A high-entropy cluster electrocatalyst, a preparation method and application thereof

Abstract

The application discloses a high-entropy cluster electrocatalyst and a preparation method and application thereof, and the high-entropy cluster electrocatalyst comprises a supported substrate of graphene oxide nanosheet and high-entropy clusters in a spinel configuration anchored on the surface of the graphene oxide, and the high-entropy clusters comprise a high-entropy spinel oxide structure composed of multiple metals, wherein the metals are more than five kinds of Co, Mn, Ni, Zn, Cu, Cr and Mg. The application realizes anchoring of the high-entropy oxide clusters on the surface of the graphene oxide, and the multi-component synergistic effect and the heterojunction charge optimization characteristics of the high-entropy oxide clusters improve seawater oxidation activity; the high-entropy stability characteristics and the strong carrier interaction promote the seawater oxidation stability of the catalyst, and the catalyst has better alkaline seawater oxidation performance.

Description

Technical Field

[0001] This invention relates to a high-entropy cluster electrocatalyst, its preparation method, and its application, particularly to a high-entropy cluster electrocatalyst, its preparation method, and its application in the electrolysis of seawater to produce hydrogen, belonging to the field of nanomaterials technology. Background Technology

[0002] Green hydrogen, as a clean energy source with zero emissions and excellent mass energy density, is driving the development of sustainable energy systems. Although water electrolysis for hydrogen production primarily relies on high-purity water, its large-scale application in the future will exacerbate freshwater scarcity in some regions. In contrast, seawater resources are abundant and more sustainable, but its complex composition (such as Cl-)... − These factors (such as...) lead to more stringent requirements for the activity and stability of anode catalysts during electrolysis. For example, seawater electrolysis faces the dual challenges of strong chloride ion adsorption and the chloride evolution reaction (ClER) affecting the anode catalyst, which severely hinders the oxygen evolution reaction (OER) and leads to catalyst corrosion and decreased catalytic efficiency. Existing seawater electrolysis anode catalyst designs focus on simple-component catalysts, which have the following shortcomings:

[0003] (1) Simple anode catalysts often face problems such as few active sites and unstable structure. Even if various strategies are used to design simple and highly active seawater electrolysis anode catalysts, the corrosion effect of chlorine species generated by the chlorine evolution reaction (ClER) during electrolysis on the catalyst layer is still the main challenge of seawater electrolysis under high current density.

[0004] (2) Due to their inherent electronic structure, simple catalysts lack both multi-metal synergistic regulation (such as d-band center regulation) to reduce the adsorption energy barrier of intermediates and the ability to enhance Cl adsorption through composite interface design (such as Cr2O3 modification layer). − The repulsive effect ultimately makes it difficult to synergistically optimize the oxidation activity and chlorine corrosion resistance of seawater.

[0005] Therefore, it is necessary to develop a novel high-entropy cluster electrocatalyst that simultaneously possesses high-entropy characteristics and a composite interface design. Summary of the Invention

[0006] Objective of the Invention: Addressing the problems existing in the prior art, one objective of this invention is to provide a novel high-entropy cluster electrocatalyst that simultaneously possesses high-entropy characteristics and a composite interface design. Utilizing the high specific surface area of ​​graphene oxide and the enrichment of dangling bonds induced by in-plane defects, various metal atoms spontaneously migrate to defect sites under entropy increase, forming high-entropy cluster structures, thereby significantly improving electrocatalytic performance. The high-entropy clusters anchored on the graphene oxide surface exhibit a spinel configuration. By controlling the type and proportion of selected metal elements in the precursor, high-entropy spinel clusters with different compositions can be flexibly constructed on the graphene oxide surface, achieving broad tunability of elemental composition. Another objective of this invention is to provide a method for preparing this high-entropy cluster electrocatalyst. A final objective of this application is to provide the application of this high-entropy cluster electrocatalyst in the electrolysis of seawater to produce hydrogen.

[0007] Technical solution: The present invention provides a high-entropy cluster electrocatalyst, comprising a supported substrate of graphene oxide nanosheets and high-entropy clusters with a spinel configuration anchored on the surface of graphene oxide. The high-entropy clusters include high-entropy spinel-type oxide structures composed of various metals.

[0008] Furthermore, the metals are five or more, including Co, Mn, Ni, Zn, Cu, Cr, and Mg.

[0009] The present invention discloses a method for preparing a high-entropy cluster electrocatalyst, comprising the following steps:

[0010] The graphene oxide dispersion was thoroughly mixed with a metal-soluble salt solution, heated and stirred, centrifuged, washed, and dried to obtain a high-entropy precursor; the high-entropy precursor was calcined at low temperature to obtain a spinel-type high-entropy cluster electrocatalyst supported on graphene oxide.

[0011] Further, the metal-soluble salts are metal acetates or nitrates. The molar ratio of graphene oxide to the total amount of various metal-soluble salts is 30:(0.5~3) mg / mol, preferably 30:1.5 mg / mol, and the molar ratio among the various metals is 1. Thorough mixing means stirring for 1~2 h. The heating and stirring temperature is 150~170 ℃, and the heating and stirring time is more than 2 h. Centrifuge at 8000~10000 rpm for more than 10 min, wash with ethanol more than three times, and dry at 60~80 ℃ for 10~12 h. Low-temperature calcination is carried out in air, with a heating rate of 2~5 ℃ / min, a low-temperature calcination temperature of 180~220 ℃, and a low-temperature calcination time of 5~10 h, preferably calcination at 200 ℃ for 10 h.

[0012] The present invention also includes the application of the high-entropy cluster electrocatalyst in the electrolysis of alkaline seawater to produce hydrogen.

[0013] Furthermore, in application, the pH of the alkaline seawater is 13-14, and the catalyst is coated on carbon paper with a loading of 2.0-3.0 mg / cm³. 2 .

[0014] This invention utilizes a negatively charged graphene oxide template for electrostatic adsorption of various metal ions, followed by low-temperature annealing to form highly ordered high-entropy oxide nanoclusters on the template surface. Compared to traditional high-entropy oxide nanoparticles and low-entropy cluster nanocatalysts, this material exhibits lower overpotential, a smaller Tafel slope, and excellent long-term stability in alkaline seawater oxidation reactions, providing inspiration for constructing high-performance and corrosion-resistant seawater electrolysis anode catalysts.

[0015] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0016] This invention utilizes the high specific surface area and dangling bond enrichment effect generated by in-plane defects in graphene oxide to drive a self-assembly process through entropy increase of various metals, successfully preparing high-entropy cluster materials with a spinel configuration on the surface of graphene oxide, significantly improving the oxidation activity and stability of seawater. This method has the following innovations and advantages:

[0017] (1) High-entropy oxide clusters were anchored on the surface of graphene oxide, and the multi-component synergistic effect and heterogeneous interface charge optimization characteristics improved the seawater oxidation activity; the high-entropy stability characteristics and strong support interaction promoted the stability of the catalyst in seawater oxidation.

[0018] (2) Compared with low-entropy oxide clusters and high-entropy oxide nanoparticles, high-entropy cluster catalysts formed by anchoring on the surface of graphene oxide templates have better alkaline seawater oxidation performance.

[0019] (3) The catalyst preparation method is universal. Different high-entropy cluster electrocatalysts can be obtained simply by adjusting the composition and ratio of the metal soluble salt. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the synthesis process of the high-entropy cluster nanocatalyst described in this invention;

[0021] Figure 2 The XRD pattern of the (CoMnNiZnCu)3O4 / C sample in Example 1;

[0022] Figure 3 This is a TEM image of (CoMnNiZnCu)3O4 / C in Example 1;

[0023] Figure 4 This is a STEM image of (CoMnNiZnCu)3O4 / C in Example 1;

[0024] Figure 5 The XRD pattern of the (CoMnNiZnCu)3O4 / C-150 sample in Example 2;

[0025] Figure 6 The TEM image of (CoMnNiZnCu)3O4 / C-250 in Example 2;

[0026] Figure 7 This is a comparison of the LSV curves of the (CoMnNiZnCu)3O4 / C, (CoMnNiZnCu)3O4 / C-180, and (CoMnNiZnCu)3O4 / C-220 samples in alkaline seawater in Example 3.

[0027] Figure 8 The XRD pattern of the (CoCrNiZnMg)3O4 / C sample in Example 4;

[0028] Figure 9 This is a TEM image of the (CoCrNiZnMg)3O4 / C sample in Example 5;

[0029] Figure 10 This is a comparison of the LSV curves of the (CoMnNiZnCu)3O4 / C, (CrMnNiZnCu)3O4 / C, and (CoCrNiZnMg)3O4 / C samples in alkaline seawater in Example 5.

[0030] Figure 11 This is a comparison of the LSV curves of the (CoMnNiZnCu)3O4 / C, (CrMnNiZnCu)3O4 / C-0.1, and (CrMnNiZnCu)3O4 / C-0.5 samples in alkaline seawater in Example 6.

[0031] Figure 12 The XRD pattern of Co3O4 / C in Comparative Example 1;

[0032] Figure 13 The TEM image of Co3O4 / C in Comparative Example 1;

[0033] Figure 14 The XRD pattern of (CoMnNiZnCu)3O4 in Comparative Example 2;

[0034] Figure 15 The TEM image of (CoMnNiZnCu)3O4 in Comparative Example 2;

[0035] Figure 16 This is a comparison of the LSV curves of (CoMnNiZnCu)3O4 / C, Co3O4 / C, and (CoMnNiZnCu)3O4 samples in alkaline seawater in Example 6.

[0036] Figure 17 This is a comparison of the Tafel slopes of the (CoMnNiZnCu)3O4 / C, Co3O4 / C, and (CoMnNiZnCu)3O4 samples in alkaline seawater in Example 6.

[0037] Figure 18 This is a chronopotential graph of (CoMnNiZnCu)3O4 / C in alkaline seawater in Example 6. Detailed Implementation

[0038] The technical solution of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0039] The concept of this invention is as follows: Based on the graphene oxide template method, this invention synthesizes a high-entropy cluster seawater oxidation electrocatalyst through oil bath and calcination reaction.

[0040] Utilizing the high specific surface area and in-plane defect structure of graphene oxide, metal ions are first adsorbed via electrostatic interactions to form a spatially uniformly distributed precursor. Subsequently, during oil bath and calcination, multi-element metal atoms spontaneously migrate to the defect sites of graphene oxide under entropy increase, forming high-entropy cluster structures. These clusters are then anchored to the graphene oxide surface through strong interactions, ultimately yielding a high-entropy cluster electrocatalyst supported on graphene oxide.

[0041] Combination Figure 1 The present invention discloses a method for preparing high-entropy cluster catalysts based on graphene oxide template method, comprising the following steps:

[0042] (1) Weigh out graphene oxide powder and disperse it in ethylene glycol solution and sonicate for 30 min to form a uniform graphene oxide dispersion.

[0043] (2) Select five or more soluble metal salts and dissolve them in 25 mL of ethylene glycol solution, sonicate for 30 min to form a homogeneous metal salt solution.

[0044] (3) Mix the graphene oxide dispersion and the metal salt solution and stir for 1-2 h to obtain a uniform suspension.

[0045] (4) The suspension was heated in an oil bath at 150~170 °C for 2~3 h, and the metal cations were chemically adsorbed on the surface of graphene oxide. Then, the high-entropy precursor was obtained by centrifugation, washing with ethanol and drying.

[0046] (5) The high-entropy precursor was heated to 150~200 ℃ in a muffle furnace at a heating rate of 2 ℃ / min and calcined for 5~10 h to successfully prepare high-entropy oxide cluster materials.

[0047] Example 1: Preparation of (CoMnNiZnCu)3O4 / C

[0048] (1) Weigh 30 mg of graphene oxide powder and disperse it in 75 mL of ethylene glycol solution and sonicate for 30 min to form a uniform graphene oxide dispersion (GO dispersion).

[0049] (2) Dissolve Zn(CH3COO)2·2H2O (0.3 mmol), Co(CH3COO)2·4H2O (0.3 mmol), Mn(CH3COO)2·4H2O (0.3 mmol), Cu(CH3COO)2·H2O (0.3 mmol) and Ni(CH3COO)2·4H2O (0.3 mmol) in 25 mL of ethylene glycol solution and sonicate for 30 min to form a homogeneous metal salt solution.

[0050] (3) Mix the GO dispersion in step (1) with the metal salt solution in step (2) and stir for 1-2 h to obtain a uniform suspension.

[0051] (4) The suspension was heated in an oil bath at 170 °C for 2 h. The cations were electrostatically adsorbed onto the surface of graphene oxide. The high-entropy precursor was then obtained by centrifugation, washing with ethanol and drying.

[0052] (5) The high-entropy precursor was heated to 200 °C in a muffle furnace at a heating rate of 2 °C / min and calcined for 10 h to successfully prepare a high-entropy cluster material, named (CoMnNiZnCu)3O4 / C.

[0053] XRD analysis was performed on (CoMnNiZnCu)3O4 / C prepared in this embodiment, and the results are as follows: Figure 2 As shown. By Figure 2 XRD analysis revealed that all peaks were characteristic of the spinel configuration, indicating that the catalyst (CoMnNiZnCu)3O4 / C synthesized in this application has a spinel oxide structure.

[0054] TEM analysis was performed on the (CoMnNiZnCu)3O4 / C prepared in this embodiment, and the results are as follows: Figure 3 As shown. By Figure 3 It can be seen that high-entropy spinel oxide clusters of crystalline phase were observed on the surface of amorphous graphene oxide.

[0055] STEM analysis was performed on the (CoMnNiZnCu)3O4 / C prepared in this embodiment, and the results are as follows: Figure 4 As shown. Figure 4 Furthermore, it can be observed that high-entropy spinel oxide nanocrystal bright spots exist on the surface of graphene oxide.

[0056] Example 2

[0057] The experimental procedure was the same as in Example 1, except that the high-entropy precursor was heated to 150 °C, 180 °C, 220 °C and 250 °C respectively in a muffle furnace at a heating rate of 2 °C / min, and calcined for 10 h. The high-entropy cluster materials obtained were named (CoMnNiZnCu)3O4 / C-150, (CoMnNiZnCu)3O4 / C-180, (CoMnNiZnCu)3O4 / C-220 and (CoMnNiZnCu)3O4 / C-250 respectively.

[0058] XRD and TEM analyses were performed on the four groups of high-entropy cluster materials prepared in this embodiment, and the results are as follows: Figure 5 and Figure 6 As shown. Figure 5 The XRD pattern of (CoMnNiZnCu)3O4 / C-150°C is shown. XRD analysis shows that (CoMnNiZnCu)3O4 / C-150°C has an amorphous structure. Figure 6 The TEM image of (CoMnNiZnCu)3O4 / C-250 is shown. TEM analysis shows that the graphene was completely burned off at 250℃.

[0059] Example 3: Performance Test of Seawater Electrolysis

[0060] The (CoMnNiZnCu)3O4 / C prepared in Example 1 and (CoMnNiZnCu)3O4 / C-180 and (CoMnNiZnCu)3O4 / C-220 prepared in Example 2 were subjected to OER linear sweep voltammetry tests under alkaline seawater conditions (1 M KOH + seawater, pH 14). In application, the catalyst material was coated on carbon paper with a loading of 2.5 mg / cm³. 2 The result is as follows Figure 7 As shown. From Figure 7 As can be seen, the (CoMnNiZnCu)3O4 / C synthesized at 200 °C in Example 1 exhibits the best performance, at 100 mA / cm². 2 The OER overpotential at that time was only 333 mV, which is better than that of (CoMnNiZnCu)3O4 / C-180 and (CoMnNiZnCu)3O4 / C-220 prepared in Example 2.

[0061] Example 4: Preparation of (CrMnNiZnCu)3O4 / C

[0062] The experimental procedure was the same as in Example 1, except that in step (2), Co(CH3COO)2·4H2O was replaced with Cr(CH3COO)2·6H2O dissolved in 25 ml of ethylene glycol solution. The final sample was named (CrMnNiZnCu)3O4 / C.

[0063] XRD analysis was performed on (CrMnNiZnCu)3O4 / C prepared in this embodiment, and the results are as follows: Figure 8 As shown. By Figure 8 It can be seen that (CrMnNiZnCu)3O4 / C has a spinel-type oxide structure.

[0064] Example 5: Preparation of (CoCrNiZnMg)3O4 / C

[0065] The experimental procedure was the same as in Example 1, except that in step (2), Mn(CH3COO)2·4H2O and Cu(CH3COO)2·H2O were replaced with Cr(CH3COO)2·6H2O and Mg(CH3COO)2·4H2O and dissolved in 25 ml of ethylene glycol solution. The final sample was named (CoCrNiZnMg)3O4 / C.

[0066] TEM analysis was performed on the (CoCrNiZnMg)3O4 / C prepared in this embodiment, and the results are as follows: Figure 9 As shown. By Figure 9 It can be seen that high-entropy spinel oxide clusters of crystalline phase were observed on the surface of amorphous graphene oxide.

[0067] The OER linear sweep voltammetry tests of (CrMnNiZnCu)3O4 / C prepared in Example 4, (CoCrNiZnMg)3O4 / C prepared in Example 5, and (CrMnNiZnCu)3O4 / C prepared in Example 1 were performed under alkaline seawater conditions (1 M KOH + seawater). The results are as follows: Figure 10 As shown. By Figure 10 The results show that the high-entropy oxide cluster materials (CrMnNiZnCu)3O4 / C and (CoCrNiZnMg)3O4 / C, prepared under the same preparation process, have seawater OER activity, but their electrocatalytic performance is not as good as that of (CoMnNiZnCu)3O4 / C with specific components in Example 1.

[0068] Example 6

[0069] The preparation process was the same as in Example 1, except that in step (2), the amount of the five metals added was changed from 0.3 mmol to 0.1 mmol and 0.5 mmol, respectively, and dissolved in 25 ml of ethylene glycol solution. The final samples were named (CrMnNiZnCu)3O4 / C-0.1 and (CrMnNiZnCu)3O4 / C-0.5, respectively.

[0070] The OER linear sweep voltammetry tests of (CrMnNiZnCu)3O4 / C-0.1 and (CrMnNiZnCu)3O4 / C-0.5 prepared in this embodiment under alkaline seawater conditions were performed, and the results are as follows: Figure 11 As shown. Figure 11 The OER linear sweep voltammetry tests under alkaline seawater conditions were compared under different feed rates. Figure 11 It is evident that (CrMnNiZnCu)3O4 / C-0.1 and (CrMnNiZnCu)3O4 / C-0.5 exhibit seawater OER activity, but their electrocatalytic performance is not as good as that of (CoMnNiZnCu)3O4 / C synthesized at a feed amount of 0.3 mmol.

[0071] Comparative Example 1

[0072] The preparation process is the same as in Example 1, except that in step (2), only 1 mmol of Co(CH3COO)2·4H2O was weighed and dissolved in 25 ml of ethylene glycol solution, and sonicated for 30 min to form a homogeneous metal salt solution. The resulting sample was named Co3O4 / C.

[0073] XRD analysis was performed on the Co3O4 / C prepared in this comparative study, and the results are as follows: Figure 12 As shown. By Figure 12 XRD analysis revealed that the synthesized catalyst Co3O4 / C has a spinel-type oxide structure.

[0074] TEM analysis was performed on the Co3O4 / C prepared in this comparative study, and the results are as follows: Figure 13 As shown. By Figure 13 As can be seen, spinel oxide clusters of crystalline phase can be observed on the surface of amorphous graphene oxide.

[0075] Comparative Example 2

[0076] The preparation process was the same as in Example 1, except that graphene oxide was not used as a template. In step (3), the metal salt solution was heated in an oil bath at 170 °C for 2 h, and then the precursor was obtained by centrifugation, washing with ethanol and drying. The precursor was heated to 200 °C in a muffle furnace at a heating rate of 2 °C / min and calcined for 10 h. The resulting sample was denoted as (CoMnNiZnCu)3O4.

[0077] XRD analysis was performed on (CoMnNiZnCu)3O4 prepared in this comparative example, and the results are as follows: Figure 14 As shown. Figure 14 XRD analysis revealed that the synthesized catalyst (CoMnNiZnCu)3O4 is a spinel-type oxide.

[0078] TEM analysis was performed on the (CoMnNiZnCu)3O4 prepared in this comparative study, and the results are as follows: Figure 15 As shown. By Figure 15 As can be seen, (CoMnNiZnCu)3O4 exhibits a typical nanoparticle morphology. (Comparison) Figure 3 and Figure 15 The (CoMnNiZnCu)3O4 / C sample exhibits a nanocluster morphology, while the (CoMnNiZnCu)3O4 sample exhibits a nanoparticle morphology.

[0079] Example 7

[0080] The OER linear sweep voltammetry tests of (CoMnNiZnCu)3O4 / C prepared in Example 1, Co3O4 / C prepared in Comparative Example 1, and (CoMnNiZnCu)3O4 prepared in Comparative Example 2 under alkaline seawater conditions were performed. Figure 16 As shown. By Figure 16 As can be seen, (CoMnNiZnCu)3O4 / C exhibits the best catalytic performance, indicating that anchoring high-entropy clusters with a spinel configuration on the surface of graphene oxide can significantly improve catalytic performance.

[0081] Figure 17 The chart compares the Tafel slopes of (CoMnNiZnCu)3O4 / C, Co3O4 / C, and (CoMnNiZnCu)3O4. (CoMnNiZnCu)3O4 / C has the smallest Tafel slope (39 mV dec). -1 This indicates its excellent seawater oxidation reaction kinetics.

[0082] Figure 18 (CoMnNiZnCu)3O4 / C under alkaline seawater conditions at 100 mA cm⁻¹ -2 The chronopotential curve at current density demonstrates its excellent seawater oxidation stability.

Claims

1. A high-entropy cluster electrocatalyst, characterized in that, The high-entropy cluster electrocatalyst comprises a supported substrate of graphene oxide nanosheets and high-entropy clusters anchored on the surface of graphene oxide exhibiting a spinel configuration. The high-entropy clusters include high-entropy spinel-type oxide structures composed of various metals.

2. The high-entropy cluster electrocatalyst according to claim 1, characterized in that, The metals are five or more of the following: Co, Mn, Ni, Zn, Cu, Cr, and Mg.

3. A method for preparing the high-entropy cluster electrocatalyst according to claim 1 or 2, comprising the following steps: The graphene oxide dispersion was thoroughly mixed with a variety of metal-soluble salt solutions, heated and stirred, centrifuged, washed, and dried to obtain a high-entropy precursor. High-entropy precursors were calcined at low temperatures to obtain spinel-type high-entropy cluster electrocatalysts supported on graphene oxide.

4. The preparation method according to claim 3, characterized in that, The metal-soluble salts are metal acetates or nitrates, and the mass molar ratio of graphene oxide to the total amount of various metal-soluble salts is 30:(0.5~3) mg / mol.

5. The preparation method according to claim 3, characterized in that, Thorough mixing means stirring for 1-2 hours, heating and stirring at a temperature of 150-170 ℃ for more than 2 hours.

6. The preparation method according to claim 3, characterized in that, Centrifuge at 8000~10000 rpm for more than 10 min, wash with ethanol more than three times, dry at 60~80℃ for 10~12 h.

7. The preparation method according to claim 3, characterized in that, The low-temperature calcination is carried out in air, with a heating rate of 2-5 °C / min, a calcination temperature of 180-220 °C, and a calcination time of 5-10 h.

8. The application of the high-entropy cluster electrocatalyst according to claim 1 or 2 in the electrolysis of alkaline seawater to produce hydrogen.

9. The application according to claim 8, characterized in that, The pH of alkaline seawater is 13 to 14.

10. The application according to claim 8, characterized in that, In application, the catalyst is coated onto carbon paper at a loading of 2.0 ~ 3.0 mg / cm³. 2 .

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