Preparation method and application of a coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand

Abstract

The present invention belongs to the technical field of coordination polymers, and relates to a preparation method and application of a coordination polymer based on a 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand. The chemical formula of the coordination polymer is [CoCA(H2O)2] n ‧nH2O (n is a natural number from 1 to positive infinity), and the preparation method is as follows: using 2,5-dichloro-3,6-dihydroxy-p-benzoquinone (H2CA) as an organic ligand, and using a cobalt salt as a metal center, directly growing through coordination in a solvent. The advantages of the present invention are as follows: the obtained coordination polymer has a simple synthesis method, easily available raw materials, is easy to operate, has mild reaction conditions, low cost, and the prepared coordination polymer has good stability. When used as a catalyst for the electrocatalytic water decomposition oxidation reaction, it has advantages such as good oxygen evolution performance, low overpotential, and high stability.

Description

Technical Field

[0001] The present invention belongs to the technical field of coordination polymers, and relates to a preparation method and application of a coordination polymer based on a 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand. Background Art

[0002] With the growth of the world's population and the acceleration of the industrialization process, the energy crisis and environmental problems caused by the excessive consumption of fossil fuels and the increase in carbon emissions have promoted the exploration of renewable and clean energy. As a green and clean new energy, hydrogen energy is considered an effective alternative to fossil energy, and high-purity hydrogen produced by water splitting is an effective hydrogen production route. There are two key electrochemical processes in the water electrolysis process, namely the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER). Compared with the hydrogen evolution reaction, the oxygen evolution reaction is a four-electron transfer process with multiple intermediate states, resulting in slow kinetics and a large overpotential. In order to promote the large-scale application of hydrogen production by electrolyzed water, how to design an efficient catalyst to reduce the overpotential of OER and meet the requirements of practical applications is a key issue in current scientific research.

[0003] Generally speaking, the main function of an electrocatalytic oxygen evolution (OER) catalyst is to adsorb reactants on the surface to form adsorbed intermediates (such as: M-OOH, M-O, etc.), thereby promoting the charge transfer between the electrode and the reactants and accelerating the reaction. An ideal electrocatalytic oxygen evolution catalyst must meet the following conditions: First, the catalyst must have high catalytic activity and be able to obtain a high current density under low overpotential conditions. Second, it has excellent stability. Third, it needs to have a large specific surface area to increase the contact area between the electrolyte and the catalyst. Currently, noble metals and their oxides such as: Ru, Ir, RuO 2 and IrO 2is the most effective OER catalyst. However, due to the scarcity and high cost of these materials, their industrial applications are greatly limited. Therefore, it is of great significance to develop new catalysts, reduce the energy consumption of water decomposition, and solve the problem of high energy consumption in current water electrolysis. Although non-precious metal catalysts such as transition metal phosphides, sulfides, oxides, nitrides, selenides, and carbides have certain catalytic properties, there are still problems such as high overpotential during the catalytic process, poor cycle durability caused by the instability of the catalyst in the electrolyte, and complex catalytic preparation methods, which are not sufficient to meet the industrial requirements. Coordination polymers (CPs) formed by connecting metal centers and organic ligands through coordination bonds have been widely studied in the fields of catalysis, fluorescence, adsorption, and energy storage due to the highly adjustable nature of their composition, structure, and properties. Compared with traditional electrocatalytic materials, the complex structure not only has highly active metal centers but also has advantages such as rich coordination environments, precisely adjustable structures and compositions, and has great development potential in the catalytic field. For example, Patent CN107118217A discloses a copper porphyrin complex for electrocatalytic oxygen evolution reaction and its preparation method. A copper porphyrin complex [C 108 Cu 2 N 20 O 4 H 0.25 was prepared using 5,10,15,20-tetracyano phenyl porphyrin organic ligand and copper nitrate trihydrate, and used for electrocatalytic oxygen evolution reaction. Its oxygen evolution overpotential at a current density of 10 mA / cm 2 is 1.66 V (vs. RHE, relative to the reversible hydrogen electrode). However, the electrocatalytic water oxidation reaction performance of coordination polymers needs to be further improved. Summary of the Invention

[0004] In view of the above technical problems, the present invention proposes a preparation method and application of a coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand. The preparation method has the advantages of simple method and cheap and easily available raw materials; it has good catalytic performance when used as an electrocatalytic water oxidation reaction and can be applied to electrocatalytic electrode materials.

[0005] To achieve the above object, the technical solution of the present invention is realized as follows:

[0006] A coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand, with the chemical formula [CoCA(H 2 O) 2 n ‧nH 2 O, where n is a natural number from 1 to positive infinity, and 2,5-dichloro-3,6-dihydroxy-p-benzoquinone is the organic ligand; it belongs to the monoclinic system, space group Cc ​, the unit cell parameters are α = γ = 90°, β = 94.203(4)°, the unit cell volume is V = 1687.11(11), Z = 4. Each cobalt metal has a six-coordinate structure, coordinating with four oxygens from 2,5-dichloro-3,6-dihydroxy-p-benzoquinone and two oxygens from water molecules respectively. Adjacent Co metal centers are connected into a one-dimensional chain through ligand bridges.

[0007] A preparation method of a coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand, comprising the following steps:

[0008] Weigh cobalt salt and dissolve it in a mixed solution of methanol and water with a volume ratio of 3:1, denoted as solution A. Weigh 2,5-dichloro-3,6-dihydroxy-p-benzoquinone and dissolve it in a mixed solution of methanol and water with a volume ratio of 1:1, denoted as solution B. Under stirring, add solution A dropwise to solution B. After the titration is completed, continue stirring for 30 min and then let it stand for 3 - 7 days. After the reaction is completed, filter and wash it 3 times with distilled water to obtain dark red strip crystals, which are the coordination polymer described above.

[0009] Furthermore, the type of cobalt salt is cobalt acetate tetrahydrate or cobalt chloride hexahydrate.

[0010] Furthermore, the molar ratio of the cobalt salt to 2,5-dichloro-3,6-dihydroxy-p-benzoquinone is (2 - 3):1.

[0011] Furthermore, the concentration range of the cobalt salt in solution A is: 0.02 - 0.035 mol / L.

[0012] Furthermore, the concentration range of 2,5-dichloro-3,6-dihydroxy-p-benzoquinone in solution B is: 0.01 - 0.025 mol / L.

[0013] Furthermore, when washing with distilled water, the ratio range of the amount of distilled water used to the total volume of solution A and solution B is: 1 - 1.5.

[0014] The application of the above-mentioned coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O as an electrocatalyst in the electrocatalytic water oxidation reaction, comprising the following steps:

[0015] ​Step (1) Preparation of the working electrode: Take the dried coordination polymer sample in a mortar and grind it for 10 min. Weigh out 3 mg of the catalyst sample after grinding. Weigh out the catalyst sample after grinding and disperse it together with Nafion (5 wt.%) isopropanol dispersion in N,N'-dimethylformamide, where the volume ratio of Nafion (5 wt.%) isopropanol dispersion to N,N'-dimethylformamide is 1:24, and the concentration of the catalyst sample in the dispersion is 3 mg / mL. Ultrasonic for 30 min to obtain a dispersion. Drop 7 μL of the dispersion onto the calibrated glassy carbon electrode in two portions and allow it to dry naturally at room temperature.

[0016] Step (2): The OER electrochemical test based on a three-electrode system is carried out in 1.0 M KOH aqueous solution. The three-electrode system is: a glassy carbon (GC) electrode with a diameter of 3 mm as the working electrode, an Ag / AgCl (containing saturated KCl solution) electrode and a carbon rod electrode are used as the reference electrode and the counter electrode respectively. Based on the formula E RHE =E Ag / AgCl +(2.303×R×T×pH) / F + E ref , convert all the measured potentials to the potentials relative to RHE, where R is the gas constant, T is the absolute temperature, F is the Faraday constant, and E ref is the potential relative to the Ag / AgCl electrode. The OER overpotential (η) is calculated by the formula η = E RHE -E H2O .

[0017] The present invention has the following beneficial effects:

[0018] 1. The present invention uses a simple reaction to prepare a coordination polymer based on 2,5-dichloro-3,6-dihydroxybenzoquinone ligand as an electrolytic water catalyst. The preparation method of this coordination polymer has the advantages of simple synthesis steps and low cost, and has a certain prospect of large-scale application. The structure and purity of the material are characterized by X-ray single crystal diffraction and X-ray powder diffraction. The research results show that the coordination polymer presents a one-dimensional zigzag chain structure, and the chains are connected into a three-dimensional structure through weak hydrogen bond interactions, and the phase purity of the synthesized material is high.

[0019] 2. The present invention uses the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O as an electrocatalyst in the process of electrolytic water decomposition. This electrocatalyst shows good electrocatalytic oxygen evolution performance and stability. When obtaining 10 mA cm -2 ​The overpotential is only 378 mV at the current density, and the current density of this electrocatalyst remains stable overall during the 14-hour chronoamperometry test. After the chronoamperometry test, the overpotential increases by only 14 mV compared with that before the test. After 1000 cycles of CV tests, the overpotential at 10 mA cm -2 is only increased by 36 mV compared with that before the test, indicating that [CoCA(H 2 O) 2 n ‧nH 2 O has good stability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Figure 1 It is the structural unit diagram of the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O prepared in Example 1 of the present invention.

[0022] Figure 2 It is the one-dimensional structure diagram of the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O prepared in Example 1 of the present invention.

[0023] Figure 3 It is the X-ray powder diffraction pattern of the crystal of the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O prepared in Example 1 of the present invention.

[0024] Figure 4 It is the scanning electron microscope image of the crystal of the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O prepared in Example 1 of the present invention.

[0025] Figure 5 It is the coordination polymer [CoCA(H 2 O) 2 ​​​​​n ‧ nH 2 LSV polarization curve of O as an electrocatalyst.

[0026] Figure 6 Coordination polymer [CoCA(H 2 O) 2 n ‧ nH 2 Stability diagram of the electrocatalytic oxidation reaction test of O as an electrocatalyst.

[0027] Figure 7 Coordination polymer [CoCA(H 2 O) 2 n ‧ nH 2 LSV polarization curves before and after the chronoamperometry test of O as an electrocatalyst.

[0028] Figure 8 Coordination polymer [CoCA(H 2 O) 2 n ‧ nH 2 LSV polarization curves before and after 1000 - cycle CV test of O as an electrocatalyst. Detailed implementation manners

[0029] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the protection scope of the present invention.

[0030] The raw material 2,5 - dichloro - 3,6 - dihydroxy - p - benzoquinone used in the present invention is purchased from Shanghai Aladdin Biochemical Technology Co., Ltd., with a purity of 98%, and other raw materials are all commercially available products.

[0031] Example 1

[0032] This example is a preparation method of a coordination polymer based on a 2,5 - dichloro - 3,6 - dihydroxy - p - benzoquinone ligand, and the steps are as follows:

[0033] ​​​​Weigh 0.2 mmol of cobalt(II) acetate tetrahydrate and dissolve it in a mixed solution of 6 mL of methanol and 2 mL of water, denoted as solution A. Weigh 0.1 mmol of 2,5-dichloro-3,6-dihydroxy-p-benzoquinone and dissolve it in a mixed solution of 4 mL of methanol and 4 mL of water, denoted as solution B. Under stirring, add solution A dropwise to solution B. After the titration is completed, continue stirring for 30 min and then let it stand for 3 days. Filter and wash it 3 times with 20 mL of distilled water each time to obtain dark red block crystals.

[0034] 1) Structure identification

[0035] Place the dark red block crystals obtained in Example 1 on a glass slide and measure them on a Supernova type X-ray single crystal diffractometer. Use Mo-Kα radiation monochromatized by a graphite monochromator as the incident radiation source, collect diffraction points in a scanning mode, correct their coordinates and anisotropic parameters by the least squares method. The positions of hydrogen atoms are obtained by theoretical hydrogenation, and all calculations are carried out using the SHELXL-97 and SHELXL-97 program packages.

[0036] Combined with elemental analysis, thermogravimetric analysis, and data single crystal diffraction data analysis using Olex-2 software to determine the final molecular formula of the compound. The results show that: The structural formula of this material is [CoCA(H 2 O) 2 n ‧nH 2 O (where: n is a natural number from 1 to positive infinity), where H 2 CA is 2,5-dichloro-3,6-dihydroxy-p-benzoquinone, belonging to the monoclinic system, space group Cc, and the unit cell parameters are α = γ =90°, β =94.203(4)°, the unit cell volume V = 1687.11(11), Z = 4, where each metal cobalt has a six-coordinate structure and is coordinated with four oxygens from 2,5-dichloro-3,6-dihydroxy-p-benzoquinone and two oxygens from water molecules respectively. The adjacent Co metal centers are connected into a one-dimensional chain through ligand bridges. The structure diagram is drawn using Diamond software. Figure 1 This is the coordination environment diagram of the central metal Co of the [CoCA(H 2 O) 2 n ‧nH 2 O coordination polymer prepared in this example. Figure 2 This is the one-dimensional chain structure diagram of the [CoCA(H 2 O) 2 n ‧nH 2 O coordination polymer prepared in this example.​​​

[0037] 2) Purity and Morphology Characterization

[0038] Figure 3 For the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O crystal prepared in this example, the X-ray powder diffraction pattern. The prepared coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O crystal's powder diffraction pattern is consistent with the X-ray pattern simulated from the crystal data, indicating that the synthesized material has a very high purity.

[0039] Figure 4 For the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O crystal prepared in this example, the scanning electron micrograph. From the scanning electron microscope images of the prepared coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O, it can be seen that the coordination polymer has a dispersed two-dimensional nanosheet morphology.

[0040] Example 2

[0041] This example is a preparation method of a coordination polymer based on 2,5-dichloro-3,6-dihydroxybenzoquinone ligand, and the steps are as follows:

[0042] Weigh 0.3 mmol of cobalt chloride hexahydrate and dissolve it in a mixed solution of 9 mL of methanol and 3 mL of water, denoted as solution A. Weigh 0.1 mmol of 2,5-dichloro-3,6-dihydroxybenzoquinone and dissolve it in a mixed solution of 3 mL of methanol and 3 mL of water, denoted as solution B. Under stirring, add solution A dropwise to solution B. After the titration is completed, continue stirring for 30 min and then let it stand for 4 days. Filter, and wash it 3 times with 20 mL of distilled water respectively to obtain dark red block crystals.

[0043] Example 3

[0044] This example is a preparation method of a coordination polymer based on 2,5-dichloro-3,6-dihydroxybenzoquinone ligand, and the steps are as follows:

[0045] ​​​​Weigh 0.5 mmol of cobalt(II) acetate tetrahydrate and dissolve it in a mixed solution of 12 mL of methanol and 4 mL of water, denoted as solution A. Weigh 0.25 mmol of 2,5-dichloro-3,6-dihydroxy-p-benzoquinone and dissolve it in a mixed solution of 6 mL of methanol and 6 mL of water, denoted as solution B. Under stirring, add solution A dropwise to solution B. After the titration is completed, continue stirring for 30 min and then let it stand for 6 days. Filter and wash it three times with 30 mL of distilled water respectively to obtain dark red blocky crystals.

[0046] Example 4

[0047] This example is a preparation method of a coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand, and the steps are as follows:

[0048] Weigh 0.35 mmol of cobalt(II) chloride hexahydrate and dissolve it in a mixed solution of 7.5 mL of methanol and 2.5 mL of water, denoted as solution A. Weigh 0.12 mmol of 2,5-dichloro-3,6-dihydroxy-p-benzoquinone and dissolve it in a mixed solution of 5 mL of methanol and 5 mL of water, denoted as solution B. Under stirring, add solution A dropwise to solution B. After the titration is completed, continue stirring for 20 min and then let it stand for 5 days. Filter and wash it three times with 20 mL of distilled water respectively to obtain dark red blocky crystals.

[0049] Example 5

[0050] This example is a preparation method of a coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand, and the steps are as follows:

[0051] Weigh 0.5 mmol of cobalt(II) acetate tetrahydrate and dissolve it in a mixed solution of 11.25 mL of methanol and 3.75 mL of water, denoted as solution A. Weigh 0.25 mmol of 2,5-dichloro-3,6-dihydroxy-p-benzoquinone and dissolve it in a mixed solution of 5 mL of methanol and 5 mL of water, denoted as solution B. Under stirring, add solution A dropwise to solution B. After the titration is completed, continue stirring for 45 min and then let it stand for 7 days. Filter and wash it three times with 35 mL of distilled water respectively to obtain dark red blocky crystals.

[0052] Application Example

[0053] This application example is about the application of the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O as an electrocatalyst in the electrocatalytic water oxidation reaction, and the steps are as follows:

[0054] ​Step (1): Preparation of the working electrode: Take the dried coordination polymer sample in a mortar and grind it for 10 min. Weigh out 3 mg of the ground catalyst sample. Weigh out the ground catalyst sample and Nafion (5 wt.%) isopropanol dispersion and disperse them together in N,N'-dimethylformamide, where the volume ratio of Nafion (5 wt.%) isopropanol dispersion to N,N'-dimethylformamide is 1:24, and the concentration of the catalyst sample in the dispersion is 3 mg / mL. Ultrasonic for 30 min to obtain a dispersion. Drop 7 μL of the dispersion onto the calibrated glassy carbon electrode in two portions and let it dry naturally at room temperature.

[0055] Step (2): The OER electrochemical test based on the three-electrode system is carried out in 1.0 M KOH aqueous solution. The three-electrode system is: a glassy carbon (GC) electrode with a diameter of 3 mm is used as the working electrode, and an Ag / AgCl (containing saturated KCl solution) electrode and a carbon rod electrode are used as the reference electrode and the counter electrode respectively. Based on the formula E RHE =E Ag / AgCl + (2.303×R×T×pH) / F + E ref , convert all the measured potentials to the potentials relative to RHE, where R is the gas constant, T is the absolute temperature, F is the Faraday constant, and E ref is the potential relative to the Ag / AgCl electrode. The OER overpotential (η) is calculated by the formula η = E RHE - E H2O .

[0056] The coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O is used for the performance test of the electrocatalyst

[0057] Figure 5 This is the LSV polarization curve diagram of the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O prepared in Example 1 of the present invention as an electrocatalyst. At a current density of 10 mA cm -2 , the oxygen evolution overpotential of this coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O is 378 mV.

[0058] Figure 6 This is the coordination polymer [CoCA(H 2 O) 2 ​​​​n ‧nH 2 O as the stability diagram of the electrocatalytic oxidation reaction of the electrocatalyst. Through chronoamperometry testing, we evaluated the electrocatalytic stability of the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O. The current density of the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O remained generally stable during the 14 h test time.

[0059] Figure 7 For the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O prepared in Example 1 of the present invention as the LSV polarization curve before and after the chronoamperometry test. The OER performance of the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O before and after the chronoamperometry test was compared. It was found that after 14 h of testing, the overpotential of the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O at 10 mA cm -2 increased by 14 mV compared to before the test.

[0060] Figure 8 For the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O prepared in Example 1 of the present invention as the LSV polarization curve before and after 1000 cycles of CV testing. The coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O was subjected to 1000 cycles of CV testing. The overpotential of the polarization curve after the test increased by only 36 mV compared to before the test. The difference in overpotential before and after the chronoamperometry test and the CV test was not significant, indicating that [CoCA(H 2 O) 2 n ‧nH 2 O has good durability in catalytic performance.

[0061] ​​​​​​​​In summary, the present invention provides a coordination polymer synthesized based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand for use as an electrolytic water catalyst. The catalyst is used for OER performance testing under alkaline conditions. The preparation process is simple, and it exhibits a low overpotential and good stability during the catalytic process.

[0062] The foregoing is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included within the protection scope of the present invention.

Claims

1. A preparation method of a coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand, characterized in that: Dissolve the cobalt salt in the mixed solution I, denoted as solution A; separately dissolve 2,5-dichloro-3,6-dihydroxy-p-benzoquinone in the mixed solution II, denoted as solution B; then, under stirring, drop solution A into solution B. After the dropping is completed, continue stirring, and then let it stand. Filter and wash to obtain the coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O, where n is a natural number from 1 to positive infinity;​ The coordination polymer [CoCA(H 2 O) 2 n ‧nH 2 O uses 2,5-dichloro-3,6-dihydroxy-p-benzoquinone as the organic ligand; it belongs to the monoclinic system and the space group Cc , the unit cell parameters are α = γ = 90°, β = 94.203(4)°, the unit cell volume V = 1687.11(11), Z = 4, where each cobalt metal has a six-coordinate structure, coordinated with four oxygens from 2,5-dichloro-3,6-dihydroxy-p-benzoquinone and two oxygens from water molecules respectively, and adjacent Co metal centers are connected into a one-dimensional chain through ligand bridges;​ The molar ratio of the cobalt salt to 2,5-dichloro-3,6-dihydroxy-p-benzoquinone is (2-3):

1.

2. The preparation method of the coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand according to claim 1, characterized in that: The cobalt salt is cobalt acetate tetrahydrate or cobalt chloride hexahydrate.

3. The preparation method of the coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand according to claim 2, characterized in that: The mixed solution I is a mixed solution of methanol and water, and the volume ratio of methanol to water is 3:1; the concentration of the cobalt salt in solution A is 0.02-0.035 mol / L.

4. The preparation method of the coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand according to claim 3, characterized in that: The mixed solution II is a mixed solution of methanol and water, and the volume ratio of methanol to water is 1:1; the concentration of 2,5-dichloro-3,6-dihydroxy-p-benzoquinone in solution B is 0.01-0.025 mol / L.

5. The preparation method of the coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand according to claim 4, characterized in that: The time for continued stirring is 20-45 min, and the standing time is 3-7 days.

6. The preparation method of the coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand according to any one of claims 1-5, characterized in that: The washing solution is distilled water, and the amount of distilled water used is 1-1.5 times the total volume of solution A and solution B, and the number of washing times > 2 times.

7. The application of the coordination polymer based on 2,5-dichloro-3,6-dihydroxy-p-benzoquinone ligand as claimed in claim 1 in the electrocatalytic water decomposition oxidation reaction, characterized in that, The steps are as follows: (1) Preparation of the working electrode: Take the coordination polymer described in claim 1 and grind it in a mortar for 10 min, then take 3 mg and disperse it together with 5 wt.% Nafion isopropanol dispersion in N,N'-dimethylformamide. The volume ratio of 5 wt.% Nafion isopropanol dispersion to N,N'-dimethylformamide is 1:24, and the concentration of the coordination polymer in the dispersion is 3 mg / mL; ultrasonic for 30 min to obtain a dispersion; drop 7 μL of the dispersion onto the calibrated glassy carbon electrode in two times and air-dry it at room temperature to obtain the working electrode; (2) OER electrochemical test based on a three-electrode system: The three-electrode system is: use the glassy carbon electrode with a diameter of 3 mm obtained in step (1) as the working electrode, an Ag / AgCl electrode containing saturated KCl solution as the reference electrode, and a carbon rod electrode as the counter electrode, and use 1.0 M KOH aqueous solution as the electrolyte to catalyze water decomposition.

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