Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalysts, methods of making and applications thereof

Abstract

This invention relates to a Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst, its preparation method, and its application, belonging to the field of electrocatalysis technology. The Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst is a Pt / AHESO / CHESO composite catalyst. In this catalyst, Pt exists as metallic Pt clusters, AHESO is an amorphous high-entropy spinel oxide, and CHESO is a crystalline high-entropy spinel oxide. This catalyst exhibits excellent catalytic activity in redox reactions (ORR) and oxygen evolution reactions (OER), demonstrating high oxygen electrocatalytic activity and stability. This invention's Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst balances oxygen electrocatalytic activity and stability, providing a new method for promoting the stable and efficient operation of zinc-air batteries.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalysis technology, specifically relating to a Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst, its preparation method, and its application. Technical Background

[0002] With the increasing global energy demand and the growing severity of environmental problems, the development of efficient and sustainable energy storage and conversion devices has become a key issue in scientific research. Aqueous zinc-air batteries are particularly promising due to their high theoretical energy density (1086 Wh / kg). -1 Zinc-air batteries are considered a promising next-generation electrochemical energy storage system due to their low cost, high safety, and environmental friendliness. However, the actual performance of zinc-air batteries is still limited by the intrinsically slow kinetics of the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) at the air cathode. The slow, multi-step electron transfer process leads to a significant increase in charge / discharge overpotential and exacerbates polarization, severely reducing the battery's energy conversion efficiency and long-term cycle stability. Therefore, exploring efficient and stable bifunctional ORR / OER electrocatalysts is a core challenge. Currently, aqueous zinc-air batteries commonly use noble metal-based cathode catalysts such as Pt / C+RuO2. Although these catalysts have relatively good catalytic activity, they are expensive, resource-scarce, and prone to aggregation, dissolution, or oxidation in strongly alkaline operating environments, making it difficult to achieve long-term ORR / OER stability, which severely restricts the large-scale commercial application of zinc-air battery cathode catalysts. Therefore, developing bifunctional oxygen electrocatalysts that combine high activity and high stability and can replace noble metals is particularly important.

[0003] Spinel oxides are considered promising non-noble metal oxygen electrocatalysts due to their flexible cation occupancy and tunable electronic structure. Building on this, high-entropy spinel oxides, as single-phase solid solutions composed of five or more metal cations, exhibit significant high-entropy effects, lattice distortion effects, cocktail effects, and multi-component synergistic effects, providing a richer distribution of active sites and optimized adsorption energies, making them ideal candidate materials for constructing high-performance bifunctional electrocatalysts. However, crystalline high-entropy spinel oxides have limited electrochemical active area and insufficient defects and interfacial sites, making it difficult to fully utilize the catalytic potential of multi-metal components. Further activation of the intrinsic catalytic activity and stability of high-entropy spinel oxides through amorphous / crystalline heterojunction interface regulation and synergistic anchoring of noble metal clusters remains a significant challenge. Currently, there are no reports on the application of Pt clusters anchored in the unique composite structure of amorphous-crystalline high-entropy spinel oxides for efficiently driving aqueous zinc-air batteries. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a Pt cluster-anchored amorphous high-entropy spinel oxide catalyst, its preparation method, and its applications, particularly in aqueous zinc-air batteries. This Pt cluster-anchored amorphous high-entropy spinel oxide catalyst is a Pt / AHESO / CHESO composite catalyst. Leveraging the abundant heterogeneous interfaces between the amorphous and crystalline high-entropy spinel oxides, and the synergistic anchoring effect of the Pt clusters, it exhibits excellent bifunctional ORR / OER catalytic activity and superior electrochemical stability. The preparation method of this Pt cluster-anchored amorphous high-entropy spinel oxide catalyst is simple and controllable, with low raw material costs, and shows promising practical application prospects in the field of high-performance aqueous zinc-air batteries.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention discloses a Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst with the molecular formula Pt / A-(ZnCoFeNiMn)3O4 / C-(ZnCoFeNiMn)3O4, abbreviated as Pt / AHESO / CHESO. The Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst consists of Pt cluster nanoparticles anchored on the amorphous layer (A-(ZnCoFeNiMn)3O4) on the surface of a crystalline high-entropy spinel oxide (C-(ZnCoFeNiMn)3O4).

[0006] In the (ZnCoFeNiMn)3O4, the mass percentage of each element Zn, Co, Fe, Ni, and Mn is between 5% and 35%, and the mass percentages of each element are similar. Preferably, the mass percentages are Zn: 15.58%, Co: 16.84%, Fe: 16.17%, Ni: 16.39%, and Mn: 15.25%, and the ratio of the sum of the moles of the five elements to the moles of O is 3:4.

[0007] The Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst exhibits an ORR catalytic performance with a half-wave potential of 0.82~0.85V and an OER catalytic performance with an overpotential of 260~280 mV.

[0008] The present invention discloses a method for preparing a Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst, comprising the following steps: S1: Prepare a polymetallic salt solution Based on the mass percentage of metal elements in the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst, the corresponding metal salt solution is selected and mixed to obtain a multi-metal salt mixed solution. S2: Complexation precipitation treatment The polymetallic salt mixture solution was continuously stirred to fully disperse it. Then, urea and ammonium fluoride were added dropwise to the polymetallic salt mixture solution to adjust the precipitation environment of the reaction system to make the pH value 9-10, and the solution became clear and transparent, so that the solution gradually formed a homogeneous polymetallic precursor mixture system. S3: Hydrothermal preparation of high-entropy spinel oxide precursor A hydrothermal reaction was carried out on a multi-metal precursor mixture system. The resulting product was washed, dried and ground multiple times to obtain a high-entropy spinel oxide precursor. S4: High-entropy spinel oxide was obtained by calcination. The high-entropy spinel oxide precursor was subjected to high-temperature calcination to induce a solid-state reaction of the multi-metal components and form a single-phase high-entropy spinel structure. After calcination, it was naturally cooled to room temperature to obtain crystalline high-entropy spinel oxide C-(ZnCoFeNiMn)3O4 (CHESO). S5: Constructing a Pt precursor adsorption system CHESO was dispersed in deionized water and ultrasonically treated to ensure uniform dispersion. Then, Pt precursor was added to allow the Pt precursor to fully contact and adsorb onto the CHESO surface, resulting in a CHESO mixed dispersion containing Pt precursor. S6: Pt clusters are reduced and anchored to form an amorphous-crystalline composite structure. A reducing agent solution was slowly added dropwise to a CHESO mixed dispersion containing a Pt precursor, causing the Pt precursor to be reduced in situ to metallic Pt clusters, which were then anchored on the surface of a high-entropy spinel oxide. During the reduction process, the surface of the CHESO underwent local structural reconstruction, forming an amorphous high-entropy spinel oxide layer A-(ZnCoFeNiMn)3O4 (AHESO), thus obtaining a Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst, namely Pt / AHESO / CHESO.

[0009] In step S1, the corresponding metal salt solutions are zinc-based, cobalt-based, iron-based, nickel-based, and manganese-based solutions. The zinc-based salt solution is selected from at least one of zinc chloride, zinc nitrate, zinc sulfate, or zinc acetate solutions, preferably zinc chloride. The cobalt-based salt solution is selected from at least one of cobalt chloride, cobalt nitrate, cobalt sulfate, or cobalt acetate solutions, preferably cobalt nitrate. The iron-based salt solution is selected from at least one of ferric chloride, ferric nitrate, or ferric sulfate solutions, preferably ferric nitrate. The nickel-based salt solution is selected from at least one of nickel chloride, nickel nitrate, nickel sulfate, or nickel acetate solutions, preferably nickel nitrate. The manganese-based salt solution is selected from at least one of manganese chloride, manganese nitrate, manganese sulfate, or manganese acetate solutions, preferably manganese chloride.

[0010] In S1, the polymetallic salt solution has a molar ratio of Zn:Co:Fe:Ni:Mn = 1:1:1:1:1; the molar concentrations of each metal salt solution are: Zn 1 mol / L, Co 1 mol / L, Fe 1 mol / L, Ni 1 mol / L, and Mn 1 mol / L. After mixing the metal salt solutions according to the above molar ratio, a polymetallic salt mixed solution containing five metal elements (Zn, Co, Fe, Ni, and Mn) is formed. Inductively coupled plasma atomic emission spectrometry (ICP-AES) analysis shows that the mass percentages of each metal element in the obtained high-entropy spinel oxide are as follows: W Zn =15.58%, W Co =16.84%, W Fe =16.17%, W Mn =15.25%, W Ni =16.39%. The test results show that the five metallic elements Zn, Co, Fe, Ni and Mn are relatively evenly distributed in the material, which is consistent with the compositional characteristics of multi-component high-entropy spinel oxides.

[0011] In S2, the polymetallic salt mixture solution is continuously stirred to ensure thorough dispersion for 20-30 minutes. Urea and ammonium fluoride are added sequentially, and stirring continues until the mixture is homogeneous for 1-3 hours to ensure sufficient complexation and dispersion of Zn, Co, Fe, Ni, and Mn polymetallic ions. The addition rate is 1 drop / 2-3 seconds. The molar ratio of the polymetallic salts is: urea:ammonium fluoride = 5:34:17.

[0012] In the S3 described above, the hydrothermal reaction is preferably carried out in a reaction vessel lined with polytetrafluoroethylene, the hydrothermal holding temperature is 120~200 ℃, preferably 160~180 ℃, and the holding time is 4~8 h, preferably 6 h.

[0013] In the S4 described above, the high-temperature calcination temperature is 300~500 ℃, preferably 400 ℃; the calcination holding time is 1~6 h, preferably 2 h.

[0014] In S5, the Pt precursor is selected from at least one of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, or platinum acetylacetonate, preferably chloroplatinic acid hexahydrate (H2PtCl6·6H2O), which is used for subsequent reduction to form Pt clusters.

[0015] In S5, the mass of Pt precursor added is determined based on the loading of Pt on crystalline high-entropy spinel oxide CHESO. The mass ratio of crystalline high-entropy spinel oxide CHESO to Pt precursor is 1:(1~2), with a preferred loading ratio of 1:1.3.

[0016] In step S6, a reducing agent solution is slowly added dropwise to the CHESO mixed dispersion of the Pt precursor. The reducing agent is preferably a NaBH4 solution with a molar concentration of 0.3~0.6 mol / L, preferably 0.5 mol / L. The molar ratio is Pt precursor:reducing agent = 25:(0.22~0.45), and the dropping rate is 1 drop / 3~5 seconds. After the addition is complete, stirring continues for 1~3 hours, preferably 2 hours, to allow the Pt precursor to be reduced in situ to metallic Pt clusters and anchored on the surface of the amorphous high-entropy spinel oxide.

[0017] The application of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst of the present invention as a cathode catalyst in an aqueous zinc-air battery shows that its ORR / OER bifunctional oxygen electrocatalytic performance is demonstrated by electrochemical testing. In KOH solution, the ORR half-wave potential can reach 0.82 V~0.85 V, and the OER overpotential can reach 260 mV~280 mV.

[0018] The Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst, its preparation method, and its application of the present invention have the following advantages compared to the prior art: 1. The Pt / AHESO / CHESO composite catalyst prepared by this invention combines the multi-metal synergistic effect of high-entropy spinel oxide, the defect regulation effect of the amorphous-crystalline heterostructure interface, and the high active site advantage of Pt clusters, which can effectively improve the ORR / OER bifunctional oxygen electrocatalytic performance.

[0019] 2. The preparation method of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst of the present invention adopts a combination of hydrothermal method and in-situ reduction method. The process is simple and controllable, the reaction conditions are mild and the operation is convenient, which is conducive to reducing the amount of precious metals used and the material cost.

[0020] 3. The Pt cluster-anchored amorphous high-entropy spinel oxide catalyst prepared in this invention can be used as a catalyst for ORR and / or OER catalytic reactions. It exhibits excellent ORR and / or OER oxygen electrocatalytic performance in KOH electrolyte, with relatively fast ORR / OER reaction kinetics. Electrochemical tests show that in KOH solution, the ORR half-wave potential can reach 0.82 V~0.85 V, and the OER overpotential can reach 260 mV~280 mV. Attached Figure Description

[0021] To more clearly illustrate the specific technical solutions of the embodiments of the present invention, the accompanying drawings required in the embodiments of the present invention will be described below. The following drawings are some embodiments of the present invention.

[0022] Figure 1The images show the X-ray polycrystalline diffraction (XRD) patterns of Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0023] Figure 2 The images show the Raman spectra of Example 1, Comparative Example 1, and Comparative Example 2.

[0024] Figure 3 These are field emission scanning electron microscope (SEM) images of Embodiment 1 and Comparative Example 2 of the present invention.

[0025] Figure 4 These are field emission transmission electron microscope (TEM) images of Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0026] Figure 5 The images shown are electron probe energy dispersive spectroscopy (EDS) diagrams of Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention.

[0027] Figure 6 The diffraction ring patterns (SAEDs) of Embodiment 1, Comparative Example 1, and Comparative Example 2 of the present invention are shown.

[0028] Figure 7 This is a comparison chart of the ORR process performance of Example 1, Comparative Example 1, Comparative Example 2 and Comparative Example 3 of the present invention.

[0029] Figure 8 The image shows the ORR stage Tafel slope plots for Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3.

[0030] Figure 9 The graph shows the electron transfer number and H2O2 yield for Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3.

[0031] Figure 10 The LSV curves of ORR after 10,000 cycles of voltammetry are shown for Embodiment 1 and Comparative Example 3 of the present invention.

[0032] Figure 11 This is a comparison chart of the linear current-voltage (LSV) curves of the OER stage for Embodiment 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 of the present invention.

[0033] Figure 12 The OER stage Tafel slope diagrams are for Embodiment 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 of the present invention.

[0034] Figure 13 The LSV curves of OER after 10,000 cycles of voltammetry curves in Example 1 and Comparative Example 3 of this invention are shown.

[0035] Figure 14 This is a schematic diagram of the 3D structure of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst prepared in this invention. Detailed Implementation

[0036] This invention provides a Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst and its preparation method. To make the purpose, technical solution, and effects of the invention clearer, the following provides a more detailed description of the invention. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the invention.

[0037] The testing equipment used for the catalytic performance testing of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst provided in this invention is the KOSTER CS350 testing equipment.

[0038] Example 1

[0039] A Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst is prepared by the following method: Based on the mass percentage of metal elements in the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst, 1 mol / L Zn(NO3)2·6H2O, 1 mol / L Co(NO3)2·6H2O, 1 mol / L Fe(NO3)3·9H2O, 1 mol / L Ni(NO3)2·6H2O and 1 mol / L Mn(NO3)2·6H2O solutions were added to 50 mL of deionized water and magnetically stirred until homogeneous to obtain 50 mL of multi-metal salt mixed solution.

[0040] Under stirring conditions, 34 mmol of urea and 17 mmol of ammonium fluoride were added dropwise to the polymetallic salt mixed solution. Urea first established a uniform and slow precipitation environment, and ammonium fluoride was then used to regulate the metal ion release rate and crystal morphology. The pH of the reaction system was adjusted to 9-10, and magnetic stirring was continued for 2 h to obtain the polymetallic precursor mixed system.

[0041] The obtained multi-metal precursor mixture was transferred to the inner liner of a polytetrafluoroethylene-lined reactor and subjected to hydrothermal reaction at 120 °C for 6 h. After the reaction was completed, the reactor was cooled. The resulting product was washed multiple times with deionized water and anhydrous ethanol, dried, and ground to obtain a high-entropy spinel oxide precursor.

[0042] The high-entropy spinel oxide precursor was then transferred to a resistance furnace and calcined at 400℃ for 2 h to obtain crystalline high-entropy spinel oxide C-(ZnCoFeNiMn)3O4, i.e., CHESO.

[0043] The obtained CHESO was dispersed in 60 mL of deionized water, and 0.25 mol H2PtCl6·6H2O was added. The mixture was then magnetically stirred for 2 h to allow the Pt precursor to be fully adsorbed onto the CHESO surface.

[0044] Subsequently, 7.5 mL of a 0.5 mol / L NaBH4 solution was slowly added dropwise under stirring for in-situ reduction. After the addition was complete, the reaction continued for 2 h to reduce the Pt precursor to Pt clusters and anchor them on the surface of amorphous high-entropy spinel oxide. After the reaction, the obtained product was washed and dried multiple times to obtain the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide composite catalyst, namely Pt / A-(ZnCoFeNiMn)3O4 / C-(ZnCoFeNiMn)3O4, abbreviated as Pt / AHESO / CHESO. This Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst consists of Pt cluster nanoparticles anchored on the amorphous layer (A-(ZnCoFeNiMn)3O4) on the surface of crystalline high-entropy spinel oxide (C-(ZnCoFeNiMn)3O4). A schematic diagram of its structure is shown below. Figure 14 .

[0045] Using Pt / AHESO / CHESO as the cathode catalyst in an aqueous zinc-air battery, its ORR / OER bifunctional oxygen electrocatalytic performance is as follows: In the ORR process, the catalytic performance of the Pt cluster-anchored amorphous high-entropy spinel oxide catalyst was tested using a rotating ring-disk electrode (RRDE) device in oxygen-saturated 0.1 mol / L KOH electrolyte. The results are as follows: half-wave potential is 0.83 V, and Tafel slope is 81.0 mV dec. -1 The number of electrons transferred is 4, the yield of H2O2 is less than 5%, and after 10,000 cyclic voltammetric scans (CV), the half-wave potential shifts to the left by only 10 mV.

[0046] In the OER process, the catalytic performance of the Pt cluster-anchored amorphous high-entropy spinel oxide catalyst was tested in a 1 mol / L KOH electrolyte as follows: overpotential value of 270 mV, Tafel slope of 50.27 mV. -1 After 10,000 CV cycles, the overpotential value shifted only 4 mV to the right.

[0047] Example 2

[0048] A Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst is prepared by the following method: Based on the mass percentage of metal elements in the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst, 1 mol / L Zn(NO3)2·6H2O, 1 mol / L Co(NO3)2·6H2O, 1 mol / L Fe(NO3)3·9H2O, 1 mol / L Ni(NO3)2·6H2O and 1 mol / L Mn(NO3)2·6H2O solutions were added to 50 mL of deionized water and magnetically stirred until homogeneous to obtain a multi-metal salt mixed solution.

[0049] Under stirring conditions, 34 mmol of urea solution and 17 mmol of ammonium fluoride solution were added dropwise to the polymetallic salt mixed solution to adjust the pH of the reaction system to 9-10. The mixture was then magnetically stirred for 2 h to obtain the polymetallic precursor mixed system.

[0050] The obtained multi-metal precursor mixture was transferred to the inner liner of a polytetrafluoroethylene-lined reactor and kept at 140 °C for 4 h. After the reaction was completed, the reactor was cooled with the furnace. The resulting product was washed, dried and ground to obtain a high-entropy spinel oxide precursor.

[0051] The high-entropy spinel oxide precursor was then transferred to a resistance furnace and calcined at 500°C for 2 h to obtain crystalline high-entropy spinel oxide (CHESO).

[0052] The obtained CHESO was dispersed in 60 mL of deionized water, and 0.25 mol H2PtCl6·6H2O was added. The mixture was then magnetically stirred for 2 h to allow the Pt precursor to be fully adsorbed onto the CHESO surface.

[0053] Subsequently, NaBH4 solution was slowly added dropwise under stirring for in-situ reduction. After the addition was complete, the reaction continued for 3 h to reduce the Pt precursor to Pt clusters and anchor them on the surface of amorphous high-entropy spinel oxide. After the reaction was completed, the resulting product was washed and dried multiple times to obtain the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide composite catalyst, namely Pt / AHESO / CHESO.

[0054] Comparative Example 1 The preparation method is the same as in Example 1, except that H2PtCl6·6H2O is not added, and amorphous-crystalline high-entropy spinel oxide A-(ZnCoFeNiMn)3O4 / C-(ZnCoFeNiMn)3O4, i.e. AHESO / CHESO, can be obtained.

[0055] Comparative Example 2 The preparation method is the same as in Example 1, except that H2PtCl6·6H2O and NaBH4 are not added, and crystalline high-entropy spinel oxide A-(ZnCoFeNiMn)3O4, i.e., AHESO, can be obtained.

[0056] Comparative Example 3 Commercial Pt / C+RuO2 catalyst was used as comparative example 3.

[0057] Comparative Example 4 Similar to Example 1, except that only 34 mmol of urea was added to the polymetallic salt mixed solution to synthesize a non-nanoflower-like high-entropy spinel oxide structure.

[0058] Comparative Example 5 Similar to Example 1, except that adding only 17 mmol of ammonium fluoride to the polymetallic salt mixed solution will not synthesize high-entropy spinel oxide.

[0059] Comparative Example 6 Similar to Example 1, except that when 17 mmol of ammonium fluoride is added to the polymetallic salt mixed solution followed by 34 mmol of urea, a nano-flower-like high-entropy spinel oxide structure is formed.

[0060] Comparative Example 7 Similar to Example 1, the difference is that when a reducing agent solution is rapidly added to the CHESO mixed dispersion containing the Pt precursor, the reaction becomes very vigorous and uneven, affecting the Pt loading, resulting in larger Pt particle size and weaker interfacial bonding.

[0061] Test Example 1 The structural characterization of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalysts is as follows; Figure 1 The X-ray polycrystalline diffraction (XRD) patterns of Examples 1, Comparative Examples 1, and Comparative Examples 2 of this invention are shown. The XRD diffraction peaks of Examples 1, Comparative Examples 1, and Comparative Examples 2 all match the diffraction peaks of the Fe3O4 standard card (PDF#01-071-4918), exhibiting spinel cubic structure characteristics, corresponding to the (220), (311), (331), (422), (511), and (440) crystal planes, respectively. The (111), (200), and (220) diffraction peaks of Example 1 correspond to the Pt standard card (PDF#04-0802). The spinel diffraction peaks of Example 1 are significantly weakened, confirming the presence of an amorphous phase in Example 1.

[0062] Figure 2 These are the Raman spectra of Example 1, Comparative Example 1, and Comparative Example 2 of the present invention. They confirm that the high-entropy material has a spinel oxide structure.

[0063] Figure 3 The field emission scanning electron microscope (SEM) images of Example 1 and Comparative Example 2 of the present invention show that the surface of Example 1 after NaBH4 treatment exhibits a certain degree of roughness.

[0064] Figure 4 These are field emission transmission electron microscope (TEM) images of Examples 1, 1, and 2 of the present invention. Example 1 shows lattice fringe spacings of 0.196 nm and 0.297 nm, corresponding to the (311) and (220) crystal planes of the high-entropy spinel oxide, respectively. The lattice fringe spacings are 0.196 nm and 0.228 nm, corresponding to the (200) and (111) crystal planes of the Pt clusters, respectively. It can be observed that the Pt clusters are anchored on the surface of the amorphous high-entropy spinel oxide. Comparative Example 1 shows lattice fringe spacings of 0.143 nm and 0.1477 nm, corresponding to the (531) and (440) crystal planes of the high-entropy spinel oxide, respectively. Comparative Example 2 shows lattice fringe spacings of 0.147 nm and 0.142 nm, corresponding to the (440) and (531) crystal planes of the high-entropy spinel oxide, respectively.

[0065] Figure 5 The electron probe energy dispersive spectroscopy (EDS) diagrams of Example 1, Comparative Example 1, and Comparative Example 2 of this invention confirm that each metal element is uniformly distributed.

[0066] Figure 6 The images show the diffraction ring patterns (SAED) of Embodiment 1, Comparative Example 1, and Comparative Example 2 of this invention. It is shown that CHESO exhibits spinel lattice fringes and no amorphous reflection halos. AHESO / CHESO exhibits both spinel lattice fringes and amorphous reflection halos. Pt / AHESO / CHESO exhibits Pt cluster diffraction rings, spinel lattice fringes, and amorphous reflection halos.

[0067] The ORR / OER catalytic performance of Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalysts was tested. The preparation method for electrocatalyst ink is as follows: The catalyst ink consisted of a suspension of catalyst powder (5 mg), isopropanol (480 μL, 99.8%), and Nafion solution (20 μL, 5 wt%), sonicated for 2 hours. The loaded mass on the glassy carbon electrode (GC) was approximately 0.3 mg cm⁻¹. -2 .

[0068] The electrochemical catalytic performance testing system is as follows: Electrochemical measurements were performed on a Koster CS350 electrochemical workstation using a standard three-electrode system. A glassy carbon electrode (GC), a platinum sheet electrode, and a saturated calomel electrode (Hg / HgO) were used as the working electrode, counter electrode, and reference electrode, respectively.

[0069] Figure 7 The half-wave potential performance of the ORR process in Examples 1, 1, 2, and 3 of this invention is shown. ORR catalytic performance was tested in 0.1 mol / L KOH solution. It can be seen that Example 1 has the highest half-wave potential value (0.83 V), which is superior to the half-wave potential values ​​of Comparative Example 1 (0.67 V), Comparative Example 2 (0.64 V), and Comparative Example 3 (0.81 V), indicating that Example 1 has higher ORR catalytic performance.

[0070] Figure 8 The Tafel slope (81.0 mV dec) in Example 1 -1 (102.4 mV dec) lower than Comparative Example 1 -1 Comparative Example 2 (110.9 mV dec) -1 ) and Comparative Example 3 (94.9 mV dec -1 This indicates that Example 1 exhibits faster ORR reaction kinetics compared to the comparative example.

[0071] Figure 9 The electron transfer number in the catalytic process of Example 1, Comparative Example 1, and Comparative Example 2 was measured using RRDE. Example 1 exhibited a higher electron transfer number. The yield of H2O2 was less than 10% in the range of 0.2 V to 0.8 V. This indicates that the 4-electron transfer in Example 1 achieves more efficient oxygen electrocatalytic reaction kinetics, while suppressing the formation of the byproduct H2O2, reducing side reactions, and effectively improving catalytic performance and energy conversion efficiency.

[0072] Figure 10 The LSV curves of ORR after 10,000 cycles of cyclic voltammetry for Example 1 and Comparative Example 3 show a decrease of 10 mV in half-wave potential for Example 1 and a decrease of 21 mV in half-wave potential for Comparative Example 3. This indicates that Example 1 exhibits more stable electrochemical cycling performance during the ORR phase.

[0073] Figure 11 This paper compares the overpotential performance of the OER process in Examples 1, 1, 2, and 3 of this invention. The overpotential values ​​of the OER stage were tested in a 1 mol / L KOH solution. Example 1 had the lowest overpotential value (270 mV), which is lower than that of Comparative Example 1 (310 mV), Comparative Example 2 (360 mV), and Comparative Example 3 (300 mV), indicating that Example 1 has higher OER catalytic performance.

[0074] Figure 12 The Tafel slope (50.27 mV dec) in Example 1 -1 (), lower than the comparative example of 115.09 mV dec -1 Comparative Example 2 (124.49 mV dec) -1 ) and Comparative Example 3 (98.29 mV dec -1 This indicates that Example 1 exhibits faster OER reaction kinetics compared to the comparative example.

[0075] Figure 13 In Example 1, after 10,000 cyclic voltammetry cycles, the overpotential value of the OER curve increased by only 4 mV, while the overpotential value of Comparative Example 3 decreased by 58 mV. This demonstrates that Example 1 exhibits excellent electrochemical cycling stability during the OER stage.

[0076] In summary, this invention provides a method for preparing a Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst. The electrocatalyst prepared by this invention exhibits excellent ORR / OER bifunctional oxygen electrocatalytic performance as a zinc-air battery cathode catalyst, superior to the commercially available catalyst Pt / C+RuO2. It addresses the practical problem of slow kinetics in ORR / OER electrocatalysts, providing a scientifically effective method for developing zinc-air battery cathode catalysts.

[0077] The above description is merely an embodiment of some aspects of the present invention, but the present invention is not limited to the detailed methods described above. Any improvements made to the present invention by those skilled in the art, within the scope of the technology disclosed in the present invention, through equivalent substitutions or the addition of auxiliary components, should be covered within the protection scope of the present invention.

Claims

1. A Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst, characterized in that, The Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst is formed by Pt cluster nanoparticles anchored on the amorphous layer of the surface of crystalline high-entropy spinel oxide.

2. The Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst according to claim 1, characterized in that, The Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst has the molecular formula Pt / A-(ZnCoFeNiMn)3O4 / C-(ZnCoFeNiMn)3O4, abbreviated as Pt / AHESO / CHESO.

3. The Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst according to claim 2, characterized in that, The mass content of each element in the (ZnCoFeNiMn)3O4 is between 5% and 35%.

4. The preparation method of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst according to any one of claims 1-3, characterized in that, Includes the following steps: S1: Based on the mass percentage of metal elements in the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst, each metal salt raw material is dissolved in deionized water according to the proportion and mixed to obtain a multi-metal salt mixed solution. S2: Continue stirring the polymetallic salt mixed solution to fully disperse it. Add urea solution and ammonium fluoride solution dropwise to the polymetallic salt mixed solution until the pH value reaches 9-10 and the solution becomes clear and transparent. Continue stirring until the mixture is uniform to obtain the polymetallic precursor mixed system. S3: The multi-metal precursor mixture is transferred to a reactor for hydrothermal reaction and kept at a constant temperature. After cooling, it is washed and dried to obtain a high-entropy spinel oxide precursor. S4: High-entropy spinel oxide precursors are calcined at high temperature to obtain crystalline high-entropy spinel oxide C-(ZnCoFeNiMn)3O4; S5: Mix C-(ZnCoFeNiMn)3O4 with the Pt precursor in deionized water and stir until homogeneous to obtain a CHESO mixed dispersion containing the Pt precursor. S6: A reducing agent solution was slowly added dropwise to a CHESO mixed dispersion containing a Pt precursor to obtain a Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst.

5. The preparation method of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst according to claim 4, characterized in that, The selected metal salt solutions include cobalt-based salt solutions, iron-based salt solutions, manganese-based salt solutions, nickel-based salt solutions, zinc-based salt solutions, and platinum chlorate solutions.

6. The preparation method of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst according to claim 4, characterized in that, Molar ratio, sum of moles of polymetallic salts: urea: ammonium fluoride = 5:34:

17.

7. The preparation method of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst according to claim 4, characterized in that, In S3, the hydrothermal insulation temperature is 120~200 ℃ and the insulation time is 4~8 h; the high-temperature calcination temperature is 300~500 ℃ and the calcination insulation time is 1~6 h.

8. The preparation method of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst according to claim 4, characterized in that, The Pt precursor is selected from at least one of chloroplatinic acid, potassium chloroplatinate, sodium chloroplatinate, or platinum acetylacetonate; by mass ratio, crystalline high-entropy spinel oxide (CHESO):Pt precursor = 1:(1~2); the reducing agent is NaBH4 solution with a molar concentration of 0.3~0.6 mol / L; by molar ratio, Pt precursor:reducing agent = 25:(0.22~0.45).

9. The application of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst according to any one of claims 1-3 or the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst prepared by the preparation method according to any one of claims 4-8, characterized in that, Applications in ORR and / or OER electrocatalytic reaction processes.

10. The application of the Pt cluster-anchored amorphous-crystalline high-entropy spinel oxide catalyst according to claim 9, characterized in that, Electrochemical tests show that in potassium hydroxide solution, the ORR half-wave potential can reach 0.82 V~0.85 V, and the OER overpotential can reach 260 mV~280 mV.

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