 50 mA cm⁻¹. -2 It has been running stably for 650 hours, demonstrating excellent stability.

[0034] seven, Figure 7Table 1 shows the specific capacity comparison data of the dendritic MnOOH-MnO2@Pt single-atom catalyst as the cathode electrocatalyst of the aluminum-air battery with other electrocatalysts reported in the literature: the specific capacity of Example 1 is 2381 mAh g. -1 ;1 corresponds to the literature Adv. Funct. Mater. 2025, 2501806, with a specific capacity of 857 mAh g. -1 ;2 corresponds to the literature Chemical Engineering Journal. 2024, 500, 157108, with a specific capacity of 2309 mAh g. -1 ;3 corresponds to the literature ACS Appl. Mater. Interfaces. 2024, 16, 37818, with a specific capacity of 2033.11 mAh g. -1 ;4 corresponds to the literature Journal of Alloys and Compounds. 2020, 824, 153950, with a specific capacity of 375 mAhg. -1 ;5 corresponds to the literature Diamond & Related Materials. 2022, 129, 109396, with a specific capacity of 1108 mAhg. -1 ;6 corresponds to the literature Langmuir. 2020, 36, 12954, with a specific capacity of 1630.1 mAh g. -1 ;7 corresponds to the literature Chemical Engineering Journal. 2020, 381, 122681, with a specific capacity of 482.8 mAh g. -1 ;8 corresponds to the literature International Journal of Hydrogen Energy. 2020, 45, 13025, with a specific capacity of 2181.66 mAh g. -1 ;9 corresponds to the literature Applied Surface Science. 2021, 564, 150474, with a specific capacity of 921 mAhg. -1 ;10 corresponds to the literature Sustainable Energy Fuels. 2023, 7, 3276, with a specific capacity of 1240 mAh g. -1 ;11 corresponds to the literature Applied Surface Science. 2023, 608, 155185, with a specific capacity of 1331.67 mAh g. -1;12 corresponds to the literature Dalton Trans. 2024, 53, 3713-3721, with a specific capacity of 1770 mAh g. -1 ;13 corresponds to reference J. Name. 2012, 00, 1-3, with a specific capacity of 1259 mAh g. -1 ;14 corresponds to the literature Adv. Energy Mater. 2020, 10, 2001378, with a specific capacity of 308 mAh g. -1 ;15 corresponds to the literature Applied Catalysis B: Environment and Energy. 2025, 372, 125329, with a specific capacity of 1895 mAh g. -1 ;16 corresponds to the literature Adv Energy Mater. 2023, 2303011, with a specific capacity of 935 mAh g. -1 ;17 corresponds to the literature ACS Catal. 2023, 13, 6661, with a specific capacity of 1273.3 mAh g. -1 ;18 corresponds to the literature Applied Catalysis B: Environmental. 2024, 342, 123407, with a specific capacity of 753.2 mAh g. -1 ;19 corresponds to the literature Chemical Engineering Journal. 2023, 456, 140858, with a specific capacity of 900 mAh g. -1 The value 20 corresponds to the literature NanoEnergy. 2024, 121, 109236, with a specific capacity of 809.3 mAh g⁻¹. -1 ; 21 corresponds to the literature ACS SustainableChem. Eng. 2019, 7, 1, 430, with a specific capacity of 585 mAh g. -1 ;22 corresponds to the literature Journal of Electroanalytical Chemistry. 2023, 941, 117552, with a specific capacity of 2257.48 mAh g. -1 ;23 corresponds to the literature Journal of Power Sources. 2021, 482, 229052, with a specific capacity of 1588 mAh g. -1 ; 24 corresponds to the literature ACS Appl. Mater. Interfaces. 2020, 12, 16512, with a specific capacity of 367.31 mAh g. -1; 25 corresponds to the literature ACS Appl. Mater. Interfaces. 2019, 11, 1, 578, with a specific capacity of 918 mAh g. -1 ; 26 corresponds to the literature Sustainable Energy Fuels. 2019, 3, 2717, with a specific capacity of 650 mAh g. -1 ; 27 corresponds to the literature Journal of Colloid and Interface Science. 2025, 686, 96, with a specific capacity of 812.3 mAh g. -1 ; 28 corresponds to the literature Journal of Power Sources. 2025, 641, 236859, with a specific capacity of 766.4 mAh g. -1 ; 29 corresponds to the literature ACS Applied Nano Materials. 2025, 7, 3487, with a specific capacity of 820.1 mAh g. -1 ; 30 corresponds to the literature Energy Storage Materials. 2025, 76, 104098, with a specific capacity of 583.7 mAh g. -1 ; 31 corresponds to the literature ACS Appl. Nano Mater. 2025, with a specific capacity of 375.5 mAh g. -1 ;32 corresponds to the literature International Journal of Hydrogen Energy. 2024, 69, 252, with a specific capacity of 1304 mAhg. -1 ; 33 corresponds to the literature Chemical Engineering Journal. 2024, 500, 157463, with a specific capacity of 769.78 mAh g. -1 ; 34 corresponds to the literature Energy Fuels. 2024, 38, 2, 1515, with a specific capacity of 409 mAh g. -1 The results show that the specific capacity of the dendritic MnOOH-MnO2@Pt single-atom catalyst as the cathode electrocatalyst for aluminum-air batteries is significantly better than that of currently reported electrocatalysts.

[0035] Table 1. Comparison of specific capacity of MnOOH-MnO2@Pt with other electrocatalysts reported in the literature. In summary, this invention presents a dendritic MnOOH-MnO2@Pt single-atom catalyst, which precisely synthesizes a Pt single-atom catalyst supported on MnO2 nanoparticles on MnOOH nanowires through a "Pt single-atom induction + in-situ co-generation" strategy. Compared with nanowire-structured MnO2@Pt catalysts, the dendritic MnOOH-MnO2@Pt exhibits a localized electric field enhancement effect, leading to reactant enrichment and thus improving the oxygen reduction reaction activity. Electrochemical testing results show that an aluminum-air battery using MnOOH-MnO2@Pt as the cathode has a specific capacity of 2381 mAh g⁻¹. -1 This is far superior to most reported cathode catalysts and can be achieved at 50 mA cm⁻¹. -2 Stable operation for 650 hours. This invention, by designing a catalyst with a unique dendritic structure, achieves effective control of the local microenvironment, providing a new approach for the design and synthesis of cathode catalysts for aluminum-air batteries.

[0036] The above description is merely an embodiment of the present invention and is not intended to limit the present invention in any way. The present invention can also have other embodiments based on the above structure and function, which will not be listed hereafter. Therefore, any simple modifications, equivalent changes, and alterations made by those skilled in the art to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A method for preparing a dendritic MnOOH-MnO2@Pt single-atom catalyst, characterized in that, Includes the following steps: (1) Disperse the amino acids evenly in water to form solution 1; (2) Add potassium permanganate to solution 1 and mix well to obtain solution 2; (3) Stir the solution 2 obtained in step (2), and after hydrothermal reaction, wash and dry to obtain MnOOH; (4) Disperse the platinum salt and the MnOOH obtained in step (3) in a mixed solution of water and ethylene glycol. After hydrothermal reaction, wash and dry to obtain MnOOH-MnO2@Pt catalyst.

2. The preparation method of the dendritic MnOOH-MnO2@Pt single-atom catalyst as described in claim 1, characterized in that, The amino acid in step (1) is any one or more of cysteine, serine, and threonine.

3. The preparation method of the dendritic MnOOH-MnO2@Pt single-atom catalyst as described in claim 1, characterized in that, The molar ratio of the amino acid to potassium permanganate is 1:1-6.

4. The preparation method of the dendritic MnOOH-MnO2@Pt single-atom catalyst as described in claim 1, characterized in that, The concentration of amino acids in step (1) is 0.0025-0.0075 mol / L; the concentration of potassium permanganate in step (2) is 0.0075-0.045 mol / L.

5. The preparation method of the dendritic MnOOH-MnO2@Pt single-atom catalyst as described in claim 1, characterized in that, The hydrothermal reaction temperature in step (3) is 140-200 ℃, and the reaction time is 8-24 h.

6. The preparation method of the dendritic MnOOH-MnO2@Pt single-atom catalyst as described in claim 1, characterized in that, In step (4), the volume ratio of water to ethylene glycol is between 3:1 and 1:

3.

7. The preparation method of the dendritic MnOOH-MnO2@Pt single-atom catalyst as described in claim 1, characterized in that, In step (4), the hydrothermal reaction temperature is 80-120 ℃ and the reaction time is 4-8 h.

8. The method for preparing the dendritic MnOOH-MnO2@Pt single-atom catalyst as described in claim 1, characterized in that, In step (4), the platinum salt is any one or more of potassium chloroplatinate, chloroplatinic acid, and sodium chloroplatinate; the platinum loading is 0.5-1.5 wt% of the catalyst mass.

9. A dendritic MnOOH-MnO2@Pt single-atom catalyst prepared by any of the preparation methods described in claims 1 to 8.

10. The application of the dendritic MnOOH-MnO2@Pt single-atom catalyst of claim 9 in the preparation of aluminum-air batteries.

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