Selenium molybdate compound constructed by rigid binary / polybasic carboxylic acid ligand as well as preparation method and application of selenium molybdate compound

Abstract

The invention discloses a selenium molybdate compound constructed by rigid binary / polybasic carboxylic acid ligands as well as a preparation method and application of the selenium molybdate compound. The molecular formula of the compound is as follows: compound 1, (Me2NH2) 14 [(Se2Mo12O42) 2 {O2CC2H2CO2} 3]. 12H2O; a compound 2 is (Me2NH2) 14 [(Se2Mo12O42) 2 {O2CC4H4CO2} 3]. 9H2O; the compound 3 is (TEAH) 28 [(Se2Mo12O42) 4 {C6H4 (CO2) 3} 4]. 27H2O. The polyoxometallate-based proton conductor constructed by the invention has good thermal stability and structural stability at the same time. The polyoxometallate-based proton conductor can maintain the structural stability through the covalent interaction between the ligand and the polyoxometallate (selenium molybdenum oxygen cluster), can realize rapid transmission of protons under the conditions of medium temperature (100 DEG C) and high humidity (98% RH), and meets the requirements of high-performance proton conductive materials in the solid electrolyte material market.

Description

Technical Field

[0001] The invention relates to the technical field of proton conductor materials, in particular to a selenomolybdate compound constructed with a rigid binary / polycarboxylic acid ligand, and a preparation method and application thereof. Background Art

[0002] Global economic development has led to an increase in energy demand. Traditional fossil energy is facing depletion and environmental pollution. The development of new energy conversion and storage technologies is urgent. Fuel cells, as a new green energy technology, can directly convert chemical energy into electrical energy. While improving the performance and efficiency of related technologies, they can also promote energy transformation. At present, some proton conduction materials based on polyoxometalates, referred to as polyacids (POMs), have been developed. This type of material has shown a relatively excellent proton transfer rate (10 -4 ~10 -2 S cm -1 ), but the further practical application of polyacid-based proton conductors is limited by the fact that the polyacid skeleton is prone to water loss and collapse in the air and the poor structural stability. In addition, the polyacid structural skeleton is susceptible to thermal decomposition, which is another major problem that needs to be solved urgently. Therefore, the development of POMs materials with efficient proton conduction performance still faces huge challenges.

[0003] New solid-state energy-related devices, especially fuel cells, are in urgent need of high-performance proton-conducting materials. Polyoxometalates (POMs) are nanoscale polyoxometalates, usually composed of pre-transition metals (including V, Mo, W, etc.) in high oxidation states. The surface of this type of material structure is oxygen-rich and the anion main structure has a high negative charge, which can more effectively attract protons and easily combine with water molecules, build a continuous hydrogen bond network, increase the migration path of protons, and thus improve the proton transfer efficiency of the material. Summary of the invention

[0004] In order to solve the above technical problems, the first purpose of the present invention is to provide a selenomolybdate compound constructed by a rigid binary / polycarboxylic acid ligand, the second purpose is to provide a preparation method thereof, and the third purpose is to provide an application thereof. The present invention proposes a new construction strategy, and the selenomolybdate-based proton conductor material constructed in this way not only has a high proton conductivity under the conditions of 98% relative humidity and 100°C temperature, but also its chemical structure can remain stable after the electrochemical reaction ends.

[0005] In order to achieve the above first purpose, the technical solution of the present invention is: a selenomolybdate compound constructed by a rigid dibasic / polybasic carboxylic acid ligand, characterized by being the following three compounds with the following molecular formula:

[0006] Compound 1, (Me 2 NH 2) 14 [(Se 2 Mo 12 O 42 ) 2 {O 2 CC 2 H 2 CO 2} 3 ]·12H 2 O;

[0007] Compound 2, (Me 2 NH 2 ) 14 [(Se 2 Mo 12 O 42 ) 2 {O 2 CC 4 H 4 CO 2} 3 ]·9H 2 O;

[0008] Compound 3, (TEAH) 28 [(Se 2 Mo 12 O 42 ) 4 {C 6 H 4 (CO 2 ) 3} 4 ]·27H 2 O.

[0009] The polyoxometalate-based proton conductor constructed by the present invention has good thermal stability and structural stability. The polyoxometalate-based proton conductor can maintain its structural stability through the covalent interaction between the ligand and the polyoxometalate (selenium molybdenum oxometalate) cluster, and can also realize the rapid transmission of protons under medium temperature (100°C) and high humidity (98%RH) conditions, meeting the demand for high-performance proton conductive materials in the solid electrolyte material market.

[0010] The second object of the present invention is achieved as follows: A method for preparing a selenomolybdate compound constructed with a rigid dibasic / polybasic carboxylic acid ligand, characterized in that compound 1 is prepared according to the following method: weigh (NH 4 ) 6 Mo 7 O 24 ·4H 2 O and Na 2 SeO 3Deionized water was added to the reaction container and mixed evenly; fumaric acid was added to the mixed solution, and the reaction was continued with stirring to obtain a clear colorless solution, the pH was adjusted to 3.2, and the solution was stirred at room temperature. Dimethylamine hydrochloride was added, the solution was stirred thoroughly, and the solution was filtered to retain the supernatant. The solvent was slowly evaporated at room temperature to precipitate colorless rectangular flaky crystals to obtain compound 1.

[0011] In the above scheme: (NH 4 ) 6 Mo 7 O 24 ·4H 2 O、Na 2 SeO 3 , fumaric acid and dimethylamine hydrochloride has a molar ratio of 1:1:1:3.68.

[0012] Compound 2 was prepared as follows: (NH 4 ) 6 Mo 7 O 24 ·4H 2 O and Na 2 SeO 3 Deionized water was added to the reaction container and mixed evenly; trans, trans-muconic acid was added to the mixed solution, the reaction was continued with stirring, the pH was adjusted to 2.6, the mixture was stirred at room temperature, dimethylamine hydrochloride was added, the mixture was stirred thoroughly, the mixture was filtered, the supernatant was retained, the solvent was slowly evaporated at room temperature, and colorless needle-shaped crystals were precipitated to obtain compound 2.

[0013] In the above scheme: (NH 4 ) 6 Mo 7 O 24 ·4H 2 O、Na 2 SeO 3 The molar ratio of trans, trans-muconic acid and dimethylamine hydrochloride is 1:1:0.5:3.68.

[0014] Compound 3 was prepared as follows: (NH 4 ) 6 Mo 7 O 24 ·4H 2 O and Na 2 SeO 3 Deionized water was added to the reaction container and mixed evenly; 1,3,5-benzenetricarboxylic acid was added to the mixed solution, the reaction was continued with stirring, and the solution was filtered. The pH of the filtrate was adjusted to 2.6, and the solution was stirred at room temperature. Triethanolamine hydrochloride was added, the solution was stirred thoroughly, and the solution was filtered. The supernatant was retained, and the solvent was slowly evaporated at room temperature to precipitate rhombus-shaped flaky crystals to obtain compound 3.

[0015] In the above scheme: (NH 4 ) 6 Mo 7 O 24 ·4H 2 O、Na 2 SeO 3 The molar ratio of 1,3,5-benzenetricarboxylic acid and triethanolamine hydrochloride is 1:1:1:8.

[0016] The third object of the present invention is achieved by: using the selenomolybdate compound constructed by the rigid dibasic / polybasic carboxylic acid ligand as a proton conductor material for the transfer and transmission of protons.

[0017] The present invention proposes a novel strategy for constructing polyacid-based electron conductor materials. The surface of the constructed selenomolybdate compounds (1-3) has abundant terminal oxygen atoms and a large number of free counter cations (TEAH + ,DMA + ), which can be absorbed or bound by H 2 O molecules form a continuous hydrogen bond network to increase the proton hopping path, achieving a higher proton conductivity (>10 -3 S cm -1 ).

[0018] Since POMs compounds usually have a clear molecular structure, the formation of the compound can be pre-designed at the molecular level. 2 L 1 ), trans, trans-muconic acid (H 2 L 2 ) and 1,3,5-trimethylbenzenecarboxylic acid (H 3 L 3 ) as a bridging ligand, covalently bonded with selenium molybdenum oxygen clusters to form three novel selenomolybdate compounds. In addition, the results of proton conduction experiments showed that the three compounds exhibited good proton conduction performance under medium temperature (100°C) and high humidity (98% RH) conditions, and the proton conductivity σ of the three compounds reached 1.06×10 -2 Scm -1 (1) 1.04×10 -2 S cm -1 (2) 5.59×10 -3 S cm -1 (3).

[0019] The single crystal X-ray diffraction results show that the three compounds of the present invention have the same structural unit [Se 2 Mo 12 O42 ] 4- ({Se 2 Mo 12}), the novel {Se 2 Mo 12 The structural unit has a twelve-core bilayer configuration, and the single layer {SeMo 6 The unit presents an Anderson-type structure and can be regarded as a 3} as the center, with six {MoO 6} octahedrons are connected by sharing corners and edges. 6 The structural units are connected by six "Mo-O-Mo" bonds and arranged in a 60° stack. 2 Mo 12 The structural unit is difficult to separate in the form of a monomer, so it is speculated that the covalent modification of the carboxylic acid ligand is of great significance to the stability of the structural unit, by providing a carboxyl group to bond with the two edge-shared molybdenum octahedrons, bridging two or more {Se 2 Mo 12}unit.

[0020] Infrared spectra show that {Se 2 Mo 12 Units in 940-880cm -1 (Mo=O stretching vibration) and 770-660cm -1 The similar characteristic peaks in the range of (Mo-O-Mo stretching vibration) were observed in the polyanions 1-3, while the polyanions 1-3 could remain stable in a wider range of 2.0 to 11.0, indicating that the formed covalent frameworks have strong resistance to hydrolysis. Powder X-ray diffraction (PXRD) confirmed the phase purity of 1-3, and its pattern matched well with the simulated single X-ray diffraction pattern. Thermal stability analysis showed that in N 2 Under the atmosphere, these POM materials can maintain thermal stability up to 180°C.

[0021] Polyacids are a class of metal oxygen cluster compounds with oxygen-rich surfaces and high negative charges, so they can fully attract protons and easily establish hydrogen bonds with water molecules, increase the proton jump path, and improve the proton transmission efficiency. The synthetic strategy proposed in this invention can prepare compounds with unique molecular structures, excellent thermal stability and chemical stability. Under the conditions of 98% RH and 373K, the proton conductivity of the three compounds is approximately 10 -2 S cm -1 , has excellent proton transport ability and has great application prospects as a proton conductor material. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The crystal structure of compound 1.

[0023] Figure 2 The crystal structure of compound 2.

[0024] Figure 3 The crystal structure of compound 3.

[0025] Figure 4 This is the thermogravimetric analysis curve of compound 1.

[0026] Figure 5 This is the thermogravimetric analysis curve of compound 2.

[0027] Figure 6 This is the thermogravimetric analysis curve of compound 3.

[0028] Figure 7 This is the infrared spectrum of compounds 1 to 3.

[0029] Figure 8 is the H NMR spectrum of compound 1.

[0030] Fig. 9 This is the H NMR spectrum of compound 2.

[0031] Fig.10 This is the H NMR spectrum of compound 3.

[0032] Fig.11 This is the water vapor adsorption-desorption curve of compound 1.

[0033] Fig.12 This is the water vapor adsorption-desorption curve of compound 2.

[0034] Fig.13 This is the water vapor adsorption-desorption curve of compound 3.

[0035] Fig.14 Nyquist curves and Arrhenius plots of compounds 1 to 3.

[0036] Fig.15 Powder X-ray diffraction patterns of compound 1 before and after proton conduction and single crystal XRD simulation.

[0037] Fig.16 Powder X-ray diffraction patterns of compound 2 before and after proton conduction and single crystal XRD simulation.

[0038] Fig.17 Powder X-ray diffraction patterns of compound 3 before and after proton conduction and single crystal XRD simulation. DETAILED DESCRIPTION

[0039] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0040] Example 1

[0041] The preparation method of the selenomolybdate compound 1 is as follows:

[0042] (Me 2 NH 2 ) 14 [(Se 2 Mo 12 O 42 ) 2 {O 2 CC 2 H 2 CO 2} 3 ·12H 2 O(1):

[0043] Weigh (NH 4 ) 6 Mo 7 O 24 ·4H 2 O (1.235 g, 1.0 mmol, ammonium heptamolybdate) and Na 2 SeO 3 (0.173 g, 1.0 mmol) into a beaker, add 20 mL of deionized water, and mix evenly. Add fumaric acid (0.116 g, 1.0 mmol) to the mixed solution, continue stirring for 30 minutes to obtain a clear and colorless solution. Then adjust the pH of the solution to 3.2 using 6.0 M HCl. Stir at room temperature for 6 hours, add dimethylamine hydrochloride (300 mg, 3.68 mmol), stir well, filter, retain the supernatant, and slowly evaporate the solvent at room temperature. Colorless rectangular sheet crystals start to precipitate after one week, which is compound 1. The yield of the collected product is 1.20 g, and the calculated yield is approximately 79% (based on Mo). The elemental analysis results are as follows: Theoretical values (%): Mo 45.04, Se 6.13, H 2.74, C 9.20, N 3.76; Experimental values (%): Mo 44.17, Se 8.31, H 4.36, C 6.41, N 5.11.

[0044] Example 2

[0045] The preparation method of compound 2 is as follows:

[0046] (Me 2 NH 2 ) 14 [(Se 2 Mo 12 O 42 ) 2 {O2 CC 4 H 4 CO 2} 3 ]·9H 2 O(2)

[0047] Weigh (NH 4 ) 6 Mo 7 O 24 ·4H 2 O (1.235 g, 1.0 mmol, ammonium heptamolybdate) and Na 2 SeO 3 (0.173g, 1.0mmol) was placed in a beaker, 20mL of deionized water was added, and the mixture was mixed well. Trans, trans-muconic acid (0.071g, 0.5mmol) was added to the mixed solution, and after reacting for 30 minutes, the pH of the solution was adjusted to 2.6 with 6.0M HCl. After reacting at room temperature for 6 hours, dimethylamine hydrochloride (1.0mL, 300mg / mL) was added and stirred thoroughly, the solution was filtered, the supernatant was retained, the solvent was slowly evaporated at room temperature, and colorless needle-shaped crystals were precipitated after about 2 days, which was compound 2. The product yield was 0.80g, and the calculated yield was about 53% (based on Mo). The results of elemental analysis are as follows: theoretical value (%): Mo 44.84, Se 6.10, H 2.73, C 10.58, N 3.74; experimental value (%): Mo 42.81, Se 8.11, H 4.71, C 8.22, N 2.00.

[0048] Example 3

[0049] Preparation of compound 3:

[0050] (TEAH) 28 [(Se 2 Mo 12 O 42 ) 4 {C 6 H 4 (CO 2 ) 3} 4 ]·27H 2 O(3):

[0051] Weigh (NH 4 ) 6 Mo 7 O 24 ·4H 2 O (1.235 g, 1.0 mmol, ammonium heptamolybdate) and Na 2 SeO 3(0.173g, 1.0mmol) in a beaker, add 20mL of deionized water and mix well. Add 1,3,5-benzenetricarboxylic acid (0.210g, 1.0mmol) to the mixed solution, after sufficient reaction, filter, and adjust the solution pH to 2.6 with 6.0M HCl. Stir at room temperature for 6 hours, add 8.0mmol of triethanolamine hydrochloride and stir well, filter, and keep the supernatant and slowly evaporate at room temperature. The product precipitates in the form of rhombus flaky crystals after about two weeks, that is, compound 3 is obtained. The collected product yield is 1.10g, and the calculated yield is about 56% (based on Mo). The results of elemental analysis are as follows: theoretical value (%): Mo 34.24, Se 4.69, H 3.88, C 18.21, N 2.91; experimental value (%): Mo 33.81, Se 4.11, H 4.71, C 17.22, N 2.11.

[0052] Crystal structure and description of the compound

[0053] like Figure 1-3 The single crystal X-ray diffraction results show that the three compounds have the same structural unit [Se 2 Mo 12 O 42 ] 4- ({Se 2 Mo 12}), the novel {Se 2 Mo 12 The structural unit has a twelve-core bilayer configuration, and the single layer {SeMo 6} unit presents an Anderson-type structure and can be regarded as a 3} as the center, with six {MoO 6} octahedrons are connected by sharing corners and edges. 6 The structural units are connected by six "Mo-O-Mo" bonds and arranged in a 60° stack. 2 Mo 12 The structural unit is difficult to separate in the form of a monomer, so it is speculated that the covalent modification of the carboxylic acid ligand is of great significance to the stability of the structural unit, by providing a carboxyl group to bond with the two edge-shared molybdenum octahedrons, bridging two or more {Se 2 Mo 12}unit.

[0054] Thermal stability analysis of compounds

[0055] like Figure 4-6The thermal decomposition process of compounds 1 to 3 can be roughly divided into two stages. In the first stage (30-180°C), the weight loss ratio of compound 1 is 4.07%, corresponding to the loss of 12 lattice water molecules in the structure; the weight loss ratio of compound 2 is 3.14%, which can be attributed to 9 lattice water molecules; the weight loss ratio of compound 3 is 3.58%, corresponding to 27 lattice water molecules. In the second stage (180-800°C), the weight loss ratios of the three compounds all increased significantly, corresponding to the loss of organic ligands, SeO 2 Thermogravimetric analysis results show that the three compounds (1-3) proposed in this patent all exhibit excellent thermal stability in the range of 30-180°C, which is of great significance for maintaining good structural stability in practical applications as proton conductor materials.

[0056] Infrared spectroscopy analysis of compounds

[0057] like Figure 7 Comparison of the infrared characteristic absorption peaks of compounds 1 to 3 revealed that: since compounds 1 to 3 all contain the same anionic group ([Se 2 Mo 12 O 42 ] 4- ), so at 900~600cm -1 The infrared peaks of the three compounds are exactly the same within the wavelength range. -1 and 762~662cm -1 The characteristic absorption peaks at 1564-1378 cm -1 In the wavelength range, the peaks of compounds 1 to 3 are quite different. The peaks in this range are mainly related to [Se 2 Mo 12 O 42 ] 4- Fumaric acid (H 2 L 1 ), trans, trans-muconic acid (H 2 L 2 )、1,3,5-Tricarboxylic acid (H 2 L 3 ) has a different stretching vibration frequency of the carboxyl peak, which is reflected in the red light spectrum. In addition, the characteristic absorption peak of the free carboxyl group is generally located at 1700-1740 cm -1 In comparison, the vibration absorption peaks of the carboxyl groups in the structures of compounds 1 to 3 all underwent a significant red shift. The reason for this is that the interaction between the carboxyl groups and the metal Mo induces a change in the electron cloud density, which promotes the ν(COO- ) vibration shifted to the low frequency direction. This result once again confirmed that the introduced carboxylic acid ligand has been linked to {Se 2 Mo 12}The structural unit completes the bridging.

[0058] H NMR spectrum analysis of compounds

[0059] Collect the crystal samples of compounds 1 to 3 and the powders of fumaric acid, trans-muconic acid and 1,3,5-trimethylbenzene carboxylic acid samples and completely dissolve them in D 2 O, the H NMR spectrum is as follows Figure 8-10 The results showed that the peak signal of hydrogen atoms in the compound 1 sample corresponded to the hydrogen atom signal in the bridging ligand (fumaric acid) in the structure. In addition, the broadening of the NMR hydrogen spectrum peak due to the coordination between the ligand and the metal atom further confirmed the main structure of compound 1. Compound 2 and trans- and trans-muconic acid ligands were dissolved in D 2 After O, the peak position and integrated area of ​​the hydrogen atom signal peak further confirmed the main structure of compound 2. Similarly, for compound 3, the signal peak of the 1,3,5-trimethylbenzene trimesic acid ligand involved in the coordination was significantly offset compared with the free trimethylbenzene trimesic acid ligand, and the corresponding signal peak was broadened. Analysis shows that after the ligand is coordinated with the metal, its electron cloud density is affected by the metal center, and part of the electron cloud is localized around the metal, which in turn affects its local magnetic field, resulting in changes in the position and width of the NMR spectrum peak. The above results can also show that the three compounds have good stability in aqueous solution and their structures are not destroyed.

[0060] Determination of water vapor adsorption content of compounds

[0061] like Figure 11-12 The water vapor adsorption-desorption isotherms of compounds 1-3 show that the unique pore structures of the three compounds are conducive to the adsorption of water molecules. With the continuous increase of relative pressure, the adsorption amount of water by compounds 1-3 is also increasing. The maximum water vapor absorption amount of compounds 1-3 can reach 79, 85 and 90 mg / g, respectively.

[0062] Determination of proton conductivity and activation energy of compounds

[0063] At room temperature and 40% relative humidity (RH), the proton conductivity (σ) of compounds 1 to 3 is 3.37×10 –7 , 3.67×10 –7 and 1.51×10 -7 S cm –1As the ambient humidity increases further (set to 76%, 86%, and 98% RH respectively), the σ of the three compounds also show a significant upward trend. At room temperature and 98% RH, the σ of the three compounds can reach 8.60×10 –4 , 2.05×10 -4 and 1.42×10 -4 S cm -1 .

[0064] Under 98% RH conditions, by setting different ambient temperatures to monitor the changes in compound σ, the transport mechanism of protons inside the electrolyte material can be analyzed. By establishing the Arrhenius plot ( Fig.14 ), and the activation energy required for proton transfer within compounds 1 to 3 (E a ) values ​​are 0.27, 0.25, and 0.26 eV, respectively, all following the "jumping mechanism". With the unique structural advantage, the protons inside the compound, with the assistance of absorbed water molecules and free anions, establish a rich hydrogen bond network with the oxygen atoms at the end of the anion structure, providing abundant "jumping" paths for the transfer and transmission of protons, thereby increasing the proton transmission rate.

[0065] Analysis of structural stability of compounds after proton conduction

[0066] The sample powders were collected before and after the proton conduction reaction, and the collected samples were analyzed using powder X-ray diffraction technology. From the powder X-ray diffraction diagram, it can be found that under high humidity and medium temperature conditions, the diffraction peak positions of compound 1 to 3 samples are consistent with those before the test. This shows that the structural frameworks of the three compounds have not been destroyed, and the crystallinity has not been greatly affected, and they can maintain a high chemical stability.

[0067] Table 1 Crystal diffraction data of compounds 1 to 3

[0068]

[0069] R 1 =∑||F o |-|F c | / ∑|F o |.wR 2 =[∑w(F o 2 -F c 2 ) 2 / ∑w(F o 2 ) 2 ] 1 / 2

[0070] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A selenomolybdate compound constructed with a rigid dibasic / polybasic carboxylic acid ligand, characterized in that: The following three compounds have the following molecular formulas: Compound 1, (Me2NH2) 14 [(Se2Mo 12 O 42 )2{O2CC2H2CO2}3]·12H2O; Compound 2, (Me2NH2) 14 [(Se2Mo 12 O 42 )2{O2CC4H4CO2}3]·9H2O; Compound 3, (TEAH) 28 [(Se2Mo 12 O 42 )4{C6H4(CO2)3}4]·27H2O.

2. A method for preparing the selenomolybdate compound constructed with the rigid dibasic / polybasic carboxylic acid ligands according to claim 1, characterized in that: Compound 1 was prepared as follows: (NH4)6Mo7O 24 ·4H2O and Na2SeO3 were placed in a reaction container, deionized water was added, and the mixture was mixed evenly; fumaric acid was added to the mixed solution, and the reaction was continued under stirring to obtain a clear colorless solution, the pH was adjusted to 3.2, and the mixture was stirred at room temperature, dimethylamine hydrochloride was added, the mixture was stirred thoroughly, and the mixture was filtered to retain the supernatant, and the solvent was slowly evaporated at room temperature to precipitate colorless rectangular flaky crystals to obtain compound 1.

3. The method for preparing the selenomolybdate compound constructed with rigid dibasic / polybasic carboxylic acid ligands according to claim 2, characterized in that: (NH4)6Mo7O 24 The molar ratio of 4H2O, Na2SeO3, fumaric acid and dimethylamine hydrochloride is 1:1:1:3.

68.

4. A method for preparing the selenomolybdate compound constructed with rigid dibasic / polybasic carboxylic acid ligands as claimed in claim 1, characterized in that: Compound 2 was prepared as follows: (NH4)6Mo7O 24 ·4H2O and Na2SeO3 are placed in a reaction container, deionized water is added, and the mixture is mixed evenly; trans, trans-muconic acid is added to the mixed solution, the reaction is continued with stirring, the pH is adjusted to 2.6, the mixture is stirred at room temperature, dimethylamine hydrochloride is added, the mixture is stirred thoroughly, and the mixture is filtered, the supernatant is retained, the solvent is slowly evaporated at room temperature, and colorless needle-shaped crystals are precipitated to obtain compound 2.

5. The method for preparing the selenomolybdate compound constructed with rigid dibasic / polybasic carboxylic acid ligands according to claim 4, characterized in that: (NH4)6Mo7O 24 The molar ratio of 4H2O, Na2SeO3, trans, trans-muconic acid and dimethylamine hydrochloride is 1:1:0.5:3.

68.

6. A method for preparing the selenomolybdate compound constructed with rigid dibasic / polybasic carboxylic acid ligands as claimed in claim 1, characterized in that: Compound 3 was prepared as follows: (NH4)6Mo7O 24 ·4H2O and Na2SeO3 were placed in a reaction container, deionized water was added, and the mixture was mixed evenly; 1,3,5-benzenetricarboxylic acid was added to the mixed solution, the reaction was continued under stirring, and the mixture was filtered. The pH of the filtrate was adjusted to 2.6, and the mixture was stirred at room temperature. Triethanolamine hydrochloride was added, the mixture was stirred thoroughly, and the mixture was filtered. The supernatant was retained, and the solvent was slowly evaporated at room temperature to precipitate rhombic flaky crystals to obtain compound 3.

7. A method for preparing the selenomolybdate compound constructed with rigid dibasic / polybasic carboxylic acid ligands as claimed in claim 6, characterized in that: (NH4)6Mo7O 24 The molar ratio of 4H2O, Na2SeO3, 1,3,5-benzenetricarboxylic acid and triethanolamine hydrochloride is 1:1:1:

8.

8. Use of the selenomolybdate compound constructed with the rigid dibasic / polybasic carboxylic acid ligands as claimed in claim 1 as a proton conductor material for the transfer and transmission of protons.

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