A two-dimensional electrocatalytic hydrogen evolution material based on cation-pi interaction, a preparation method and application thereof

Abstract

The application discloses a kind of two-dimensional electrocatalytic hydrogen evolution materials based on cation-π interaction construction and preparation method and application, specifically related to the field of catalyst, including multiple two-dimensional electrocatalytic hydrogen evolution monomers, multiple two-dimensional electrocatalytic hydrogen evolution monomers are connected head to tail between, the preparation method of monomer includes: 4,4'-dihydroxy azobenzene, bromoaromatic hydrocarbon, tetrabutylammonium iodide and cesium carbonate are coupled to obtain product;Product, 1,2-dibromoethane, cesium carbonate are etherified to obtain R2-bromoazobenzenyl compound;R2-bromoazobenzenyl compound, aromatic cation are subjected to nucleophilic substitution reaction, and ammonium hexafluorophosphate solution is added to carry out anion exchange reaction, to obtain R1-ethoxy-phenyl-azo-phenyloxy-ethyl-R2-hexafluorophosphate salt.Can significantly increase the exposure of hydrogen adsorption active site, thereby significantly improve the electrocatalytic hydrogen evolution performance.

Description

Technical Field

[0001] The present application relates to the field of catalysts, and in particular to a two-dimensional electrocatalytic hydrogen evolution material constructed based on cation-π interaction, and a preparation method and application thereof. Background Art

[0002] Electrocatalytic hydrogen evolution (EHE) is a key technology for the efficient production of hydrogen from water and is of great significance for sustainable energy conversion. Organic electrocatalysts are valued for their low cost and highly tunable structure, but they still face challenges in terms of activity and catalytic performance. To improve the performance of these catalysts, it is necessary to precisely control the electronic structure and active sites at the molecular level and enhance the precise control of material properties through synthetic strategies. Therefore, the development of new organic electrocatalytic hydrogen evolution materials with optimized performance and their preparation methods are crucial to promoting the commercialization of EHE technology. This will not only improve catalytic efficiency but also ensure the economic feasibility of the technology and the sustainability of its application.

[0003] Existing methods have achieved universal and customizable synthesis of multi-component systems through a pyrolysis-free strategy, constructing electrocatalysts containing active sites of both single atoms and platinum nanoclusters, which exhibit good catalytic hydrogen evolution performance under both acidic and alkaline conditions. However, this construction method generally requires the introduction of specific metal anchoring sites, which limits the diverse design of catalyst molecules. Moreover, additional metal doping groups may interfere with the orderly arrangement of catalyst molecules. These factors are detrimental to the stability of electrocatalytic materials and the expression and optimization of their functions, leading to poor catalytic performance.

[0004] Another method achieves the construction of a single-atom catalyst with efficient electrocatalytic hydrogen evolution performance by applying external light stimulation and introducing metal Pt atoms. However, this construction method not only requires the introduction of specific metal anchoring sites, but also relies on external light-responsive configuration transformation, thereby limiting the exposure to the electronic structure and active sites, resulting in poor catalytic performance. Summary of the Invention

[0005] The main purpose of this application is to provide a two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction and its preparation method and application, aiming to solve the problem of poor catalytic performance of existing catalysts.

[0006] To achieve the above objectives, the present application provides a two-dimensional electrocatalytic hydrogen evolution monomer, the structural formula of which is:

[0007]

[0008] Among them, R1 is a cationic unit, R1 is C5H5N or C4H6N, R2 is a π unit, R2 is C 10 H8 is C 12 H8N.

[0009] To achieve the above-mentioned objectives, the present application also provides a method for preparing the above-mentioned two-dimensional electrocatalytic hydrogen evolution monomer, comprising: dissolving 4,4'-dihydroxyazobenzene, a brominated aromatic hydrocarbon, tetrabutylammonium iodide and cesium carbonate in a first solvent for a coupling reaction to obtain (E)-4-((4-(2-X-ethoxy)phenyl)azo)phenol; dissolving (E)-4-((4-(2-X-ethoxy)phenyl)azo)phenol, 1,2-dibromoethane and cesium carbonate in a second solvent for an etherification reaction to obtain an R2-bromoazophenyl compound; dissolving the R2-bromoazophenyl compound and an aromatic cation in a third solvent for a nucleophilic substitution reaction, and adding an ammonium hexafluorophosphate solution thereto for an anion exchange reaction to obtain R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphate.

[0010] Optionally, the brominated aromatic hydrocarbon is 2-(2-bromoethyl)naphthalene or 9-(2-bromoethyl)-9H-carbazole, and the aromatic cation is pyridine or N-methylimidazole; the mass ratio of the R2-bromoazophenyl compound to the aromatic cation is 1:8-10;

[0011] Optionally, the mass ratio of 4,4'-dihydroxyazobenzene, 2-(2-bromoethyl), tetrabutylammonium iodide and cesium carbonate is (7-8.5):(5-6.5):1:(25-30); the mass ratio of 4,4'-dihydroxyazobenzene, 9-(2-bromoethyl)-9H-carbazole, tetrabutylammonium iodide and cesium carbonate is (1.5-2):1:(0.5-1):(6-10).

[0012] Optionally, when the brominated aromatic hydrocarbon is 2-(2-bromoethyl)naphthalene, (E)-4-((4-(2-(naphthalene-2-yl)ethoxy)phenyl)azo)phenol is (E)-4-((4-(2-(naphthalene-2-yl)ethoxy)phenyl)azo)phenol, the mass ratio of (E)-4-((4-(2-(naphthalene-2-yl)ethoxy)phenyl)azo)phenol, 1,2-dibromoethane, and cesium carbonate is 1:(1.5~2):(4.5~5.5), and the R2-bromoazophenyl compound is (E)-1-(4-(2-bromoethoxy)phenyl)-2-( 4-(2-(naphthalene-2-yl)ethoxy)phenyl)azobenzene; when the bromoaromatic hydrocarbon is 2-(2-bromoethyl)naphthalene and the aromatic cation is pyridine, R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphate is (E)-1-(2-(4-((4-(2-(naphthalene-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)pyridine-1-hexafluorophosphate; when the bromoaromatic hydrocarbon is 2-(2-bromoethyl)naphthalene and the aromatic cation is N-methylimidazole, R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2- The hexafluorophosphate is (E)-1-methyl-3-(2-(4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)-1H-imidazole-3-hexafluorophosphate; when the bromoaromatic hydrocarbon is 9-(2-bromoethyl)-9H-carbazole, the (E)-4-((4-(2-(9H-carbazol-9-yl)ethoxy)phenyl)azo)phenol is (E)-4-((4-(2-(9H-carbazol-9-yl)ethoxy)phenyl)azo)phenol, and the (E)-4-((4-(2-(9H-carbazol-9-yl)ethoxy)phenyl)azo)phenol is )phenol, 1,2-dibromoethane, and cesium carbonate have a mass ratio of 1:(10~12):(6~8), the R2-bromoazophenyl compound is (E)-9-(2-(4-((4-(2-bromoethoxy)phenyl)azo)phenoxy)ethyl)-9H-carbazole, and when the aromatic cation is pyridine, the R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphate is (E)-1-(2-(4-((4-(2-(9H-carbazol-9-yl)ethoxy)phenyl)azo)phenoxy)ethyl)pyridine-1-hexafluorophosphate.

[0013] Optionally, the preparation method of brominated aromatic hydrocarbons includes: dissolving a hydroxyl-substituted aromatic ring precursor and triphenylphosphine in a fourth solvent, and adding carbon tetrabromide solution thereto to carry out Applelot reaction to obtain brominated aromatic hydrocarbons; wherein the hydroxyl-substituted aromatic ring precursor is 2-(naphthalene-2-yl)ethanol or N-hydroxyethylcarbazole.

[0014] Optionally, the mass ratio of the hydroxyl-substituted aromatic ring precursor, triphenylphosphine, and carbon tetrabromide solution is 1:(1.2~1.5):(1.25~1.5); in the Applelot reaction, the temperature of adding the carbon tetrabromide solution is -2°C~2°C, the reaction temperature is 20~25°C, and the reaction time is 10~12h; the fourth solvent is acetonitrile.

[0015] Optionally, in the coupling reaction, the reaction environment is nitrogen, the reaction temperature is 110~130°C, the reaction time is 10~12h, and the first solvent is N,N-dimethylformamide or acetonitrile; in the etherification reaction, the reaction environment is nitrogen, the reaction temperature is 90~95°C, the reaction time is 10~12h, and the second solvent is N,N-dimethylformamide or acetonitrile; in the nucleophilic substitution reaction, the reaction environment is nitrogen, the reaction temperature is 110~120°C, the reaction time is 48~52h, and the third solvent is a mixed solution of 1,4-dioxane and N,N-dimethylformamide; in the anion exchange reaction, the reaction temperature is 20~25°C, and the reaction time is 5~6h.

[0016] To achieve the above objectives, the present application also provides a two-dimensional electrocatalytic hydrogen evolution material constructed based on cation-π interaction, comprising a plurality of R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphates obtained by the above-mentioned preparation method of the two-dimensional electrocatalytic hydrogen evolution monomer, wherein adjacent R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphates are connected end to end.

[0017] To achieve the above objectives, the present application also provides an application of the above-mentioned two-dimensional electrocatalytic hydrogen evolution material constructed based on cation-π interaction in catalytic hydrogen evolution.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] The present invention discloses a method for preparing a two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction, which optimizes its electronic properties and active sites by regulating the molecular structure, thereby improving the catalytic efficiency, without introducing specific metal anchoring sites. The catalyst molecules are obtained by introducing groups capable of cation-π interaction at both ends of an azobenzene molecule as a core, and the cation-π interaction between the conjugated aromatic ring π structure and the aromatic cation is utilized to promote the orderly assembly of these catalyst molecules in a head-to-tail alternating arrangement, thereby forming a two-dimensional material with a highly ordered structure. The cation-π interaction between adjacent catalyst molecules not only enhances the charge transfer capability within the two-dimensional material, but also provides a large specific surface area for the formed two-dimensional structure, which can significantly increase the exposure of hydrogen adsorption active sites, thereby significantly improving the electrocatalytic hydrogen evolution performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1This is the nuclear magnetic hydrogen spectrum of the product M1 of Example 1 in the preparation method of a two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction of this application;

[0021] Figure 2 This is a graph showing the capacitance test results of the product M1 of Example 1 in the preparation method of a two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction of this application;

[0022] Figure 3 This is a transmission electron micrograph of a two-dimensional electrocatalytic material based on M1 molecules in Example 1 of a method for preparing a two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction in this application;

[0023] Figure 4 This is a linear sweep voltammogram of the two-dimensional electrocatalytic material based on the M1 molecule in Example 1 of the preparation method of a two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction of this application;

[0024] Figure 5 This is the nuclear magnetic hydrogen spectrum of the product M2 of Example 2 in the preparation method of a two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction of this application;

[0025] Figure 6 This is a transmission electron micrograph of a two-dimensional electrocatalytic material based on M2 molecules in Example 2 of a method for preparing a two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction in this application;

[0026] Figure 7 This is the nuclear magnetic hydrogen spectrum of the product M3 of Example 3 in the preparation method of a two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction of this application;

[0027] Figure 8 This is a transmission electron micrograph of a two-dimensional electrocatalytic material based on M3 molecules in Example 3 of a method for preparing a two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction in this application;

[0028] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0029] To make the objectives, technical solutions, and advantages of this application more clear, the technical solutions of this application will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0030] The first embodiment of the present invention provides a two-dimensional electrocatalytic hydrogen evolution monomer, the structural formula of the monomer is:

[0031]

[0032] Among them, R1 is a cationic unit, R1 is C5H5N or C4H6N, R2 is a π unit, R2 is C 10 H8 is C 12 H8N.

[0033] A second embodiment of the present invention provides a method for preparing the above-mentioned two-dimensional electrocatalytic hydrogen evolution monomer, which specifically includes the following steps:

[0034] Step S1, dissolving 4,4'-dihydroxyazobenzene, a brominated aromatic hydrocarbon, tetrabutylammonium iodide, and cesium carbonate in a first solvent and conducting a coupling reaction under a nitrogen atmosphere at a reaction temperature of 110-130°C for 10-12 hours. After the reaction solution is cooled to room temperature, the solvent is removed, water is added to quench the reaction, and then extraction is performed with ethyl acetate under acidic conditions, followed by separation and purification by column chromatography to obtain (E)-4-((4-(2-(X-ethoxy)phenyl)azo)phenol;

[0035] For example, the brominated aromatic hydrocarbon is 2-(2-bromoethyl)naphthalene or 9-(2-bromoethyl)-9H-carbazole, and the first solvent is N,N-dimethylformamide or acetonitrile.

[0036] Among them, the preparation method of 2-(2-bromoethyl)naphthalene includes: dissolving a hydroxyl-substituted aromatic ring precursor and triphenylphosphine in a fourth solvent, and adding a carbon tetrabromide solution thereto at -2°C~2°C to carry out an Applelot reaction, the reaction temperature is 20~25°C, the reaction time is 10~12 hours, after the reaction is completed, the acetonitrile solvent is removed, water is added to quench the reaction, and then extraction is performed with dichloromethane, and then separation and purification are performed by column chromatography to obtain 2-(2-bromoethyl)naphthalene. The mass ratio of the hydroxyl-substituted aromatic ring precursor, triphenylphosphine, and carbon tetrabromide solution is 1:(1.2~1.5):(1.25~1.5).

[0037] For example, the hydroxy-substituted aromatic ring precursor is 2-(naphthalen-2-yl)ethanol or N-hydroxyethylcarbazole, and the fourth solvent is acetonitrile.

[0038] Furthermore, when the brominated aromatic hydrocarbon is 2-(2-bromoethyl), the mass ratio of 4,4'-dihydroxyazobenzene, 2-(2-bromoethyl), tetrabutylammonium iodide and cesium carbonate is (7-8.5):(5-6.5):1:(25-30), (E)-4-((4-(2-X-ethoxy)phenyl)azo)phenol is (E)-4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenol; When the hydrocarbon is 9-(2-bromoethyl)-9H-carbazole, the mass ratio of 4,4'-dihydroxyazobenzene, 9-(2-bromoethyl)-9H-carbazole, tetrabutylammonium iodide and cesium carbonate is (1.5-2):1:(0.5-1):(6-10), and (E)-4-((4-(2-X-ethoxy)phenyl)azo)phenol is (E)-4-((4-(2-(9H-carbazol-9-yl)ethoxy)phenyl)azo)phenol.

[0039] Step S2, dissolving (E)-4-((4-(2-X-ethoxy)phenyl)azo)phenol, 1,2-dibromoethane, and cesium carbonate in a second solvent, and conducting an etherification reaction under a nitrogen atmosphere at a reaction temperature of 90-95° C. for 10-12 hours. After the reaction, the acetonitrile solvent is removed, water is added to quench the reaction, and then extracted with ethyl acetate, followed by separation and purification by column chromatography to obtain an R2-bromoazophenyl compound; the second solvent is acetonitrile or N,N-dimethylformamide.

[0040] Wherein, when the brominated aromatic hydrocarbon is 2-(2-bromoethyl)naphthalene, the mass ratio of (E)-4-((4-(2-(X-ethoxy)phenyl)azo)phenol, 1,2-dibromoethane, and cesium carbonate is 1:(1.5-2):(4.5-5.5); the R2-bromoazophenyl compound is (E)-1-(4-(2-bromoethoxy)phenyl)-2-(4-(2-(naphthalen-2-yl)ethoxy)phenyl)azobenzene;

[0041] The brominated aromatic hydrocarbon is 9-(2-bromoethyl)-9H-carbazole, and the mass ratio of (E)-4-((4-(2-(X-ethoxy)phenyl)azo)phenol, 1,2-dibromoethane, and cesium carbonate is 1:(10-12):(6-8); the R2-bromoazophenyl compound is (E)-9-(2-(4-((4-(2-bromoethoxy)phenyl)azo)phenoxy)ethyl)-9H-carbazole.

[0042] Step S3, according to a mass ratio of 1:8~10, the R2-bromoazophenyl compound and the aromatic cation are dissolved in a third solvent, and a nucleophilic substitution reaction is carried out under a nitrogen atmosphere, the reaction temperature is 110~120°C, and the reaction time is 48~52h; after the reaction liquid is cooled to room temperature, the solvent is removed, and an excess of ammonium hexafluorophosphate solution is slowly added dropwise thereto to carry out anion exchange reaction, the reaction temperature is 20~25°C, and the reaction time is 5~6h. After the reaction is completed, the precipitated solid precipitate is filtered, washed with methanol 3 times, and dried to obtain R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphate.

[0043] Exemplarily, the aromatic cation is pyridine or N-methylimidazole; the third solvent is a mixed solution of 1,4-dioxane and N,N-dimethylformamide; and the ammonium hexafluorophosphate solution is a methanol solution of ammonium hexafluorophosphate.

[0044] Wherein, when the brominated aromatic hydrocarbon is 2-(2-bromoethyl)naphthalene and the aromatic cation is pyridine, R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphate is (E)-1-(2-(4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)pyridine-1-hexafluorophosphate, i.e., M1;

[0045] When the brominated aromatic hydrocarbon is 2-(2-bromoethyl)naphthalene and the aromatic cation is N-methylimidazole, R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphate is (E)-1-methyl-3-(2-(4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)-1H-imidazole-3-hexafluorophosphate, i.e., M2;

[0046] When the brominated aromatic hydrocarbon is 9-(2-bromoethyl)-9H-carbazole and the aromatic cation is pyridine, R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphate is (E)-1-(2-(4-((4-(2-(9H-carbazole-9-yl)ethoxy)phenyl)azo)phenoxy)ethyl)pyridine-1-hexafluorophosphate, i.e., M3.

[0047] In step S4, multiple R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphates are assembled in an orderly manner in a head-to-tail alternating arrangement to form a two-dimensional electrocatalytic hydrogen evolution material constructed based on cation-π interaction.

[0048] In this embodiment, a catalyst molecule is obtained by introducing groups capable of cation-π interaction at both ends of an azobenzene molecule as a core, and utilizing the cation-π interaction between the conjugated aromatic ring π structure and the aromatic cation to promote the orderly assembly of these catalyst molecules in an alternating head-to-tail arrangement, thereby forming a two-dimensional material with a highly ordered structure; the cation-π interaction between adjacent catalyst molecules not only enhances the charge transfer ability within the two-dimensional material, but also, because the formed two-dimensional structure has a large specific surface area, can significantly increase the exposure of hydrogen adsorption active sites, thereby significantly improving the electrocatalytic hydrogen evolution performance.

[0049] Example 1

[0050] Step S1, 1g 2-(naphthalene-2-yl)ethanol and 2g triphenylphosphine are dissolved in 150mL acetonitrile, and 100mL of acetonitrile solution of 2.4g carbon tetrabromide is slowly added thereto at 0°C, and the reaction is stirred at a constant temperature of 25°C for 12h. After the reaction is completed, the acetonitrile solvent is removed, 100mL of water is added to quench the reaction, and then 50mL of dichloromethane is used to extract twice, and then the solvent is removed by rotary evaporation after drying over anhydrous magnesium sulfate, and then separated and purified by column chromatography (eluent is n-hexane:ethyl acetate=100:1) to obtain 2-(2-bromoethyl)naphthalene as a white solid;

[0051] Step S2: 1.6 g of 4,4'-dihydroxyazobenzene, 1.2 g of 2-(2-bromoethyl)naphthalene, 370 mg of tetrabutylammonium iodide, and 4.3 g of cesium carbonate were dissolved in 200 mL of N,N-dimethylformamide, and the mixture was stirred and refluxed at 110°C under a nitrogen atmosphere for 16 hours. After the reaction solution was cooled to room temperature, the N,N-dimethylformamide solvent was removed, and the mixture was extracted three times with 500 mL of ethyl acetate under acidic conditions (pH = 2). The mixture was then dried over anhydrous magnesium sulfate and rotary evaporated to remove the solvent. The mixture was then separated and purified by column chromatography (eluent: n-hexane:ethyl acetate = 30:1) to obtain (E)-4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenol as a yellow solid.

[0052] Step S3: Dissolve 250 mg of (E)-4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenol, 191 mg of 1,2-dibromoethane, and 1.3 g of cesium carbonate in 150 mL of acetonitrile. The mixture is stirred and refluxed at 90°C under a nitrogen atmosphere for 12 hours. After the reaction, the acetonitrile solvent is removed, 100 mL of water is added, and the mixture is extracted three times with 100 mL of ethyl acetate. The mixture is then dried over anhydrous magnesium sulfate and the solvent is removed by rotary evaporation. The mixture is then separated and purified by column chromatography (eluent: n-hexane:ethyl acetate = 25:1) to obtain (E)-1-(4-(2-bromoethoxy)phenyl)-2-(4-(2-(naphthalen-2-yl)ethoxy)phenyl)azobenzene as a yellow solid.

[0053] In step S4, 240 mg of (E)-1-(4-(2-bromoethoxy)phenyl)-2-(4-(2-(naphthalen-2-yl)ethoxy)phenyl)azobenzene and 316 mg of pyridine were dissolved in 150 mL of a mixture of 1,4-dioxane and N,N-dimethylformamide (3:1). The mixture was stirred and refluxed at 110°C under a nitrogen atmosphere for 48 hours. After the reaction solution cooled to room temperature, the solvent was removed. The crude product was then dissolved in 20 mL of anhydrous methanol. The methanol solution of ammonium hexafluorophosphate was then slowly added dropwise to the methanol solution of the crude product. The mixture was stirred at room temperature for 5 hours. After the reaction was completed, the precipitated solid was filtered, washed three times with 20 mL of methanol, and dried to obtain a yellow solid product.

[0054] The product of this embodiment was detected. Figure 1 It can be seen from the H NMR spectrum that the product obtained in this example is (E)-1-(2-(4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)pyridine-1-hexafluorophosphate, and the structural formula is as follows:

[0055] ;

[0056] Capacitive detection of M1 molecules, from Figure 2 It can be seen that the double layer capacitance value of the M1 molecule is 6.5 mF / cm2, showing a large catalytic surface area and active site contact area, indicating a large exposure of the active sites.

[0057] Step S5, multiple (E)-1-(2-(4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)pyridine-1-hexafluorophosphates are assembled in an orderly manner in a head-to-tail alternating arrangement to form a two-dimensional electrocatalytic hydrogen evolution material; Figure 3 It can be seen from the transmission electron microscopy image that the two-dimensional electrocatalytic hydrogen evolution material prepared in this embodiment presents an ordered two-dimensional layered structure;

[0058] The two-dimensional electrocatalytic hydrogen evolution material obtained in this embodiment is used to electrocatalyze hydrogen evolution. Figure 4 It can be seen from the linear sweep voltammetry curve that when the current density is 10mA / cm 2 The overpotential is 170 mV, indicating that a high current density can be achieved at a low potential, which proves that the formation of cation π interaction inside the two-dimensional structure of this embodiment promotes the internal electron transfer rate.

[0059] Example 2

[0060] Step S1, 2g 2-(naphthalene-2-yl)ethanol and 4g triphenylphosphine are dissolved in 150mL acetonitrile, and 150mL of acetonitrile solution of 4.8g carbon tetrabromide is slowly added thereto at 0°C, and the reaction is stirred at 25°C for 12h. After the reaction is completed, the acetonitrile solvent is removed, 100mL of water is added to quench the reaction, and then 50mL of dichloromethane is used to extract 2 times, and then the solvent is removed by rotary evaporation after drying over anhydrous magnesium sulfate. Then, it is separated and purified by column chromatography (eluent is n-hexane:ethyl acetate=100:1) to obtain 2-(2-bromoethyl)naphthalene as a white solid;

[0061] Step S2: 3.2 g of 4,4'-dihydroxyazobenzene, 2.4 g of 2-(2-bromoethyl)naphthalene, 740 mg of tetrabutylammonium iodide, and 8.6 g of cesium carbonate were dissolved in 250 mL of N,N-dimethylformamide, and the mixture was stirred and refluxed at 110°C under a nitrogen atmosphere for 16 hours. After the reaction solution was cooled to room temperature, the N,N-dimethylformamide solvent was removed, and the mixture was extracted three times with 500 mL of ethyl acetate under acidic conditions (pH = 2). The mixture was then dried over anhydrous magnesium sulfate and rotary evaporated to remove the solvent. The mixture was then separated and purified by column chromatography (eluent: n-hexane:ethyl acetate = 30:1) to obtain (E)-4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenol as a yellow solid.

[0062] Step S3: Dissolve 500 mg of (E)-4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenol, 380 mg of 1,2-dibromoethane, and 2.6 g of cesium carbonate in 150 mL of acetonitrile and stir under reflux at 90°C under a nitrogen atmosphere for 12 hours. After the reaction, the acetonitrile solvent was removed, 100 mL of water was added, and the mixture was extracted three times with 100 mL of ethyl acetate. The mixture was then dried over anhydrous magnesium sulfate and the solvent was removed by rotary evaporation. The mixture was then separated and purified by column chromatography (eluent: n-hexane:ethyl acetate = 25:1) to obtain (E)-1-(4-(2-bromoethoxy)phenyl)-2-(4-(2-(naphthalen-2-yl)ethoxy)phenyl)azobenzene as a yellow solid.

[0063] In step S4, 480 mg of (E)-1-(4-(2-bromoethoxy)phenyl)-2-(4-(2-(naphthalen-2-yl)ethoxy)phenyl)azobenzene and 700 mg of N-methylimidazole were dissolved in 150 mL of a mixture of 1,4-dioxane and N,N-dimethylformamide (3:1). The mixture was stirred and refluxed at 110°C under a nitrogen atmosphere for 48 hours. After the reaction solution cooled to room temperature, the solvent was removed. The crude product was then dissolved in 20 mL of anhydrous methanol. The methanol solution of ammonium hexafluorophosphate was then slowly added dropwise to the methanol solution of the crude product. The mixture was stirred at room temperature for 5 hours. After the reaction was completed, the precipitated solid was filtered, washed three times with 20 mL of methanol, and dried to obtain a yellow solid product.

[0064] The product of this embodiment was detected. Figure 5 It can be seen from the H NMR spectrum that the product obtained in this example is (E)-1-methyl-3-(2-(4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)-1H-imidazole-3-hexafluorophosphate, and the structural formula is as follows:

[0065] ;

[0066] Step S5, multiple (E)-1-methyl-3-(2-(4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)-1H-imidazole-3-hexafluorophosphates are orderly assembled in a head-to-tail alternating arrangement to form a two-dimensional electrocatalytic hydrogen evolution material; Figure 6 It can be seen from the transmission electron microscope image that the two-dimensional electrocatalytic material prepared in this example presents an ordered two-dimensional layered structure.

[0067] Example 3

[0068] Step S1, 2.4 g of N-hydroxyethylcarbazole and 3.6 g of triphenylphosphine were dissolved in 180 mL of acetonitrile, and 120 mL of an acetonitrile solution of 4.5 g of carbon tetrabromide was slowly added thereto at 0° C., and the mixture was stirred at a constant temperature of 25° C. for 12 hours. After the reaction, the acetonitrile solvent was removed, and 120 mL of water was added to quench the reaction. The mixture was then extracted three times with 80 mL of dichloromethane, and then dried over anhydrous magnesium sulfate and the solvent was removed by rotary evaporation. The mixture was then separated and purified by column chromatography (eluent: n-hexane:ethyl acetate = 30:1) to obtain 9-(2-bromoethyl)-9H-carbazole as a white solid;

[0069] Step S2, dissolving 600 mg of 4,4'-dihydroxyazobenzene, 512 mg of 9-(2-bromoethyl)-9H-carbazole, 350 mg of tetrabutylammonium iodide, and 3.6 g of cesium carbonate in 220 mL of N,N-dimethylformamide, stirring and refluxing at 110°C under a nitrogen atmosphere for 16 hours, removing the solvent N,N-dimethylformamide after the reaction solution is cooled to room temperature, extracting three times with 500 mL of ethyl acetate under acidic conditions (pH = 2), then drying over anhydrous magnesium sulfate and rotary evaporation to remove the solvent, and then separating and purifying by column chromatography (eluent: n-hexane:ethyl acetate = 25:1) to obtain a yellow solid (E)-4-((4-(2-(9H-carbazol-9-yl)ethoxy)phenyl)azo)phenol;

[0070] Step S3: Dissolve 120 mg of (E)-4-((4-(2-(9H-carbazol-9-yl)ethoxy)phenyl)azo)phenol, 542 mg of 1,2-dibromoethane, and 600 mg of cesium carbonate in 180 mL of acetonitrile. Stir and reflux at 90°C under a nitrogen atmosphere for 12 hours. After the reaction, the acetonitrile solvent was removed, 120 mL of water was added, and the mixture was extracted three times with 100 mL of ethyl acetate. The mixture was then dried over anhydrous magnesium sulfate and the solvent was removed by rotary evaporation. The mixture was then separated and purified by column chromatography (eluent: n-hexane:ethyl acetate = 50:1) to obtain (E)-9-(2-(4-((4-(2-bromoethoxy)phenyl)azo)phenoxy)ethyl)-9H-carbazole as a yellow solid.

[0071] In step S4, 120 mg of (E)-9-(2-(4-((4-(2-bromoethoxy)phenyl)azo)phenoxy)ethyl)-9H-carbazole and 150 mg of pyridine were dissolved in 150 mL of a mixture of 1,4-dioxane and N,N-dimethylformamide (3:1). The mixture was stirred and refluxed at 110°C under a nitrogen atmosphere for 48 hours. After the reaction solution cooled to room temperature, the solvent was removed. The crude product was then dissolved in 40 mL of anhydrous methanol. The methanol solution of ammonium hexafluorophosphate was then slowly added dropwise to the methanol solution of the crude product. The mixture was stirred at room temperature for 5 hours. After the reaction was completed, the precipitated solid was filtered, washed three times with 40 mL of methanol, and dried to obtain a yellow solid product.

[0072] The product of this embodiment was detected. Figure 7 It can be seen from the H NMR spectrum that the product obtained in this example is (E)-1-(2-(4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)pyridine-1-hexafluorophosphate, and the structural formula is as follows:

[0073] ;

[0074] Step S5, multiple (E)-1-(2-(4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)pyridine-1-hexafluorophosphates are assembled in an orderly manner in a head-to-tail alternating arrangement to form a two-dimensional electrocatalytic hydrogen evolution material; Figure 8 It can be seen from the transmission electron microscope image that the two-dimensional electrocatalytic material prepared in this example presents an ordered two-dimensional layered structure.

[0075] The above are only preferred embodiments of the present application and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A two-dimensional electrocatalytic hydrogen evolution monomer, characterized in that: The structural formula of the monomer is: 、 or .

2. A method for preparing a two-dimensional electrocatalytic hydrogen evolution monomer according to claim 1, characterized in that: include: Dissolving 4,4'-dihydroxyazobenzene, aromatic bromide, tetrabutylammonium iodide, and cesium carbonate in a first solvent for a coupling reaction to obtain (E)-4-((4-(2-X-ethoxy)phenyl)azo)phenol; dissolving the (E)-4-((4-(2-X-ethoxy)phenyl)azo)phenol, 1,2-dibromoethane, and cesium carbonate in a second solvent for etherification reaction to obtain an R2-bromoazophenyl compound; The R2-bromoazophenyl compound and the aromatic cation are dissolved in a third solvent to carry out a nucleophilic substitution reaction, and an ammonium hexafluorophosphate solution is added thereto to carry out an anion exchange reaction to obtain R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphate, which is the two-dimensional electrocatalytic hydrogen evolution monomer according to claim 1, wherein R1 is a cationic unit in the monomer structural formula, and R2 is a π unit in the monomer structural formula; The brominated aromatic hydrocarbon is 2-(2-bromoethyl)naphthalene or 9-(2-bromoethyl)-9H-carbazole, and the aromatic cation is pyridine or N-methylimidazole; the mass ratio of the R2-bromoazophenyl compound to the aromatic cation is 1:8-10; When the brominated aromatic hydrocarbon is 2-(2-bromoethyl)naphthalene, The (E)-4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenol is (E)-4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenol; When the brominated aromatic hydrocarbon is 9-(2-bromoethyl)-9H-carbazole, (E)-4-((4-(2-(9H-carbazol-9-yl)ethoxy)phenyl)azo)phenol is (E)-4-((4-(2-(9H-carbazol-9-yl)ethoxy)phenyl)azo)phenol.

3. The method for preparing a two-dimensional electrocatalytic hydrogen evolution monomer according to claim 2, characterized in that: The mass ratio of the 4,4'-dihydroxyazobenzene, the 2-(2-bromoethyl), the tetrabutylammonium iodide and the cesium carbonate is (7-8.5): (5-6.5): 1: (25-30); The mass ratio of the 4,4'-dihydroxyazobenzene, the 9-(2-bromoethyl)-9H-carbazole, the tetrabutylammonium iodide and the cesium carbonate is (1.5-2):1:(0.5-1):(6-10).

4. The method for preparing a two-dimensional electrocatalytic hydrogen evolution monomer according to claim 2, wherein: When the brominated aromatic hydrocarbon is 2-(2-bromoethyl)naphthalene, The mass ratio of the (E)-4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenol, 1,2-dibromoethane, and cesium carbonate is 1:(1.5-2):(4.5-5.5), The R2-bromoazophenyl compound is (E)-1-(4-(2-bromoethoxy)phenyl)-2-(4-(2-(naphthalen-2-yl)ethoxy)phenyl)azobenzene; When the brominated aromatic hydrocarbon is 2-(2-bromoethyl)naphthalene and the aromatic cation is pyridine, the R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphate is (E)-1-(2-(4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)pyridine-1-hexafluorophosphate; When the brominated aromatic hydrocarbon is 2-(2-bromoethyl)naphthalene and the aromatic cation is N-methylimidazole, the R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphate is (E)-1-methyl-3-(2-(4-((4-(2-(naphthalen-2-yl)ethoxy)phenyl)azo)phenoxy)ethyl)-1H-imidazole-3-hexafluorophosphate; When the brominated aromatic hydrocarbon is 9-(2-bromoethyl)-9H-carbazole, The mass ratio of (E)-4-((4-(2-(9H-carbazol-9-yl)ethoxy)phenyl)azo)phenol, 1,2-dibromoethane, and cesium carbonate is 1:(10-12):(6-8), The R2-bromoazophenyl compound is (E)-9-(2-(4-((4-(2-bromoethoxy)phenyl)azo)phenoxy)ethyl)-9H-carbazole, When the aromatic cation is pyridine, the R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphate is (E)-1-(2-(4-((4-(2-(9H-carbazol-9-yl)ethoxy)phenyl)azo)phenoxy)ethyl)pyridine-1-hexafluorophosphate.

5. The method for preparing a two-dimensional electrocatalytic hydrogen evolution monomer according to claim 2, wherein: The preparation method of the brominated aromatic hydrocarbon comprises: dissolving a hydroxy-substituted aromatic ring precursor and triphenylphosphine in a fourth solvent, and adding a carbon tetrabromide solution thereto to carry out an Applelot reaction to obtain a brominated aromatic hydrocarbon; Wherein, the hydroxyl-substituted aromatic ring precursor is 2-(naphthalene-2-yl)ethanol or N-hydroxyethylcarbazole.

6. The method for preparing a two-dimensional electrocatalytic hydrogen evolution monomer according to claim 5, characterized in that: The mass ratio of the hydroxyl-substituted aromatic ring precursor, triphenylphosphine, and carbon tetrabromide solution is 1: (1.2-1.5): (1.25-1.5); In the Applelot reaction, the temperature of adding the carbon tetrabromide solution is -2°C to 2°C, the reaction temperature is 20°C to 25°C, and the reaction time is 10 to 12 hours; the fourth solvent is acetonitrile.

7. The method for preparing a two-dimensional electrocatalytic hydrogen evolution monomer according to claim 2, characterized in that: In the coupling reaction, the reaction environment is nitrogen, the reaction temperature is 110-130° C., the reaction time is 10-12 h, and the first solvent is N,N-dimethylformamide or acetonitrile; In the etherification reaction, the reaction environment is nitrogen, the reaction temperature is 90-95° C., the reaction time is 10-12 hours, and the second solvent is N,N-dimethylformamide or acetonitrile; In the nucleophilic substitution reaction, the reaction environment is nitrogen, the reaction temperature is 110-120° C., the reaction time is 48-52 hours, and the third solvent is a mixed solution of 1,4-dioxane and N,N-dimethylformamide; In the anion exchange reaction, the reaction temperature is 20-25° C. and the reaction time is 5-6 h.

8. A two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction, comprising: The preparation method of the two-dimensional electrocatalytic hydrogen evolution monomer according to claims 2-7 is used to obtain multiple R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphates, and adjacent R1-ethoxy-phenyl-azo-phenoxy-ethyl-R2-hexafluorophosphates are connected end to end.

9. Use of the two-dimensional electrocatalytic hydrogen evolution material based on cation-π interaction as claimed in claim 8 in catalytic hydrogen evolution.

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