JPH09278488A - Production of oxide coating film with noble metal dispersed - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a producing method of a fine noble metal particle dispersing material capable of efficiently producing a coating film, in which a fine noble metal particle such as gold is dispersed, and particularly preferable in the view point of the dispersion of the high concentration of fine noble metal particle and the control of the fine particle diameter. SOLUTION: The oxide coating film, in which the fine noble metal particle is dispersed, is produced by the producing method including a 1st process for forming a metal oxide coating film containing the noble metal in the surface of a base material by bringing treating solution containing a compound containing the noble metal and supersaturated with the metal oxide into contact with the base material such as a plate glass and a 2nd process for reducing the noble metal in the metal oxide coating film by heating, the irradiation of ultraviolet ray or the like to deposit the fine particle.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an oxide film in which noble metal fine particles are dispersed, which can be used as a coloring material utilizing the coloring of noble metal fine particles by surface plasmons and as a nonlinear optical element.

[0002]

2. Description of the Related Art The coloring of fine metal particles by surface plasmons has excellent heat resistance and weather resistance, and has been conventionally used for coloring glass and ceramics. On the other hand, fine particles of metals and semiconductors are expected to be applied as functional materials such as ultra-high-speed optical switches and optical logic elements utilizing the large non-linear optical effect of these fine particles. In order to effectively utilize the characteristics peculiar to such fine particles, each fine particle must be independent without aggregating, and for that purpose it is necessary to disperse and fix the fine particles in a matrix such as glass. Become.

As a method for producing a material in which these fine particles are dispersed, a method applying a melt quenching method, a sputtering method, a sol-gel method, an ion plating method or the like is known. For example, when the fine particles are dispersed in the glass by the melt-quenching method, the fine particle raw material is melted together with the glass raw material and then rapidly cooled to produce a glass in which the raw material elements of the fine particles are uniformly dispersed. Fine particles are deposited in the glass by heat treating the glass at an appropriate temperature. Further, in JP-A-6-191896, gold fine particles obtained by precipitating metal fine particles by heat treatment
A method of making a titania-silica based coating is disclosed.

On the other hand, as a method for forming an oxide film of silicon dioxide, titanium oxide or the like, there is known a so-called liquid phase deposition method in which a supersaturated metal oxide is deposited from a liquid phase (for example, JP-B-63). -65620, Japanese Patent Fair 7-
35268).

[0005]

The colored glass or non-linear optical element must contain noble metal fine particles at a certain concentration or more, and the particle size of the noble metal fine particles contained in the colored glass or nonlinear optical element varies depending on the use. It is preferably controlled. However, conventionally, in the generally known manufacturing method, the operation becomes complicated when trying to meet these requirements, and it is not always possible to efficiently manufacture a material in which fine particles having a desired particle size and concentration are dispersed. There wasn't.

An object of the present invention is to provide a method capable of efficiently producing a material in which noble metal fine particles are dispersed. It is another object of the present invention to provide a method for producing a precious metal fine particle dispersed material, which is preferable also from the viewpoint of dispersing high concentration precious metal fine particles and controlling the particle diameter of the fine particles.

[0007]

The present inventors have paid attention to the characteristics of the so-called liquid phase precipitation method, and have completed the present invention by applying this method. That is, the method for producing a noble metal fine particle-containing oxide coating film according to the present invention, a treatment liquid containing a compound containing a noble metal, the metal oxide is in a supersaturated state, by contacting the substrate, The method is characterized by including a first step of forming a metal oxide coating containing the noble metal on the surface and a second step of reducing the noble metal in the metal oxide coating to deposit it as fine particles.

This second step is, for example, a step of irradiating the metal oxide film produced in the first step with ultraviolet rays, and in another example, the metal oxide produced in the first step is oxidized. This is a step of heating the material coating.

When the second step is carried out by a heating step, this heating is carried out at a temperature at which the metal oxide film is crystallized, thereby reducing the noble metal and precipitating it as fine particles and at the same time forming the film. It may be crystallized, and the heating temperature is about 200 ° C to about 600 ° C.
The average particle diameter of the noble metal fine particles is 1 nm to
The thickness may be 10 nm.

[0010]

The metal oxide is not particularly limited as long as it can be formed by a so-called liquid phase deposition method, and silicon oxide, titanium oxide, zirconium oxide, indium oxide, vanadium oxide, chromium oxide, manganese oxide. , Iron oxide, cobalt oxide, nickel oxide and copper oxide, and complex oxides thereof can be used.
The metal oxide may be appropriately doped with another element.

As the treatment liquid, for example, when silicon dioxide is used as the metal oxide, a hydrosilicofluoric acid solution in which silicon oxide is supersaturated can be used. When titanium oxide is used as the metal oxide, a (NH ₄ ) ₂ TiF ₆ solution in which titanium oxide is in a supersaturated state can be used. In such a supersaturated treatment solution, the solubility of the metal oxide may be decreased to reach a supersaturation state by adjusting the temperature of the treatment solution in which the metal oxide is substantially saturated. The amount of metal oxide may be increased to reach a supersaturated state by adding H ₃ BO ₃ , Al, etc., which accelerates the decomposition of hydrosilicofluoric acid, to the saturated treatment liquid. Further, other means such as addition of water or a combination of these means may be used to reach the supersaturated state.

Noble metal elements include gold (Au) and silver (A
g), platinum group (Ru, Rh, Pd, Os, Ir, Pt)
Etc. can be used. In the present invention, basically,
These noble metal elements are added and dissolved in the treatment liquid as various compounds. Compounds include chloroauric acid, sodium chloroauric acid, potassium chloroauric acid, silver nitrate, silver sulfate,
Examples include chloroplatinic acid, sodium chloroplatinate, potassium chloroplatinate, and palladium chloride. The timing of adding the compound containing the noble metal element to the treatment liquid is not particularly limited. That is, it may be added at the time of preparing the treatment liquid in advance, or may be added immediately before performing liquid phase precipitation or after starting the precipitation.

The noble metal element is usually present in the coating in the ionic state after the first step of the present invention. In the present invention, in the second step, the noble metal ions are reduced into fine particles and dispersed in the oxide film. As the second step, which is the reduction step, as described above, heating, baking, and irradiation of ultraviolet light of the coating film can be exemplified.

The conditions for heating the coating vary depending on the type of metal oxide, the film forming conditions, the type of noble metal, the type of compound containing a noble metal element, etc. It is possible to obtain a good condition. However, since the particle size of the fine metal particles obtained differs depending on the heating temperature of the coating film, it is preferable to appropriately select the heating temperature at which the preferred particle size is obtained depending on the application. Generally, the higher the temperature, the larger the particle size. The inventor has set the heating temperature to 2
When the temperature is 00 ° C to 600 ° C, the average particle size is 1 nm to 10
It has been found that gold fine particles having a particle size of 1 nm to 5 nm are obtained when the heating temperature is 500 ° C. or less.

Further, in the present invention, by heating the coating, the state of the coating itself can be adjusted together with the precipitation of fine particles. That is, in the first step of the present invention,
The metal oxide film is usually formed as a film in an amorphous state, but by heating at a heating temperature at which the metal oxide film crystallizes. It is also possible to crystallize the film together with the precipitation of the noble metal fine particles. The inventor has
Approximately 4 when titanium oxide is used as the metal oxide film.
It was confirmed that titanium oxide was crystallized by heating at 00 ° C or higher. On the other hand, when the fine particles are deposited by irradiation with ultraviolet rays, it is possible to keep the metal coating in an amorphous state without being crystallized. Therefore, in the present invention, the fine particles are appropriately used depending on the application etc. It is preferable to select the precipitation method of.

When ultraviolet light irradiation is adopted, it is possible to perform patterning by distinguishing the ultraviolet light irradiation part and non-irradiation part by masking in advance. This patterning is a particularly effective method when the fine particle dispersed film is used for decorative purposes (for example, decorative glass).

The amount of the noble metal fine particles dispersed in the metal oxide film produced by the present invention basically depends on the amount of the compound containing the noble metal element dissolved in the treatment liquid.
The amount of this compound is preferably adjusted according to the desired properties. In the present invention, the noble metal having a desired concentration up to a high concentration can be easily incorporated into the coating film only by adjusting the amount of the above-mentioned compound portion in the treatment liquid.

The oxide thin film in which the noble metal fine particles are dispersed according to the present invention can be used not only as a colored glass or a nonlinear optical element but also as a deterioration preventing film for a lead-acid battery current collector and has a wide range of applications. Have.

[0019]

Next, the present invention will be described in detail with reference to specific examples. (Example 1) An ammonium fluorotitanate aqueous solution having a concentration of 0.10 mol / liter was prepared, and chloroauric acid was dissolved in the range of 0.10 to 1.00 mmol / liter to obtain a treatment liquid. . Next, 0.20 mol /
1 liter of boric acid was dissolved. These operations were carried out while keeping the temperature at 30 ° C. and sufficiently stirring. Immediately after preparation, add 50 mm x 25 mm x 1.1 m thickness to this solution.
The previously washed and dried soda lime silica glass of m was used as a substrate and immersed for 18 hours. Then, the glass substrate was taken out, washed and dried. A thin film showing a transparent interference color was observed in the obtained sample, and it was judged that a TiO ₂ thin film was formed.

The obtained sample was dipped in a dilute hydrochloric acid aqueous solution for a whole day and night, and the obtained solution was quantitatively analyzed by an ICP emission spectrometer (inductively coupled high frequency plasma emission spectrometer) to determine Ti and Ti contained in the coating film. The amount of Au element was estimated. The result is shown in FIG. Further, FIG. 2 shows the results converted from the results shown in FIG. 1 into the Au / Ti element ratio in the coating film. From these results, it was confirmed that gold was contained in the titanium oxide film by dissolving chloroauric acid in the treatment liquid. In addition, as the amount of chloroauric acid dissolved increases, the content ratio of gold to titanium increases. Particularly, when the concentration of chloroauric acid is 0.7 mmol / liter or more, the ratio of gold to the metal in the coating film. Was confirmed to be significantly increased.

(Example 2) In Example 1, a film was formed with a dissolved amount of chloroauric acid of 0.29 mmol / liter. However, chloroauric acid was dissolved in the same manner as in Example 1 in advance, at the same time as the preparation of the treatment liquid, and in two cases, 20 hours after the start of the formation of the titanium oxide film. In each case, the soda-lime glass substrate was immersed in 20 sheets each at the time when chloroauric acid was dissolved, and after each arbitrary time, one sheet was taken out, washed and dried to obtain a sample. . The result of analyzing the obtained sample in the same manner as in Example 1 is shown in FIG. From these results, it was confirmed that gold was contained in the oxide film immediately after the chloroauric acid was dissolved, regardless of the state of the treatment liquid in the liquid phase deposition method.

(Example 3) A sample obtained in Example 1 in which the amount of chloroauric acid dissolved was 0.29 mmol / liter was 100 ° C, 200 ° C, 300 ° C, 400 ° C, 500.
The heat treatment was performed at each temperature of ° C and 600 ° C. As a result, all the samples heat-treated at 200 ° C. or higher changed from transparent to purple. The following analyzes were performed on these samples.

First, a sample not subjected to heat treatment and 6
ESCA coatings on samples heat treated at 00 ° C.
(Electron Spectoropy for Chemical Analysis). The result of ESCA analysis for Au is shown in FIG. From this result, the peak position of 4f7 / 2 in the case where the heat treatment was not carried out was 86.1 eV, so that it was identified as Au ⁺¹ . That is, it is considered that the gold without heat treatment was transparent because it did not exist as atoms or particles but existed as monovalent ions. On the other hand, from the results of the coating after heat treatment,
Since the peak position of 4f7 / 2 is 83.8 eV,
It was identified as metallic Au. Therefore, it was confirmed that the heat treatment changed gold from the ionic state to the metallic state.

Example 4 The X-ray diffraction patterns of the coatings of all the samples except the heat treatment at 100 ° C. in Example 3 were measured. The result is shown in FIG. From this result, in all the heat-treated samples, metal Au
A peak was observed. Therefore, it was confirmed that the sample obtained in this example is in a metal state when subjected to heat treatment at a temperature of at least 200 ° C. or higher.
Further, regarding titanium oxide, a peak identified by anatase was detected at 400 ° C. or higher, and it was confirmed that the crystallites increased because the peak width narrowed with the heat treatment temperature.

Example 5 The TEM (transmission electron microscope) image of each sample after the heat treatment in Example 3 was observed.
As a result, Au particles of several nm to several tens of nm were confirmed in each case. The particle size distribution of the Au fine particles obtained from this is shown in FIG. From FIG. 6, Au was monodispersed in the sample heat-treated at a temperature up to 500 ° C., and the average particle size was 5 n.
It was m or less. Further, in the sample heat-treated at 600 ° C., Au was polydisperse, but the maximum particle size was 20 n.
It was found that the particle size was about m and was stable as a fine particle state. Since gold fine particles are precipitated as fine particles at 200 ° C. or higher, when the heating temperature is 200 ° C. to 600 ° C., gold fine particles having an average particle size of about 1 nm to 10 nm are obtained, and particularly, the heating temperature is 500 ° C. or lower. It can be seen that fine particles of gold having an average particle size of about 1 nm to 5 nm are obtained in the case of doing. Moreover, 350 nm-800 nm of each sample of Example 3
FIG. 7 shows the results of the extinction coefficient in the wavelength region of. From this, it was found that plasmon resonance absorption was confirmed in all the samples heat-treated at a temperature of 200 ° C. or higher, and the absorption peak position shifted from 550 nm to 640 nm with the heating temperature. That is, in this embodiment,
By setting the heating temperature to 600 ° C. or lower, the plasmon resonance absorption peak position can be controlled within the range of 550 nm to 640 nm.

(Example 6) In Example 1, a sample having a dissolved amount of chloroauric acid of 0.29 mmol / liter was used, and 10 mm x 10 mm was formed on the surface of the coating film at the center of the sample.
The masking tape was attached in the range of 1 and the ultraviolet light was irradiated from the coating side for 1 hour using a 100 W mercury lamp. Then, the masking tape was peeled off. As a result, the portion of the masking tape which was not irradiated with the ultraviolet light did not change in appearance, but the other portions changed to purple.

Next, the x-ray diffraction pattern of the coating was measured. From this result, in the part not irradiated with ultraviolet rays,
No peak due to Au was observed, but a peak due to Au of the metal was observed in the portion irradiated with ultraviolet rays. No clear peak was observed for titanium oxide.

(Example 7) Iron oxyhydroxide was dissolved in an aqueous solution of ammonium bifluoride to obtain 0.01 in terms of FeOOH.
The treatment liquid was adjusted to a concentration of mol / liter.
A film was formed here in the same manner as in Example 1. However, the concentration of chloroauric acid dissolved in the range of 0.05 to 0.45 mmol / liter. The obtained samples all showed a transparent orange color and were judged to be β-FeOOH thin films. The composition analysis results of the obtained film are shown in FIGS. 8 and 9. From this, it was confirmed that gold was contained in the β-FeOOH thin film by dissolving chloroauric acid in the treatment liquid. It was also confirmed that the content ratio of gold to iron increases as the amount of chloroauric acid dissolved increases.

(Example 8) In Example 7, the sample in which the amount of chloroauric acid dissolved was 0.29 mmol / l was heat-treated at each temperature of 300 ° C, 400 ° C, 500 ° C and 600 ° C. went. As a result, all the heat-treated samples turned from orange to dark brown.

For these samples, the X-ray diffraction pattern of the coating was measured. Regarding the data shown in FIG. 10, for the heat-treated sample, a peak due to α-Fe ₂ O ₃ and a peak due to Au of the metal were observed. Next, regarding the sample heat-treated at 600 ° C.,
The TEM image was observed. As a result, similarly to Example 5, fine particles of Au having a particle diameter of several nm to several tens nm were confirmed.

[0031]

INDUSTRIAL APPLICABILITY In the present invention, since the precious metal fine particle-containing coating is produced by the so-called liquid phase deposition method, the step of forming the coating can be carried out efficiently, and the precious metal is removed from the coating produced by this step. Since the fine particles are deposited, the concentration and particle size of the noble metal fine particles can be controlled easily and easily. That is, the present invention is not limited to the fact that the so-called liquid phase deposition method is suitable for forming an oxide film such as silicon dioxide and titanium oxide, and the film formed by this deposition method is a fine particle suitable for various applications. It was made by finding that it is suitable for controlling the concentration and particle size required for the design of a dispersion material, and can efficiently produce a noble metal-dispersed metal oxide coating film having a predetermined concentration and particle size. . Further, according to the present invention, it is possible to efficiently incorporate expensive noble metal into the film.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the concentration of metal (gold and titanium) and the concentration of chloroauric acid in the titanium oxide coating with dispersed gold particles produced in Example 1.

FIG. 2 is a graph showing a relationship between a metal concentration ratio (gold / titanium) and a chloroauric acid concentration in a gold fine particle-dispersed titanium oxide film produced in Example 1.

FIG. 3 is a graph showing the relationship between the gold concentration in the titanium oxide film with dispersed gold particles produced in Example 2 and the reaction time (time from the start of precipitation).

FIG. 4 is a diagram showing a result of measurement by ESCA for gold of a titanium oxide film with dispersed gold particles produced in Example 3.

FIG. 5 is a diagram showing an X-ray diffraction pattern measured for a gold fine particle-dispersed titanium oxide film produced according to Example 3.

FIG. 6 is a diagram showing a particle size distribution of gold fine particles observed by TEM for a gold fine particle-dispersed titanium oxide coating film produced in Example 3;

FIG. 7 is a diagram showing the results of measurement of the extinction coefficient in the wavelength range of 350 nm to 800 nm for the gold fine particle-dispersed titanium oxide film produced in Example 3.

8] Gold fine particle-dispersed β-F produced according to Example 7
It is a figure which shows the relationship between the density | concentration of the metal (gold and iron) in an eOOH coating, and the chloroauric acid density | concentration.

FIG. 9 is a diagram showing the relationship between the metal concentration ratio (gold / iron) and the chloroauric acid concentration in the gold fine particle-dispersed titanium oxide coating film produced in Example 7.

FIG. 10: Gold fine particle dispersed β-produced in Example 7
It is a figure which shows the X-ray-diffraction pattern measured about the FeOOH film.

Claims (5)

[Claims] 1. A metal oxide coating film containing the noble metal is formed on the surface of the base material by bringing a base material into contact with a treatment liquid containing a compound containing the noble metal and having a metal oxide in a supersaturated state. And a second step of reducing the noble metal in the metal oxide coating to precipitate as fine particles, the method for producing an oxide coating having dispersed noble metal fine particles. 2. The method for producing an oxide film in which noble metal fine particles are dispersed according to claim 1, wherein the second step is a step of irradiating the metal oxide film with ultraviolet rays. 3. The method for producing an oxide coating in which fine noble metal particles are dispersed according to claim 1, wherein the second step is a step of heating the metal oxide coating. 4. The metal oxide film is heated at a temperature at which the film is crystallized to reduce the noble metal to be precipitated as fine particles and to crystallize the film. 1. A method for producing an oxide film in which fine noble metal particles are dispersed. 5. The metal oxide coating is about 200 ° C. to about 6 ° C.
The average particle diameter of the noble metal fine particles is set to 1 nm to 10 nm by heating at 00 ° C, and the method for producing an oxide coating film containing dispersed noble metal fine particles according to claim 3 or 4, characterized in that.