阅读说明：本技术 一种二氧化钛包覆金属纳米材料的合成方法及其应用 (Synthesis method and application of titanium dioxide coated metal nano material ) 是由 曹洋 于 2021-08-19 设计创作，主要内容包括：本发明属于金属和二氧化钛复合纳米材料的制备技术领域,公开了一种二氧化钛包覆金属纳米材料的合成方法及其应用。该方法中金属盐与有机醇之间反应生成金属纳米粒子,同时金属盐与有机醇的氧化还原反应生成的水提供生成二氧化钛所需要的水,助于改善和优化水解反应在金属纳米粒子表面生成二氧化钛层,生成的二氧化钛层厚度较薄,为1-5纳米。通过X射线晶体学表征发现,合成的金属二氧化钛复合结构,金属呈晶化,生成二氧化钛量较少。该合成方法能够在金属表面包覆薄层二氧化钛,这种结构能够作为光催化活性组分用于光催化反应,此外还能够提高金属的抗腐蚀性。同时,由于二氧化钛的修饰层厚度较薄,因此金属保持催化反应活性,仍能够作为催化剂。(The invention belongs to the technical field of preparation of metal and titanium dioxide composite nano materials, and discloses a synthesis method and application of a titanium dioxide coated metal nano material. According to the method, metal salt and organic alcohol react to generate metal nano particles, water generated by the redox reaction of the metal salt and the organic alcohol provides water required for generating titanium dioxide, the improvement and optimization of hydrolysis reaction are facilitated, a titanium dioxide layer is generated on the surface of the metal nano particles, and the thickness of the generated titanium dioxide layer is thinner and is 1-5 nanometers. The X-ray crystallography shows that the synthesized metal titanium dioxide composite structure has less titanium dioxide generated because the metal is crystallized. The synthesis method can coat a thin titanium dioxide layer on the surface of the metal, and the structure can be used as a photocatalytic active component for photocatalytic reaction and can also improve the corrosion resistance of the metal. Meanwhile, because the thickness of the modified layer of the titanium dioxide is thin, the metal can still be used as a catalyst while the catalytic reaction activity is kept.)

1. The method for synthesizing the titanium dioxide coated metal nano material is characterized by comprising the step of coating the titanium dioxide on the surface layer of the metal nano material by a solvothermal synthesis method of glycerol and ethylene glycol.

2. The method for synthesizing titanium dioxide coated metal nano-material according to claim 1, wherein the solvent thermal synthesis comprises the following steps:

adding a metal-containing raw material and a titanium-containing organic ester raw material into a reducing solvent, heating for reaction, cooling to room temperature after the reaction is finished, and then sequentially cleaning by using absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the metal nano material with the surface coated with the thin-layer titanium dioxide.

3. The method as claimed in claim 2, wherein the metal-containing raw material comprises any one of a silver-containing raw material, a gold-containing raw material, a copper-containing raw material, a palladium-containing raw material and a platinum-containing raw material;

the titanium-containing organic ester raw material is tetrabutyl titanate and/or tetraisopropyl titanate.

4. The method for synthesizing titanium dioxide coated metal nano-material according to claim 3, wherein the silver-containing raw material is AgNO₃、AgOOCCH₃、Ag₂CO₃、AgBF₄Any one of the above;

the raw material containing gold is HAuCl₄；

The copper-containing raw material is Cu (NO)₃)₂And CuC₁₀H₁₄O₄One kind of (1);

the raw material containing palladium is Na₂PdCl₄And (NH)₄)₂PdCl₄One kind of (1);

the raw material containing platinum is H₂PtCl₆。

5. The method as claimed in claim 2, wherein the reducing solvent is an organic alcohol having reducing and coordinating abilities.

6. The method for synthesizing titanium dioxide coated metal nano-material according to claim 5, wherein the reducing agent comprises one or more of isopropanol, ethylene glycol and glycerol;

the reaction time of adding the metal-containing raw material and the titanium-containing organic ester raw material into the reducing agent is 3-24 hours.

7. The method as claimed in claim 2, wherein the metal-containing material and the titanium-containing organic ester material are added into a reducing solvent and heated to react at a temperature of 160-200 ℃.

8. The method for synthesizing titanium dioxide coated metal nano-material according to claim 2, wherein the method for solvothermal synthesis further comprises adding a surfactant to a solvothermal synthesis system to adjust the morphology of the metal nano-material;

the surfactant comprises polyvinylpyrrolidone and polyvinyl alcohol.

9. A titanium dioxide coated metal nanomaterial characterized by being prepared by the synthesis method of any one of claims 1 to 8.

10. The application of the titanium dioxide coated metal nano material is characterized in that the titanium dioxide coated metal nano material in the claim 9 is applied in the photoelectrochemical field, in particular to the application in the photoelectrocatalysis of water decomposition, carbon dioxide conversion and the like.

Technical Field

The invention belongs to the technical field of preparation of metal and titanium dioxide composite nano materials, and particularly relates to a synthesis method and application of a titanium dioxide coated metal nano material.

Background

The silver nano material has excellent carrier transmission capability and has important application in a transparent conductive electrode as a flexible device. At present, the preparation of various silver nano structures is well developed, and the technology is relatively mature. The platinum nanoparticles have excellent catalytic activity, show good affinity with oxides, and can be stably combined with the oxides, so that the platinum nanoparticles are generally used for being combined with titanium dioxide to improve the photo-generated electron-hole separation of a photocatalyst so as to improve the catalytic reaction activity. Composite materials formed by metal nanoparticles such as copper and palladium and titanium dioxide are also widely concerned and researched. The titanium dioxide material has wide application prospect of photocatalysis, and has the advantages of higher stability, better activity and the like when being used as a photocatalyst. However, when titanium dioxide is used as a photocatalyst, the photo-generated carriers have high recombination probability at sites such as material internal defects and surface defects, so that the light utilization rate is low, and a large amount of light energy cannot participate in the photocatalytic reaction process.

The composite structure of the electrophilic metal and the photoactive titanium dioxide is constructed to improve the photoelectric property of the titanium dioxide. The titanium dioxide layer modified on the surface of the metal nanoparticle by the current technology is usually hydrolyzed and deposited on the surface of the metal nanoparticle by titanate and titanium alcohol ester under alkaline conditions. The hydrolysis reaction rate is high in the process, so that the hydrolysis rate of titanium dioxide is difficult to control and the titanium dioxide generated by hydrolysis is difficult to control to deposit on the surfaces of the metal nanoparticles.

The prior art discloses the synthesis of silver-titanium dioxide core-shell structural materials in a two-step process, first synthesizing silver nanoparticles, and in the second step modifying the titanium dioxide layer by Stober hydrolysis. The Stober hydrolysis method is widely used in the preparation of core-shell structures (preparation method of nanocomposites, patent No.: CN 103120920).

Related documents report that Ag-coated TiO is synthesized in an organic solvent phase by two steps₂The core-shell structure shows excellent charge separation performance and photocatalytic activity. Two-step processes are required in such techniques, and the reaction steps are relatively complicated (J.Am.chem.Soc.2005,127,11, 3928-3934).

The prior art discloses that ultra-thin titanium dioxide coating can be achieved by atomic layer deposition techniques. This technique requires very complex professional equipment and usually only small amounts of sample preparation can be performed.

The current method does not have a proper technology capable of coating a thin titanium dioxide layer, and the common technology needs to synthesize metal nano particles firstly and then modify the titanium dioxide layer, thereby causing the steps to be complicated. Modifying titanium dioxide requires a hydrolysis environment, and therefore the process of modifying titanium dioxide typically requires the addition of water, as well as readily hydrolyzable titanium materials such as butyl titanate, titanium tetrachloride, and the like. Because the hydrolysis reaction rate of the titanium metal salt and the alcohol ester species of titanium is very high, the hydrolysis reaction process is difficult to control, and thus a composite nano material structure is difficult to form.

Disclosure of Invention

In order to solve the problems in the prior art, the invention provides a synthesis method and application of a titanium dioxide coated metal nano material.

The technical scheme adopted by the invention is as follows: the method for synthesizing the titanium dioxide coated metal nano material is characterized by comprising the step of coating the titanium dioxide on the surface layer of the metal nano material by a solvothermal synthesis method of glycerol and ethylene glycol.

The method comprises the steps of generating a metal nano material by reduction in reducing organic alcohol, hydrolyzing an esterification product of titanium by water generated in a reaction to generate titanium dioxide, and coating and modifying the generated titanium dioxide on the surface of metal in situ, so that the one-step synthesis of the metal titanium dioxide composite nano material is realized. Since the water for promoting the formation of titanium dioxide in this process is supplied by the reaction for forming metal nanoparticles, less titanium dioxide is formed, and thus a thin layer titanium dioxide-coated metal nanocomposite structure is obtained.

Preferably, the solvothermal synthesis comprises the following steps:

adding a metal-containing raw material and a titanium-containing organic ester raw material into a reducing solvent, heating for reaction, cooling to room temperature after the reaction is finished, and then sequentially cleaning by using absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the metal nano material with the surface coated with the thin-layer titanium dioxide.

Preferably, the metal-containing raw material comprises any one of a silver-containing raw material, a gold-containing raw material, a copper-containing raw material, a palladium-containing raw material and a platinum-containing raw material;

the titanium-containing organic ester raw material is tetrabutyl titanate and/or tetraisopropyl titanate.

The titanium-containing organic ester is selected as a basis for the formation of titanium dioxide by AgNO in a solvothermal process₃The reduction reaction between the titanium-containing organic ester and alcohol generates a small amount of water in situ to drive the titanium-containing organic ester to hydrolyze to generate titanium dioxide.

Preferably, the silver-containing raw material is AgNO₃、AgOOCCH₃、Ag₂CO₃、AgBF₄Any one of the above;

the raw material containing gold is HAuCl₄；

The copper-containing raw material is Cu (NO)₃)₂And CuC₁₀H₁₄O₄One kind of (1);

the raw material containing palladium is Na₂PdCl₄And (NH)₄)₂PdCl₄One kind of (1);

the raw material containing platinum is H₂PtCl₆。

Preferably, the reducing solvent is an organic alcohol having reducing and coordinating capabilities.

Preferably, the reducing agent comprises one or more of isopropanol, ethylene glycol and glycerol;

the reaction time of adding the metal-containing raw material and the titanium-containing organic ester raw material into the reducing agent is 3-24 hours.

Preferably, the metal-containing raw material and the titanium-containing organic ester raw material are added into a reducing solvent and heated for reaction, and the heating temperature is 160-200 ℃.

Preferably, the solvothermal synthesis method further comprises the step of adding a surfactant into a solvothermal synthesis system to adjust the morphology of the metal nano material;

the surfactant comprises polyvinylpyrrolidone and polyvinyl alcohol.

The surfactant is added into the solvothermal synthesis system to adjust the morphology of the metal nano material, so that the morphology of the metal nano material can be adjusted from a rod-shaped or other regular structures into nanoparticles with the particle size being remarkably reduced.

A titanium dioxide coated metal nanomaterial prepared by the synthesis method of any one of claims 1 to 8.

An application of the titanium dioxide coated metal nano material in the photoelectrochemical field, in particular to an application in photoelectrocatalysis of water decomposition, carbon dioxide conversion and the like by adopting the titanium dioxide coated metal nano material in claim 9.

The invention has the beneficial effects that:

the invention aims to develop a method for simply coating an atomic layer of titanium dioxide on the surface of a metal nano structure, and the method is used for applications such as photocatalysis, photochromism and the like. The invention provides a synthesis method of a titanium dioxide coated metal nano material, which adopts a solvothermal synthesis technology by using glycerol and ethylene glycol. In the method, water required by hydrolysis reaction of titanate to generate titanium dioxide is generated in situ in the process of synthesizing metal nanoparticles, and water generated by redox reaction between metal salt and organic alcohol provides water required by generation of titanium dioxide. Since the amount of water produced in this reaction is small, the thickness of the titanium dioxide layer produced is thin, and nano-scale uniform titanium dioxide can be formed.

Because the modified layer of titanium dioxide is thin, the metal can still contact with the reactant and be used as a catalyst. A large-area metal-titanium dioxide interface is formed in the composite nano particles, and the interface generally has stronger catalytic reaction activity. The X-ray crystallography shows that the synthesized metal titanium dioxide composite structure has good crystallization effect of metal, and does not show a crystallization diffraction peak of titanium dioxide due to less amount of the generated titanium dioxide. And verifying that the titanium dioxide in the obtained composite structure material is distributed on the surface of the metal nano particles by a related characterization technology.

Because the titanium dioxide material has larger crystal grains, carriers such as photo-generated electrons, photo-generated holes and the like are easier to be compounded in the titanium dioxide, so that the utilization rate of light is lower, and the absorbed light energy cannot be efficiently used for photocatalytic reaction. According to the invention, the thin titanium dioxide layer is modified on the surface of the metal nano particle, and the metal as an effective electron conductor can effectively avoid the composite quenching of photo-generated electrons and photo-generated holes in the photocatalytic reaction, so that the utilization rate of light energy is increased, and the activity of the photocatalytic reaction is improved.

Drawings

FIG. 1 is a scanning electron microscope schematic view of the silver nanorod-coated titanium dioxide synthesized in example 1;

FIG. 2 is a schematic representation of X-ray diffraction data of the silver nanorod-coated titanium dioxide material synthesized in example 1;

FIG. 3 is a schematic diagram of X-ray photoelectron spectroscopy data of the silver nanorod-coated titanium dioxide material synthesized in example 1.

Detailed Description

The present invention is further illustrated below with reference to specific examples. It will be appreciated by those skilled in the art that the following examples, which are set forth to illustrate the present invention, are intended to be part of the present invention, but not to be construed as limiting the scope of the present invention. The reagents used are all conventional products which are commercially available.

Example 1:

100mg of AgNO₃And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 160 ℃ for 10 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the silver nanorod material with the surface coated with the thin titanium dioxide.

As shown in FIG. 1, Ag-coated TiO was tested by scanning electron microscopy₂As a result, it was found that a uniform nanorod-shaped structure product was formed, and the Ag-coated TiO was measured by X-ray diffraction₂It was found that the material exhibited a strong Ag crystal peak due to the interface modified TiO₂In a small amount, no significant TiO was found₂Crystallization peak.

As shown in FIG. 2, it was found that Ag coated TiO was measured by X-ray photoelectron spectroscopy₂The material is made of Ag and TiO₂And (5) structural composition.

As shown in FIG. 3, the synthesized Ag-coated TiO₂The material shows excellent photoinduced charge-hole separation capability, so that the color can rapidly change from white to grey-black within one minute in an alcohol solution. In addition, the material is verified to have the property of hydrogen production by photocatalytic water decomposition through a photocatalytic experiment, and compared with Ag-TiO generated by classical modified Ag nano particles₂The photoelectric property of the sample is improved, the surface photovoltage is obviously enhanced, and the quantum efficiency is better, so the photocatalytic activity is better.

Example 2:

100mg of AgNO₃And 0.05mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 160 ℃ for 12 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the silver nanorod material with the surface coated with the thin titanium dioxide.

Example 3:

100mg of AgNO₃And 0.01mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 160 ℃ for 10 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the silver nanorod material with the surface coated with the thin titanium dioxide.

Example 4:

20mg of AgNO₃And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 160 ℃ for 6 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the silver nanorod material with the surface coated with the thin titanium dioxide.

Example 5:

100mg of AgNO₃And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 180 ℃ for 10 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the silver nanorod material with the surface coated with the thin titanium dioxide.

Example 6:

100mg of AgNO₃And 0.02mL of tetrabutyl titanate is added into 20 g of ethylene glycol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 160 ℃ for 10 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the silver nanorod material with the surface coated with the thin titanium dioxide.

Example 7:

100mg of AgNO₃0.02mL of tetrabutyl titanate, 20. mu. L H₂O is added into 20 g of ethylene glycol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 160 ℃ for 10 h.After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the silver nanorod material with the surface coated with the thin titanium dioxide.

Example 8:

100mg of AgNO₃0.02mL of tetrabutyl titanate, 50. mu. L H₂O is added into 20 g of ethylene glycol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 160 ℃ for 10 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the nano silver material with the surface coated with titanium dioxide.

Example 9:

100mg of AgNO₃And 0.02mL of tetrabutyl titanate is added into a mixed solvent of 10 g of glycerol and 10 g of isopropanol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 180 ℃ for 10 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the silver nanorod material with the surface coated with the thin titanium dioxide.

Example 10:

100mg of AgBF₄And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 160 ℃ for 10 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the silver nanorod material with the surface coated with the thin titanium dioxide.

Example 11:

100mg of AgOOCCH₃And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 160 ℃ for 10 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the nano silver material with the surface coated with the thin titanium dioxide layer.

Example 12:

100mg of Ag₂CO₃And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 160 ℃ for 10 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the nano silver material with the surface coated with the thin titanium dioxide layer.

Example 13:

100mg of AgNO₃And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 200 ℃ for 5 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the silver nanorod material with the surface coated with the thin titanium dioxide.

Example 14:

100mg of HAuCl₄And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 200 ℃ for 5 h. And after heating reaction, standing the reaction kettle, cooling to room temperature, and respectively cleaning products generated in the reaction by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the nano-gold material with the surface coated with the thin-layer titanium dioxide.

Example 15:

100mg of Cu (NO)₃)₂And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 200 ℃ for 5 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively washed by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the nano copper material with the surface coated with the thin titanium dioxide.

Example 16:

mixing 100mg of H₂PtCl₆And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution is subsequently transferred to a pressure-tight sealAnd (4) pressing the mixture in a reaction kettle, and reacting for 5 hours at 200 ℃. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the nano platinum material with the surface coated with the thin-layer titanium dioxide.

Example 17:

mixing 100mg (NH)₄)₂PdCl₄And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 200 ℃ for 5 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively washed by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the nano palladium material with the surface coated with the thin titanium dioxide layer.

Example 18:

mixing 100mg (NH)₄)₂PdCl₄And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 200 ℃ for 3 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively washed by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the nano palladium material with the surface coated with the thin titanium dioxide layer.

Example 19:

mixing 100mg (NH)₄)₂PdCl₄And 0.02mL of tetrabutyl titanate is added into 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 200 ℃ for 20 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively washed by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the nano palladium material with the surface coated with the thin titanium dioxide layer.

Example 20:

100mg of AgNO₃0.02mL of tetrabutyl titanate and 100mg of polyvinylpyrrolidone are added to 20 g of glycerol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 200 ℃ for 5 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively led to pass through absolute ethyl alcohol,And (3) cleaning with dilute hydrochloric acid and distilled water to obtain the silver nanoparticle material with the surface coated with the thin-layer titanium dioxide.

Example 21:

100mg of AgNO₃0.02mL of tetrabutyl titanate and 100mg of polyvinyl alcohol were added to 20 g of ethylene glycol and stirred uniformly. The solution was then transferred to a pressure-tight autoclave and reacted at 200 ℃ for 5 h. After heating reaction, the reaction kettle is kept stand and cooled to room temperature, and products generated in the reaction are respectively cleaned by absolute ethyl alcohol, dilute hydrochloric acid and distilled water to obtain the silver nano-particle material with the surface coated with the thin-layer titanium dioxide.

The present invention is not limited to the above alternative embodiments, and any other products in various forms can be obtained by the present invention, and the present invention is within the protection scope of the present invention. The above embodiments should not be construed as limiting the scope of the present invention, and it will be understood by those skilled in the art that modifications may be made to the technical solutions described in the above embodiments, or equivalent substitutions may be made to some or all of the technical features thereof, without departing from the scope of the present invention, and at the same time, such modifications or substitutions may not make the essence of the corresponding technical solutions depart from the scope of the embodiments of the present invention.