Electrode assembly for generating hydrogen peroxide in situ, electrolysis device and application thereof

Abstract

The invention belongs to the technical field of electrochemistry, and particularly relates to an electrode assembly for in-situ production of hydrogen peroxide, an electrolysis device and application thereof. The electrode assembly comprises a cathode and an anode; the cathode comprises a waterproof gas-permeable membrane, a metal collector layer and a catalytic membrane which are stacked in sequence; the anode comprises a titanium substrate and an active layer on the surface of the titanium substrate, the active layer is made of metal oxide, metal elements in the metal oxide comprise ruthenium, iridium and tin, and the molar ratio of ruthenium to iridium to tin is (55-65): (2-8): (30-40). The electrode assembly takes water and oxygen as raw materials, H2O2 is generated through a two-electron oxygen reduction (2e-ORR) or water oxidation (2e-WOR) reaction, reaction byproducts are only water and oxygen, an organic pollution source generated due to the fact that an organic solvent needs to be used in a traditional anthraquinone method is completely avoided, 'production and use 'of hydrogen peroxide is achieved, and the production cost is reduced. The use requirements of sterilization, deodorization and organic pollutant degradation in different scenes can be met.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of electrochemistry, and particularly relates to an electrode assembly for in-situ generation of hydrogen peroxide, an electrolytic device and application thereof. BACKGROUND

[0002] Hydrogen peroxide (H2O2) is an important green oxidant and is widely used in medical disinfection, sewage treatment, pulp bleaching and fine chemical industry. Traditional industrial preparation of hydrogen peroxide mainly relies on anthraquinone cycle method, but this process has problems such as high energy consumption, multi-step reaction, organic solvent pollution and H2O2 storage and transportation risk. And it needs large centralized equipment, which is difficult to meet the distributed demand.

[0003] Electrochemical method becomes a substitution direction due to its present preparation and present use characteristics, but the traditional electrochemical device is limited by low catalyst efficiency, single reactor design and difficulty in large-scale application. SUMMARY

[0004] The purpose of the present application is to provide an electrode assembly for in-situ generation of hydrogen peroxide, an electrolytic device and application thereof, to realize "just-in-time production and use" of hydrogen peroxide, high efficiency, good stability, simple process, controllable cost, and to meet the use demand of sterilization, deodorization and degradation of organic pollutants in different scenes.

[0005] Specifically, the present application provides the following technical solutions:

[0006] An electrode assembly for in-situ generation of hydrogen peroxide, comprising a cathode and an anode;

[0007] The cathode comprises a waterproof and breathable film, a metal current collecting layer and a catalytic film which are stacked in sequence;

[0008] The anode comprises a titanium substrate and an active layer on the surface of the titanium substrate, the material of the active layer comprises a metal oxide, the metal elements in the metal oxide comprise ruthenium, iridium and tin, and the molar ratio of the ruthenium, iridium and tin is (55-65):(2-8):(30-40).

[0009] As preferred, the preparation method of the cathode comprises the following steps:

[0010] 1) uniformly mixing carbon powder, acetylene black and polytetrafluoroethylene, then pressing the obtained mixture into a sheet with a double roller mill, and further drying to obtain a waterproof and breathable film;

[0011] 2) uniformly mixing an oxygen reduction catalyst, acetylene black and polytetrafluoroethylene, then pressing the obtained mixture into a sheet with a double roller mill, and further drying to obtain a catalytic film;

[0012] 3) sequentially stacking the waterproof and air-permeable membrane, the metal current collector and the catalytic membrane, then pressing and compounding, and finally sintering and forming to obtain the cathode.

[0013] Further preferably, in step 2), the oxygen reduction catalyst is at least one of graphite, oxidized activated carbon, doped activated carbon, carbon-based single-atom catalyst, and activated carbon carrier catalyst.

[0014] Further preferably, in step 3), the metal current collector is a metal punched net with a mesh density of 10-50 meshes and a mesh thickness of 0.1-0.4 mm, and is made of stainless steel, copper, titanium or nickel.

[0015] Further preferably, in step 3), the sintering and forming temperature is 250-320℃. It is found that if the sintering and forming temperature is lower than 250℃, the removal of the surfactant in PTFE is affected, thereby affecting the electro-reduction process of oxygen in the cathode and reducing the electrode performance; if the temperature is higher than 320℃, the molecular structure of the membrane electrode is deteriorated, which reduces the tensile performance of the membrane electrode, thereby reducing the performance and service life of the membrane electrode assembly and reducing the mechanical performance and processing quality.

[0016] As preferred, the preparation method of the anode comprises the following steps:

[0017] A) preparing an ethanol solution of ruthenium trichloride, chloro iridic acid and tin tetrachloride to obtain a mixed metal salt solution;

[0018] B) uniformly coating the mixed metal salt solution on a titanium substrate, then drying the titanium substrate, and then transferring it to a muffle furnace for sintering, repeating the coating-drying-sintering for 10-30 times to obtain a titanium substrate with an active layer on the surface.

[0019] Further preferably, before forming the active layer on the titanium substrate, a step of pretreating the titanium substrate is further included:

[0020] The titanium substrate is sequentially placed in an alkaline solution and an acidic solution for boiling treatment, then washed with water and dried for standby use. Through the above pretreatment, the oxides and grease impurities on the surface of the titanium substrate can be removed, and the surface of the titanium substrate can be etched to facilitate the adhesion of the coating.

[0021] Further preferably, in step B), the mixed metal salt solution is coated at a rate of 4-8 mL per 1 m 2 The coating amount of the titanium substrate is 4-8 mL.

[0022] Further preferably, in step B), the sintering temperature is 350-550℃ and the time is 5-20 minutes.

[0023] Further preferably, in step B), the thickness of the active layer is 2-8 μm.

[0024] The application also provides an electrolytic device for generating hydrogen peroxide in situ, comprising the electrode assembly and an open-top shell.

[0025] A partition plate with a mounting hole is arranged in the shell to divide the accommodating cavity of the shell into an upper accommodating cavity and a lower accommodating cavity.

[0026] A clamping groove is arranged in the upper accommodating cavity, and the cathode and the anode of the electrode assembly are arranged in the clamping groove in parallel and perpendicularly to the partition plate, and a gap for electrolyte flow is arranged between the cathode and the anode.

[0027] A spring is arranged in the lower accommodating cavity, and the cathode and the anode are connected to an electric connection device through the spring and connected to the negative pole and the positive pole of a direct-current power supply through the electric connection device.

[0028] Preferably, the clamping groove is arranged on the partition plate, and a groove is arranged on the surface of the partition plate around the clamping groove, and a sealing ring is embedded in the groove.

[0029] The spring is packaged in the lower accommodating cavity by epoxy glue.

[0030] Preferably, the current density of the direct-current power supply is 10-60 mA / cm 2 , and more preferably 14-18 mA / cm 2 .

[0031] The application also provides the application of the electrolytic device in a water purification device.

[0032] The application has the following beneficial effects:

[0033] (1) The electrode assembly for generating hydrogen peroxide in situ provided by the application generates H2O2 by two-electron oxygen reduction (2e - -ORR) or water oxidation (2e - -WOR) reaction using water and oxygen as raw materials, and the by-product of the reaction is only water and oxygen, completely avoiding the organic pollution source caused by the use of organic solvents in the traditional anthraquinone method.

[0034] (2) The electrode assembly for generating hydrogen peroxide in situ provided by the application can directly electrolyze tap water to generate hydrogen peroxide solution without additional addition of chemical reagents, and has the advantages of high efficiency, good stability, simple process, controllable cost, realization of "production and use at the same time", and wide application in water sterilization and air purification.

[0035] (3) The electrode assembly for in-situ generation of hydrogen peroxide provided by the application is a gas-solid-liquid three-phase composite cathode composed of a catalytic membrane, a metal current collector and a waterproof and air-permeable membrane, which improves the catalyst loading of the catalytic membrane surface of the composite air cathode per unit area, enhances the plasticity and tensile resistance of the membrane air electrode, and makes the membrane electrode have higher structural strength and oxygen reduction performance;

[0036] (4) The electrode assembly for in-situ generation of hydrogen peroxide provided by the application adjusts the thickness and uniformity of the anode coating by optimizing the concentration ratio of the metal salt solution, the temperature and time of heat treatment and the brushing times, and improves the stability and service life of the electrode;

[0037] (5) The electrolytic device for in-situ generation of hydrogen peroxide provided by the application is designed without a diaphragm, the electrolytic unit is designed as a combinable independent module, and the production capacity can be adjusted by series connection or parallel connection, which has the advantages of high efficiency, good stability, simple preparation process, fast batch production, controllable cost. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The overall structure diagram of the electrolytic device for in-situ generation of hydrogen peroxide described in the specific embodiment.

[0039] Figure 2 The exploded structure diagram of the electrolytic device for in-situ generation of hydrogen peroxide described in the specific embodiment.

[0040] Figure 3 The exploded structure diagram of the electrolytic device for in-situ generation of hydrogen peroxide described in the specific embodiment.

[0041] Figure 4 The SEM diagram of the composite coating titanium anode prepared in Example 1.

[0042] Figure 5 The SEM diagram of the carbon powder / polytetrafluoroethylene composite air cathode prepared in Example 1; wherein the left diagram is a flat section for observing the fiberization degree of the material, i.e., the wire drawing condition; and the right diagram is a vertical section for observing the lamination condition of the material.

[0043] Figure 6 The hydrogen peroxide production diagram of the electrolytic device in Example 1 under different current densities.

[0044] Figure 7 The hydrogen peroxide production diagram of the electrolytic device in Examples 1-3 in different electrolytes.

[0045] Figure 8 The stability test of the electrolytic device in Example 1 for electrolysis of tap water.

[0046] List of reference signs in the figures:

[0047] 1. carbon powder / polytetrafluoroethylene composite air cathode; 11. waterproof and air-permeable membrane; 12. metal current collector; 13. catalytic membrane; 2. composite coated titanium anode; 3. sealing ring; 4. shell; 41. clamping groove; 42. flow gap; 5. spring; 6. electrical connection device; 7. epoxy glue. DETAILED DESCRIPTION

[0048] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. The following embodiments are used to illustrate the present application but not to limit the scope of the present application. If the specific technology or condition is not specified in the embodiments, the technology or condition is carried out according to the technology or condition described in the literature in the art or according to the product instruction.

[0049] The present application first provides an electrode assembly for in-situ generation of hydrogen peroxide, comprising a carbon powder / polytetrafluoroethylene composite air cathode and a composite coated titanium anode.

[0050] The carbon powder / polytetrafluoroethylene composite air cathode comprises a waterproof and air-permeable membrane, a metal current collector layer and a catalytic membrane which are stacked in sequence.

[0051] The composite coated titanium anode comprises a titanium substrate and an active layer on the surface of the titanium substrate, the material of the active layer comprises a metal oxide, the metal elements in the metal oxide comprise ruthenium, iridium and tin, and the molar ratio of the ruthenium, iridium and tin is 60:5:35.

[0052] In a preferred embodiment, the preparation method of the carbon powder / polytetrafluoroethylene composite air cathode is as follows:

[0053] The carbon powder (powder), acetylene black (powder) and polytetrafluoroethylene are uniformly mixed, the obtained mixture is compressed into several sheets by a double roller mill, and the sheets are dried to obtain the waterproof and air-permeable membrane.

[0054] The oxygen reduction catalyst (powder), acetylene black (powder) and polytetrafluoroethylene are uniformly mixed, the obtained mixture is compressed into several sheets by a double roller mill, and the sheets are dried to obtain the catalytic membrane; the oxygen reduction catalyst is activated carbon or activated carbon carrier catalyst.

[0055] The waterproof and air-permeable membrane, the metal current collector and the catalytic membrane are stacked in sequence, and after compression treatment, the carbon powder / polytetrafluoroethylene composite air cathode is obtained, and then the carbon powder / polytetrafluoroethylene composite air cathode is formed by calcination;

[0056] Specifically, get an amount of carbon dust (20-50 μm) and acetylene black (50-100nm) and mix, add dehydrated alcohol and PTFE emulsion (PTFE content 60%, aqueous phase) and mix in a PTFE Fibrotic High Mixing Granulator, be pressed into a C / PTFE thin slice through a roller rubber mixer, the C / PTFE thin slice is put into a baking oven and dried and cut to desired size, the waterproof breathable membrane, a metal current collecting net (titanium mesh, mesh density 10 orders, screen thickness 0.4mm) and a catalyst membrane of the same size are stacked successively, a roller rubber mixer is used to be pressed into electrode material, and finally, in a tetrafluoroethylene sintering furnace, baking molding is performed to obtain a carbon dust / polytetrafluoroethylene composite air cathode. Wherein, in the preparation of the carbon dust / polytetrafluoroethylene composite air cathode, the waterproof breathable membrane and the catalyst membrane drying treatment temperature are 60-100 ℃, the temperature of baking molding is 250-320 ℃, and the roller rubber mixer rolling pressure is 5-20Mpa.

[0057] In a preferred embodiment, the preparation method of the composite coating titanium anode is as follows:

[0058] Specifically, first, ruthenium trichloride, chloroiridic acid, and tin tetrachloride are weighed in a certain molar ratio and added to an ethanol solution, and stirred until completely dissolved to obtain a mixed metal salt solution. Secondly, titanium plates of appropriate size are cut to serve as electrodes, and after being etched with oxalic acid to remove the oxide film, they are washed and dried in distilled water to serve as electrode substrates.

[0059] The mixed metal salt solution is evenly coated on the acid-etched titanium substrate, and then the titanium substrate is dried in an oven at 60-90°C, taken out and cooled to room temperature, and then transferred to a muffle furnace and calcined at 350-550°C for 5-20 minutes. The coating-drying-calcination is repeated 10-30 times to obtain a Ti / RuO2-IrO2-SnO2 coated titanium anode.

[0060] The present invention also provides an electrolysis device for in-situ generation of hydrogen peroxide, such as Figures 1-3 As shown, it includes a shell (4) with upper and lower openings; a partition with mounting holes is provided in the shell (4) to separate the housing cavity of the shell into an upper housing cavity and a lower housing cavity;

[0061] The upper accommodating cavity bottom partition is provided with a clamping groove (41), a carbon powder / polytetrafluoroethylene composite air cathode (1) and a composite coating titanium anode (2) arranged inside the clamping groove (41), and a spring (5) fixed to the lower accommodating cavity by means of hot melt adhesive (7); the carbon powder / polytetrafluoroethylene composite air cathode (1) and the composite coating titanium anode (2) are connected with the spring (5) through fixed mounting holes on the shell (4), the spring (5) is connected with a direct current power supply through an electrical connection device (6), and the carbon powder / polytetrafluoroethylene composite air cathode (1) comprises a waterproof and breathable film (11), a metal current collecting grid (12) and a catalytic film (13) arranged in sequence.

[0062] In a preferred embodiment, the shell (4) is provided with a sealing connection device, which is a sealing ring (3) and epoxy glue (7) arranged around the clamping groove; the sealing ring (3) is arranged in a groove arranged on the upper surface of the partition, and the epoxy glue (7) is arranged inside the lower accommodating cavity.

[0063] In a preferred embodiment, the in-situ hydrogen peroxide generating electrolysis device is arranged in electrolyte in a water purification device, the electrolyte can be mineral water, tap water or Na2SO4, the carbon powder / polytetrafluoroethylene composite air cathode (1) and the composite coating titanium anode (2) are directly contacted with the electrolyte in the water purification device, when the direct current power supply is turned on, the composite coating titanium anode (2) in the electrolyte in the upper accommodating cavity can electrolyze water in the electrolyte into ozone, protons and electrons, and at the same time, a decomposition reaction of hydrogen peroxide occurs; the carbon powder / polytetrafluoroethylene composite air cathode (1) can electrolyze oxygen in water into water together with protons and electrons; the specific reactions are as follows:

[0064] Ti / RuO2-IrO2-SnO2 anode electrolysis: 6H2O→2O3+12H + +12e - ;

[0065] Carbon powder / polytetrafluoroethylene composite air cathode: 2O3+12H + +12e - →6H2O.

[0066] Further, the anode can also have the decomposition reaction of hydrogen peroxide: H2O2→HO2·+H + +e - ; HO2·→O2+H + +e - .

[0067] Further, when the direct current power supply is turned on, oxygen in the electrolyte and water can generate hydrogen peroxide solution under the electrolysis of the carbon powder / polytetrafluoroethylene composite air cathode (1), and the specific reaction is as follows: O2+2H+ + 2e - → 2H2O2.

[0068] Further, the carbon powder / polytetrafluoroethylene composite air cathode (1) produces hydrogen peroxide solution with the functions of sterilization, deodorization and degradation of organic matter.

[0069] Based on the above-mentioned electrolytic device, the application further provides an application, which places the hydrogen peroxide electrolytic device in the body of a water purification device, and the hydrogen peroxide electrolytic device is in direct contact with electrolyte, and the hydrogen peroxide electrolytic device generates hydrogen peroxide solution through electrolysis principle, thereby having the functions of sterilization, deodorization and degradation of organic matter.

[0070] Assembly of the hydrogen peroxide electrolytic device:

[0071] The carbon powder / polytetrafluoroethylene composite air cathode and the composite coating titanium anode are respectively arranged in the clamping groove of the upper accommodating cavity and connected with the spring inserted into the lower accommodating cavity through the fixing mounting hole of the bottom partition plate, and the spring is fixed and sealed in the lower accommodating cavity through epoxy glue; and the spring is connected with the positive and negative poles of the direct current power supply through the electric connection device.

[0072] The technical scheme of the application will be described in detail below through specific implementation cases.

[0073] In the following examples, the roll mixing mill used is YXY-DGWR100 from Shenzhen Yongxing Industry Equipment Technology Co., Ltd.

[0074] In the following examples, the PTFE fiberization high-mix granulator used is GRS-TSG-200 from Wuhan Gries New Energy Co., Ltd.

[0075] In the following examples, the active carbon catalyst is prepared by the following method: a proper amount of commercial Vulcan XC-72R carbon powder is placed in a clean porcelain boat, the porcelain boat is placed in the middle of a tubular furnace, high-temperature heat treatment is carried out at 400℃ under air atmosphere at a heating rate of 7℃ / min for 2 hours, and the temperature is automatically reduced to room temperature, and then the active carbon catalyst powder is obtained.

[0076] Example 1

[0077] Hydrogen peroxide solution is generated by electrolyzing tap water through the hydrogen peroxide electrolytic device

[0078] Preparation of carbon powder / PTFE composite air cathode for hydrogen peroxide production: 15 g of carbon powder (particle size 35 μm) and 20 g of acetylene black (50 nm) were mixed uniformly, 80 g of anhydrous ethanol and 60 g of a PTFE emulsion (PTFE content 60%, aqueous phase) were added, and stirring was carried out in a PTFE fiberization high-mix granulator for 30 min. The mixture was pressed into a C / PTFE sheet of 1 mm in thickness on a two-roller rubber mill, and the sheet was dried in an oven at 80°C to obtain a waterproof and air-permeable film;

[0079] 20 g of self-made activated carbon catalyst (particle size 35 μm) and 15 g of acetylene black (50 nm) were mixed uniformly, 80 g of anhydrous ethanol and 50 g of a PTFE emulsion (PTFE content 60%, aqueous phase) were added, and stirring was carried out in a PTFE fiberization high-mix granulator for 30 min. The mixture was pressed into a C / PTFE sheet of 1 mm in thickness on a two-roller rubber mill, and the sheet was dried in an oven at 80°C to obtain a catalyst film;

[0080] The waterproof and air-permeable film, the titanium mesh (mesh density 10 mesh, mesh thickness 0.4 mm) and the catalyst film were cut to the same size and stacked in sequence, and a composite air electrode with a thickness of 1.7 mm was prepared by pressing on a two-roller rubber mill at 15 MPa. Finally, the composite air electrode was sintered in a four-fluorine sintering furnace at 280°C for 1.5 hours to complete the preparation. Figure 5 SEM image of the carbon powder / PTFE composite air cathode prepared in Example 1.

[0081] Preparation of Ti / RuO2-IrO2-SnO2-coated titanium anode: A sandblasted titanium plate (thickness 0.5 mm) was cut to the appropriate size, placed in a 80°C NaOH (10 wt%) solution for 1 hour to remove oil, then ultrasonically cleaned in distilled water for 3 min, and then placed in a 10% oxalic acid solution for heating at 80°C in a water bath for 90 min to remove the surface oxide film and perform etching, facilitating the adhesion of the coating. The treated titanium plate was ultrasonically cleaned in distilled water for 3 min and dried for use as an electrode substrate.

[0082] According to the molar ratio of 60:5:35, 1.36 g of ruthenium trichloride (RuCl3·H2O), 0.11 g of chloroiridic acid (H2IrCl6·XH2O) and 0.79 g of tin tetrachloride (SnCl4·5H2O) were weighed, 0.5 ml of hydrochloric acid was added to serve as a wetting agent, and the mixture was added to 50 ml of an ethanol solution, and stirred until completely dissolved to obtain a mixed metal salt solution.

[0083] The mixed metal salt solution was uniformly coated onto the titanium substrate using a brush (1 m2 per time). 2The coating amount of the titanium substrate is 4-8 mL), and then the titanium substrate is dried in an oven at 80°C for 10 minutes, taken out and cooled to room temperature, and then transferred to a muffle furnace and calcined at 400°C for 20 minutes. The coating-drying-calcination is repeated 25 times, and the last calcination time is 1 hour. The substrate is taken out and cooled to room temperature to obtain a Ti / RuO2-IrO2-SnO2 coated titanium anode with a coating thickness of 5 μm. Figure 4 This is the SEM image of the composite coating titanium anode prepared in Example 1.

[0084] The carbon powder / polytetrafluoroethylene composite air cathode and Ti / RuO2-IrO2-SnO2 coated titanium anode prepared by the above process were respectively Figure 2 The middle electrode is cut to size and installed in the electrolysis device, such as Figure 1 As shown; the performance test of the electrode in situ generation of hydrogen peroxide was then carried out in a glass container. The hydrogen peroxide electrolysis device was placed in a constant temperature water bath stirrer at a constant temperature of 25°C, and a small magnetic particle was placed in the glass reaction container for continuous stirring. A two-electrode working system was adopted. The carbon powder / polytetrafluoroethylene composite air cathode and the Ti / RuO2-IrO2-SnO2 coated titanium anode were connected to the negative and positive electrodes of an external DC power supply through an electrical connection device. The working dimensions of the two electrodes were 10mmx20mm, and the electrolyte was 150ml of tap water (TDS value 130). The hydrogen peroxide was generated in situ under stirring for 90 minutes by electrolysis, and the current density was 8mA / cm 2 , 12mA / cm 2 , 16mA / cm 2 , 20mA / cm 2 The in-situ production of hydrogen peroxide was carried out under the conditions of , and the concentration of hydrogen peroxide in the reactor was tested every 15 minutes. Figure 6 As shown in the final results, it is shown that when the current density is 16mA / cm 2 When , the hydrogen peroxide content in the solution was the highest, with a concentration of 4.8 mg / L.

[0085] The output of hydrogen peroxide measured in Example 1 Figure 6 As shown in the figure, compared with other control groups, the change of current density during the reaction process has a greater impact on the production of hydrogen peroxide. When the current density is 8-16 mA / cm 2 When the current density is 20mA / cm, the production of hydrogen peroxide increases with the increase of current density. This is because the increase of current density increases the rate of electron migration, accelerates the electrochemical reaction rate, and thus increases the rate of hydrogen peroxide generation. 2hydrogen peroxide was no longer increased, which might be due to the fact that high current density favored the decomposition of the generated hydrogen peroxide at the anode, while the high current density favored the direct reduction of oxygen to water at the electrode surface, and the high current density limited the diffusion of oxygen in the solution, resulting in a decrease in the rate of oxygen reduction reaction, further causing the generation rate of hydrogen peroxide to decrease. In the experiment at different current densities, when the current density was 16 mA / cm 2 , the highest concentration of hydrogen peroxide in the solution was 4.8 mg / L.

[0086] Example 2

[0087] The preparation process of the electrode assembly and the electrolysis device were the same as in Example 1, except that the electrolyte was 150 ml of mineral water (TDS 30), and the in-situ hydrogen peroxide production was carried out at a current density of 16 mA / cm 2 . The concentration of hydrogen peroxide in the reactor was tested every 15 minutes. The final results showed that after 60 min, the hydrogen peroxide generation device could effectively produce a hydrogen peroxide solution with a concentration of 1.6 mg / L, and the total amount of hydrogen peroxide produced reached 0.24 mg; after 60 min, the hydrogen peroxide generation device could effectively produce a hydrogen peroxide solution with a concentration of 2.7 mg / L, and the total amount of hydrogen peroxide produced reached 0.4 mg; after 90 min, the hydrogen peroxide generation device could effectively produce a hydrogen peroxide solution with a concentration of 3.2 mg / L, and the total amount of hydrogen peroxide produced reached 0.48 mg, as shown in Table 2. Figure 7

[0088] Example 3

[0089] The preparation process of the electrode assembly and the electrolysis device were the same as in Example 1, except that the electrolyte was 150 ml of Na2SO4 with a concentration of 0.05 mol / L, and the in-situ hydrogen peroxide production was carried out at a current density of 16 mA / cm 2 . The concentration of hydrogen peroxide in the reactor was tested every 15 minutes. The final results showed that after 30 min, the hydrogen peroxide generation module could effectively produce a hydrogen peroxide solution with a concentration of 2.0 mg / L, and the total amount of hydrogen peroxide produced reached 0.3 mg; after 60 min, the hydrogen peroxide generation module could effectively produce a hydrogen peroxide solution with a concentration of 5.9 mg / L, and the total amount of hydrogen peroxide produced reached more than 0.8 mg; after 90 min, the hydrogen peroxide generation module could effectively produce a hydrogen peroxide solution with a concentration of 7.2 mg / L, and the total amount of hydrogen peroxide produced reached more than 1 mg. As shown in Table 3. Figure 7

[0090] Figure 8 Example 1 at 16 mA / cm 2 ​​The stability test of electrolysis of tap water under the condition shows that the electrolysis device does not attenuate for 200 hours of stable operation, and the examples prove the stability of the in-situ electrolysis hydrogen peroxide device, the electrolysis device can produce hydrogen peroxide solution with certain concentration according to the use demand with small electrode area, and has wide application prospect.

[0091] Although the present application has been described in detail with general description, specific embodiments and experiments, some modifications or improvements can be made on the basis of the present application, which is obvious to those skilled in the art. Therefore, these modifications or improvements made on the basis of not deviating from the spirit of the present application, all belong to the scope of the present application.

Claims

1. An electrode assembly for in-situ generation of hydrogen peroxide, characterized in that: including a cathode and an anode; The cathode comprises a waterproof and breathable membrane, a metal current collecting layer and a catalytic membrane stacked in sequence; The anode includes a titanium substrate and an active layer on its surface. The material of the active layer includes metal oxide. The metal elements in the metal oxide include ruthenium, iridium and tin. The molar ratio of ruthenium, iridium and tin is (55-65):(2-8):(30-40).

2. The electrode assembly for in-situ generation of hydrogen peroxide according to claim 1, characterized in that: The method for preparing the cathode comprises the following steps: 1) mixing carbon powder, acetylene black and polytetrafluoroethylene uniformly, and then pressing the obtained mixture into a sheet using a double-roll rubber mixer, and further drying to obtain a waterproof breathable membrane; 2) mixing the oxygen reduction catalyst, acetylene black, and polytetrafluoroethylene uniformly, and then pressing the obtained mixture into a sheet using a double-roll rubber mill, and further drying to obtain a catalytic membrane; 3) The waterproof and breathable membrane, the metal current collecting mesh and the catalytic membrane are stacked in sequence, then pressed and composited, and finally calcined to obtain the cathode.

3. The electrode assembly for in-situ generation of hydrogen peroxide according to claim 2, characterized in that: In step 2), the oxygen reduction catalyst is at least one of graphite, oxidized activated carbon, doped activated carbon, carbon-based single atom catalyst, and activated carbon-supported catalyst; In step 3), the metal current collecting mesh is a metal stamping mesh with a mesh density of 10-50 meshes, a mesh thickness of 0.1-0.4 mm, and is made of stainless steel, copper, titanium or nickel.

4. The electrode assembly for in-situ generation of hydrogen peroxide according to claim 2, characterized in that: In step 3), the calcination temperature is 250-320°C.

5. An electrode assembly for in-situ generation of hydrogen peroxide according to claim 1 or 2, characterized in that: The method for preparing the anode comprises the following steps: A) preparing an ethanol solution of ruthenium trichloride, chloroiridic acid, and tin tetrachloride to obtain a mixed metal salt solution; B) uniformly coating the mixed metal salt solution on a titanium substrate, then drying the titanium substrate, and then transferring it to a muffle furnace for calcination, repeating coating-drying-calcination 10-30 times to obtain a titanium substrate with an active layer on its surface.

6. The electrode assembly for in-situ generation of hydrogen peroxide according to claim 5, characterized in that: Before forming the active layer on the titanium substrate, the titanium substrate is also pre-treated: The titanium substrate is sequentially placed in an alkaline solution and an acidic solution for boiling treatment, then washed with water and dried for later use.

7. The electrode assembly for in-situ generation of hydrogen peroxide according to claim 5, characterized in that: In step B), the mixed metal salt solution is applied at a rate of 1 m 2 The coating volume of titanium substrate is 4-8mL; And / or, in step B), the calcination temperature is 350-550° C. and the calcination time is 5-20 minutes.

8. The electrode assembly for in-situ generation of hydrogen peroxide according to claim 5, characterized in that: In step B), the thickness of the active layer is 2-8 μm.

9. An electrolysis device for in-situ generation of hydrogen peroxide, characterized in that: include: The electrode assembly and the shell with upper and lower openings according to any one of claims 1 to 8; A partition with mounting holes is provided in the shell to separate the housing cavity of the shell into an upper housing cavity and a lower housing cavity; A slot is provided in the upper accommodating cavity; the cathode and anode of the electrode assembly are arranged in parallel with each other in the slot and perpendicular to the separator; a gap is provided between the cathode and anode for the flow of electrolyte; A plug spring is provided in the lower accommodating cavity, and the cathode and anode are connected to the electrical connection device through the plug spring, and are respectively connected to the negative electrode and positive electrode of the DC power supply through the electrical connection device; Preferably, the card slot is provided on the partition, and a circle of grooves is provided on the surface of the partition around the card slot, and a circle of sealing rings is embedded in the grooves; The plug spring is encapsulated in the lower accommodating cavity by epoxy glue; And / or, the current density of the DC power supply is 10-60 mA / cm 2 , more preferably 14-18 mA / cm 2 .

10. Use of the electrolysis device for in-situ generation of hydrogen peroxide according to claim 9 in a water purification device.

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