A composite film of metal foil loaded with nano strontium titanate and a preparation method and application thereof

Abstract

The application provides a metal foil loaded nano strontium titanate composite film and a preparation method and application thereof. The preparation method comprises the following steps: (1) dispersing pre-processed strontium titanate nano powder in a first solvent, and then adding a surfactant to obtain a suspension; (2) adding the suspension obtained in step (1) drop by drop along the wall of a container into a second solvent which is immiscible with the first solvent, and then performing a film forming operation, so that the liquid surface of the second solvent is dispersed with a layer of closely arranged single-layer nano strontium titanate particles; (3) loading the layer of single-layer nano strontium titanate particles on a pre-processed metal foil by using scheme a or scheme b, and obtaining the metal foil loaded nano strontium titanate composite film through post-processing. The metal foil loaded nano strontium titanate composite film provided by the application has the advantages of high temperature resistance, anti-aging, long service life and the like, and improves the utilization rate of solar energy and the carrier separation efficiency of the strontium titanate nano material.

Description

Technical Field

[0001] The invention belongs to the field of catalytic materials and relates to a metal foil-loaded nano-strontium titanate composite film, in particular to a metal foil-loaded nano-strontium titanate composite film and a preparation method and application thereof. Background Art

[0002] Strontium titanate nanomaterial is a perovskite-type semiconductor material with a band gap of 3.2eV and strong redox ability. It has a wide range of applications in photovoltaic and photocatalytic fields, such as photoelectric conversion, hydrogen production, and degradation.

[0003] Strontium titanate has a low utilization rate of solar energy, and its intrinsic photocatalytic activity is limited by the separation efficiency of photogenerated carriers. Researchers have mainly improved it through methods such as doping, loading, and compounding. Under irradiation with ultraviolet light at a wavelength of 350-360nm, the external quantum efficiency of Al-doped strontium titanate for photocatalytic water splitting can reach 96%.

[0004] Metal crystals are formed by densely packed metal atoms, bound together by metallic bonds. They contain a large number of freely moving electrons. This electron cloud is the primary reason for the high electrical conductivity of metals. Free electrons form an electron cloud that absorbs light of any wavelength and then releases light of a specific wavelength. This is the mechanism responsible for the metallic luster of metals. Most metals are silvery white because they reflect the vast majority of visible light. Only a few metals have specific colors: gold is yellow, copper is crimson, cesium is pale yellow, bismuth is pale red, and lead is pale blue. Aluminum, tin, and lead are the metals that best reflect UV light.

[0005] Therefore, metal reflective films have high reflectivity values ​​and are used for applications that enhance the reflection of light waves with wavelengths ranging from 250nm to above 10μm. For example, aluminum reflective films are used to enhance the reflection of visible light (400-650nm) or ultraviolet light (250nm-400nm).

[0006] When metal contacts a p-type semiconductor, a Schottky junction is formed. It is a simple interface between metal and semiconductor. Similar to a PN junction, it has the rectifying property of unidirectional conduction.

[0007] Currently, methods for preparing thin films on substrates primarily include sputtering, evaporation, electroplating, and chemical plating. These processes all deposit a thin metal film on a semiconductor substrate and are widely used in fields such as semiconductor devices and solar cells. However, these processes are unable to achieve a controlled, regular arrangement of strontium titanate nanoparticles, and no method has been reported for loading densely packed strontium titanate nanoparticles onto a metal film. Summary of the Invention

[0008] To address the shortcomings of existing technologies, the present invention aims to provide a metal foil-loaded nano-strontium titanate composite film, its preparation method, and its application. This invention loads a layer of densely packed strontium titanate nanoparticles onto an ultrathin metal foil. By leveraging the metal foil's high conductivity and reflectivity, as well as the Schottky junction formed with strontium titanate, the strontium titanate nanomaterial improves its solar energy utilization and carrier separation efficiency.

[0009] To achieve this object, the present invention adopts the following technical solutions:

[0010] In a first aspect, the present invention provides a method for preparing a composite film of metal foil loaded with nano-strontium titanate, the preparation method comprising the following steps:

[0011] (1) dispersing the pretreated strontium titanate nanopowder in a first solvent, and then adding a surfactant to obtain a suspension;

[0012] (2) adding the suspension obtained in step (1) dropwise along the wall of the container into a second immiscible solvent, and then performing a film-forming operation so that a tightly packed single-layer nano-strontium titanate particle layer is dispersed on the liquid surface of the second solvent;

[0013] (3) using scheme a or scheme b to load a nano-strontium titanate film on the pretreated metal foil, and obtaining a composite film of the metal foil loaded with nano-strontium titanate through post-treatment;

[0014] The method a comprises: placing the metal foil below the liquid surface from the side of the second solvent in step (2), and lifting it horizontally from bottom to top from below the nano-strontium titanate particle layer, thereby forming a tightly packed single-particle layer of strontium titanate thin film on the surface of the metal foil;

[0015] The scheme b comprises: bringing the metal foil into horizontal contact with the liquid surface of the second solvent in step (2), pressing it horizontally into the solution and then fishing it out, forming a tightly arranged single-particle layer of strontium titanate film on the surface of the foil.

[0016] The present invention utilizes the interfacial tension of the gas-solid interface film to load a layer of tightly arranged strontium titanate nanoparticles on an ultra-thin metal foil, and utilizes the high conductivity and high reflectivity of the metal foil and the Schottky junction characteristics formed with strontium titanate to improve the utilization rate of solar energy and the carrier separation efficiency of the strontium titanate nanomaterial.

[0017] The metal foil-loaded nano-strontium titanate composite film provided by the present invention has advantages such as high temperature resistance, aging resistance, and long life. Sunlight reflected by the metal foil is absorbed and converted again by the strontium titanate nanomaterial. Each particle is directly in contact with the metal foil and is densely arranged. The composite film with the metal foil can rapidly separate charge carriers and achieve a higher transmission rate. It has applications in perovskite solar cells and photocatalytic water splitting for hydrogen production.

[0018] In the suspension of step (2) of the present invention, the strontium titanate nanopowder is dispersed in the form of single particles.

[0019] As a preferred technical solution of the present invention, the pretreatment in step (1) includes any one or a combination of at least two of ultrasonic dispersion, planetary ball milling, stirring or chemical metal plating. Typical but non-limiting combinations include a combination of ultrasonic dispersion and planetary ball milling, a combination of ultrasonic dispersion and chemical metal plating, or a combination of planetary ball milling and chemical metal plating.

[0020] Preferably, the average particle size of the strontium titanate nanopowder in step (1) is 20 to 100 nm, for example, it can be 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm or 100 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0021] Preferably, the morphology of the strontium titanate nanopowder in step (1) includes any one or a combination of at least two of spherical, near-spherical, cubic, plate-like or polyhedron. Typical but non-limiting combinations include a combination of spherical and near-spherical, a combination of cubic and plate-like, a combination of cubic and polyhedron, a combination of spherical, near-spherical and polyhedron, or a combination of spherical, near-spherical, cubic, plate-like and polyhedron.

[0022] The preparation method of the cubic strontium titanate nanopowder is: NaCl-KCl molten salt method.

[0023] The preparation method of the nearly spherical strontium titanate nanopowder is: a hydrothermal method.

[0024] The preparation method of the polyhedral strontium titanate nanopowder is: solid phase synthesis method.

[0025] Preferably, the strontium titanate nanopowder in step (1) is doped with metal elements.

[0026] Preferably, the metal element includes any one or a combination of at least two of Cu, Al, Au, Pd, or Pt. Typical but non-limiting combinations include a combination of Cu and Al, a combination of Au, Pd, and Pt, or a combination of Cu, Al, Au, Pd, and Pt.

[0027] Preferably, the solid content concentration of the strontium titanate nanopowder in the first solvent in step (1) is 0.2 to 1.2 g / L, for example, it can be 0.2 g / L, 0.4 g / L, 0.6 g / L, 0.8 g / L, 1 g / L or 1.2 g / L, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0028] Preferably, the first solvent comprises ethyl acetate and / or butanol.

[0029] Preferably, the amount of the surfactant added in step (1) is 0.1-0.5% of the mass of the strontium titanate nanopowder, for example, it can be 0.1%, 0.2%, 0.3%, 0.4% or 0.5%, but is not limited to the listed values. Other values ​​not listed within the numerical range are also applicable.

[0030] Preferably, the surfactant in step (1) includes an ionic dispersant and / or an organic dispersant.

[0031] Preferably, the ionic dispersant includes any one or a combination of at least two of sodium hexadecyl sulfonate, potassium dihydrogen phosphate or sodium citrate. Typical but non-limiting combinations include a combination of sodium hexadecyl sulfonate and potassium dihydrogen phosphate, a combination of potassium dihydrogen phosphate and sodium citrate, a combination of sodium hexadecyl sulfonate and sodium citrate, or a combination of sodium hexadecyl sulfonate, potassium dihydrogen phosphate and sodium citrate.

[0032] Preferably, the organic dispersant includes any one or a combination of at least two of polyacrylic acid amine, oleic acid or phosphate ester. Typical but non-limiting combinations include a combination of polyacrylic acid amine and oleic acid, a combination of oleic acid and phosphate ester, a combination of polyacrylic acid amine and phosphate ester, or a combination of polyacrylic acid amine, oleic acid and phosphate ester.

[0033] Preferably, the dropwise addition rate in step (2) is 40 to 80 drops / min, for example, 40 drops / min, 50 drops / min, 60 drops / min, 70 drops / min or 80 drops / min, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0034] Preferably, the end point of adding the suspension in step (2) is when the liquid surface of the second solvent is filled with dispersed particles.

[0035] Preferably, the second solvent in step (2) comprises any one of water, chloroform or anhydrous ethanol, or a combination of at least two thereof. Typical but non-limiting combinations include a combination of water and chloroform, a combination of water and anhydrous ethanol, a combination of chloroform and anhydrous ethanol, or a combination of water, chloroform and anhydrous ethanol.

[0036] Preferably, the film forming operation in step (2) includes adding alcohol dropwise into the side wall of the container, or placing a hot plate into the side wall of the container.

[0037] Preferably, the temperature of the hot plate is 50-100°C, for example, 50°C, 60°C, 70°C, 80°C or 100°C, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0038] Preferably, the thickness of the metal foil in step (3) is 0.01-0.1 mm, for example, 0.01 mm, 0.02 mm, 0.05 mm, 0.08 mm or 0.1 mm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0039] Preferably, the metal foil in step (3) comprises any one of copper foil, aluminum foil, titanium foil or hand-torn steel.

[0040] Preferably, the pretreatment in step (3) includes any one or a combination of at least two of cleaning treatment, reduction treatment, electrolytic activation, oxide film corrosion removal treatment or preservation treatment under a protective atmosphere.

[0041] Preferably, the scheme b in step (3) further comprises adding a film-forming agent to the first solvent in advance.

[0042] Preferably, the added amount of the film-forming agent is 5-10% of the mass of the first solvent, for example, it can be 5%, 6%, 7%, 8%, 9% or 10%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0043] Preferably, the film-forming agent includes any one or a combination of at least two of an acrylic resin film-forming agent, a butadiene resin film-forming agent or a polyurethane film-forming agent. Typical but non-limiting combinations include: a combination of an acrylic resin film-forming agent and a butadiene resin film-forming agent, a combination of an acrylic resin film-forming agent and a polyurethane film-forming agent, a combination of a butadiene resin film-forming agent and a polyurethane film-forming agent, or a combination of an acrylic resin film-forming agent, a butadiene resin film-forming agent and a polyurethane film-forming agent.

[0044] Preferably, the post-treatment in step (3) includes any one of reduction or drying or a combination of at least two.

[0045] As a preferred technical solution of the present invention, the method for preparing a metal foil-loaded nano-strontium titanate composite film provided in the first aspect of the present invention comprises the following steps:

[0046] (1) dispersing strontium titanate nanopowder having an average particle size of 20 to 100 nm after pretreatment in a first solvent, and then adding a surfactant to obtain a suspension;

[0047] The strontium titanate nanopowder is doped with metal elements; the solid content concentration of the strontium titanate nanopowder in the first solvent is 0.2 to 1.2 g / L; the amount of the surfactant added is 0.1 to 0.5% of the mass of the strontium titanate nanopowder;

[0048] (2) adding the suspension obtained in step (1) dropwise into the second solvent along the wall of the container at a rate of 40 to 80 drops / min until the liquid surface of the second solvent is full of dispersed particles, and then performing a film forming operation so that a tightly arranged single-layer nano-strontium titanate particle layer is dispersed on the liquid surface of the second solvent;

[0049] The film forming operation includes adding alcohol dropwise into the side wall of the container, or placing a hot plate at 50-100°C into the side wall of the container;

[0050] (3) using scheme a or scheme b to load a nano-strontium titanate film on a metal foil having a thickness of 0.01-0.1 mm after pretreatment, and obtaining a composite film of the metal foil loaded with nano-strontium titanate after post-treatment;

[0051] The method a comprises: placing the metal foil below the liquid surface from the side of the second solvent in step (2), and lifting it horizontally from bottom to top from below the nano-strontium titanate particle layer, thereby forming a tightly packed single-particle layer of strontium titanate thin film on the surface of the metal foil;

[0052] The scheme b comprises: bringing the metal foil into horizontal contact with the liquid surface of the second solvent in step (2), and then pressing it horizontally into the solution and then fishing it out, forming a tightly arranged single-particle layer of strontium titanate film on the surface of the foil.

[0053] In a second aspect, the present invention provides a metal foil-loaded nano-strontium titanate composite film, wherein the metal foil-loaded nano-strontium titanate composite film is obtained by the preparation method provided in the first aspect.

[0054] In a third aspect, the present invention provides an application of a metal foil-loaded nano-strontium titanate composite film obtained by the preparation method provided in the first aspect, wherein the metal foil-loaded nano-strontium titanate composite film is used in the photovoltaic and / or photocatalytic fields.

[0055] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0056] Compared with the prior art, the present invention has the following beneficial effects:

[0057] (1) The metal foil-loaded nano-strontium titanate composite film provided by the present invention has the advantages of high temperature resistance, anti-aging, and long service life;

[0058] (2) The metal foil-loaded nano-strontium titanate composite film provided by the present invention can absorb and convert sunlight reflected by the metal foil into strontium titanate nanomaterials again, and each particle is in direct contact with the metal foil and arranged closely;

[0059] (3) The composite of nano-strontium titanate and metal foil in the metal foil-loaded nano-strontium titanate composite film provided by the present invention can enable rapid separation of carriers and have a higher transmission rate, and can be applied to fields such as perovskite solar cells and photolysis of water to produce hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 and Figure 2 This is an electron microscope image of the metal foil-loaded nano-strontium titanate composite film provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0061] The technical solution of the present invention will be further described below with reference to the accompanying drawings and through specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0062] This embodiment provides a metal foil-loaded nano-strontium titanate composite film. The preparation method of the metal foil-loaded nano-strontium titanate composite film comprises the following steps:

[0063] (1) Pre-treated cubic strontium titanate nanopowder with an average particle size of 50 nm was dispersed in n-butanol, and then sodium hexadecyl sulfate was added to obtain a suspension;

[0064] The solid content concentration of the strontium titanate nanopowder in the first solvent is 0.2 g / L; the amount of the surfactant added is 0.1% of the mass of the strontium titanate nanopowder;

[0065] The pretreatment is chemical metal plating, which includes the following steps:

[0066] ① Adding SnCl2 solution to cubic strontium titanate nanopowder for sensitization treatment, then performing PdCl2 activation treatment, and obtaining the first strontium titanate nanopowder after washing;

[0067] ② mixing the chemical copper plating solution, the formaldehyde solution and the first strontium titanate nanopowder obtained in step ①, magnetically stirring at 50° C. for 1 hour, separating and washing the powder to obtain partially copper-plated strontium titanate nanopowder;

[0068] (2) adding the suspension obtained in step (1) dropwise into water along the wall of the container at a rate of 50 drops / min, with white particles dispersed and floating on the liquid surface and continuously expanding toward the water surface until the liquid surface is full of dispersed particles, and then performing a film-forming operation, so that a tightly arranged single-layer nano-strontium titanate particle layer is dispersed on the liquid surface of the second solvent;

[0069] The film-forming operation includes adding alcohol dropwise into the container, whereby the dispersed particles gradually aggregate under the action of surface tension to form a tightly packed film;

[0070] (3) Using scheme a, a nano-strontium titanate film is loaded on a copper foil with a thickness of 0.05 mm after pretreatment, and a composite film of the metal foil loaded with nano-strontium titanate is obtained after post-treatment;

[0071] The method a comprises: placing the metal foil below the liquid surface from the side of the second solvent in step (2), and lifting it horizontally from bottom to top from below the nano-strontium titanate particle layer, thereby forming a densely arranged single-particle layer of nano-strontium titanate thin film on the surface of the metal foil;

[0072] The pretreatment includes: protecting the copper foil in a nitrogen atmosphere;

[0073] The post-treatment includes: drying and reduction treatment in a hydrogen environment at 550° C.

[0074] The electron microscope image of the metal foil provided in this embodiment is as follows: Figure 1 and Figure 2 shown.

[0075] Example 2

[0076] This embodiment provides a metal foil-loaded nano-strontium titanate composite film. The preparation method of the metal foil-loaded nano-strontium titanate composite film comprises the following steps:

[0077] (1) Dispersing pretreated, nearly spherical strontium titanate nanopowder having an average particle size of 20 to 100 nm in ethyl acetate, and then adding polyacrylamide to obtain a suspension;

[0078] The strontium titanate nanopowder is doped with Al element; the solid content concentration of the strontium titanate nanopowder in the first solvent is 0.5g / L; the amount of the surfactant added is 0.2% of the mass of the strontium titanate nanopowder;

[0079] The pretreatment comprises: ultrasonically dispersing the strontium titanate nanopowder for 30 minutes;

[0080] (2) adding the suspension obtained in step (1) dropwise into water along the wall of the container at a rate of 40 drops / min, with white particles dispersed and floating on the liquid surface and continuously expanding toward the water surface until the liquid surface is full of dispersed particles, and then performing a film-forming operation, so that a tightly arranged single-layer nano-strontium titanate particle layer is dispersed on the liquid surface of the second solvent;

[0081] The film forming operation includes placing a hot plate at 100°C in the container;

[0082] (3) Using scheme a, a nano-strontium titanate film is loaded on an aluminum foil with a thickness of 0.05 mm after pretreatment, and a composite film of the metal foil loaded with nano-strontium titanate is obtained after post-treatment;

[0083] The method a comprises: inserting the metal foil from the side of the second solvent in step (2) below the liquid surface, and lifting it horizontally from bottom to top from below the nano-strontium titanate film, thereby forming a densely arranged single-particle layer of strontium titanate film on the surface of the metal foil;

[0084] The pretreatment comprises: cutting the aluminum foil in a nitrogen-protected glove box, placing the aluminum foil in an alkaline solution to remove the oxide layer on the surface, cleaning the aluminum foil, and drying the aluminum foil;

[0085] The post-treatment includes vacuum calcination at 400°C.

[0086] Example 3

[0087] This embodiment provides a metal foil-loaded nano-strontium titanate composite film. The preparation method of the metal foil-loaded nano-strontium titanate composite film comprises the following steps:

[0088] (1) dispersing pretreated polyhedral strontium titanate nanopowder having an average particle size of 20 to 100 nm in water, and then adding sodium hexadecyl sulfate to obtain a suspension;

[0089] The solid content concentration of the strontium titanate nanopowder in the first solvent is 0.3 g / L; the amount of the surfactant added is 0.3% of the mass of the strontium titanate nanopowder;

[0090] The pretreatment comprises: ball milling the strontium titanate nanopowder for 2 hours and ultrasonically dispersing the powder for 30 minutes;

[0091] (2) adding the suspension obtained in step (1) dropwise into chloroform along the wall of the container at a rate of 80 drops / min, with white particles dispersed and floating on the liquid surface and continuously expanding until the liquid surface is full of dispersed particles, and then performing a film-forming operation, so that a tightly arranged single-layer nano-strontium titanate particle layer is dispersed on the liquid surface of the second solvent;

[0092] The film forming operation includes adding alcohol dropwise into the container, or placing a hot plate at 100° C. into the container;

[0093] (3) Scheme a was used to load a nano-strontium titanate film on hand-torn steel with a thickness of 0.02 mm after pretreatment, and a composite film of the metal foil loaded with nano-strontium titanate was obtained after post-treatment;

[0094] The method a comprises: inserting the metal foil from the side of the second solvent in step (2) below the liquid surface, and lifting it horizontally from bottom to top from below the nano-strontium titanate film, thereby forming a densely arranged single-particle layer of strontium titanate film on the surface of the metal foil;

[0095] The pretreatment includes: electrolytic activation, cleaning and drying;

[0096] The post-treatment is: calcination treatment.

[0097] Example 4

[0098] This embodiment provides a metal foil-loaded nano-strontium titanate composite film. The preparation method of the metal foil-loaded nano-strontium titanate composite film comprises the following steps:

[0099] (1) Pre-treated polyhedral strontium titanate nanopowder with an average particle size of 20 to 100 nm is dispersed in alcohol, and then sodium hexadecyl sulfate is added to obtain a suspension;

[0100] The solid content concentration of the strontium titanate nanopowder in the first solvent is 0.4 g / L; the amount of the surfactant added is 0.2% of the mass of the strontium titanate nanopowder;

[0101] The pretreatment comprises: ball milling the strontium titanate nanopowder for 2 hours, ultrasonically dispersing the powder for 30 minutes, and then washing the powder;

[0102] (2) adding the suspension obtained in step (1) dropwise into the second solvent along the wall of the container at a rate of 60 drops / min until the liquid surface of the second solvent is full of dispersed particles, and then performing a film forming operation so that a tightly arranged single-layer nano-strontium titanate particle layer is dispersed on the liquid surface of the second solvent;

[0103] The film forming operation includes placing a hot plate at 50°C in the container;

[0104] (3) using scheme a to load a nano-strontium titanate film on a metal titanium layer with a thickness of 0.1 mm after pretreatment, and obtaining a composite film of the metal foil loaded with nano-strontium titanate after post-treatment;

[0105] The method a comprises: placing the metal foil below the liquid surface from the side of the second solvent in step (2), and lifting it horizontally from bottom to top from below the thin layer of nano-strontium titanate particles, thereby forming a tightly packed single-particle layer of strontium titanate thin film on the surface of the metal foil;

[0106] The preparation method of the metal titanium foil is as follows: a metal titanium layer with a thickness of 0.1 mm is plated on a silicon oxide substrate with a roughness of less than 20 nm by a magnetron sputtering method;

[0107] The post-treatment is: oxidation calcination treatment.

[0108] Example 5

[0109] This embodiment provides a metal foil-loaded nano-strontium titanate composite film. The preparation method of the metal foil-loaded nano-strontium titanate composite film differs from that of Example 4 only in that:

[0110] In this embodiment, the scheme a described in step (3) is modified into scheme b, that is, the metal foil is horizontally contacted with the liquid surface of the second solvent in step (2), and then horizontally pressed into the solution and then removed, forming a tightly arranged single-particle layer of strontium titanate film on the surface of the foil.

[0111] Performance testing:

[0112] The metal foil-loaded nano-strontium titanate composite film provided in the above embodiment was subjected to a high temperature resistance test in air.

[0113] The composite film of nano-strontium titanate loaded on the metal foil provided in the above embodiment was prepared as a catalyst and used for hydrogen production by photohydrolysis, and its hydrogen production rate was measured.

[0114] The high temperature detection results and hydrogen production rate results are shown in Table 1.

[0115] Table 1

[0116] High temperature resistance / ℃ <![CDATA[Hydrogen production rate / μmol / (s·m 2 )]]> Example 1 400 2 Example 2 350 20 Example 3 800 5 Example 4 600 25 Example 5 600 18

[0117] In summary, the present invention utilizes the interfacial tension of the gas-solid interface film to load a layer of tightly arranged strontium titanate nanoparticles on an ultra-thin metal foil, and utilizes the high conductivity and high reflectivity of the metal foil and the Schottky junction characteristics formed with strontium titanate to improve the utilization rate of solar energy and the carrier separation efficiency of the strontium titanate nanomaterial.

[0118] The applicant declares that the present invention is intended to illustrate the detailed structural features of the present invention through the above-described embodiments, but the present invention is not limited to the above-described detailed structural features. This does not mean that the present invention must rely on the above-described detailed structural features in order to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for selected components, additions of auxiliary components, and selection of specific embodiments, etc., fall within the scope of protection and disclosure of the present invention.

[0119] The applicant declares that the present invention uses the above-described embodiments to illustrate the detailed process flow of the present invention, but the present invention is not limited to the above-described detailed process flow, that is, it does not mean that the present invention must rely on the above-described detailed process flow to be implemented. Those skilled in the art should understand that any improvements to the present invention, equivalent replacements for various raw materials in the products of the present invention, addition of auxiliary ingredients, and selection of specific methods, etc., are all within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a composite film of metal foil loaded with nano-strontium titanate, characterized in that: The preparation method comprises the following steps: (1) dispersing the pretreated strontium titanate nanopowder in a first solvent, and then adding a surfactant to obtain a suspension; (2) adding the suspension obtained in step (1) dropwise along the wall of the container into a second immiscible solvent, and then performing a film-forming operation so that a tightly packed single-layer nano-strontium titanate particle layer is dispersed on the liquid surface of the second solvent; (3) Using scheme a or scheme b to load a nano-strontium titanate film on the pretreated metal foil, and obtaining a composite film of the metal foil loaded with nano-strontium titanate through post-treatment; The method a comprises: placing the metal foil below the liquid surface from the side of the second solvent in step (2), and lifting it horizontally from bottom to top from below the nano-strontium titanate single particle layer, thereby forming a tightly packed single particle layer of strontium titanate thin film on the surface of the metal foil; The method b comprises: bringing the metal foil into horizontal contact with the liquid surface of the second solvent in step (2), pressing the metal foil horizontally into the solution and then removing the metal foil, thereby forming a tightly packed single particle layer of strontium titanate thin film on the surface of the foil; The thickness of the metal foil in step (3) is 0.01-0.1 mm; The solid content concentration of the strontium titanate nanopowder in the first solvent in step (1) is 0.2-1.2 g / L; The first solvent includes ethyl acetate and / or butanol; The speed of dropwise addition in step (2) is 40 to 80 drops / min; Step (2) the second solvent comprises any one of water, chloroform or anhydrous ethanol, or a combination of at least two thereof; The film forming operation in step (2) includes adding alcohol dropwise into the side wall of the container, or placing a hot plate into the side wall of the container; The temperature of the hot plate is 50-100°C.

2. The preparation method according to claim 1, characterized in that The pretreatment in step (1) includes any one of ultrasonic dispersion, planetary ball milling, stirring or chemical metal plating, or a combination of at least two of them.

3. The preparation method according to claim 1, characterized in that The average particle size of the strontium titanate nanopowder in step (1) is 20-100 nm.

4. The preparation method according to claim 1, characterized in that The morphology of the strontium titanate nanopowder in step (1) includes any one of spherical, nearly spherical, cubic, plate-like or polyhedral, or a combination of at least two of them.

5. The preparation method according to claim 1, characterized in that The strontium titanate nanopowder in step (1) is doped with metal elements.

6. The preparation method according to claim 5, characterized in that The metal element includes any one of Cu, Al, Au, Pd or Pt, or a combination of at least two of them.

7. The preparation method according to claim 1, characterized in that The amount of surfactant added in step (1) is 0.1-0.5% of the mass of the strontium titanate nanopowder.

8. The preparation method according to claim 1, characterized in that The surfactant in step (1) includes an ionic dispersant and / or an organic dispersant.

9. The preparation method according to claim 8, characterized in that The ionic dispersant includes any one of sodium hexadecyl sulfonate, potassium dihydrogen phosphate or sodium citrate, or a combination of at least two of them.

10. The preparation method according to claim 8, characterized in that The organic dispersant includes any one of polyacrylic acid amine, oleic acid or phosphate ester, or a combination of at least two thereof.

11. The preparation method according to claim 1, characterized in that The end point of adding the suspension in step (2) is when the liquid surface of the second solvent is filled with dispersed particles.

12. The preparation method according to claim 1, characterized in that The metal foil material in step (3) includes any one of copper foil, aluminum foil, titanium foil or hand-torn steel.

13. The preparation method according to claim 1, characterized in that The pretreatment in step (3) includes any one or a combination of at least two of cleaning treatment, reduction treatment, electrolytic activation, oxide film corrosion removal treatment or preservation treatment under a protective atmosphere.

14. The preparation method according to claim 1, characterized in that The method b further comprises adding a film-forming agent to the first solvent in advance.

15. The preparation method according to claim 14, characterized in that The added amount of the film-forming agent is 5-10% of the mass of the first solvent.

16. The preparation method according to claim 14, characterized in that The film-forming agent includes any one of an acrylic resin film-forming agent, a butadiene resin film-forming agent or a polyurethane film-forming agent, or a combination of at least two of the above.

17. The preparation method according to claim 1, characterized in that The post-treatment in step (3) includes any one of reduction, calcination or drying, or a combination of at least two of them.

18. A composite film of metal foil loaded with nano-strontium titanate, characterized in that: The metal foil-loaded nano-strontium titanate composite film is obtained by the preparation method according to any one of claims 1 to 17.

19. An application of the metal foil-loaded nano-strontium titanate composite film as claimed in claim 18, characterized in that: The metal foil-loaded nano-strontium titanate composite film is used in the photovoltaic and / or photocatalytic fields.

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