Titanium-based composite anode, preparation method and application of the titanium-based composite anode in electrochemical synthesis of adiponitrile

Abstract

The present application relates to the field of electrochemical organic synthesis, and particularly relates to a titanium-based composite anode, a preparation method and application of the titanium-based composite anode in electrochemical synthesis of adiponitrile, the titanium-based composite anode comprises a titanium base material, and from inside to outside on the surface of the titanium base material, there are an indium tin oxide bottom layer, a tin antimony oxide intermediate layer and a doped active layer. The indium tin oxide bottom layer is deposited on the surface of the titanium base material, the tin antimony oxide intermediate layer is prepared on the indium tin oxide bottom layer, and the doped active layer is prepared on the intermediate layer. In the electrochemical synthesis of adiponitrile, the titanium-based composite anode is used as an anode. The titanium-based composite anode improves the adhesion between the doped active layer and the base material, improves the conductivity, and improves the corrosion resistance. In the electrochemical synthesis of adiponitrile, the problem of easy corrosion of the anode in electrolysis is solved, the service life is improved, and the yield of adiponitrile and the electrolytic current efficiency are improved.

Description

Technical Field

[0001] This invention relates to the field of electrochemical organic synthesis, specifically to titanium-based composite anodes, their preparation methods, and their application in the electrochemical synthesis of adiponitrile. Background Technology

[0002] Adiponitrile (ADN) is an important chemical product, an intermediate in the manufacture of nylon 66, and also used as an additive in rubber production, a high-grade paint, an extractant for aromatic hydrocarbon extraction, and a herbicide. Industrially, ADN synthesis methods mainly include acrylonitrile electroreduction, butadiene hydrocyanation, and adipic acid ammoniation dehydration. However, compared with traditional organic synthesis methods, electrochemical organic synthesis has advantages such as easy reaction control, inexpensive and readily available raw materials, high product purity, fewer byproducts, less environmental pollution, shorter process chain, and lower equipment investment. Therefore, electrochemical organic synthesis of ADN is bound to become the mainstream technology in the industry in the future.

[0003] Currently, lead alloys, stainless steel, and carbon steel are the mainstream anode materials used in electrochemical organic synthesis (ADN). However, lead alloys, stainless steel, and carbon steel suffer from drawbacks during production, such as easy corrosion and anode dissolution leading to poor cathode product quality. Therefore, researchers have explored the use of titanium anodes for electrochemical organic synthesis of target products. Titanium-based lead dioxide electrodes are currently recognized as having significant advantages. When electrolyzed in aqueous solution, titanium-based lead dioxide electrodes exhibit good corrosion resistance, high conductivity, and the ability to handle large currents, making them suitable for the field of electrochemical organic synthesis. Although traditional titanium-based lead dioxide electrodes possess many of these advantages, they still have certain drawbacks, such as high cell voltage during electrolysis, short service life under organic system conditions, and low adhesion and easy peeling of the PbO2 coating on the titanium substrate. Therefore, the development of novel titanium-based composite anodes has become one of the research hotspots in the field of electrochemical organic synthesis. Summary of the Invention

[0004] The purpose of this invention is to provide a titanium-based composite anode and its preparation method, which can be used as an anode for the electrochemical synthesis of adiponitrile. By adding an indium tin oxide underlayer and a tin-antimony oxide intermediate layer, the adhesion between the PbO2 coating and the substrate is improved, conductivity is increased, the anode working tank voltage is reduced, and service life is extended.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A titanium-based composite anode includes a titanium substrate, on the surface of which, from the inside out, are an indium tin oxide underlayer, a tin-antimony oxide intermediate layer, and a doped active layer.

[0006] Preferably, the doped active layer is manganese cobalt oxide doped lead dioxide (PbO2-MnCo2O4).

[0007] Preferably, the thickness of the indium tin oxide underlayer is 1-5 μm.

[0008] The present invention also provides a method for preparing the above-mentioned titanium-based composite anode, comprising the following steps: 1) Perform surface treatment on the titanium substrate; 2) Deposit an indium tin oxide underlayer on the surface of a titanium substrate; 3) Prepare an antimony tin oxide intermediate layer on an indium tin oxide substrate; 4) Using the titanium substrate prepared in step 3) as the anode and the pure titanium substrate as the cathode, a doped active layer is prepared by anodic oxidation electrodeposition in a nitric acid deposition solution system containing MnCo2O4.

[0009] Preferably, in step 1), a laser is used to treat the surface of the titanium substrate to make the surface of the titanium substrate uniform and free of oxide scale.

[0010] Preferably, in step 2), an indium tin oxide underlayer is prepared by vacuum deposition, wherein the vacuum deposition method is vacuum evaporation or magnetron sputtering.

[0011] Preferably, in step 3), a tin-antimony intermediate layer is prepared by spraying a tin-antimony intermediate layer precursor; wherein, the spraying is repeated once, followed by sintering, and the spraying and sintering are repeated multiple times until the required thickness of the tin-antimony intermediate layer is achieved.

[0012] Preferably, in step 3), the tin-antimony intermediate layer precursor is a n-butanol solution with a tin-antimony molar ratio of 20:1, the sintering temperature is 500℃, and the holding time is 15min.

[0013] Preferably, the spraying method is ultrasonic spraying or two-fluid spraying.

[0014] Preferably, in step 4) anodic oxidation electrodeposition: a nitric acid deposition solution system containing MnCo2O4 is used as the electrolyte, and the MnCo2O4 nitric acid deposition solution system is a mixed solution of lead nitrate and copper nitrate containing MnCo2O4. At a temperature of 30~70℃, the titanium substrate prepared in step 3) is used as the anode, and a pure titanium substrate is used as the cathode. Electrodeposition is performed for 2~8 h, and the electrodeposition current density is 150~300 A / m. 2 .

[0015] Preferably, the nitric acid precipitation solution system containing MnCo2O4 is prepared with deionized water, which contains 140~180 g / Lb. 2+ 15~30 g / L Cu 2+ 6 g / L MnCo2O4.

[0016] This invention also provides the application of titanium-based composite anodes as anodes in the electrochemical synthesis of adiponitrile.

[0017] Preferably, when the titanium-based composite anode is used as the anode for the electrochemical synthesis of adiponitrile, the lead substrate is used as the cathode, and the current density for the electrochemical synthesis of adiponitrile is 1500 A / m. 2 .

[0018] Preferably, in the electrochemical synthesis system of adiponitrile, the electrolyte contains 2%-7% acrylonitrile, 10%-20% potassium phosphate as a supporting electrolyte, 0.5-2% sodium EDTA as a buffer for the pH value of the electrolyte, 1.0%-8.0% quaternary ammonium salt as a directed ion source, and the remainder is water. The pH value of the electrolyte is adjusted to the range of 6-10 with phosphoric acid or a strong base, and the concentration of each substance in the electrolyte is a mass percentage concentration.

[0019] Compared with the prior art, the beneficial effects of this invention are as follows: This invention relates to a titanium-based composite anode for the electrochemical synthesis of adiponitrile. From the inside out, the anode consists of a titanium substrate (Ti), an indium tin oxide (ITO) underlayer, an antimony tin oxide (ATO) interlayer, and a doped active layer (PbO2-MnCo2O4). The ITO underlayer serves two main purposes: first, excellent electrical conductivity; and second, forming a solid solution with the interlayer to improve adhesion. The ATO interlayer also serves two main purposes: first, improving the adhesion between the PbO2 coating and the substrate; and second, preventing corrosion and passivation of the titanium substrate. The doped active layer primarily enhances the oxygen evolution activity of the anode active layer, thereby reducing the working tank pressure. This titanium-based composite anode improves the conductivity and service life of the anode product. Furthermore, the use of a robotic process instead of manual coating significantly improves the consistency of the anode product, reduces worker workload, and features a simple and easily implemented process, facilitating industrial production and cost savings.

[0020] Laser cleaning machine is used to treat the oxide scale of titanium substrate, replacing the traditional sandblasting and pickling process, which is simple and practical. For the first time, vacuum deposition is introduced into the electrode to prepare the ITO underlayer, which greatly improves the conductivity. Tin oxide antimony intermediate layer is prepared by spraying technology, which has good uniformity and facilitates quantitative control of the loading.

[0021] The prepared titanium-based composite anode was applied to the electrochemical synthesis of adiponitrile, which solved the problem of easy corrosion of the anode in electrolysis, improved its service life, and simultaneously improved the yield of adiponitrile and the efficiency of electrolysis current. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of one side of the titanium-based composite anode structure. Detailed Implementation

[0023] The titanium-based composite anode of the present invention, see [reference]. Figure 1The substrate comprises a titanium base 1, on the surface of which, from the inside out, are an indium tin oxide (ITO) underlayer 2, an antimony tin oxide (ATO) intermediate layer 3, and a doped active layer 4. The doped active layer is manganese cobalt oxide-doped lead dioxide (PbO2-MnCo2O4). The thickness of the indium tin oxide underlayer is 1-5 μm.

[0024] The method for preparing the titanium-based composite anode of the present invention includes the following steps: 1) Surface pretreatment of titanium substrate: Laser treatment is performed on the titanium substrate to form a uniform surface free of oxide scale; 2) An indium tin oxide (ITO) underlayer is prepared on the laser-treated titanium substrate in step 1) using a vacuum deposition method; the ITO underlayer thickness ranges from 1 to 5 μm. 3) Spray the titanium substrate prepared in step 2) with tin-antimony intermediate layer precursor, and sinter to prepare tin-antimony oxide intermediate layer.

[0025] 4) Using the titanium substrate prepared in step 3) as the anode and the pure titanium substrate as the cathode, a titanium-based composite anode (PbO2-MnCo2O4) is prepared by electrodepositing an active layer in a nitric acid deposition solution system containing MnCo2O4.

[0026] The specific process for preparing the indium tin oxide underlayer using the vacuum deposition method in step 2) is as follows: vacuum deposition is performed using either vacuum evaporation or magnetron sputtering. Wherein: The vacuum evaporation process involves evaporating indium-tin alloy using a resistance-heated quartz glass boat. The heating temperature of the evaporation source is 800-1000℃, oxygen is used as the reactant gas, and the system vacuum level is 10. -3 Pa, the distance from the evaporation source to the titanium sheet is 20-25 cm.

[0027] The magnetron sputtering process is as follows: DC magnetron sputtering of ITO target material in an argon atmosphere, with argon gas pressure of 0.2-3 Pa, DC sputtering current of 80-120 mA, and DC sputtering voltage of 200-320 V.

[0028] The specific process for step 3) is as follows: The titanium substrate prepared in step 2) is sprayed with a tin-antimony intermediate layer precursor, and then sintered to prepare a tin-antimony oxide intermediate layer. The tin-antimony intermediate layer precursor is a n-butanol solution with a tin (Sn):antimony (Sb) molar ratio of 20:1. The tin-antimony intermediate layer precursor solution is coated using a spraying technique, with one coat followed by one sintering. The sintering temperature is 500℃, and the holding time is 15min. The spraying and sintering are repeated multiple times, generally 5 times, depending on the designed thickness of the tin-antimony oxide intermediate layer.

[0029] The spraying method is: ultrasonic spraying or two-fluid spraying, wherein: The specific process parameters for ultrasonic spraying are as follows: carrier gas pressure 30Pa, working speed 5400mm / min-12000mm / min, rapid traverse speed 5000mm / min, spray width 7.0mm, and liquid supply flow rate 1.0mL / min-3.0mL / min.

[0030] The process parameters for two-fluid spraying are: compressed air pressure of 50 Pa, working speed of 2000 mm / min-3000 mm / min, spray width of 20.0 mm, and liquid supply flow rate of 10.0 mL / min-30.0 mL / min.

[0031] The specific process of step 4) is as follows: Prepare a mixed solution of lead nitrate and copper nitrate containing MnCo2O4 in an electrolytic cell, heat it to 30~70℃, and stir it evenly. Then fix the titanium substrate anode and pure titanium substrate cathode prepared in step 3) in the electrolytic cell, respectively, and perform electrodeposition for 2~8 h. The electrodeposition current density is 150~300 A / m 2 .

[0032] The nitric acid precipitation solution system was prepared using deionized water, which contained 140–180 g / L Pb. 2+ 15~30 g / L Cu 2 + 6 g / L MnCo2O4.

[0033] MnCo2O4 was prepared by reacting a mixed solution of 0.2M manganese sulfate and 0.12M cobalt nitrate with 0.15M sodium persulfate. The pH was adjusted to 10 with ammonia water, and the reaction was carried out in a water bath for 30 min. After centrifugation and washing with water, the mixture was vacuum dried and sintered at 350℃ for 3 h.

[0034] The titanium-based composite anode prepared according to the above method was used as the anode for the electrochemical synthesis of adiponitrile, and a lead substrate was used as the cathode. The anode was fixed in the electrolytic cell, and an electrochemical synthesis current density of 1500 A / m was applied. 2 .

[0035] In the electrochemical synthesis system of adiponitrile, the electrolyte contains 2%-7% acrylonitrile, 10%-20% potassium phosphate as a supporting electrolyte, 0.5%-2% sodium EDTA as a buffer for the electrolyte pH, 1.0%-8.0% quaternary ammonium salt as a directing ion source, and the remainder is water. The pH of the electrolyte is adjusted to the range of 6-10 using phosphoric acid or a strong base. The concentrations of each substance in the electrolyte are mass percentages.

[0036] Regarding the above technical solution, several preferred embodiments are described in detail below.

[0037] Example 1

[0038] The preparation method of titanium-based composite anode includes the following steps: 1) Use a handheld laser cleaning machine to treat the surface of the titanium substrate, remove the surface oxide scale, and make the surface of the titanium substrate uniform.

[0039] 2) The titanium substrate treated by laser in step 1) is used to prepare an indium tin oxide (ITO) underlayer using vacuum evaporation. An ITO alloy is evaporated using a quartz glass boat heated by resistance heating. The heating temperature of the evaporation source is 800℃, oxygen is used as the reactant gas, and the system vacuum degree is 10. -3 Pa, the distance from the evaporation source to the titanium sheet is 25 cm, and the thickness of the ITO underlayer prepared by vacuum evaporation is 1 μm.

[0040] 3) Spray the titanium substrate prepared in step 2) with a tin-antimony intermediate layer precursor, and sinter to prepare an ATO tin-antimony oxide intermediate layer. The tin-antimony intermediate layer precursor is a n-butanol solution with a Sn:Sb molar ratio of 20:1. The tin-antimony intermediate layer precursor solution is coated with ultrasonic spraying technology. One spraying and one sintering are performed. The sintering temperature is 500℃ and the holding time is 15min. The spraying and sintering are repeated 5 times. The specific process parameters for ultrasonic spraying are as follows: carrier gas pressure 30Pa, working speed 5400mm / min, rapid traverse speed 5000 mm / min, spray width 7.0mm, and liquid supply flow rate 1.0mL / min.

[0041] 4) Using the titanium substrate prepared in step 3) as the anode and the pure titanium substrate as the cathode, a titanium-based composite anode (PbO2-MnCo2O4) is prepared by electrodepositing an active layer in a nitric acid deposition solution system containing MnCo2O4: The nitric acid precipitation solution system containing MnCo2O4 was prepared in an electrolytic cell as a mixed solution of lead nitrate and copper nitrate containing MnCo2O4, which contained 140 g / L Pb. 2+ 15 g / L Cu 2+ Add 6 g / L MnCo2O4 and heat to 30℃, stirring until homogeneous; Subsequently, the titanium substrate anode and the pure titanium substrate cathode prepared in step 3) were respectively fixed in the electrolytic cell, and electrodeposition was carried out for 2 h with an electrodeposition current density of 150 A / m. 2 A PbO2-MnCo2O4 doped active layer is formed on the titanium substrate prepared in step 3).

[0042] The above-mentioned MnCo2O4 was prepared by reacting a mixed solution of 0.2M manganese sulfate and 0.12M cobalt nitrate with 0.15M sodium persulfate, adjusting the pH to 10 with ammonia, reacting in a water bath for 30 min, centrifuging and washing with water, vacuum drying, and sintering at 350℃ for 3 h.

[0043] The above preparation method can yield titanium-based composite anode material Ti / ITO / ATO / PbO2-MnCo2O4 with excellent conductivity and long lifespan.

[0044] The titanium-based composite anode prepared in steps 1) to 4) above was used for the electrochemical synthesis of adiponitrile. Specific operating procedures: The titanium-based composite anode (Ti / ITO / ATO / PbO2-MnCo2O4) and the lead-based cathode were respectively fixed in an electrolytic cell, and an electrochemical synthesis current density of 1500 A / m was applied. 2 .

[0045] The electrolyte in the electrochemical synthesis system of adiponitrile contains: 2% acrylonitrile, 10% potassium phosphate as a supporting electrolyte, 0.5% sodium EDTA as a buffer for electrolyte pH, 1% quaternary ammonium salt as a directing ion source, and the remainder is water. The pH of the electrolyte is adjusted to 6 with phosphoric acid or a strong base. The concentrations of each substance in the electrolyte are mass percentages.

[0046] The above-mentioned Ti / ITO / ATO / PbO2-MnCo2O4 anodic electrochemical synthesis of adiponitrile solves the disadvantage of easy corrosion of the anode in electrolysis, and at the same time achieves an adiponitrile yield of over 85% and a current efficiency of over 80%.

[0047] Example 2

[0048] The method for preparing the titanium-based composite anode of the present invention includes the following steps: 1) Use a handheld laser cleaning machine to treat the surface of the titanium substrate, remove the surface oxide scale, and make the surface of the titanium substrate uniform.

[0049] 2) The titanium substrate treated by laser in step 1) is used to prepare indium tin oxide underlayer by magnetron sputtering. The ITO underlayer is prepared by DC magnetron sputtering of ITO target material in argon atmosphere. The sputtering gas argon pressure is 2 Pa, DC sputtering current is 100 mA, DC sputtering voltage is 250 V, and the thickness of the underlayer prepared by vacuum deposition is 3 μm.

[0050] 3) Spray the titanium substrate prepared in step 2) with a tin-antimony intermediate layer precursor and sinter to prepare an ATO intermediate layer. The tin-antimony intermediate layer precursor is a n-butanol solution with a Sn:Sb molar ratio of 20:1. The intermediate layer precursor solution is coated with a two-fluid spraying technique. One spraying and one sintering are performed. The sintering temperature is 500℃ and the holding time is 15min. The spraying and sintering are repeated 5 times. The specific process parameters for the two-fluid spraying are: carrier gas pressure 50Pa, working speed 2000mm / min, spraying width 20.0mm, and liquid supply flow rate 20.0mL / min.

[0051] 4) Using the titanium substrate prepared in step 3) as the anode and the pure titanium substrate as the cathode, a titanium-based composite anode (PbO2-MnCo2O4) is prepared by electrodepositing an active layer in a nitric acid deposition solution system containing MnCo2O4: The nitric acid precipitation solution system containing MnCo2O4 is as follows: a mixed solution of lead nitrate and copper nitrate containing MnCo2O4 is prepared in an electrolytic cell, containing 160 g / L Pb. 2+ 20 g / L Cu 2+ Add 6 g / L MnCo2O4 and heat to 30℃, stirring until homogeneous; Subsequently, the titanium substrate anode and the pure titanium substrate cathode prepared in step 3) were respectively fixed in the electrolytic cell, and electrodeposition was carried out for 6 hours at an electrodeposition current density of 200 A / m. 2 .

[0052] The above-mentioned MnCo2O4 was prepared by reacting a mixed solution of 0.2M manganese sulfate and 0.12M cobalt nitrate with 0.15M sodium persulfate, adjusting the pH to 10 with ammonia, reacting in a water bath for 30 min, centrifuging and washing with water, vacuum drying, and sintering at 350℃ for 3 h.

[0053] The above preparation process can yield titanium-based composite anode material Ti / ITO / ATO / PbO2-MnCo2O4 with excellent conductivity and long lifespan.

[0054] The titanium-based composite anode prepared in steps 1) to 4) above was used for the electrochemical synthesis of adiponitrile. Specific operating procedures: The titanium-based composite anode (Ti / ITO / ATO / PbO2-MnCo2O4) and the lead-based cathode were respectively fixed in an electrolytic cell, and an electrochemical synthesis current density of 1500 A / m was applied. 2 .

[0055] The electrolyte in the electrochemical synthesis system of adiponitrile contains: 5% acrylonitrile, 15% potassium phosphate as a supporting electrolyte, 1% sodium EDTA as a buffer for electrolyte pH, 5% quaternary ammonium salt as a directed ion source, and the remainder is water. The pH of the electrolyte is adjusted to 8 with phosphoric acid or a strong base. The concentrations of each substance in the electrolyte are mass percentages.

[0056] The above-mentioned Ti / ITO / ATO / PbO2-MnCo2O4 anode was used for the electrochemical synthesis of adiponitrile, which solved the disadvantage of easy corrosion of the anode in electrolysis, and achieved an adiponitrile yield of 87% and a current efficiency of 82%.

[0057] Example 3

[0058] The method for preparing the titanium-based composite anode of the present invention includes the following steps: 1) Use a handheld laser cleaning machine to treat the surface of the titanium substrate, remove the surface oxide scale, and make the surface of the titanium substrate uniform.

[0059] 2) The titanium substrate treated by laser in step 1) is used to prepare indium tin oxide (ITO) underlayer by magnetron sputtering. The magnetron sputtering process parameters are as follows: ITO underlayer is prepared by DC magnetron sputtering of ITO target in argon atmosphere, argon gas pressure is 3.0 Pa, DC sputtering current is 120 mA, DC sputtering voltage is 3200 V, and the thickness of the underlayer prepared by vacuum deposition is 5 μm.

[0060] 3) Spray the titanium substrate prepared in step 2) with a tin-antimony intermediate layer precursor and sinter it to prepare an ATO intermediate layer. The tin-antimony intermediate layer precursor is a n-butanol solution with a Sn:Sb molar ratio of 20:1. The intermediate layer precursor solution is coated with ultrasonic spraying technology. Spray once and sinter once. The sintering temperature is 500℃ and the holding time is 15min. Repeat the spraying and sintering process 5 times.

[0061] The specific process parameters for ultrasonic spraying are as follows: carrier gas pressure 30Pa, working speed 12000mm / min, rapid traverse speed 5000 mm / min, spray width 7.0mm, and liquid supply flow rate 3.0mL / min.

[0062] 4) Using the titanium substrate prepared in step 3) as the anode and the pure titanium substrate as the cathode, a titanium-based composite anode (PbO2-MnCo2O4) is prepared by electrodepositing an active layer in a nitric acid deposition solution system containing MnCo2O4: The nitric acid precipitation solution system containing MnCo2O4 is as follows: a mixed solution of lead nitrate and copper nitrate containing MnCo2O4 is prepared in an electrolytic cell, containing 180 g / L Pb. 2+ 30 g / L Cu 2+ Add 6 g / L MnCo2O4 and heat to 30℃, stirring until homogeneous; Subsequently, the titanium substrate anode and the pure titanium substrate cathode prepared in step 3) were respectively fixed in the electrolytic cell, and electrodeposition was carried out for 8 h with an electrodeposition current density of 300 A / m. 2 .

[0063] The above-mentioned MnCo2O4 was prepared by reacting a mixed solution of 0.2M manganese sulfate and 0.12M cobalt nitrate with 0.15M sodium persulfate, adjusting the pH to 10 with ammonia, reacting in a water bath for 30 min, centrifuging and washing with water, vacuum drying, and sintering at 350℃ for 3 h.

[0064] The above preparation process can yield anode material Ti / ITO / ATO / PbO2-MnCo2O4 with excellent conductivity and long lifespan.

[0065] The titanium-based composite anode prepared in steps 1) to 4) above was used for the electrochemical synthesis of adiponitrile. Specific operating procedures: The titanium-based composite anode (Ti / ITO / ATO / PbO2-MnCo2O4) and the lead-based cathode were respectively fixed in an electrolytic cell, and an electrochemical synthesis current density of 1500 A / m was applied. 2 .

[0066] The electrolyte in the electrochemical synthesis system of adiponitrile contains: 7% acrylonitrile, 20% potassium phosphate as a supporting electrolyte, 2% sodium EDTA as a buffer for electrolyte pH, 8% quaternary ammonium salt as a directed ion source, and the remainder is water. The pH of the electrolyte is adjusted to 10 with phosphoric acid or a strong base. The concentrations of each substance in the electrolyte are mass percentages.

[0067] The above-mentioned Ti / ITO / ATO / PbO2-MnCo2O4 anode was used for the electrochemical synthesis of adiponitrile, which solved the disadvantage of easy corrosion of the anode in electrolysis, and achieved an adiponitrile yield of 86% and a current efficiency of 81%.

[0068] The titanium-based composite anode of this invention improves conductivity by adding an ITO underlayer, which strengthens the bond with the intermediate layer; by adding a tin-antimony oxide intermediate layer, it improves the bond between the PbO2 coating and the substrate while preventing substrate corrosion and passivation; the doped active layer is mainly to improve the oxygen evolution activity of the anode active layer, thereby reducing the anode working tank pressure. Therefore, the titanium-based composite anode has good conductivity and a long service life.

Claims

1. A titanium-based composite anode, characterized in that, The material includes a titanium substrate, on the surface of which, from the inside out, are an indium tin oxide bottom layer, a tin-antimony oxide intermediate layer, and a doped active layer; the doped active layer is manganese cobalt oxide doped lead dioxide.

2. The titanium-based composite anode according to claim 1, characterized in that, The thickness of the indium tin oxide underlayer is 1-5 μm.

3. A method for preparing the titanium-based composite anode according to any one of claims 1 to 2, comprising the following steps: 1) Perform surface treatment on the titanium substrate; 2) Deposit an indium tin oxide underlayer on the surface of a titanium substrate; 3) Prepare an antimony tin oxide intermediate layer on an indium tin oxide substrate; 4) Using the titanium substrate prepared in step 3) as the anode and the pure titanium substrate as the cathode, a doped active layer is prepared by anodic oxidation electrodeposition in a nitric acid deposition solution system containing MnCo2O4.

4. The preparation method according to claim 3, characterized in that, In step 1), a laser is used to treat the surface of the titanium substrate to make the surface of the titanium substrate uniform and free of oxide scale.

5. The preparation method according to claim 3, characterized in that, In step 2), an indium tin oxide underlayer is prepared by vacuum deposition.

6. The preparation method according to claim 3, characterized in that, In step 3), a tin-antimony oxide intermediate layer is prepared by spraying a tin-antimony intermediate layer precursor; wherein, the spraying is repeated once, followed by sintering, and the spraying and sintering are repeated multiple times until the required thickness of the tin-antimony oxide intermediate layer is achieved.

7. The preparation method according to claim 6, characterized in that, In step 3), the tin-antimony intermediate layer precursor is a n-butanol solution with a tin-antimony molar ratio of 20:1, the sintering temperature is 500℃, and the holding time is 15min.

8. The preparation method according to claim 3, characterized in that, Step 4) Anodizing electrodeposition: A nitric acid deposition solution system containing MnCo₂O₄ is used as the electrolyte. The MnCo₂O₄ nitric acid deposition solution system is a mixed solution of lead nitrate and copper nitrate containing MnCo₂O₄. At a temperature of 30–70°C, the titanium substrate prepared in step 3) is used as the anode, and a pure titanium substrate is used as the cathode. Electrodeposition is performed for 2–8 hours at a current density of 150–300 A / m. 2 .

9. The preparation method according to claim 8, characterized in that, The nitric acid precipitation solution system containing MnCo2O4 was prepared using deionized water, which contained 140–180 g / L Pb. 2+ 15~30 g / L Cu 2+ 6 g / L MnCo2O4.

10. The application of the titanium-based composite anode according to any one of claims 1 to 2 as an anode in the electrochemical synthesis of adiponitrile.

11. The application according to claim 10, characterized in that, The cathode is a lead substrate, and the current density for the electrochemical synthesis of adiponitrile is 1500 A / m. 2 .

12. The application according to claim 11, characterized in that, In the electrochemical synthesis system of adiponitrile, the electrolyte contains 2%-7% acrylonitrile, 10%-20% potassium phosphate as a supporting electrolyte, 0.5-2% sodium EDTA as a buffer for the pH value of the electrolyte, 1.0%-8.0% quaternary ammonium salt as a directed ion source, and the remainder is water. The pH value of the electrolyte is adjusted to the range of 6-10 with phosphoric acid or a strong base. The concentrations of each substance in the electrolyte are mass percentage concentrations.

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