Multi-metal-based covalent organic framework electrocatalyst as well as preparation method and application thereof
Synthesis of polymetal-based covalent organic framework electrocatalysts through one-pot method has solved the environmental defects of thiophene plasticizers and the complex separation of indirect electrolyte products, and achieved efficient and environmentally friendly DBD synthesis, which is suitable for indirect electrocatalytic S-S bond construction, and promoted the green transformation of the rubber industry.
Patent Information
- Application Number
- CN202510519215.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-24
- Publication Date
- 2025-08-15
AI Technical Summary
In the prior art, thiophene plasticizers have biotoxicity and environmental protection defects, and the electrocatalysts in indirect electrolytic systems have complex product separation problems. The traditional DBD production process has low yields and high energy consumption, making it difficult to achieve efficient green synthesis of DBD.
A one-pot method was used to synthesize a polymetal-based covalent organic frame electrocatalyst, and TAPP-M was combined with terephthalaldehyde through Schiff base condensation reaction to prepare a covalent organic frame material with polymetallic synergistic effect for indirect electrocatalytic S-S bond construction.
It has achieved a polymetal-based covalent organic framework electrocatalyst with high porosity, good morphology and high catalytic activity. It is suitable for mass production and is used for indirect electrocatalytic S-S bond construction. It has simple product separation and excellent catalytic performance, which has promoted the industry's green transformation.
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Figure CN120485831A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of electrochemical catalytic materials, and in particular to a multi-metal-based covalent organic framework electrocatalyst, a preparation method thereof, and application thereof as an electrocatalyst in indirect electrocatalytic SS bond construction. Background Art
[0002] China has consistently led the global rubber consumption market since 2002, and the rubber additive industry, a key link in the supply chain, has simultaneously entered a period of rapid development. In rubber plasticization, plasticizers effectively reduce molecular chain entanglement and improve material workability. However, the currently used thiophene plasticizers have significant environmental drawbacks: their synthetic precursors are highly biotoxic, these compounds release irritating gases during processing, and their natural degradation cycle can take decades.
[0003] In contrast, 2,2'-diphenyltetraamidodisulfide (DBD) has become a globally recognized benchmark for green plasticizers due to its low toxicity, biodegradability, and FDA-certified safety. However, the existing production process of DBD faces bottlenecks such as low yield and high energy consumption, resulting in its market price being significantly higher than traditional products. The development of new processes for the efficient synthesis of DBD, such as indirect electrocatalytic SS bond construction, has become a core breakthrough in breaking cost barriers and promoting the green transformation of the industry. Organic electrosynthesis methods can basically be divided into two categories: direct electrolysis and indirect electrolysis. Direct electrolysis is the direct contact between the electrocatalyst and the electrode, while indirect electrolysis is achieved through electrocatalysis in the electrolyte. In the indirect electrolysis system, the kinetic inhibition associated with electron transfer at the electrode / electrolyte interface in traditional direct electrocatalysis can be eliminated. Generally speaking, the electrocatalysts commonly used in indirect electrolysis are homogeneous molecular catalysts (such as high-valent iodine, benzoquinone, halides, amines, etc.), but they still have the disadvantage of complex product separation. Covalent organic frameworks (COFs) are a class of porous materials with uniformly dispersed active sites. Their organic structural units can be designed to achieve multiple functions. Integrating multimetallic active sites into the porous framework may become an ideal electrocatalyst for indirect electrocatalysis.
[0004] High-entropy materials (HEMs) are typically oxides or alloys composed of multiple metals, forming a single phase driven by configurational entropy. The integration of multiple metal sites in HEMs can yield unique and superior material properties, making them promising high-performance materials for applications such as energy storage and conversion, sensing, and catalysis. To further expand the library of HEM-like materials, combining the concept of "high entropy" with porous crystalline materials is a worthy avenue for exploration. Due to the covalent nature of COFs, their inherent high porosity, light weight, good chemical inertness, and tunable structure / function make them a promising platform for HEM-like materials. While the synergistic effect of multiple metals can significantly enhance material performance, their integration into the COFs framework remains a technical bottleneck. Therefore, developing a COFs material with multiple metal active sites, high stability, and recyclability for indirect electrocatalytic SS bond construction is of great scientific significance and industrial application value. Summary of the Invention
[0005] The technical problem to be solved by the present invention is to overcome the above technical defects and provide a multi-metal synergistic effect, high porosity, good morphology and high catalytic activity, which can meet most of the important parameters required for practical applications and be used as an electrocatalyst for indirect electrocatalytic SS bond construction with excellent catalytic performance, a multi-metal based covalent organic framework electrocatalyst and its preparation method and use for indirect electrocatalytic SS bond construction.
[0006] To address the above technical issues, the present invention provides a technical solution: a multi-metal covalent organic framework electrocatalyst, primarily prepared by a one-pot Schiff base condensation reaction of multi-metal 5,10,15,20-tetrakis(4-aminophenyl)-21H,23H-porphyrin (TAPP-M, M = Cu, Co, Ni, Zn, Mn) with terephthalaldehyde (BDA). M is a combination of at least three transition metal elements.
[0007] Another aspect of the present invention discloses a method for preparing a multi-metal-based covalent organic framework electrocatalyst, comprising the following steps: dissolving TAPP-M and p-BDA in an organic solvent, synthesizing the solution in a one-pot process under vacuum conditions, and then cooling and filtering the solution to obtain the multi-metal-based covalent organic framework.
[0008] Preferably, the molar ratio of the reactants is TAPP-M:BDA:o-dichlorobenzene:n-butanol=0.03:0.06:8.5:8.5.
[0009] Preferably, the specific operation method under the vacuum state is to quickly freeze the tube and degas at 77K (liquid N2 bath) to achieve a vacuum degree of 100mTorr internal pressure.
[0010] Preferably, the filtration step comprises washing the precipitate three times with tetrahydrofuran and filtering the precipitate. The wet sample is then transferred to a Soxhlet extractor and washed with tetrahydrofuran for 24 hours. Finally, the sample is dried in a vacuum oven at 60° C. for 12 hours to obtain an activated sample.
[0011] Another aspect of the present invention provides the use of the multi-metal-based covalent organic framework electrocatalyst in the indirect electrocatalytic SS bond construction.
[0012] The advantages of this invention over existing technologies include: it utilizes a simple one-pot synthesis method to produce multimetallic covalent organic framework materials, resulting in a simple process, convenient operation, and suitability for mass production. The prepared material can be used for indirect electrocatalytic SS bond formation reactions and exhibits excellent catalytic performance. The preparation of this material provides a new strategy for the design and construction of electrocatalysts based on crystalline porous multimetallic covalent organic framework materials, breaking down the cost barriers for the industrial production of products undergoing indirect electrocatalytic SS bond formation and promoting the green transformation of the industry. BRIEF DESCRIPTION OF THE DRAWINGS
[0013] Figure 1 PXRD and SEM images of Quint-MMV-COF obtained in the present invention;
[0014] Figure 2 PXRD and SEM images of Tetra-MMV-COF obtained in the present invention;
[0015] Figure 3 PXRD and SEM images of Tri-1-MMV-COF obtained in the present invention;
[0016] Figure 4 PXRD and SEM images of Tri-2-MMV-COF obtained in the present invention;
[0017] Figure 5 PXRD and SEM images of Tri-3-MMV-COF obtained in the present invention
[0018] Figure 6 Property test diagrams of Quint-MMV-COF, Tetra-MMV-COF, Tri-1-MMV-COF, Tri-2-MMV-COF and Tri-3-MMV-COF obtained in the present invention. DETAILED DESCRIPTION
[0019] The following is combined with Figure 1-6 The present invention is described in further detail.
[0020] The present invention is further illustrated below by means of specific examples.
[0021] Example 1:
[0022] TAPP-M (TAPP-Cu, TAPP-Co, TAPP-Ni, TAPP-Zn, and TAPP-Mn in equal proportions), terephthalaldehyde, o-dichlorobenzene, n-butanol, and 6M glacial acetic acid were mixed in a Pyrex tube at a molar ratio of 0.03:0.06:8.5:8.5:1.2. After sonication for approximately 20 minutes, the mixture was rapidly frozen and degassed at 77 K (in a liquid N2 bath) to an internal vacuum pressure of 100 mTorr. After returning to room temperature, the mixture was heated at 120°C and allowed to stand for 72 hours. After cooling to room temperature, the mixture was thoroughly washed three times with tetrahydrofuran (THF), and the precipitate was filtered. The wet sample was then transferred to a Soxhlet extractor and washed with THF for 24 hours. Finally, the sample was dried in a vacuum oven at 60°C for 12 hours to obtain the activated sample.
[0023] The structure of the obtained Quint-MMV-COF was analyzed by X-Ray powder crystal diffraction (PXRD). Figure 1 ); the morphology and microstructure of the obtained Quint-MMV-COF were analyzed by scanning electron microscopy (SEM).
[0024] Example 2:
[0025] The preparation process and steps in this example are basically the same as those in Example 1 above, except that the TAPP-M used in this example is TAPP-Cu, TAPP-Co, TAPP-Ni, and TAPP-Zn in equal proportions. Tetra-MMV-COF is obtained. Figure 2 .
[0026] Example 3:
[0027] The preparation process and steps in this example are basically the same as those in Example 1 above, except that the TAPP-M used in this example is TAPP-Cu, TAPP-Co, and TAPP-Ni in equal proportions. Thus, Tri-1-MMV-COF is obtained. Figure 3 .
[0028] Example 4:
[0029] The preparation process and steps in this example are basically the same as those in Example 1 above, except that the TAPP-M used in this example is TAPP-Cu, TAPP-Co, and TAPP-Zn in equal proportions. Tri-2-MMV-COF is obtained. Figure 4 .
[0030] Example 5:
[0031] The preparation process and steps in this example are basically the same as those in Example 1 above, except that the TAPP-M used in this example is TAPP-Cu, TAPP-Ni, and TAPP-Zn in equal proportions. Thus, Tri-3-MMV-COF is obtained. Figure 5 .
[0032] The Quint-MMV-COF prepared in Example 1 was used for indirect electrocatalytic SS bond construction:
[0033] The indirect electrocatalytic SS bond construction electrocatalytic reaction is completed at room temperature using a standard two-electrode system. The electrolytic cell used in the electrochemical test is a closed single-cell electrolytic cell, and the anode and cathode are carbon paper with a size of 53mm*8mm*1.5mm. The SS coupling reaction of benzenethiol is used as a reaction model, and Quint-MMV-COF is used as a catalyst to synthesize symmetrical disulfides. During the test, acetonitrile, benzenethiol, tetrabutylammonium tetrafluoroborate and Quint-MMV-COF are added to a dry bottle in a molar ratio of 1:2:4:1 for room temperature electrocatalytic testing. The product yield was analyzed by nuclear magnetic resonance spectroscopy and recorded on a 500MHz (Bruker) instrument. 1 H NMR and 13 C NMR spectroscopy, with CDCl3( 1 H NMR is 7.26 ppm, 13 Hydrogen was detected and analyzed by gas chromatography (GC-7920) using a thermal conductivity detector (TCD) and nitrogen as the carrier gas.
[0034] At room temperature, the conditions were optimized with different currents and times. It was concluded that under the conditions of 3 h and 1 mA current, the yield of SS product reached 98.3 ± 0.6% in 3 h, and 1.6 mmol g -1 h -1 Under the optimized conditions, the recyclability of Quint-MMV-COF was studied to verify its feasibility for industrial application. After each cycle, Quint-MMV-COF was easily separated and could be reused in indirect electrochemical reactions after centrifugation, washing, and drying. After 6 cycles, no obvious catalyst deactivation was found, and the product yield remained at 89 ± 1.5% ( Figure 6 ).
[0035] To evaluate the versatility of the Quint-MMV-COF catalyst in the indirect electrocatalytic SS coupling reaction, extensive experiments were conducted using various substrates (Table 1). The environmentally friendly plasticizer DBD (14b) achieved an 80% yield in the indirect electrocatalytic SS coupling reaction, which has important economic significance for the development of the rubber industry. These results demonstrate that the indirect electrocatalytic system can simultaneously generate high-value-added SS coupling products and H2 in a single system. Quint-MMV-COF is a stable electrocatalyst with broad application prospects in the large-scale indirect electrocatalytic production of SS coupling products.
[0036] The present invention and its embodiments are described above. This description is not restrictive. The drawings show only one embodiment of the present invention, and the actual structure is not limited thereto. In short, if a person skilled in the art is inspired by this and, without departing from the purpose of the present invention, designs structures and embodiments similar to this technical solution without inventiveness, they shall fall within the scope of protection of the present invention.
Claims
1. A multi-metal-based covalent organic framework electrocatalyst, characterized by: The polymetallic 5,10,15,20-tetrakis(4-aminophenyl)-21H,23H-porphyrin (TAPP-M) was synthesized in one pot by a Schiff base condensation reaction with terephthalaldehyde (BDA) in an organic solvent.
2. The multi-metal-based covalent organic framework electrocatalyst according to claim 1, characterized in that: In the multi-metal-containing 5,10,15,20-tetrakis(4-aminophenyl)-21H,23H-porphyrin, M includes any combination of copper, cobalt, nickel, zinc, and manganese, and the organic ligand is selected from BDA.
3. The multi-metal-based covalent organic framework electrocatalyst according to claim 1, characterized in that: The organic solvents are o-dichlorobenzene and n-butanol.
4. The multi-metal-based covalent organic framework electrocatalyst according to claim 3, characterized in that: The molar ratio of the reactants is TAPP-M:BDA:o-dichlorobenzene:n-butanol=0.03:0.06:8.5:8.
5.
5. The method for preparing a multi-metal-based covalent organic framework electrocatalyst according to any one of claims 1 to 4, characterized in that: The following steps are involved: TAPP-M and BDA were dissolved in an organic solvent and kept at 120°C for 72 h under vacuum conditions. After the solution was dissolved, it was cooled and filtered to obtain a multi-metal-based covalent organic framework electrocatalyst.
6. The method for preparing a multi-metal-based covalent organic framework electrocatalyst according to claim 5, characterized in that: The operation method under the vacuum state is to quickly freeze the tube in a liquid nitrogen bath and degas it to achieve a vacuum degree of 100 mTorr internal pressure.
7. The method for preparing a multi-metal-based covalent organic framework electrocatalyst according to claim 1, characterized in that: The filtration includes washing the precipitate thoroughly with tetrahydrofuran three times and filtering the precipitate, transferring the wet sample to a Soxhlet extractor and washing it with tetrahydrofuran for 24 hours, and finally drying it in a vacuum oven at 60° C. for 12 hours to obtain an activated sample.
8. Use of the multi-metallic covalent organic framework electrocatalyst according to any one of claims 1 to 4 as a redox mediator in the indirect electrocatalytic SS bond construction.