Device and method for preparing ozone gas through electrocatalysis without ion exchange membrane

Abstract

The invention relates to the technical field of preparation of ozone through electro-catalysis, and discloses a device and a method for preparing ozone gas through electro-catalysis without an ion exchange membrane. The device comprises a porous anode, a porous cathode, a hydrophilic insulating diaphragm, an anode collector plate with a gas flow channel, a cathode collector plate with a gas flow channel and an electrolyte chamber, and the porous anode and the porous cathode are separated by the hydrophilic insulating diaphragm. The hydrophilic insulating diaphragm guides and restrains electrolyte on the surfaces of the porous anode and the cathode through capillary action, in the electrifying process, electrocatalytic oxidation of water occurs on the surface of the porous anode, ozone is generated, external air is fed into a flow channel of the anode collector plate, and then ozone gas generated by the anode is brought out of the anode. The device can efficiently generate ozone gas under the conditions of room temperature and neutral electrolyte solution, and has the advantages of excellent Faraday efficiency, good safety, wide application field and wide application prospect.

Description

Technical Field

[0001] The invention belongs to the technical field of ozone preparation in electrocatalysis, and specifically relates to a device for preparing ozone gas by electrocatalysis without an ion exchange membrane and a method for electrochemically producing ozone gas. Background Art

[0002] Ozone is a highly oxidizing gas, often used as an oxidant and disinfectant, and is widely used in sterilization, sewage treatment, and air purification. Common methods for purifying indoor air include physical, biological, and chemical methods; however, physical and biological methods are time-consuming, adsorption is not thorough, and purification capacity is limited. The chemical method uses photocatalyst technology and negative ion technology, which requires light and appropriate temperature. It is expensive and has limited coverage, and has limited treatment of harmful gases and floating bacteria. Based on this condition, we set our sights on ozone, which has extremely strong oxidizing properties and is a green and environmentally friendly product, in the hope of using this characteristic of ozone to purify indoor pollutants.

[0003] The main ways to prepare ozone in industry are ultraviolet radiation, dielectric barrier discharge and electrolysis. Compared with the other two methods, the electrolysis method is easy to operate, has mild reaction conditions, does not require the addition of chemical reagents during the treatment process, and does not cause secondary pollution, so it is widely used. At present, most of the devices for preparing ozone by electrochemical methods use pure oxygen as the oxygen source, which is expensive. In addition, the electrolysis method needs to be carried out in an acidic electrolyte to reduce the rate of ozone decomposition. Long-term acidic environment may cause corrosion of the catalyst and severe hydrogen evolution reaction, as well as the inevitable competitive relationship between oxygen and ozone produced at the anode, which makes it impossible to effectively improve the Faraday efficiency of ozone production. More importantly, the ozone prepared by the current electrolysis method exists in the form of ozone water in the liquid phase, and it is impossible to efficiently produce dry ozone gas in one step. Separating ozone water requires gas-liquid separators, cooling systems, drying equipment, etc., which are expensive and complex. At the same time, part of the ozone may be decomposed or lost during the separation process, resulting in a reduction in the actual amount of available ozone.

[0004] The core of electrochemical catalytic oxidation technology is the anode material. The traditional PbO 2 The electrode surface coating will peel off and enter the water, releasing Pb into the water. 4+ , causing pollution to the electrolyte and products. Boron-doped diamond electrodes are electrochemically stable and have a high oxygen evolution potential, but their high cost makes them inapplicable to industrial production. Therefore, the preparation of efficient, stable and low-cost anodes is the current research focus. In recent years, tin-antimony electrodes, as non-precious metals, have attracted people's attention due to their low cost, excellent conductivity, corrosion resistance and high oxygen evolution overpotential. After modification, tin-antimony electrodes can oxidize water at an appropriate voltage to produce active oxygen species mainly composed of hydroxyl radicals, and have good mechanical impact resistance.

[0005] Therefore, developing a low-cost and efficient ozone-generating anode material and a method and device for efficiently generating ozone gas with low energy consumption has important environmental and economic benefits. Summary of the invention

[0006] The purpose of the present invention is to provide an ion exchange membrane-free electrocatalytic preparation of ozone gas and an electrochemical method for producing ozone gas in view of the deficiencies of the prior art. The nickel-doped tin antimony oxide electrode provided by the present invention significantly improves the activity of the tin antimony oxide electrode by nickel doping, and the ion exchange membrane-free electrochemical ozone gas generation device provided can efficiently generate ozone gas at room temperature and neutral electrolyte solution conditions, and has excellent Faraday efficiency. In addition, the cathode of the device undergoes a reaction of reducing oxygen to water, which can avoid the safety hazard caused by the hydrogen evolution reaction at the cathode under factory conditions.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides an ion exchange membrane-free electrocatalytic ozone gas preparation device, comprising: a porous anode, a porous cathode, a hydrophilic insulating membrane, an anode current collector plate with a gas flow channel and a cathode current collector plate, and an electrolyte chamber, wherein the anode current collector plate with a gas flow channel, the porous anode, the hydrophilic insulating membrane, the porous cathode and the cathode current collector plate with a gas flow channel are arranged in sequence, the hydrophilic insulating membrane is arranged between the porous anode and the porous cathode to separate the porous anode and the porous cathode, and the electrolyte chamber is provided with a gas flow channel. The anode current collecting plate and the cathode current collecting plate clamp and seal the porous anode, the hydrophilic insulating membrane and the porous cathode to form an electrochemical device. The anode side of the electrochemical device forms an anode chamber, and the cathode side forms a cathode chamber. The hydrophilic insulating membrane extends into the electrolyte chamber below and absorbs the electrolyte solution by capillary action. The porous anode is a nickel-doped antimony tin oxide electrode, including nickel-doped antimony tin oxide grown on a titanium fiber felt substrate. The nickel in the nickel-doped antimony tin oxide is uniformly distributed in the antimony tin oxide layer at a content of 0.1-0.6at%.

[0008] According to the above scheme, the porous cathode is a porous titanium substrate loaded with platinum or platinum alloy material, located between the cathode collector with gas flow channels and the insulating diaphragm on the cathode chamber side, and is used to reduce oxygen to water. Continuing with the above solution, the anode current collecting plate is provided with a gas guide channel in a folded arrangement, and the cathode current collecting plate is provided with a gas guide channel in a folded arrangement.

[0009] Continuing with the above solution, the anode current collecting plate is provided with a first opening and a second opening on the outside for inputting and outputting gas, and the cathode current collecting plate is provided with a third opening and a fourth opening on the outside for inputting and outputting gas.

[0010] Continuing with the above scheme, the device for electrocatalytically preparing ozone gas also includes a gas supply unit, the second opening of the anode current collecting plate is connected to the gas supply unit pipeline to allow room temperature air to enter, the oxygen in the room temperature air reaches the anode catalyst layer through the gas flow channel of the anode current collecting plate, and the oxygen is oxidized to generate ozone in the reaction, and the first opening of the anode collecting plate is connected to the air intake pipeline of the optical ozone detector for detecting the ozone concentration.

[0011] Continuing with the above scheme, the fourth opening of the cathode current collecting plate is connected to the air supply unit pipeline to allow room temperature air to enter. The oxygen in the room temperature air reaches the cathode catalyst layer through the gas flow channel of the cathode current collecting plate to undergo oxygen reduction reaction to generate water. The third opening of the cathode current collecting plate is connected to the atmosphere.

[0012] Continuing with the above scheme, a first titanium sheet is placed on the upper part of the anode current collecting plate, and a second titanium sheet is placed on the upper part of the cathode current collecting plate, so that they are in contact with the anode current collecting plate / cathode current collecting plate and partially exposed outside the reactor. The anode is connected to the positive pole of the power supply, and the cathode is connected to the negative pole of the power supply, thereby ensuring conductivity.

[0013] Continuing with the above scheme, the insulating membrane is tightly fitted between the porous anode and the porous cathode, and the hydrophilic insulating membrane extends into the electrolyte chamber below the current collecting plate, continuously absorbing the electrolyte solution upward by capillary action, and constraining the electrolyte to form a thin liquid layer on the porous anode and the porous cathode.

[0014] Continuing with the above scheme, the electrochemical device for electrochemically generating ozone also includes a first sealing gasket and a second sealing gasket respectively arranged between the anode current collecting plate and the insulating diaphragm, and between the cathode current collecting plate and the insulating diaphragm, for embedding the porous anode and the porous cathode and ensuring sealing.

[0015] Continuing with the above scheme, the electrolyte solution is a neutral sulfate or phosphate solution, and the hydrophilic insulating membrane is a hydrophilic polyethersulfone or nylon filter membrane obtained by hydrophilic treatment such as oxygen plasma treatment, with a pore size of 0.1-0.5 microns and a thickness of 0.1-0.4 mm.

[0016] A method for electrochemically generating ozone gas based on the above-mentioned device for electrocatalytic preparation of ozone gas without ion exchange membrane comprises the following steps: introducing room temperature air into the anode current collecting plate of the anode chamber and the cathode current collecting plate of the cathode chamber respectively, and applying 15-300 mA / cm between the porous anode and the porous cathode. 2 Constant current, power on to electrochemically prepare ozone gas.

[0017] Following the above scheme, the air supply unit provides dry room temperature air and controls the flow rate to be 50~10000mL / min.

[0018] Continuing with the above scheme, the method for preparing the nickel-doped antimony tin oxide electrode comprises the following steps: 1) Pretreatment of titanium substrate: grinding, surface degreasing and acid etching of titanium fiber felt substrate; 2) Heat treatment: a precursor solution prepared by tin-containing compounds, antimony-containing compounds and nickel-containing compounds is deposited on the surface of titanium fiber felt by ultrasonic spray pyrolysis using an ultrasonic spray pyrolysis apparatus to form a uniform and dense nickel-doped tin antimony oxide film layer. After spraying, calcination is performed to obtain a nickel-doped tin antimony oxide electrode.

[0019] According to the above scheme, the porosity of the titanium fiber felt matrix in step 1) is 50% to 70%, and the thickness is 400 to 800 microns.

[0020] According to the above scheme, in step 1), the surface of the titanium fiber felt is first polished using sandpaper of different mesh sizes, and then rinsed with deionized water; secondly, the surface of the titanium felt is degreased using alkaline solution, and then rinsed with deionized water; finally, oxalic acid is used for heating and etching to remove the oxide film on the surface of the titanium felt, and the surface is rinsed with deionized water and dried.

[0021] In some specific embodiments, the degreasing treatment in step 1) is that the alkali solution is a mixed solution of 5% sodium hydroxide and 5% sodium bicarbonate by mass concentration, the cathode electrochemical degreasing, the current is 0.1 A, the degreasing is performed for 5 minutes, and the degreasing is completed and rinsed with deionized water.

[0022] According to the above scheme, the acid etching is oxalic acid etching to remove the oxide layer on the surface of the substrate. In a specific embodiment, the mass concentration of the oxalic acid solution is 10%, the heating temperature is 80-90°C, and the heating time is 2 h.

[0023] According to the above scheme, the tin-containing compound used in step 2) is hydrated tin tetrachloride or hydrated tin dichloride, the antimony-containing compound is antimony trichloride, and the nickel-containing compound is hydrated nickel chloride or hydrated nickel nitrate.

[0024] According to the above scheme, the ratio of the molar amount of nickel element to the molar amount of tin element is 0.002:1~0.012:1.

[0025] According to the above scheme, the concentration of tin in the precursor solution in step 2) is 0.3~1.0 mol / L. The concentration of nickel-doped tin antimony oxide (Ni / Sb-SnO) can be adjusted by configuring different concentrations of tin and antimony in the mixed solution. 2 ) of the tin-antimony ratio, Sb-SnO 2The molar ratio of antimony to tin can be adjusted within the range of 1:5-1:20. The present invention mainly prepares nickel-doped antimony tin oxide by nickel doping. Compared with the antimony tin oxide before doping modification, the ability of the antimony tin oxide to generate hydroxyl radicals is significantly improved, thereby significantly improving the electrocatalytic oxidation activity, and further significantly improving the activity of electrochemically generating ozone and the concentration of electrochemically generated ozone gas. Sb-SnO 2 The tin-antimony ratio is not limited.

[0026] According to the above scheme, the preparation method of the precursor solution is: add the tin-containing compound and the antimony-containing compound to anhydrous ethanol respectively, stir them thoroughly to form solution A and solution B, add solution B dropwise to solution A to form solution C, add the nickel-containing compound to solution C and mix them thoroughly to form precursor solution D.

[0027] According to the above scheme, the step 3) is to place the pretreated titanium fiber felt on a heating table, the temperature of the heating table is controlled at 400-450°C, and then ultrasonic spray pyrolysis treatment is performed, and the precursor solution prepared by tin-containing compounds, antimony-containing compounds and nickel-containing compounds is sprayed on both sides of the pretreated titanium fiber felt. The spraying speed of the precursor solution prepared by tin-containing compounds, antimony-containing compounds and nickel-containing compounds is 0.1-2mL / min, and the front and back sides are sprayed 30-60 times each, and the total spraying amount is 0.7-1mL / cm 2 After spraying, the electrode sheet is calcined at high temperature in a tubular furnace. According to the above scheme, the high temperature calcination temperature is 400~450℃ and the time is 100~130min.

[0028] The invention mainly prepares nickel-doped antimony tin oxide by nickel doping, comprising nickel-doped antimony tin oxide grown on a titanium fiber felt substrate, wherein the nickel in the nickel-doped antimony tin oxide is uniformly distributed in the antimony tin oxide layer at a content of 0.1-0.6 at%, and compared with the antimony tin oxide before doping modification, the ability of the antimony tin oxide to generate hydroxyl radicals can be significantly improved by a small amount of nickel doping, thereby significantly improving its electrocatalytic oxidation activity, enhancing the catalytic performance of the antimony tin oxide electrode, and further improving its ozone generation efficiency, Sb-SnO 2 The antimony-tin ratio is not limited.

[0029] The present invention adopts titanium fiber felt as a matrix, prepares tin salt, antimony salt, nickel salt and organic solvent into a precursor solution by physical mixing, and then prepares a nickel-doped tin antimony oxide electrode by ultrasonic spray pyrolysis and high-temperature calcination. The preparation method is simple and will not destroy the mechanical strength and pore structure of the titanium fiber felt matrix.

[0030] The present invention provides an ion exchange membrane-free electrocatalytic ozone gas preparation device. During the power-on process, water is electrocatalytically oxidized on the porous anode surface and ozone is generated. External air is sent into the flow channel of the anode collector plate, and the ozone gas generated by the anode is then taken out of the anode. The present invention guides and constrains the electrolyte on the surface of the porous anode through capillary action. The high conductivity of the electrolyte layer effectively reduces the electrolysis resistance, reduces the cell pressure, and reduces the reaction energy consumption. At the same time, it can also block the ozone generated by the anode from diffusing to the cathode, ensuring the effective separation of the components in the reactor and the smooth progress of the reaction. At the same time, nickel-doped antimony tin oxide electrodes are used, which ultimately achieves the efficient oxidation of oxygen into ozone gas.

[0031] The beneficial technical effects of the present invention are as follows: 1. After nickel doping, the electrocatalytic oxidation activity of the titanium-based nickel-doped antimony tin oxide electrode of the present invention is significantly improved, and it has excellent ozone production capacity, and can operate at room temperature without additional refrigeration. Compared with the antimony tin oxide before doping, the ozone production of the nickel-doped antimony tin oxide electrode of the present invention is increased by more than 20 times, and it has the advantages of high electrocatalytic activity, long life and good stability. The nickel-doped antimony tin oxide electrode is expected to be used in the field of environmental pollution control.

[0032] 2. The device for preparing ozone gas by electrocatalysis without ion exchange membrane and the process for producing ozone by electrochemical method provided by the present invention adopt gas-solid two-phase reaction conditions to directly generate ozone gas, thus avoiding the conversion of ozone gas into ozone water in liquid environment, significantly increasing the amount of ozone gas produced and the concentration of produced ozone gas, while meeting the ozone demand in gas and liquid phases, with a wider application field and great application prospects; the electrochemical production of ozone has high stability. At the same time, the reaction of oxygen reduction to water occurs at the cathode, replacing the defect of hydrogen evolution reaction at the cathode, greatly improving the safety of the reaction device. The reaction formula is as follows: Anode produces ozone reaction: 3H 2 O→O 3 +6H + +6e - Anode oxygen evolution reaction: 2H 2 O→O 2 +4H + +4e - Cathode reaction: O 2 +4H + +4e - →2H 2 O.

[0033] 3. The device for preparing ozone gas by electrocatalysis without ion exchange membrane and the process for producing ozone by electrochemical method provided by the present invention do not use the high-cost ion exchange membrane, but use the cheap diaphragm to construct the ultra-thin electrolyte layer, and introduce the room temperature air into the anode chamber and the cathode chamber, and use the capillary action of the hydrophilic insulating diaphragm to guide and constrain the electrolyte to react on the surface of the porous anode. The high conductivity of the electrolyte layer can effectively reduce the electrolytic resistance, reduce the cell pressure (ozone can be produced in the range of 3V to 5V of the lower cell pressure), reduce the reaction energy consumption, and at the same time, it can also block the ozone generated by the anode from diffusing to the cathode, ensuring the effective separation of the components in the reactor and the smooth reaction; it has excellent Faraday efficiency. Moreover, the device uses a neutral electrolyte to avoid electrode corrosion and improve the electrode life and stability. The device and process of the present invention have a good application prospect in electrochemically generating ozone for purifying indoor polluted air, and have the advantages of being environmentally friendly and free of secondary pollution. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Scanning electron microscope images of the nickel-doped antimony tin oxide electrode of the present invention at different magnifications.

[0035] Figure 2 This is the element distribution diagram on the surface of the nickel-doped antimony tin oxide electrode in the present invention.

[0036] Figure 3 The nickel-doped antimony tin oxide (Ni / Sb-SnO 2 ) and antimony tin oxide (Sb-SnO 2 ) X-ray photoelectron spectrum of Ni 2p on the surface of the electrode.

[0037] Figure 4 The antimony tin oxide (Sb-SnO 2 ) and nickel-doped antimony tin oxide (Ni / Sb-SnO 2 )Comparison of the effects of electrode electrocatalysis in generating ozone.

[0038] Figure 5 This is a diagram showing the stability performance of the nickel-doped antimony tin oxide electrode in the present invention.

[0039] Figure 6 The schematic diagram of the electrochemical treatment device structure in a specific embodiment of the present invention. In the figure: 1-porous anode; 2-porous cathode; 3-insulating diaphragm; 4-anode current collector with gas flow channel; 5-cathode current collector with gas flow channel; 6-electrolyte chamber; 7-first sealing gasket; 8-second sealing gasket; 9-anode current collector gas flow channel; 10-cathode current collector gas flow channel; 11-first opening; 12-second opening; 13-third opening; 14-fourth opening; 15-anode side conductive titanium sheet; 16-cathode side conductive titanium sheet. Figure 7 It is a cross-sectional structural diagram of an electrochemical treatment device in a specific embodiment of the present invention.

[0040] Figure 8 Schematic diagram of the use of electrochemical preparation of ozone gas in the present invention. DETAILED DESCRIPTION

[0041] The following is to more clearly illustrate the technical solution of the present invention. The specific implementation methods adopted are only used to explain the present invention, but are not limited to the present invention.

[0042] Example 1: Preparation of nickel-doped antimony tin oxide electrode 1) Pretreatment of titanium fiber felt: The size of the titanium fiber felt used is 20mm*20mm*0.6mm. First, use sandpaper of different mesh sizes to mechanically polish the surface of the titanium fiber felt and remove the surrounding burrs, and then rinse it with deionized water; then put the titanium fiber felt in a mixed solution of 5% sodium hydroxide and 5% sodium bicarbonate, and perform cathode degreasing for 5 minutes at a constant current of 100mA, and rinse it with deionized water; finally, soak the titanium fiber felt in a 10% oxalic acid solution, heat it at 85℃ for 2h to remove the oxide film on the surface of the titanium fiber felt, take it out, rinse the surface with deionized water and dry it.

[0043] 2) Preparation of precursor solution: 3.15g SnCl 4 ·5H 2 O was added into 24 mL of anhydrous ethanol and stirred for 30 min, which was recorded as solution A. 0.204 g SbCl 3 Add 6 mL of anhydrous ethanol and stir thoroughly for 30 min, which is recorded as solution B. Slowly add solution B drop by drop into solution A and stir for 30 min to make it fully mixed to form solution C. Add 513 µL of NiCl with a concentration of 0.025 g / mL to solution C. 2 6H 2 O is mixed thoroughly to form a precursor solution D.

[0044] 3) Heat treatment: The pretreated titanium fiber felt was placed on the heating table of the ultrasonic spray pyrolyzer at a temperature of 420°C. At the same time, the precursor solution D was drawn into a syringe and loaded into the pyrolyzer pipeline. After setting the spray pyrolysis parameters, the electrode preparation was started. The ultrasonic spray pyrolyzer formed a uniform and dense nickel-containing tin antimony oxide film on both sides of the titanium felt by atomizing the precursor solution first and then spraying it. Both the front and back sides were sprayed 45 times. After the spraying was completed, the temperature was raised to 400°C at a rate of 10°C / min in a tubular furnace and calcined for 2h to form a nickel-doped tin antimony oxide electrode.

[0045] From the scanning electron microscopy ( Figure 1) It can be seen that the catalytic layer is evenly loaded on the electrode surface. From the element distribution diagram of the electrode after doping ( Figure 2 )It can be seen that the distribution of Sn, Sb, and Ni on the electrode surface is very uniform, indicating that the Ni element has been successfully doped into the electrode surface. Subsequently, the X-ray photoelectron energy spectrum of the nickel-doped antimony tin oxide electrode was tested and the peak fitting was performed. Figure 3 , indicating that Ni is doped into the electrode surface. Table 1 shows the element content ratio of the surface of the nickel-doped antimony tin oxide electrode in the present invention.

[0046] The results in Table 1 show that the nickel content is 0.31 at%.

[0047] Table 1

[0048] Example 2: Construction and operation of a nickel-doped antimony tin oxide electrode for electrochemical ozone generation The electrochemical device for electrochemically generating ozone used in the embodiments of the present invention is as follows: Figure 6 and Figure 7 As shown, the electrochemical ozone generating device comprises a porous anode 1, a porous cathode 2, a hydrophilic insulating membrane 3, an anode current collecting plate 4 with a gas flow channel located on the anode side and a cathode current collecting plate 5 with a gas flow channel located on the cathode side, and an electrolyte chamber 6. A first sealing gasket 7 and a second sealing gasket 8 are respectively provided between the anode current collecting plate and the cathode current collecting plate and the insulating membrane 3, which are used to embed the porous anode and the porous cathode and ensure the sealing of the gas at the same time; the anode current collecting plate with a gas flow channel, the porous anode, the first sealing gasket, the insulating membrane, the porous cathode, the second sealing gasket, and the cathode current collecting plate with a gas flow channel are clamped by fixing bolts to form an electrochemical ozone generating device, the anode side of the electrochemical device forms an anode chamber, the cathode side forms a cathode chamber, and the gas flow to the anode side is released through the second opening 12. Room temperature air is introduced into the gas flow channel on the cathode side through the fourth opening 14, and the third opening 13 is connected to the atmosphere. The air in the anode chamber can pass through the gas flow channel on the anode current collecting plate 4 to contact the anode, and the air in the cathode chamber can pass through the gas flow channel on the cathode current collecting plate 5 to contact the cathode. The hydrophilic insulating diaphragm 3 extends into the electrolyte chamber 6 below the current collecting plate, absorbs the electrolyte solution through capillary action, and constrains the electrolyte to form a thin liquid layer on the porous anode and the porous cathode. A titanium sheet 15 is placed on the upper part of the cover plate of the anode current collecting plate 4, and a titanium sheet 16 is placed on the upper part of the cover plate of the cathode current collecting plate 5, so that it is in contact with the electrode sheet and partially exposed outside the reactor. The anode is connected to the positive electrode of the power supply, and the cathode is connected to the negative electrode of the power supply, thereby ensuring conductivity.

[0049] Electrochemical ozone generation method: The prepared nickel-doped tin antimony oxide electrode is used as a porous anode, the platinum-plated titanium substrate is used as a porous cathode, and 50 mmol / L Na2 SO 4 As an electrolyte solution, a hydrophilic insulating membrane is placed between an anode and a cathode. Two current collectors with gas flow channels clamp and seal the porous anode, the hydrophilic insulating membrane and the porous cathode to form an electrochemical ozone generation device. The anode side of the electrochemical device forms an anode chamber, and the cathode side forms a cathode chamber. The hydrophilic insulating membrane extends into the electrolyte chamber below the current collector, absorbs the electrolyte solution by capillary action, and constrains the electrolyte to form a thin liquid layer on the porous anode and the porous cathode. Room temperature air is introduced into the gas flow channels of the anode current collector and the cathode current collector at a flow rate of 100 mL / min, and 25 mA / cm 2 Constant current, power on to generate ozone electrochemically. At the same time, tin oxide antimony electrode was used as the anode of the control group experiment, and ozone was generated electrochemically under the same conditions. The experimental results are as follows Figure 4 As shown, the concentration of ozone generated by the nickel-doped tin antimony oxide electrode of the present invention (about 217 ppm) is much higher than that of the tin antimony oxide electrode (about 15 ppm).

[0050] Example 3: Stability of electrochemical ozone generation by nickel-doped antimony tin oxide The nickel-doped antimony tin oxide electrode prepared in Example 1 was used as the porous anode, the platinum-plated titanium fiber felt was used as the porous cathode, and 50 mmol / L Na 2 SO 4 As the electrolyte solution, the constant current was set to 100 mA, the reaction was carried out for 25 hours, and the concentration of the produced ozone was detected using an optical ozone detector. Figure 5 As shown, after 25 hours of power-on, the ozone concentration produced by the nickel-doped tin antimony oxide electrode can still be maintained at around 200 ppm, indicating that the electrode has good stability.

[0051] Example 4: Electrochemical Ozone Generation Activity of Nickel-doped Antimony Tin Oxide Electrodes at Different Concentrations The titanium fiber felt was pretreated according to step 1) in Example 1; when the precursor solution was prepared according to step 2) in Example 1, 171 μL and 855 μL of NiCl with a concentration of 0.025 g / mL were added to the obtained solution C respectively. 2 6H 2 O solution, and fully mixed to form two precursor solutions D with different nickel doping ratios; heat-treating the titanium fiber felt according to step 3) in Example 1 to obtain two electrodes in which nickel is doped in antimony tin oxide at 0.1at% and 0.5at% doping amounts, respectively. Figure 6 The electrochemical device shown in the figure was used to build an electrochemical ozone generation device, and room temperature air was introduced into the gas flow channels of the anode current collector and the cathode current collector at a flow rate of 100 mL / min, and 25 mA / cm was applied between the anode and the cathode. 2The constant current is applied to generate ozone electrochemically. The experimental results show that the ozone concentration in the outgas of the electrode obtained by doping nickel in antimony tin oxide at a doping amount of 0.1at% and 0.5at% can reach 186ppm and 198ppm respectively within 4 hours, both of which have high electrochemical ozone generation activity.

[0052] Example 5: Preliminary practice of industrial-scale application of the present invention A titanium fiber felt with a size of 20 cm*20 cm*0.6 mm was selected as the substrate, and nickel-doped antimony tin oxide of this size was prepared by the method in Example 1 and used as a porous anode. A platinum-plated titanium fiber felt with a similar size was selected as a porous cathode. 50 mmol / L Na 2 SO 4 As electrolyte solution, Figure 6 and Figure 7 The electrochemical device shown in the figure is used to build an electrochemical ozone generation device, such as Figure 8 As shown, room temperature air was introduced into the gas flow channels of the anode current collector and the cathode current collector at a flow rate of 10 L / min, and a 25 mA / cm 2 Constant current, power on for electrochemical ozone generation, the generated ozone concentration reaches 300ppm. The generated high concentration ozone can be diluted and used for disinfection in hospitals, subways, supermarkets and other spaces, with a wider range of applications.

[0053] In contrast, other research reports mostly use traditional ion membrane exchange devices to electrolyze ozone, and electrolysis is carried out in an aqueous electrolyte. Ozone is mostly present in the aqueous phase in a dissolved state, and the concentration of ozone gas entering the gas phase is usually 5-8 ppm. Therefore, the device of the present invention is conducive to obtaining high-concentration ozone gas, which has significant advantages.

[0054] It should be understood that those skilled in the art can make improvements or changes based on the above description, and all these improvements and changes should fall within the scope of protection of the appended claims of the present invention.

Claims

1. A device for electrocatalytically preparing ozone gas without an ion exchange membrane, characterized in that: include: A porous anode, a porous cathode, a hydrophilic insulating diaphragm, an anode current collecting plate and a cathode current collecting plate with gas flow channels, and an electrolyte chamber. The anode current collecting plate with gas flow channels, the porous anode, the hydrophilic insulating diaphragm, the porous cathode and the cathode current collecting plate with gas flow channels are arranged in sequence. The hydrophilic insulating diaphragm is arranged between the porous anode and the porous cathode to separate the porous anode and the porous cathode. The anode current collecting plate and the cathode current collecting plate with gas flow channels clamp and seal the porous anode, the hydrophilic insulating diaphragm and the porous cathode to form an electrochemical device. The anode side of the electrochemical device forms an anode chamber, and the cathode side forms a cathode chamber. The hydrophilic insulating diaphragm extends into the electrolyte chamber below to absorb the electrolyte solution by capillary action. The porous anode is a nickel-doped antimony tin oxide electrode, including nickel-doped antimony tin oxide grown on a titanium fiber felt substrate, and the nickel in the nickel-doped antimony tin oxide is uniformly distributed in the antimony tin oxide layer at a content of 0.1-0.6at%.

2. The device for electrocatalytic production of ozone gas without ion exchange membrane according to claim 1, characterized in that: The insulating membrane is tightly fitted between the porous anode and the porous cathode, and the hydrophilic insulating membrane extends into the electrolyte chamber below the current collecting plate, continuously absorbing the electrolyte solution upward by capillary action, and constraining the electrolyte to form a thin liquid layer on the porous anode and the porous cathode.

3. The device for electrocatalytic production of ozone gas without ion exchange membrane according to claim 1, characterized in that: The porous cathode is a porous titanium substrate loaded with platinum or platinum alloy material, located between the cathode current collector with gas flow channels and the insulating diaphragm on the cathode chamber side, and is used to reduce oxygen to water; The anode current collecting plate is provided with a gas guide channel in a folded arrangement, and the cathode current collecting plate is provided with a gas guide channel in a folded arrangement; The anode current collector plate is provided with a first opening and a second opening on the outside for inputting and outputting gas, and the cathode current collector plate is provided with a third opening and a fourth opening on the outside for inputting and outputting gas; A first titanium sheet is placed on the anode current collector plate, and a second titanium sheet is placed on the cathode current collector plate, so that they are in contact with the anode current collector plate / cathode current collector plate and partially exposed outside the reactor. The anode is connected to the positive pole of the power supply, and the cathode is connected to the negative pole of the power supply.

4. The device for electrocatalytic production of ozone gas without ion exchange membrane according to claim 1, characterized in that: It also includes an air supply unit, the second opening of the anode current collecting plate is connected to the pipeline of the air supply unit to allow room temperature air to enter, the oxygen in the room temperature air reaches the anode catalyst layer through the gas flow channel of the anode current collecting plate, and a reaction of oxygen oxidation to generate ozone occurs; the first opening of the anode collecting plate is connected to the air intake pipeline of the optical ozone detector to detect the ozone concentration; the fourth opening of the cathode current collecting plate is connected to the pipeline of the air supply unit to allow room temperature air to enter, the oxygen in the room temperature air reaches the cathode catalyst layer through the gas flow channel of the cathode current collecting plate, and a reaction of oxygen reduction to generate water occurs, and the third opening of the cathode current collecting plate is connected to the atmosphere.

5. The device for electrocatalytic production of ozone gas without ion exchange membrane according to claim 1, characterized in that: The electrochemical device for electrochemically generating ozone also includes a first sealing gasket and a second sealing gasket respectively arranged between the anode current collecting plate and the insulating diaphragm, and between the cathode current collecting plate and the insulating diaphragm, for embedding the porous anode and the porous cathode and ensuring sealing.

6. The device for electrocatalytic production of ozone gas without ion exchange membrane according to claim 1, characterized in that: The electrolyte solution is a neutral sulfate or phosphate solution, and the hydrophilic insulating membrane is a hydrophilic polyethersulfone or nylon filter membrane obtained through hydrophilic treatment, with a pore size of 0.1-0.5 microns and a thickness of 0.1-0.4 millimeters.

7. The device for electrocatalytic production of ozone gas without ion exchange membrane according to claim 1, characterized in that: The method for preparing the nickel-doped antimony tin oxide electrode comprises the following steps: 1) Pretreatment of titanium substrate: grinding, surface degreasing and acid etching of titanium fiber felt substrate; 2) Heat treatment: a precursor solution prepared by tin-containing compounds, antimony-containing compounds and nickel-containing compounds is deposited on the surface of titanium fiber felt by ultrasonic spray pyrolysis using an ultrasonic spray pyrolysis apparatus to form a uniform and dense nickel-doped tin antimony oxide film layer. After spraying, calcination is performed to obtain a nickel-doped tin antimony oxide electrode.

8. The device for producing ozone gas by electrocatalysis without an ion exchange membrane according to claim 7, characterized in that: The porosity of the titanium fiber felt substrate in step 1) is 50% to 70%, and the thickness is 400 to 800 microns; the acid etching is oxalic acid etching to remove the oxide layer on the surface of the substrate; The tin-containing compound used in step 2) is hydrated tin tetrachloride or hydrated tin dichloride, the antimony-containing compound is antimony trichloride, and the nickel-containing compound is hydrated nickel chloride or hydrated nickel nitrate; the concentration of tin in the precursor solution in step 2) is 0.3-1.0 mol / L; and the ratio of the molar amount of the nickel element to the molar amount of the tin element is 0.002:1-0.012:

1.

9. The device for electrocatalytic production of ozone gas without ion exchange membrane according to claim 7, characterized in that: The step 3) is to place the pretreated titanium fiber felt on a heating table, the temperature of the heating table is controlled at 400-450°C, and then ultrasonic spray pyrolysis treatment is performed, and the precursor solution prepared by the tin compound, the antimony compound and the nickel compound is sprayed on both sides of the pretreated titanium fiber felt, the spraying speed of the precursor solution prepared by the tin compound, the antimony compound and the nickel compound is 0.1-2mL / min, the front and back sides are sprayed 30-60 times, and the total spraying amount is 0.7-1mL / cm 2 After spraying, the electrode sheet is calcined at high temperature in a tubular furnace; the high temperature calcination temperature is 400~450℃ and the time is 100~130min.

10. A method for electrochemically generating ozone gas based on the device for electrocatalytic preparation of ozone gas without ion exchange membrane according to claim 1, characterized in that: Air at room temperature is introduced into the anode current collector of the anode chamber and the cathode current collector of the cathode chamber, and 15-300 mA / cm is applied between the porous anode and the porous cathode. 2 Constant current, power on to electrochemically prepare ozone gas.

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