An electrocatalytic electrode plate, its preparation method and application

Abstract

The present invention discloses an electrocatalytic electrode plate, which comprises a graphite plate, and a polymer layer is arranged on the surface of the graphite plate. The polymer layer is made of polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione material; the preparation method of polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione is as follows: the graphite plate serves as the working electrode and the counter electrode, the non-mercury ion electrode serves as the reference electrode, and the acetonitrile solution containing 0.5-10 mM of benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.05-0.2 M of tetrabutylammonium perchlorate is used as the reaction solution. Oxidative electro-polymerization is carried out on the surface of the working electrode and then washed with acetonitrile and ultrapure water. The present invention also discloses the preparation method and application of the electrocatalytic electrode plate. The preparation period of the present invention is short, economical and efficient; precious metals are not required for the preparation of the catalyst, and there are no high-temperature and high-pressure operation steps and no special equipment is required during the preparation process.

Description

Technical Field

[0001] The present invention belongs to the field of electrocatalytic degradation of organic compounds, and specifically relates to an electrocatalytic electrode plate, a preparation method thereof, and an application thereof. Background Art

[0002] Electrochemical degradation of pollutants is a commonly used advanced treatment method in water treatment. According to the action principle, it is divided into directly oxidizing and reducing pollutants and indirectly cracking pollutants by electrocatalytically generating free radicals. Directly oxidizing and reducing pollutants requires design according to the redox characteristics of pollutants, and often has poor effects due to the low electrochemical activity of target pollutants. In contrast, the free radicals generated by indirectly cracking pollutants by electrocatalytically generating free radicals have extremely high oxidation potentials (such as ·OH≈2.8 V), can crack most pollutants, and are more flexible in application.

[0003] Electro-Fenton is one of the most widely used methods, but the classical system is troubled by pH limitation (acidic) and iron sludge problems. Green electro-Fenton requires the electrode to have the ability to in-situ generate H2O2 and catalyze the generation of free radicals such as ·OH from H2O2. The in-situ generation of H2O2 relies on the 2-electron reduction reaction of oxygen in water. However, most of the reported 2-electron oxygen reduction reactions in the literature are carried out under acidic (Jia et al., Nature Catalysis, 2019, 2: 688-695; Wang et al., Nature Catalysis, 2021, 4: 753-762) or alkaline (Chen et al., Nature Communications, 2020, 11: 4173, Chang et al., Nature Communications, 2020, 11: 2178) conditions. When used in the field of water treatment, the electrodes used need to maintain good performance under near-neutral conditions.

[0004] Most catalysts are synthesized by hydrothermal method or calcination method to obtain powder catalyst materials, and then loaded on the electrode surface by methods such as drop coating and spin coating. This method has the following disadvantages: (1) The process is complex and the operation time is long; (2) There is a risk of catalyst shedding during long-term use; (3) The catalyst loading affects the conductivity of the electrode.

[0005] Chinese Patent with application number 200610007233.X discloses a method for treating high-difficulty organic wastewater with free radicals and an electrocatalytic reaction device for implementing the method. A free radical chain reaction is carried out with various refractory organic compounds in an electrocatalytic high-pressure reaction kettle to efficiently decompose organic compounds. However, it requires external addition of oxygen stabilizers and other additives such as ferrous sulfate and sodium sulfate, and the reaction conditions are harsh, requiring special equipment.

[0006] Existing catalysts are mostly synthesized in powder form. To prepare electrode materials, specific loading steps are required. The process is complex, the preparation cycle is long, and the electrical conductivity of the materials is difficult to guarantee. Activating hydrogen peroxide to produce hydroxyl radicals in the existing system requires the addition of ferrous ions and an acidic pH, which limits its application in actual sewage treatment. Existing materials cannot possess both the ability to efficiently produce hydrogen peroxide under neutral conditions and activate hydrogen peroxide to produce free radicals. Summary of the Invention

[0007] Object of the Invention: In order to overcome the deficiencies in the prior art, the object of the present invention is to provide an electrocatalytic electrode plate prepared by one-step electro-polymerization; another object of the present invention is to provide a preparation method of an electrocatalytic electrode plate with a short preparation cycle, economy and high efficiency. Another object of the present invention is to provide an application of the electrocatalytic electrode plate in the electrocatalytic degradation of azithromycin.

[0008] Technical Solution: An electrocatalytic electrode plate according to the present invention includes a graphite plate, and a polymer layer is provided on the surface of the graphite plate. The polymer layer is made of polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione material; the preparation method of the polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione is as follows: using the graphite plate as the working electrode and the counter electrode, using a non-mercury ion electrode as the reference electrode, and using an acetonitrile solution containing 0.5 - 10 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.05 - 0.2 M tetrabutylammonium perchlorate as the reaction solution, and performing oxidative electro-polymerization on the surface of the working electrode by cyclic voltammetry or potentiostatic method. After the polymerization is completed, it is washed with acetonitrile and ultrapure water to remove the residual organic solution on the electrode surface, and thus polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione is obtained.

[0009] Further, the thickness of the polymer layer is 50 - 200 nm.

[0010] A preparation method of an electrocatalytic electrode plate according to the present invention includes the following steps:

[0011] Step 1, cleaning: cleaning the graphite plate;

[0012] Step 2, preparing a non-aqueous reference electrode: taking a non-mercury ion electrode as the reference electrode, and the filling solution of the non-mercury ion electrode is an acetonitrile solution of 0.05 - 0.2 M tetrabutylammonium perchlorate;

[0013] Step 3, Electro-polymerization: Using the cleaned graphite plate as the working electrode and the counter electrode, an acetonitrile solution containing 0.5 - 10 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.05 - 0.2 M tetrabutylammonium perchlorate as the reaction solution, perform oxidative electro-polymerization on the surface of the working electrode by cyclic voltammetry scanning or potentiostatic method. After the polymerization is completed, wash it with acetonitrile and ultrapure water to obtain the electrocatalytic plate.

[0014] Further, in Step 3, the cyclic voltammetry scanning method is as follows: Perform cyclic voltammetry scanning for 1 - 20 cycles at a scanning rate of 10 - 100 mV / s within a potential window of 0 - 2.3 V. The cyclic voltammetry scanning method is preferably: Perform cyclic voltammetry scanning for 5 cycles at a scanning rate of 50 mV / s within a potential window of 0.5 - 2.3 V. If the upper limit of the scanning voltage is too low, benzo[1,2-b:4,5-b']dithiophene-4,8-dione cannot be polymerized; if the scanning rate is too fast, the polymerization will be insufficient, and if the scanning rate is too slow, the polymerized layer will be too dense, affecting mass transfer and electron transfer.

[0015] Further, in Step 3, the potentiostatic method is as follows: Apply a constant potential of 2.0 - 2.5 V to the working electrode for 1 - 60 seconds. The potentiostatic method is preferably: Apply a constant potential of 2.3 V to the working electrode for 10 seconds. The potentiostatic method is faster, the structural stratification of the cyclic voltammetry is better, and the repeatability of multiple preparations is better. If the constant potential is less than 2.0 V, polymerization cannot start.

[0016] Further, in Step 3, the reaction solution is an acetonitrile solution containing 5 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.1 M tetrabutylammonium perchlorate. After the electrocatalytic plate is prepared, soak it in water for later use.

[0017] Application of the electrocatalytic plate described in the present invention as a cathode in the electrocatalytic degradation of azithromycin.

[0018] Further, using an iridium oxide / ruthenium oxide / platinum sheet / graphite composite material as the anode and a silver / silver chloride electrode as the reference electrode, the electrode solution of the reference electrode is 3 M or saturated potassium chloride, and perform electrocatalytic degradation at a constant potential of -0.7 to -1.0 V in an oxygenated aqueous solution. The constant potential is preferably -0.7 V.

[0019] Reaction principle: The electro-polymerization preparation method of the electrocatalytic electrode plate is based on the electrochemical oxidative polymerization of benzo[1,2-b:4,5-b']dithiophene-4,8-dione on the electrode surface. When thiophene compounds are applied with an oxidation potential, the 2nd and 5th positions of their thiophene rings tend to lose electrons, form thiophene radicals and react with other thiophene molecules to polymerize into polythiophene compounds on the electrode surface. The obtained polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode has an ordered assembly compared to p-benzoquinone in solution, and electron transfer is more likely to occur. Moreover, the ortho and meta positions of p-benzoquinone are blocked by thiophene rings, avoiding the occurrence of Michael electrophilic addition reactions. In the case of the presence of oxygen in the solution, when the polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode is used as the cathode, an oxygen reduction reaction occurs on the electrode surface, and the generated hydrogen peroxide is further catalyzed by the polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode to generate •OH, 1 O2 and other free radicals for degrading pollutants.

[0020] In order to solve the problems of the long preparation period of the catalyst and the limitation of the pH of the electro-Fenton system, the present invention attempts to electro-polymerize the electrocatalytic electrode plate by a one-step method to simultaneously reduce oxygen to generate hydrogen peroxide and catalyze hydrogen peroxide to generate free radicals for cracking pollutants, so as to achieve the economical and efficient preparation of the electrocatalytic electrode plate and the efficient removal of pollutants in sewage using this electrode.

[0021] Beneficial effects: Compared with the prior art, the present invention has the following significant features:

[0022] 1. One-step polymerization, rapid preparation, about 10 minutes, short preparation period, pH not limited, economical and efficient;

[0023] 2. The preparation of the catalyst does not require precious metals, the raw materials are simple and easy to obtain, there are no high-temperature and high-pressure operation steps in the preparation process, and no special equipment is required, safe and easy to promote;

[0024] 3. The obtained electrode plate can perform electrocatalysis under nearly neutral conditions and is suitable for sewage systems;

[0025] 4. No external H2O2 is required. The electrode plate generates H2O2 and catalyzes H2O2 to generate free radicals simultaneously during the catalytic process. The system is simple and has wide applicability. Description of the drawings

[0026] Figure 1 is the preparation schematic diagram of the present invention;

[0027] Figure 2 are the linear sweep voltammetry results of the disk electrode of the rotating ring-disk electrode loaded with polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione and a common graphite electrode respectively;

[0028] Figure 3 is the current-time graph of the present invention during the catalytic process at 50 mL / min O2 and -1.0 V voltage;

[0029] Figure 4 is the degradation curve graph of azithromycin by the present invention and a common graphite electrode at 50 mL / min O2 and -1.0 V voltage;

[0030] Figure 5 is the hydrogen peroxide concentration-time graph of the present invention and a common graphite electrode at 50 mL / min O2 and -1.0 V voltage. Detailed implementation manners

[0031] In the following examples, the non-mercury ion electrode used is the Shanghai Chenhua CHI112 non-aqueous Ag / Ag + (silver / silver ion) reference electrode, and the filling solution can be filled as needed.

[0032] Example 1

[0033] A preparation method of an electrocatalytic electrode plate includes the following steps:

[0034] Step 1, cleaning: Clean the graphite plate successively with 0.1 M sulfuric acid, 0.1 M sodium hydroxide, and ethanol;

[0035] Step 2, preparing the non-aqueous reference electrode 3: Take the non-mercury ion electrode as the reference electrode 3, and replace the filling solution of the non-mercury ion electrode with an acetonitrile solution of 0.1 M tetrabutylammonium perchlorate;

[0036] Step 3, electro-polymerization: As Figure 1 , use the cleaned graphite plate as the working electrode 1 and the counter electrode 2 respectively, and use the non-mercury ion electrode with the replaced filling solution obtained in Step 2 as the reference electrode 3 to perform scanning cyclic voltammetry oxidative electro-polymerization. The reaction solution is an acetonitrile solution containing 0.5 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.1 M tetrabutylammonium perchlorate. Scan 10 cycles at a scanning rate of 100 mV / s within the potential window of 1.0~2.3 V. After the polymerization is completed, wash with acetonitrile and ultrapure water to obtain a polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode, and then soak it in water for later use.

[0037] Example 2

[0038] A preparation method of an electrocatalytic electrode plate includes the following steps:

[0039] Step 1, cleaning: Clean the graphite plate successively with 0.1 M sulfuric acid, 0.1 M sodium hydroxide, and ethanol;

[0040] Step 2, Prepare a non-aqueous reference electrode 3: Use a non-mercury ion electrode as the reference electrode 3, and replace the filling solution of the non-mercury ion electrode with an acetonitrile solution of 0.1 M tetrabutylammonium perchlorate;

[0041] Step 3, Electro-polymerization: Use the cleaned graphite plate as the working electrode 1 and the counter electrode 2 respectively, and perform cyclic voltammetry oxidation electro-polymerization with the non-mercury ion electrode with the replaced filling solution obtained in Step 2 as the reference electrode 3. The reaction solution is an acetonitrile solution containing 10 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.1 M tetrabutylammonium perchlorate. Scan 1 cycle at a scanning rate of 10 mV / s within a potential window of 0 to 2.3 V. After polymerization, wash with acetonitrile and ultrapure water to obtain a polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode, and then soak it in water for later use.

[0042] Example 3

[0043] A method for preparing an electrocatalytic electrode plate includes the following steps:

[0044] Step 1, Cleaning: Clean the graphite plate successively with 0.1 M sulfuric acid, 0.1 M sodium hydroxide, and ethanol;

[0045] Step 2, Prepare a non-aqueous reference electrode 3: Use a non-mercury ion electrode as the reference electrode 3, and replace the filling solution of the non-mercury ion electrode with an acetonitrile solution of 0.1 M tetrabutylammonium perchlorate;

[0046] Step 3, Electro-polymerization: Use the cleaned graphite plate as the working electrode 1 and the counter electrode 2 respectively, and perform constant potential oxidation electro-polymerization with the non-mercury ion electrode with the replaced filling solution obtained in Step 2 as the reference electrode 3. The reaction solution is an acetonitrile solution containing 5 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.1 M tetrabutylammonium perchlorate. Apply a constant potential of 2.3 V to the working electrode 1 for 10 seconds. After polymerization, wash with acetonitrile and ultrapure water to obtain a polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode, and then soak it in water for later use.

[0047] Example 4

[0048] A method for preparing an electrocatalytic electrode plate includes the following steps:

[0049] Step 1, Cleaning: Clean the graphite plate successively with 0.1 M sulfuric acid, 0.1 M sodium hydroxide, and ethanol;

[0050] Step 2, Prepare a non-aqueous reference electrode 3: Use a non-mercury ion electrode as the reference electrode 3, and replace the filling solution of the non-mercury ion electrode with an acetonitrile solution of 0.1 M tetrabutylammonium perchlorate;

[0051] Step 3, Electro-polymerization: Using the cleaned graphite plates as the working electrode 1 and the counter electrode 2 respectively, and using the non-mercury ion electrode with the replenished filling solution obtained in Step 2 as the reference electrode 3, perform cyclic voltammetry oxidation electro-polymerization by scanning. The reaction solution is an acetonitrile solution containing 5 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.1 M tetrabutylammonium perchlorate. Scan 5 cycles at a scanning rate of 50 mV / s within a potential window of 0.5 - 2.3 V. After polymerization is completed, wash with acetonitrile and ultrapure water to obtain a polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode, and then soak it in water for later use.

[0052] Example 5

[0053] A method for preparing an electrocatalytic electrode plate includes the following steps:

[0054] Step 1, Cleaning: Clean the graphite plates successively with 0.1 M sulfuric acid, 0.1 M sodium hydroxide, and ethanol;

[0055] Step 2, Prepare a non-aqueous reference electrode 3: Take a non-mercury ion electrode as the reference electrode 3, and replace the filling solution of the non-mercury ion electrode with an acetonitrile solution of 0.05 M tetrabutylammonium perchlorate;

[0056] Step 3, Electro-polymerization: Using the cleaned graphite plates as the working electrode 1 and the counter electrode 2 respectively, and using the non-mercury ion electrode with the replenished filling solution obtained in Step 2 as the reference electrode 3, perform cyclic voltammetry oxidation electro-polymerization by scanning. The reaction solution is an acetonitrile solution containing 2 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.05 M tetrabutylammonium perchlorate. Scan 20 cycles at a scanning rate of 20 mV / s within a potential window of 1.0 - 2.3 V. After polymerization is completed, wash with acetonitrile and ultrapure water to obtain a polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode, and then soak it in water for later use.

[0057] Example 6

[0058] A method for preparing an electrocatalytic electrode plate includes the following steps:

[0059] Step 1, Cleaning: Clean the graphite plates successively with 0.1 M sulfuric acid, 0.1 M sodium hydroxide, and ethanol;

[0060] Step 2, Prepare a non-aqueous reference electrode 3: Take a non-mercury ion electrode as the reference electrode 3, and replace the filling solution of the non-mercury ion electrode with an acetonitrile solution of 0.2 M tetrabutylammonium perchlorate;

[0061] Step 3, Electro-polymerization: Using the cleaned graphite plates as the working electrode 1 and the counter electrode 2 respectively, and the non-mercury ion electrode with the replaced filling solution obtained in Step 2 as the reference electrode 3, perform cyclic voltammetry oxidation electro-polymerization. The reaction solution is an acetonitrile solution containing 8 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.2 M tetrabutylammonium perchlorate. Scan 15 cycles at a scan rate of 80 mV / s within a potential window of 0.5 - 2.3 V. After polymerization, wash with acetonitrile and ultrapure water to obtain a polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode, and then soak it in water for later use.

[0062] Example 7

[0063] A method for preparing an electrocatalytic electrode plate includes the following steps:

[0064] Step 1, Cleaning: Clean the graphite plates successively with 0.1 M sulfuric acid, 0.1 M sodium hydroxide, and ethanol;

[0065] Step 2, Prepare a non-aqueous reference electrode 3: Take a non-mercury ion electrode as the reference electrode 3, and replace the filling solution of the non-mercury ion electrode with an acetonitrile solution of 0.05 M tetrabutylammonium perchlorate;

[0066] Step 3, Electro-polymerization: Using the cleaned graphite plates as the working electrode 1 and the counter electrode 2 respectively, and the non-mercury ion electrode with the replaced filling solution obtained in Step 2 as the reference electrode 3, perform constant potential oxidation electro-polymerization. The reaction solution is an acetonitrile solution containing 3 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.05 M tetrabutylammonium perchlorate. Apply a constant potential of 2.0 V to the working electrode 1 for 60 seconds. After polymerization, wash with acetonitrile and ultrapure water to obtain a polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode, and then soak it in water for later use.

[0067] Example 8

[0068] A method for preparing an electrocatalytic electrode plate includes the following steps:

[0069] Step 1, Cleaning: Clean the graphite plates successively with 0.1 M sulfuric acid, 0.1 M sodium hydroxide, and ethanol;

[0070] Step 2, Prepare a non-aqueous reference electrode 3: Take a non-mercury ion electrode as the reference electrode 3, and replace the filling solution of the non-mercury ion electrode with an acetonitrile solution of 0.2 M tetrabutylammonium perchlorate;

[0071] Step 3, Electro-polymerization: Using the cleaned graphite plates as the working electrode 1 and the counter electrode 2 respectively, and using the non-mercury ion electrode with the replaced filling solution obtained in Step 2 as the reference electrode 3, perform potentiostatic oxidation electro-polymerization. The reaction solution is an acetonitrile solution containing 7 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.2 M tetrabutylammonium perchlorate. Apply a constant potential of 2.5 V to the working electrode 1 for 1 second. After the polymerization is completed, wash with acetonitrile and ultrapure water to obtain a polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode, and then soak it in water for later use.

[0072] In the above examples, when the polymerization voltage is less than 2.0 V, the polymerization is slow and cannot occur. At 2.0 - 2.2 V, the oxidation peak of Bth-BQ is very weak and the polymerization efficiency is low; while when the voltage upper limit is higher than 2.3 V, the current decreases significantly as the polymerization proceeds, indicating that over-oxidation leads to poor conductivity of the polymer at this time. Therefore, Example 3 is the optimal example in the potentiostatic method, and Example 4 is the optimal example in the cyclic voltammetry method.

[0073] Example 9

[0074] This example is an electrochemical characterization, reflecting the catalytic ability of the polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode. The rotating ring-disk electrode is a special test electrode, whose structure is a glassy carbon disk in the middle and a platinum ring on the outer circle, which are controlled by different circuits respectively. The polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione material is polymerized on the middle disk.

[0075] A preparation method of a rotating ring-disk electrode with polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione loaded on a disk electrode, comprising the following steps:

[0076] Step 1, Cleaning: Polish the rotating ring-disk electrode successively with 1.0, 0.3, and 0.05 μm α-Al2O3, and then ultrasonically clean it successively with acid, alkali, and organic solution;

[0077] Step 2, Prepare a non-aqueous reference electrode 3: Take a non-mercury ion electrode as the reference electrode 3, and replace the filling solution with an acetonitrile solution of 0.1 M tetrabutylammonium perchlorate;

[0078] Step 3, Electro-polymerization: Using the cleaned rotating ring-disk electrode as the working electrode 1, a platinum sheet as the counter electrode 2, and a non-aqueous Ag electrode as the reference electrode, the reaction solution is an acetonitrile solution containing 5 mM benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.1 M tetrabutylammonium perchlorate. Cyclic voltammetry is performed 5 times at a scan rate of 50 mV / s within a potential window of 0.5 - 2.3 V to complete the electro-polymerization. After the polymerization is completed, it is washed with acetonitrile and ultrapure water to obtain a rotating ring-disk electrode with polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione on the disk and a platinum ring on the outer ring.

[0079] In an oxygen-saturated 0.1 M PBS solution (pH = 7.2 - 7.4), using the above-mentioned rotating ring-disk electrode as the working electrode, a platinum sheet as the counter electrode, and a silver / silver chloride electrode as the reference electrode, linear sweep voltammetry (LSV) test is carried out at a rotation speed of 1600 rpm. The scanning range is from 0.5 V to -1.2 V, the scanning speed is 5 mV / s, and the ring voltage is set to 1.2 V (vs.RHE). In addition, the same test is carried out with a polished rotating ring-disk electrode.

[0080] The test results are as Figure 2 shown: The disk current reflects the reaction current occurring at a certain potential of the electrode, and the ring current reflects the concentration of hydrogen peroxide generated by the reaction on the disk. Compared with ordinary graphite, the ring-disk electrode loaded with polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione catalyst exhibits a larger reaction current and hydrogen peroxide production at a more positive potential, and its catalytic performance is good.

[0081] Application Example 1

[0082] Taking the polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode prepared in Example 4 as the cathode, a graphite sheet as the anode, and a silver / silver chloride as the reference electrode 3, the electrode solution of the reference electrode 3 is 3M potassium chloride, and an electrocatalytic experiment is carried out in a 0.1 M Na2SO4 solution containing 5 mM azithromycin. The oxygen exposure amount is controlled at 10 mL / min and the water temperature is controlled at 30 degrees Celsius. A voltage of -0.7 V is applied to the cathode, and 92% of the pollutant azithromycin is removed within 6 hours, which is 60% higher than the condition of exposing to N2 and 10% higher than the non-aeration condition.

[0083] 3M potassium chloride can be replaced by saturated potassium chloride. The graphite sheet can be replaced by any one of iridium oxide, ruthenium oxide, and platinum sheet.

[0084] Application Example 2

[0085] Taking the polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode prepared in Example 4 as the cathode, ruthenium oxide as the anode, and silver / silver chloride as the reference electrode 3, with the electrode solution of the reference electrode 3 being 3 M potassium chloride, an electrocatalytic experiment was carried out in a 0.1 M Na2SO4 solution containing 5 mM azithromycin. The oxygen exposure was controlled at 50 mL / min and the water temperature was controlled at 30 °C. A voltage of -0.7 V was applied to the cathode, and 94% of the pollutant azithromycin was removed within 6 hours, which was 45% higher than that of the graphite electrode.

[0086] Application Example 3

[0087] Taking the polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode prepared in Example 4 as the cathode, iridium oxide as the anode, and silver / silver chloride as the reference electrode 3, with the electrode solution of the reference electrode 3 being 3 M potassium chloride, an electrocatalytic experiment was carried out in a 0.1 M Na2SO4 solution containing 5 mM azithromycin. The oxygen exposure was controlled at 50 mL / min and the water temperature was controlled at 30 °C. A voltage of -0.8 V was applied to the cathode, and 93% of the pollutant azithromycin was removed within 6 hours, which was 30% higher than that of the graphite electrode.

[0088] Application Example 4

[0089] Taking the polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione electrode prepared in Example 4 as the cathode, a platinum sheet as the anode, and silver / silver chloride as the reference electrode 3, with the electrode solution of the reference electrode 3 being 3 M potassium chloride, an electrocatalytic experiment was carried out in a 0.1 M Na2SO4 solution containing 5 mM azithromycin. The oxygen exposure was controlled at 50 mL / min and the water temperature was controlled at 30 °C. A voltage of -1.0 V was applied to the cathode, and its current-time curve is as Figure 3 shown. During the electrocatalytic process, the current stabilized at about 30 mA, and the current density was 1.8 mA / cm 2 . The degradation curve of the pollutant azithromycin within 6 hours is as Figure 4 shown, and the hydrogen peroxide production is as Figure 5 shown. After 2 hours of electrocatalysis, the concentration stabilized at about 9 mg / L.

[0090] In the above application examples, the degradation conditions in Application Example 2 are the optimal process parameters.

[0091] Comparative Example 2

[0092] The remaining steps of this comparative example are the same as those of Example 4, except that: benzo[1,2-b:4,5-b']dithiophene-4,8-dione was replaced with benzo[1,2-b:4,5-b']dithiophene. According to the degradation conditions of Application Example 3, 30% of the pollutant azithromycin was removed within 6 hours.

[0093] Comparative Example 3

[0094] The remaining steps of this comparative example are the same as those of Example 4, except that cyclic voltammetry scanning electropolymerization is carried out in the potential range of 0.5 - 1.5 V. According to the degradation conditions of Application Example 3, 62% of the pollutant azithromycin is removed within 6 hours.

Claims

1. An electrocatalytic electrode plate, characterized in that: It includes a graphite plate, on the surface of which a polymer layer is provided, and the polymer layer is made of polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione material; the preparation method of the polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione is as follows: using the graphite plate as the working electrode (1) and the counter electrode (2), using a non-mercury ion electrode as the reference electrode (3), and using an acetonitrile solution containing 0.5 - 10 mM of benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.05 - 0.2 M of tetrabutylammonium perchlorate as the reaction solution, and performing oxidative electropolymerization on the surface of the working electrode (1) by cyclic voltammetry or potentiostatic method. After the polymerization is completed, it is washed with acetonitrile and ultrapure water to obtain polybenzo[1,2-b:4,5-b']dithiophene-4,8-dione.

2. The electrocatalytic electrode plate according to claim 1, wherein: The thickness of the polymer layer is 50 - 200 nm.

3. A method for preparing an electrocatalytic electrode plate, characterized in that, It includes the following steps: Step 1, cleaning the graphite plate; Step 2, taking a non-mercury ion electrode as the reference electrode (3), and the filling solution of the non-mercury ion electrode is an acetonitrile solution containing 0.05 - 0.2 M of tetrabutylammonium perchlorate; Step 3, using the cleaned graphite plate as the working electrode (1) and the counter electrode (2), and using an acetonitrile solution containing 0.5 - 10 mM of benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.05 - 0.2 M of tetrabutylammonium perchlorate as the reaction solution, and performing oxidative electropolymerization on the surface of the working electrode (1) by cyclic voltammetry or potentiostatic method. After the polymerization is completed, it is washed with acetonitrile and ultrapure water to obtain an electrocatalytic electrode plate.

4. The preparation method of an electrocatalytic electrode plate according to claim 3, wherein: In Step 3, the cyclic voltammetry method is: performing cyclic voltammetry for 1 - 20 cycles at a scan rate of 10 - 100 mV / s within a potential window of 0 - 2.3 V.

5. The preparation method of an electrocatalytic electrode plate according to claim 4, characterized in that: The cyclic voltammetry method is: performing cyclic voltammetry for 5 cycles at a scan rate of 50 mV / s within a potential window of 0.5 - 2.3 V.

6. The preparation method of an electrocatalytic electrode plate according to claim 3, characterized in that: In Step 3, the potentiostatic method is: applying a constant potential of 2.0 - 2.5 V to the working electrode (1) for 1 - 60 seconds.

7. The preparation method of an electrocatalytic electrode plate according to claim 6, characterized in that: In Step 3, the potentiostatic method is: applying a constant potential of 2.3 V to the working electrode (1) for 10 seconds.

8. The preparation method of an electrocatalytic electrode plate according to claim 3, wherein: In Step 3, the reaction solution is an acetonitrile solution containing 5 mM of benzo[1,2-b:4,5-b']dithiophene-4,8-dione and 0.1 M of tetrabutylammonium perchlorate.

9. Application of an electrocatalytic electrode plate as described in Claim 1 as a cathode in the electrocatalytic degradation of azithromycin.

10. Application of an electrocatalytic electrode plate as a cathode in electrocatalytic degradation of azithromycin according to claim 9, characterized in that: Using iridium oxide, ruthenium oxide, platinum sheet or graphite sheet as the anode, a silver / silver chloride electrode as the reference electrode (3), and the electrode solution of the reference electrode (3) being 3 M or saturated potassium chloride, and performing electrocatalytic degradation at a constant potential of -0.7 - 1.0 V in an oxygenated aqueous solution.

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