Low-cost high-oxygen-evolution ozone electrode coating material and application thereof

Abstract

The invention discloses a low-cost high-oxygen-evolution ozone electrode coating material and application thereof. The preparation method comprises the following steps: dissolving SnCl4, SbCl3 and nano TiO2 powder in an organic solvent, and uniformly stirring to obtain a precursor solution; coating and sintering a Ti plate by using the precursor solution; the coating and sintering treatment comprises the following steps: coating the precursor solution on the surface of a Ti plate, sintering, taking out, and cooling to room temperature; and repeatedly coating, sintering for multiple times, annealing, and cooling to room temperature to obtain a target product. The ozone electrode coating material provided by the invention has the advantages of higher oxygen evolution potential, longer service life, simple preparation process and low cost, and is suitable for industrial production. The ozone electrode coating material is used as an anode to electrolyze water to generate ozone in situ, the mass transfer efficiency of the ozone is improved, the generated ozone is used as an ozone source of the ozone, self-sufficiency is realized, and a complicated mass transfer step required by introducing the ozone from an external gas phase in a traditional method is completely avoided.

Description

Technical Field

[0001] The present invention belongs to the field of electrocatalytic materials and relates to a low-cost, high-oxygen-evolution ozone electrode coating material and an application thereof. Background Art

[0002] Ozone (O3), with its strong oxidizing properties, non-selectivity, and lack of secondary pollution residues, has important applications in water treatment (such as degradation and disinfection of refractory organic matter), air purification (such as VOC removal), industrial synthesis, and environmental monitoring. It is considered an ideal alternative to traditional chlorine disinfection and chemical oxidation. However, the large-scale, efficient production and effective utilization of ozone are highly dependent on the development of high-performance electrode materials and advanced electrochemical systems.

[0003] Since its discovery in the late 19th century, ozone generation technology has evolved from ultraviolet photolysis to corona discharge to electrochemical methods. Among these, electrochemical ozone generators (EOGs) have gradually become the mainstream direction of research and application due to their significant advantages, including the lack of need for high temperature and high pressure, compact equipment, strong controllability, and the ability to generate ozone directly in the liquid phase (avoiding gas-phase mass transfer losses). The core of the electrochemical method lies in the performance of the anode material (ozone electrode), which directly determines the ozone yield, current efficiency, energy consumption, and long-term operational stability of the electrode. Early electrode materials such as lead-based oxides generally suffer from key defects such as low catalytic activity, insufficient oxygen evolution potential leading to poor ozone selectivity, severe electrode corrosion, and short service life, which have seriously restricted the large-scale application of electrochemical ozone technology.

[0004] With increasingly stringent environmental regulations, advanced oxidation processes (AOPs) have garnered widespread attention due to their ability to efficiently mineralize refractory organic pollutants (such as drug residues, endocrine disruptors, and microplastics). As one of the core oxidants in AOPs, demand for ozone has surged. However, the efficient application of ozone in water treatment, particularly for industrial wastewater with complex compositions and high concentrations of refractory substances, still faces significant challenges: 1. Catalyst Performance Bottleneck: Traditional ozone catalytic oxidation technology relies on externally added or supported catalysts (such as metal oxides and activated carbon) to activate ozone to produce highly oxidizing hydroxyl radicals (•OH). However, existing catalysts commonly suffer from issues such as easy dissolution or deactivation of active components, resulting in poor cycle stability, poor selectivity for specific target pollutants, and difficulty in efficiently degrading certain stubborn organic compounds.

[0005] 2. Low ozone utilization efficiency and energy waste: Traditional processes typically require an external gas source (such as air or oxygen) to generate ozone through corona discharge or other methods, which is then introduced into the reaction system. This process is subject to significant mass transfer limitations, resulting in low ozone dissolution efficiency at the gas / liquid interface and the escape of large amounts of unreacted ozone, leading to low ozone utilization and energy waste. Furthermore, the synergistic mechanism between the catalyst and ozone is often inefficient, failing to fully utilize ozone's oxidation potential.

[0006] 3. Mass transfer efficiency limitation: The transfer of ozone from the external gas phase to the reaction liquid phase is a key step that restricts the reaction rate. Its inherent low mass transfer efficiency becomes a bottleneck for improving the overall treatment efficiency.

[0007] In the context of energy transformation and sustainable development, the development of next-generation electrochemical ozone technology places higher comprehensive requirements on electrode materials: High Oxygen Evolution Potential (OEP): This is a key physicochemical parameter for achieving highly selective ozone generation rather than the competitive oxygen evolution reaction (OER). High OEP effectively suppresses OER side reactions and efficiently converts electrical current into ozone.

[0008] High catalytic activity and stability: The electrode needs to maintain long-term stable high catalytic activity in harsh electrochemical oxidation environments, extend service life, and reduce replacement costs.

[0009] Low cost and process feasibility: Material costs are controllable, and the preparation process must meet the requirements of industrial production.

[0010] Promoting in-situ utilization and coupling processes: The ideal electrode should not only be able to produce ozone efficiently, but its structure or configuration should also be able to promote the efficient in-situ utilization of the generated ozone in the reactor (such as in conjunction with a catalyst), reduce mass transfer steps, and improve the overall oxidation efficiency, such as coupling with processes such as electro-Fenton.

[0011] In summary, current ozone technology, especially its application in the treatment of complex wastewater, urgently needs to develop a new anode material that has high oxygen evolution potential, excellent stability, long life, low cost, and can promote the efficient in-situ utilization of ozone, so as to break through the existing technological bottleneck and meet the growing demand for efficient and green water treatment. Summary of the Invention

[0012] The purpose of the present invention is to overcome the above-mentioned deficiencies of the prior art and to provide an ozone electrode coating material with a high oxygen evolution potential and its application.

[0013] The present invention is achieved in this way. In a first aspect, the present invention provides an ozone electrode coating material with a high oxygen evolution potential, the molecular formula of which is Ti / SnO2-Sb-TiO2, and which is prepared by the following method: Ti plate, SnCl4, SbCl3, and nano-TiO2 powder are selected as raw materials, SnCl4, SbCl3, and nano-TiO2 powder are dissolved in an organic solvent at a mass ratio of 100: (5-10): (0.5-2), and stirred until the solution is uniform to obtain a precursor solution; The Ti plate is coated and sintered using a precursor solution; wherein the coating and sintering treatment is to coat the precursor solution on the surface of the Ti plate and then send it for sintering, and then cool it to room temperature after taking it out; Repeat the coating and sintering processes for several times, anneal, and cool to room temperature to obtain the target product.

[0014] Preferably, the sintering conditions are: heating to 500-600° C. at a heating rate of 5-15° C. / min, and calcining at this temperature for 10-15 min.

[0015] Preferably, the coating and sintering processes are repeated 15 times.

[0016] Preferably, the annealing conditions are: annealing temperature 500-600° C., annealing time 1-2 h.

[0017] Preferably, the organic solvent is ethanol.

[0018] In a second aspect, the present invention provides an application of an ozone electrode coating material in an electro-Fenton-ozone catalytic oxidation coupled reaction device.

[0019] Preferably, the electro-Fenton-ozone catalytic oxidation coupled reaction device comprises an anode, a cathode, and an ozone catalyst arranged between the anode and the cathode; the anode adopts the above-mentioned ozone electrode coating material.

[0020] Preferably, the cathode is a carbon plate.

[0021] Preferably, the catalyst is foamed carbon.

[0022] Preferably, a porous insulating layer is provided between the anode and the ozone catalyst layer, and between the ozone catalyst layer and the cathode.

[0023] Preferably, the electro-Fenton-ozone catalytic oxidation coupled reaction device is used for wastewater treatment.

[0024] The beneficial effects of the present invention are at least: During the preparation process of the present invention, TiO2 nanoparticles are dispersed in a precursor solution. During the subsequent coating sintering, the TiO2 particles are surrounded by the SnO2 catalyst particles formed during sintering, forming a TiO2 / SnO2 nanoheterojunction at the microscopic level. The formation of the heterojunction causes the internal energy band to bend, forming a built-in electric field. This increases the oxygen evolution potential of the titanium anode electrode, which is mainly composed of tin oxide. This high oxygen evolution potential effectively suppresses the competitive oxygen evolution side reaction during water electrolysis, more efficiently directing the current to the target reaction - ozone generation, thereby significantly improving the electrode's electrooxidation performance and selectivity for ozone generation. At the same time, sintering and annealing at a temperature of 500-600°C can cause the nanoparticles to agglomerate due to reduced surface energy, forming a dense structure that hinders electrolyte penetration, thereby significantly improving the service life of the electrode. On the other hand, gentle sintering at 500-600°C allows the TiO2 nanoparticles to retain their nanomorphology in the electrode coating, possessing a high specific surface energy. At the same time, sintering closes some defects, reduces carrier scattering centers (grain boundaries), improves electron mobility (reduced grain boundary density), and reduces the electrode impedance, but the intrinsic conductivity remains low. Therefore, when sintered at 500-600°C, the performance of the electrocatalytic anode is comprehensively optimized through gentle grain growth, partial defect repair, and structural densification. In summary, the ozone electrode coating material of the present invention has a high oxygen evolution potential and a long service life, a simple preparation process, low cost, and is suitable for industrial production. It is expected to be widely used in the field of ozone catalytic oxidation.

[0025] Furthermore, the present invention utilizes the ozone electrode coating material as the anode for in-situ ozone generation during water electrolysis, improving ozone mass transfer efficiency. The generated ozone serves as its own ozone source, achieving self-sufficiency and completely avoiding the complex mass transfer steps (gas-liquid phase transfer) required by traditional methods to introduce ozone from an external gas phase. Ozone molecules generated at the anode instantly diffuse to the adjacent ozone catalyst layer, where they react promptly with the ozone catalyst within the reactor to produce hydroxyl radicals. Ozone is efficiently utilized near the point of generation, significantly increasing the local concentration and utilization of ozone and reducing ineffective escape and energy waste. Direct electrochemical oxidation at the anode, direct ozone oxidation, and ·OH oxidation generated by catalytic ozone oxidation occur simultaneously within the device, creating multiple, highly efficient oxidative degradation pathways. This revolutionizes the industry's challenges of low ozone mass transfer efficiency and utilization, enabling the efficient coupling of multiple advanced oxidation processes. This significantly improves the treatment efficiency of difficult-to-degrade organic wastewater and enhances the electrochemical reactor's capabilities for wastewater oxidation treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is the XRD pattern of Ti / SnO2-Sb-TiO2 prepared in Example 1 of the present invention.

[0028] Figure 2 This is the LSV curve of Ti / SnO2-Sb-TiO2 prepared in Example 1 of the present invention.

[0029] Figure 3 This is the ozone generation rate of Ti / SnO2-Sb-TiO2 prepared in Example 1 of the present invention in 10 minutes.

[0030] Figure 4 This is the accelerated life of the Ti / SnO2-Sb-TiO2 electrode prepared in Example 1 of the present invention.

[0031] Figure 5 Schematic diagram of an electrolytic high oxygen evolution electro-Fenton-ozone catalytic oxidation coupled reaction device prepared using Ti / SnO2-Sb-TiO2 as an anode in Example 1 of the present invention.

[0032] Figure 6 yes Figure 5 COD change diagram of the device degrading phenol.

[0033] Markings in the figure: 1. Anode; 2. Cathode; 3. Catalyst; 4. Isolation layer; 5. External protective shell of electrode material. DETAILED DESCRIPTION

[0034] To make the objectives, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0035] The embodiment of the present invention provides an ozone electrode coating material with a high oxygen evolution potential, the molecular formula of which is Ti / SnO2-Sb-TiO2, and is prepared by the following method: Ti plate, SnCl4, SbCl3, and nano-TiO2 powder are selected as raw materials, SnCl4, SbCl3, and nano-TiO2 powder are dissolved in an organic solvent at a mass ratio of 100: (5-10): (0.5-2), and stirred until the solution is uniform to obtain a precursor solution; The Ti plate is coated and sintered using a precursor solution; wherein the coating and sintering treatment is to coat the precursor solution on the surface of the Ti plate and then send it for sintering, and then cool it to room temperature after taking it out; Repeat the coating and sintering processes for several times, anneal, and cool to room temperature to obtain the target product.

[0036] In one embodiment, the sintering conditions are: heating to 500-600°C at a heating rate of 5-15°C / min, and calcining at this temperature for 10-15 minutes.

[0037] In one embodiment, the coating and sintering processes are repeated 15 times.

[0038] In one embodiment, the annealing conditions are: annealing temperature 500-600° C., annealing time 1-2 hours.

[0039] In one embodiment, the organic solvent is ethanol.

[0040] The embodiment of the present invention also provides the application of the ozone electrode coating material in an electro-Fenton-ozone catalytic oxidation coupled reaction device.

[0041] In one embodiment, the electro-Fenton-ozone catalytic oxidation coupled reaction device includes an anode, a cathode, and an ozone catalyst arranged between the anode and the cathode; the anode adopts the above-mentioned ozone electrode coating material.

[0042] In one embodiment, the cathode is a carbon plate, and the catalyst is foamed carbon.

[0043] In one embodiment, a porous insulating layer is further provided between the anode and the ozone catalyst layer, and between the ozone catalyst layer and the cathode.

[0044] In one embodiment, the electro-Fenton-ozone catalytic oxidation coupled reaction device is used for wastewater treatment.

[0045] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0046] Example 1 Preparation of Ti / SnO2-Sb-TiO2 anode by thermal decomposition method: Ti plate, SnCl4, SbCl3, nano-TiO2 powder and ethanol were selected as raw materials (the mass purity of each raw material was 99 wt%), the Ti plate was treated in boiling oxalic acid solution for 0.5 h, then removed and cleaned; SnCl4, SbCl3 and nano-TiO2 powder were dissolved in ethanol in a mass ratio of 100:6:1, and stirred with an ultrasonic stirrer until the solution was uniform; the obtained precursor solution was dipped into the solution with a small brush and gently coated on the treated surface of the Ti plate, and then placed in an oven for drying; the temperature was raised to 550°C in a muffle furnace at a rate of 10°C / min, kept at this temperature for 10 min, taken out and cooled to room temperature, and coated again; the above coating steps were repeated 15 times, annealed at 550°C in a muffle furnace for 1 h, cooled to room temperature, and the target product Ti / SnO2-Sb-TiO2 anode was obtained.

[0047] Product Characterization and Performance Testing The XRD pattern of the Ti / SnO2-Sb-TiO2 electrode coating sample prepared in Example 1 and the PDF standard card of TiO2 are shown in Figure 1 According to the shape of the diffraction peak, the existence of TiO2 phase can be confirmed in the XRD spectrum. The linear voltammetric curve of the Ti / SnO2-Sb-TiO2 electrode coating sample prepared in Example 1 is shown in FIG. Figure 2 .like Figure 2 As shown in Figure 2, after adding TiO2, the oxygen evolution potential of the electrode has been significantly improved to 2.3V, which is beneficial to inhibit the occurrence of oxygen evolution side reactions and improve the ozone generation efficiency. Figure 3 The accelerated life of the Ti / SnO2-Sb-TiO2 electrode coating sample prepared in Example 1 is shown in Figure 4 After adding TiO2, the life of the electrode increased by more than 5 times.

[0048] In summary, it is demonstrated that anatase TiO2-doped Ti / SnO2-Sb-TiO2 high oxygen evolution ozone anode material has been successfully prepared, which has good oxygen evolution potential and can produce high-purity ozone gas.

[0049] Application Example 1 The Ti / SnO2-Sb-TiO2 electrode coating sample prepared in Example 1 was used as the anode 1 to build an electrolytic high oxygen evolution electro-Fenton-ozone catalytic oxidation coupled reaction device. Figure 5 shown.

[0050] The electro-Fenton-ozone catalytic oxidation coupled reaction device includes an electrode material outer protective shell 5, and an anode 1, a cathode 2, an ozone catalyst layer 3, and a porous insulating layer 4 arranged in the electrode material outer protective shell 5.

[0051] Ozone catalyst layers 3 are provided on both sides of the anode 1, and cathodes 2 are provided outside the ozone catalyst layers 3 on both sides. Porous insulating layers 4 are provided to isolate the anode 1 from the ozone catalyst layers 3, the ozone catalyst layers 3 from the cathode 2, and the cathode 2 from the electrode material outer protective shell 5. This embodiment uses a carbon plate as the cathode 2, carbon foam as the ozone catalyst, and porous alumina ceramic as the material for the porous insulating layer 4.

[0052] This embodiment of the electro-Fenton-ozone catalytic oxidation coupled reaction device uses water electrolysis to generate ozone in situ, improving ozone mass transfer efficiency. The generated ozone can then react promptly with the ozone catalyst within the reactor to produce hydroxyl radicals. This allows for simultaneous electrochemical oxidation and ozone catalytic oxidation reactions within the electrochemical reactor, enhancing the reactor's ability to oxidize wastewater.

[0053] A porous insulating layer (4) is placed between the cathode, anode, and the ozone catalyst for ozone catalytic oxidation. The insulating layer has an air permeability of at least 90% and a thickness greater than 2 mm to prevent pH changes near the electrodes from affecting the efficiency of the ozone catalytic reaction. This layer also suppresses the oxygen evolution reaction (OER), allowing more current to be used for the oxidation of the target organic matter. The pores of the porous insulating layer can enrich dissolved or dissolved oxygen (O2), promoting its dehydration to form ·OH under the action of the electric field.

[0054] The anode utilizes a porous valve metal Ti plate substrate with a porosity of no less than 40% and a pore size no greater than 50 microns. This anode exhibits high stability and activity, enabling long-term catalytic degradation applications.

[0055] Product Characterization and Performance Testing The electrolytic high oxygen evolution electro-Fenton-ozone catalytic oxidation coupled reaction device assembled in Application Example 1 was used to degrade phenol solution, and its COD was tested using an ultraviolet spectrophotometer to reflect its degradation efficiency. Figure 6 As shown, the electrolytic high oxygen evolution electro-Fenton-ozone catalytic oxidation coupling technology of the present invention can achieve a COD removal rate of more than 95% within 2 hours as the current density increases.

[0056] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications are also considered to be within the scope of protection of the present invention.

Claims

1. An ozone electrode coating material with high oxygen evolution potential, molecular formula Ti / SnO2-Sb-TiO2, characterized by Prepared by the following method: Ti plate, SnCl4, SbCl3, and nano-TiO2 powder are selected as raw materials, SnCl4, SbCl3, and nano-TiO2 powder are dissolved in an organic solvent at a mass ratio of 100: (5-10): (0.5-2), and stirred until the solution is uniform to obtain a precursor solution; The Ti plate is coated and sintered using a precursor solution; wherein the coating and sintering treatment is to coat the precursor solution on the surface of the Ti plate and then send it for sintering, and then cool it to room temperature after taking it out; Repeat the coating and sintering processes for several times, anneal, and cool to room temperature to obtain the target product.

2. The ozone electrode coating material with high oxygen evolution potential according to claim 1, characterized in that: The sintering conditions are: heating to 500-600° C. at a heating rate of 5-15° C. / min, and calcining at the temperature for 10-15 minutes.

3. The ozone electrode coating material with high oxygen evolution potential according to claim 1, characterized in that: The coating and sintering processes were repeated 15 times.

4. The ozone electrode coating material with high oxygen evolution potential according to claim 1, characterized in that: The annealing conditions are: annealing temperature 500-600° C., annealing time 1-2 hours.

5. The ozone electrode coating material with high oxygen evolution potential according to claim 1, characterized in that: The organic solvent is ethanol.

6. Use of the ozone electrode coating material with a high oxygen evolution potential according to any one of claims 1 to 5 in an electro-Fenton-ozone catalytic oxidation coupled reaction device.

7. The application according to claim 6, characterized in that The electro-Fenton-ozone catalytic oxidation coupled reaction device comprises an anode, a cathode, and an ozone catalyst arranged between the anode and the cathode; the anode adopts an ozone electrode coating material with a high oxygen evolution potential as described in any one of claims 1-5.

8. The application according to claim 7, characterized in that: The cathode is made of a carbon plate, and the catalyst is made of foam carbon.

9. The application according to claim 8, characterized in that: A porous insulating layer is further provided between the anode and the ozone catalyst layer, and between the ozone catalyst layer and the cathode.

10. The use according to claims 6-9, characterized in that: The electro-Fenton-ozone catalytic oxidation coupled reaction device is used for wastewater treatment.

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