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CN-122010180-A - Method for preparing rapid hydrogen-induced color mesoporous tungsten oxide film based on plasma etching technology

CN122010180ACN 122010180 ACN122010180 ACN 122010180ACN-122010180-A

Abstract

The invention relates to a method for preparing a fast hydrogen-induced color mesoporous tungsten oxide film based on a plasma etching technology. The preparation method comprises the steps of mixing an amphiphilic block copolymer template agent with a tungsten source precursor, coating the obtained sol on the surface of a substrate to construct an organic-inorganic hybrid film, then introducing oxygen-containing plasma to etch the hybrid film, and finally loading a catalyst layer on the surface of the film. The invention utilizes the synergistic effect of high-energy active particles and active oxygen species in the plasma, couples with chemical oxidation/volatilization reaction through physical bombardment, realizes the rapid removal of the organic template under the low-temperature condition, simultaneously maintains the structural integrity of the mesoporous framework, and avoids pore collapse and specific surface area loss caused by traditional high-temperature calcination. The mesoporous WO 3 film obtained by the method has a high specific surface area and rich surface active sites, and can effectively promote hydrogen diffusion and interfacial reaction kinetics, so that the coloring/fading response is remarkably accelerated, and the hydrogen electrochromic performance is improved.

Inventors

  • GUO XINGWU
  • WU XUAN
  • PENG LIMING

Assignees

  • 上海交通大学

Dates

Publication Date
20260512
Application Date
20260108

Claims (10)

  1. 1. The method for preparing the rapid hydrogen-induced chromic mesoporous tungsten oxide film based on the plasma etching technology is characterized by comprising the following steps of: S1, preparing precursor sol: Respectively dissolving a tungsten source and an amphiphilic block copolymer in a solvent to obtain a tungsten source solution and a copolymer solution, and mixing the tungsten source solution and the copolymer solution to obtain precursor sol; S2, preparation of a hybrid membrane: Depositing precursor sol on a substrate, and aging at low temperature to obtain an organic-inorganic hybrid film; s3, plasma etching: Performing plasma etching treatment on the organic-inorganic hybrid film in an oxygen-containing atmosphere, and removing the organic template by using oxygen-containing plasma to obtain an etched porous tungsten oxide film; S4, catalyst loading: And preparing a nano catalyst layer on the surface of the etched porous tungsten oxide film to obtain the hydrogen-induced discoloration mesoporous tungsten oxide film.
  2. 2. The method according to claim 1, wherein in step S1, the tungsten source comprises one or more of tungsten hexachloride, tungsten ethoxide, tungsten tetrachloride, peroxypoly-tungstic acid, ammonium tungstate, white tungstic acid; And/or, in step S1, the amphiphilic block copolymer comprises one or more of polyoxyethylene-polystyrene, polyoxyethylene-polymethyl methacrylate, polyoxyethylene-poly-2-vinylpyridine, polyoxyethylene-poly-4-vinylpyridine, polyoxyethylene-polyoxypropylene-polyoxyethylene; And/or, in step S1, the solvent of the tungsten source includes one or more of methanol, ethanol, n-propanol, isopropanol; And/or in step S1, the solvent of the amphiphilic block copolymer comprises one or more of tetrahydrofuran, chloroform, 1, 4-dioxane, N-dimethylformamide, toluene, xylene, benzene.
  3. 3. The preparation method according to claim 1, wherein in the step S1, the mass ratio of the tungsten atoms and the amphiphilic block copolymers in the tungsten source is 1 (0.2-5); And/or in the step S1, the dosage ratio of tungsten atoms in the tungsten source to the solvent is 1 g:2-15 ml; and/or in the step S1, the dosage ratio of the amphiphilic block copolymer to the solvent is 1 g:5-100 ml.
  4. 4. The method according to claim 1, wherein in step S1, the precursor sol further comprises a chelating agent, and the chelating agent comprises acetylacetone.
  5. 5. The method of claim 1, wherein in step S2, the precursor sol is deposited on the substrate by one of spin coating, lift-off, and spray coating.
  6. 6. The preparation method according to claim 1, wherein in step S2, the low-temperature aging is performed at 80-120 ℃ for 10-15 hours; and/or, in the step S2, the thickness of the obtained organic-inorganic hybrid film is 400-1000nm.
  7. 7. The method according to claim 1, wherein in step S3, the excitation source used for the plasma etching process includes one of microwave plasma, radio frequency plasma, and low frequency plasma; And/or in the step S3, the microwave power of the plasma etching is 450-1000W, the time is 3-120 min, and the working air pressure is 20-200 Pa.
  8. 8. The method according to claim 1, wherein in step S3, an etching gas is introduced during the plasma etching treatment, and the etching gas is oxygen or a gas containing oxygen; the flow rate of oxygen in the etching gas is 80-100%, and the flow rate of oxygen is 10-500 sccm.
  9. 9. The method according to claim 1, wherein in step S4, the nano-catalyst layer is prepared by vapor deposition or chemical reduction deposition; And/or in the step S4, the catalyst in the nano catalyst layer is one of Pt, pd, pt-Pd alloy and Pd-Au alloy; And/or in the step S4, the thickness of the nano catalyst layer is 1 nm-10 nm.
  10. 10. A rapid hydrochromic mesoporous tungsten oxide film prepared by the method of any one of claims 1 to 9.

Description

Method for preparing rapid hydrogen-induced color mesoporous tungsten oxide film based on plasma etching technology Technical Field The invention belongs to the technical field of functional film material preparation, and particularly relates to a method for preparing a fast hydrogen-induced mesoporous tungsten oxide (WO 3) film based on a plasma etching technology, in particular to a method for preparing a hydrogen-induced mesoporous tungsten oxide (WO 3) film with excellent response speed by removing an organic template agent through a plasma etching technology. Background Tungsten trioxide (WO 3) is an n-type semiconductor with hydrogen sensitive gasochromic properties. WO 3, after loading with platinum or palladium catalysts, gives a strong absorption of visible and near infrared light, changing the color from transparent/yellowish (bleached) to dark blue (colored) even when exposed to low concentrations of hydrogen at room temperature. After exposure to air or oxygen, the process is reversible, turning back transparent/yellowish. The unique hydrogen electrochromic property enables WO 3 to have wide application prospects in the fields of intelligent dimming glass and optical hydrogen sensors. In order to meet the requirements of practical application on the response speed and sensitivity of the sensor, researchers generally adopt amphiphilic block copolymers (such as PEO-b-PS, pluronic F127, PEO-b-P4VP and the like) as soft templates, and prepare the mesoporous WO 3 film with high specific surface area and rich pore structures by combining a sol-gel method with an Evaporation Induced Self Assembly (EISA) technology. The porous structure can obviously shorten the diffusion path of hydrogen molecules and protons, thereby improving the color-changing performance. However, in the existing mesoporous WO 3 film preparation process, the removal of the organic polymer template mainly depends on high temperature calcination heat treatment (Calcination), and calcination in an air atmosphere of 350 ℃ to 500 ℃ is usually required for several hours. This conventional method has the following significant drawbacks: (1) The shrinkage and collapse of the framework can lead to severe thermal shrinkage of the inorganic framework after long-time high-temperature treatment, which is extremely easy to cause deformation, collapse and even closure of mesoporous pore canals, greatly reduces the specific surface area and prevents the rapid diffusion of hydrogen. (2) Overgrowth of crystal grains, namely overgrowth and coarsening of WO 3 crystal grains are easy to occur at high temperature, the number of crystal boundaries is reduced, and the rapid transmission of ions is not facilitated. (3) Substrate limitations high temperature processes limit the use of flexible polymer substrates (e.g., PET, PEN, etc.) or temperature sensitive conductive glass (e.g., part of ITO/FTO), reducing the range of applications. (4) The energy consumption is high and the process period is long, in order to prevent the organic template from being decomposed violently in a short time to generate a large amount of gas to break the framework, and in order to slow down the thermal stress (avoid cracking) generated by the difference of the thermal expansion coefficients of the film and the substrate, the heat treatment process needs to strictly control the heating and cooling rate (usually as low as 1-2 ℃ per minute). The whole template removing process is usually continuous for a plurality of hours or even tens of hours, so that the production efficiency is extremely low, and the long-time high-temperature operation causes huge energy consumption, increases the preparation cost and is not beneficial to large-scale industrial production. To overcome the limitations of high temperature heat treatment, researchers have explored surface cleaning and surface activation techniques such as solvent extraction, ultraviolet-ozone (UVO) cleaning, and plasma etching techniques. The principle of the solvent extraction method is to remove the organic template by utilizing the dissolution of the organic solvent. Although the conditions are mild, organic matters embedded in the deep part of the inorganic framework are difficult to thoroughly remove, the original micro-nano structure can be damaged, the time is long, and the use of a large amount of organic solvents is dangerous and is unfavorable for environmental protection. Ultraviolet-ozone (UVO) cleaning technology breaks the chemical bonds of organic molecules with high energy ultraviolet light and combines the strong oxidizing property of ozone to oxidize and decompose the organic molecules. The method has the characteristics and advantages that the whole process is carried out at room temperature or low temperature, the framework shrinkage caused by the thermal effect can be effectively avoided, and the integrity of the mesoporous structure is well reserved. But UVO technology has limited penetration depth, is les