JP6334161B2 - Hydrogen catalyst material - Google Patents

Description

  The present invention relates to a hydrogen catalyst member.

  In recent years, an organic hydride system using hydrocarbons such as cyclohexane and decalin has attracted attention as a hydrogen storage method excellent in safety, transportability and storage capacity. Since these hydrocarbons are liquid at room temperature, they are excellent in transportability.

  For example, benzene and cyclohexane are cyclic hydrocarbons having the same carbon number, but benzene is an unsaturated hydrocarbon in which the bonds between carbons are double bonds, whereas cyclohexane is a saturated hydrocarbon having no double bonds. Hydrogen. Therefore, when a hydrogen catalyst member is used, cyclohexane is obtained by the hydrogenation reaction of benzene, and benzene is obtained by the dehydrogenation reaction of cyclohexane. That is, hydrogen can be stored and supplied by utilizing hydrogenation and dehydrogenation of these hydrocarbons.

By the way, in Patent Document 1, when energized, a surface of an aluminum foil is made into a porous oxide film by anodic oxidation, and a hydrogen catalyst member carrying a metal catalyst on the surface is intermittently formed on the surface of the foil by embossing. A method has been proposed in which a portion is provided or a flat foil is laminated on a corrugated foil and wound.

JP 2011-50925 A

  When a hydrogen catalyst member using aluminum foil is stacked or wound and sealed in a reaction tube, the foil surface area of the foil is increased by a method by etching, with a hole diameter of micron order by pitting corrosion, in order to increase the surface area of the foil. In order to further increase the surface area of the foil, a plurality of tunnel-like holes (etching pits) from both sides to the vicinity of the center are provided at intervals of a micron order. In the case where a porous oxide film is formed by anodic oxidation on the surface, the anodic oxidation is a method of oxidizing the material metal itself, and since the shape is a hole, a certain amount of depth is required. If an attempt is made to increase the etching pit, the peripheral portion of the etching pit is almost oxidized. Therefore, if the foil is deformed so as to provide a convex shape on the foil in order to provide a space between the foils, the deformation tends to cause cracks in the foil. In particular, when trying to continuously manufacture a long product, it is easy to break the foil.

The present invention is intended to solve the above-described problems, and provides a hydrogen catalyst member that does not cause a foil break even when a long product is continuously manufactured.

In order to solve the above problems, the present invention provides the following hydrogen reaction apparatus.
(1) In a hydrogen catalyst member laminated or wound using an aluminum foil carrying a metal catalyst, the hydrogen catalyst member having a convex spacer formed by deforming the foil, the aluminum foil Is a hydrogen catalyst member characterized by having etching pits due to pitting corrosion, leaving an aluminum metal portion between the etching pits, and having a feather-like γ-alumina layer on the surface thereof.
(2) In the above (1), the height of the convex shape is 200 μm to 2000 μm.

According to the present invention, when a hydrogen catalyst member using an aluminum foil is laminated or wound and sealed, in order to provide a space between the foils, it has a convex shape formed by deforming the foil, In addition, in order to increase the surface area of the foil, in the hydrogen catalyst member having etching pits, the aluminum metal portion between the etching pits is left and the surface has a feathery γ-alumina layer. Even if it tries to manufacture a long thing continuously, maintaining a high surface area, the hydrogen catalyst member which does not raise | generate a foil break easily can be provided.

The expanded schematic sectional drawing of the hydrogen catalyst member before carrying the metal catalyst of this invention is shown. It is the hydrogen catalyst member of Example 1 of this invention, and has shown the case where a flat foil is laminated | stacked and wound on a corrugated foil. It is the hydrogen catalyst member of Example 2 of this invention, and has shown the case where a flat foil is laminated | stacked and wound on a corrugated foil.

The metal catalyst described in the present invention is a metal for a hydrogen catalyst, including metals such as nickel, palladium, platinum, rhodium, iridium, rhenium, ruthenium, molybdenum, tungsten, vanadium, osmium, chromium, cobalt, iron, and alloys thereof. Can be used.
The method for supporting the metal catalyst is carried out by immersing the catalyst metal in a colloidal dispersion or by electroless plating of the metal catalyst.

The aluminum foil of the present invention is a deformable aluminum foil on which a metal catalyst is supported. The thickness of the range of the range which can be wound up in roll shape is used. For example, an aluminum foil having an industrial production of about several μm to several hundred μm and about 20 μm to 200 μm can be used.
Further, the purity is 99.2% or more, and a material added with manganese, iron, magnesium, silicon, copper, lead or the like can be used. These additives can improve the strength or etchability of the aluminum.
As the surface shape of the foil, a structure of holes (etching pits) roughened in a tunnel shape having a hole diameter of micron order by etching is provided on the foil to increase the reaction surface area.
The etching process is performed by chemical dissolution or electrochemical reaction by immersing in a solution containing chlorine such as hydrochloric acid. For the etching property, the amount of iron, copper, lead or the like is adjusted so that pitting corrosion is more likely to occur than the overall corrosion. Their addition amount is preferably about 1 ppm to 100 ppm. In addition, it is preferable that the crystal orientation is aligned by rolling, annealing, or the like because pitting corrosion extends straight into the foil.
Usually, the hole diameter of the etching pits in this case is approximately 0.2 μm to 2 μm. The length of the etching pit is 40% to 45% of the foil thickness. Further, the width of the remaining aluminum metal portion between the etching pits is preferably about 0.3 μm to 3 μm on average. More preferably, the average is about 0.4 μm to 2 μm.
When it is 0.3 μm or less, it is easy to cause a foil break when trying to continuously manufacture a long product. When it is larger than 3 μm, the number of etching pits is reduced and the reaction surface area is likely to be lowered.

The γ-alumina layer of the present invention is a film layer obtained by oxidizing the surface of an aluminum foil including the surface of etching pits, and has a shape protruding in a feather shape. The γ-alumina layer also includes a pseudo γ crystal structure.
An aluminum metal portion between the etching pits is left and provided. By leaving a large amount of the aluminum metal portion, not only the foil strength can be obtained, but also in terms of heat conduction.
The thickness of the γ-alumina layer is about 0.1 μm to 1 μm. Preferably, it is about 0.2 μm to 0.5 μm.
The γ-alumina layer is generally obtained by baking after boehmite treatment. Further, before the boehmite treatment, alumite treatment is performed by anodic oxidation with oxalic acid or the like. The surface in the etching pit is also a porous film, which increases the surface area, which is preferable in that respect. The thickness of the alumite depends on the width of the remaining aluminum between the etching pits. However, when the remaining aluminum has an average width of about 1 μm, the thickness is 0.2 μm or less.

The boehmite treatment is intended to form feathered aluminum hydroxide on the surface of the aluminum foil, and is performed in water at pH 6 to pH 8, preferably pH 7 to pH 8, and at 90 to 100 ° C. under atmospheric pressure. The higher the temperature, the thicker the time. Moreover, if a pressurized container is used and the temperature is 100 ° C. or higher, the processing time can be shortened.
The purpose of the baking treatment is to obtain a feathery γ-alumina by converting the boehmite film to γ-alumina, and is usually performed at 300 to 550 ° C. for about 0.1 to 5 hours.

  The hydrogen catalyst member of the present invention relates to an apparatus for directly decomposing lower hydrocarbons, particularly an apparatus for directly decomposing lower hydrocarbons such as methane (CH4) into carbon and hydrogen by contact with a catalyst, methanol or LPG, natural gas, etc. A hydrogen generator that generates hydrogen from a part of the hydrocarbon fuel using a reforming catalytic converter, or an organic hydride system that stores and supplies hydrogen by using hydrogen addition and dehydrogenation of hydrocarbons Can be used.

A method for obtaining a convex shape formed by deforming a foil can be used without any particular limitation, such as an extruding process using a molding roller by an embossing roll, or a corrugated process in which the entire foil is deformed. The processing for obtaining the convex shape can be performed even after the metal catalyst is supported.
The height of the concavo-convex process is such a size as to obtain the desired air permeability between the foils, and a height of 200 μm to 2000 μm is used. The height is preferably 300 μm to 1000 μm.
If it is smaller than 200 μm, the air permeability tends to be hindered. If it is larger than 2000 μm, it is difficult to reduce the size and processing becomes difficult.
The interval between the convex portions is provided so that the convex portions between the stacked layers do not overlap each other.
The method of winding is to match the reaction vessel to be inserted, such as a circular, elliptical, oval cross-section, or a circular shape obtained by crushing a circular shape into an oval shape, or in some cases a zigzag folded shape. Do it.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an enlarged schematic cross-sectional view of a hydrogen catalyst member before carrying a metal catalyst. The aluminum foil 1 is provided with a plurality of etching pits 2, which are tunnel-like holes having a hole diameter of micron order due to pitting corrosion, at intervals of micron order from both surfaces to the inside by etching. Between the etching pits 2, an aluminum metal portion is left with a width of a micron order, and is integrated with the aluminum metal portion in the central portion of the aluminum foil 1. On the surface including the etching pit 2, a porous anodized layer 3 having a thickness of submicron order is provided by anodic oxidation with oxalic acid or the like. A feather-like γ-alumina layer 4 is provided on the surface of the anodized layer 3.

FIG. 2 shows a case where the aluminum foil 1 is embossed as a convex shape formed by deforming the foil, and shows a hydrogen catalyst member in the middle of winding. By providing the convex deformation portion 5 on the aluminum foil 1 by embossing, the aluminum foils 1 are prevented from closely contacting each other by winding, and the flow of substances (hydrogen medium and hydrogen) before and after the reaction is made smooth.
When the aluminum foil 1 is wound in a coil shape, the container can be easily stored when the container cross-sectional shape is a cylinder.

  FIG. 3 shows a hydrogen catalyst member obtained by laminating and winding a flat aluminum foil 1b on a corrugated aluminum foil 1a formed by deforming the foil. The shape of the undulating process may be a undulating curve, a chevron straight line, or an intermediate point.

  Hereinafter, the method for producing a hydrogen catalyst member of the present invention will be described based on examples.

Example 1
First, a 120 μm aluminum foil is immersed in a hydrochloric acid aqueous solution and continuously etched at a liquid temperature of 80 ° C. for 6 minutes. Etching pits having an average diameter of 0.9 μm and an average depth of 52 μm are formed on both surfaces. Got in. Next, a porous oxide film layer was formed by an anodic oxidation method in an oxalic acid solution, and then the pores were enlarged. Next, after boiling in boiling water, heating was performed at 450 ° C. for 30 minutes to obtain a γ-alumina layer having a feathery surface. At this time, the width of the aluminum metal portion remaining between the etching pits was 0.5 μm on average.
Next, the treated foil was immersed in a colloidally dispersed platinum catalyst for dehydrogenation to carry the platinum catalyst.
Next, the convex-shaped deformation process which used the roller of the shaping | molding by an embossing roll continuously was performed. The convex deformation process was random with an average height of 310 μm, a diameter of 1.5 mm, and an interval of 7 mm to 12 mm. Next, in accordance with the shape of the hydrogen reaction vessel, as shown in FIG. 2, the supported foil was wound around a winding shaft to form a coil to obtain a hydrogen catalyst member.

(Example 2)
First, a 110 μm aluminum foil is immersed in an aqueous hydrochloric acid solution and continuously etched at a liquid temperature of 80 ° C. for 6 minutes. Got in. Next, after boiling in boiling water, heating was performed at 450 ° C. for 30 minutes to obtain a γ-alumina layer having a feathery surface. At this time, the width of the remaining aluminum metal portion between the etching pits was 0.6 μm on average.
Next, the treated foil was immersed in a colloidally dispersed platinum catalyst for dehydrogenation to carry the platinum catalyst.
Next, said foil was divided into two, and as shown in FIG. 3, one side was continuously waved. The height of the corrugations of the corrugated processing was about 1 mm on average.
Next, in accordance with the shape of the hydrogen reaction vessel, the supported corrugated processed foil and the other flat foil were overlapped and wound into a coil to obtain a hydrogen catalyst member.

DESCRIPTION OF SYMBOLS 1 ... Aluminum foil, 2 ... Etching pit, 3 ... Anodized layer, 4 ... γ-alumina layer, 5 ... Convex deformation part

Claims (5)

  In a hydrogen catalyst member that is laminated or wound using an aluminum foil carrying a metal catalyst, and having a convex spacer formed by deforming the foil, the aluminum foil has pores. A hydrogen catalyst member characterized by having etching pits due to corrosion, leaving an aluminum metal portion between the etching pits, and having a feathery γ-alumina layer on the surface thereof.   The hydrogen catalyst member according to claim 1, wherein the height of the convex shape is 200 μm to 2000 μm. The hydrogen catalyst member according to claim 1 or 2, wherein a width of an aluminum metal portion between the etching pits is 0.3 µm to 3 µm. The hydrogen catalyst member according to claim 1, wherein the γ-alumina layer has a thickness of 0.1 μm to 1 μm. A step (a) of forming an etching pit by etching the surface of the aluminum foil;
A step (b) of performing a boehmite treatment on the surface of the aluminum foil subjected to the etching treatment, and further performing a firing treatment;
A step (c) of supporting a metal catalyst on the surface of the aluminum foil subjected to the baking treatment;
A step (d) of forming a convex shape by deforming the aluminum foil subjected to the baking treatment;
Using the aluminum foil obtained by the steps (a) to (d), obtaining a hydrogen catalyst member laminated or wound, and (e),
The method for producing a hydrogen catalyst member, wherein the aluminum foil obtained by the steps (a) to (d) leaves an aluminum metal portion between the etching pits.

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