A method for preparing a polyaniline-titanium dioxide nanotube array composite electrode

Abstract

This invention discloses a method for preparing a polyaniline-titanium dioxide nanotube array composite electrode, comprising the following steps: (1) anodizing a titanium sheet to obtain a titanium dioxide nanotube array; (2) preparing a polyaniline solution through a polymerization reaction; (3) loading the polyaniline solution onto the surface of the titanium dioxide nanotube array through dip-coating, and drying to obtain the polyaniline-titanium dioxide nanotube array composite electrode. The preparation method of this invention can form nanotube clusters, strengthening the bonding force between the nanotubes and the substrate, and the formed nanotubes are more regular; moreover, the prepared nanotube array composite electrode can significantly improve the electrochemical and mechanical stability of polyaniline, thereby obtaining a larger capacitance and long-term charge-discharge cycle stability, and can also improve the conductivity of the TiO2 nanotube array.

Description

Technical Field

[0001] This invention relates to the field of electrochemistry, and more particularly to a method for preparing a polyaniline-titanium dioxide nanotube array composite electrode for electrostatic disinfection. Background Technology

[0002] Electrostatic disinfection is an air disinfection method that has emerged in recent years and is suitable for spaces where people gather for extended periods. It mainly involves two processes: electrostatic adsorption and negative ion disinfection. This process requires two electrodes. Kong Lingjie et al. reported a sterilization, disinfection, and ozone removal electrostatic adsorption electrode and its preparation method ([Patent] Invention Patent CN202010728422.6). This method requires two electrodes—an electrostatic dust collection electrode and a discharge electrode—to achieve the functions of adsorption and disinfection, respectively.

[0003] Supercapacitors are a new generation of energy devices, possessing not only higher power density than batteries and higher energy density than traditional dielectric capacitors, but also bridging the gap between traditional dielectric capacitors and batteries / fuel cells. The performance of supercapacitors is closely related to their electrodes. Polyaniline is a pseudocapacitive material used to prepare supercapacitor electrodes. Its advantages include high conductivity, but its disadvantages include weak electrochemical and cycling stability during charge and discharge. To improve the performance of polyaniline, it is often combined with other materials. TiO2 nanotube arrays are an ideal polyaniline support.

[0004] Titanium dioxide (TiO2) possesses advantages such as good chemical stability, low cost, low toxicity, abundant natural resources, and minimal environmental impact. Highly ordered TiO2 nanotube arrays prepared by anodic oxidation exhibit a large specific surface area, and the TiO2 nanotube arrays are tightly bonded to the metal substrate. The metal substrate can be directly used as a current collector, simplifying the electrode fabrication process and improving the utilization rate of the active material. Therefore, TiO2 nanotube arrays exhibit excellent electrochemical activity. However, TiO2 nanotube arrays suffer from poor conductivity and low electrochemical activity. Loading porous polyaniline onto the surface of the TiO2 nanotube array can significantly improve the electrochemical and mechanical stability of polyaniline, thereby achieving greater capacitance and long-term charge-discharge cycle stability. Furthermore, polyaniline also improves the conductivity of the TiO2 nanotube array. Summary of the Invention

[0005] Purpose of the invention: To address the above-mentioned shortcomings, this invention proposes a method for preparing a polyaniline-titanium dioxide nanotube array composite electrode for electrostatic disinfection, which forms nanotube clusters, strengthens the bonding force between the nanotubes and the substrate, and makes the formed nanotubes more regular.

[0006] Technical solution:

[0007] A method for preparing a polyaniline-titanium dioxide nanotube array composite electrode includes the following steps:

[0008] (1) Titanium dioxide nanotube arrays were obtained by anodizing titanium sheets;

[0009] (2) Polyaniline solution was prepared by polymerization reaction;

[0010] (3) A polyaniline solution was loaded onto the surface of a titanium dioxide nanotube array by dip-coating and drying to obtain a polyaniline-titanium dioxide nanotube array composite electrode.

[0011] Before step (1), a pretreatment step is also included: polishing the titanium sheet in a polishing solution of nitric acid: hydrochloric acid: water = 1:2:2 for 20 seconds, taking it out, washing it with deionized water, and drying it to remove the oxide layer on the surface of the titanium sheet.

[0012] In step (1), the process of anodizing the titanium sheet to obtain a titanium dioxide nanotube array specifically involves:

[0013] Ammonium fluoride (2-5% by mass) and water (2% by mass) are added to a glycerol solution, and then pretreated titanium sheets are placed in the solution at an intensity of 80-120 mA / cm². 2 Under constant current anodizing conditions for 30 minutes, the cathode for the anodizing reaction was a pretreated titanium sheet of the same size as described above.

[0014] In step (1), the process of anodizing the titanium sheet to obtain a titanium dioxide nanotube array specifically involves:

[0015] Titanium sheets with the oxide film removed are placed in a glycerol solution containing 2-5% ammonium fluoride, 1% phosphoric acid, and 2% water by mass, at a pressure of 30-60 mA / cm². 2 Under constant current anodizing conditions, the titanium sheet is anoly oxidized for 1-2 hours; the anoly oxidized titanium sheet is then removed and washed with deionized water.

[0016] Step (1) further includes a post-processing step: the titanium sheet after anodizing is taken out, washed with deionized water, and the oxide film is removed by ultrasonic cleaning for 10 minutes; and the titanium dioxide nanotube array is obtained by calcination at 350°C for 3 hours.

[0017] The preparation of polyaniline solution by polymerization reaction in step (2) is as follows:

[0018] (21) To prepare a 1.0 mol / L hydrochloric acid solution or phosphoric acid solution, weigh 15 g of ammonium persulfate (APS) and add it to 200 mL of a 1.0 mol / L hydrochloric acid solution or phosphoric acid solution. Stir well to obtain solution A and place it in a refrigerator to pre-cool at 0-5°C for 20 minutes.

[0019] (22) Add 4 mL of aniline to 800 mL of 1.0 mol / L hydrochloric acid solution or phosphoric acid solution and stir continuously for 30 min to obtain solution B;

[0020] (23) Add solution A to solution B at a rate of one drop every 3 to 5 seconds. After the addition is complete, place the resulting solution on a magnetic stirrer and stir for 6 to 12 hours to obtain a polyaniline solution.

[0021] The immersion and lifting coating in step (3) specifically involves immersing and lifting the titanium dioxide nanotube array obtained in step (1) in the polyaniline solution obtained in step (2) at a speed of 10-50 μm / min and for 10-50 times.

[0022] In step (3), the drying process specifically involves drying the titanium dioxide nanotube array after impregnation and dip coating at 70°C for 12 hours to obtain the final titanium dioxide nanotube array composite electrode.

[0023] Beneficial effects: The preparation method of the present invention can form nanotube clusters, strengthen the bonding force between nanotubes and substrates, and the formed nanotubes are more regular; and the prepared nanotube array composite electrode can effectively improve the electrochemical stability and mechanical stability of polyaniline, thereby obtaining a larger capacitance and long-term charge-discharge cycle stability, and can also improve the conductivity of TiO2 nanotube array. Attached Figure Description

[0024] Figure 1 This is a flowchart of the present invention.

[0025] Figure 2 The surface morphology of the polyaniline-titanium dioxide nanotube array composite electrode prepared by the preparation method of the present invention is shown.

[0026] Figure 3 for Figure 2 A magnified view of a portion of the image, in which Figure 3 (a) and Figure 3 (b) respectively represent Figure 2 Enlarged views of parts at different resolutions. Detailed Implementation

[0027] The present invention will be further explained below with reference to the accompanying drawings and specific embodiments.

[0028] The preparation method of the polyaniline-titanium dioxide nanotube array composite electrode of the present invention includes the following steps:

[0029] (1) Polish the titanium sheet in a polishing solution of nitric acid: hydrochloric acid: water = 1:2:2 for 20 seconds, take it out, wash it with deionized water, and air dry it to remove the oxide layer on the surface of the titanium sheet.

[0030] (2) Add 2-5% ammonium fluoride and 2% water to a glycerol solution, then place the titanium sheet treated in step (1) into the solution, and heat at 80-120 mA / cm. 2 Under constant current anodizing conditions for 30 min, the cathode of the anodizing reaction is a titanium sheet of the same size as the one treated in step (1) mentioned above;

[0031] In this invention, the anodizing step can also be performed as follows: the titanium sheet after the oxide film has been removed in step (1) is placed in a glycerol solution containing 2-5% ammonium fluoride, 1% phosphoric acid, and 2% water by mass, at an A / cm² temperature of 30-60. 2 Under constant current anodizing conditions, the titanium sheet is anoly oxidized for 1-2 hours; the anoly oxidized titanium sheet is then removed and washed with deionized water.

[0032] (3) Take out the titanium sheet after anodizing in step (2), wash it with deionized water, and then remove the oxide film by ultrasonic cleaning for 10 minutes, so that the prepared nanotubes are more regular.

[0033] (4) The sample obtained in step (3) is calcined at 350°C for 3 hours to obtain the calcined sample, which is the titanium dioxide nanotube array; the amorphous titanium dioxide is converted into anatase type so that it can conduct electricity and have electrochemical activity.

[0034] (5) Preparation of polyaniline solution;

[0035] (51) To prepare a 1.0 mol / L hydrochloric acid solution, weigh 15 g of ammonium persulfate (APS) and add it to 200 mL of 1.0 mol / L hydrochloric acid solution. Stir well to obtain solution A and place it in a refrigerator to pre-cool at 0-5°C for 20 minutes.

[0036] (52) Add 4 mL of aniline to 800 mL of 1.0 mol / L hydrochloric acid solution and stir continuously for 30 min to obtain solution B;

[0037] (53) Slowly add solution A to solution B at a rate of one drop every 3 to 5 seconds. After the addition is complete, place the resulting solution on a magnetic stirrer and stir for 6 to 12 hours.

[0038] In this invention, hydrochloric acid solution can be replaced with phosphoric acid solution;

[0039] (6) Immersion and lifting coating: The titanium dioxide nanotube array obtained in step (4) is immersed and lifted in the polyaniline solution obtained in step (5) at a speed of 10-50 μm / min and a number of times of 10-50 times; In this invention, the immersion and lifting speed and number of times are set according to actual needs;

[0040] (7) The titanium dioxide nanotube array after being impregnated and coated in step (6) is dried at 70°C for 12 hours to obtain the final titanium dioxide nanotube array composite electrode. In this invention, the drying temperature and time in this step are set according to actual needs.

[0041] This invention first prepares a titanium dioxide nanotube array through an anodic oxidation reaction and then calcines it at 350°C; then, a polyaniline solution is prepared through a polymerization reaction, and the polyaniline solution is loaded onto the surface of the titanium dioxide nanotube array through dip-coating, and then dried to obtain a polyaniline-titanium dioxide nanotube array composite electrode.

[0042] Figure 2 and Figure 3 The images shown are, respectively, magnified views of the surface morphology and corresponding resolution of the polyaniline-titanium dioxide nanotube array composite electrode prepared by the method of this invention. Figure 2 , 3 As shown, the nanotubes formed by the polyaniline-titanium dioxide nanotube array composite electrode prepared by the preparation method of the present invention are more regular and arranged.

[0043] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details of the above embodiments. Within the scope of the technical concept of the present invention, various equivalent transformations (such as quantity, shape, position, etc.) can be made to the technical solution of the present invention, and these equivalent transformations all fall within the protection scope of the present invention.

Claims

1. A method for preparing a polyaniline-titanium dioxide nanotube array composite electrode, characterized in that: Includes the following steps: (1) Titanium dioxide nanotube arrays are obtained by anodizing titanium sheets; (2) Polyaniline solution is prepared by polymerization reaction; (3) A polyaniline solution was loaded onto the surface of a titanium dioxide nanotube array by dip-coating and drying to obtain a polyaniline-titanium dioxide nanotube array composite electrode. Before step (1), a pretreatment step is also included: polishing the titanium sheet in a polishing solution of nitric acid: hydrochloric acid: water = 1:2:2 for 20 seconds, taking it out, washing it with deionized water, and drying it to remove the oxide layer on the surface of the titanium sheet. In step (1), the titanium sheet is anodized to obtain a titanium dioxide nanotube array. Specifically, ammonium fluoride with a mass percentage concentration of 2-5% and water with a mass percentage of 2% are added to a glycerol solution, and then the pretreated titanium sheet is placed in it. The titanium sheet is anodized under constant current at 80-120 mA / cm2 for 30 min. The cathode of the anodizing reaction is a pretreated titanium sheet of the same size as described above. Step (1) also includes a post-processing step: the titanium sheet after anodizing is taken out, washed with deionized water, and the oxide film is removed by ultrasonic cleaning for 10 minutes; it is then calcined at 350°C for 3 hours to obtain a titanium dioxide nanotube array. The specific steps of step (2) are as follows: (21) Prepare a 1.0 mol / L hydrochloric acid solution or phosphoric acid solution. Weigh 15 g of ammonium persulfate (APS) and add it to 200 mL of a 1.0 mol / L hydrochloric acid solution or phosphoric acid solution. Stir until uniform to obtain solution A. Place it in a refrigerator and pre-cool it at 0-5°C for 20 minutes. (22) Add 4 mL of aniline to 800 mL of 1.0 mol / L hydrochloric acid solution or phosphoric acid solution and stir continuously for 30 min to obtain solution B; (23) Add solution A to solution B dropwise at a rate of one drop every 3 to 5 seconds. After the addition is complete, place the obtained solution on a magnetic stirrer and stir for 6 to 12 h to obtain polyaniline solution. The immersion-coating process in step (3) specifically involves immersing the titanium dioxide nanotube array obtained in step (1) in the polyaniline solution obtained in step (2) at a speed of 10–50 μm / min and for 10–50 cycles. Second-rate; In step (3), the drying process specifically involves drying the titanium dioxide nanotube array after impregnation and dip coating at 70°C for 12 hours.

2. The method for preparing the polyaniline-titanium dioxide nanotube array composite electrode according to claim 1, characterized in that... In step (1), the method of obtaining titanium dioxide nanotube array by anodizing titanium sheet is replaced by: placing the titanium sheet after removing the oxide film into a glycerol solution containing 2-5% ammonium fluoride, 1% phosphoric acid and 2% water by mass, and anodizing it under constant current at 30-60 mA / cm2 for 1-2 hours; then taking out the anodized titanium sheet and washing it with deionized water.

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