Process for the preparation of hydroxylated titanium dioxide and its use
By grafting hydroxyl groups onto the surface of nano-titanium dioxide and preparing hydroxylated titanium dioxide via a hydrothermal reaction, the compatibility and anaerobes of photoelectrochemical cathodic protection adhesive paste were solved, resulting in better adhesion and anaerobes, and improving the photoelectrochemical cathodic protection effect.
Patent Information
- Application Number
- CN202111646286.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-12-30
- Publication Date
- 2026-02-03
- Estimated Expiration
- 2041-12-30
AI Technical Summary
Existing titanium dioxide adhesives for photoelectrochemical cathodic protection suffer from insufficient compatibility, easy pulverization, and inadequate gas repellency, which affect their photoelectrochemical cathodic protection performance.
Hydroxylated titanium dioxide was prepared by grafting hydroxyl groups onto the surface of nano-titanium dioxide under specific conditions and carrying out a hydrothermal reaction in a KOH solution with a pH of 11–13 for 24–36 hours. This hydroxylated titanium dioxide was then used in a photoelectrochemical cathodic protection adhesive.
It improves the bonding strength between titanium dioxide and adhesive, prevents powdering, enhances anaerobic properties, and improves photoelectrochemical cathodic protection performance.
Smart Images
Figure CN116426995B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of corrosion protection technology and relates to a method for preparing anti-corrosion fillers, specifically a method for preparing hydroxylated titanium dioxide and its application. Background Technology
[0002] Hydroxylation of titanium dioxide is generally used in the biomedical and photodegradation fields to improve the adsorption capacity of titanium dioxide for supported substances and the catalytic activity of photodegradation. However, there have been no reports on the application of titanium dioxide hydroxylation to the field of photoelectrochemical cathodic protection.
[0003] However, there have been no reports to date on the application of hydroxylation reactions to corrosion protection technology; meanwhile, railway transportation plays an extremely important role in national economic development. In my country, railway-related industries are among the major users of various materials, especially metallic materials—steel. These steel structures, due to their constant exposure to the open environment, particularly in coastal and salt lake areas, suffer severe corrosion, significantly reducing their service life and directly affecting their safe operation.
[0004] Photoelectrochemical cathodic protection adhesives utilize the photoelectric properties of semiconductor materials to convert solar energy into electrical energy, thereby providing cathodic protection for metallic materials. This technology holds significant application potential. Titanium dioxide, the main component of the adhesive, is inexpensive, stable, and suitable for widespread application. However, titanium dioxide suffers from insufficient compatibility with the adhesive, leading to powdering and reduced lifespan. Furthermore, its insufficient anaerobic properties prevent the timely release of gases generated during photoelectrochemical cathodic protection, potentially covering active sites and diminishing its cathodic protection performance. Therefore, improving its performance remains a challenge. Summary of the Invention
[0005] The purpose of this invention is to solve the problems existing in the prior art and provide a method for preparing hydroxylated titanium dioxide and its application.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:
[0007] A method for preparing hydroxylated titanium dioxide involves placing raw material nano-titanium dioxide in a KOH solution with a pH of 11–13 and carrying out a hydrothermal reaction at 180–200°C for 24–36 hours to obtain hydroxylated titanium dioxide.
[0008] During the hydrothermal reaction, the volume of the reaction solution is 70-80% of the volume of the hydrothermal reactor.
[0009] The raw material, nano-titanium dioxide, is P25 nano-titanium dioxide or titanium dioxide prepared by anodic oxidation; wherein, nano-titanium dioxide has a radius of 20-25 nm.
[0010] The titanium dioxide prepared by the anodic oxidation method is a titanium dioxide nanotube array with a diameter of 150-200 nanometers and a length of 5-6 micrometers.
[0011] The method for preparing titanium dioxide by anodizing involves anolyzing clean titanium foil in an ammonium fluoride solution to obtain nano-titanium dioxide; wherein the voltage for anodizing is 60-70V and the anodizing time is 50-100min.
[0012] The amount of P25 nano titanium dioxide used is 0.1 to 0.3 grams of P25 nano titanium dioxide dispersed in every 10 ml of KOH solution; the amount of titanium dioxide prepared by the anodic oxidation method is 3 to 5 pieces.
[0013] An application of hydroxylated titanium dioxide, wherein the hydroxylated titanium dioxide prepared from nano-titanium dioxide is used as a photoelectrochemical cathodic protection adhesive.
[0014] An application of hydroxylated titanium dioxide, wherein the hydroxylated titanium dioxide prepared by anodic oxidation is used for substrate corrosion protection in photoelectrochemical cathodic protection.
[0015] The beneficial effects of this invention are:
[0016] This invention employs specific conditions to rationally graft hydroxyl groups onto the surface of nano-titanium dioxide, resulting in hydroxylated titanium dioxide with excellent adhesion to adhesives, thereby improving its photoelectrochemical cathodic protection performance; specifically:
[0017] 1. The hydroxylated titanium dioxide prepared by this invention has better bonding strength with adhesives, and the prepared photoelectrochemical cathodic protection adhesive is not prone to powdering, thus possessing long-term photoelectrochemical cathodic protection capability.
[0018] 2. The hydroxylated titanium dioxide prepared by this invention has a stronger anaerobic capacity than the unhydroxylated titanium dioxide, thus avoiding the gas generated during the photoelectrochemical cathodic protection process from covering the active sites and achieving a better cathodic protection effect. Attached Figure Description
[0019] Figure 1 The infrared spectrum of the hydroxylated titanium dioxide prepared according to the embodiments of the present invention shows a broad hydroxyl peak, proving the presence of hydroxyl groups.
[0020] Figure 2 This is a comparison of the effects of hydroxylated titanium dioxide (left) and unhydroxylated titanium dioxide (right) after bonding with adhesive paste, as provided in the embodiments of the present invention. The hydroxylated titanium dioxide exhibits better bonding performance with the adhesive paste, maintaining a paste-like consistency after bonding.
[0021] Figure 3This is a comparison diagram of the anaerobesic effects of hydroxylated titanium dioxide (left) and unhydroxylated titanium dioxide (right) provided in an embodiment of the present invention. Hydroxylated titanium dioxide exhibits super-anaerobesity. Detailed Implementation
[0022] The following examples further illustrate specific embodiments of the present invention. It should be noted that the specific embodiments described herein are merely for illustration and explanation and are not intended to limit the scope of the present invention.
[0023] In the following examples, the protected substrate is 304 stainless steel.
[0024] Example 1
[0025] Weigh 0.1 mol of potassium hydroxide and dissolve it in 100 ml of water to obtain a potassium hydroxide solution. Then add the potassium hydroxide solution dropwise to deionized water until the pH meter shows 13 to obtain an aqueous solution with a pH of 13.
[0026] Weigh 5g of commercial nano titanium dioxide (P25) and disperse it in 40ml of the above-mentioned aqueous solution with pH 13. Stir for 5 minutes to obtain a titanium dioxide dispersion.
[0027] 40 ml of titanium dioxide dispersion was transferred to a 50 ml hydrothermal reactor and reacted at 200 °C for 30 h. After the reaction, the mixture was rinsed with deionized water and dried under vacuum at 60 °C for 3 h. Hydroxylated titanium dioxide powder was obtained (see [link to product]). Figure 1 and Figure 2 ).
[0028] Depend on Figure 1 Infrared spectroscopy reveals a large number of hydroxyl groups on the surface of titanium dioxide.
[0029] Take 0.1g of hydroxylated titanium dioxide powder and unhydroxylated P25 powder and mix them with 5g of adhesive paste. Grind them thoroughly to obtain photoelectrochemical cathodic protection adhesive paste.
[0030] Depend on Figure 2 The results show that hydroxylated titanium dioxide and adhesive have a good bond and remain in paste form, while unhydroxylated titanium dioxide shows powdering when bonded to the adhesive.
[0031] Meanwhile, the potassium hydroxide solution obtained above was added dropwise to deionized water according to the above description, and the pH value of the aqueous solution was monitored with a pH meter to obtain aqueous solutions with different pH values (i.e., different pH values of 8, 9, 10, 11, 12, 13, 14).
[0032] Weigh 5g of commercial nano titanium dioxide (P25) and disperse it in 40ml of pH aqueous solution. Stir for 5 minutes to obtain titanium dioxide dispersion.
[0033] 40 ml of titanium dioxide dispersion was transferred to a 50 ml hydrothermal reactor and reacted at 200 °C for 30 h. After the reaction, the mixture was rinsed with deionized water and dried under vacuum at 60 °C for 3 h. Hydroxylated titanium dioxide was obtained as a control (see Table 1).
[0034] Weigh 0.1g of hydroxylated titanium dioxide obtained under different pH conditions and mix it with 5g of adhesive paste. Grind thoroughly to obtain photoelectrochemical cathodic protection adhesive paste. Coat the surface of 304 stainless steel with the photoelectrochemical cathodic protection adhesive paste and measure the cathodic protection potential under xenon lamp irradiation (see Table 1).
[0035] Comparison of photoelectrochemical cathodic protection performance of hydroxylated titanium dioxide prepared at different pH values and unhydroxylated titanium dioxide
[0036] Table 1
[0037]
[0038] As shown in Table 1 above, the hydroxylated titanium dioxide prepared at pH 11-13 exhibits the best photoelectrochemical cathodic protection effect. This indicates that hydrothermal treatment of titanium dioxide in aqueous solution at specific pH values is beneficial for the bonding of titanium dioxide with adhesives and also contributes to the improvement of its photoelectrochemical cathodic protection performance.
[0039] Comparative Example
[0040] Weigh 0.1 mol of potassium hydroxide and dissolve it in 100 ml of water to obtain a potassium hydroxide solution. Then add the potassium hydroxide solution dropwise to deionized water until the pH meter shows 12 to obtain an aqueous solution with a pH of 12.
[0041] Weigh 5g of commercially available nano-titanium dioxide of different sizes (sizes listed in Table 2) and disperse them in 40ml of the above-mentioned aqueous solution with pH 12. Stir for 5 minutes to obtain a titanium dioxide dispersion.
[0042] 40 ml of titanium dioxide dispersion was transferred to a 50 ml hydrothermal reactor and reacted at 200 °C for 30 h. After the reaction, the mixture was rinsed with deionized water and dried under vacuum at 60 °C for 3 h to obtain hydroxylated titanium dioxide powder.
[0043] The hydroxylated titanium dioxide obtained in the above comparative example was subjected to cathodic protection potential in accordance with the manner described in Example 1 (see Table 2).
[0044] Table 2
[0045]
[0046] As shown in Table 2 above, the materials prepared with nano-titanium dioxide of 20–25 nm (P25) exhibit the best photoelectrochemical cathodic protection performance. This indicates that hydroxylated titanium dioxide prepared with titanium dioxide of a specific size is beneficial for the bonding of titanium dioxide with adhesives and also contributes to improving the photoelectrochemical cathodic protection performance of titanium dioxide.
[0047] Example 2
[0048] Cut 0.3mm titanium foil into 1x3 cm2 titanium sheets and clean them in sequence with ethanol, acetone and deionized water.
[0049] Weigh 1.72g of ammonium fluoride and dissolve it in 50ml of water. Stir for 5 minutes, then add 450ml of ethylene glycol and stir for 3 hours.
[0050] Using a platinum electrode as the negative electrode, a titanium sheet as the anode, and ammonium fluoride solution as the electrolyte, anodize for 60 minutes, then rinse thoroughly with deionized water to obtain anodized nano-titanium dioxide.
[0051] Weigh 0.1 mol of potassium hydroxide and dissolve it in 100 ml of water to obtain a potassium hydroxide solution. Then add the potassium hydroxide solution dropwise to deionized water until the pH meter shows 11 to obtain an aqueous solution with a pH of 11.
[0052] The anodized nano-titanium dioxide prepared above was placed in a 50 ml reaction vessel, and 40 ml of the aqueous solution with a pH of 11 obtained above was added. The reaction was carried out at 180 °C for 24 h. After the reaction was completed, it was cleaned with deionized water.
[0053] Underwater air contact angle tests were conducted using the hydroxylated, anodized nano-titanium dioxide obtained above (see [link]). Figure 3 ).
[0054] Depend on Figure 3 It can be seen that the underwater air contact angle of hydroxylated titanium dioxide is close to 180°, while that of unhydroxylated titanium dioxide is about 160°; hydroxylated titanium dioxide exhibits superhydrophobicity.
Claims
1. A method for preparing hydroxylated titanium dioxide, characterized in that: The raw material nano-titanium dioxide was placed in a KOH solution with a pH of 11-13 and subjected to a hydrothermal reaction at 180-200℃ for 24-36 hours to obtain hydroxylated titanium dioxide. The raw material, nano-titanium dioxide, is P25 nano-titanium dioxide; wherein, the nano-titanium dioxide has a particle size of 20-25 nm.
2. The method for preparing hydroxylated titanium dioxide according to claim 1, characterized in that: During the hydrothermal reaction, the volume of the reaction solution is 70-80% of the volume of the hydrothermal reactor.
3. The method for preparing hydroxylated titanium dioxide according to claim 1, characterized in that: The amount of P25 nano titanium dioxide used is 0.1 to 0.3 grams of P25 nano titanium dioxide dispersed in every 10 ml of KOH solution.
4. An application of the hydroxylated titanium dioxide prepared by the method of claim 1, characterized in that: The application of hydroxylated titanium dioxide prepared using nano-titanium dioxide as a raw material according to claim 1 in photoelectrochemical cathodic protection adhesive.