Mesoporous-macroporous material based on single micelle amido induced self-assembly as well as preparation method and application of mesoporous-macroporous material

Abstract

The invention provides a mesoporous-macroporous material based on single micelle amido induced self-assembly. The invention further provides a preparation method of the mesoporous-macroporous material based on single micelle amido induced self-assembly. A single surfactant is adopted to prepare the hierarchical porous nanospheres. The invention also provides an application of the mesoporous-macroporous material based on single micelle amido induced self-assembly. The invention relates to a mesoporous-macroporous material based on single micelle amido induced self-assembly, which is characterized in that under a single micelle system formed by P123, 1, 2, 4-hydroxyhydroquinone is used as a precursor, ethylenediamine is used as an initiator, 1, 3, 5-trimethylbenzene is used as a pore-enlarging agent, and nanospheres with hierarchical pore channels of mesopores and macropores are self-assembled and synthesized. The mesoporous-macroporous material is prepared by adopting a single surfactant, namely P123 as a single micelle system, 1, 2, 4-hydroxyhydroquinone as a precursor, ethylenediamine as an initiator and 1, 3, 5-trimethylbenzene as a pore-enlarging agent. The multi-stage pore channel with mesopores and macropores can be prepared through the single surfactant.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of organic porous materials, in particular to a meso-macroporous material based on single-micelle amine group induced self-assembly and a preparation method and application thereof. BACKGROUND

[0002] Porous materials have attracted extensive attention in the fields of sensing, new energy, life science, etc. due to their regular pore structure, high specific surface area, low density, and good electrical conductivity (Prog. Polym. Sci., 2023, 142, 101691; Nat. Mater., 2015, 14, 763-774). According to the pore size, porous materials can be divided into microporous, mesoporous, and macroporous materials (ACS Central Sci., 2023, 9, 1499-1503). Meanwhile, porous materials can cover the entire range of pore sizes, forming a hierarchical pore structure (Chem. Rev., 2016, 116, 10983-11060). Different pore structures usually exhibit a double-pore model or even a triple-pore model. Compared with materials with a single pore structure, materials with a hierarchical pore structure have a lower density, a larger available space, and the connectivity of the multi-level pores, which exhibit the advantage of mass electron transfer (Adv. Energy. Mater., 2020, 10, 2002152). Different pore structures play a decisive role in the performance of porous materials, and the controllable regulation of the pore structure is a key scientific problem in this research field.

[0003] Currently, the main methods for preparing porous materials include spray pyrolysis, colloid-assisted assembly, spatially confined polymerization, and self-assembly (J. Am. Chem. Soc., 2017, 139, 1706-1713). Self-assembly offers a new approach for preparing porous materials with tunable pore sizes. This strategy, using micelles as pore-forming templates and inorganic or organic polymers as bulk materials, allows for the controlled preparation of porous materials with diverse structures. Numerous studies have shown that surfactants first form single micelles or aggregates of multiple micelles, which then aggregate with precursors or oligomers at the interface to form an ordered porous structure. By adjusting the preparation conditions, the size, structure, and morphology of the micelles can be adjusted, allowing for precise control of the pore structure. However, current methods for preparing hierarchically porous materials often employ dual surfactants or operate under harsh conditions, resulting in complex reaction steps. Furthermore, the pore structure formation mechanism of these porous materials remains unclear, and the influence of reaction conditions on pore structure remains to be elucidated (J. Am. Chem. Soc., 2023, 145, 5310–5319). Furthermore, polyphenols are ubiquitous in nature, with over 8,000 identified to date. Due to their abundant reactive functional groups, they can oxidatively self-polymerize to form cross-linked oligomers, which then form colloidal particles through weak intermolecular interactions such as π-π stacking, hydrogen bonding, and electrostatic interactions. Different types of polyphenols, due to their varying reactive sites, exhibit distinct reaction mechanisms and pore structures in the resulting porous materials. This makes the construction of porous materials based on polyphenols in a single micelle system extremely challenging. Summary of the Invention

[0004] In view of this, the present application provides a meso-macroporous material based on single micelle amine-induced self-assembly prepared by a single surfactant.

[0005] The present application also provides a method for preparing meso-macroporous materials based on single micelle amine-induced self-assembly, in which a single surfactant is used to prepare nanospheres with multi-level pores.

[0006] The present application also provides an application of a meso-macroporous material based on single micelle amine-induced self-assembly.

[0007] A meso-macroporous material based on single micelle amine-induced self-assembly is synthesized by self-assembly in a single micelle system composed of P123, 1,2,4-benzenetriol as a precursor, ethylenediamine as an initiator, and 1,3,5-trimethylbenzene as a pore expander, and then carbonized at high temperature to obtain nanospheres with multi-level channels of mesopores and macropores.

[0008] A method for preparing a meso-macroporous material based on single micellar amine-induced self-assembly comprises the following steps: Step S1: preparing nitrogen-doped multi-level pore nanospheres (NPS), which includes the following steps: Step S11: 100-300 mg of P123 was dissolved in 2-6 mL of deionized water by ultrasonication to form a single micelle system; Step S12: adding the single micelle system to 14-18 mL of ethanol solution; Step S13: Continue adding 110-150 mg of 1,2,4-benzenetriol, and after it is fully dissolved, add 600-1000 µL of 1,3,5-trimethylbenzene, and then dropwise add 30-40 µL of ethylenediamine. React at 600-1000 rpm for 4-6 hours until the reaction is complete; Step S14: washing with anhydrous ethanol and deionized water for 3 to 5 times respectively, and drying to obtain NPS; Step S2: preparing carbon nitride doped hierarchical pore nanospheres (CNPS), comprising the following steps: Step S21: heating the NPS to 150-200°C at a heating rate of 1°C / min and maintaining the temperature for 1-2 hours; Step S22: Continue heating to 300-400°C at a heating rate of 1°C / min and maintain for 1-2 hours; Step S23: Continue heating at a rate of 1°C / min to 700-800°C, maintain for 1-2 hours, and then cool to room temperature; Step S24: The obtained product is washed with deionized water for 3 to 5 times to finally obtain CNPS.

[0009] Application of a meso-macroporous material based on single micellar amine-induced self-assembly as an electrode material in oxygen reduction reaction.

[0010] Application of meso-macroporous materials based on single micellar amine-induced self-assembly in catalysts.

[0011] The technical effect of this application is that it uses a single surfactant, namely P123, as a single micelle system, 1,2,4-benzenetriol as a precursor, ethylenediamine as an initiator, and 1,3,5-trimethylbenzene as a pore-enlarging agent to prepare meso-macroporous materials, namely carbonized nitrogen-doped nanospheres with multi-level pores. Using a single surfactant, multi-level pores with both mesopores and macropores can be prepared.

[0012] At the same time, the 1,2,4-benzenetriol used in this application as a precursor has strong activity and is not easy to polymerize into porous materials. However, this application can prepare nanospheres with multi-level channels of mesopores and macropores by coordinating with P123 and setting strict reaction conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1The synthetic route of CNPS in this application; Figure 2 SEM images and TEM images of NPS of this application; Figure 3 SEM images and TEM images of CNPS of this application; Figure 4 HRTEM and EDX images of CNPS in this application; Figure 5 Schematic diagram of porous materials formed under the action of different single surfactants in this application; Figure 6 CV curves and LSV curves of the CNPS of this application in 0.1 mol / L KOH solution saturated with N2 or O2; Figure 7 (a) Time-current curves of CNPS-30 and Pt / C in the examples, and (b) time-current curves after adding methanol for about 900 s; In the figure: CNPS-0 represents the carbon nitride-doped porous spheres obtained from the ethanol solution with a content of 0% in step S12; CNPS-10 represents the carbon nitride-doped porous spheres obtained from the ethanol solution with a content of 10% in step S12, and so on. DETAILED DESCRIPTION

[0014] The following embodiments of the technical solution of the present application will be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present application and are therefore only examples and are not intended to limit the scope of protection of the present application.

[0015] A meso-macroporous material based on single micellar amine-induced self-assembly is prepared in a single micellar system composed of P123, with 1,2,4-benzenetriol as a precursor, ethylenediamine as an initiator, and 1,3,5-trimethylbenzene as a pore expander. Under different hydrogen bonding forces, the amino groups in ethylenediamine and the hydroxyl groups in 1,2,4-benzenetriol react to form self-assembled nanospheres with mesopores and macropores through high-temperature carbonization.

[0016] In a preferred embodiment, the particle size of the nanospheres is 290-350 nm, the mesopore size is 12-50 nm, and the macropore size is 50-130 nm.

[0017] A method for preparing a meso-macroporous material based on single micellar amine-induced self-assembly comprises the following steps: Step S1: preparing nitrogen-doped multi-level pore nanospheres (NPS), which includes the following steps: Step S11: 100-300 mg of P123 was dissolved in 2-6 mL of deionized water by ultrasonication to form a single micelle system; Step S12: Add the single-micelle system to 14-18 mL of an ethanol solution; Step S13: Continue to add 110-150 mg of 1,2,4-benzene triol, fully dissolve, then add 600-1000 µL of 1,3,5-trimethylbenzene, then drop 30-40 µL of ethylenediamine, and react for 4-6 h at 600-1000 rpm until the reaction is complete; Step S14: Wash with anhydrous ethanol and deionized water for 3-5 times, and dry to obtain NPS. Step S2: Carbon nitride-doped multi-level porous nanospheres (CNPS), comprising the following steps: Step S21: First heat the NPS to 150-200°C at a heating rate of 1°C / min, and maintain for 1-2 h; Step S22: Continue to heat to 300-400°C at a heating rate of 1°C / min, and maintain for 1-2 h; Step S23: Continue to heat to 700-800°C at a heating rate of 1°C / min, and maintain for 1-2 h, and then reduce to room temperature; Step S24: Wash the obtained product with deionized water for 3-5 times to finally obtain CNPS.

[0018] Further, the present application also finds that different concentrations of ethanol solution in step S12 have an important influence on the formation of the final multi-level pores. As the ethanol content increases, the pore size of the nanospheres also gradually increases. When the ethanol content is 30%, better meso-macroporous multi-level pores can be formed. The present application is relatively strict on the ethanol content, otherwise single-level pores will be obtained. The volume content of ethanol can fluctuate within 5%, i.e. 25%-35%. The following will be illustrated in combination with specific examples.

[0019] Example One Preparation of multi-level pores (meso-macroporous) CNPS: Preparation of nitrogen-doped porous spheres (NPS): First, 200 mg of P123 is ultrasonically dissolved in 4 mL of deionized water to form a single-micelle system, then the micelles are transferred to a round-bottom flask containing 6 mL of ethanol and 10 mL of deionized water (the volume content of ethanol is 30%), then 130 mg of 1,2,4-benzene triol is added, fully dissolved, then 800 µL of 1,3,5-trimethylbenzene is added, then 35 µL of ethylenediamine is slowly dropped, and the reaction is carried out at 800 rpm for 4 h. After the reaction is completed, wash with anhydrous ethanol and deionized water for 3-5 times, and dry to obtain NPS.

[0020] Preparation of carbon nitride-doped porous spheres (CNPS): The NPS was first heated to 200°C at a rate of 1°C / min and held for 1 hour. The temperature was then increased to 350°C at a rate of 1°C / min and held for 2 hours. Finally, the temperature was increased to 800°C at a rate of 1°C / min and held for 1 hour. After cooling to room temperature, the resulting product was washed repeatedly 3-5 times to obtain CNPS. Based on the amount of ethanol added, this product was named CNPS-30.

[0021] Example 2 This example is essentially the same as Example 1, except that the amounts of ethanol and water in the round-bottom flask were 0 mL ethanol and 16 mL deionized water, 2 mL ethanol and 14 mL deionized water, 4 mL ethanol and 12 mL deionized water, and 8 mL ethanol and 8 mL deionized water, respectively. The ethanol content in these flasks was 0%, 10%, 20%, and 40%, respectively. The resulting carbon nitride-doped porous spheres were named CNPS-0, CNPS-10, CNPS-20, and CNPS-40.

[0022] Figure 1 This is the synthesis route of the CNPS described in Examples 1 and 2. Specifically, in a single micelle system composed of P123, 1,2,4-benzenetriol is used as a precursor, ethylenediamine is used as an initiator, and 1,3,5-trimethylbenzene is used as a pore-expanding agent. The amino groups in ethylenediamine react with the hydroxyl groups in 1,2,4-benzenetriol to self-assemble and synthesize NPS. The resulting NPS is then subjected to high-temperature carbonization to obtain CNPS. Depending on the ethanol content in step S12, the resulting porous materials are CNPS-0, CNPS-10, CNPS-20, CNPS-30, and CNPS-40, respectively, where CNPS-0 indicates an ethanol content of 0, CNPS-10 indicates an ethanol content of 10%, and so on.

[0023] like Figure 2 As shown in the figure, the particle size of the prepared NPS ranges from 290 to 350 nm. As the ethanol content increases from low to high (0% to 40%), the pore size of the resulting NPS gradually increases. At 0% ethanol, the pores of NPS-0 are a single mesoporous structure distributed on the particle surface. At 10% ethanol, the pores of NPS-10 extend deep into the particle interior. At 20% ethanol, the pores of NPS-20 increase further and deepen within the particle interior. In particular, at 30% ethanol, NPS-30 exhibits a hierarchical pore structure with meso-macropores (mesopores: 35 nm, macropores: 62 / 130 nm). Further increasing the ethanol content results in NPS-40, which has an irregular structure.

[0024] This application takes CNPS-30 as an example to further verify the performance of CNPS. Figure 3 As shown, Figure 2A comparison revealed that the structure of the nanospheres remained unchanged before and after carbonization. The basic framework of the porous material remained intact after carbonization, a crucial prerequisite for subsequent applications.

[0025] like Figure 4 As shown, CNPs maintain the basic framework of porous carbon materials.

[0026] According to the above results, when the ethanol content is 30%, the prepared nanospheres have better multi-level pores and can be used as application materials after carbonization.

[0027] The present invention uses P123 single surfactant to prepare meso-macroporous hierarchical materials, but it is possible to replace it with other single surfactants commonly used in the art, such as F68, F127, F108, etc. Figure 5 As shown, the effect of the present application cannot be achieved. When F68 is used as the single surfactant of the present application, what is formed is an aggregate with irregular structure, and no mesopores or macropores are formed on the surface. When F127 or F108 is used as the single surfactant of the present application, the surface of the formed nanospheres are all mesopores. Even if the ethanol concentration is changed, the structural effect on the nanospheres is also relatively small. This shows that it is difficult to prepare meso-macroporous multi-level porous materials with a single surfactant during implementation.

[0028] The meso-macroporous material based on single micelle amine-induced self-assembly of the present application can be used as an electrode material in oxygen reduction reaction. Example 3 is an electrochemical test conducted by the present application.

[0029] Example 3 In a three-electrode system, Ag / AgCl (saturated with KCl) served as the reference electrode, a platinum wire served as the auxiliary electrode, and a catalyst-coated glassy carbon (GC, 3.0 mm diameter) electrode served as the working electrode. Specifically, the working electrode was prepared by ultrasonically dispersing 2 mg of CNPS in a mixture of ethanol (400 μL) and Nafion (5 wt.%, 20 μL) for 1 h. Then, 15 μL of the well-dispersed mixture was dropped onto the GC and allowed to dry completely at room temperature. ORR was measured using cyclic voltammetry (CV) and linear sweep voltammetry (LSV) at scan rates of 50 mV / s and 5 mV / s, respectively. All electrochemical tests were performed in 0.1 mol / L KOH saturated with N₂ or O₂ at room temperature.

[0030] like Figure 6As shown in Figure a, no obvious oxygen reduction reaction (ORR) characteristic peak was observed for CNPS-30 in N2-saturated electrolyte. In contrast, in O2-saturated electrolyte, a clear ORR characteristic peak appeared at 0.74 V, indicating that the material has ORR potential and can be used as an electrode material for oxygen reduction reaction. CNPS-30 shows an onset potential (V) comparable to that of commercial Pt / C catalysts and a higher limiting current density (J=5.8mA / cm), which may be related to its special pore structure (meso-macroporous) ( Figure 6 b).

[0031] The meso-macroporous material based on single micelle amine-induced self-assembly of the present application can also be used as a catalyst. Electrochemical stability and methanol resistance are important indicators for evaluating the practical application of catalysts. Figure 7 As shown in Figure a, after 60,000 s of stability testing, CNPS-30 still maintained 93.3% of its original activity. However, the relative current of Pt / C decreased to 78.4%, indicating that the CNPS catalyst has long-term stability compared to Pt / C. After adding methanol for 900 s, the relative current of Pt / C fluctuated significantly ( Figure 7 b). However, CNPS still maintains excellent stability, indicating that CNPS has better methanol tolerance than Pt / C.

[0032] The above results indicate that the meso-macroporous material based on single micelle amine-induced self-assembly of the present application can be used as a catalyst.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A meso-macroporous material based on single micellar amine-induced self-assembly, characterized by: The nanospheres are self-assembled and synthesized in a single micelle system composed of P123, with 1,2,4-benzenetriol as a precursor, ethylenediamine as an initiator, and 1,3,5-trimethylbenzene as a pore expander, and then carbonized at high temperature to obtain multi-level pores with mesopores and macropores.

2. The meso-macroporous material based on single micelle amine-induced self-assembly according to claim 1, characterized in that The particle size of the nanospheres is 290-350 nm, the mesopore size is 12-50 nm, and the macropore size is 50-130 nm.

3. A method for preparing meso-macroporous materials based on single micellar amine-induced self-assembly, characterized by: The following steps are involved: Step S1: preparing nitrogen-doped multi-level pore nanospheres (NPS), which includes the following steps: Step S11: 100-300 mg of P123 was dissolved in 2-6 mL of deionized water by ultrasonication to form a single micelle system; Step S12: adding the single micelle system to 14-18 mL of ethanol solution; Step S13: Continue adding 110-150 mg of 1,2,4-benzenetriol, and after it is fully dissolved, add 600-1000 µL of 1,3,5-trimethylbenzene, and then dropwise add 30-40 µL of ethylenediamine. React at 600-1000 rpm for 4-6 hours until the reaction is complete; Step S14: washing with anhydrous ethanol and deionized water for 3 to 5 times respectively, and drying to obtain NPS; Step S2: preparing carbon nitride doped hierarchical pore nanospheres (CNPS), comprising the following steps: Step S21: heating the NPS to 150-200°C at a heating rate of 1°C / min and maintaining the temperature for 1-2 hours; Step S22: Continue heating to 300-400°C at a heating rate of 1°C / min and maintain for 1-2 hours; Step S23: Continue heating at a rate of 1°C / min to 700-800°C, maintain for 1-2 hours, and then cool to room temperature; Step S24: The obtained product is washed with deionized water for 3 to 5 times to finally obtain CNPS.

4. The method for preparing a meso-macroporous material based on single micellar amine-induced self-assembly according to claim 3, characterized in that: In step S12, the volume content of ethanol in the ethanol solution is 25-35%.

5. The method for preparing a meso-macroporous material based on single micellar amine-induced self-assembly according to claim 3, characterized in that: In step S12, the volume content of ethanol in the ethanol solution is 30%.

6. Application of a meso-macroporous material based on single micellar amine-induced self-assembly as an electrode material in oxygen reduction reaction.

7. The use of the meso-macroporous material based on single micelle amine-induced self-assembly as an electrode material in an oxygen reduction reaction according to claim 6, characterized in that: Capable of performing cyclic voltammetry, linear sweep voltammetry, stability and methanol resistance determinations.

8. Application of a meso-macroporous material based on single micellar amine-induced self-assembly in catalysts.

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