JP2008012426A - Catalytic body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a catalytic body which is obtained by depositing a metal having catalytic activity in micropores of an anodically-oxidized film and has excellent catalytic performance. <P>SOLUTION: The catalytic body comprises: the anodically-oxidized film which is obtained by anodically oxidizing a valve metal and has micropores; and the metal which exists in micropores and has catalytic activity. The catalytic body is characterized in that the surface area ratio obtained by dividing the actual surface area, which is obtained by measuring the surface of the catalytic body after held for 2 hours at 200°C on the side of the anodically-oxidized film by a BET method, by the geometrical surface area is within 5,000-300,000 and 10% or more of micropores existing on the surface of the catalytic body on the side of the anodically-oxidized film are straightly-tubular micropores. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a catalyst body having a catalyst supported on micropores of an anodized film.

Much attention has been paid to research on methods for producing microstructures (nanostructures) having a regular microstructure.
For example, as a method for forming a regular structure in a self-regulating manner, an anodized film obtained by subjecting aluminum to an anodizing treatment in an electrolytic solution can be mentioned. It is known that a plurality of fine pores (micropores) having a diameter of about several nm to several hundred nm are regularly formed in the anodized film. Using this self-ordering of the anodic oxide film to obtain a perfectly regular arrangement, theoretically, hexagonal prism cells with a regular hexagonal bottom surface are formed around the micropores, and adjacent micropores are formed. It is known that the connecting line forms an equilateral triangle.
Non-Patent Document 1 describes an anodized film having micropores. Non-Patent Document 2 describes that pores are spontaneously formed in the anodized film as the oxidation proceeds. Non-Patent Document 3 also proposes forming an Au dot array on a Si substrate using a porous oxide film as a mask.
The greatest feature as the material of the anodic oxide film is that a plurality of micropores adopt a honeycomb structure in which the plurality of micropores are formed in a direction substantially perpendicular to the substrate surface and in parallel at substantially equal intervals. In addition to this, the pore diameter, the pore interval, and the pore depth can be controlled relatively freely, which is a feature not found in other materials (see Non-Patent Document 3).

As an application example of the anodic oxide film, various devices such as a nano device for supporting a catalyst, an optical functional device, a magnetic device, and a light emitter are known.
As an application to the catalyst field, Patent Document 1 proposes a catalyst carrier obtained by calcining alumite. Patent Document 2 describes a method for producing a catalyst body in which a metal having catalytic activity is supported on the alumina layer after hydrothermal treatment at 50 ° C. to 350 ° C. or while performing hydrothermal treatment. Patent Document 3 proposes a method of adjusting the pore distribution by hydrating an anodized film with water or warm water. Further, Patent Document 4 describes a catalyst carrier obtained by subjecting the anodized anodized surface to a hydration treatment, a sol-gel treatment, a catalyst supporting treatment, and a firing treatment. Patent Document 5 describes a catalyst carrier obtained by enlarging the pore diameter of the anodized anodized surface formed by acid treatment on the anodized anodized surface, and then performing hydration treatment and calcination treatment.

JP 59-59247 A Japanese Patent Laid-Open No. 4-200745 JP-A-8-246190 JP-A-10-73226 JP 2002-119856 A H. Masuda et. Al. , Jpn. J. et al. Appl. Phys. , Vol. 37 (1998), pp. L1340-1342, Part 2, No. 1 11A, 1 November 1998 (FIG. 2.) “Surface Technology Handbook”, edited by Surface Technology Association (1998), Nikkan Kogyo Shimbun, p. 490-553 Hideki Masuda, “Highly Ordered Metal Nanohole Array Based on Anodized Alumina”, Solid State Physics, 1996, Vol. 31, No. 5, p. 493-499

However, as a result of studies by the present inventors, it has been found that the catalytic activity of the obtained catalyst carrier is not sufficient in the methods described in Patent Documents 1 to 5.
SUMMARY OF THE INVENTION An object of the present invention is to provide a catalyst body having a metal having catalytic activity in a micropore of an anodized film and having excellent catalytic performance.

  As a result of intensive studies to achieve the above object, the present inventors have increased the surface area ratio of the catalyst body and made a structure in which a fluid such as a liquid or a gas smoothly flows to the deep part inside the micropore. As a result, it was found that an unprecedented high performance catalyst body could be obtained, and the present invention was completed.

That is, the present invention provides the following (1) to (3).
(1) A catalyst body having an anodized film having micropores obtained by anodizing a valve metal, and a metal having catalytic activity present in the micropores,
About the surface on the anodized film side, the surface area ratio obtained by dividing the actual surface area measured by the BET method after holding at 200 ° C. for 2 hours by the geometric surface area is 5000 to 300,000,
A catalyst body in which 10% or more of the micropores existing on the surface on the anodic oxide film side are straight tubular micropores.
(2) The catalyst body according to (1), further including a valve metal member that supports the anodized film.
(3) The catalyst body according to (1) or (2), wherein the valve metal is aluminum.

  The catalyst body of the present invention is excellent in catalytic activity.

The present invention is described in detail below.
The catalyst body of the present invention is a catalyst body having an anodized film having micropores obtained by subjecting a valve metal to an anodizing treatment, and a metal having catalytic activity present in the micropores.

<Anodized film>
The anodized film can be obtained by anodizing a valve metal and has a micropore.

<Valve metal>
As the valve metal, a metal having a characteristic that the surface is covered with an oxide film of the metal by anodizing treatment can be used. Examples include aluminum, tantalum, niobium, titanium, hafnium, zirconium, zinc, tungsten, bismuth, and antimony. Among these, aluminum is preferable.

The aluminum is not particularly limited, and conventionally known aluminum or an aluminum alloy mainly composed of aluminum can be used. For example, a pure aluminum plate, an alloy plate containing aluminum as a main component and containing a trace amount of foreign elements, and low-purity aluminum (for example, a recycled material) can be used.
In the present invention, the aluminum purity is preferably 99% by mass or more, more preferably 99.5% by mass or more, and further preferably 99.9% by mass or more. As aluminum having such purity, JIS 1000 series aluminum is readily available. Examples thereof include JIS 1N00, 1200, 1100, 1N30, 1230, 1050, 1060, 1070, 1080, 1085, 1N90 and 1N99 materials.

  The anodized film can be formed by subjecting the above-described valve metal to anodization, but if necessary, degreasing treatment for cleaning the surface of the valve metal before the anodization, anode Starting point forming process for forming micropores of oxide film at a predetermined position, pore widening process for expanding the micropore diameter of anodized film formed by anodizing process, surface area increasing process for increasing surface area, etc. It can be carried out. Hereinafter, each treatment will be described by taking as an example the case of using aluminum as the valve metal.

<Degreasing treatment>
The aluminum is preferably preliminarily degreased.
Degreasing treatment uses acids, alkalis, organic solvents, etc. to dissolve and remove organic components such as dust, fat, and resin that adhere to the aluminum surface, and causes defects in each treatment described later due to the organic components. This is done for the purpose of preventing the occurrence of.
A conventionally known degreasing agent can be used for the degreasing treatment. Specifically, for example, various commercially available degreasing agents can be used by a predetermined method.

Especially, the following each method is illustrated suitably.
A method in which an organic solvent such as various alcohols (for example, methanol), various ketones, benzine, and volatile oil is brought into contact with the aluminum surface at room temperature (organic solvent method); a solution containing a surfactant such as soap or neutral detergent at room temperature A method of bringing the aluminum surface into contact with the aluminum surface at a temperature of from 80 to 80 ° C., followed by washing with water (surfactant method); a sulfuric acid aqueous solution having a concentration of 10 to 200 g / L is applied to the aluminum surface at a temperature from room temperature to 70 ° C. for 30 to 80 seconds. A method of contacting and then washing with water; a direct current having a current density of 1 to 10 A / dm ² with a sodium hydroxide aqueous solution having a concentration of 5 to 20 g / L being brought into contact with the aluminum surface at room temperature for about 30 seconds, with the aluminum surface serving as a cathode. And then neutralizing by contacting with an aqueous nitric acid solution having a concentration of 100 to 500 g / L; various known anodizing treatment electrodes While in contact with the aluminum surface a liquid at room temperature, the aluminum surface by applying a direct current of a current density of 1 to 10 A / dm ² in the cathode, or a method of electrolysis by passing an alternating current; concentration 10 to 200 g / L A method in which an aqueous alkali solution is brought into contact with an aluminum surface at 40 to 50 ° C. for 15 to 60 seconds and then neutralized by bringing a nitric acid aqueous solution having a concentration of 100 to 500 g / L into contact; surfactant, water, etc. are added to light oil, kerosene, etc. A method in which the mixed emulsion is brought into contact with the aluminum surface at a temperature from room temperature to 50 ° C. and then washed with water (emulsion degreasing method); a mixed solution of sodium carbonate, phosphates, surfactant, etc. This is a method (phosphate method) in which the aluminum surface is brought into contact with the aluminum surface for 30 to 180 seconds and then washed with water.

  The degreasing treatment is preferably a method in which the fat on the aluminum surface can be removed while aluminum is hardly dissolved. In this respect, the organic solvent method, the surfactant method, the emulsion degreasing method, and the phosphate method are preferable. Among these, the surfactant method is preferable in terms of simplicity and wastewater treatment.

<Starting point formation process>
The starting point forming process is a process for forming a starting point for forming micropores at desired positions in the anodizing process described later. In this invention, it is preferable to perform this starting point formation process.
Although the starting point to form is not specifically limited, It is preferable that it is a hollow so that formation of micropores may advance uniformly. The depression preferably has a diameter of 10 nm to 0.5 μm and a depth of 10 nm to several hundred μm. Moreover, it is preferable that the center space | interval of adjacent hollows is several tens nm to several micrometers. These can be appropriately selected according to the structure of the catalyst body.

The starting point forming method is not particularly limited, and for example, a known method can be used.
Specifically, for example, a self-regulation method using a phenomenon in which micropores formed by anodizing treatment are regularly arranged as the processing proceeds, an FIB method of creating a starting point using a focused ion beam, Examples include a photolithographic method using a microfabricated resist and a stamp method in which a regular template is prepared in advance and the pattern is transferred. Also useful is a multi-stage anodizing method in which anodizing treatment, pore widening treatment and partial anodic oxide film dissolution and removal treatment are repeated a plurality of times.
Hereinafter, the self-ordering method and the multistage anodizing method will be described as examples.

<Self-regulation method>
The self-ordering method is a method of improving the regularity by utilizing the property that the micropores of the anodized film are regularly arranged and removing the factors that disturb the regular arrangement. Specifically, high-purity aluminum is used as a substrate, an anodized film is formed at a voltage corresponding to the type of the electrolytic solution, and then a film removal process is performed.
In this method, since the pore diameter depends on the voltage, a desired pore diameter can be obtained to some extent by controlling the voltage.

The average flow rate of the electrolytic solution is preferably 0.5 to 20.0 m / min. By performing the anodizing treatment at a flow rate within this range, uniform and high regularity can be obtained. A more preferable range of the flow rate is 1.0 to 15.0 m / min, and more preferably 2.0 to 10.0 m / min.
Moreover, the method of flowing the electrolytic solution under the above-mentioned conditions is not particularly limited, but, for example, a method using a general stirring device such as a stirrer is used. Furthermore, it is more preferable to use a stirrer capable of controlling the stirring speed with a digital display because the average flow velocity can be controlled. As such a stirring apparatus, for example, a magnetic stirrer HS-50D (manufactured by ASONE Co., Ltd.) can be mentioned.

  For the anodizing treatment, for example, a method in which a substrate is used as an anode in a solution having an acid concentration of 1 to 10% by mass can be used. The solution used for the anodizing treatment is preferably an acid solution, more preferably a solution of sulfuric acid, phosphoric acid, oxalic acid, citric acid, malonic acid, tartaric acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid, A solution of sulfuric acid, phosphoric acid, oxalic acid, citric acid, malonic acid, and tartaric acid is more preferable. These are used alone or in combination of two or more.

The density | concentration of electrolyte solution is 0.1-6 mol / L normally, it is preferable that it is 0.2-5 mol / L, and it is more preferable that it is 0.3-4 mol / L.
The temperature of the electrolytic solution can usually be appropriately set at 10 to 70 ° C, but is preferably 15 to 60 ° C, and more preferably 20 to 60 ° C.
The electric conductivity of the electrolytic solution is usually 30 to 400 mS / cm, preferably 40 to 300 mS / cm, and more preferably 50 to 200 mS / cm.
Current density is usually 0.1~300A / dm ^2, is preferably from 0.3~250A / dm ^2, and more preferably 0.5~200A / dm ^2.
The voltage is usually 3 to 500 V, but a suitable range can be appropriately selected according to the type of the electrolytic solution. For example, it is preferably 10 to 30 V for a sulfuric acid aqueous solution, preferably 150 to 210 V for a phosphoric acid aqueous solution, preferably 30 to 60 V for an oxalic acid aqueous solution, and 230 to 250 V for a citric acid aqueous solution. In the case of malonic acid aqueous solution, it is preferably 100 to 140V, and in the case of tartaric acid aqueous solution, it is preferably 180 to 210V.
Among these, constant voltage electrolysis in which an anodic oxide film having a thickness of 20 μm or more is formed by using direct current and making the voltage constant is preferable in that high regularity can be obtained.
The treatment time is preferably 0.1 to 20 hours, more preferably 0.3 to 16 hours, and further preferably 0.5 to 7 hours.

In order to obtain an aluminum surface having dents that are regularly arranged, a film removal treatment for removing the anodized film formed by the self-ordering treatment is performed. In the anodized film formed by self-ordering treatment, the regularity of the micropores increases as the distance from the surface (closer to the aluminum substrate) increases. The bottom part is exposed on the surface, and in the main anodizing process to be described later, a regular depression serving as a starting point of the micropore is obtained.
Therefore, the film removal treatment is not particularly limited as long as it is a method of removing only the anodized film that is aluminum oxide without removing aluminum. Specific examples include chemical dissolution treatment and reverse electrolysis treatment.

Examples of the chemical dissolution treatment include a treatment of dissolving the anodized film using a solvent that does not dissolve aluminum but dissolves only the anodized film that is aluminum oxide.
For example, nitric acid, phosphoric acid, chromic anhydride, chromium hydroxide, zirconium phosphate compound, titanium phosphate compound, lithium salt compound, cerium salt compound, magnesium salt compound, sodium silicofluoride, zinc fluoride, manganese compound, The method of using the aqueous solution containing the at least 1 sort (s) of compound chosen from the group which consists of a molybdenum compound, a magnesium compound, and a halogen compound is mentioned. Among these, a mixed aqueous solution of chromic acid and phosphoric acid, a mixed aqueous solution of phosphoric acid and nitric acid, and a mixed aqueous solution of phosphoric acid and chromic anhydride are preferable.
The concentration of the compound contained in these aqueous solutions is preferably 0.01 to 10 mol / L, more preferably 0.05 to 5 mol / L, and further preferably 0.1 to 1 mol / L. preferable.
The temperature of the aqueous solution is preferably 0 ° C. or higher, more preferably 20 ° C. or higher, and still more preferably 40 ° C. or higher. In addition, since the starting point of ordering will be destroyed and disorder | damage | disturbed if the boiled aqueous solution is used, it is preferable to use the aqueous solution without boiling.
The treatment time is preferably 30 minutes or longer, more preferably 1 hour or longer, and even more preferably 3 hours or longer.

  The reverse electrolysis treatment is a method of obtaining an aluminum member having regular depressions as starting points of micropores by separating the anodized film and the aluminum substrate by electrolysis in an acid aqueous solution using the aluminum substrate as a cathode. is there. In this reverse electrolysis treatment, electrolysis is performed using the aluminum substrate as a cathode. This is called reverse electrolysis treatment because the electrolysis of the anodizing treatment is opposite to that of the aluminum substrate as the anode.

  In the reverse electrolysis treatment, hydrogen is generated at the interface between the anodized film and the aluminum substrate, and this hydrogen reduces the barrier layer at the interface with the aluminum substrate of the anodized film to form aluminum ions that are used as the electrolyte. It is considered that the anodic oxide film and the aluminum substrate are separated at the interface because the anodic oxide film floats from the substrate due to movement and elution into the aqueous acid solution and at the same time by the pressure of hydrogen gas.

  In the reverse electrolysis treatment, the aluminum substrate having the above-described anodized film is used as the cathode, and electricity is applied from the aluminum substrate side. The anode is not particularly limited, and examples thereof include a Pt-plated Ti electrode, a Pt electrode, and a carbon electrode. Of these, Pt-plated Ti electrodes and Pt electrodes are preferable.

The acid aqueous solution used for the reverse electrolysis treatment preferably has a pH of 1 to 7, more preferably a pH of 2 to 6, and further preferably a pH of 2.5 to 5.5. Moreover, it is preferable that it is 0.01-100 mS / cm, and, as for the electrical conductivity of acid aqueous solution, it is more preferable that it is 0.1-50 mS / cm. When the pH and electrical conductivity of the acid aqueous solution are within the above ranges, corrosion and residual film of the aluminum substrate are difficult to occur, and the peelability is improved.
If the electric conductivity of the acid aqueous solution is too low, a minimum current value may not be generated. In that case, it is preferable to increase the ion concentration in the acid aqueous solution to generate a minimum current value. On the contrary, if the ion concentration in the acid aqueous solution is too high, a minimum value of the current value is generated, but it is completed in a short time, and then the current value rapidly increases, so that control becomes difficult. Furthermore, if the time to reach the minimum value is exceeded, corrosion will occur.

In the acid aqueous solution, for example, oxalic acid, sulfuric acid, and phosphoric acid can be suitably used as the acid. Further, for example, a metal salt compound that shows acidity when dissolved in water, or an organic compound that shows acidity when dissolved in water can be used.
Examples of the metal salt compound that dissolves in water and exhibits acidity include aluminum oxalate, aluminum sulfate, aluminum lactate, aluminum fluoride, and aluminum borate.
The organic compound that is acidic when dissolved in water is preferably a carboxylic acid. For example, saturated aliphatic dicarboxylic acids such as adipic acid, unsaturated aliphatic dicarboxylic acids such as maleic acid, aromatic monocarboxylic acids such as benzoic acid, aromatic dicarboxylic acids such as phthalic acid, and aromatic oxycarboxylic acids such as salicylic acid Are preferable.
In addition, a salt that is neutral when dissolved in water, that is, a neutral salt, can also be used. Suitable examples of the neutral salt include carbonates such as ammonium carbonate and borates such as ammonium borate.
In the case where a neutral salt is used, it is also a preferred embodiment to use a mixed bath to which a fluoride, a carbonic acid derivative or an acid amide is added as an additive. Examples of the fluoride include ammonium fluoride. Examples of the carbonic acid derivative include guanidine carbonate, urea, and formaldehyde. Examples of the acid amide include acetamide.
Among these, oxalic acid, aluminum oxalate, sulfuric acid, aluminum sulfate or a mixture thereof is preferable. In particular, aluminum sulfate and sulfuric acid are preferable in terms of availability and waste liquid treatment.

  Moreover, it is one of the preferable aspects to use the same kind as the electrolyte solution used by the said anodizing process. Thereby, it becomes possible to perform anodizing treatment and reverse electrolysis in the same electrolytic cell. Moreover, even if it is a case where it carries out by another electrolytic cell, there is no bad influence by carrying in of the liquid to a reverse electrolytic cell.

The reverse electrolysis conditions vary depending on the electrolyte used, and therefore cannot be determined unconditionally.
For example, the concentration of the electrolytic solution is preferably 0.4 to 10% by mass in the case of an oxalic acid aqueous solution, 2 to 20% by mass in the case of an aqueous sulfuric acid solution, and 0.4 to 5% by mass in the case of an aqueous phosphoric acid solution. .
In general, the temperature of the electrolytic solution is preferably 0 to 50 ° C, and more preferably 10 to 35 ° C.
Current density is preferably 0.1~200A / dm ^2, more preferably from 0.3~50A / dm ^2, and even more preferably 0.5~10A / dm ^2. When it is within the above range, unevenness does not occur in peeling, and it can be performed more uniformly.
The voltage is preferably 5 to 500V, and more preferably 10 to 240V. When reverse electrolysis is performed subsequent to the anodizing treatment, it is preferable to perform constant voltage reverse electrolysis at the same voltage as the anodizing treatment.
Also, a method of repeatedly turning on and off the current intermittently while keeping the DC voltage constant, and a method of repeatedly turning on and off the current while intermittently changing the DC voltage can be suitably used. In the method of changing the voltage intermittently, it is one of preferred embodiments that the voltage is lowered sequentially. The electrolysis time is preferably 1 to 500 seconds, and more preferably 10 to 120 seconds.

  The above range is preferable because it is more excellent in the peelability between the barrier layer of the anodized film and the aluminum substrate, and the regularity of the depressions in the anodized film becomes higher. If the amount of electricity is too large or the electrolysis time is too long, the interface between the barrier layer of the anodized film and the aluminum substrate becomes high temperature, the resulting structure may be deformed, and the regularity of the dents may be impaired.

  The reverse electrolysis treatment is preferably terminated by monitoring the current value and stopping it within a range of about ± 30% around the time when the current value is minimized, and the electrolysis is performed at the point where the current value is near the minimum. More preferably, it stops and ends. In this case, the peelability and the surface properties of the anodized film and the aluminum substrate after peeling are excellent.

In the aluminum substrate obtained by performing the reverse electrolysis treatment, a residue of an anodic oxide film having a thickness of 0.2 μm or less may remain in a region of 10% or less of the peeling surface. When this aluminum substrate is used, it is preferable that no anodized film remains.
Therefore, in this case, it is preferable to remove the residue of the anodized film by performing a chemical treatment after the reverse electrolysis treatment. Specifically, it can be removed by bringing various acidic or alkaline aqueous solutions into contact with the anodized film.

Examples of the acidic aqueous solution include a phosphoric acid aqueous solution, a sulfuric acid aqueous solution, a nitric acid aqueous solution, an oxalic acid aqueous solution, and a mixed aqueous solution of chromic acid and phosphoric acid. Among these, a mixed aqueous solution of chromic acid and phosphoric acid is preferable.
The acidic aqueous solution preferably has a pH of 0.3 to 6, more preferably a pH of 0 to 4, and still more preferably a pH of 2 to 4. It is preferable that the temperature of acidic aqueous solution is 20-60 degreeC, and it is more preferable that it is 30-50 degreeC.
The treatment time is preferably 1 second to 6 hours, more preferably 5 seconds to 3 hours, and even more preferably 10 seconds to 1 hour.

Examples of the alkaline aqueous solution include aqueous solutions of sodium hydroxide, sodium carbonate, and potassium hydroxide.
The alkaline aqueous solution preferably has a pH of 10 to 13.5, more preferably a pH of 11 to 13. The temperature of the alkaline aqueous solution is preferably 10 to 50 ° C, and more preferably 20 to 40 ° C. The treatment time is preferably 1 second to 10 minutes, more preferably 2 seconds to 1 minute, and even more preferably 3 seconds to 30 seconds.

  The neutralized product produced with the alkaline aqueous solution is preferably further dissolved with the acid aqueous solution described above. As preferable acid aqueous solution, phosphoric acid aqueous solution, sulfuric acid aqueous solution, nitric acid aqueous solution is mentioned, for example. The aqueous acid solution preferably has a pH of 0.3 to 6, more preferably a pH of 0 to 4, and still more preferably a pH of 2 to 4. The temperature of the acid aqueous solution is preferably 20 to 60 ° C, and more preferably 30 to 50 ° C. The treatment time is preferably 1 second to 60 minutes, more preferably 5 seconds to 10 minutes, and even more preferably 10 seconds to 5 minutes.

Examples of suitable conditions for reverse electrolysis are illustrated below.
<Preferred condition 1>
Cathode: Anodized film obtained by anodizing with an oxalic acid aqueous solution having a concentration of 0.3 mol / L and a temperature of 17 ° C. under conditions of a voltage of 40 V and a treatment time of 60 minutes, a thickness of 60 μm, a pore diameter of 35 nm, and a pore diameter Fluctuation coefficient 15%, micropore period 63nm
Anode: Carbon electrode Electrolyte: Concentration 0.04 g / L (in terms of aluminum ion), pH 3.8, electric conductivity 0.6 mS / cm, temperature 33 ° C. Aluminum sulfate aqueous solution Voltage: 40 V (set voltage)
Current density: 5 A / dm ² (minimum value 1 A / dm ² )
Processing time: 40 seconds (minimum)

The treatment time of the reverse electrolysis treatment is extremely short compared to the time required for the film removal step of dissolving with a mixed aqueous solution of chromic acid and phosphoric acid. Further, in the mixed aqueous solution of chromic acid and phosphoric acid, when the content of aluminum oxide exceeds 15 g / L as Al ₂ O ₃ in the film removal step, the dissolving ability is rapidly deteriorated.
In contrast, in this reverse electrolysis treatment, the anodized film is released in a solid state at the interface with the aluminum substrate, so that it can be easily separated with a filter or the like, and the acid aqueous solution used for the reverse electrolysis treatment does not deteriorate. .
Therefore, the treatment time for the reverse electrolysis treatment and the consumption amount of the acid aqueous solution are much shorter and less than the treatment time for the film removal step using the mixed aqueous solution of chromic acid and phosphoric acid and the consumption amount of the treatment solution.

<Multi-stage anodizing method>
The multi-step anodizing method includes a first film dissolving process for dissolving at least a part of the anodized film on an aluminum substrate having an anodized film on the surface, and an anodizing process after the first film dissolving process. Is a method of obtaining a fine structure having micropores on the surface by performing a regularization treatment in which the process including the step is performed once or more and a second film dissolution process for dissolving the anodized film in this order.
In this case, the film thickness of the anodic oxide film before the first film dissolution treatment is preferably 10 μm or more, more preferably 15 μm or more, and further preferably 20 μm or more. Within the above range, it becomes easy to set the degree of ordering of the surface after the second film dissolution treatment to 85% or more.

<This anodizing treatment>
In the present invention, as described above, an anodized film can be formed by forming an indentation on the aluminum surface in accordance with the application and then performing an anodizing treatment. In the present specification, this anodizing treatment is referred to as “the present anodizing treatment” in distinction from the anodizing treatment used in the self-ordering method.
The anodizing treatment is not particularly limited. For example, a conventionally known method can be used, but it is preferably performed under the same conditions as the self-ordering method described above.
The film thickness of the anodized film after this anodizing treatment is preferably 0.5 to 600 μm, more preferably 10 to 400 μm, and still more preferably 20 to 200 μm. Within the above range, the catalyst performance of the catalyst body of the present invention is excellent.
Since the film thickness of the anodized film is approximately proportional to the amount of electricity, it can be adjusted by appropriately selecting the processing time and the current density.
By this anodizing treatment, a part of the valve metal is anodized to obtain an anodized film and a valve metal member that supports the anodized film.

<Pore wide processing>
The pore-wide treatment is a treatment for expanding the pore diameter of the micropores by dissolving the anodic oxide film by bringing the anodic oxide film into contact with an aqueous acid solution or an alkaline aqueous solution by a dipping method or the like after the main anodic oxidation treatment.
This makes it easy to control the regularity of the arrangement of micropores and the variation in pore diameter.

When an aqueous acid solution is used for the pore wide treatment, it is preferable to use an aqueous solution of an inorganic acid such as sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, or a mixture thereof. The concentration of the acid aqueous solution is preferably 1 to 10% by mass. The temperature of the acid aqueous solution is preferably 25 to 40 ° C.
When an alkaline aqueous solution is used for the pore-wide treatment, it is preferable to use an aqueous solution of at least one alkali selected from the group consisting of sodium hydroxide, potassium hydroxide and lithium hydroxide. The concentration of the alkaline aqueous solution is preferably 0.1 to 5% by mass. The temperature of the alkaline aqueous solution is preferably 20 to 35 ° C.
Specifically, for example, 50 g / L, 40 ° C. phosphoric acid aqueous solution, 0.5 g / L, 30 ° C. sodium hydroxide aqueous solution or 0.5 g / L, 30 ° C. potassium hydroxide aqueous solution is preferably used. .
In the case of the immersion method, the immersion time in the acid aqueous solution or alkaline aqueous solution is preferably 8 to 60 minutes, more preferably 10 to 50 minutes, and still more preferably 15 to 30 minutes.

<Surface area increase treatment>
In one preferred embodiment, the anodized film is subjected to a surface area increasing treatment for increasing the surface area.
Examples of the surface area increasing treatment include a firing treatment described in JP-A-59-059247; “New Anodized Theory”, Karos Publishing, 1997, p. Hot water hydration treatment described in 208-212; room temperature hydration treatment using room temperature hydration treatment using water containing fluoride ions, room temperature hydration treatment using pure water described in Japanese Patent No. 3154638, etc. be able to.

Of these, room temperature hydration is preferred. Although pure water can be used for the room temperature hydration treatment, the reaction accelerator is selected from the group consisting of ammonia, nickel acetate, cobalt acetate, sodium silicate, potassium dichromate and triethanolamine. It is preferable to use an aqueous solution containing at least one kind. Among these, in view of the efficiency of the hydration treatment, an aqueous solution containing at least one selected from the group consisting of ammonia, sodium silicate and triethanolamine is preferable, and an aqueous solution containing ammonia and / or sodium silicate. Is more preferable, and an aqueous ammonia solution is still more preferable.
The amount of the reaction accelerator in the aqueous solution is usually 1 to 50% by mass, preferably 3 to 40% by mass, and more preferably 5 to 30% by mass.

The temperature of the aqueous solution is preferably 5 ° C. or higher and lower than 40 ° C., more preferably 10 to 35 ° C., and still more preferably 20 to 30 ° C.
The aqueous solution preferably has a pH of 8 to 12, more preferably a pH of 10 to 12, and still more preferably a pH of 11 to 12.
When the condition of the hydration treatment is within the above range, it is possible to increase the surface area by forming a fine uneven structure inside the micropore, and to prevent the opening of the micropore from being blocked. It is preferable in that it can be performed.

<Metal with catalytic activity>
The metal having catalytic activity used in the present invention is not particularly limited, and examples thereof include known metals, alloys and metal compounds having catalytic activity.
Specifically, examples of the metal include Pt, Pd, Ru, Re, Rh, Ni, Mo, Ru, Cu, Co, Au, and Ag. Examples of the alloy include alloys of these metals, and more specifically, for example, Pt—Rh—Pd ternary catalyst and Re—Pt alloy. Examples of the metal compound include salts and complexes of these metals or alloys.
Among them, precious metal catalysts that are widely used are preferable because they are easily handled in a fine particle state and have high catalytic activity.
In particular, at least one metal selected from the group consisting of Pt, Pd, Au, Ag, Re, and Rh, or a salt or complex thereof is preferable, and Pt or a Pt alloy, or a salt or complex thereof is preferable.

<Catalyst loading treatment>
The catalyst body of the present invention can be obtained by supporting the above-mentioned metal having catalytic activity in the micropores of the anodized film.
Specifically, a metal having catalytic activity is adsorbed on the anodized film, and is further immobilized so that it does not desorb even when it comes into contact with a substance (for example, fluid) used in the catalytic reaction.
The method for the catalyst supporting treatment is not particularly limited, and for example, a known method such as a soaking method, an ion exchange method, a coprecipitation method, a deposition method, a kneading method, a hydrothermal synthesis method, a gas phase synthesis method, or the like may be used. it can. Among these, the impregnation method is preferable.
The impregnation method is classified according to the process, and an adsorption method, a pore filling method, an incipient wetness method, an evaporation to dryness method, a spray method and the like are known.
Among them, the Catalyst Society, “Catalyst Experiment Handbook”, Kodansha, 1989, p. A method of immersing in an aqueous solution containing a metal ion having catalytic activity as described in 18-34 is preferred, and a method of immersing in an aqueous solution containing a noble metal ion having catalytic activity is more preferred.
In this case, the temperature of the aqueous solution is preferably 5 to 80 ° C, more preferably 10 to 50 ° C, and still more preferably 5 to 40 ° C. The aqueous solution preferably has a pH of 7.5 to 13, more preferably a pH of 8 to 12, and still more preferably a pH of 9 to 12. The treatment time is preferably from 0.1 to 12 hours, more preferably from 0.5 to 10 hours, and even more preferably from 1 to 8 hours.

  Aqueous solutions used for the impregnation method include chlorides, bromides, ammonium compounds, cyanides, alkali metal salts (that is, salts with alkali metals such as K and Na), and complex compounds thereof, containing metals having catalytic activity. Can be prepared. Of these, chlorides and ammonium compounds are preferred from the standpoint of availability and ease of preparation.

<Simultaneous processing>
When ammonia is added to an aqueous solution (acidic) of hexachloroplatinic (IV) acid / hexahydrate or an aqueous solution (acidic) of dichlorotetraammineplatinum (II) / n-hydrate to adjust the pH to an alkaline pH of 8 to 13, Platinum ions react with ammonia to form complex ions, forming [Pt (NH ₃ ) ₄ ] ²⁺ complexes.
When the catalyst supporting treatment is performed using this aqueous solution, fine crystals are formed, and it is expected to show high performance as a catalyst body, and the surface area increasing treatment by hydration treatment is performed simultaneously with the catalyst supporting treatment. It is preferable in terms of efficiency.

<Baking treatment>
In the present invention, for the purpose of increasing the surface area of the catalyst body of the present invention on the anodic oxide film side or fixing the catalytically active metal adsorbed on the anodic oxide film, a firing treatment is further performed. Can do.
The calcination treatment is preferably performed by holding at 100 to 600 ° C. for 0.1 to 5 hours in air or an inert gas atmosphere, and at 350 to 600 ° C. for 0.5 to 3 hours in an inert gas atmosphere. More preferably, it is carried out by holding.

<Valve metal member removal treatment>
In particular, when the catalyst body of the present invention is used in a high temperature environment, it may be preferable to use the catalyst body in a mode in which the valve metal member is removed. For this reason, the process which removes a valve metal member can be performed before or after a catalyst carrying process.
The method for removing the valve metal member is not particularly limited. For example, a solvent that is hardly soluble or insoluble for the anodizing treatment and soluble for the valve metal is used, and preferably 0 to 80. C., more preferably 10 to 60.degree. C., more preferably 20 to 40.degree. C., preferably 10 minutes or more, more preferably 30 minutes or more, still more preferably 1 hour or more. The method of making it contact with an anodized film depending on the case is mentioned.
When aluminum is used as the valve metal, the solvent is halogen such as bromine or iodine; acidic solvent such as dilute sulfuric acid, phosphoric acid, oxalic acid, sulfamic acid, benzenesulfonic acid, amidosulfonic acid; sodium hydroxide, hydroxide Alkaline solvents such as potassium and calcium hydroxide are preferred, and bromine and iodine are more preferred.
The method for bringing the valve metal member into contact with the solvent is not particularly limited, and examples thereof include a dipping method and a dropping method.
Moreover, the reverse electrolysis process mentioned above is also suitably used as a process method for removing the valve metal member.

<Penetration processing>
The catalyst body of the present invention may have a form in which the bottom of the micropore is penetrated and both ends of the micropore are open. In this embodiment, when a fluid such as a gas or a liquid is used for the catalytic reaction, the reaction can be performed in a state in which the fluid is circulated through the micropore, so that the catalyst efficiency is excellent.
The penetration treatment can be performed by performing the above-described valve metal removal treatment as necessary, followed by chemical dissolution treatment, ion milling treatment, and the like. In this, the bottom of the micropore penetrates, A catalyst body having a shape in which is opened is obtained.

The chemical dissolution treatment is a method of dissolving the anodized film using an aqueous solution capable of dissolving the anodized film (for example, an electrolytic solution for anodizing treatment used in the above-described self-ordering method).
As the aqueous solution, acidic aqueous solutions such as sulfuric acid, oxalic acid, phosphoric acid and malonic acid are preferable. The concentration of the aqueous solution is usually 0.1 to 6 mol / L, preferably 0.2 to 5 mol / L, and more preferably 0.3 to 4 mol / L. The temperature of the aqueous solution is usually 10 to 70 ° C, preferably 15 to 60 ° C, and more preferably 20 to 60 ° C.
The method of chemical dissolution treatment is not particularly limited. For example, an anodic oxide film obtained by removing the valve metal is put in a vacuum filter holder so that the barrier layer side is in contact with the aqueous solution, and the aqueous solution is put from above. It can be performed by setting in a suction filtration bottle and sucking. In this method, when the bottom of the micropore penetrates and the aqueous solution penetrates and drops, the suction is stopped, and the aqueous solution is replaced with neutral water and washed with water. Thereafter, it is naturally dried to obtain a membrane filter-like penetrating membrane.

  The ion milling process is a method in which an argon ion beam or the like accelerated at 2 to 10 kV is irradiated to the valve metal at an incident angle of 10 ° or less, and the barrier layer is shaved to penetrate the bottom of the micropore. The ion milling treatment can be performed using a commercially available apparatus such as a PIPS precision ion polishing apparatus 691 type, a precision etching coating system 682 type PECS and an ion milling apparatus E-3500 manufactured by Hitachi High-Technology Corporation.

<Surface area ratio>
In the catalyst body of the present invention, the surface area ratio obtained by dividing the actual surface area measured by the BET method after being held at 200 ° C. for 2 hours on the surface on the anodized film side by the geometric surface area is 5000-30. Ten thousand.
The actual surface area is measured by the BET method after being held at 200 ° C. for 2 hours. By holding the catalyst body at 200 ° C. for 2 hours, the actual surface area measured in the subsequent BET method becomes a stable value.
As a method for holding the catalyst body at 200 ° C. for 2 hours, for example, a method of heating in a vacuum, a method of heating in an inert flow gas after storing in a vacuum, and the like are preferable.

The BET method is a method in which a substance having a known adsorption occupation area is adsorbed on a sample surface at the temperature of liquid nitrogen, and the surface area of the sample is obtained from the amount.
In the present invention, the BET method can be performed by a conventional method. For example, the Catalysis Society of Japan, “Catalyst Experiment Handbook”, Kodansha, 1989, p. This can be done with reference to the description of 167-168.
The measuring instrument used for BET method is not specifically limited, For example, a commercially available measuring instrument is mentioned. Specifically, for example, Flowsorb manufactured by Shimadzu Corporation and Autosorb manufactured by Cantachrome are listed.
As the adsorbate, organic compounds such as nitrogen, krypton, benzene and toluene are used. Of these, nitrogen and a mixed gas of nitrogen and helium are generally used. When the actual surface area of the catalyst body is relatively small, krypton gas is preferably used.
The adsorption time in the BET method varies depending on the actual surface area of the catalyst body, the amount of the catalyst body to be measured, and the like, but is approximately in the range of 30 minutes to 15 hours for a size of 25 mm × 2 mm, for example. Desorption time is about 5 to 10 minutes.
As the actual surface area, an area value measured at the time of desorption is used.

  The geometric surface area is an area calculated on the assumption that the surface of the catalyst body on the anodized film side is a plane. Specifically, it is calculated from the size of the catalyst body measured with calipers or the like.

  The surface area ratio is calculated by dividing the actual surface area obtained as described above by the geometric surface area.

  The catalyst body of the present invention has a surface area ratio of 5000 to 300,000, preferably 10,000 to 250,000, and more preferably 20,000 to 200,000. Within the above range, the balance between the catalyst performance (for example, dehydrogenation reaction of methylcyclohexane), the catalyst performance such as the conversion rate, and the simplicity of catalyst body preparation is excellent.

<Straight pipe degree>
In the catalyst body of the present invention, 10% or more, preferably 15% or more, more preferably 20% or more of the micropores present on the surface on the anodized film side are straight tubular micropores.
In general, in order to increase the efficiency of the catalytic reaction, it is necessary to increase the surface area ratio of the catalyst body. For example, the surface area ratio can be increased by increasing the thickness of the anodized film and deepening the micropores. If it is increased, fluids such as liquid and gas used for the catalytic reaction will not easily reach the deep part of the micropore, and the efficiency of the catalytic reaction will not be increased.
On the other hand, in a straight tubular micropore, a fluid such as a liquid or gas used for a catalytic reaction can smoothly move to a deep portion of the micropore. Therefore, it is preferable that the ratio of the straight tubular micropores (straight tube degree) is in the above range because the efficiency of the catalytic reaction is increased even when the micropores are deepened.

The straightness of the pores can be obtained by observing the cross section of the catalyst body with an SEM or the like, and assuming that there is no branching or blockage as a straight tubular shape and calculating the proportion of such micropores. The straight tubular pore may be bent as long as there is no branching or blocking.
The straightness of the pore is, for example, by bending the catalyst body to produce a fractured surface of the anodized film, observing with FE-SEM, and taking a total of five photographs from the middle to the bottom of the micropore at a magnification of 50,000 times And calculated from the following formula (1) from the number C of micropores that are straight tubular in the field of view and the number D of micropores that are branched or closed.

  Straightness (%) = C / (C + D) × 100 (1)

  In the present invention, in the surface area increasing process and the catalyst supporting process, it is difficult to observe the vicinity of the surface of the anodized film, so the observation with SEM or the like is performed in the range from the middle part to the bottom part of the micropore. Is preferred.

FIG. 1 is an example of a cross-sectional SEM photograph of the catalyst body of the present invention (photographing magnification of 50,000 times, lower left bar length of 0.2 μm). The catalyst body shown in FIG. 1 has an anodized film having micropores in the upper part of FIG. In the catalyst body shown in FIG. 1, the straight pipe degree is 100%.
FIG. 2 is an explanatory diagram of a method for calculating the straight pipe degree of the pore. In FIG. 2A, none of the four micropores 10 is branched or blocked. Therefore, the ratio of straight tubular micropores is 4/4 × 100 = 100 (%). On the other hand, in FIG. 2B, among the six micropores, there are four branched micropores 12 and one micropore 14 closed at the middle of the other micropores. There is one tubular micropore 10. Therefore, the straight pipe degree is 1/6 × 100 = 17 (%).

<Regularity>
In the catalyst body of the present invention, the degree of order of micropores in the anodized film is preferably 10% or more, more preferably 20% or more, and further preferably 30% or more.
The degree of ordering is an index of the regularity of the micropore. The bottom of the micropore is penetrated by the above-described valve metal member removing process and the subsequent penetrating process, and a photograph by FE-SEM is taken from the back side. Calculate by (2).

  Ordering degree (%) = B / A × 100 (2)

  In the above formula (2), A represents the total number of micropores in the measurement range. B is centered on the center of gravity of one micropore, and when a circle with the shortest radius inscribed in the edge of another micropore is drawn, the center of gravity of the micropore other than the one micropore is placed inside the circle. This represents the number in the measurement range of the one micropore to be included.

FIG. 3 is an explanatory diagram of a method for calculating the degree of ordering of pores. The above formula (1) will be described more specifically with reference to FIG.
The micropore 1 shown in FIG. 3 (A) draws a circle 3 (inscribed in the micropore 2) having the shortest radius that is centered on the center of gravity of the micropore 1 and inscribed in the edge of another micropore. In this case, the center of the circle 3 includes six centroids of micropores other than the micropore 1. Therefore, the micropore 1 is included in B.
The micropore 4 shown in FIG. 3B draws a circle 6 (inscribed in the micropore 5) having the shortest radius that is centered on the center of gravity of the micropore 4 and inscribed in the edge of another micropore. In this case, the center of gravity of the micropores other than the micropores 4 is included inside the circle 6. Therefore, the micropore 4 is not included in B. In addition, the micropore 7 shown in FIG. 3C is centered on the center of gravity of the micropore 7 and has the shortest radius 9 inscribed in the edge of another micropore (inscribed in the micropore 8). Is drawn, the circle 9 includes seven centroids of micropores other than the micropore 7. Therefore, the micropore 7 is not included in B.

  The catalyst body of the present invention can be used for various applications depending on the type of catalyst used.

The present invention will be specifically described below with reference to examples. However, the present invention is not limited to these.
1. Preparation of catalyst bodies (Examples 1 to 19 and Comparative Examples 1 and 2)
As shown in Table 1, the substrate was sequentially subjected to degreasing treatment, starting point formation treatment (Example 1 only), main anodizing treatment, pore wide treatment, catalyst support treatment and reverse electrolysis treatment (Example 19 only). Each catalyst body was obtained.

  Hereinafter, the substrate and each process will be described.

(1) Substrate The substrates used for manufacturing the structure are as follows. These were cut into a size that can be anodized in a 10 cm square range.
Substrate 1: JIS 1N99 material, manufactured by Nippon Light Metal Co., Ltd., purity 99.99 mass%, thickness 0.30 mm
Substrate 2: JIS 1090 material, manufactured by Uniface Aluminum, purity 99.9% by mass, thickness 0.30 mm
Substrate 3: JIS 1070 material, manufactured by Unifas Aluminum, purity 99.7% by mass, thickness 0.30 mm
Substrate 4: JIS 1050 material, manufactured by Nippon Light Metal Co., Ltd., purity 99.5% by mass, thickness 0.24 mm
Substrate 5: JIS 1N30 material, manufactured by Unifas Aluminum, purity 99.3 mass%, thickness 0.30 mm
Substrate 6: JIS 1100 material, manufactured by Unifas Aluminum, purity 99% by mass, thickness 0.30 mm
Substrate 7: JIS 1050 material, manufactured by Nippon Light Metal Co., Ltd., purity 99.5% by mass, thickness 3 mm

(2) Degreasing treatment In order to remove the rolling oil, the sponge (PS sponge, Fuji Photo Film Co., Ltd.) was immersed in a water-diluted solution (concentration 10% by mass, temperature 40 ° C.) of a neutral detergent (Charmy, Lion). )) For 10 minutes.

(3) Starting point formation process In Example 1, as shown below, the starting point formation process which forms the hollow used as the starting point (starting point) of formation of a micropore was performed. In Examples 2 to 17 and Comparative Examples 1 and 2, the starting point forming process was not performed.

  Specifically, in the starting point forming process, the following first anodizing process, first chemical dissolving process, second anodizing process, and second chemical dissolving process are performed on the substrate 1 in this order. It went by.

<First anodizing treatment>
The first anodic oxidation treatment is performed by using an oxalic acid aqueous solution having a concentration of 0.5 mol / L and a temperature of 16 ° C. as an electrolytic bath, and performing the electrolytic treatment for 60 minutes in a constant voltage condition of a voltage of 40 V in the electrolytic bath. An anodized film having a thickness of 9 μm was formed. Although the current density was not particularly controlled, the average value during the anodizing treatment was about 0.5 A / dm ² .

<1st chemical dissolution treatment>
The first chemical dissolution treatment was performed by immersing in an aqueous phosphoric acid solution having a concentration of 0.56 mol / L and a temperature of 40 ° C. for 20 minutes to dissolve the anodized film to a thickness of 8 μm.

<Second anodizing treatment>
The second anodic oxidation treatment is performed by using an oxalic acid aqueous solution having a concentration of 0.5 mol / L and a temperature of 16 ° C. as the electrolytic bath, and performing the electrolytic treatment for 60 minutes in a constant voltage condition of a voltage of 40 V in the electrolytic bath. The anodized film was grown to a thickness of 17 μm. Although the current density was not particularly controlled, the average value during the anodizing treatment was about 0.5 A / dm ² .

<2nd chemical dissolution treatment>
The second chemical dissolution treatment was performed by immersing in an aqueous phosphoric acid solution having a concentration of 0.56 mol / L and a temperature of 40 ° C. for 20 minutes to dissolve the anodized film to a film thickness of 8 μm.

(4) The present anodizing treatment In Examples 1 to 19, the present anodizing treatment by the constant voltage electrolytic treatment was performed with the type, concentration and concentration, voltage, current density and treatment time of the electrolytic solution shown in Table 1. An anodized film having a film thickness shown in Table 1 was formed. In Table 1, the current density was not particularly controlled, but an average value during the anodizing treatment was shown.
In Example 1, an FE-SEM photograph (magnification of 50,000 times) was taken for the obtained anodic oxide film, 20 micropores were appropriately selected from the photograph, and the pore diameter was measured with calipers. The standard deviation was 33 nm and 3 nm.

In Comparative Examples 1 and 2, the main anodic oxidation treatment by constant current electrolytic treatment was performed with the type, concentration and concentration, voltage, current density and treatment time of the electrolytic solution shown in Table 1, and shown in Table 1. An anodic oxide film having a film thickness was formed. The voltage was not particularly controlled, but was 60 V at the start of the anodizing treatment and 35 V at the end, and gradually decreased during that time.
In this anodizing treatment, NeoCool BD36 (manufactured by Yamato Scientific Co., Ltd.) was used as a cooling device, Pear Stirrer PS-100 (manufactured by EYELA) as a stirring and heating device, and GP0650-2R (manufactured by Takasago Seisakusho) as a power source.
In Table 1, for oxalic acid and sulfuric acid, reagents manufactured by Kanto Chemical Co., Inc. were used.

(5) Pore-wide treatment The pore-wide treatment was performed by immersing the substrate in an aqueous phosphoric acid solution having a concentration of 5 mass% and a temperature of 30 ° C for 15 minutes.
In Example 1, an FE-SEM photograph (magnification of 50,000 times) was taken for the anodized film after the pore-wide treatment, 20 micropores were appropriately selected from the photograph, and the pore diameter was measured with calipers. The diameter was 40 nm.

(6) Catalyst support treatment HPtCl ₆ .6H ₂ O (a reagent manufactured by Kanto Chemical Co., Inc.) was dissolved in pure water so that the Pt content was about 2 g / L. Next, ammonia water (a reagent manufactured by Kanto Chemical Co., Inc.) was added to adjust to pH 11.4, and then pure water was added to finally adjust the Pt content to 1 g / L.
The obtained aqueous solution was stirred at room temperature for 6 hours, and after confirming that the color of the aqueous solution changed from the original yellow color to a nearly transparent and colorless state and was stable, the program low temperature incubator (IQ820, manufactured by Yamato Scientific Co., Ltd.) was in progress. The plastic bottle containing the aqueous solution was placed in a sealed state at 25 ° C., and then the substrate was immersed for the time shown in Table 1 to carry out the catalyst loading treatment to obtain a catalyst body.

(7) Reverse electrolysis treatment In Example 19, reverse electrolysis treatment was performed as follows to separate the anodized film from the substrate. In Examples 1 to 18 and Comparative Examples 1 and 2, no reverse electrolysis treatment was performed.
In the reverse electrolysis treatment, after masking, the substrate after the catalyst supporting treatment is used as a cathode, a Pt electrode is used as an anode, and an aluminum sulfate aqueous solution having a concentration of 4.5 g / L and a temperature of 33 ° C. is set at a constant voltage of 16V. It applied by performing an electrolytic process on voltage conditions, and, thereby, the anodized film and the board | substrate were peeled.
In the reverse electrolysis treatment, the current value was monitored, and the reverse electrolysis treatment was terminated when the current value became 10% or less of the initial current value.
In the reverse electrolysis on the surface of the anodic oxide film, the anodized film was separated from the substrate by cutting with a cutter at the boundary (circular shape with a radius of 1.7 cm) between the part in contact with the electrolytic solution and the part not in contact with the electrolytic solution.
In addition, the penetration process was not performed after the reverse electrolysis process.

2. Properties of catalyst body (1) Surface area ratio The catalyst body obtained above was cut into a size of 40 mm x 3 mm by a small cutting machine. The cut catalyst body was put in a commercially available vacuum storage container and stored at a vacuum degree of 1 × 10 ⁻¹ Pa for 12 hours.
Subsequently, the catalyst body was put into a flow type specific surface area automatic measuring device (Flowsorb III 2305, manufactured by Shimadzu Corporation), and kept at 200 ° C. for 2 hours under a nitrogen gas flow containing 0.1% krypton, and deaerated.
Thereafter, when the short pass was used as the sensitivity setting 1/1, and adsorption was performed at a liquid nitrogen temperature for 1 hour under the flow of nitrogen gas containing 0.1% krypton, the signal disappeared and the adsorption was completed. Subsequently, when the temperature was returned to room temperature, the signal disappeared after 5 minutes and the desorption was completed.
The actual surface area obtained from the desorption data was divided by the geometric area (0.00012 m ² ) to calculate the surface area ratio. The results are shown in Table 1.

(2) Straight pipe degree The catalyst body obtained above is bent, a fracture surface of the anodized film is prepared, observed by FE-SEM (S-900, manufactured by Hitachi, Ltd.), and from the middle part of the micropore A total of five photographs were taken at a magnification of 50,000 times from the bottom. From the number C of straight micropores in the field of view and the number D of branched or closed micropores, The straight pipe degree was calculated by equation (1). The results are shown in Table 1.

(3) Degree of ordering The catalyst body obtained above was subjected to reverse electrolysis treatment, and the anodized film was peeled off from the substrate. The conditions for the reverse electrolysis treatment were as follows.
Cathode: catalyst body obtained above Anode: Carbon electrode Electrolyte: Concentration 0.04 g / L (in terms of aluminum ion), pH 3.8, electric conductivity 0.6 mS / cm, temperature 33 ° C. Aluminum sulfate aqueous solution Voltage: 40V (set voltage)
Current density: 5 A / dm ² (minimum value 1 A / dm ² )
Processing time: 40 seconds (minimum)

  Subsequently, the obtained anodic oxide film was subjected to penetration treatment. The penetration treatment is performed by floating the anodized film in a phosphoric acid aqueous solution having a concentration of 5% by mass and a temperature of 40 ° C. with the barrier layer side facing down, and leaving it for 30 minutes, thereby dissolving the barrier layer, The bottom of the micropore was penetrated.

  For the anodized film through which the bottom of the micropore penetrates, a photograph (magnification of 50,000 times) is taken from the back side by FE-SEM, and the micropore is defined by the above formula (2) in the field of view of 1.2 μm × 2 μm. The degree of ordering was measured. The degree of ordering was measured at 150 locations, and the average value was calculated. The results are shown in Table 1.

3. Performance Evaluation of Catalyst Body Using a flow-type differential reaction apparatus (shown in FIG. 1 of Chemical Engineering Papers, Vol. 19, No. 1 (1993), p. 42), methyl is obtained as follows. The dehydrogenation reaction of cyclohexane was performed, the dehydrogenation reaction rate of the catalyst body was measured, and the performance evaluation of the catalyst body was performed.
As pretreatment, air oxidation was performed at 350 ° C. for 12 hours, followed by reduction with hydrogen for 2 hours, and then the temperature was lowered to 200 ° C. while purging with nitrogen.
Next, methylcyclohexane at 5 ° C. was vaporized by bubbling and brought into contact with nitrogen gas used as a carrier gas, and the gas concentration of methylcyclohexane was controlled by appropriately controlling the temperature and the degree of bubbling. The introduction concentration was 200 ppm. The reaction pressure was 1 atmosphere.
After contacting methylcyclohexane with the catalyst body for 1 hour, the generated toluene concentration was determined by a calibration curve method. The dehydrogenation reaction rate was calculated from the generated toluene concentration by the following formula. The results are shown in Table 1.

  Dehydrogenation reaction rate (%) = (generated toluene concentration) / (introduced methylcyclohexane concentration = 200 ppm) × 100

  As is apparent from Table 1, the catalyst bodies of the present invention (Examples 1 to 19) had a higher dehydrogenation reaction rate than the cases where the straightness was low (Comparative Examples 1 and 2).

It is an example of the cross-sectional SEM photograph of the catalyst body of this invention. It is explanatory drawing of the method of calculating the straight pipe degree of a pore. It is explanatory drawing of the method of calculating the regularization degree of a pore.

Explanation of symbols

1, 2, 4, 5, 7, 8 Micropore 3, 6, 9 yen 10 Straight tubular micropore 12 Branched micropore 14 Closed micropore

Claims (3)

A catalyst body having an anodized film having micropores obtained by subjecting a valve metal to anodization, and a metal having catalytic activity present in the micropores,
About the surface on the anodized film side, the surface area ratio obtained by dividing the actual surface area measured by the BET method after holding at 200 ° C. for 2 hours by the geometric surface area is 5000 to 300,000,
A catalyst body in which 10% or more of the micropores existing on the surface on the anodic oxide film side are straight tubular micropores.   The catalyst body according to claim 1, further comprising a valve metal member that supports the anodized film.   The catalyst body according to claim 1 or 2, wherein the valve metal is aluminum.