Alginate fiber dynamically linked by host and guest supermolecules as well as preparation method and application of alginate fiber

Abstract

The invention discloses a host-guest supermolecule dynamically linked alginate fiber and a preparation method and application thereof, alginate is used as a substrate, and the surface of the alginate is dynamically linked with a three-dimensional network structure formed by a beta-cyclodextrin polymer and an adamantane polymer through host-guest interaction. The fiber has excellent hydrogen peroxide selectivity and stability, not only can effectively produce hydrogen peroxide, but also is expected to be applied to multiple fields due to the unique fiber structure.

Description

Technical Field

[0001] The present invention relates to the field of electrochemistry technology, and particularly to an alginate fiber utilizing non-covalent dynamic linkage of β-cyclodextrin and adamantane, a preparation method thereof, and an application of the fiber in the electrocatalytic reaction for producing hydrogen peroxide with two electrons. Background Art

[0002] As a versatile chemical, hydrogen peroxide exhibits indispensable application values in multiple fields such as chemical synthesis, environmental protection, and pharmaceutical manufacturing. However, in the traditional industrial production process of hydrogen peroxide, especially the anthraquinone method, despite its mature technology, it is accompanied by major challenges of high energy consumption and environmental pollution, which greatly limits its potential for sustainable development. In view of this, it is particularly important to explore more efficient and environmentally friendly hydrogen peroxide preparation technologies. In recent years, the method of preparing hydrogen peroxide by electrochemically reducing oxygen has gradually become a research hotspot due to its clean process, flexible and simple operation. This method not only has the potential to reduce energy consumption but also can significantly reduce the negative impact on the environment, providing the possibility for the green production of hydrogen peroxide.

[0003] Nevertheless, the key bottleneck faced by the current electrocatalytic oxygen reduction technology lies in the design and preparation of efficient and highly selective electrocatalysts. The existing electrocatalyst systems perform poorly in selectively catalyzing the reduction of oxygen to hydrogen peroxide rather than completely reducing it to water. At the same time, the insufficient stability during long-term operation and the high material cost also hinder its industrialization process. Therefore, developing new electrocatalysts, especially making breakthroughs in improving catalytic selectivity, enhancing catalytic stability, and reducing costs, is an urgent need in current research.

[0004] Alginate, as a natural polysaccharide polymer, has been widely used in fields such as biomedicine and the food industry due to its excellent biocompatibility and biodegradability. However, in the emerging interdisciplinary field of electrocatalysis, the unique physicochemical properties of alginate have not been fully explored and utilized. Its rich functional groups, good film-forming property, and adjustable structural characteristics provide potential opportunities for constructing high-performance electrocatalytic materials.

[0005] Supramolecular chemistry, as a science that utilizes non-covalent interactions (including various forces such as hydrogen bonds, π-π stacking, and host-guest interactions) to assemble and construct functional materials, has opened up a new perspective for the design of new electrocatalysts. In particular, host-guest interactions allow molecules or ions (guests) to be encapsulated in specific cavities or structures (hosts). This interaction can precisely control the microenvironment of the catalyst active sites, thus significantly affecting the path and efficiency of the catalytic reaction. Summary of the Invention

[0006] In view of the problems existing in the above-mentioned prior art, the present invention provides an alginate fiber based on host-guest supramolecular dynamic linkage, which has excellent hydrogen peroxide selectivity and stability. The alginate fiber is prepared by a wet spinning technique, and a host-guest supramolecular structure formed by β-cyclodextrin polymer and adamantane polymer is dynamically linked on its surface. This fiber can not only effectively produce hydrogen peroxide, but also its unique fiber structure is expected to be applied in multiple fields.

[0007] To achieve the above object, the present invention provides the following technical solutions:

[0008] A host-guest supramolecular dynamically linked alginate fiber, wherein the fiber uses alginate as a substrate, and a three-dimensional network structure formed by β-cyclodextrin polymer and adamantane polymer through host-guest interaction is dynamically linked on the surface.

[0009] A preparation method of the above-mentioned host-guest supramolecular dynamically linked alginate fiber, comprising the following steps:

[0010] (1) Prepare an aqueous solution of sodium alginate with a mass percentage of 1%-5%, add an aqueous solution of 1-ethyl-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS) to catalyze the carboxylamine reaction. Under nitrogen protection, dropwise add a solution of adamantylamine dissolved in N,N-dimethylformamide (DMF), react at room temperature, precipitate with tetrahydrofuran (THF) after the reaction, and freeze-dry to obtain adamantane-modified alginate powder;

[0011] (2) Dissolve the alginate powder and the adamantane-modified alginate powder prepared in step (1) in deionized water at a ratio of 1:(0.1-3) to prepare a spinning solution with a mass percentage of 2%-5%, and perform degassing treatment;

[0012] (3) Place the spinning solution prepared in step (2) in a syringe for wet spinning, and the coagulation bath solution is a divalent metal ion salt solution (such as calcium chloride) to form a solid alginate fiber, and then soak and dry it with ethanol to obtain the alginate fiber;

[0013] (4) Immerse the alginate fiber obtained in step (3) in a mixed solution containing β-cyclodextrin dimer, adamantane tetramer, deionized water and dichloromethane, heat and stir at 40 °C for 30 minutes, then cool to room temperature and continue to stir for 24 hours to obtain a host-guest supramolecular dynamically linked alginate fiber.

[0014] Specifically, the β-cyclodextrin dimer is any one of the following, and the structural formulas are shown as formulas (Ⅰ) and (Ⅱ) below:

[0015]

[0016] Specifically, the structural formula of the adamantane tetramer is as shown in the following formula (Ⅲ):

[0017]

[0018] Specifically, in the step (4),

[0019] the mass ratio of the alginate fiber to the β-cyclodextrin dimer is 1:(0.01 - 5);

[0020] the mass ratio of the alginate fiber to the adamantane tetramer is 1:(0.01 - 5);

[0021] the mass ratio of the alginate fiber to deionized water is 1:(0.01 - 5);

[0022] the mass ratio of the alginate fiber to dichloromethane is 1:(0.01 - 5);

[0023] The present invention also provides an application of the host-guest supramolecular dynamic-linked alginate fiber in the field of electrocatalysis, particularly in the electrocatalytic reaction for the two-electron production of hydrogen peroxide.

[0024] The beneficial effects of the present invention are as follows:

[0025] (1) The present invention prepares an alginate fiber flexible substrate through a wet spinning technique, which has biocompatibility, environmental friendliness, and good safety;

[0026] (2) The present invention innovatively links host-guest supramolecules dynamically on the surface of the alginate fiber, and the preparation process is simple and easy for large-scale preparation;

[0027] (3) The host-guest fiber material prepared by the present invention has been practically applied in the field of electrocatalysis, achieving a hydrogen peroxide production rate as high as 9.30 mol g -1 cat h -1 and a Faraday efficiency of 99.67%. Description of the Drawings

[0028] Figure 1 It is a scanning electron microscope image of the alginate fiber prepared in Example 1.

[0029] Figure 2 It is a schematic structural diagram of the host-guest supramolecular dynamic-linked alginate fiber SA-HG-ETB prepared in Example 1.

[0030] Figure 3 It is a scanning electron microscope image of the host-guest supramolecular dynamic-linked alginate fiber SA-HG-ETB prepared in Example 1.

[0031] Figure 4 It is a high-resolution transmission image of the host-guest supramolecular dynamic-linked alginate fiber SA-HG-ETB prepared in Example 1.

[0032] Figure 5 Electrochemical performance diagram of the host-guest supramolecular dynamically linked algal fiber SA-HG-ETB prepared in Example 1.

[0033] Figure 6 Electrochemical performance diagram of the host-guest supramolecular dynamically linked algal fiber SA-HG-ETB prepared in Example 1. Detailed implementation manners

[0034] In order to enable those skilled in the art to better understand the technical solutions of the present invention, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Based on the embodiments in this application, other similar embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of this application.

[0035] Example 1:

[0036] Example 1: This example relates to a preparation method of an algal fiber based on host-guest supramolecular dynamic linkage, and the specific steps are as follows:

[0037] (1) Prepare an aqueous sodium alginate solution with a mass percentage of 2%, add an aqueous solution of EDC and NHS to catalyze the carboxyl-amine reaction. Under nitrogen protection, then dropwise add a 2-equivalent solution of adamantylamine dissolved in DMF, react at room temperature for 24 hours, precipitate with THF, and freeze-dry to obtain adamantane-modified sodium alginate powder;

[0038] (2) Dissolve the sodium alginate powder and the adamantane-modified sodium alginate powder in step (1) in a ratio of 1:0.5 in deionized water to prepare a spinning solution with a mass percentage of 3%, and perform degassing treatment;

[0039] (3) Place the spinning solution obtained in step (2) in a 10 mL syringe for wet spinning, set the extrusion speed to 0.5 mL / min, and the coagulation bath solution is calcium chloride solution to form solid calcium alginate fiber. After crosslinking for 2 hours, soak in ethanol for 4 hours, and dry at 50 °C for 8 hours to obtain adamantane-grafted algal fiber;

[0040] (4) Immerse 50.0 mg of the adamantane-grafted algal fiber obtained in step (3) into a mixed solution containing 99.6 mg of β-cyclodextrin dimer (structural formula Ⅰ), 9.8 mg of adamantane tetramer, 3 mL of deionized water and 300 μL of dichloromethane. Stir at 40 °C for 30 minutes, then cool to room temperature and continue to stir for 24 hours to obtain the host-guest supramolecular dynamically linked algal fiber SA-HG-ETB.

[0041] Example 2: This example relates to a method for preparing algal fiber based on host-guest supramolecular dynamic linkage, and the specific steps are as follows:

[0042] (1) Prepare an aqueous sodium alginate solution with a mass percentage of 2%, add aqueous solutions of EDC and NHS to catalyze the carboxylamine reaction. Under nitrogen protection, dropwise add a 2-equivalent solution of adamantylamine dissolved in DMF, react at room temperature for 24 hours, precipitate with THF, and freeze-dry to obtain adamantane-modified sodium alginate powder;

[0043] (2) Dissolve sodium alginate powder and the adamantane-modified sodium alginate powder obtained in step (1) in deionized water at a ratio of 1:0.5 to prepare a spinning solution with a mass percentage of 3%, and perform degassing treatment;

[0044] (3) Place the spinning solution obtained in step (2) in a 10 mL syringe for wet spinning, set the extrusion speed to 0.5 mL / min, and use calcium chloride solution as the coagulation bath solution to form solid calcium alginate fiber. After crosslinking for 2 hours, soak in ethanol for 4 hours, and dry at 50 °C for 8 hours to obtain adamantane-grafted algal fiber;

[0045] (4) Immerse 50.0 mg of the adamantane-grafted algal fiber obtained in step (3) into a mixed solution containing 98.8 mg of β-cyclodextrin dimer (structural formula Ⅰ), 9.8 mg of adamantane tetramer, 3 mL of deionized water, and 300 μL of dichloromethane. Stir at 40 °C for 30 minutes, then cool to room temperature and continue stirring for 24 hours to obtain host-guest supramolecular dynamic linkage algal fiber SA-HG-BD.

[0046] This example uses a half-cell of a three-electrode system for testing. The prepared host-guest supramolecular dynamic linkage algal fiber SA-HG-ETB is used as the working electrode, and the auxiliary electrode and reference electrode are a platinum electrode and a silver / silver chloride / potassium chloride saturated solution reference electrode, respectively.

[0047] (1) Morphology test:

[0048] Figure 1 A large number of massive particles are exposed on the surface of the adamantane-grafted algal fiber; Figure 2 Adamantane adheres to the surface of the algal fiber, and after host-guest supramolecular dynamic linkage, the outer layer of the algal fiber is wrapped by massive substances; Figure 3 The surface of the host-guest supramolecular dynamic linkage algal fiber SA-HG-ETB is a porous layer; Figure 4 The host-guest supramolecule is successfully dynamically linked to the algal fiber.

[0049] (2) Performance test:

[0050] Figure 5Electrochemical performance characterization diagram of seaweed fiber SA-HG-ETB with host-guest supramolecular dynamic linkage in an oxygen-saturated 0.1 M potassium hydroxide electrolyte system. The results show that SA-HG-ETB has excellent two-electron oxygen reduction performance. At an operating potential of 0.4 V vs. RHE, the selectivity of SA-HG-ETB for hydrogen peroxide reaches an optimal value of 99.20%, and its electron transfer number decreases to 2.02.

[0051] Figure 6 Hydrogen peroxide accumulation experiment of seaweed fiber SA-HG-ETB with host-guest supramolecular dynamic linkage. It can be observed that when operating at a current density of 80 mA cm -2 for one hour, SA-HG-ETB can continuously produce hydrogen peroxide at a stable electrode potential.

[0052] In addition, it should be understood that although this specification is described according to embodiments, not every embodiment only contains an independent technical solution. This narrative way of the specification is only for clarity. Those skilled in the art should regard the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A host-guest supramolecular dynamic linking seaweed fiber, characterized in that: The host-guest supramolecular dynamically linked alginate fiber is composed of alginate as a substrate, and the surface is dynamically linked with a three-dimensional network structure formed by β-cyclodextrin polymer and adamantane polymer through host-guest interaction.

2. A method for preparing seaweed fiber with dynamic host-guest supramolecular linkage as claimed in claim 1, characterized in that: The following steps are involved: (1) preparing a sodium alginate aqueous solution with a mass percentage of 1% to 5%, adding 1-ethyl-(3-dimethylaminopropyl) carbodiimide and N-hydroxysuccinimide aqueous solution to catalyze the carboxylation reaction. Under nitrogen protection, adding a solution of adamantane dissolved in N,N-dimethylformamide dropwise, reacting at room temperature, precipitating with tetrahydrofuran, and freeze-drying to obtain adamantane-modified alginate powder; (2) dissolving alginate powder and adamantane-modified alginate powder prepared in step (1) in deionized water in a ratio of 1:(0.1-3) to prepare a spinning solution of 2%-5% by mass, and performing a degassing treatment; (3) placing the spinning solution prepared in step (2) in a syringe for wet spinning, wherein the coagulation bath solution is a divalent metal ion salt solution, to form solid seaweed fibers, which are then soaked in ethanol and dried to obtain seaweed fibers; (4) Immersing the seaweed fiber obtained in step (3) in a mixed solution containing β-cyclodextrin dimer, adamantane tetramer, deionized water and dichloromethane, heating and stirring at 40° C. for 30 minutes, cooling to room temperature and continuing to stir for 24 hours, thereby obtaining seaweed fiber with host-guest supramolecular dynamic linkage.

3. The preparation method according to claim 2, characterized in that: The β-cyclodextrin dimer is any one of the following, and the structural formula is shown in the following formula (I) and formula (II):

4. The preparation method according to claim 2, characterized in that: The structural formula of the adamantane tetramer is shown in the following formula (III):

5. The preparation method according to claim 2, characterized in that: In the step (4), the mass ratio of the seaweed fiber to the β-cyclodextrin dimer is 1:(0.01-5).

6. The preparation method according to claim 5, characterized in that: The mass ratio of the seaweed fiber to the adamantane tetramer is 1:(0.01-5).

7. The preparation method according to claim 6, characterized in that: The mass ratio of seaweed fiber to deionized water is 1:(0.01-5).

8. The preparation method according to claim 7, characterized in that: The mass ratio of seaweed fiber to dichloromethane is 1:(0.01-5).

9. Use of the seaweed fiber with dynamic host-guest supramolecular linkage as claimed in claim 1 in the electrocatalytic reaction of producing hydrogen peroxide with two electrons.

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