CN111040500A

CN111040500A - Synthesis of Ag-MnO by sol-gel methodxMethod for nano-compounding thin films

Info

Publication number: CN111040500A
Application number: CN201911257065.3A
Authority: CN
Inventors: 姚伯龙; 范世龙; 温焱焱; 王露; 曾婷; 王利魁
Original assignee: Jiangnan University
Current assignee: Jiangnan University
Priority date: 2019-12-10
Filing date: 2019-12-10
Publication date: 2020-04-21
Anticipated expiration: 2039-12-10
Also published as: CN111040500B

Abstract

Synthesis of Ag-MnO by sol-gel method_xA method for nano-compounding a film belongs to the technical field of functional coatings. Under the conditions of room temperature and magnetic stirring, silver nitrate, manganese acetate and a complexing agent in a certain proportion are dissolved in absolute ethyl alcohol; the resulting mixture was kept under stirring until a dark blue dark sol was produced; putting the obtained sol in a drying oven, and evaporating part of ethanol to obtain concentrated sol; adding organic film-forming agent into the concentrated sol, and dip-coating Ag-MnO at room temperature_xDepositing a thin film on a support; drying and annealing the coated liquid film to obtain Ag-MnO_xA nanocomposite film. The Ag-MnO without impurity phase synthesized by the invention_xAn absorbing film which can achieve high absorption and low emission in the UV-VIS-IR band; the invention has simple preparation process, utilizes the existing chemicals and does not need complex equipment.

Description

Synthesis of Ag-MnO by sol-gel methodxMethod for nano-compounding thin films

Technical Field

The invention relates to a method for synthesizing Ag-MnO by a sol-gel method_xA method for nano-compounding a film belongs to the technical field of functional coatings.

Background

Today, the most widely used industrial solar selective absorbers are metal particles in (metal) ceramic structures, which are mostly produced by electrochemical or vacuum deposition methods. Notable examples include black chromium (Cr-Cr) plating₂O₃) And anode Al of nickel₂O₃(synthesized by electroplating/electrochemical method) and evaporated titanium nitride film (TiNO)_x) And nickel-nickel oxide (Ni-NiO)_x) (synthesized by vacuum deposition/sputtering method). Electrochemical treatment methods are relatively simple and have low operating temperatures, but the above methods utilize large amounts of materials and are not environmentally friendly. The vacuum deposition method has low material consumption, good repeatability and low environmental pollution, but has high investment cost of production equipment, high energy consumption in production and low cost benefit. Solar absorbers are the latest advances in selective synthesis, and such materials with high selectivity and durability require a correspondingly cost-effective and environmentally friendly synthesis process. The sol-gel technique meets the above criteria and is a very promising technique. However, solar selective absorber materials produced by such techniques have not been used in industry.

In the past decades, various solar selective absorbers, such as copper oxide-based absorbers, cobalt oxide-based absorbers, black transition metals having a spinel-like structure, and oxides of carbon-silica nanocomposites, etc., have been successfully manufactured by a sol-gel method. However, the synthesis of cermet coatings using sol-gel processes is relatively rare in known cases.

Disclosure of Invention

The invention aims to overcome the defects and provide a method for synthesizing Ag-MnO by a sol-gel method_xThe method of nano-composite film, which produces a solar absorbing film with spectral selectivity by a one-step sol-gel process, can greatly reduce the requirements of the device.

The technical scheme of the invention is that Ag-MnO is synthesized by a sol-gel method_xThe nanometer composite film is prepared through dissolving silver nitrate, manganese acetate and complexing agent in certain proportion in anhydrous alcohol via magnetic stirring at room temperature; the resulting mixture was kept under stirring until a dark blue dark sol was produced; putting the obtained sol in a drying oven, and evaporating part of ethanol to obtain concentrated sol; adding organic film-forming agent into the concentrated sol, and dip-coating Ag-MnO at room temperature_xDepositing a thin film on a support; drying and annealing the coated liquid film to obtain Ag-MnO_xA nanocomposite film.

The method comprises the following steps:

(1) preparing sol: dissolving silver nitrate, manganese acetate and a complexing agent in absolute ethyl alcohol at room temperature under the condition of magnetic stirring; the concentration of silver nitrate is 0.1-0.3mol/L, the concentration of manganese acetate is 0.1-0.5mol/L, and the addition amount of a complexing agent is 0.5-4 times of the concentration of silver particles; the resulting mixture was kept under stirring for 1-2h until a dark blue dark sol was produced; concentrating the obtained sol in a drying oven at 65-75 ℃ for 8-12h to obtain concentrated sol;

(2) deposition: adding 0.1-20% of organic film forming agent into the sol according to the mass of the sol obtained in the step (1); dip coating Ag-MnO at room temperature at a pull rate of 6-10cm/min_xThe film is deposited on a clean carrier;

(3) film forming: drying the liquid film coated in the step (2) at 70-80 ℃ for 10-30min, and heating to 200-500 ℃ at a heating rate of 1-10 ℃/min.

The complexing agent in the step (1) is specifically tetraethylenepentamine TEPA or diethanolamine DEA.

The content of manganese ions in the step (1) is excessive compared with that of silver.

The organic film forming agent in the step (2) is hydroxypropyl cellulose HPC or hydroxypropyl methyl cellulose HPMC.

The solar energy absorption powder with spectral selectivity is prepared in one step by a sol-gel method. Synthetic Ag-MnO_xThe nano composite film can be applied to a solar energy absorber. Ag nanoparticles are grown in a semiconducting matrix of manganese oxide to form Ag-MnO_xThe oxide has a similar structure to the cermet coating; after the film forming agent is doped, the reaction is carried out to form a selective absorption film. The film has better light absorption in the wavelength range of 250-2500 nm. One of the most important advantages of this method is that the entire preparation process including the heat treatment can be carried out in air, thus greatly reducing the equipment requirements.

The invention has the beneficial effects that: the Ag-MnO synthesized by the invention_xThe absorption film can simultaneously achieve high absorption and low emission in an ultraviolet-visible light-near infrared band; and the preparation process is simple, the raw materials are easy to obtain, the process is simple, and the requirement on equipment is low. The Ag-MnO_xThe film is used for spectrum selective absorption in a solar heat energy conversion system, and has a huge application prospect.

Drawings

FIG. 1 shows Ag-MnO obtained in example 1₂Absorption curve of metal oxide powder.

Detailed Description

Example 1

(1) Preparing sol: silver nitrate was first dissolved in absolute ethanol at 20 c, and then manganese acetate was added to the solution. The concentration of manganese ions in the ethanol solution is controlled to be 0.2 mol/L. The molar ratio of silver nitrate to manganese acetate was adjusted to 0.6 to suit the optical properties of the resulting film. In the solution, Diethanolamine (DEA) was used as a complexing agent, and the amount added was 0.5 times the concentration of silver particles; the desired amount of the desired product was added slowly with magnetic stirring. The resulting mixture was kept under stirring for 1h until a dark blue dark sol was produced, which was heated in an oven at 70 ℃ to obtain a concentrated sol.

(2) Deposition: about 0.4 wt% hydroxypropyl cellulose (HPC) was added to the above sol to achieve long-term stability of the sol and to obtain an optimal viscosity for dip deposition. Using dip coating technique, adding Ag-MnO at room temperature at a pull rate of 8cm/min₂The glue was deposited on a well-cleaned support SS-304.

(3) Film forming: the coated liquid film was dried at 80 ℃ for 20min and annealed at 500 ℃ for 0.5h with a heating rate of 1 ℃/min. All samples were subjected to only dip/anneal cycles.

Drying part of the sol prepared in the step (1) at high temperature, grinding and crushing to obtain Ag-MnO₂The metal oxide powder was subjected to a light absorption test, and the test results are shown in fig. 1.

As is evident from FIG. 1, it can be seen that there is a strong peak in the UV-visible-near infrared band, and it can be preliminarily concluded that Ag-MnO was prepared by a sol-gel one-step method₂The powder has excellent selective absorption function. Accordingly, their corresponding Ag-MnO₂The nano composite film also has excellent selective absorption function.

Claims

1. Synthesis of Ag-MnO by sol-gel method_xA method of nano-compounding a film, characterized by: under the conditions of room temperature and magnetic stirring, dissolving silver nitrate, manganese acetate and a complexing agent in a certain proportion in absolute ethyl alcohol; the resulting mixture was kept under stirring until a dark blue dark sol was produced; putting the obtained sol in a drying oven, and evaporating part of ethanol to obtain concentrated sol; adding organic film-forming agent into the concentrated sol, and dip-coating Ag-MnO at room temperature_xDepositing a thin film on a support; drying and annealing the coated liquid film to obtain Ag-MnO_xA nanocomposite film.

2. Synthesis of Ag-MnO according to the sol-gel method of claim 1_xThe method for preparing the nano composite film is characterized by comprising the following steps of:

3. Synthesis of Ag-MnO according to the sol-gel method of claim 2_xA method of nano-compounding a film, characterized by: the complexing agent in the step (1) is specifically tetraethylenepentamine TEPA or diethanolamine DEA.

4. Synthesis of Ag-MnO according to the sol-gel method of claim 2_xA method of nano-compounding a film, characterized by: the content of manganese ions in the step (1) is excessive compared with that of silver.

5. Synthesis of Ag-MnO according to the sol-gel method of claim 2_xA method of nano-compounding a film, characterized by: the organic film forming agent in the step (2) is hydroxypropyl cellulose HPC or hydroxypropyl methyl cellulose HPMC.