JPH064881B2 - Method for producing metal-supported particles - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing metal-supported particles, specifically, by subjecting specific inorganic particles to an activation treatment as a pretreatment and then a metal deposition treatment. The present invention relates to a method for efficiently producing inorganic particles carrying ultrafine metal particles.

[Problems to be Solved by Prior Art and Invention]

In general, ultrafine metal particles are produced by reducing metal salt particles with hydrogen, thermally decomposing metal carbonyl compounds or metal chlorides, or by heating and evaporating the metal in a vacuum, and then pulverizing it in a low temperature matrix. It is manufactured by the method.

However, the conventional method as described above has a drawback in that a large amount of energy and a large amount of labor are required because many steps are performed, and it is not easy to control the particle size of the obtained ultrafine metal particles.

Therefore, the present inventor has conducted earnest studies to develop a method for overcoming the above-mentioned drawbacks of the prior art and efficiently producing ultrafine metal particles having a controlled particle size by a simple operation.

[Problems to be solved by the invention]

As a result, they have found that the object can be achieved by subjecting inorganic particles such as silica and alumina to pre-activation treatment and then metal precipitation treatment. The present invention has been completed based on such findings.

That is, according to the present invention, the particle size of the primary particles is 10 mμ to 10 μm.
And a method for producing metal-supported particles, which comprises subjecting inorganic particles having a specific surface area of 1 m ² / g or more to an activation treatment as a pretreatment and then a metal deposition treatment. Is.

There are various inorganic particles used in the method of the present invention. Specifically, silica, alumina, aluminum hydroxide, titanium oxide, calcium carbonate, magnesium carbonate,
Examples include silicon nitride. Further, the particle size of the inorganic particles is usually suitable such that the particle size of the primary particles is 10 mμ to 10 μ and the particle size of the secondary particles is 50 mμ to 1000 μ. The term "primary particles" as used herein refers to the smallest single particle that can be observed with an electron microscope or the like, and the term "secondary particles" refers to the apparent particle morphology in which the primary particles are aggregated. Furthermore, it is preferable that the inorganic particles have a specific surface area of 1 m ² / g or more, particularly about ^{2 to} 250 m ² / g.

In the method of the present invention, it is necessary to subject the above-mentioned inorganic particles to an activation treatment as a pretreatment and then a metal deposition treatment.

That is, the above-mentioned inorganic particles are subjected to activation treatment as a pretreatment and then to metal deposition treatment.

Here, the activation treatment may be performed with a salt solution of palladium, gold, silver or platinum.

Further, as the metal to be subjected to the metal precipitation treatment, nickel, cobalt, iron, copper, silver and the like can be cited as preferable ones, but the metal is not limited to this, and various kinds may be selected according to the purpose.

The method of the present invention may be performed in the same manner as the electroless plating of plastic. That is, first, the above-mentioned inorganic particles are subjected to activation treatment as pretreatment to be activated, and then treated with a chemical plating solution to deposit metal particles (perform metal deposition treatment).

The activation treatment in the present invention means that a solution of a salt of palladium, gold, silver or platinum is brought into contact with the inorganic particles, and these metal salts are adsorbed on the surface of the inorganic particles, so that the subsequent metal deposition treatment is performed. Refers to a treatment that imparts catalytic activity. The pretreatment performed to activate the inorganic particles here is, for example, after treating the inorganic particles with a hydrochloric acid solution of stannous chloride,
Method of adsorbing tin ion and palladium ion to particles by treatment with a hydrochloric acid solution of palladium chloride; method of treating inorganic particles with a colloidal solution of palladium prepared by mixing tin salt, palladium salt and hydrochloric acid in appropriate proportions ;
A method of treating the inorganic particles with a solution in which a reducing agent such as hypophosphite is added to a palladium chloride solution may be used. Further, in these methods, a salt of a noble metal such as gold, silver or platinum can be used instead of palladium. The inorganic particles pretreated by such a method are washed with water, further treated with a sulfuric acid aqueous solution or the like if necessary, and washed again with water to perform metal deposition treatment with a chemical plating solution. The pre-treated inorganic particles are immersed in a plating solution containing a salt of a metal to be plated, such as copper sulfate or nickel sulfate. If necessary, various additives such as reducing agents such as sodium hypophosphite, anhydrous sodium sulfite, formaldehyde and hydroquinone and buffers such as citrate, ammonia and acetate can be added to the plating solution. .

The metal deposition treatment with the plating solution is not particularly limited as long as it is carried out in a state where the plating solution is sufficiently in contact with the inorganic particles activated by the pretreatment. Usually, the above-mentioned inorganic particles are suspended in water, the above-mentioned plating solution is added thereto, and the temperature is appropriately set within the range of room temperature to 100 ° C.
Stir for ~ 60 minutes to deposit the metal on the inorganic particles.
Here, the amount of the plating solution used is arbitrarily determined according to the particle size and yield of the target metal-supported particles. If such a chemically plated product is washed with water or the like and then dried, inorganic particles carrying ultrafine metal particles can be obtained.

According to the method of the present invention, the inorganic particles are activated by performing an activation treatment as a pretreatment, and then subjected to a metal deposition treatment to form ultrafine particles of metal in a state of being supported on the surface of the inorganic particles. However, the particle diameter of the ultrafine metal particles can be appropriately adjusted by changing the plating amount or increasing or decreasing, and can be adjusted from several Å to about 10,000 Å according to the purpose.

〔The invention's effect〕

As described above, according to the method of the present invention, the ultrafine metal particles can be produced in a state of being supported on the surface of the inorganic particles by a simple operation, and the particle size of the ultrafine metal particles can be arbitrarily controlled. You can In addition, the metal-supported particles obtained in this manner include catalysts, conductive materials,
It can be widely used in various fields such as magnetic materials and sensor materials.

〔Example〕

 Next, the present invention will be described in more detail with reference to Examples.

Example 1 Silica fine particles having an average primary particle diameter of 160Å, a secondary particle diameter of 1 to 20 μm, and a specific surface area of 200 m ² / g were used as inorganic particles, which were used as a catalyst liquid containing palladium chloride and stannous chloride (trade name). : Conditioner EPC, manufactured by Okuno Seiyaku Kogyo Co., Ltd., immersed in a mixed solution of 20 m, 30 m hydrochloric acid and 160 m water for 10 minutes and stirred,
Pretreatment was carried out by filtering and washing with water.

Next, the silica fine particles subjected to this pretreatment are treated with 300 m of water.
Electroless nickel plating solution (trade name: New Chemical Nickel, Okuno Pharmaceutical Industry Co., Ltd.) containing 36 g of nickel sulfate and a small amount of citrate, hypophosphite and ammonia in addition to 36 g of nickel sulfate. First, 300m
In addition, after the reaction was started with stirring at 43 ° C., 300 m was gradually added to deposit nickel ultrafine particles on the silica fine particles.

After the metal deposition treatment with the plating solution was completed, the particles were filtered off, washed with water, and dried to obtain silica fine particles carrying ultrafine nickel metal particles. When the particle diameter of the nickel ultrafine particles was measured by an electron microscope, it was 200 to 2000.
It was confirmed to be Å.

Example 2 In Example 1, 460 m of an electroless plating solution (trade name: Chemical Copper New # 100, Okuno Chemical Industries Co., Ltd.) containing 20 g of copper sulfate as well as a small amount of formaldehyde and tartaric acid was used as a plating solution. The same operation as in Example 1 was carried out except that the silica fine particles carrying the copper metal ultrafine particles were obtained. When the particle size of the copper ultrafine particles was measured by an electron microscope, it was confirmed to be 200 to 3000 Å.

Example 3 Nickel ultrafine particles were used in the same manner as in Example 1 except that γ-alumina particles having an average primary particle diameter of 150Å, a secondary particle diameter of 1 to 20 μm, and a specific surface area of 100 m ² / g were used as the inorganic particles. Alumina fine particles carrying γ were obtained. As a result of measurement with an electron microscope, it was confirmed that the particle size of the nickel ultrafine particles was 200 to 2000 Å.

Example 4 In the same manner as in Example 1 except that α-alumina particles having an average primary particle diameter of 1500Å, a secondary particle diameter of 1 to 10 μm and a specific surface area of 10 m ² / g were used as the inorganic particles, ultrafine nickel particles were used. Alumina fine particles carrying γ were obtained. As a result of measuring the nickel ultrafine particles with an electron microscope, it was confirmed that the particle diameter was 200 to 3000 Å.

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Claims (1)

[Claims] 1. An inorganic particle having a primary particle diameter of 10 mμ to 10 μm and a specific surface area of 1 m ² / g or more,
A method for producing metal-supported particles, which comprises performing an activation treatment as a pretreatment and then performing a metal deposition treatment.