A benzene sulfonic acid-ammonium hydrogen bond organic framework material and a preparation method and application thereof

Abstract

The application discloses a hydrogen-bonded organic framework material and a preparation method thereof, and the structural unit of the hydrogen-bonded organic framework material comprises a sulfonic acid group and an ammonium ion, the sulfonic acid group and the ammonium ion are connected to form a three-dimensional hydrogen-bonded network structure through charge-assisted hydrogen bonding, and the hydrogen-bonded organic framework material comprises at least one of 1,5-NDS_NH4 material, BPDS_NH4 material and MTBS_NH4 material; the chemical formula of the 1,5-NDS_NH4 material is [(C 10 H8O6S2)(NH4)2]n, the chemical formula of the BPDS_NH4 material is [(C 12 H8O6S2)(NH4)2]n, and the chemical formula of the MTBS_NH4 material is [(C 25 H 16 O 12 S4)(NH4)4]n, wherein n is a positive integer. The hydrogen-bonded organic framework material has excellent thermal stability and electrical conductivity.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of hydrogen-bonded organic framework materials, and particularly relates to a hydrogen-bonded organic framework material and a preparation method and application thereof. BACKGROUND

[0002] To cope with the two environmental crises of energy depletion and global warming, it is urgent to develop efficient and clean energy. Proton exchange membrane fuel cells (PEMFC) have attracted widespread attention due to their low emissions and high power density. The proton exchange membrane is an important component of PEMFC. The currently commercialized perfluorosulfonic acid Nafion membrane exhibits excellent proton conductivity under the condition of 85℃ and high humidity, but its excessive swelling, limited working temperature range and low fuel permeability hinder its large-scale popularization and application. In order to further improve the performance of PEMFC, it is urgent to develop proton conductive materials with high proton conductivity and high robustness.

[0003] Hydrogen-bonded organic frameworks (HOFs) as a new type of functional crystalline material, are attracting more and more attention in the field of proton conduction due to their self-assembly through non-covalent weak interactions, i.e. hydrogen bonds. These organic building blocks can accommodate protic solvent molecules (such as H2O, NH3, etc.) in their interstices or channels to form stable hydrogen bond networks during self-assembly. In these networks, the proton donor and acceptor functional groups together form an efficient proton transport path. Therefore, hydrogen-bonded organic framework materials have become a potential candidate platform for solid-state proton conductive materials due to their advantages of high proton conductivity, solution processability, reusability, and easy large-scale synthesis from inexpensive raw materials, and have shown broad application prospects in fuel cell technology. However, hydrogen bonds as a weak interaction force, the hydrogen-bonded organic framework materials connected by hydrogen bonds have poor stability, and the conductivity of hydrogen-bonded organic framework materials still needs to be improved. SUMMARY

[0004] The present application aims to at least partially solve at least one of the technical problems existing in the prior art. To this end, the present application provides a hydrogen-bonded organic framework material and a preparation method thereof, which has excellent thermal stability and conductivity.

[0005] Therefore, in the first aspect of the present application, a hydrogen-bonded organic framework material is provided. The structural unit of the hydrogen-bonded organic framework material comprises a sulfonic acid group and an ammonium ion, and the sulfonic acid group and the ammonium ion are connected to form a three-dimensional hydrogen bond network structure through charge-assisted hydrogen bonds. The hydrogen-bonded organic framework material comprises at least one of 1,5-NDS_NH4 material, BPDS_NH4 material and MTBS_NH4 material. The chemical formula of the 1,5-NDS_NH4 material is [(C 10H8O6S2)(NH4)2]n, the chemical formula of the BPDS_NH4 material is [(C 12 H8O6S2)(NH4)2]n, the chemical formula of the MTBS_NH4 material is [(C 25 H 16 O 12 S4)(NH4)4]n, wherein n is a positive integer.

[0006] In the hydrogen-bonded organic framework material of the present application, sulfonic acid groups and ammonium ions are connected into a three-dimensional supramolecular structure through charge-assisted hydrogen bonds, forming a continuous hydrogen bond chain. Thus, the thermal stability and electrical conductivity of the material are effectively improved.

[0007] In some embodiments, the 1,5-NDS_NH4 material satisfies at least one of the following:

[0008] (1) The structural unit of the 1,5-NDS_NH4 material belongs to a monoclinic system, the space group is P21 / c, and the molecular formula is C 10 H 16 N2O6S2, the unit cell parameters are: α = γ = 90°, β = 103.4°;

[0009] (2) The 1,5-NDS_NH4 material is polymerized from a plurality of repeating units, each repeating unit contains 1 1,5-NDS molecule and 2 ammonium ions, the 1,5-NDS is 1,5-naphthalene disulfonic acid; the sulfonic acid groups on the 1,5-NDS molecule and the ammonium ions are repeatedly polymerized to form a three-dimensional hydrogen bond network;

[0010] (3) The 1,5-NDS_NH4 material is thermally stable at a temperature of 320°C;

[0011] (4) The electrical conductivity of the 1,5-NDS_NH4 material under the conditions of 50-95% RH and 45-90°C is 5.6 x 10 -6 -6.6 x 10 -2 S / cm; wherein RH is relative humidity.

[0012] In some embodiments, the BPDS_NH4 material satisfies at least one of the following:

[0013] (a) The structural unit of the BPDS_NH4 material belongs to a monoclinic system, the space group is P21 / c, and the molecular formula is C 12 H 16 N2O6S2, the unit cell parameters are: α = γ = 90°, β = 96.7°;

[0014] (b) the BPDS_NH4 material is polymerized from a plurality of repeating units, each repeating unit comprising 1 BPDS molecule and 2 ammonium ions, the BPDS being 4,4'-biphenyl disulfonic acid; the sulfonic acid groups on the BPDS molecules are repeatedly polymerized with the ammonium ions to form a three-dimensional hydrogen-bonded network; the three-dimensional hydrogen-bonded network has a closed channel, and the porosity is 11%;

[0015] (c) the BPDS_NH4 material is thermally stable up to 200°C;

[0016] (d) the conductivity of the BPDS_NH4 material is 1.7 x 10 -5 ~ 2.1 x 10 -1 S / cm at 50-95% RH and 45-90°C; wherein RH is relative humidity.

[0017] In some embodiments, the MTBS_NH4 material satisfies at least one of the following:

[0018] (A) the structural unit of the MTBS_NH4 material belongs to the orthorhombic system, the space group is I4, the molecular formula is C 25 H 32 N4O 12 S4, and the unit cell parameters are: α = β = γ = 90°;

[0019] (B) the MTBS_NH4 material is polymerized from a plurality of repeating units, each repeating unit comprising 1 MTBS and 4 ammonium ions, the MTBS being tetrakis(4-sulfonatophenyl)methane; the sulfonic acid groups on the MTBS molecules are repeatedly polymerized with the ammonium ions to form a three-dimensional hydrogen-bonded network;

[0020] (C) the MTBS_NH4 material is thermally stable up to 160°C;

[0021] (D) the conductivity of the MTBS_NH4 material is 2.3 x 10 -6 ~ 4.6 x 10 -2 S / cm at 50-95% RH and 45-90°C; wherein RH is relative humidity.

[0022] In a second aspect of the present application, a preparation method of a hydrogen-bonded organic framework material is provided, comprising the following steps:

[0023] Mixing a sulfonic acid ligand, a solvent, and an ammonium source solution to perform a polymerization reaction to obtain a mixed solution;

[0024] Performing a crystallization treatment on the mixed solution to obtain a flaky crystal;

[0025] Removing the supernatant and naturally drying the flaky crystal to obtain a hydrogen-bonded organic framework material.

[0026] The application obtains a hydrogen-bonded organic framework material by adopting a crystallization method. The preparation process is simple, convenient to operate, and has high yield.

[0027] In some embodiments, the crystallization method comprises at least one of an evaporation crystallization method and a gas-phase diffusion crystallization method.

[0028] In some embodiments, the gas-phase diffusion crystallization method comprises a poor solvent, and the poor solvent comprises at least one of ethyl acetate and acetone.

[0029] In some embodiments, the preparation of the 1,5-NDS_NH4 material comprises at least one of the following:

[0030] (i) the sulfonic acid ligand comprises 1,5-NDS;

[0031] (ii) the solvent comprises N,N-dimethylformamide;

[0032] (iii) the ammonium source solution comprises an ammonium chloride solution with a molar concentration of 1 mol / L;

[0033] (iv) the molar ratio of 1,5-NDS to the ammonium chloride solution is 1:(2-4);

[0034] (v) the ratio of 1,5-NDS to the solvent is 8-15 mg / mL;

[0035] (vi) the crystallization method comprises a gas-phase diffusion crystallization method.

[0036] In some embodiments, the preparation of the BPDS_NH4 material comprises at least one of the following:

[0037] (I) the sulfonic acid ligand comprises BPDS;

[0038] (II) the solvent comprises methanol;

[0039] (III) the ammonium source solution comprises an ammonium chloride solution with a molar concentration of 1 mol / L;

[0040] (IV) the molar ratio of BPDS to the ammonium chloride solution is 1:(2-4);

[0041] (V) the ratio of BPDS to the solvent is 8-12 mg / mL.

[0042] In some embodiments, the preparation of the MTBS_NH4 material comprises at least one of the following:

[0043] (1) the sulfonic acid ligand comprises MTBS;

[0044] (2) the solvent comprises methanol;

[0045] (3) the ammonium source solution comprises a 1 mol / L ammonium chloride solution;

[0046] (4) the molar ratio of MTBS to the ammonium chloride solution is 1: (4-6) ;

[0047] (5) the ratio of MTBS to the solvent is 10-12 mg / mL;

[0048] (6) the crystallization method comprises a gas-phase diffusion crystallization method.

[0049] In a third aspect, the present application provides a proton exchange membrane comprising the hydrogen-bonded organic framework material of the first aspect, or, the hydrogen-bonded organic framework material obtained by the preparation method of the second aspect.

[0050] Thus, the proton exchange membrane of the present application has excellent thermal stability and proton conductivity.

[0051] In a fourth aspect, the present application provides a proton exchange membrane fuel cell comprising the proton exchange membrane of the third aspect.

[0052] Thus, the proton exchange membrane fuel cell of the present application has excellent thermal stability and proton conductivity.

[0053] Compared with the prior art, the present application has the following beneficial technical effects:

[0054] (1) The structural unit of the hydrogen-bonded organic framework material of the present application comprises a sulfonic acid group and an ammonium ion, and the four hydrogen atoms on the ammonium ion can be used to form hydrogen bonds, thereby increasing the number of hydrogen bonds and improving the stability of the hydrogen bond network structure. At the same time, the proton conduction capacity of the hydrogen-bonded organic framework material is effectively improved, and the electrical conductivity reaches 2.1 x 10 -1 S / cm under high temperature and high humidity conditions.

[0055] (2) The hydrogen-bonded organic framework material of the present application can be obtained by a gas-phase diffusion crystallization method and an evaporation crystallization method, and has simple preparation process, convenient operation and high yield.

[0056] Additional aspects and advantages of the present application will be partially given in the following description, partially will become obvious from the following description, or will be understood by the practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0057] The above and / or additional aspects and advantages of the present application will become apparent and be readily understood from the following description, taken in conjunction with the accompanying drawings, in which:

[0058] Figure 1 is a schematic diagram of the crystal structure of the 1,5-NDS_NH4 hydrogen-bonded organic framework material prepared in Example 1.

[0059] Figure 2 is a schematic diagram of the crystal structure of the BPDS_NH4 hydrogen-bonded organic framework material prepared in Example 2 and Example 3;

[0060] Figure 3 is a schematic diagram of the crystal structure of the MTBS_NH4 hydrogen-bonded organic framework material prepared in Example 4;

[0061] Figure 4 is a comparison of the XRD patterns of the hydrogen-bonded organic framework material crystal powders prepared in Example 1 (A), Example 2 (B) and Example 4 (C) with the simulated XRD patterns of their single crystal structures;

[0062] Figure 5 is a comparison of the thermogravimetric curve analysis of the hydrogen-bonded organic framework material crystal powders prepared in Example 1 (A), Example 2 (B) and Example 4 (C) with their original benzenesulfonic acid-based ligands;

[0063] Figure 6 is a comparison of the hydrogen-bonded organic framework material crystal powders prepared in Example 1 (A), Example 2 (B) and Example 4 (C) with the Eyring curves obtained in Example 5. DETAILED DESCRIPTION

[0064] Embodiments of the present application are described in detail below. The embodiments described below are examples for explaining the present application and should not be understood as limiting the present application.

[0065] It should be noted that the terms "first", "second" are used only for the purpose of description and should not be understood as indicating or implying relative importance or implying the number of the technical features indicated. Thus, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. Further, in the description of the present application, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0066] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The ranges or values should be construed to be roughly about the ranges or values. For ranges, the endpoints are included as well as intervening points which are included in the ranges. For values, the values are included as well as intervening values which are included in the values.

[0067] In this document, the term "comprising" or "including" is an open term, which means that it includes the indicated content but not excluding other content.

[0068] In a first aspect, the present application provides a hydrogen-bonded organic framework material, the structural unit of the hydrogen-bonded organic framework material comprising a sulfonic acid group and an ammonium ion, the sulfonic acid group and the ammonium ion being connected to form a three-dimensional hydrogen-bonded network structure through a charge-assisted hydrogen bond; the hydrogen-bonded organic framework material comprising at least one of 1,5-NDS_NH4 material, BPDS_NH4 material, and MTBS_NH4 material; the 1,5-NDS_NH4 material having a chemical formula of [(C 10 H 12 8O6S2)(NH4)2]n, the BPDS_NH4 material having a chemical formula of [(C 25 H 16 8O6S2)(NH4)2]n, and the MTBS_NH4 material having a chemical formula of [(C 12 H -1 8O6S2)(NH4)2]n, wherein n is a positive integer.

[0069] According to the embodiments of the present application, in the hydrogen-bonded organic framework material, the sulfonic acid group and the ammonium ion are connected to form a three-dimensional supramolecular structure through a charge-assisted hydrogen bond, thereby forming a continuous hydrogen-bonded chain. The hydrogen-bonded organic framework material in the prior art usually uses organic ligands to connect with each other to build a hydrogen-bonded motif. Compared with the hydrogen-bonded organic framework material, the present application introduces an inorganic molecule, i.e., the ammonium ion, which is much smaller in size than the organic building unit, so that the connection and adjustment of the hydrogen bond are more flexible and variable, and the four hydrogen atoms on the ammonium ion can be used to form hydrogen bonds, thereby increasing the number of hydrogen bonds and improving the stability of the hydrogen-bonded network structure. The present application uses three different sulfonic acid ligands to prepare three hydrogen-bonded organic framework materials under different synthesis conditions, which also reflects the universality of the ammonium ion as a node to adjust the sulfonic acid ligand in the hydrogen-bonded network structure. After the organic ligand forms the hydrogen-bonded network structure, the thermal stability is obviously improved. In addition, the anionic sulfonic acid group and the cationic ammonium ion can act as proton carriers to transport protons, thereby effectively improving the proton conduction capacity of the hydrogen-bonded organic framework material. Under high temperature and high humidity conditions, the conductivity is up to 2.1×10 -1 S / cm. Therefore, the hydrogen-bonded organic framework material has excellent thermal stability and conductivity.

[0070] In some embodiments of the present application, the 1,5-NDS_NH4 material satisfies at least one of the following:

[0071] (1) the structural unit of the 1,5-NDS_NH4 material belongs to a monoclinic system, the space group is P21 / c, and the molecular formula is C 10 H 16 N2O6S2; the unit cell parameters are: α = γ = 90°, β = 103.4°;

[0072] (2) The 1,5-NDS_NH4 material is polymerized by a plurality of repeating units, each of which contains one 1,5-NDS molecule and two ammonium ions, the 1,5-NDS being 1,5-naphthalene disulfonic acid; the sulfonic acid groups on the 1,5-NDS molecule are repeatedly polymerized with the ammonium ions to form a three-dimensional hydrogen bond network;

[0073] (3) The 1,5-NDS_NH4 material has a thermal stability temperature of 320℃;

[0074] (4) The conductivity of the 1,5-NDS_NH4 material under the conditions of 50-95% RH and 45-90℃ is 5.6×10 -6 ~ 6.6×10 -2 S / cm; wherein RH is relative humidity.

[0075] Therefore, the hydrogen-bonded organic framework material has excellent thermal stability and conductivity.

[0076] In some embodiments of the present application, the BPDS_NH4 material satisfies at least one of the following:

[0077] (a) The structural unit of the BPDS_NH4 material belongs to a monoclinic system, the space group is P21 / c, the molecular formula is C 12 H 16 N2O6S2, and the unit cell parameters are: α = γ = 90°, β = 96.7°;

[0078] (b) The BPDS_NH4 material is polymerized by a plurality of repeating units, each of which contains one BPDS molecule and two ammonium ions, the BPDS being 4,4'-biphenyl disulfonic acid; the sulfonic acid groups on the BPDS molecule are repeatedly polymerized with the ammonium ions to form a three-dimensional hydrogen bond network; the three-dimensional hydrogen bond network has a closed channel, and the porosity is 11%;

[0079] (c) The BPDS_NH4 material has a thermal stability temperature of 200℃;

[0080] (d) The conductivity of the BPDS_NH4 material under the conditions of 50-95% RH and 45-90℃ is 1.7×10 -5 ~ 2.1×10 -1 S / cm; wherein RH is relative humidity.

[0081] Therefore, the hydrogen-bonded organic framework material has excellent thermal stability and conductivity.

[0082] In some embodiments of the present application, the MTBS_NH4 material satisfies at least one of the following:

[0083] (A) The structural unit of the MTBS_NH4 material belongs to the orthorhombic system, the space group is I4, the molecular formula is C 25 H 32 N4O 12 S4, the cell parameters are: α=β=γ=90°;

[0084] (B) The MTBS_NH4 material is polymerized by a plurality of repeating units, each of which contains 1 MTBS and 4 ammonium ions, the MTBS is tetra(4-sulfonic phenyl) methane; the sulfonic acid groups on the MTBS molecules are repeatedly polymerized with the ammonium ions to form a three-dimensional hydrogen bond network;

[0085] (C) The MTBS_NH4 material is thermally stable at a temperature of 160℃;

[0086] (D) The conductivity of the MTBS_NH4 material is 2.3×10 -6 ~4.6×10 -2 S / cm under the conditions of 50~95% RH and 45~90℃; wherein, RH is relative humidity.

[0087] Therefore, the hydrogen-bonded organic framework material has excellent thermal stability and conductivity.

[0088] In a second aspect of the embodiments of the present application, a preparation method of the hydrogen-bonded organic framework material is provided, comprising the following steps:

[0089] Mixing the sulfonic acid ligand, the solvent and the ammonium source solution to perform a polymerization reaction to obtain a mixed solution;

[0090] Performing a crystallization treatment on the mixed solution to obtain a flaky crystal;

[0091] Removing the supernatant and naturally drying the flaky crystal to obtain the hydrogen-bonded organic framework material.

[0092] According to the embodiments of the present application, the hydrogen-bonded organic framework material is obtained by the method of crystallization treatment. The preparation process is simple, the operation is convenient, and the yield is high.

[0093] In some embodiments of the present application, the method of crystallization treatment comprises at least one of an evaporation crystallization method and a gas phase diffusion crystallization method.

[0094] In some embodiments of the present application, the gas phase diffusion crystallization method comprises a poor solvent, and the poor solvent comprises at least one of ethyl acetate and acetone.

[0095] According to the embodiments of the present application, the poor solvent enters the solute solution in the (good) solvent through gas-phase diffusion, so that the solubility of the solute is reduced, and when the solubility of the solute is reduced to below the saturation point, the solute begins to crystallize, thereby obtaining sheet-shaped crystals. Thus, a hydrogen-bonded organic framework material can be obtained.

[0096] In some embodiments of the present application, the preparation of the 1,5-NDS_NH4 material comprises at least one of the following:

[0097] (i) the sulfonic acid ligand comprises 1,5-NDS;

[0098] (ii) the solvent comprises N,N-dimethylformamide;

[0099] (iii) the ammonium source solution comprises an ammonium chloride solution with a molar concentration of 1 mol / L;

[0100] (iv) the molar ratio of 1,5-NDS to the ammonium chloride solution is 1:(2-4);

[0101] (v) the ratio of 1,5-NDS to the solvent is 8-15 mg / mL;

[0102] (vi) the method of the crystallization treatment comprises a gas-phase diffusion crystallization method.

[0103] Thus, the 1,5-NDS_NH4 material prepared by the present application has excellent thermal stability and conductivity.

[0104] In some embodiments of the present application, the preparation of the BPDS_NH4 material comprises at least one of the following:

[0105] (I) the sulfonic acid ligand comprises BPDS;

[0106] (II) the solvent comprises methanol;

[0107] (III) the ammonium source solution comprises an ammonium chloride solution with a molar concentration of 1 mol / L;

[0108] (IV) the molar ratio of BPDS to the ammonium chloride solution is 1:(2-4);

[0109] (V) the ratio of BPDS to the solvent is 8-12 mg / mL.

[0110] Thus, the BPDS_NH4 material prepared by the present application has excellent thermal stability and conductivity.

[0111] In some embodiments of the present application, the preparation of the MTBS_NH4 material comprises at least one of the following:

[0112] (1) the sulfonic acid ligand comprises MTBS;

[0113] (2) the solvent comprises methanol;

[0114] (3) the ammonium source solution comprises a 1 mol / L ammonium chloride solution;

[0115] (4) the molar ratio of the MTBS to the ammonium chloride solution is 1: (4-6) ;

[0116] (5) the ratio of the MTBS to the solvent is 10-12 mg / mL;

[0117] (6) the crystallization method comprises a vapor-phase diffusion crystallization method.

[0118] Thus, the MTBS_NH4 material prepared by the application has excellent thermal stability and conductivity.

[0119] In a third aspect of the embodiments of the application, the application provides a proton exchange membrane comprising the hydrogen-bonded organic framework material of the first aspect, or, a hydrogen-bonded organic framework material prepared by the preparation method of the second aspect.

[0120] Thus, the proton exchange membrane of the application has excellent thermal stability and proton conductivity.

[0121] In a third aspect of the embodiments of the application, the application provides a proton exchange membrane fuel cell comprising the proton exchange membrane of the third aspect.

[0122] Thus, the proton exchange membrane fuel cell of the application has excellent thermal stability and proton conductivity.

[0123] The schemes of the application will be explained below in combination with the embodiments. Those skilled in the art will understand that the following embodiments are only used to illustrate the application, and should not be regarded as limiting the scope of the application. If the specific techniques or conditions are not specified in the embodiments, the techniques or conditions described in the literature in the art or according to the product instructions are used. If the reagents or instruments are not specified by the manufacturer, they are all conventional products that can be obtained by purchase.

[0124] Example 1: Preparation of 1,5-NDS_NH4 hydrogen-bonded organic framework material by a vapor-phase diffusion crystallization method

[0125] (1) 50 mg of 1,5-NDS was dissolved in 5 mL of N,N-dimethylformamide solution, and then 100 μL of a 1 mol / L ammonium chloride solution was added to the solution, which was ultrasonically dissolved and then filtered by using a 0.45 μm nylon filter to obtain a mixed solution;

[0126] (2) The mixed solution was placed in a 10 mL sample bottle, and the sample bottle was placed open in a 50 mL wide-mouth bottle containing 10 mL ethyl acetate, the bottle cap was tightened, and it was placed in a room temperature environment. After 4 days of reaction, colorless transparent flaky crystals were obtained;

[0127] (3) The supernatant was removed, and the flaky crystals were naturally dried to obtain 1,5-NDS_NH4 hydrogen-bonded organic framework material.

[0128] It was determined that the yield of 1,5-NDS_NH4 hydrogen-bonded organic framework material was 58% (calculated based on the mass of 1,5-NDS). Its structure was determined by a single crystal X-ray diffractometer, and the cell parameters were α = γ = 90°, β = 103.4°, Figure 1 is a schematic diagram of the crystal structure of 1,5-NDS_NH4 hydrogen-bonded organic framework material.

[0129] As shown in Figure 1 , the ammonium ion in 1,5-NDS_NH4 forms a hydrogen bond of N-H…O with the oxygen atom on the sulfonic acid group, and a continuous hydrogen bond chain is repeatedly formed. The asymmetric unit of 1,5-NDS_NH4 material is composed of one deprotonated 1,5-NDS and two ammonium ions (NH4 + ). The protonated NH4 + and the deprotonated sulfonate are combined together through charge-assisted hydrogen bonding, which can improve the stability of the hydrogen-bonded organic framework, and the π-π stacking interaction force between the layers also improves the stability of the hydrogen-bonded organic framework.

[0130] Example 2: Preparation of BPDS_NH4 hydrogen-bonded organic framework material by evaporation crystallization method

[0131] (1) 50 mg of BPDS was dissolved in 5 mL of methanol solution, and then 100 μL of 1 mol / L ammonium chloride solution was added to the solution. After ultrasonic dissolution, a 0.45 μm nylon filter was used for filtration to obtain a mixed solution;

[0132] (2) The mixed solution was placed in a 10 mL sample bottle, and the sample bottle was placed open in a 50 mL wide-mouth bottle containing 10 mL ethyl acetate, the bottle cap was tightened, and it was placed in a room temperature environment. After 4 days of reaction, colorless transparent flaky crystals were obtained;

[0133] (3) The supernatant was removed, and the flaky crystals were naturally dried to obtain BPDS_NH4 hydrogen-bonded organic framework material.

[0134] It was determined that the yield of BPDS_NH4 hydrogen-bonded organic framework material was 54.5% (calculated based on the mass of BPDS). Its structure was determined by a single crystal X-ray diffractometer, and the cell parameters were α = γ = 90°, β = 96.7°, Figure 2 A schematic diagram of the crystal structure of the BPDS_NH4 hydrogen-bonded organic framework material.

[0135] Example 3: Preparation of BPDS_NH4 hydrogen-bonded organic framework material by vapor diffusion crystallization method

[0136] (1) 50 mg of BPDS was dissolved in 5 mL of methanol solution, and then 100 μL of 1 mol / L ammonium chloride solution was added to the solution. After ultrasonic dissolution, the solution was filtered using a 0.45 μm nylon filter to obtain a mixed solution;

[0137] (2) The mixed solution was placed in a 10 mL sample bottle, and the sample bottle was placed in a 50 mL wide-mouth bottle containing 10 mL of acetone with the opening exposed. The bottle cap was tightened and placed in a room temperature environment. After 7 days of reaction, colorless transparent sheet-shaped crystals were obtained;

[0138] (3) The supernatant was removed, and the sheet-shaped crystals were naturally dried to obtain the BPDS_NH4 hydrogen-bonded organic framework material.

[0139] After measurement, the yield of the BPDS_NH4 hydrogen-bonded organic framework material was 35.8% (calculated based on the mass of BPDS). Its structure was determined using a single crystal X-ray diffractometer, and the cell parameters were as follows: α = γ = 90°, β = 96.7°, Figure 2 A schematic diagram of the crystal structure of the BPDS_NH4 hydrogen-bonded organic framework material.

[0140] As shown in Figure 2 , the ammonium ions in BPDS_NH4 form N-H…O hydrogen bonds with the oxygen atoms on the sulfonic acid groups, and continuous hydrogen bond chains are repeatedly formed. The asymmetric unit of BPDS_NH4 is composed of one deprotonated BPDS and two ammonium ions (NH4 + ). The protonated NH4 + and the deprotonated sulfonate are combined together through charge-assisted hydrogen bonds, which is beneficial to enhance the stability of the hydrogen-bonded organic framework. The BPDS molecules between the layers are arranged in different orientations, forming a closed channel structure with a porosity of 11%.

[0141] Example 4: Preparation of MTBS_NH4 hydrogen-bonded organic framework material by vapor diffusion crystallization method

[0142] (1) 50 mg of MTBS was dissolved in 5 mL of methanol solution, and then 100 μL of 1 mol / L ammonium chloride solution was added to the solution. After ultrasonic dissolution, the solution was filtered using a 0.45 μm nylon filter to obtain a mixed solution;

[0143] (2) Place the mixture in a 10 mL sample bottle, place the sample bottle open in a 50 mL wide-mouth bottle with a cap containing 10 mL of ethyl acetate, tighten the cap, and place it at room temperature. After reacting for 4 days, colorless and transparent flaky crystals are obtained.

[0144] (3) Remove the supernatant and let the sheet-like crystals dry naturally to obtain MTBS_NH4 hydrogen-bonded organic framework material.

[0145] The yield of MTBS_NH4 hydrogen-bonded organic framework material was determined to be 38% (based on the mass of MTBS). Its structure and unit cell parameters were determined using single-crystal X-ray diffraction. α=β=γ=90°, Figure 3 This is a schematic diagram of the crystal structure of MTBS_NH4 hydrogen-bonded organic framework material.

[0146] like Figure 3 As shown, in MTBS_NH4, the ammonium ion forms an NH…O hydrogen bond with the oxygen atom on the sulfonic acid group, and this process repeats to form a continuous hydrogen bond chain. The asymmetric unit of MTBS_NH4 consists of a deprotonated MTBS and four ammonium ions (NH4+). + Composition: Protonated NH4 + The deprotonated sulfonate group is bound to the hydrogen-bonded organic framework through charge-assisted hydrogen bonds, which can enhance the stability of the hydrogen-bonded organic framework. At the same time, the π-π stacking interaction between layers also enhances the stability of the hydrogen-bonded organic framework.

[0147] like Figure 4 As shown, the X-ray diffraction data simulated by the powder samples of the three materials 1,5-NDS_NH4, BPDS_NH4 and MTBS_NH4 prepared and the single crystal data are compared. The peaks of the three hydrogen-bonded organic framework materials obtained are consistent with the simulated diffraction data, indicating that the hydrogen-bonded organic framework materials prepared by the method of the present invention have high purity and still maintain stable crystal structure after drying.

[0148] like Figure 5 As shown, the thermogravimetric analysis (TGA) curves of the three prepared materials, 1,5-NDS_NH4, BPDS_NH4, and MTBS_NH4, compared with those of the organic ligands (1,5-NDS, BPDS, and MTBS), indicate that the formation of hydrogen bonds effectively improves the thermal stability of the materials. The TGA curves of the original ligands all show significant weight loss at 100℃, but after forming a hydrogen bond network with ammonium ions, the weight loss of 1,5-NDS_NH4 only begins at 320℃, while BPDS_NH4 shows weight loss at 200℃, and MTBS_NH4 shows weight loss at 160℃.

[0149] Example 5: Proton conductivity test of three hydrogen-bonded organic framework materials

[0150] (1) The hydrogen-bonded organic framework materials obtained in Example 1, Example 2 and Example 4 were ground into powders, 90 mg of the powder sample was loaded into an 8 mm tablet press mold, and after applying a pressure of 7 MPa by a tablet press, the sample pressed into a sheet shape was taken out of the mold, the thickness of each sample was 0.18 mm, and the area was 0.5024 cm 2 .

[0151] (2) The sheet-shaped sample was loaded into the mold, the sample was fixed using the metal rods at both ends of the mold, and the mold was placed in a constant temperature and humidity chamber, and an electrochemical workstation was connected. The temperature and humidity were adjusted using the constant temperature and humidity chamber, and the relative humidity was controlled to be stable at 95%, and the temperature was adjusted from 45℃ to 90℃. After waiting for 15 minutes for the constant temperature and humidity chamber to stabilize each time the temperature was adjusted, the electrical conductivity of the sample was tested using the electrochemical workstation.

[0152] (3) After the test, the resistance value Rs was obtained by fitting the Nyquist curve, and the electrical conductivity of the hydrogen-bonded organic framework materials obtained in Example 1, Example 2 and Example 4 was calculated by the formula . In the formula, σ is the electrical conductivity, the unit is S / cm; Rs is the resistance value, the unit is Ω; L is the thickness of the sample, the unit is cm; S is the area of the sample, the unit is cm 2 .

[0153] As Figure 6 shown, the electrical conductivity of the 1,5-NDS_NH4 material of the application reached 6.6 x 10 -2 S / cm at 90℃ and 95% RH, the electrical conductivity of the BPDS_NH4 material of the application reached 2.1 x 10 -1 S / cm at 90℃ and 95% RH, and the electrical conductivity of the MTBS_NH4 material of the application reached 4.6 x 10 -2 S / cm at 90℃ and 95% RH.

[0154] The results show that the hydrogen-bonded organic framework material of the application has excellent thermal stability and electrical conductivity, and when applied to a proton exchange membrane fuel cell, the thermal stability and electrical conductivity of the fuel cell can be effectively improved.

[0155] In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0156] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A method of preparing a hydrogen-bonded organic framework material, characterized by, The method comprises the following steps: mixing a sulfonic acid ligand, a solvent and an ammonium source solution to perform a polymerization reaction to obtain a mixed solution; performing a crystallization treatment on the mixed solution to obtain a flaky crystal; remove the supernatant, and naturally dry the sheet-shaped crystals to obtain a hydrogen-bonded organic framework material, a structural unit of the hydrogen-bonded organic framework material comprising sulfonic acid groups and ammonium ions, the sulfonic acid groups and the ammonium ions being connected by charge-assisted hydrogen bonds to form a three-dimensional hydrogen-bonded network structure; the hydrogen-bonded organic framework material comprising at least one of 1,5-NDS_NH4 material and MTBS_NH4 material; the 1,5-NDS_NH4 material having a chemical formula of [(C 10 H8O6S2)(NH4)2]n, and the MTBS_NH4 material having a chemical formula of [(C 25 H 16 O 12 S4)(NH4)4]n, n being a positive integer, wherein, Preparation of the 1,5-NDS NH4 material comprises the following conditions: (i) the sulfonic acid ligand comprises 1,5-NDS; (ii) the solvent comprises N,N-dimethylformamide; (iii) the ammonium source solution comprises an ammonium chloride solution with a molar concentration of 1 mol / L; (iv) the molar ratio of the 1,5-NDS to the ammonium chloride solution is 1: (2-4); (v) the ratio of the 1,5-NDS to the solvent is 8-15 mg / mL; (vi) the method of the crystallization treatment comprises a vapor phase diffusion crystallization method; Preparation of the MTBS NH4 material comprises the following conditions: (1) the sulfonic acid ligand comprises MTBS; (2) the solvent comprises methanol; (3) the ammonium source solution comprises an ammonium chloride solution with a molar concentration of 1 mol / L; (4) the molar ratio of the MTBS to the ammonium chloride solution is 1: (4-6); (5) the ratio of the MTBS to the solvent is 10-12 mg / mL; (6) the method of the crystallization treatment comprises a vapor phase diffusion crystallization method.

2. The production method according to claim 1, characterized by, The vapor phase diffusion crystallization method comprises a poor solvent, and the poor solvent comprises at least one of ethyl acetate and acetone.

3. The hydrogen-bonded organic framework material produced by the method of claim 1 or 2, characterized by, The structural unit of the hydrogen-bonded organic framework material comprises sulfonic acid groups and ammonium ions, the sulfonic acid groups and the ammonium ions are connected by charge-assisted hydrogen bonds to form a three-dimensional hydrogen-bonded network structure; the hydrogen-bonded organic framework material comprises at least one of 1,5-NDS_NH4 material and MTBS_NH4 material; the chemical formula of the 1,5-NDS_NH4 material is [(C 10 H8O6S2)(NH4)2]n, and the chemical formula of the MTBS_NH4 material is [(C 25 H 16 O 12 S4)(NH4)4]n, n is a positive integer, wherein, The 1,5-NDS_NH4 material satisfies the following conditions: (1) a structural unit of the 1,5-NDS_NH4 material belongs to a monoclinic system, and a space group is P21 / c , a molecular formula is C 10 H 16 N2O6S2, and a unit cell parameter is: a = 11.38 Å, b = 7.34 Å, c = 7.99 Å, α = γ = 90°, β = 103.4°; (2) the 1,5-NDS_NH4 material is polymerized by a plurality of repeating units, each of which contains one 1,5-NDS molecule and two ammonium ions, the 1,5-NDS is 1,5-naphthalene disulfonic acid; sulfonic acid groups on the 1,5-NDS molecule and ammonium ions are repeatedly polymerized to form a three-dimensional hydrogen bond network; (3) the 1,5-NDS_NH4 material is thermally stable at a temperature of 320°C; (4) the 1,5-NDS_NH4 material has an electrical conductivity of 5.6 x 10 -6 ~ 6.6 x 10 -2 S / cm under conditions of 50~95% RH and 45~90°C; wherein RH is relative humidity. The MTBS_NH4 material satisfies the following conditions: (A) the structural unit of the MTBS_NH4 material belongs to an orthorhombic system, and the space group is Pnma I4 , the molecular formula is C 25 H 32 N4O 12 S4, and the cell parameters are: a = b = 14.69 Å, c = 7.23 Å, α = β=γ = 90°; (B) the MTBS_NH4 material is polymerized by a plurality of repeating units, each of which contains 1 MTBS and 4 ammonium ions, and the MTBS is tetra (4-sulfonic phenyl) methane; the sulfonic acid groups on the MTBS molecule are repeatedly polymerized with the ammonium ions to form a three-dimensional hydrogen bond network; (C) the MTBS_NH4 material is thermally stable at a temperature of 160°C; (D) the conductivity of the MTBS_NH4 material under the conditions of 50-95% RH and 45-90°C is 2.3×10 -6 ~4.6×10 -2 S / cm; wherein RH is relative humidity.

4. A proton exchange membrane, characterized by, The hydrogen-bonded organic framework material of claim 3, or the hydrogen-bonded organic framework material obtained by the preparation method of claim 1 or 2.

5. A proton exchange membrane fuel cell characterized by comprising: The proton exchange membrane of claim 4.

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