阅读说明：本技术 一种钛掺杂多级孔二氧化硅/纳米氧化钨复合电致变色薄膜的制备方法 (Preparation method of titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film ) 是由 杜晶晶 宋娅 许利剑 许建雄 于 2019-11-04 设计创作，主要内容包括：本发明公开了一种钛掺杂多级孔二氧化硅/纳米氧化钨复合电致变色薄膜的制备方法,包括以下步骤：制备复合物介晶模板、制备钛掺杂多级孔二氧化硅微球、清洗工作电极、制备电化学沉积液、恒电位沉积,制备得到钛掺杂多级孔二氧化硅/纳米氧化钨复合电致变色薄膜。本发明通过在纳米氧化钨薄膜中引入钛掺杂多级孔二氧化硅,制备的钛掺杂多级孔二氧化硅/纳米氧化钨复合电致变色薄膜相较于纯纳米氧化钨薄膜,其具有明显的多孔结构,显著提高了复合薄膜的比表面积,而且钛的引入为复合薄膜提供了活性位点,缩短了离子与电子在其内部的扩散路径,利于离子与电子的快速嵌入与脱出,有效的提高了复合薄膜的的光学调制范围、着色效率和循环稳定性。(The invention discloses a preparation method of a titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film, which comprises the following steps: preparing a compound mesomorphic template, preparing titanium-doped hierarchical porous silica microspheres, cleaning a working electrode, preparing electrochemical deposition liquid, depositing at constant potential, and preparing the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film. According to the invention, titanium-doped hierarchical porous silica is introduced into the nano tungsten oxide film, compared with a pure nano tungsten oxide film, the prepared titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film has an obvious porous structure, the specific surface area of the composite film is obviously improved, and the introduction of titanium provides an active site for the composite film, shortens the diffusion path of ions and electrons in the composite film, is beneficial to the rapid embedding and releasing of the ions and the electrons, and effectively improves the optical modulation range, the coloring efficiency and the cycling stability of the composite film.)

1. A preparation method of a titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film is characterized by comprising the following steps:

s1, preparing a compound mesomorphic template: dissolving a cationic surfactant and an anionic polyelectrolyte in molecular water to form a transparent mixed solution, and adding ammonia water into the mixed solution to obtain a compound mesomorphic template;

s2, preparing titanium-doped hierarchical porous silica microspheres: sequentially adding tetraethoxysilane and peroxotitanic acid solution into a compound mesomorphic template to form emulsion, transferring the emulsion into a drying oven for reaction, washing, drying and calcining after the reaction to remove an organic template, thereby obtaining the titanium-doped hierarchical porous silica microspheres;

s3, cleaning the working electrode: ultrasonically cleaning the FTO conductive glass in acetone, hydrochloric acid solution and ethanol respectively, and then drying the FTO conductive glass by using protective gas;

s4, preparing electrochemical deposition liquid: dissolving a tungsten source, hydrogen peroxide and nitric acid in molecular water to form a peroxytungstic acid solution, and adding titanium-doped hierarchical pore silica microspheres into the solution to obtain electrochemical deposition solution;

s5, constant potential deposition: using the FTO conductive glass cleaned in the step S3 as a working electrode, Ag/AgCl as a reference electrode, a platinum sheet as a counter electrode, performing constant potential deposition in an electrochemical deposition solution, washing with molecular water, and performing N₂And drying by blowing to obtain the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film.

2. The method for preparing the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film according to claim 1, wherein the cationic surfactant is cetylpyridinium chloride monohydrate and the anionic polyelectrolyte is polyacrylic acid in step S1.

3. The method for preparing the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film according to claim 1, wherein the method for preparing the peroxotitanic acid solution in step S2 is as follows: dissolving titanyl sulfate in molecular water, adding hydrogen peroxide at low temperature, and stirring to obtain titanyl acid solution.

4. The method for preparing the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film according to claim 1, wherein the molar ratio of titanium element in the titanium-doped hierarchical porous silica microspheres in step S2 is 0.5-5%.

5. The preparation method of the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film according to claim 4, wherein the particle size of the titanium-doped hierarchical porous silica microspheres is 500-800 nm.

6. The method for preparing the titanium-doped hierarchical pore silica/nano tungsten oxide composite electrochromic film according to claim 1, wherein the concentration of the tungsten source in the electrochemical deposition solution in the step S4 is 0.03-0.18M.

7. The method for preparing the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film according to claim 6, wherein the tungsten source is any one of sodium tungstate, tungsten powder, ammonium tungstate, ammonium metatungstate and tungsten chloride.

8. The preparation method of the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film according to claim 1, wherein the mass ratio of the tungsten source to the titanium-doped hierarchical porous silica microspheres in step S4 is 5-20: 1.

9. The titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film obtained by the preparation method according to any one of claims 1 to 8, characterized in that the electrochromic film has a porous structure with titanium-doped hierarchical porous silica microspheres as a framework.

10. The titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film according to claim 9, wherein the electrochromic film has an optical modulation range of 33.79-57.89% and a coloring efficiency of 33.49-88.84 cm at 700nm²C^-1。

Technical Field

The invention relates to the technical field of functional materials and electrochromic films, in particular to a preparation method of a titanium-doped hierarchical porous silicon dioxide/nano tungsten oxide composite electrochromic film.

Background

The electrochromic material is a special material, and under the action of an external electric field, the optical properties of the material, such as transmittance, reflectivity, absorptivity and the like, can be stably and reversibly changed. Due to the unique property, the anti-glare liquid crystal display has wide application in the fields of digital displays, automobile anti-glare rearview mirrors, intelligent windows and the like.

The tungsten oxide electrochromic material has advantages of large optical contrast, wide raw material source, low cost and the like, so that researches on the tungsten oxide electrochromic material are widely carried out by researchers. The electrochromic principle of tungsten oxide is that under the action of an external electric field, ions (Li)⁺, H⁺) And reversible oxidation (fading) reduction (coloring) reaction occurs when electrons are embedded in and removed from the tungsten oxide layer. At present, a pure tungsten oxide film generally exists in a compact structure, which is not beneficial to ion diffusion and electron transmission in an electrochromic process, so that the color change response speed of the film is slow, and the practical application of the tungsten oxide electrochromic film is limited. Chinese patent (201510881964.6) discloses a tungsten oxide electrochromic film prepared by a liquid-phase laser ablation method and an electrophoretic deposition method, and the tungsten oxide film prepared by the method has a compact structure and is not beneficial to the embedding and the extraction of ions in the electrochromic process. Chinese patent (201810727920.1) discloses a method for preparing a tungsten oxide electrochromic electrode, wherein tungsten chloride is prepared into sol, the sol is sprayed on FTO conductive glass, the tungsten oxide electrochromic electrode is obtained after further ultraviolet treatment, and the optical modulation range of the obtained film at 633 nm is only 31.74%. In general, the response time and optical contrast of tungsten oxide are controlled by the diffusion rate of ion intercalation and deintercalation, which is a diffusion process. Porous tungsten oxide filmThe tungsten oxide film has more ion diffusion channels, shorter ion diffusion paths and large specific surface area, and is beneficial to the diffusion and transmission of ions and electrons in the tungsten oxide film, thereby improving the electrochromic performance of the tungsten oxide film. Therefore, there is an urgent need to develop a simple method for preparing a tungsten oxide film having a porous structure, so as to obtain a tungsten oxide film having excellent electrochromic properties, and facilitate its application and popularization in related fields.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method of a titanium-doped hierarchical pore silica/nano tungsten oxide composite electrochromic film with a porous structure.

The invention also aims to provide the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film prepared by the preparation method.

The purpose of the invention is realized by the following technical scheme:

a preparation method of a titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film comprises the following steps:

s1, preparing a compound mesomorphic template: dissolving a cationic surfactant and an anionic polyelectrolyte in molecular water to form a transparent mixed solution, and adding ammonia water into the mixed solution to obtain a compound mesomorphic template;

s2, preparing titanium-doped hierarchical porous silica microspheres: sequentially adding tetraethoxysilane and peroxotitanic acid solution into a compound mesomorphic template to form emulsion, transferring the emulsion into a drying oven for reaction, washing, drying and calcining after the reaction to remove an organic template, thereby obtaining the titanium-doped hierarchical porous silica microspheres;

s3, cleaning the working electrode: ultrasonically cleaning the FTO conductive glass in acetone, hydrochloric acid solution and ethanol respectively, and then drying the FTO conductive glass by using protective gas;

s4, preparing electrochemical deposition liquid: dissolving a tungsten source, hydrogen peroxide and nitric acid in molecular water to form a peroxytungstic acid solution, and adding titanium-doped hierarchical pore silica microspheres into the solution to obtain electrochemical deposition solution;

s5, constant potential deposition: using the FTO conductive glass cleaned in the step S3 as a working electrode, Ag/AgCl as a reference electrode, a platinum sheet as a counter electrode, performing constant potential deposition in an electrochemical deposition solution, washing with molecular water, and performing N₂And drying by blowing to obtain the titanium-doped hierarchical porous silica/tungsten oxide composite electrochromic film.

Further, in step S1, the cationic surfactant is cetylpyridinium chloride monohydrate, and the anionic polyelectrolyte is polyacrylic acid.

Further, the method for preparing the peroxotitanic acid solution in step S2 is as follows: dissolving titanyl sulfate in molecular water, adding hydrogen peroxide at the temperature of 2-6 ℃, and stirring to obtain a titanyl acid solution.

Further, in the step S2, the molar ratio of the titanium element in the titanium-doped hierarchical porous silica microspheres is 0.5-5%.

Further, the particle size of the titanium-doped hierarchical porous silica microsphere is 500-800 nm.

Further, the concentration of the tungsten source in the electrochemical deposition solution in step S4 is 0.03-0.18M.

Further, the tungsten source is any one of sodium tungstate, tungsten powder, ammonium tungstate, ammonium metatungstate and tungsten chloride.

Further, the mass ratio of the tungsten source to the titanium-doped hierarchical porous silica microspheres in the step S4 is 5-20: 1.

Further, in the step S5, the deposition time of the constant potential deposition is 5-30 min, and the voltage is-0.3 to-0.8V.

The titanium-doped hierarchical pore silica/nano tungsten oxide composite electrochromic film obtained by the preparation method has a porous structure with titanium-doped hierarchical pore silica microspheres as a framework.

Further, the electrochromic film has an optical modulation range of 33.79-57.89% and a coloring efficiency of 33.49-88.84 cm at 700nm²C^-1。

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, the titanium-doped hierarchical pore silica microspheres are prepared by adopting a dynamic template method, so that not only can the hierarchical pore structure microspheres with a large specific surface be obtained, an effective ion and electron transmission path is provided for an electrochromic process, but also the effective active sites and firmness of titanium can be greatly improved, the use of a reducing agent in the traditional doping method is avoided, the problems of pore channel blockage due to titanium agglomeration and the like are reduced, and the process flow is simplified.

In the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film prepared by the invention, Van der Waals force between titanium-doped hierarchical porous silica microspheres and tungsten oxide particles effectively reduces the sheet resistance of the electrochromic layer, improves the conductivity of the electrochromic layer, plays a supporting role in the electrochromic layer, changes the structure of the electrochromic layer, improves the stability of a tungsten oxide material, shortens an ion diffusion path, is beneficial to embedding and releasing ions, and effectively improves the electrochemical and optical properties of the film.

The titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film prepared by the invention has the appearance of a porous structure and has excellent electrochromic performance.

Drawings

FIG. 1 is a high-power Scanning Electron Microscope (SEM) image of titanium-doped hierarchical porous silica microspheres obtained in the first example;

FIG. 2 is a scanning electron microscope image of the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film obtained in the first example;

FIG. 3 is a photo-electron spectrum a of the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film obtained in the first embodiment, a high-resolution XPS spectrum b of tungsten in the film, a high-resolution XPS spectrum c of titanium, and a high-resolution XPS spectrum d of silicon;

FIG. 4 is a cyclic voltammetry curve of the titanium doped hierarchical porous silica/nano tungsten oxide composite electrochromic film obtained in the first example;

FIG. 5 is a transmittance curve of the titanium doped hierarchical porous silica/nano tungsten oxide composite electrochromic film obtained in the first example in the colored and discolored states, and the inset is a digital photograph of the colored and discolored states;

FIG. 6 is the in-situ transmittance curve at 700nm of the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film obtained in the first example;

FIG. 7 is a scanning electron microscope image of the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film obtained in example two;

FIG. 8 is a transmittance curve of the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film obtained in example two in the colored and discolored states, and the inset is a digital photograph of the colored and discolored states;

FIG. 9 is a schematic view of the preparation process and color change principle of the titanium-doped hierarchical porous silica/nano tungsten oxide composite electrochromic film according to the present invention;

FIG. 10 is a scanning electron micrograph of an electrochromic film prepared in comparative example 1;

FIG. 11 is a scanning electron micrograph of an electrochromic film prepared in comparative example 2;

fig. 12 is a scanning electron micrograph of the electrochromic film prepared in comparative example 3.

Detailed Description

In order to facilitate understanding of the present invention, the present invention will be described in more detail with reference to the following examples, but the scope of the present invention is not limited to the following specific examples.

Unless otherwise defined, all terms of art used hereinafter have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the present invention.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by existing methods.