Electrode material and preparation method and application thereof

Abstract

The invention belongs to the technical field of electrocatalytic oxidation, and particularly relates to an electrode material and a preparation method and application thereof. The electrode material provided by the invention comprises a substrate, an alpha-PbO2 layer and an active layer which are stacked in sequence, the active layer is prepared from beta-PbO2, nano thulium oxide and cocamidopropyl dimethylamine oxide, and the nano thulium oxide and the cocamidopropyl dimethylamine oxide are doped in the beta-PbO2. According to the invention, cocamidopropyl dimethylamine oxide and nano thulium oxide doped in beta-PbO2 reduce the interaction between an electrode interface and an electro-deposition solution and control the exposure condition of a crystal face, so that the surface of the electrode is not easy to exchange with an electrolyte interface, and discharge of water and protons is inhibited; and the generation speed of hydroxyl radicals is slower than the surface diffusion speed of sediments, so that the oxygen evolution potential is improved, the chlorine evolution potential is reduced, and the current efficiency of electrocatalytic oxidation is improved.

Description

Technical Field

[0001] This invention belongs to the field of electrocatalytic oxidation technology, specifically relating to an electrode material, its preparation method, and its application. Background Technology

[0002] Electrocatalytic oxidation technology, as a pollution-free and highly efficient oxidation technology, is widely used in wastewater treatment. It can effectively degrade organic matter, especially recalcitrant and toxic substances. Furthermore, this technology can simultaneously remove heavy metal ions and harmful substances such as nitrogen and phosphorus from wastewater.

[0003] The choice of anode material affects the efficiency of electrocatalytic oxidation reaction. Most existing anode materials are lead dioxide electroplated on the surface of titanium substrate. However, the bonding force between lead dioxide and titanium substrate is poor, which makes lead dioxide easy to fall off. In addition, lead dioxide electrode impedance is high and conductivity is insufficient. The oxygen evolution overpotential of existing anode materials is low, which affects the current efficiency of electrocatalytic oxidation. Summary of the Invention

[0004] In view of this, the present invention provides an electrode material, its preparation method and application. The electrode material provided by the present invention has a high oxygen evolution overpotential and can significantly improve the current efficiency of electrocatalytic oxidation.

[0005] To address the aforementioned technical problems, the present invention provides an electrode material comprising a matrix, an α-PbO2 layer, and an active layer stacked sequentially.

[0006] The active layer is β-PbO2 and nano-thulium oxide and cocamidopropylamine oxide doped in the β-PbO2.

[0007] Preferably, the thickness of the active layer is 20–25 μm;

[0008] The total mass percentage of nano-thulium oxide and cocamidopropylamine oxide in the active layer is 2.8–6.9%.

[0009] The mass ratio of the nano-thulium oxide to cocamidopropylamine oxide is 1:1 to 2.

[0010] Preferably, the thickness of the α-PbO2 layer is 10–13 μm.

[0011] Preferably, the substrate comprises aluminum mesh, titanium mesh, or stainless steel mesh.

[0012] The present invention also provides a method for preparing the electrode material described in the above technical solution, comprising the following steps:

[0013] A first electrodeposition is performed on the substrate surface to obtain an α-PbO2 layer; the electroplating solution used for the first electrodeposition is an alkaline solution of lead oxide;

[0014] A second electrodeposition is performed on the surface of the α-PbO2 layer to obtain the electrode material; the electroplating solution for the second electrodeposition is a mixed solution of lead nitrate, nano-thulium oxide, cocamidopropylamine oxide, nitric acid and sodium fluoride.

[0015] Preferably, before the first electrodeposition, the method further includes: immersing the substrate material in an acidic solution for etching;

[0016] The acidic solution includes hydrofluoric acid or methanesulfonic acid; the mass concentration of the acidic solution is 8-12%.

[0017] The soaking temperature is 85-95℃, and the soaking time is 10-30 minutes.

[0018] Preferably, the alkaline solution of lead oxide includes lead oxide and an alkaline substance, wherein the molar concentration of lead oxide is 0.1 to 0.5 mol / L and the molar concentration of the alkaline substance is 3 to 4 mol / L.

[0019] The first electrodeposition temperature is 15–50°C, and the current density is 10–30 mA / cm². 2 The time is 30 to 60 minutes.

[0020] Preferably, the molar concentration of lead nitrate in the second electrodeposition electroplating solution is 0.1–0.5 mol / L, the molar concentration of nitric acid is 0.08–0.12 mol / L, the molar concentration of sodium fluoride is 1–4 mmol / L, the molar concentration of cocamidopropylamine oxide is 1–4 mol / L, and the mass concentration of nano-thulium oxide is 0.5–3 g / L.

[0021] Preferably, the temperature for the second electrodeposition is 58–62°C, and the current density is 30–60 mA / cm². 2 The time is 60 to 120 minutes.

[0022] The present invention also provides the application of the electrode material described in the above technical solution or the electrode material prepared by the preparation method described in the above technical solution as an anode material for electrocatalytic oxidation.

[0023] This invention provides an electrode material comprising a matrix, an α-PbO2 layer, and an active layer stacked sequentially; the active layer is β-PbO2 and nano-thulium oxide and cocamidopropylamine oxide doped in the β-PbO2. The nano-thulium oxide and cocamidopropylamine oxide in the active layer of the electrode material provided by this invention enhance the adhesion between the intermediate layer and the active layer, improve the stability of the active layer, and reduce the risk of the active layer easily detaching. In this invention, the cocamidopropylamine oxide and nano-thulium oxide doped in β-PbO2 reduce the interaction between the electrode interface and the electrodeposition solution, control the exposure of the crystal facets, make it difficult for the electrode surface to exchange with the electrolyte interface, suppress the discharge of water and protons, and slow down the generation rate of hydroxyl radicals compared to the surface diffusion of the deposit, thereby increasing the oxygen evolution potential and reducing the chlorine evolution potential, and thus improving the current efficiency of electrocatalytic oxidation. Attached Figure Description

[0024] Figure 1 This is a physical image of the electrode material prepared in Comparative Example 1;

[0025] Figure 2 Here is a photograph of the electrode material prepared in Example 4;

[0026] Figure 3 SEM image of the electrode material prepared in Comparative Example 1;

[0027] Figure 4 SEM image of the electrode material prepared in Example 4;

[0028] Figure 5 This is a comparison of the oxygen evolution curves of the electrode materials prepared in Example 4 and Comparative Example 1;

[0029] Figure 6 The graph shows a comparison of the chlorine evolution curves of the electrode materials prepared in Example 4 and Comparative Example 1. Detailed Implementation

[0030] The present invention provides an electrode material comprising a matrix, an α-PbO2 layer and an active layer stacked sequentially.

[0031] The electrode material provided by this invention includes a substrate. In this invention, the substrate preferably comprises an aluminum mesh, a titanium mesh, or a stainless steel mesh, more preferably an aluminum mesh or a stainless steel mesh. In this invention, the thickness of the substrate is preferably 0.1 cm. This invention uses a mesh material as the substrate, reducing the production cost of the electrode material, improving economic efficiency, and simultaneously increasing the specific surface area of ​​the substrate.

[0032] The electrode material provided by the present invention includes an α-PbO2 layer, wherein the thickness of the α-PbO2 layer is preferably 10-13 μm, more preferably 11.9-12.3 μm.

[0033] The electrode material provided by this invention includes an active layer, which is β-PbO2 and nano-thulium oxide and cocamidopropylamine oxide doped in the β-PbO2. In this invention, the average particle size of the nano-thulium oxide is preferably 24-25 nm, more preferably 24.3-24.9 nm. In this invention, the total mass percentage of nano-thulium oxide and cocamidopropylamine oxide in the active layer is preferably 2.8-6.9%, more preferably 4-6.3%; the mass ratio of nano-thulium oxide to cocamidopropylamine oxide is preferably 1:1-2, more preferably 1:1.5-2. In this invention, the thickness of the active layer is preferably 20-25 μm, more preferably 21-24.5 μm, and even more preferably 23.1-24.5 μm.

[0034] The electrode material provided by this invention is uniform and dense, with low impedance, high electron transfer rate and conductivity, which is beneficial to improving the removal efficiency of chloride ions, COD and ammonia nitrogen, and can reduce the energy consumption of electrocatalytic oxidation treatment of wastewater.

[0035] The present invention also provides a method for preparing the electrode material described in the above technical solution, comprising the following steps:

[0036] A first electrodeposition is performed on the substrate surface to obtain an α-PbO2 layer; the electroplating solution used for the first electrodeposition is an alkaline solution of lead oxide;

[0037] A second electrodeposition is performed on the surface of the α-PbO2 layer to obtain the electrode material; the electroplating solution for the second electrodeposition is a mixed solution of lead nitrate, nano-thulium oxide, cocamidopropylamine oxide, nitric acid and sodium fluoride.

[0038] This invention involves a first electrodeposition on a substrate surface to obtain an α-PbO2 layer. Preferably, before the first electrodeposition, the process includes immersing the substrate material in an acidic solution for etching. Preferably, before etching, the process also includes cutting the substrate material and then sequentially performing sandblasting and washing. The dimensions of the cut substrate material are preferably 5cm × 1cm × 0.1cm (length × width × thickness). Sandblasting is preferably performed using 180-mesh white corundum. Sandblasting removes oxides and impurities from the substrate material surface. The washing process preferably includes sequential acetone washing and water washing. The acetone washing is preferably performed under ultrasonic conditions, with the ultrasonic time preferably being 20–60 min, more preferably 30–50 min. The water washing is preferably performed under ultrasonic conditions in deionized water, with the ultrasonic time preferably being 18–22 min, more preferably 20 min.

[0039] In this invention, the acidic solution preferably includes hydrofluoric acid or methanesulfonic acid, more preferably hydrofluoric acid; the mass concentration of the acidic solution is preferably 8-12%, more preferably 10%. This invention does not have special requirements on the amount of acidic solution used, as long as it is sufficient to immerse the matrix material.

[0040] In this invention, the immersion temperature is preferably 85–95°C, more preferably 90°C; the immersion time is preferably 10–30 min, more preferably 15–25 min. This invention preferably utilizes a water bath to provide the required immersion temperature. This invention increases the specific surface area of ​​the substrate by etching the surface of the substrate material to form a uniformly textured, uneven surface.

[0041] In this invention, the etching process preferably further includes: sequentially washing the etched product with anhydrous ethanol and deionized water, wherein the anhydrous ethanol washing is preferably performed 2 to 4 times, more preferably 3 times; and the deionized water washing is preferably performed 2 to 4 times, more preferably 3 times. Preferably, the substrate is stored in anhydrous ethanol.

[0042] In this invention, the first electrodeposition electroplating solution is an alkaline solution of lead oxide; the alkaline solution of lead oxide includes lead oxide and an alkaline substance, wherein the alkaline substance is preferably sodium hydroxide or potassium hydroxide; the molar concentration of lead oxide is preferably 0.1-0.5 mol / L, more preferably 0.3-0.4 mol / L; the molar concentration of the alkaline substance is preferably 3-4 mol / L, more preferably 3.5-3.8 mol / L.

[0043] In this invention, the temperature of the first electrodeposition is preferably 15–50°C, more preferably 30–35°C; the current density of the first electrodeposition is preferably 10–30 mA / cm². 2 More preferably 15–25 mA / cm 2 The preferred electrodeposition time is 30–60 min, more preferably 40–45 min. In this invention, the first electrodeposition is preferably accompanied by stirring, and the stirring speed is preferably 200–400 rpm, more preferably 200–300 rpm. In this invention, the anode for the first electrodeposition is preferably a substrate, and the cathode for the first electrodeposition is preferably a stainless steel plate; the areas of the anode and cathode are preferably the same; the distance between the anode and cathode is preferably 1–3 cm, more preferably 1.5–2.5 cm.

[0044] In this invention, the process after the first electrodeposition preferably further includes: sequentially washing the product after the first electrodeposition with anhydrous ethanol and then with deionized water. In this invention, the number of times the anhydrous ethanol is washed is preferably 2 to 4 times, more preferably 3 times; the number of times the deionized water is washed is preferably 2 to 4 times, more preferably 3 times.

[0045] After obtaining the α-PbO2 layer, the present invention performs a second electrodeposition on the surface of the α-PbO2 layer to obtain the electrode material. In the present invention, the electroplating solution for the second electrodeposition is preferably a mixed solution of lead nitrate, nano-thulium oxide, cocamidopropylamine oxide, nitric acid, and sodium fluoride. Preferably, the present invention dissolves lead nitrate, nano-thulium oxide, cocamidopropylamine oxide, nitric acid, and sodium fluoride in deionized water to obtain the electroplating solution for the second electrodeposition. In this invention, the molar concentration of lead nitrate in the second electrodeposition electroplating solution is preferably 0.1–0.5 mol / L, more preferably 0.2–0.3 mol / L; the molar concentration of nitric acid in the second electrodeposition electroplating solution is preferably 0.08–0.12 mol / L, more preferably 0.1 mol / L; the molar concentration of sodium fluoride in the second electrodeposition electroplating solution is preferably 1–4 mmol / L, more preferably 2–3 mmol / L; the molar concentration of cocamidopropylamine oxide in the second electrodeposition electroplating solution is preferably 1–4 mmol / L, more preferably 2–3 mmol / L; and the mass concentration of nano-thulium oxide in the second electrodeposition electroplating solution is preferably 0.5–3 g / L, more preferably 1.7–2.8 g / L.

[0046] In this invention, the temperature of the second electrodeposition is preferably 58–62°C, more preferably 60°C; the current density of the second electrodeposition is preferably 30–60 mA / cm². 2 More preferably 35–40 mA / cm 2 The second electrodeposition time is preferably 60–120 min, more preferably 90–110 min. In this invention, the second electrodeposition is preferably accompanied by stirring, and the stirring speed is preferably 200–400 rpm, more preferably 200–300 rpm. In this invention, the anode for the second electrodeposition is preferably the product after the first electrodeposition, and the cathode for the second electrodeposition is preferably a stainless steel plate; the areas of the anode and cathode are preferably the same; the distance between the anode and cathode is preferably 1–3 cm, more preferably 2–2.5 cm.

[0047] In this invention, the process after the second electrodeposition preferably further includes: sequentially washing the product with anhydrous ethanol and then with deionized water. In this invention, the number of times the anhydrous ethanol is washed is preferably 2 to 4 times, more preferably 3 times; the number of times the deionized water is washed is preferably 2 to 4 times, more preferably 3 times.

[0048] This invention also provides the application of the electrode material described in the above-described technical solutions or the electrode material prepared by the preparation method described in the above-described technical solutions as an anode material for electrocatalytic oxidation. In this invention, the electrocatalytic oxidation is preferably electrocatalytic oxidation for wastewater treatment.

[0049] To further illustrate the present invention, the technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0050] Example 1

[0051] Aluminum mesh was cut into 5cm×1cm×0.1cm sizes. After sandblasting with 180-mesh white corundum, the mesh was ultrasonically washed in acetone for 20 minutes and then ultrasonically washed in deionized water for 20 minutes to obtain a pretreated aluminum mesh. The pretreated aluminum mesh was then immersed in a 10% hydrofluoric acid solution at 90℃ (water bath) for 10 minutes for etching. After cleaning three times with anhydrous ethanol and three times with deionized water, the aluminum mesh substrate was obtained.

[0052] Yellow lead oxide and potassium hydroxide were dissolved in deionized water to obtain an alkaline lead oxide solution with a molar concentration of 0.1 mol / L for lead oxide and 3.5 mol / L for potassium hydroxide. An aluminum mesh substrate was used as the anode, and a stainless steel plate of the same area was used as the cathode (the distance between the anode and cathode plates was 1 cm). After the first electrodeposition using the alkaline lead oxide solution as the electroplating bath, the plating solution was first rinsed three times with anhydrous ethanol and then three times with deionized water to obtain an α-PbO2 layer. The first electrodeposition temperature was 15℃, and the current density was 10 mA / cm². 2 The time was 30 minutes, and the first electrodeposition was accompanied by stirring at 200 rpm;

[0053] Lead nitrate, nitric acid, sodium fluoride, thulium oxide nanoparticles with an average particle size of 24.1 nm, and cocamidopropylamine oxide were dissolved in deionized water to obtain a mixed solution. The concentrations of the components in the mixed solution were: 0.1 mol / L lead nitrate, 0.1 mol / L nitric acid, 1 mmol / L sodium fluoride, 0.5 g / L thulium oxide nanoparticles, and 1 mmol / L cocamidopropylamine oxide. Using the product after the first electrodeposition as the anode and a stainless steel plate of the same area as the cathode (the distance between the anode and cathode plates was 1 cm), a second electrodeposition was performed using the mixed solution as the electroplating bath. The electrode material was obtained by first cleaning it three times with anhydrous ethanol and then three times with deionized water. The temperature of the second electrodeposition was 60 °C and the current density was 30 A / cm. 2 The time was 60 minutes, and the second electrodeposition was accompanied by stirring at a speed of 200 rpm.

[0054] Example 2

[0055] Titanium mesh was cut into 5cm×1cm×0.1cm pieces, polished with 180-mesh white corundum, ultrasonically washed in acetone for 20 minutes, and then ultrasonically washed in deionized water for 20 minutes to obtain pretreated titanium mesh. The pretreated titanium mesh was then immersed in a 10% methanesulfonic acid solution at 90℃ (water bath) for 30 minutes for etching. After cleaning with anhydrous ethanol three times and then with deionized water twice, the titanium mesh substrate was obtained.

[0056] Yellow lead oxide and sodium hydroxide were dissolved in deionized water to obtain an alkaline lead oxide solution with a molar concentration of 0.5 mol / L for lead oxide and 3.5 mol / L for sodium hydroxide. A titanium mesh substrate was used as the anode, and a stainless steel plate of the same area was used as the cathode (the distance between the anode and cathode plates was 3 cm). After the first electrodeposition using the alkaline lead oxide solution, the plate was first cleaned twice with anhydrous ethanol and then three times with deionized water to obtain an α-PbO2 layer. The first electrodeposition temperature was 50℃, and the current density was 30 mA / cm². 2 The time was 60 minutes, and the first electrodeposition was accompanied by stirring at 400 rpm.

[0057] Lead nitrate, nitric acid, sodium fluoride, thulium oxide nanoparticles with an average particle size of 24.3 nm, and cocamidopropylamine oxide were dissolved in deionized water to obtain a mixed solution. The concentrations of the components in the mixed solution were: 0.5 mol / L lead nitrate, 0.1 mol / L nitric acid, 4 mmol / L sodium fluoride, 3 g / L thulium oxide nanoparticles, and 4 mmol / L cocamidopropylamine oxide. Using the product after the first electrodeposition as the anode and a stainless steel plate of the same area as the cathode (the distance between the anode and cathode plates was 3 cm), a second electrodeposition was performed using the mixed solution as the electroplating bath. The electrode material was obtained by first cleaning it three times with anhydrous ethanol and then twice with deionized water. The temperature of the second electrodeposition was 60 °C and the current density was 60 A / cm². 2 The time was 120 min, and the second electrodeposition was accompanied by stirring at a speed of 400 rpm.

[0058] Example 3

[0059] Stainless steel mesh was cut into 5cm×1cm×0.1cm sizes. After sandblasting with 180-mesh white corundum, the stainless steel mesh was ultrasonically washed in acetone for 20 minutes and then ultrasonically washed in deionized water for 20 minutes to obtain pretreated stainless steel mesh. The pretreated stainless steel mesh was then immersed in a 10% hydrofluoric acid solution at 90℃ (water bath) for 15 minutes for etching. After cleaning twice with anhydrous ethanol and twice with deionized water, the stainless steel mesh substrate was obtained.

[0060] Yellow lead oxide and potassium hydroxide were dissolved in deionized water to obtain an alkaline lead oxide solution with a molar concentration of 0.3 mol / L for lead oxide and 3.5 mol / L for potassium hydroxide. A stainless steel mesh substrate was used as the anode, and a stainless steel plate of the same area was used as the cathode (the distance between the anode and cathode plates was 1.5 cm). After the first electrodeposition using the alkaline lead oxide solution, the plate was first cleaned twice with anhydrous ethanol and then three times with deionized water to obtain an α-PbO2 layer. The first electrodeposition temperature was 30℃, and the current density was 15 mA / cm². 2 The time was 45 minutes, and the first electrodeposition was accompanied by stirring at 300 rpm.

[0061] Lead nitrate, nitric acid, sodium fluoride, thulium oxide nanoparticles with an average particle size of 24.2 nm, and cocamidopropylamine oxide were dissolved in deionized water to obtain a mixed solution. The concentrations of the components in the mixed solution were: 0.3 mol / L lead nitrate, 0.1 mol / L nitric acid, 2 mmol / L sodium fluoride, 1.7 g / L thulium oxide nanoparticles, and 2 mmol / L cocamidopropylamine oxide. Using the product after the first electrodeposition as the anode and a stainless steel plate of the same area as the cathode (the distance between the anode and cathode plates was 2.5 cm), a second electrodeposition was performed using the mixed solution as the electroplating bath. The electrode material was first cleaned three times with anhydrous ethanol and then three times with deionized water. The temperature of the second electrodeposition was 60 °C and the current density was 35 A / cm. 2 The time was 120 min, and the second electrodeposition was accompanied by stirring at a speed of 200 rpm.

[0062] Example 4

[0063] Aluminum mesh was cut into 5cm×1cm×0.1cm sizes. After sandblasting with 180-mesh white corundum, the mesh was ultrasonically washed in acetone for 20 minutes and then ultrasonically washed in deionized water for 20 minutes to obtain a pretreated aluminum mesh. The pretreated aluminum mesh was then immersed in a 10% methanesulfonic acid solution at 90℃ (water bath) for 25 minutes for etching. After cleaning three times with anhydrous ethanol and three times with deionized water, the aluminum mesh substrate was obtained.

[0064] Yellow lead oxide and potassium hydroxide were dissolved in deionized water to obtain an alkaline lead oxide solution with a molar concentration of 0.4 mol / L for lead oxide and 3.5 mol / L for potassium hydroxide. An aluminum mesh substrate was used as the anode, and a stainless steel plate of the same area was used as the cathode (the distance between the anode and cathode plates was 1 cm). After the first electrodeposition using the alkaline lead oxide solution, the plate was first cleaned three times with anhydrous ethanol and then twice with deionized water to obtain an α-PbO2 layer. The first electrodeposition temperature was 30℃, and the current density was 25 mA / cm². 2The time was 45 minutes, and the first electrodeposition was accompanied by stirring at a speed of 200 rpm;

[0065] Lead nitrate, nitric acid, sodium fluoride, thulium oxide nanoparticles with an average particle size of 24.9 nm, and cocamidopropylamine oxide were dissolved in deionized water to obtain a mixed solution. The concentrations of the components in the mixed solution were: 0.2 mol / L lead nitrate, 0.1 mol / L nitric acid, 3 mmol / L sodium fluoride, 2.5 g / L thulium oxide nanoparticles, and 3 mmol / L cocamidopropylamine oxide. Using the product after the first electrodeposition as the anode and a stainless steel plate of the same area as the cathode (the distance between the anode and cathode plates was 2.5 cm), a second electrodeposition was performed using the mixed solution as the electroplating bath. The electrode material was obtained by first cleaning it three times with anhydrous ethanol and then three times with deionized water. The temperature of the second electrodeposition was 60 °C and the current density was 40 A / cm. 2 The time was 60 minutes, and the second electrodeposition was accompanied by stirring at a speed of 200 rpm.

[0066] Example 5

[0067] Stainless steel mesh was cut into 5cm×1cm×0.1cm sizes. After sandblasting with 180-mesh white corundum, the stainless steel mesh was ultrasonically washed in acetone for 20 minutes and then ultrasonically washed in deionized water for 20 minutes to obtain pretreated stainless steel mesh. The pretreated stainless steel mesh was then immersed in a 10% hydrofluoric acid solution at 90℃ (water bath) for 30 minutes for etching. After cleaning twice with anhydrous ethanol and twice with deionized water, the stainless steel mesh substrate was obtained.

[0068] Yellow lead oxide and potassium hydroxide were dissolved in deionized water to obtain an alkaline lead oxide solution with a molar concentration of 0.1 mol / L for lead oxide and 3.5 mol / L for potassium hydroxide. A stainless steel mesh substrate was used as the anode, and a stainless steel plate of the same area was used as the cathode (the distance between the anode and cathode plates was 2 cm). After the first electrodeposition using the alkaline lead oxide solution as the electroplating bath, the plating solution was first rinsed twice with anhydrous ethanol and then twice with deionized water to obtain an α-PbO2 layer. The first electrodeposition temperature was 35℃, and the current density was 15 mA / cm². 2 The time was 60 minutes, and the first electrodeposition was accompanied by stirring at 300 rpm.

[0069] Lead nitrate, nitric acid, sodium fluoride, thulium oxide nanoparticles with an average particle size of 24.5 nm, and cocamidopropylamine oxide were dissolved in deionized water to obtain a mixed solution. The concentrations of the components in the mixed solution were: 0.5 mol / L lead nitrate, 0.1 mol / L nitric acid, 4 mmol / L sodium fluoride, 2.8 g / L thulium oxide nanoparticles, and 2.5 mmol / L cocamidopropylamine oxide. Using the product after the first electrodeposition as the anode and a stainless steel plate of the same area as the cathode (the distance between the anode and cathode plates was 2 cm), a second electrodeposition was performed using the mixed solution as the electroplating bath. The electrode material was first cleaned twice with anhydrous ethanol and then twice with deionized water. The temperature of the second electrodeposition was 60 °C and the current density was 35 A / cm. 2 The time was 90 minutes, and the second electrodeposition was accompanied by stirring at a speed of 300 rpm.

[0070] Comparative Example 1

[0071] The electrode material was prepared according to the method of Example 1, except that the electroplating solution used for the second electrodeposition did not contain nano-thulium oxide and cocamidopropylamine oxide.

[0072] Table 1 lists the characteristic parameters of the thickness of the α-PbO2 layer and the active layer, as well as the mass percentage of nano-thulium oxide and cocamidopropylamine oxide in the active layer of the electrode materials prepared in Examples 1-5 and Comparative Example 1.

[0073] Table 1. Characteristic parameters of the electrode materials prepared in Examples 1-5 and Comparative Example 1

[0074]

[0075] Figure 1 This is a physical image of the electrode material prepared in Comparative Example 1. Figure 2 This is a photograph of the electrode material prepared in Example 4. According to... Figure 1 and Figure 2 It can be seen that the electrode surface after being doped with nano-thulium oxide and cocamidopropylamine oxide in the active layer is regular and dense.

[0076] The electrode materials prepared in Example 4 and Comparative Example 1 were examined by scanning electron microscopy (SEM) to obtain SEM images, as shown below. Figures 3-4 As shown, where Figure 3 The image shows a SEM image of the electrode material prepared in Comparative Example 1. Figure 4 SEM image of the electrode material prepared in Example 4. (Comparison) Figure 3 and Figure 4It can be seen that after doping the active layer with nano-thulium oxide and cocamidopropylamine oxide, the crystal shape on the electrode surface changes from an irregular tetrahedron to a granular shape, and the grain size becomes smaller and more compact, thereby improving the density of the electrode material surface and enhancing the stability of the active layer.

[0077] Electrochemical tests were performed on the electrode materials prepared in Examples 1-5 and Comparative Example 1 using a CHI660E electrochemical workstation. The oxygen evolution potential, chlorine evolution potential, and charge transfer resistance (Rct value) of the electrodes were obtained through AC impedance spectroscopy and linear sweep spectroscopy. The results are listed in Table 2. The electrochemical tests were conducted in a three-electrode system. The oxygen evolution potential was measured in 0.5 mol / L sulfuric acid, and the chlorine evolution potential was measured in 0.5 mol / L sodium chloride. The treatment scale for desulfurization wastewater was 400 mL. Figure 5 This is a comparison graph of the oxygen evolution curves of Example 4 and Comparative Example 1. Figure 6 This is a comparison graph of the chlorine evolution curves of Example 4 and Comparative Example 1.

[0078] Using the electrode materials prepared in Examples 1-5 and Comparative Example 1 as the anode and stainless steel as the cathode, 400 mL of desulfurization wastewater was subjected to electrocatalytic oxidation treatment. The electrode spacing was 1.5 cm and the current density was 80 mA / cm². 2 The mixture was stirred at 200 rpm. The chloride ion concentration in the desulfurization wastewater was 8650 mg / L, the initial COD concentration was 375 mg / L, and the initial ammonia nitrogen concentration was 46.2 mg / L. After 2 hours of reaction, the removal rates of chloride ions, COD, and ammonia nitrogen were measured, and the results are listed in Table 2.

[0079] Table 2 Performance parameters of the electrode materials prepared in Examples 1-5 and Comparative Example 1

[0080]

[0081] Combine Table 2 and Figures 5-6 It can be seen that after doping the active layer with nano-thulium oxide and cocamidopropylamine oxide, the oxygen evolution potential of the electrode is increased, the chloride evolution potential is decreased, and the removal rates of chloride ions, COD and ammonia nitrogen are improved. Among them, Example 4 has the best effect.

[0082] The electrode material provided by this invention has the advantages of low preparation cost, dense surface morphology, strong conductivity, high oxygen evolution potential, and low chlorine evolution potential. When the electrode material provided by this invention is used as the anode for electrocatalytic oxidation treatment of desulfurization wastewater, it can improve the removal rate of chloride ions, COD, and ammonia nitrogen in the desulfurization wastewater.

[0083] Although the above embodiments have provided a detailed description of the present invention, they are only some embodiments of the present invention, and not all embodiments. People can obtain other embodiments based on these embodiments without creative effort, and these embodiments all fall within the protection scope of the present invention.

Claims

1. An electrode material comprising a matrix, an α-PbO2 layer, and an active layer sequentially stacked; The active layer is β-PbO2 and nano-thulium oxide and cocamidopropylamine oxide doped in the β-PbO2.

2. The electrode material according to claim 1, characterized in that, The thickness of the active layer is 20–25 μm; The total mass percentage of nano-thulium oxide and cocamidopropylamine oxide in the active layer is 2.8–6.9%. The mass ratio of the nano-thulium oxide to cocamidopropylamine oxide is 1:1 to 2.

3. The electrode material according to claim 1, characterized in that, The thickness of the α-PbO2 layer is 10–13 μm.

4. The electrode material according to claim 1, characterized in that, The substrate includes aluminum mesh, titanium mesh, or stainless steel mesh.

5. A method for preparing the electrode material according to any one of claims 1 to 4, comprising the following steps: A first electrodeposition is performed on the substrate surface to obtain an α-PbO2 layer; the electroplating solution used for the first electrodeposition is an alkaline solution of lead oxide; A second electrodeposition is performed on the surface of the α-PbO2 layer to obtain the electrode material; the electroplating solution for the second electrodeposition is a mixed solution of lead nitrate, nano-thulium oxide, cocamidopropylamine oxide, nitric acid and sodium fluoride.

6. The preparation method according to claim 5, characterized in that, The process before the first electrodeposition also includes: immersing the substrate material in an acidic solution for etching; The acidic solution includes hydrofluoric acid or methanesulfonic acid; the mass concentration of the acidic solution is 8-12%. The soaking temperature is 85-95℃, and the soaking time is 10-30 minutes.

7. The preparation method according to claim 5, characterized in that, The alkaline solution of lead oxide includes lead oxide and an alkaline substance, wherein the molar concentration of lead oxide is 0.1–0.5 mol / L and the molar concentration of the alkaline substance is 3–4 mol / L. The first electrodeposition temperature is 15–50°C, and the current density is 10–30 mA / cm². 2 The time is 30 to 60 minutes.

8. The preparation method according to claim 5, characterized in that, The second electrodeposition electroplating solution contains lead nitrate at a molar concentration of 0.1–0.5 mol / L, nitric acid at a molar concentration of 0.08–0.12 mol / L, sodium fluoride at a molar concentration of 1–4 mmol / L, cocamidopropylamine oxide at a molar concentration of 1–4 mol / L, and nano-thulium oxide at a mass concentration of 0.5–3 g / L.

9. The preparation method according to claim 5 or 8, characterized in that, The second electrodeposition temperature is 58–62°C, and the current density is 30–60 mA / cm². 2 The time is 60 to 120 minutes.

10. The application of the electrode material according to any one of claims 1 to 4 or the electrode material prepared by the preparation method according to any one of claims 5 to 9 as an anode material for electrocatalytic oxidation.

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