Catalyst based on crystal platinum / amorphous vanadium oxide cluster-cluster heterostructure and preparation method and application thereof

Abstract

The invention provides a preparation method and application of a catalyst based on a crystal platinum / amorphous vanadium oxide cluster-cluster heterostructure. The preparation method comprises the following steps: S1, synthesizing an amorphous vanadium oxide cluster; s2, synthesizing a crystal platinum cluster; and S3, synthesizing the heterostructure catalyst. Through precise synthesis and interface engineering, precise assembly of amorphous vanadium oxide clusters and precise platinum clusters is realized, a highly dispersed and uniform heterogeneous interface is obtained, and the catalyst is endowed with excellent catalytic activity and stability in alkaline hydrogen oxidation reaction.

Description

Technical Field

[0001] This invention relates to the field of electrochemical technology, and in particular to a catalyst based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure, its preparation method, and its application. Background Technology

[0002] Hydrogen oxidation (HOR) is a core electrochemical process in hydrogen energy devices such as fuel cells. Platinum and its nanostructures have long been widely used in HOR catalysis due to their excellent catalytic activity. However, in alkaline media, traditional platinum-based catalysts face bottlenecks such as low catalytic efficiency, low utilization of precious metals, and poor stability. Therefore, improving the activity and stability of HOR catalysts under alkaline conditions while reducing the amount of precious metals used has become a pressing technical challenge in this field.

[0003] In recent years, heterostructure engineering has become an important means to improve catalytic performance. By precisely controlling the interface of different components, the electronic structure and reaction pathway can be improved, thereby enhancing catalytic efficiency. Amorphous vanadium oxide clusters possess unique disordered structures and abundant surface active sites, enabling them to form interfacial coupling with platinum clusters and achieve synergistic catalysis. However, the preparation of highly dispersed, well-defined, and precisely composed platinum cluster / amorphous vanadium oxide cluster heterostructure catalysts remains a significant challenge: on the one hand, traditional methods struggle to achieve precise cluster-scale construction and uniform interface distribution, resulting in limited utilization of active sites and uncontrollable structures; on the other hand, the structural modulation of amorphous vanadium oxide clusters and their interfacial electronic coupling mechanism with noble metals remain unclear, restricting their performance optimization in the field of electrocatalysis.

[0004] Therefore, there is an urgent need to develop a catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure, which can significantly improve the catalytic activity, stability and anti-toxicity of the catalyst by precisely controlling the size and loading position of platinum clusters, as well as the composition and distribution of amorphous vanadium oxide clusters. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a method for preparing and applying a catalyst based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure. Through precision synthesis and interface engineering, the accurate assembly of amorphous vanadium oxide clusters and precise platinum clusters is achieved, resulting in a highly dispersed and uniform heterostructure interface. This endows the catalyst with excellent catalytic activity and stability even in alkaline HOR.

[0006] The first objective of this invention is to provide a method for preparing a catalyst based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure, the method comprising: S1 Synthesis of Amorphous Vanadium Oxide Clusters: Ammonium vanadate was dissolved in deionized water and stirred until homogeneous. Dopamine hydrochloride and anhydrous ethanol were added sequentially, and ammonium hydroxide was added slowly while stirring continuously. After the reaction was completed, the first precipitate was obtained by centrifugation and washing. The first precipitate was then vacuum dried and subjected to a first high-temperature heat treatment under an argon atmosphere to obtain an amorphous vanadium oxide cluster support. S2 Synthesis of Crystalline Platinum Clusters: H2PtCl6·6H2O and small molecule organic ligands were added sequentially to a specific solvent, and the reaction was carried out under controlled temperature and stirring to obtain a mixed solution; then, a reducing agent was added dropwise to the mixed solution under vigorous stirring to carry out a reduction reaction. After the reaction was completed, the solution was centrifuged and washed to obtain a second precipitate; the second precipitate was then vacuum dried to obtain crystalline platinum clusters. S3 Synthesis of heterostructure catalyst: Amorphous vanadium oxide cluster support and crystalline platinum cluster are placed in a beaker in sequence, deionized water is added to the beaker, and the mixture is stirred continuously until homogeneous to obtain a primary mixture; the primary mixture is then dried using a rotary evaporator to obtain an advanced mixture; the advanced mixture is subjected to a third high-temperature heat treatment under an argon atmosphere to obtain a catalyst based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure.

[0007] Specifically, the mass ratio of ammonium vanadate to dopamine hydrochloride in step S1 is 2:3.5.

[0008] Specifically, the stirring reaction in step S1 takes 8-10 hours and the temperature is 25-30°C; the first high-temperature heat treatment takes 2-3 hours and the temperature is 450-800°C.

[0009] Specifically, the small molecule ligand in step S2 is any one or more of trimethylphosphine, glutathione, cysteine, and phenylethyl mercaptan; the reducing agent is any one or more of sodium borohydride, tert-butylamine methylborane, triethylboraneamine, and ascorbic acid; and the specific solvent is any one or more of anhydrous ethanol, chloropropane, cyclohexane, acetonitrile, and toluene.

[0010] Specifically, in step S2, the mass ratio of H2PtCl6·6H2O, the small molecule organic ligand, and the reducing agent is 102:230:55.

[0011] Specifically, the time for the temperature-controlled stirring reaction in step S2 is 2-3 hours, and the temperature is 0-50°C; the time for the reduction reaction is 5-6 hours, and the temperature is 0-50°C.

[0012] Specifically, in step S3, the mass ratio of the amorphous vanadium oxide cluster support to the crystalline platinum cluster is 4:3.

[0013] Specifically, the third high-temperature heat treatment in step S3 lasts for 10-12 hours and at a temperature of 450-800°C.

[0014] Specifically, the drying process in steps S1 to S3 is carried out at a temperature of 60 to 80°C for 10 to 12 hours.

[0015] The second objective of this invention is to provide a catalyst based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure obtained by the preparation method described above.

[0016] The third objective of this invention is to provide an application of the catalyst described above, based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure, as a catalyst for the hydrogen oxidation reaction at the anode of an alkaline hydrogen fuel cell.

[0017] Compared with the prior art, the beneficial effects of the present invention include: This invention proposes a heterostructure catalyst assembled from crystalline platinum clusters and amorphous vanadium oxide clusters. Highly dispersed and highly active platinum clusters and amorphous vanadium oxide clusters are obtained through two independent synthesis steps. A third step achieves precise assembly and interfacial coupling between the two, overcoming the drawbacks of single-step synthesis which struggles to guarantee cluster morphology and interfacial uniformity. This catalyst achieves a tight bond between amorphous vanadium oxide and crystalline platinum clusters. Utilizing the abundant defects and surface active sites of amorphous materials, combined with the superior electron transfer and catalytic capabilities of crystalline platinum, a heterostructure interface with particularly significant synergistic effects is designed. This catalyst exhibits high catalytic activity and excellent stability in alkaline HOR. This invention maximizes the utilization of platinum catalytic sites, which helps reduce the amount of precious metals used and lowers the cost of catalyst preparation. Through precise control of the ratio of organic ligands and reducing agents, as well as multi-step washing and drying processes, it ensures that the obtained clusters are uniform in size, well-dispersed, have few impurities, and have a clear interface structure. Furthermore, high-temperature heat treatment in a specific reducing gas environment further enhances the contact and electronic coupling between platinum clusters and amorphous vanadium oxide, thereby improving the interfacial stability and durability of the catalyst. The preparation method provided by this invention has clear process steps and adjustable key parameters. Through precise control of cluster size, composition and surface chemistry, it provides a general synthetic approach for developing multi-component composite catalysts and interfacial functional materials. The resulting catalyst has strong interfacial control capability and good scalability, which facilitates large-scale production and performance expansion, and can meet different electrocatalytic and energy application needs. Attached Figure Description

[0018] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings in the following description are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0019] Figure 1 HAADF-STEM image of the amorphous vanadium oxide cluster support prepared in Example 1 of this invention; Figure 2 SAED diffraction pattern of the amorphous vanadium oxide cluster support prepared in Example 1 of this invention; Figure 3 Aberration-corrected HAADF-STEM image of the catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 1 of this invention; Figure 4 (ad) are the elemental distribution diagrams of N, O, Pt, and V of the cluster-cluster heterostructure catalyst of crystalline platinum / amorphous vanadium oxide prepared in Example 1 of the present invention. Figure 5 TEM image of the catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 2 of this invention; Figure 6 This is a TEM image of the catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 4 of the present invention; Figure 7 This is a TEM image of the catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Comparative Example 1 of this invention. Figure 8 This is a TEM image of the catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Comparative Example 2 of this invention. Figure 9 Comparison of XRD diffraction curves of the catalysts prepared in Examples 1-2 and Comparative Examples 1-2 of this invention; Figure 10 The above are comparison graphs of the HOR polarization curves of the catalysts based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Examples 1-6 and Comparative Examples 1-2 of this invention at a rotation speed of 1600 rpm in 0.1 mol / L KOH saturated with hydrogen. Figure 11 The relative current-time response curves of the catalyst based on the crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 1 of the present invention, as well as the catalysts prepared in Comparative Examples 1 and 2, in a hydrogen-saturated 0.1 mol / L KOH solution. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. Unless otherwise defined, all technical and scientific terms used in this specification have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing specific embodiments only and is not intended to limit the present invention.

[0021] Example 1: Synthesis of amorphous vanadium oxide clusters (S1): 0.2 g ammonium vanadate was dissolved in 50 mL deionized water and stirred for 30 min. Then, 0.35 g dopamine hydrochloride and 100 mL anhydrous ethanol were added sequentially, and the mixture was stirred for another 30 min. Finally, 5 mL ammonium hydroxide was slowly added, and the mixture was stirred at 25 °C for 10 h. After the reaction was complete, the product was collected by centrifugation and washed several times with deionized water to obtain the first precipitate. The first precipitate was vacuum dried at 60 °C for 8 h, followed by a first high-temperature heat treatment at 550 °C for 2 h under an argon atmosphere to obtain the amorphous vanadium oxide cluster support, denoted as VO. x / NC; S2 Synthesis of Crystalline Platinum Clusters: 102 mg of H2PtCl6·6H2O and 230 mg of glutathione were added sequentially to 6.0 mL of deionized water, and the mixture was heated and stirred at 0 °C for 2 h to obtain a mixed solution. Subsequently, 2 mL of 0.725 mol / L NaBH4 aqueous solution was added dropwise to the mixed solution under vigorous stirring, and the reduction reaction was carried out at 0 °C for 5 h. After the reaction was completed, the product was collected by centrifugation and repeatedly washed with methanol to obtain a second precipitate. The second precipitate was vacuum dried at 60 °C for 12 h to obtain crystalline platinum clusters. S3 Synthesis of Heterogeneous Catalyst: 20 mg of amorphous vanadium oxide cluster support and 15 mg of crystalline platinum cluster were placed in a beaker, and 2 mL of deionized water was added to the beaker. After stirring continuously for 10 h, a primary mixture was obtained. The primary mixture was then dried using a rotary evaporator to obtain a higher mixture. The higher mixture was subjected to a third high-temperature heat treatment at 550 °C for 10 h under an argon atmosphere to obtain the catalyst based on the crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 1, denoted as Pt-VO. x / NC.

[0022] The catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 1 was characterized structurally. Figure 1 HAADF-STEM image of the amorphous vanadium oxide cluster support prepared in Example 1 of this invention; Figure 2 This is the SAED diffraction pattern of the amorphous vanadium oxide cluster support prepared in Example 1 of this invention; Figure 1-2 It can be inferred that the vanadium oxide support material has a typical amorphous structure and exhibits a distinct cluster structure, with an average particle size concentrated around 1.7 nm. Figure 3 Aberration-corrected HAADF-STEM image of the catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 1 of this invention; Figure 3 The aberration-corrected HAADF-STEM images show that most clusters in this catalyst have distinct cluster-cluster interfaces, which separate Pt and VO. x The clusters connect to form crystalline-amorphous nanostructures. The clearly visible lattice spacing (0.225 nm) is the (111) crystal plane of Pt clusters with short-range ordered atomic arrangement, while the amorphous material is inferred to be VO. x . Figure 4 (ad) are the elemental distribution diagrams of N, O, Pt, and V of the cluster-cluster heterostructure catalyst of crystalline platinum / amorphous vanadium oxide prepared in Example 1 of the present invention. Figure 4 The elemental mapping revealed the spatial distribution of Pt and V on the catalyst, indicating the presence of a tightly coupled Pt-VO2 matrix. x Cluster.

[0023] Example 2: Synthesis of amorphous vanadium oxide clusters (S1): 0.2 g ammonium vanadate was dissolved in 50 mL deionized water and stirred for 30 min. Then, 0.35 g dopamine hydrochloride and 100 mL anhydrous ethanol were added sequentially, and the mixture was stirred for another 30 min. Finally, 5 mL ammonium hydroxide was slowly added, and the mixture was stirred at 25 °C for 10 h. After the reaction was complete, the product was collected by centrifugation and washed several times with deionized water to obtain the first precipitate. The first precipitate was vacuum dried at 60 °C for 8 h, followed by a first high-temperature heat treatment at 700 °C for 2 h under an argon atmosphere to obtain the vanadium oxide cluster support, denoted as VO. x / NC; S2 Synthesis of Crystalline Platinum Clusters: 102 mg of H2PtCl6·6H2O and 230 mg of glutathione were added sequentially to 6.0 mL of deionized water, and the mixture was heated and stirred at 0 °C for 2 h to obtain a mixed solution. Subsequently, 2 mL of 0.725 mol / L NaBH4 aqueous solution was added dropwise to the mixed solution under vigorous stirring, and the reduction reaction was carried out at 0 °C for 5 h. After the reaction was completed, the product was collected by centrifugation and repeatedly washed with methanol to obtain a second precipitate. The second precipitate was vacuum dried at 60 °C for 12 h to obtain crystalline platinum clusters. S3 Synthesis of heterostructure catalyst: 20 mg of amorphous vanadium oxide cluster support and 15 mg of crystalline platinum cluster were placed in a beaker, and 2 mL of deionized water was added to the beaker. After stirring continuously for 10 h, a primary mixture was obtained. The primary mixture was then dried using a rotary evaporator to obtain a higher mixture. The higher mixture was subjected to a third high-temperature heat treatment at 550 °C for 10 h under an argon atmosphere to obtain the catalyst based on the crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 2.

[0024] The catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 2 was characterized structurally. Figure 5 This is a TEM image of the catalyst based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 2 of this invention; Figure 5 It can be seen that the catalyst exhibits a distinct cluster structure with an average particle size of around 1.7 nm, and most of the clusters in the catalyst have obvious cluster-cluster interfaces.

[0025] Example 3: Synthesis of amorphous vanadium oxide clusters (S1): 0.2 g ammonium vanadate was dissolved in 50 mL deionized water and stirred for 30 min. Then, 0.35 g dopamine hydrochloride and 100 mL anhydrous ethanol were added sequentially, and the mixture was stirred for another 30 min. Finally, 5 mL ammonium hydroxide was slowly added, and the mixture was stirred at 25 °C for 10 h. After the reaction was complete, the product was collected by centrifugation and washed several times with deionized water to obtain the first precipitate. The first precipitate was vacuum dried at 60 °C for 8 h, followed by a first high-temperature heat treatment at 550 °C for 2 h under an argon atmosphere to obtain the amorphous vanadium oxide cluster support, denoted as VO. x / NC; S2 Synthesis of Crystalline Platinum Clusters: 102 mg of H2PtCl6·6H2O and 230 mg of mercaptobenzoic acid were added sequentially to a mixed solvent of 6.0 mL deionized water and ethanol. The mixture was heated and stirred at 0 °C for 2 h to obtain a mixed solution. Subsequently, 2 mL of 0.725 mol / L ascorbic acid aqueous solution was added dropwise to the mixed solution under vigorous stirring, and the reduction reaction was carried out at 0 °C for 5 h. After the reaction was completed, the product was collected by centrifugation and repeatedly washed with methanol to obtain a second precipitate. The second precipitate was then vacuum dried at 60 °C for 12 h to obtain crystalline platinum clusters. S3 Synthesis of heterostructure catalyst: 20 mg of amorphous vanadium oxide cluster support and 15 mg of crystalline platinum cluster were placed in a beaker, and 2 mL of deionized water was added to the beaker. After stirring continuously for 10 h, a primary mixture was obtained. The primary mixture was then dried using a rotary evaporator to obtain a higher mixture. The higher mixture was subjected to a third high-temperature heat treatment at 550 °C for 10 h under an argon atmosphere to obtain the catalyst based on the crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 3.

[0026] Example 4: Synthesis of amorphous vanadium oxide clusters (S1): 0.2 g ammonium vanadate was dissolved in 50 mL deionized water and stirred for 30 min. Then, 0.35 g dopamine hydrochloride and 100 mL anhydrous ethanol were added sequentially, and the mixture was stirred for another 30 min. Finally, 5 mL ammonium hydroxide was slowly added, and the mixture was stirred at 25 °C for 10 h. After the reaction was complete, the product was collected by centrifugation and washed several times with deionized water to obtain the first precipitate. The first precipitate was vacuum dried at 60 °C for 8 h, followed by a first high-temperature heat treatment at 550 °C for 2 h under an argon atmosphere to obtain the amorphous vanadium oxide cluster support, denoted as VO. x / NC; S2 Synthesis of Crystalline Platinum Clusters: 102 mg of H2PtCl6·6H2O and 230 mg of cysteine ​​were added sequentially to 6.0 mL of deionized water, and the mixture was heated and stirred at 0 °C for 2 h to obtain a mixed solution. Subsequently, 2 mL of 0.725 mol / L sodium cyanoborohydride aqueous solution was added dropwise to the mixed solution under vigorous stirring, and the reduction reaction was carried out at 0 °C for 5 h. After the reaction was completed, the product was collected by centrifugation and repeatedly washed with methanol to obtain a second precipitate. The second precipitate was vacuum dried at 60 °C for 12 h to obtain crystalline platinum clusters. S3 Synthesis of heterostructure catalyst: 20 mg of amorphous vanadium oxide cluster support and 15 mg of crystalline platinum cluster were placed in a beaker, and 2 mL of deionized water was added to the beaker. After stirring continuously for 10 h, a primary mixture was obtained. The primary mixture was then dried using a rotary evaporator to obtain a higher mixture. The higher mixture was subjected to a third high-temperature heat treatment at 550 °C for 10 h under an argon atmosphere to obtain the catalyst based on the crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 4.

[0027] The catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 4 was structurally characterized. Figure 6 This is a TEM image of the catalyst based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 4 of this invention; Figure 7It can be seen that the catalyst exhibits a distinct cluster structure, with an average particle size concentrated around 2.0 nm.

[0028] Example 5: Synthesis of amorphous vanadium oxide clusters (S1): 0.2 g ammonium vanadate was dissolved in 50 mL deionized water and stirred for 30 min. Then, 0.35 g dopamine hydrochloride and 100 mL anhydrous ethanol were added sequentially, and the mixture was stirred for another 30 min. Finally, 5 mL ammonium hydroxide was slowly added, and the mixture was stirred at 25 °C for 10 h. After the reaction was complete, the product was collected by centrifugation and washed several times with deionized water to obtain the first precipitate. The first precipitate was vacuum dried at 80 °C for 8 h, followed by a first high-temperature heat treatment at 550 °C for 2 h under an argon atmosphere to obtain the amorphous vanadium oxide cluster support, denoted as VO. x / NC; S2 Synthesis of Crystalline Platinum Clusters: 102 mg of H2PtCl6·6H2O and 230 mg of phenylethyl mercaptan were added sequentially to 6.0 mL of deionized water, and the mixture was heated and stirred at 50 °C for 2 h to obtain a mixed solution. Subsequently, 2 mL of 0.725 mol / L NaBH4 aqueous solution was added dropwise to the mixed solution under vigorous stirring, and the reduction reaction was carried out at 50 °C for 5 h. After the reaction was completed, the product was collected by centrifugation and repeatedly washed with methanol to obtain a second precipitate. The second precipitate was vacuum dried at 80 °C for 12 h to obtain crystalline platinum clusters. S3 Synthesis of heterostructure catalyst: 20 mg of amorphous vanadium oxide cluster support and 15 mg of crystalline platinum cluster were placed in a beaker, and 2 mL of deionized water was added to the beaker. After stirring continuously for 10 h, a primary mixture was obtained. The primary mixture was then dried using a rotary evaporator to obtain a higher mixture. The higher mixture was subjected to a third high-temperature heat treatment at 800 °C for 10 h under an argon atmosphere to obtain the catalyst based on the crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 5.

[0029] Example 6: Synthesis of amorphous vanadium oxide clusters (S1): 0.2 g ammonium vanadate was dissolved in 50 mL deionized water and stirred for 30 min. Then, 0.35 g dopamine hydrochloride and 100 mL anhydrous ethanol were added sequentially and stirred for another 30 min. Finally, 5 mL ammonium hydroxide was slowly added and the mixture was stirred at 25 °C for 10 h. After the reaction was complete, the product was collected by centrifugation and washed several times with deionized water to obtain the first precipitate. The first precipitate was vacuum dried at 70 °C for 8 h, followed by a first high-temperature heat treatment at 550 °C for 2 h under an argon atmosphere to obtain the amorphous vanadium oxide cluster support, denoted as VO. x / NC; S2 Synthesis of Crystalline Platinum Clusters: 102 mg of H2PtCl6·6H2O and 230 mg of glutathione were added sequentially to 6.0 mL of deionized water, and the mixture was heated and stirred at 30 °C for 2 h to obtain a mixed solution. Subsequently, 2 mL of 0.725 mol / L NaBH4 aqueous solution was added dropwise to the mixed solution under vigorous stirring, and the reduction reaction was carried out at 30 °C for 5 h. After the reaction was completed, the product was collected by centrifugation and repeatedly washed with methanol to obtain a second precipitate. The second precipitate was vacuum dried at 70 °C for 12 h to obtain crystalline platinum clusters. S3 Synthesis of heterostructure catalyst: 20 mg of amorphous vanadium oxide cluster support and 15 mg of crystalline platinum cluster were placed in a beaker, and 2 mL of deionized water was added to the beaker. After stirring continuously for 10 h, a primary mixture was obtained. The primary mixture was then dried using a rotary evaporator to obtain an advanced mixture. The advanced mixture was subjected to a third high-temperature heat treatment at 800 °C for 10 h under a mixed atmosphere of H2 / Ar to obtain the catalyst based on the crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 5.

[0030] Comparative Example 1: Compared with Example 1, the difference is that a sulfuric acid solution was used to etch away the amorphous vanadium oxide clusters in the amorphous vanadium oxide cluster support to load platinum clusters.

[0031] Synthesis of amorphous vanadium oxide clusters in S1: 0.2 g ammonium vanadate was dissolved in 50 mL deionized water and stirred for 30 min. Then, 0.35 g dopamine hydrochloride and 100 mL anhydrous ethanol were added sequentially and stirred for another 30 min. Finally, 5 mL ammonium hydroxide was slowly added and the mixture was stirred at 25 °C for 10 h. After the reaction was complete, the product was collected by centrifugation and washed several times with deionized water to obtain the first precipitate. The first precipitate was vacuum dried at 60 °C for 8 h, followed by a first high-temperature heat treatment at 550 °C for 2 h under an argon atmosphere to obtain an amorphous vanadium oxide cluster support. The amorphous vanadium oxide cluster support was then placed in 0.5 M sulfuric acid solution and soaked at 80 °C for 24 h. After the reaction was complete, the support was thoroughly washed with deionized water until neutral and dried to obtain the vanadium-free carbon support material prepared in Comparative Example 1, denoted as NC support. S2 Synthesis of Crystalline Platinum Clusters: 102 mg of H2PtCl6·6H2O and 230 mg of glutathione were added sequentially to 6.0 mL of deionized water, and the mixture was heated and stirred at 0 °C for 2 h to obtain a mixed solution. Subsequently, 2 mL of 0.725 mol / L NaBH4 aqueous solution was added dropwise to the mixed solution under vigorous stirring, and the reduction reaction was carried out at 0 °C for 5 h. After the reaction was completed, the product was collected by centrifugation and repeatedly washed with methanol to obtain a second precipitate. The second precipitate was vacuum dried at 60 °C for 12 h to obtain crystalline platinum clusters. S3 Synthesis of heterostructure catalyst: 20 mg of NC support and 15 mg of crystalline platinum clusters were placed in a beaker, and 2 mL of deionized water was added to the beaker. After stirring continuously for 10 h, a primary mixture was obtained. The primary mixture was then dried using a rotary evaporator to obtain an advanced mixture. The advanced mixture was subjected to a third high-temperature heat treatment at 550 °C for 10 h under an argon atmosphere to obtain the catalyst based on the crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Comparative Example 1.

[0032] The catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Comparative Example 1 was structurally characterized. Figure 7 This is a TEM image of the catalyst prepared in Comparative Example 1 of the present invention; it can be seen that the catalyst exhibits a distinct cluster structure with an average particle size concentrated at around 1.9 nm.

[0033] Comparative Example 2: Compared with Example 1, the difference is that amorphous vanadium oxide clusters are not used as a carrier, but commercial carbon carrier materials are used to load platinum clusters.

[0034] Synthesis of crystalline platinum clusters (S1): 102 mg of H2PtCl6·6H2O and 230 mg of glutathione were added sequentially to 6.0 mL of deionized water, and the mixture was heated and stirred at 0 °C for 2 h to obtain a mixed solution. Subsequently, 2 mL of 0.725 mmol / L NaBH4 aqueous solution was added dropwise to the mixed solution under vigorous stirring, and the reduction reaction was carried out at 0 °C for 5 h. After the reaction was completed, the product was collected by centrifugation and repeatedly washed with methanol to obtain a second precipitate. The second precipitate was vacuum dried at 60 °C for 12 h to obtain crystalline platinum clusters. S2 Synthesis Catalyst: 20 mg of commercial carbon support material and 15 mg of crystalline platinum clusters were placed in a beaker, and 2 mL of deionized water was added to the beaker. After stirring continuously for 10 h, a primary mixture was obtained. The primary mixture was then dried using a rotary evaporator to obtain a higher mixture. The higher mixture was subjected to a third high-temperature heat treatment at 550 °C for 10 h under an argon atmosphere to obtain the composite catalyst based on crystalline platinum / commercial carbon support material prepared in Comparative Example 2.

[0035] The catalyst prepared in Comparative Example 2 was characterized structurally. Figure 8 The image shows a TEM image of the catalyst prepared in Comparative Example 2 of this invention; it can be seen that the catalyst exhibits obvious agglomeration, with an average particle size concentrated at around 6.3 nm.

[0036] Structural characterization Table 1 shows the Pt and V metal contents of the catalysts prepared in Examples 1-6 and Comparative Examples 1-2 of this invention, as determined by ICP-OES.

[0037] Table 1

[0038] It can be seen that the catalysts prepared in Examples 1-6 have similar Pt and V metal contents; while no obvious V metal is present in Comparative Examples 1-2.

[0039] Figure 9 These are comparison images of the XRD diffraction patterns of the catalysts prepared in Examples 1-2 and Comparative Examples 1-2 of this invention; Figure 9 It can be seen that after the amorphous vanadium oxide support prepared in Example 1 is loaded with Pt clusters, the catalyst Pt-VO x The XRD pattern of / NC consists of diffraction peaks from a face-centered cubic (fcc) Pt crystal, VO x The structure of the / NC support was well preserved. The XRD pattern of the vanadium oxide support loaded with Pt clusters prepared in Example 2 shows that crystalline V2O3 clusters were formed at this temperature, containing diffraction peaks composed of fcc-phase Pt crystals. The XRD pattern of Comparative Example 1 shows diffraction peaks composed of fcc-phase Pt crystals, with no obvious V species diffraction peaks, indicating that V species were removed. The XRD pattern of Comparative Example 2 shows diffraction peaks composed of fcc-phase Pt crystals, with a lower half-width compared to Examples 1 and Comparative Example 1, indicating an increase in Pt particle size, consistent with TEM results.

[0040] Performance testing The catalyst based on the crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure obtained in this embodiment was used as an alkaline hydroxide catalyst, and its electrochemical performance in the alkaline hydroxide reaction was tested. The method for preparing the supported electrode of this catalyst is as follows: 2 mg of the catalyst prepared in this embodiment was mixed with 980 μL of isopropanol and 20 μL of 5 wt.% Nafion solution, and ultrasonicated for 30 minutes to form a uniform catalyst ink. Subsequently, an appropriate amount of this ink was drop-coated onto the pretreated clean glassy carbon electrode surface using a microsyringe. The amount of catalyst ink coated on the electrode was determined based on the Pt loading of the anode. Finally, it was allowed to air dry at room temperature to form a uniform catalyst layer for testing.

[0041] Figure 10 The table shows a comparison of the HOR polarization curves of the catalysts based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructures prepared in Examples 1-6 and Comparative Examples 1-2 at a rotation speed of 1600 rpm in hydrogen-saturated 0.1 mol / L KOH. Based on these polarization curve data, the mass activity of each catalyst can be calculated using the KL equation. Relevant data are shown in Table 2. Table 2 presents the catalytic mass activity test data of the catalysts obtained in Examples 1-6 and the comparative examples as alkaline hydroxide catalytic materials.

[0042] Table 2

[0043] As can be seen from Table 2, the mass activity of the catalysts prepared in Examples 1-6 is higher than that of the catalysts prepared in the comparative examples. The catalyst prepared in Example 1 has the highest mass activity, reaching 2803 A / g, which proves that the catalysts based on the cluster-cluster heterostructure of crystalline platinum / amorphous vanadium oxide prepared in the examples of this invention can significantly improve the HOR catalytic performance.

[0044] Figure 11 The relative current-time response curves of the catalyst based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared in Example 1 of this invention and the catalysts of Comparative Examples 1-2 in a hydrogen-saturated 0.1 mol / L KOH solution are shown. Figure 11 It can be seen that the catalyst prepared in Example 1 showed an activity decay rate of 0.6% after a long period of chronoamperometry testing. Under the same testing conditions, the activity decay rates of Comparative Example 1 and Comparative Example 2 reached 23.4% and 29.7%, respectively. This indicates that the catalyst prepared in this example can significantly improve the catalyst's anti-agglomeration ability and enhance its durability through the crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure.

[0045] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for preparing a catalyst based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure, characterized in that, The preparation method includes: S1 Synthesis of Amorphous Vanadium Oxide Clusters: Ammonium vanadate was dissolved in deionized water and stirred until homogeneous. Dopamine hydrochloride and anhydrous ethanol were added sequentially, and ammonium hydroxide was added slowly while stirring continuously. After the reaction was completed, the first precipitate was obtained by centrifugation and washing. The first precipitate was then vacuum dried and subjected to a first high-temperature heat treatment under an argon atmosphere to obtain an amorphous vanadium oxide cluster support. S2 Synthesis of Crystalline Platinum Clusters: H2PtCl6·6H2O and small molecule organic ligands were added sequentially to a specific solvent, and the reaction was carried out under controlled temperature and stirring to obtain a mixed solution; then, a reducing agent was added dropwise to the mixed solution under vigorous stirring to carry out a reduction reaction. After the reaction was completed, the solution was centrifuged and washed to obtain a second precipitate; the second precipitate was then vacuum dried to obtain crystalline platinum clusters. S3 Synthesis of heterostructure catalyst: Amorphous vanadium oxide cluster support and crystalline platinum cluster are placed in a beaker in sequence, deionized water is added to the beaker, and the mixture is stirred continuously until homogeneous to obtain a primary mixture; the primary mixture is then dried using a rotary evaporator to obtain an advanced mixture; the advanced mixture is subjected to a third high-temperature heat treatment under an argon atmosphere to obtain a catalyst based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure.

2. The preparation method according to claim 1, characterized in that, The mass ratio of ammonium vanadate to dopamine hydrochloride in step S1 is 2:3.

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3. The preparation method according to claim 1, characterized in that, The stirring reaction in step S1 takes 8-10 hours and the temperature is 25-30°C; the first high-temperature heat treatment takes 2-3 hours and the temperature is 450-800°C.

4. The preparation method according to claim 1, characterized in that, The small molecule ligand in step S2 is any one or more of trimethylphosphine, glutathione, cysteine, and phenylethyl mercaptan; the reducing agent is any one or more of sodium borohydride, tert-butylamine methylborane, triethylboraneamine, and ascorbic acid; and the specific solvent is any one or more of anhydrous ethanol, chloropropane, cyclohexane, acetonitrile, and toluene.

5. The preparation method according to claim 1, characterized in that, The mass ratio of H2PtCl6·6H2O, small molecule organic ligand, and reducing agent in step S2 is 102:230:

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6. The preparation method according to claim 1, characterized in that, The time for the temperature-controlled stirring reaction in step S2 is 2-3 hours, and the temperature is 0-50℃; the time for the reduction reaction is 5-6 hours, and the temperature is 0-50℃.

7. The preparation method according to claim 1, characterized in that, In step S3, the mass ratio of the amorphous vanadium oxide cluster support to the crystalline platinum cluster is 4:3; the third high-temperature heat treatment lasts for 10-12 hours and is performed at a temperature of 450-800°C.

8. The preparation method according to claim 1, characterized in that, The drying process described in steps S1 to S3 is performed at a temperature of 60 to 80°C for 10 to 12 hours.

9. A catalyst based on a crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure prepared by any one of the preparation methods described in claims 1 to 8.

10. The application of the catalyst based on crystalline platinum / amorphous vanadium oxide cluster-cluster heterostructure as described in claim 9 as an alkaline hydroxide catalyst in hydrogen fuel cells.

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