Foam titanium anode material with tin-antimony coating and preparation method of foam titanium anode material

Abstract

The invention belongs to the technical field of electrochemical materials, and discloses a foam titanium anode material with a tin-antimony coating and a preparation method thereof.The preparation method comprises the following steps that S1, Sn salt and Sb salt serve as raw materials to prepare a tin-antimony coating gel solution; and S2, coating the tin-antimony coating gel solution and fixing the tin-antimony coating gel solution on the surface of a foam titanium anode to obtain the foam titanium anode material with the tin-antimony coating. According to the preparation method, the modified material is prepared into the gel solution, the surface is modified in a coating mode, the pore structure of the foam titanium is not damaged, the advantages of the foam titanium material are fully played while surface modification is achieved, and the prepared foam titanium anode material with the tin-antimony coating is complete in structure and high in stability. And the characteristic of high porosity is reserved, and the anode area is larger.

Description

Technical Field

[0001] The invention belongs to the technical field of electrochemical materials, and particularly relates to a foamed titanium anode material with a tin-antimony coating and a preparation method thereof. Background Art

[0002] Among the many methods for treating complexed heavy metals, Fenton-based advanced oxidation technology has attracted much attention. Its principle is to first add an oxidant (Fenton's reagent, a combination of hydrogen peroxide and ferrous ions) to the wastewater to destroy the organic complexing agent, thereby dissociating the heavy metal ions into a free state. Conventional precipitation or adsorption methods are then used to remove the heavy metal ions from the wastewater. This method has the characteristics of high efficiency in treating complexed heavy metals, but the use of oxidants is limited by the safety of chemical transportation and storage. It is not suitable for many production enterprises with small wastewater production, and the water treatment efficiency is unstable.

[0003] To this end, in 1987, Gaze et al. proposed advanced oxidation processes (AOPs), which address the challenges of conventional oxidation methods. Compared to Fenton's advanced oxidation technology, electrochemical advanced oxidation (AOPs) requires no chemical reagents and does not cause secondary pollution. It also offers advantages such as easy operation and mild reaction conditions. Electrocatalytic oxidation, a form of advanced oxidation technology, has attracted widespread attention for its high efficiency, stable performance, and lack of selectivity. During the electrochemical treatment process, water molecules are oxidized at the anode surface to generate highly oxidizing reactive oxygen species, which in turn oxidize pollutants, thereby degrading and removing organic pollutants.

[0004] In this process, the selection and design of the anode material directly affects the purification efficiency. To this end, the Chinese invention patent with application number CN202210447720.7 discloses a titanium-based antimony-doped tin dioxide microporous electrode, which adopts the steps of electroplating antimony-doped tin dioxide, ultrasonic impregnation, high-temperature pyrolysis and surface modification on a foam titanium substrate to prepare an antimony-doped tin dioxide active layer on the foam titanium surface. The antimony-doped tin dioxide active layer and the titanium substrate are uniformly compounded in units of microparticles, taking into account the adhesion and mechanical strength of the electrode active layer, thereby improving the service life of the electrode under high voltage; however, the above method is cumbersome to operate, and the foam titanium material is different from other conventional electrodes. When the surface is modified with micropowder, it will inevitably damage the pores on the surface of the foam titanium, which will affect the mass transfer efficiency and reduce the treatment efficiency.

[0005] In view of this, the present invention is proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for preparing a foam titanium anode material with a tin-antimony coating in order to address the problems in the prior art. The modified material is made into a gel solution, and the surface is modified by coating. This will not destroy the pore structure of the foam titanium itself, and will fully utilize the advantages of the foam titanium material while achieving surface modification.

[0007] Another object of the present invention is to provide a foamed titanium anode material with a tin-antimony coating, which, while modifying the surface, does not damage or affect the void structure, so that the anode material maintains a high porosity, thereby having a larger anode area and improving the processing efficiency.

[0008] In order to achieve the above object, the first aspect of the present invention provides a method for preparing a foamed titanium anode material having a tin-antimony coating, comprising the following steps:

[0009] S1. Prepare a tin-antimony coating gel solution using Sn salt and Sb salt as raw materials;

[0010] S2. Coating and fixing the tin-antimony coating gel solution on the surface of the titanium foam anode to obtain a titanium foam anode material with a tin-antimony coating.

[0011] In the above scheme, the tin-antimony coating used for surface modification is first prepared to form a gel solution, and then modified on the surface of the titanium foam anode by coating. Compared with the existing micropowder modification method, the degree of damage to the pore structure of the titanium foam surface is reduced, and the coating has better uniformity and consistency. The obtained titanium foam anode material with tin-antimony coating has higher treatment efficiency and better water treatment capacity.

[0012] Furthermore, in the above preparation method, step S1 is specifically as follows:

[0013] A catalyst is added to a mixed solution of Sn salt and Sb salt to react, and then mixed with citric acid and n-butanol, and aged to obtain a tin-antimony coating gel;

[0014] Preferably, the Sn salt is selected from a chloride or sulfate of Sn, the Sb salt is selected from a chloride or sulfate of Sb, and the acid radical ions of the Sn salt and the Sb salt are the same;

[0015] More preferably, the Sn salt is SnCl4·5H2O; the Sb salt is SbCl3;

[0016] Preferably, the solvent of the mixed solution is selected from anhydrous ethanol, acetone, and water;

[0017] More preferably, the solvent of the mixed solution is anhydrous ethanol;

[0018] Preferably, the catalyst is the acid corresponding to the acid ions on the Sn salt and the Sb salt.

[0019] Furthermore, the molar ratio of Sn salt to Sb salt in the mixed solution is (9-19):1.

[0020] The ratio of Sn salt to Sb salt in the above scheme is a relatively excellent ratio range discovered by technicians based on extensive research. A ratio that is too high or too low will directly affect the performance of the obtained anode material.

[0021] There is currently no definite conclusion on the cause of the above phenomenon. It is speculated that it may be because: when the proportion of Sn salt is too high, the conductivity and electrode activity of the electrode may be insufficient to provide sufficient catalytic ability, thereby reducing the catalytic effect of the electrode; conversely, if the proportion of Sn salt is too low, the electrochemical impedance of the system will be too high, which is not conducive to the occurrence of catalytic oxidation reactions and leads to a decrease in the stability of the coating.

[0022] Furthermore, in step S1, citric acid, n-butanol, and a solvent are mixed to obtain an ester substance solution, and the mixture is performed in the form of an ester substance solution;

[0023] Preferably, the solvent of the ester substance solution is selected from anhydrous ethanol, acetone, and water;

[0024] More preferably, the solvent of the ester substance solution is anhydrous ethanol;

[0025] Preferably, the preparation temperature of the ester substance solution is 35°C-70°C.

[0026] Furthermore, step S2 is: coating the tin-antimony coating gel solution on the surface of the titanium foam anode and drying it, and then thermally oxidizing it at a preset temperature, and repeating it 10-20 times to obtain a titanium foam anode material with a tin-antimony coating.

[0027] Preferably, the number of repetitions is 12-17 times.

[0028] More preferably, the number of repetitions is 15 times.

[0029] In the above scheme, the brushing method can better ensure the uniformity of the surface modification layer. However, considering that the brushing method cannot guarantee that all the gaps are filled in one time, nor can it guarantee sufficient contact between the electrode and the gel solution, it is necessary to repeat the brushing many times. If the number of brushing times is less than 10 times, it may not be possible to ensure that the tin-antimony coating fully covers the surface of the foam titanium anode, resulting in reduced electrode performance; if the number of brushing times is too many, exceeding 20 times, it may cause the titanium nanotubes (TiO2-NTs) on the surface of the foam titanium to be damaged or fall off, affecting the service life of the foam titanium anode.

[0030] As a specific embodiment, by controlling the concentration of Sn salt in the mixed solution of Sn salt and Sb salt, the above-mentioned tin-antimony coating gel solution coating, drying, and thermal oxidation operations are repeated 10-20 times, so that the weight gain of the final titanium foam anode material is controlled to be 20.79-27.72 mg / cm compared with the initial weight of the titanium foam anode. 3 .

[0031] The conventional method of performing a long thermal oxidation after a single immersion cannot effectively treat the surface with micropores. Bubbles may exist in the pores, resulting in a loose bond between the coating and the electrode, which in turn causes the coating to peel and fall off. The above-mentioned solution performs a short thermal oxidation after each coating, which can fix the coating while coating, and the short-term thermal oxidation increases the surface temperature of the foam titanium anode, which can better promote the discharge of bubbles in the micropores. The solution of the present invention effectively avoids this problem through multiple brushing, overcoming the technical defect that a single immersion cannot effectively perform surface modification on materials with micropores.

[0032] Furthermore, the preset temperature of thermal oxidation is 250°C-450°C.

[0033] Preferably, the thermal oxidation temperature in the preset temperature is 450°C.

[0034] Preferably, the duration of each thermal oxidation is 10 minutes.

[0035] Furthermore, the last thermal oxidation temperature is 450°C and the thermal oxidation time is 1 hour; the last long firing time is relatively longer in order to better improve the coating stability.

[0036] Furthermore, the titanium foam anode in step S2 is a titanium foam / TiO2-NTs composite material, which is obtained by using titanium foam as a raw material, forming TiO2-NTs on the surface by an anodic oxidation method, and then sintering.

[0037] Preferably, the cathode of the anodic oxidation method is selected from one of graphite, platinum, copper, iron and titanium.

[0038] Preferably, the electrolyte of the anodization method is an ethylene glycol solution of NH4F and H2O.

[0039] More preferably, the electrolyte is a solution of 0.5% wt NH4F and 2% vol H2O in ethylene glycol.

[0040] Preferably, the anodization voltage is 10V-100V.

[0041] Among the above preferred solutions, 50V is a relatively good choice. When the pressure is relatively low, particles are easily formed, while when the pressure is too high, the nanotube structure will be destroyed.

[0042] More preferably, the anodization voltage is 50V.

[0043] Preferably, the temperature of the electrolyte during the anodization process is 20°C.

[0044] Preferably, the anodizing time is 1 h to 3 h.

[0045] Preferably, the foamed titanium raw material is subjected to anodizing after surface polishing.

[0046] Furthermore, the firing process of step S2 is to gradually increase the temperature to 400° C.-500° C. at a preset heating rate.

[0047] Preferably, the preset heating rate is 2°C / min.

[0048] Preferably, the firing temperature is 450°C.

[0049] Preferably, the firing time is 1 hour to 3 hours.

[0050] Excessively high temperatures will cause the foam titanium anode plate to slag and the coating to peel off. The stability at low temperatures is poor. In actual production, it is more reasonable to set the temperature to 450°C.

[0051] Furthermore, in step S2, the surface treatment is specifically to polish the titanium foam with a polishing liquid, wash with water, dry, and then prepare the titanium foam / TiO2-NTs composite material by an anodic oxidation method.

[0052] The titanium foam / TiO2-NTs composite material is dried, fired and cooled to obtain a titanium foam anode with surface treatment.

[0053] Preferably, the polishing liquid is a mixture of HF:HNO3:H2O in a molar ratio of 1:1:2.

[0054] The present invention also provides a foamed titanium anode material with a tin-antimony coating prepared by the above preparation method, as follows.

[0055] The surface of the prepared foam titanium anode material with tin-antimony coating presents a porous structure, and the raw material foam titanium used has a pore diameter ranging from 160 μm to 240 μm.

[0056] Preferably, the air permeability of the raw material titanium foam used is less than 3000m 3 / h·m 2 ·kpa.

[0057] Preferably, the porosity of the raw material titanium foam used is 30%-40%.

[0058] The beneficial effects of the present invention are:

[0059] 1. In the method of the present invention, the surface is modified by coating, which does not destroy the pore structure of the titanium foam itself. While achieving surface modification, the advantages of the titanium foam material are fully utilized; the titanium foam anode material with a tin-antimony coating prepared thereby has a complete structure, retains the characteristics of high porosity, and has a larger anode area.

[0060] 2. The present invention uses electro-oxidation to construct a titanium nanotube structure, increasing the effective electrode area and coating loading area. The formation of the nanotube structure also effectively enhances the catalytic activity of the anode. DETAILED DESCRIPTION

[0061] Exemplary embodiments of the present invention will be described in more detail below. Those skilled in the art will appreciate that the following embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0062] The present invention provides a method for preparing a foamed titanium anode material having a tin-antimony coating, which is characterized by comprising the following steps:

[0063] S1. Prepare a tin-antimony coating gel solution using Sn salt and Sb salt as raw materials;

[0064] S2. Coating and fixing the tin-antimony coating gel solution on the surface of the titanium foam anode to obtain a titanium foam anode material with a tin-antimony coating.

[0065] The above method reduces the probability of damage to the surface of the titanium foam during the modification process, and the anode material obtained thereby retains a high porosity.

[0066] The present invention is further described in detail below with reference to specific embodiments.

[0067] Example 1

[0068] As an embodiment of the present invention, this embodiment provides a method for preparing a foamed titanium anode material having a tin-antimony coating, which is specifically as follows.

[0069] According to actual needs, titanium foam (99.5% purity, 2 mm thickness) was cut into a circle with a diameter of 80 mm.

[0070] S1. Dissolve citric acid and n-butanol (15 mL) in a molar ratio of 1:5 in 5 mL of anhydrous ethanol, stir evenly in a constant temperature water bath at 60°C to obtain a mixed solution a.

[0071] 0.3506gSnCl4·5H2O and 0.02509gSbCl3 (the molar ratio of SnCl4·5H2O to SbCl3 is 9:1) were dissolved in 10mL of anhydrous ethanol to obtain a mixed solution c, in which Sn 4+The concentration of HCl was 0.1 mol / L, 5 mL of 1 mol / L HCl was added as a hydrolysis and polycondensation catalyst, and ultrasonication was performed for 30 min until the solution was ultrasonically uniform to obtain a mixed solution b.

[0072] The mixed solution a and the mixed solution b were mixed evenly, and ultrasonicated in an ultrasonic instrument until the solution was clear. The clear solution was aged for 2 hours to obtain a tin-antimony coating gel.

[0073] S2. Use HF, HNO3 and H2O as raw materials and prepare a mixed polishing liquid with a molar ratio of 1:1:2. Polish the cut foam titanium, pickle it for 8 minutes, rinse it with deionized water, and place it in the air to dry naturally.

[0074] Anodic oxidation was performed using polished and dried titanium foam as the anode and graphite as the cathode at a constant voltage of 50V. The electrolyte temperature was maintained at 20°C by an external cooling pump. The electrolyte composition was a 0.5% wt NH₄F and 2% vol HO solution in ethylene glycol. The oxidation time was 2 hours.

[0075] The titanium foam / TiO2-NTs were air-dried. The prepared titanium foam-based TiO2-NTs were then fired in a muffle furnace at a heating rate of 2°C / min to 450°C, then held at that temperature for 2 hours and then naturally cooled to room temperature.

[0076] The tin-antimony coating gel prepared in step S1 was evenly coated on the surface of the titanium foam, placed in a blast drying oven, and dried at a temperature of 110°C for 20 minutes. It was then placed in a muffle furnace at a temperature of 450°C for thermal oxidation for a duration of 10 minutes. The above process was repeated 15 times, wherein the last heating was at a temperature of 450°C for 1 hour, to obtain a titanium foam anode material with a tin-antimony coating.

[0077] Example 2

[0078] As an embodiment of the present invention, this embodiment provides a method for preparing a foamed titanium anode material having a tin-antimony coating, which is specifically as follows.

[0079] According to actual needs, titanium foam (99.5% purity, 2 mm thickness) was cut into a circle with a diameter of 80 mm.

[0080] S1. Dissolve citric acid and n-butanol (15 mL) in a molar ratio of 1:5 in 5 mL of anhydrous ethanol, stir evenly in a constant temperature water bath at 60°C to obtain a mixed solution a.

[0081] 3.159 g of SnCl4·5H2O and 0.108 g of SbCl3 were dissolved in 30 mL of anhydrous ethanol to obtain a mixed solution c. 5 mL of 1 mol / L HCl was added as a hydrolysis and polycondensation catalyst, and ultrasonication was performed for 30 min until the solution was homogeneous to obtain a mixed solution b.

[0082] The mixed solution a and the mixed solution b were mixed evenly, and ultrasonicated in an ultrasonic instrument until the solution was clear. The clear solution was aged for 2 hours to obtain a tin-antimony coating gel.

[0083] S2. Use HF, HNO3 and H2O as raw materials and prepare a mixed polishing liquid with a molar ratio of 1:1:2. Polish and pickle the cut foam titanium for 8 minutes, then rinse it with deionized water and place it in the air to dry naturally.

[0084] Anodic oxidation was performed using polished and dried titanium foam as the anode and graphite as the cathode at a constant voltage of 50V. The electrolyte temperature was maintained at 20°C by an external cooling pump. The electrolyte composition was a 0.5% wt NH₄F and 2% vol HO solution in ethylene glycol. The oxidation time was 2 hours.

[0085] The titanium foam / TiO2-NTs were air-dried. The prepared titanium foam-based TiO2-NTs were then fired in a muffle furnace at a heating rate of 2°C / min to 450°C, then held at that temperature for 2 hours and then naturally cooled to room temperature.

[0086] The tin-antimony coating gel prepared in step S1 was evenly coated on the surface of the titanium foam, placed in a blast drying oven, and dried at a temperature of 110°C for 20 minutes. It was then placed in a muffle furnace at a temperature of 450°C for thermal oxidation for a duration of 10 minutes. The above process was repeated 15 times, wherein the last heating was at a temperature of 450°C for 1 hour, to obtain a titanium foam anode material with a tin-antimony coating.

[0087] Using the preparation method described in Example 2, only the concentration of the precursor solution was changed to obtain other examples, as follows:

[0088]

[0089] Example 8

[0090] As an embodiment of the present invention, this embodiment provides a method for preparing a foamed titanium anode material having a tin-antimony coating, which is specifically as follows.

[0091] According to actual needs, titanium foam (99.5% purity, 2 mm thickness) was cut into a circle with a diameter of 80 mm.

[0092] S1. Dissolve citric acid and n-butanol (15 mL) in a molar ratio of 1:5 in 5 mL of anhydrous ethanol, stir evenly in a constant temperature water bath at 60°C to obtain a mixed solution a.

[0093] 3.159 g SnCl4·5H2O and 0.108 g SbCl3 (the molar ratio of SnCl4·5H2O to SbCl3 is 19:1) were dissolved in 30 mL of anhydrous ethanol to obtain a mixed solution c, in which Sn 4+ The concentration of HCl was 0.3 mol / L, 5 mL of 1 mol / L HCl was added as a hydrolysis and polycondensation catalyst, and ultrasonication was performed for 30 min until the solution was ultrasonically uniform to obtain a mixed solution b.

[0094] The mixed solution a and the mixed solution b were mixed evenly, and ultrasonicated in an ultrasonic instrument until the solution was clear. The clear solution was aged for 2 hours to obtain a tin-antimony coating gel.

[0095] S2. Use HF, HNO3 and H2O as raw materials and prepare a mixed polishing liquid with a molar ratio of 1:1:2. Polish and pickle the cut foam titanium for 8 minutes, then rinse it with deionized water and place it in the air to dry naturally.

[0096] Anodic oxidation was performed using polished and dried titanium foam as the anode and graphite as the cathode at a constant voltage of 50V. The electrolyte temperature was maintained at 20°C by an external cooling pump. The electrolyte composition was a 0.5% wt NH₄F and 2% vol HO solution in ethylene glycol. The oxidation time was 2 hours.

[0097] The titanium foam / TiO2-NTs were air-dried. The prepared titanium foam-based TiO2-NTs were then fired in a muffle furnace at a heating rate of 2°C / min to 450°C, then held at that temperature for 2 hours and then naturally cooled to room temperature.

[0098] The tin-antimony coating gel prepared in step S1 was evenly coated on the surface of the titanium foam, placed in a blast drying oven, and dried at a temperature of 110°C for 20 minutes. It was then placed in a muffle furnace at a temperature of 450°C for thermal oxidation for a duration of 10 minutes. The above process was repeated 15 times, wherein the last heating was at a temperature of 450°C for 2 hours to obtain a titanium foam anode material with a tin-antimony coating.

[0099] By adopting the preparation method described in Example 8, only the duration of the last thermal oxidation after the surface of the titanium foam is coated with the tin-antimony coating gel solution is changed to obtain other examples, as follows:

[0100]

[0101] Example 11

[0102] As an embodiment of the present invention, this embodiment provides a method for preparing a foamed titanium anode material having a tin-antimony coating, which is specifically as follows.

[0103] According to actual needs, titanium foam (99.5% purity, 2 mm thickness) was cut into a circle with a diameter of 80 mm.

[0104] S1. Dissolve citric acid and n-butanol (15 mL) in a molar ratio of 1:5 in 5 mL of anhydrous ethanol, stir evenly in a constant temperature water bath at 60°C to obtain a mixed solution a.

[0105] 1.053 g SnCl4·5H2O and 0.036 g SbCl3 (the molar ratio of SnCl4·5H2O to SbCl3 is 19:1) were dissolved in 30 mL of anhydrous ethanol to obtain a mixed solution c, in which Sn 4+ The concentration of HCl was 0.1 mol / L, 5 mL of 1 mol / L HCl was added as a hydrolysis and polycondensation catalyst, and ultrasonication was performed for 30 min until the solution was ultrasonically uniform to obtain a mixed solution b.

[0106] The mixed solution a and the mixed solution b were mixed evenly, and ultrasonicated in an ultrasonic instrument until the solution was clear. The clear solution was aged for 2 hours to obtain a tin-antimony coating gel.

[0107] S2. Use HF, HNO3 and H2O as raw materials and prepare a mixed polishing liquid with a molar ratio of 1:1:2. Polish and pickle the cut foam titanium for 8 minutes, then rinse it with deionized water and place it in the air to dry naturally.

[0108] Anodic oxidation was performed using polished and dried titanium foam as the anode and graphite as the cathode at a constant voltage of 50V. The electrolyte temperature was maintained at 20°C by an external cooling pump. The electrolyte composition was a 0.5% wt NH₄F and 2% vol HO solution in ethylene glycol. The oxidation time was 2 hours.

[0109] The titanium foam / TiO2-NTs were air-dried. The prepared titanium foam-based TiO2-NTs were then fired in a muffle furnace at a heating rate of 2°C / min to 450°C, then held at that temperature for 2 hours and then naturally cooled to room temperature.

[0110] The tin-antimony coating gel prepared in step S1 was evenly coated on the surface of the titanium foam, placed in a blast drying oven, and dried at a temperature of 110°C for 20 minutes. It was then placed in a muffle furnace at a temperature of 250°C for thermal oxidation for a duration of 10 minutes. The above process was repeated 15 times, wherein the last heating was at a temperature of 250°C for 1 hour, to obtain a titanium foam anode material with a tin-antimony coating.

[0111] By adopting the preparation method described in Example 11, only the temperature of the last thermal oxidation after the tin-antimony coating gel solution is applied to the titanium foam surface is changed (the temperature of multiple thermal oxidations before the last thermal oxidation is kept unchanged at 250° C.), other examples are obtained, as follows:

[0112]

[0113] On the basis of Example 13, only the number of coating layers of the tin-antimony coating gel solution on the surface of the titanium foam is changed to obtain other examples, as follows:

[0114]

[0115] Comparative Example 1

[0116] This comparative example adopts the same preparation method as that of Example 5, except that, in step S1, the ratio of Sn salt and Sb salt as raw materials and the concentration of the raw material solution are different. Specifically, step S1 in this comparative example is:

[0117] S1. Dissolve citric acid and n-butanol (15 mL) in a molar ratio of 1:5 in 5 mL of anhydrous ethanol, stir evenly in a constant temperature water bath at 60°C to obtain a mixed solution a.

[0118] 0.5265g SnCl4·5H2O and 0.038g SbCl3 (the molar ratio of SnCl4·5H2O to SbCl3 is 9:1) were dissolved in 30mL of anhydrous ethanol to obtain a mixed solution c, in which Sn 4+ The concentration of HCl was 0.05 mol / L, 5 mL of 1 mol / L HCl was added as a hydrolysis and polycondensation catalyst, and ultrasonication was performed for 30 min until the solution was ultrasonically uniform to obtain a mixed solution b.

[0119] The mixed solution a and the mixed solution b were mixed evenly, and ultrasonicated in an ultrasonic instrument until the solution was clear. The clear solution was aged for 2 hours to obtain a tin-antimony coating gel.

[0120] Comparative Example 2

[0121] This comparative example adopts the same preparation method as that of Example 8, except that, in step S2, the last thermal oxidation time of coating the foam titanium surface with the tin-antimony coating gel solution is different. Specifically, the coating process of the tin-antimony coating gel solution in step S2 in this comparative example is as follows:

[0122] The tin-antimony coating gel prepared in step S1 was evenly coated on the surface of the titanium foam, placed in a blast drying oven, and dried at a temperature of 110°C for 20 minutes. It was then placed in a muffle furnace at a temperature of 450°C for thermal oxidation for a duration of 10 minutes. The above process was repeated 15 times, wherein the last heating was at a temperature of 450°C for 0.5 hours to obtain a titanium foam anode material with a tin-antimony coating.

[0123] Comparative Example 3

[0124] This comparative example adopts the same preparation method as Example 11, except that, in step S2, the temperature of the last thermal oxidation of the tin-antimony coating gel solution applied to the surface of the titanium foam is different. Specifically, the coating process of the tin-antimony coating gel solution in step S2 in this comparative example is as follows:

[0125] The tin-antimony coating gel prepared in step S1 was evenly coated on the surface of the titanium foam, placed in a forced air drying oven, and dried at a temperature of 110°C for 20 minutes. It was then placed in a muffle furnace at a temperature of 250°C for thermal oxidation for a duration of 10 minutes. The above process was repeated 15 times, with the last heating at a temperature of 550°C for 1 hour to obtain a titanium foam anode material with a tin-antimony coating.

[0126] Comparative Example 4

[0127] This comparative example adopts the same preparation method as that of Example 13, except that, in step S2, the number of layers of the tin-antimony coating gel solution coated on the surface of the titanium foam is different. Specifically, the coating process of the tin-antimony coating gel solution in step S2 in this comparative example is as follows:

[0128] The tin-antimony coating gel prepared in step S1 was evenly coated on the surface of the titanium foam, placed in a blast drying oven, and dried at a temperature of 110°C for 20 minutes. It was then placed in a muffle furnace at a temperature of 250°C for thermal oxidation for a duration of 10 minutes. The above process was repeated 10 times, wherein the last heating was at a temperature of 450°C for 1 hour to obtain a titanium foam anode material with a tin-antimony coating.

[0129] Comparative Example 5

[0130] This comparative example adopts the same preparation method as Example 2, except that, in step S1, the ratio of Sn salt and Sb salt as raw materials and the concentration of the raw material solution are different. Specifically, step S1 in this comparative example is:

[0131] S1. Dissolve citric acid and n-butanol (15 mL) in a molar ratio of 1:5 in 5 mL of anhydrous ethanol, stir evenly in a constant temperature water bath at 60°C to obtain a mixed solution a.

[0132] 3.159 g SnCl4·5H2O and 0.514 g SbCl3 (the molar ratio of SnCl4·5H2O to SbCl3 is 4:1) were dissolved in 30 mL of anhydrous ethanol to obtain a mixed solution c, in which Sn 4+ The concentration of HCl was 0.3 mol / L, 5 mL of 1 mol / L HCl was added as a hydrolysis and polycondensation catalyst, and ultrasonication was performed for 30 min until the solution was ultrasonically uniform to obtain a mixed solution b.

[0133] The mixed solution a and the mixed solution b were mixed evenly, and ultrasonicated in an ultrasonic instrument until the solution was clear. The clear solution was aged for 2 hours to obtain a tin-antimony coating gel.

[0134] Comparative Example 6

[0135] This comparative example adopts the same preparation method as Example 2, except that, in step S1, the ratio of Sn salt and Sb salt as raw materials and the concentration of the raw material solution are different. Specifically, step S1 in this comparative example is:

[0136] S1. Dissolve citric acid and n-butanol (15 mL) in a molar ratio of 1:5 in 5 mL of anhydrous ethanol, stir evenly in a constant temperature water bath at 60°C to obtain a mixed solution a.

[0137] 3.159 g SnCl4·5H2O and 0.082 g SbCl3 (the molar ratio of SnCl4·5H2O to SbCl3 is 25:1) were dissolved in 30 mL of anhydrous ethanol to obtain a mixed solution c, in which Sn 4+ The concentration of HCl was 0.3 mol / L, 5 mL of 1 mol / L HCl was added as a hydrolysis and polycondensation catalyst, and ultrasonication was performed for 30 min until the solution was ultrasonically uniform to obtain a mixed solution b.

[0138] The mixed solution a and the mixed solution b were mixed evenly, and ultrasonicated in an ultrasonic instrument until the solution was clear. The clear solution was aged for 2 hours to obtain a tin-antimony coating gel.

[0139] Experimental Example 1

[0140] This experimental example tested the titanium foam anode materials prepared in each of the above examples and comparative examples. Specifically, the prepared titanium foam anode materials were used as catalytic anodes for electrocatalytic oxidation degradation of phenol. The COD removal rate was measured with a reaction time of 1.5 hours, and the electrode life was calculated using an accelerated life calculation method. The results are shown in the following table:

[0141] COD removal rate (%) Calculation of electrode life (h) Example 1 57.6 412 Example 2 86.75 552 Example 3 83.52 543 Example 4 85.06 547 Example 5 72.7 552 Example 6 93.6 840 Example 7 89.8 656 Example 8 61.67 460 Embodiment 9 71.67 640 Example 10 82.75 563 Example 11 74.58 504 Example 12 79.17 660 Example 13 87.08 884 Example 14 75.83 612 Example 15 81.25 596 Example 16 72.5 516 Comparative Example 1 58.5 460 Comparative Example 2 64.17 572 Comparative Example 3 72.5 668 Comparative Example 4 54.58 292 Comparative Example 5 62.64 391 Comparative Example 6 46.41 427

[0142] Comparison of Examples 2 to 5, and Comparative Examples 5 and 6, reveals that when the molar ratio of Sn salt to Sb salt is controlled between 9 and 19:1, a COD removal rate exceeding 70% and a calculated electrode life exceeding 540 hours can be achieved. However, when the Sn salt ratio is above or below the above range, both the COD removal rate and the calculated electrode life decrease significantly.

[0143] By comparing Examples 2, 6 and 7, it can be seen that the Sn in the mixed solution c 4+ When the concentration of Sn is controlled at 0.1-0.3 mol / L, a higher COD removal rate and electrode life can be obtained. By comparing Examples 1 and 5 with Comparative Example 1, it can be seen that if Sn 4+ The concentration is too low. Under the same number of coating layers, the total weight of the loaded tin-antimony coating is too low, which leads to poor COD removal rate and calculated electrode life.

[0144] By comparing Examples 8 to 10 with Comparative Example 2, it can be seen that when the final thermal oxidation time is controlled within 1-1.5 hours, the COD removal rate and the calculated electrode life are high, indicating good catalytic activity and stability. The optimal solution is to control the final thermal oxidation time to 1 hour.

[0145] Comparison of Examples 11 to 13 with Comparative Example 3 shows that when the thermal oxidation temperature is controlled at 250-450°C, the measured COD removal rate is higher, indicating better catalytic activity. However, when the temperature is further increased to 550°C, the COD removal rate decreases. The optimal solution is to control the thermal oxidation temperature at 450°C, at which the COD removal rate is the highest and the calculated electrode life is the longest.

[0146] Comparison of Examples 13 to 16 with Comparative Example 4 shows that a coating layer count of 12-20 achieves higher COD removal rates and calculated electrode lifespans. However, if the number of coating layers is too low, both the COD removal rate and calculated electrode lifespan decrease. The optimal solution is 15 coating layers, achieving the highest COD removal rate and calculated electrode lifespans.

[0147] The above description is merely a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention has been disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with this patent can make slight changes or modifications to equivalent embodiments of equivalent changes using the above-mentioned technical contents without departing from the scope of the technical solution of the present invention. The implementation schemes in the above-mentioned embodiments can also be further combined or replaced. However, any simple modifications, equivalent changes and modifications made to the above-mentioned embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the solution of the present invention.

Claims

1. A method for preparing a foamed titanium anode material having a tin-antimony coating, characterized in that: The steps include: S1. Prepare a tin-antimony coating gel solution using Sn salt and Sb salt as raw materials; S2. Coating and fixing the tin-antimony coating gel solution on the surface of the titanium foam anode to obtain a titanium foam anode material with a tin-antimony coating.

2. The method for preparing a foamed titanium anode material having a tin-antimony coating according to claim 1, characterized in that: Step S1 is specifically as follows: A catalyst is added to a mixed solution of Sn salt and Sb salt to react, and then mixed with citric acid and n-butanol, and aged to obtain a tin-antimony coating gel; Preferably, the Sn salt is selected from a chloride or sulfate of Sn, the Sb salt is selected from a chloride or sulfate of Sb, and the acid radical ions of the Sn salt and the Sb salt are the same; More preferably, the Sn salt is SnCl4·5H2O; the Sb salt is SbCl3; Preferably, the solvent of the mixed solution is selected from anhydrous ethanol, acetone, and water; More preferably, the solvent of the mixed solution is anhydrous ethanol; Preferably, the catalyst is the acid corresponding to the acid ions on the Sn salt and the Sb salt.

3. The method for preparing a foamed titanium anode material having a tin-antimony coating according to claim 2, characterized in that: The molar ratio of Sn salt to Sb salt in the mixed solution is (9-19):

1.

4. The method for preparing a foamed titanium anode material having a tin-antimony coating according to claim 2 or 3, characterized in that: In step S1, citric acid, n-butanol, and a solvent are mixed to obtain an ester substance solution, and the mixture is mixed in the form of an ester substance solution; Preferably, the solvent of the ester substance solution is selected from anhydrous ethanol, acetone, and water; More preferably, the solvent of the ester substance solution is anhydrous ethanol; Preferably, the preparation temperature of the ester substance solution is 35°C-70°C.

5. The method for preparing a foamed titanium anode material having a tin-antimony coating according to any one of claims 1 to 4, characterized in that: Step S2 is: applying the tin-antimony coating gel solution to the surface of the titanium foam anode, drying it, and then thermally oxidizing it at a preset temperature, repeating this process 10-20 times to obtain a titanium foam anode material having a tin-antimony coating; Preferably, the number of repetitions is 12-20 times; More preferably, the number of repetitions is 15 times.

6. The method for preparing a foamed titanium anode material having a tin-antimony coating according to claim 5, characterized in that: The preset temperature is 250℃-450℃; Preferably, the thermal oxidation temperature in the preset temperature is 450°C; Preferably, the duration of each thermal oxidation is 10 minutes.

7. The method for preparing a foamed titanium anode material having a tin-antimony coating according to claim 5 or 6, characterized in that: The last thermal oxidation temperature was 450°C and the thermal oxidation time was 1 h.

8. The method for preparing a foamed titanium anode material having a tin-antimony coating according to any one of claims 5 to 7, characterized in that: The titanium foam anode in step S2 is a titanium foam / TiO2-NTs composite material, which is obtained by using titanium foam as a raw material, forming TiO2-NTs on the surface by an anodic oxidation method, and then firing; Preferably, the cathode of the anodic oxidation method is selected from one of graphite, platinum, copper, iron, and titanium; Preferably, the electrolyte of the anodic oxidation method is an ethylene glycol solution of NH4F and H2O; More preferably, the electrolyte is a 0.5% wt NH4F and 2% vol H2O solution in ethylene glycol; Preferably, the anodic oxidation voltage is 10V-100V; More preferably, the anodic oxidation voltage is 50V; Preferably, the temperature of the electrolyte during the anodizing process is 20°C; Preferably, the anodizing time is 1h-3h; Preferably, the foamed titanium raw material is subjected to anodizing after surface polishing.

9. The method for preparing a foamed titanium anode material having a tin-antimony coating according to claim 8, characterized in that: The firing process is to gradually increase the temperature to 400℃-500℃ at a preset heating rate; Preferably, the preset heating rate is 2°C / min; Preferably, the firing temperature is 450°C; Preferably, the firing time is 1 hour to 3 hours.

10. A foamed titanium anode material with a tin-antimony coating prepared by the preparation method according to claims 1-9, characterized in that: The surface of the material is porous, and the raw material titanium foam used has a pore diameter ranging from 160μm to 240μm; Preferably, the air permeability of the raw material titanium foam used is less than 3000m 3 / h·m 2 kpa; Preferably, the porosity of the raw material titanium foam used is 30%-40%.

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