JP2007069207A - Hydrogen separating composite and its production process - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen separating composite, which is free from pinholes and excessive penetration into a porous base material, has excellent stability, and has a high level of hydrogen permeability and a high level of hydrogen separation capability, and a process for producing the same. <P>SOLUTION: The process for producing a hydrogen separating composite comprises at least step A of forming a layer substantially formed of an easily burnable polymer containing a compound of a metal constituting a hydrogen separating layer formed of a metal on the surface of a porous base material, step B of stacking an electroless plating layer formed of a metal or alloy having a hydrogen separating function onto the surface of the layer, step C of heat treating the laminate to burn the easily burnable polymer, and step D of forming an electroless plating layer formed of a metal or alloy having a hydrogen separating function on the surface of the heat treated laminate. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hydrogen separation composite comprising at least a laminate of a porous substrate and a layer made of a metal or alloy having a hydrogen separation function, and a method for producing the same. More specifically, it has high permeability and extremely high hydrogen separation, no defects such as pinholes, virtually no penetration of the metal or alloy layer into the porous substrate, and high hydrogen permeability. The present invention relates to a hydrogen separation complex and a method for producing the same, which have high performance and extremely high hydrogen permeation separation ability and can maintain stability over a long period of time. In particular, the present invention relates to a hydrogen separation thin film having such characteristics and a method for manufacturing the same. Moreover, it is related with the laminated body for manufacture of the composite_body | complex. This hydrogen separation complex can be used in various applications. For example, it is suitable for hydrogen separation from hydrogen mixed gas, hydrogen production reaction, shift reaction, hydrogenation reaction, dehydrogenation reaction, and fuel cell application.

Hydrogen is regarded as a major future energy because it is lightweight, abundant and environmentally friendly. However, since hydrogen obtained from resources containing hydrogen such as water, natural gas, coal, and biomass contains impurities, it must be separated and purified before use. A number of techniques have been proposed for the separation and purification, such as a cryogenic separation method, an adsorption method, and a hydrogen separation method using a separation membrane.
Among these, the hydrogen separation method using a separation membrane has more advantages than other hydrogen separation methods in that it is more energy-saving, easier to operate, and can be downsized. The possibility of industrial use is great. In particular, a palladium-based composite metal membrane has a high hydrogen permeability and an excellent hydrogen separation property, and is clearly superior to other methods. In addition, it is possible to produce pure hydrogen useful for fuel cells and other hydrogen consuming processes, and to be used in hydrogenation and dehydrogenation reaction processes to improve the yield of target products. High value.
However, since palladium is expensive, for example, it is a less expensive metal such as nickel, copper, or vanadium, and a technique having a hydrogen separation ability similar to that of palladium has been actively studied.

  The Pd-based membranes that have been developed so far have a relatively large thickness, so the proportion of hydrogen produced relative to the raw material to be added is low, and the hydrogen permeation rate required for the accompanying chemical reaction rate is achieved. It has not yet been achieved, narrowing the possibilities for large-scale industrial applications. Therefore, a palladium-based composite thin film in which a thin palladium layer is formed on a porous substrate has been the focus of research in the field of hydrogen separation membranes, and the following technical information has been disclosed so far. .

  Patent document 1 (manufacturing technology of a gas separation thin film) discloses a method of forming an 11-33 μm palladium film on a porous ceramic substrate by a combination of electroless plating and electrolytic plating. However, the thickness of the membrane is large and the penetration of palladium into the substrate is not avoided. Therefore, the hydrogen selectivity of this palladium membrane is good, but the hydrogen permeation rate is low.

  In Patent Document 2 (hydrogen gas separation membrane), an inorganic porous material such as porous ceramics, porous glass, porous earthenware, or a metal filter is immersed in silica gel, alumina gel, or silica / alumina gel. Discloses a method for supporting a gel in the pores. These inorganic porous materials carrying silica gel and the like are dried, fired at a desired temperature, and then surface activated, followed by electroless plating, vacuum deposition, ion plating, or chemical vapor deposition. Thus, a palladium film is formed. However, when the microporous intermediate layer is formed in this way, the hydrogen permeation resistance is likely to increase.

In Patent Document 3, an intermediate layer of 50 μm thick SiO ₂ or Al ₂ O ₃ is formed to smooth the rough surface of a metal porous substrate, and then a palladium or palladium alloy film having a thickness of 2 to 20 μm is manufactured. Techniques to do this are disclosed. However, the presence of these oxide intermediate layers may increase the hydrogen permeation resistance.

  Patent Document 4 discloses a technique of coating a porous substrate with a gas separation membrane after removing impurities such as organic substances adhering to the surface of the porous substrate by treating the porous substrate. As a method for coating a gas separation membrane, a method is disclosed in which an electroless plating is performed after the base material is alternately struck to a hydrochloric acid aqueous solution of palladium chloride and a hydrochloric acid aqueous solution of tin chloride, heat-treated and alloyed.

  Patent Document 5 discloses a technique of laminating a 2.5-7 μm thick palladium film without a microporous intermediate layer. Although the manufacturing cost can be reduced by using a thin film, an operation for optimizing the average pore diameter of the porous substrate according to the thickness of the hydrogen separation membrane is necessary. There is room for improvement, with limitations that it is not free and a tendency to lower hydrogen selectivity.

  In Patent Document 6 and Patent Document 7, a chemical vapor deposition method is used to form a palladium thin film on a porous substrate. It can be said that this method is effective because a palladium thin film is surely formed. However, excessive penetration of the deposition raw material into the pores in the base material and the resulting decrease in hydrogen permeability are inevitable. .

  In Patent Document 8, a palladium or palladium alloy thin film is formed on the surface of a porous body by plating, and then a palladium compound is deposited on the thin film by chemical vapor deposition to form a palladium or palladium alloy thin film. Techniques to do this are disclosed. Further, a method is disclosed in which a rough surface of a porous substrate is improved by filling with water containing particles, and a palladium film is formed by plating palladium thereon. Although this method can be said to have eliminated the structural defects of the thin film, however, it cannot be said that excessive penetration of palladium into the substrate is avoided, and the hydrogen permeation rate is said to be decreasing. I cannot help it. In addition, there remains a risk of increased hydrogen permeation resistance due to the presence of particle residues on the substrate surface.

As described above, in the known method, the important process for introducing the palladium nucleus as the base of the palladium thin film has not been improved, and the high hydrogen permeability without penetration into the pinhole and the porous substrate is achieved. In addition, a method for producing a hydrogen separation composite thin film having high hydrogen separation properties has not yet been developed.
The same is true for known methods for hydrogen separation membranes made of metals other than palladium, and it can be said that there are almost no important steps for introducing metal nuclei that form the basis of thin films made of metals other than palladium. In addition, a method for producing a hydrogen separation composite thin film having high hydrogen permeability and high hydrogen separation without penetrating into a pinhole and a porous substrate has not yet been developed.

Japanese Patent Laid-Open No. 1-4216 JP-A-4-349926 JP-A-5-285357 JP-A-8-266876 JP 2000-317282 A JP 2003-62438 A JP 2003-135943 A JP 2004-122006 A

  Accordingly, it is an object of the present invention to present a method for solving these problems. That is, to provide a hydrogen separation composite having high hydrogen permeability and extremely high hydrogen separation without penetration into pinholes and porous substrates, and a method for producing the same, and to provide stability over a long period of time. It is to provide a hydrogen separation complex that can hold the same, and a method for producing the same. In particular, it is intended to provide a hydrogen separation composite thin film having high hydrogen permeability and extremely high hydrogen separation properties that do not penetrate pinholes and porous substrates, and a method for producing the same. It is to provide a hydrogen separation composite thin film that can hold the same, and a method for manufacturing the same.

  The inventors of the present invention have intensively studied to solve the above-mentioned problems, and as part of this, while focusing on the development of a process for introducing a palladium nucleus as a base of a palladium thin film with a simple operation, a palladium salt is contained in a polymer. Surprisingly, a palladium layer is easily and efficiently formed on the surface of the porous layer by electroless plating, and the laminate is heat-treated. It was found that when the polymer was burned off, the palladium salt coexisting in the polymer remained on the porous surface, and the above problem could be solved. Based on the findings, the present inventors have further studied and finally completed the present invention.

That is, the invention of claim 1 includes the step A of forming a layer consisting essentially of an easily burnable polymer containing a metal compound constituting a hydrogen separation layer made of metal on the surface of the porous substrate. Hydrogen separation comprising at least a step B of laminating a layer made of a metal or alloy having a hydrogen separation function on the surface of the layer, and a step C of heat-treating the easily burnable polymer by heating the laminate. The present invention relates to a method for producing a composite. Here, “a metal compound constituting a hydrogen separation layer made of metal” (hereinafter sometimes referred to as a metal compound) is “a metal compound, and the metal is a metal constituting the hydrogen separation layer”. Means. In addition, “a layer substantially composed of a readily burnable polymer containing a metal compound that constitutes a metal hydrogen separation layer” means “a layer containing a metal compound and a readily burnable polymer as essential components” In other words, it means a layer in which other components may coexist as long as the intended purpose can be achieved.
The invention according to claim 2 is a process A for forming a layer consisting essentially of an easily burnable polymer containing a metal compound constituting a metal hydrogen separation layer on the surface of a porous substrate, Step B of laminating a layer made of a metal or alloy having a hydrogen separation function on the surface, Step C of heat-treating the laminate to burn away the easily burnable polymer, and the laminate obtained by the heat treatment The present invention relates to a method for producing a hydrogen separation composite comprising at least a step D of forming a layer made of a metal or alloy having a hydrogen separation function on the surface.

The invention of claim 3 is characterized in that in the inventions of claims 1 and 2, the method further comprises a step E of heat-treating the base material on which the layer obtained in step A is formed. In any one of the inventions 1 to 3, the metal constituting the hydrogen separation layer composed of a metal compound comprising a hydrogen separation layer composed of a metal, an easily burnable polymer, and an organic solvent in Step A It is characterized by substantially consisting of applying and impregnating a porous substrate with a solution containing the above compound. Here, “a solution containing a metal compound constituting a hydrogen separation layer comprising a metal compound comprising a metal separation layer comprising a metal, a readily burnable polymer, and a metal comprising a hydrogen separation layer comprising an organic solvent is a porous group. "Applying and impregnating to a material" means applying a solution containing a metal compound composed of a metal compound, an easily burnable polymer, and an organic solvent to a porous substrate, and a metal compound. , Impregnating a porous substrate with a solution containing a metal compound composed of an easily burnable polymer and an organic solvent, or both.
The invention of claim 5 is the process according to any one of claims 1 to 3, wherein step B is a step of laminating an electroless plating layer made of a metal or alloy having a hydrogen separation function on the surface of the layer in step A. It is characterized by being.

The invention of claim 6 includes a porous substrate K, a layer L made of an easily burnable polymer containing a metal compound constituting a metal hydrogen separation layer, a layer made of a metal or palladium alloy having a hydrogen separation function. The present invention relates to a laminate for producing a hydrogen separation composite.
The invention of claim 7 is the invention of claim 6, wherein the layer M is an electroless plating layer made of a metal or alloy having a hydrogen separation function. The invention of claim 8 relates to a hydrogen separation complex obtained by heat-treating the laminate of claim 6 or 7. When the laminate according to claim 6 or 7 is heated, the easily burnable polymer existing in the laminate is burned away.
A ninth aspect of the present invention relates to a hydrogen separation complex characterized in that N made of a metal or alloy having a hydrogen separation function is further formed on the surface of the hydrogen separation complex of the eighth aspect.
The invention of claim 10 is the invention of claim 9, wherein the layer N is an electroless plating layer made of a metal or alloy having a hydrogen separation function.
The invention of claim 11 is the hydrogen separation complex according to any one of claims 6 to 10, wherein the thickness of the layer M is 0.5 to 5 μm. In the present invention, the hydrogen separation composite can be referred to as a hydrogen separation composite membrane.
The invention of claim 12 is the hydrogen separation complex according to any one of claims 6 to 10, wherein the thickness of the layer N is 0.5 to 10 μm. In the present invention, the hydrogen separation composite can be referred to as a hydrogen separation composite membrane. That is, the hydrogen separation composite of the present invention is characterized in that the thickness of the layer made of a metal or alloy having a hydrogen separation function, that is, the layer M and the layer N are 1 to 15 μm.

The invention of claim 13 is a laminate comprising at least a porous substrate and a layer made of a metal or alloy having a hydrogen separation function, and further comprising a porous group of a layer made of a metal or alloy having a hydrogen separation function The present invention relates to a hydrogen separation composite characterized by substantially no penetration into the material. In addition, the layer made of a metal or alloy having a hydrogen separation function does not have pinhole defects. Here, “substantially no penetration of a layer made of a metal or alloy having a hydrogen separation function into a porous substrate” means that a layer made of a metal or alloy having a hydrogen separation function is applied to the porous substrate. It means that there is no permeation or it is observed slightly but has little effect on hydrogen permeability and hydrogen permeation separation ability. Here, it is a laminate composed of at least a porous substrate and a layer made of a metal or alloy having a hydrogen separation function, and further to a porous substrate made of a metal or alloy having a hydrogen separation function. The hydrogen separation complex according to any one of claims 6 to 12 is also included.
The invention of claim 14 is a laminate comprising at least a porous substrate and a layer made of a metal or alloy having a hydrogen separation function, and further, the porous substrate and the metal or alloy having the hydrogen separation function. It is related with the hydrogen-separation composite characterized by hold | maintaining a space layer substantially between the layers which consist of. Here, “maintaining a spatial layer substantially between the porous substrate and the layer made of the metal or alloy having a hydrogen separation function” means having the porous substrate and the hydrogen separation function. Although the space layer is held between the layers made of metal or alloy, or a part of the space layer is difficult to observe, a book on hydrogen permeability, hydrogen permeation separation ability, mechanical stability, etc. It means when there is almost no influence on the features of the invention. This spatial layer essentially serves as a buffer layer. The present invention is a laminate comprising at least a porous substrate and a layer made of a metal or alloy having a hydrogen separation function, and further comprising the porous substrate and the metal or alloy having a hydrogen separation function. A hydrogen separation complex according to any one of claims 6 to 12 is also included, wherein a space layer is substantially retained between the layers.
The invention according to claim 15 is a laminate comprising at least a porous substrate and a layer made of a metal or alloy having a hydrogen separation function, and the porous group of the layer made of a metal or alloy having a hydrogen separation function A hydrogen separation complex characterized in that there is substantially no penetration into the material and a space layer is substantially maintained between the porous base material and the metal or alloy layer having a hydrogen separation function. About. Here, “substantially hold a space layer between the porous substrate and the metal or alloy layer having a hydrogen separation function” is as described above. The present invention is a laminate comprising at least a porous substrate and a layer made of a metal or alloy having a hydrogen separation function, and further comprising a porous substrate made of a metal or alloy having a hydrogen separation function 13. A space layer is substantially maintained between the porous base material and the metal or metal alloy layer having a hydrogen separation function. The hydrogen separation complex described in any of the above is also included.

  The hydrogen separation composite of the present invention is free from structural defects such as pinholes, and is substantially free from entering the pores of a porous substrate of a metal or alloy layer having a hydrogen separation function. One of the features is that it has excellent hydrogen permeability, extremely high hydrogen separation properties, and long-term stability. Further, the hydrogen separation composite of the present invention is a thin film, and the porous base material and the layer made of a metal or alloy having a hydrogen separation function are separated from a space thin layer that substantially serves as a buffer layer. Therefore, the thermal expansion / contraction associated with hydrogen adsorption / desorption and thermal cycle is not directly affected, and the mechanical strength and long-term stability are excellent. Further, the space layer has a thickness of, for example, about 0.1 to 1 μm, and has a feature that the surface area is greatly improved.

  Further, the present invention is characterized by a method for preparing such a hydrogen separation composite, and in particular, a porous substrate activation process utilizing a novel catalyst technology and a metal thin film layer formation process. . That is, (1) a layer containing a metal compound constituting a hydrogen separation layer made of metal in an easily burnable polymer is formed on a porous substrate, and a metal nucleus serving as a base of the hydrogen separation layer made of metal is formed (2) A relatively large amount of a metal compound formed on the surface of a porous substrate by a single coating operation with a solution composed of at least a burnable polymer, a metal compound, and a solvent. Is uniformly dispersed and a layer having a uniform thickness can be formed, so that the metal nuclei that are the base of the hydrogen separation layer made of metal are uniformly dispersed in a large amount, and in addition, it is necessary for the production of a hydrogen separation membrane. (3) Since a layer made of a metal or alloy having a hydrogen separation function can be formed on the surface of a layer containing an easily burnable polymer, the layer is thin and has a defect. Since there is no layer, hydrogen permeability For excellent hydrogen separation performance, characterized by such.

It can be seen that the hydrogen separation composite of the present invention and the production method thereof are extremely superior as compared with the conventional hydrogen separator and the production method thereof.
That is, in the conventional method for producing a hydrogen separator by the electrolytic plating method, the step of heat treatment is performed about 10 times after the porous substrate is immersed in each solution containing a metal having a hydrogen separation function. A metal nucleus serving as a base for metal plating having a hydrogen separation function was formed on the surface of the substrate. This leads to an increase in the thickness of the hydrogen separation layer, which is a plating film, and the hydrogen permeability is inevitably reduced. Furthermore, the distribution of metal nuclei tends to be non-uniform, the thickness of the hydrogen separation layer is non-uniform, and there is a possibility that locations with a thickness of 1 μm or less where defects are likely to occur are mixed. Moreover, it takes time to form the hydrogen separation layer, and the cost is high. In order to avoid these points, if the heat treatment step is reduced to several times, the amount of metal nuclei serving as the base of the hydrogen separation layer made of metal is small, and the dispersion is not uniform.
Furthermore, since the hydrogen separator obtained by a conventional manufacturing method is in close contact with the base material and the hydrogen separation layer made of metal, the thermal expansion / contraction associated with hydrogen adsorption / desorption and thermal cycle is directly observed. The mechanical strength and long-term stability are poor.

Hereinafter, the present invention will be described in detail.
The porous substrate constituting the composite of the present invention may be any porous substrate used in this field, and is not particularly limited. For example, a base material having a shape including a flat surface and a curved surface, or a tubular base material such as a hollow fiber or tube having a circular or elliptical cross section can be employed.
This substrate has a large number of fine pores that are three-dimensionally continuous, and it is preferable that the pore diameters be as uniform as possible. The thickness of the porous substrate is not particularly limited as long as sufficient mechanical strength can be maintained in the use environment. For example, a base material of about 50 μm to 5 mm can be used. The pores of the porous substrate are not particularly limited as long as the intended purpose of the present invention can be achieved. For example, a substrate having a pore diameter of about 0.001 μm to 100 μm can be used. A substrate having a pore diameter of about 05 μm to 10 μm is more preferable. Moreover, it is preferable that the porosity of a base material is 20 to 60%. Moreover, it is preferable that the internal diameter of the porous base material to be used is about 200 micrometers-20 mm.
These substrates are preferably made of an inorganic material, and are advantageously a material that does not react with the raw material gas passing through the pores. Specific examples include stainless steel, alumina, silica-alumina, zirconia, carbon, silicon carbide, and glass.

  Although these base materials may be used for the production of a hydrogen separation composite without pretreatment, it is advantageous to perform pretreatment such as washing treatment and drying treatment. Specifically, a pretreatment in which the substrate is washed with one or more selected from acids, bases, various alcohols, water and the like, and then dried is preferable. In the cleaning treatment, it is more advantageous to use a physical treatment such as ultrasonic treatment for about 1 to 60 minutes. More specifically, the pretreatment is preferably performed by ultrasonic cleaning in turn with dilute acid, dilute base, ethanol and distilled water, and drying in an oven at 50 to 200 ° C. for about 30 minutes to 3 hours.

  One of the features of the present invention is that the porous substrate is provided with a layer substantially composed of an easily burnable polymer containing a metal compound that constitutes a metal hydrogen separation layer. is there. For example, a solution or dispersion containing a metal compound constituting a hydrogen separation layer made of metal and an easily burnable polymer is prepared, and the solution or dispersion is applied to or impregnated on the substrate. A layer made of an easily burnable polymer containing a metal compound constituting a hydrogen separation layer made of metal can be provided on the porous base material by heat treatment. The composition of the above solution or dispersion cannot be unconditionally specified because it varies depending on the type of metal compound and easily burnable polymer constituting the hydrogen separation layer made of the metal to be used, but a preferred solution composition is 0.001-5 wt%. It is composed of a metal compound that constitutes a hydrogen separation layer composed of the above metals, 0.5 to 20 wt% of an easily burnable polymer, and 75 to 99 wt% of an organic solvent, but the present invention is limited to this composition range. Not.

The metal constituting the hydrogen separation layer made of the metal is a metal already known as a metal having hydrogen separation ability, for example, palladium, nickel, platinum, copper, silver, vanadium, gold, cobalt, rhodium, iridium. , Iron, ruthenium, niobium, tantalum, hafnium, titanium, and one or more selected from the group consisting of zirconium.
Examples of the metal compound constituting the hydrogen separation layer made of metal include palladium acetate, palladium acetate, palladium acetylacetonate, palladium ammonium chloride, palladium bromide, palladium chloride, palladium diamine nitrate, palladium nitrate, and hydroxide. It is preferable to use one or more selected from the group consisting of palladium, palladium ethylenediamine nitrate, palladium nitrate hydrate, palladium oxalate, palladium sulfate hydrate, and palladium tetraamine dinitrate. It is not limited to.

Nickel compounds include nickel acetate, nickel acetylacetonate, nickel ammonium chloride, nickel bromide, nickel carbonate, nickel chloride, nickel nitrate diamine, nickel nitrate, nickel ethylenediamine nitrate, nickel nitrate hydrate, nickel oxalate, water It is preferable to use one or more selected from the group consisting of nickel oxide, nickel sulfate hydrate, and nickel tetraamine dinitrate, but it is not limited to these compounds.
As the platinum compound, it is preferable to use one or two or more kinds selected from the group consisting of platinum acetylacetonate, platinum chloride, dinitroammineplatinum and potassium tetranitroplatinate, but not limited to these compounds.

Copper compounds include copper acetate, copper acetate hydrate, copper acetylacetonate, copper bromide, copper carbonate, copper chloride, copper chloride hydrate, copper citrate, copper butyrate, diammonium copper hydrate , Copper phosphate hydrate, copper fluoride, copper gluconate, copper iodide, copper naphthenate, copper nitrate hydrate, copper oleate, copper phthalate, copper sulfate, copper terephthalate hydrate, and thiocyanic acid Although it is preferable to use 1 type, or 2 or more types selected from the group consisting of copper, it is not limited to these compounds.
As the silver compound, one or more selected from the group consisting of silver acetate, silver acetylacetonate, silver bromide, silver carbonate, silver chloride, silver nitrate, silver nitrite, silver sulfate, and silver thiocyanate are used. However, the present invention is not limited to these compounds.
As the compound of vanadium, one or two kinds selected from the group consisting of vanadic anhydride, vanadium chloride, vanadium naphthenate, vanadium oxide sulfate, vanadium oxytrichloride, vanadium oxide acetylacetonate, and vanadyl oxalate hydrate. Although it is preferable to use the above, it is not limited to these compounds.

  Gold compounds include potassium gold cyanide, gold (1) sodium cyanide, gold (I) cyanide, potassium dicyanogold (I), sodium dicyanogold (I), potassium tetrachlorogold (3), tetra Potassium chloroaurate (3) hydrate, tetrachloroaurate (3) tetrahydrate [gold chloride (3) acid; chloroauric acid], sodium tetrachloroaurate (III) dihydrate, tetrachloro Gold (III) acid trihydrate, potassium tetrachloroplatinum (2), ammonium tetrachloroplatinum (II), potassium tetrachloroplatinum (II), bis (benzonitrile) platinum (II) chloride, hexachloroplatinum (4) Potassium acid, hexachloroplatinum (4) sodium, hexachloroplatinum (4) acid hexahydrate [platinum chloride (IV) acid hexahydrate], hexachloroplatinum (4) acid hexahydrate [platinum chloride (IV) acid hexahydrate], ammonium xachloroplatinate (IV), potassium hexachloroplatinate (IV) , Hexachloroplatinic acid (IV) hexahydrate, potassium hexacyanoplatinum (IV), sodium chloride (3) dihydrate, gold chloride (3) sodium, gold chloride (3) acid tetrahydrate, chloride It is preferable to use one or two or more kinds selected from the group consisting of n-hydrate gold acid, platinum chloride (2) [platinum chloride], but it is not limited to these compounds.

  Examples of cobalt compounds include cobalt 2-ethylhexanoate (2), cobalt amidosulfate (II) tetrahydrate, ethylenediaminetetrasuccinate disodium cobalt, ethylenediaminetetraacetic acid disodium cobalt (2), ethylenediaminetetraacetic acid disodium cobalt Salt tetrahydrate, cobalt oleate, cobalt formate (2) dihydrate, cobalt (II) citrate, cobalt (2) acetylacetonate, cobalt (2) acetylacetonate dihydrate, cobalt cyanide (3) potassium, cobalt cyclohexanebutyrate, cobalt oxalate (II) dihydrate, cobalt stearate, tris (2,4-pentanedionato) cobalt (3), naphthenic cobalt, cobalt phosphate (2), It is preferable to use one or more selected from the group consisting of sodium cobalt (3) nitrite, but these compounds It is not limited to things.

  Rhodium compounds include (acetylacetonato) (η-cycloocta-1,5-diene) rhodium (I), (acetylacetonato) dicarbonylrhodium (I), carbonyltris (triphenylphosphine) rhodium (I) Hydride, Chlorocarbonylbis (triphenylphosphine) rhodium (I), Tetrakis (N-phthaloyl- (S) -phenylalaninato) dirhodium, Sachet kabutsu, Tris (triphenylphosphine) rhodium chloride, Norbornadiene rhodium chloride, Bis (1, One or more selected from the group consisting of 5-cyclooctadiene) dichlorodichlorodium, rhodium (III) chloride (anhydrous) and rhodium nitrate (3) are preferably used, but are not limited to these compounds.

  As the organic solvent, one or more selected from the group consisting of methanol, N-methyl-2-pyrrolidone (NMP), carbon tetrachloride, propanol, butanol, chloroform, ethanol, acetone, benzene, acetic acid, and toluene However, it is not limited to these solvents.

  The easily burnable polymer referred to in the present invention is a polymer that forms a film on the surface of a porous substrate, is a polymer that is burned off by a subsequent heat treatment, and is a metal compound constituting the hydrogen separation layer that coexists. The polymer is not particularly limited as long as the polymer has a function capable of being dispersed. As the easily burnable polymer, organic polymers are suitable. Specifically, poly (vinyl alcohol), poly (vinyl butyral), poly (vinyl pyrrolidone), poly (ethylene glycol), poly (2 , 6-dimethyl-4-phenylene oxide), phenol resin, polyester, polyamide, polyimide, polyamideimide, polyvinyl chloride, polyvinylidene chloride, poly (ether sulfone), polyolefin, and polystyrene, Two or more types are preferably used, but are not limited to these polymers.

  After the metal compound constituting the hydrogen separation layer made of the above metal is dissolved or dispersed in an organic solvent at 20-100 ° C., the above-mentioned easily burnable polymer is made into the hydrogen separation layer made of this metal. By dissolving or dispersing in a metal compound solution, a uniform metal compound-containing easily burnable polymer activating solution or dispersion is prepared.

The method for applying the metal compound-containing easily burnable polymer solution or dispersion thus prepared to the porous substrate is not particularly limited. For example, the metal compound-containing easily burnable polymer solution is applied to the porous substrate by osmotic brushing, spin coating, reduced pressure dip coating, reduced pressure impregnation, reduced pressure brushing, reduced pressure spin coating, ultrasonic dip coating, ultrasonic wave-reduced pressure. It can apply | coat by the method chosen from dip coating, ultrasonic impregnation, and ultrasonic-vacuum impregnation. In particular, it is preferable to apply the palladium salt-containing easily burnable polymer solution to the washed porous substrate by the above method about 1 to 10 times, preferably about 1 to several times. One application / impregnation may be performed.
The coating and impregnation methods described above are known methods, and are not particularly limited when these methods are actually applied. Specifically, for example, it is desirable that the porous substrate is dipped in the above solution for 1 to 600 seconds and then rapidly pulled up.
Subsequently, the porous substrate is heat-treated, and a metal compound-containing polymer layer is formed on the surface of the porous substrate. The heat treatment is not particularly limited as long as a metal compound-containing polymer layer is formed on the surface of the porous substrate.
By these operations, the metal compound-containing polymer thin film is laminated on the porous substrate surface, the metal compound-containing polymer is appropriately entered into the pores of the metal substrate, or both. A compound-containing polymer layer is formed.

After forming a layer consisting essentially of an easily burnable polymer containing a metal compound that constitutes a metal hydrogen separation layer, a metal hydrogen separation layer is constructed by various known methods such as palladium electroless plating. A layer substantially consisting of an easily burnable polymer containing a metal compound to be formed may be formed, but before that, the porous substrate on which the metal compound-containing polymer thin film layer is formed is subjected to heat treatment It is advantageous. By this heat treatment, it is presumed that the metal compound is converted into a metal nucleus that can be easily grown thereafter. As an example of specific conditions for heat treatment, the porous substrate is heated at 100 to 600 ° C. in an atmosphere of argon, helium, air, water vapor, still air, etc. for 0.1 to 10 hours. is there.
When this heat treatment is performed, the heat treatment described in paragraph 0023 does not have to be performed.
In the present invention, it is preferable to perform a reduction treatment after the heat treatment. However, advantageous results can be obtained even if the reduction treatment is performed without the heat treatment. The means and conditions for the reduction treatment are not limited as long as they are conditions for reducing metal nuclei derived from metal compounds. Specifically, reduction treatment in a hydrogen stream is preferable.

A metal or alloy having a hydrogen separation function in a laminate of a porous base material in which a layer consisting essentially of an easily burnable polymer containing a metal compound constituting a hydrogen separation layer comprising a metal thus prepared is formed A layer consisting of The layer substantially composed of the easily burnable polymer containing the metal compound constituting the metal hydrogen separation layer is preferably a layer substantially composed of the easily burnable polymer containing the palladium salt.
A layer made of a metal or alloy having a hydrogen separation function is formed on a laminate of a porous base material in which a layer consisting essentially of an easily burnable polymer containing a metal compound constituting a metal hydrogen separation layer is formed. The method of laminating is not particularly limited as long as the intended purpose can be achieved. Specifically, it can be laminated by a CVD method, a sputtering method, an electrolytic plating method, an electroless plating method, or the like. Among these methods, the electroless plating method is preferable.
A method of laminating a layer made of a metal or alloy having a hydrogen separation function using these methods is not particularly limited as long as a Kochi method is applied.
The layer consisting essentially of an easily burnable polymer containing a metal compound constituting the metal hydrogen separation layer was a layer having a uniform thickness and improved operability. A layer made of a metal or alloy having a hydrogen separation function is also a layer having a uniform thickness.

Hereinafter, a preferable electroless plating method will be described. In the following description, palladium or a palladium alloy is selected and described as the metal or alloy having a hydrogen separation function.
The pre-electroless plating method employed for forming a palladium or palladium alloy thin film on the palladium-containing polymer thin film layer on the surface of the porous body is not particularly limited, and a method used in this field is appropriately selected. Can be used. What is necessary is just to select suitably according to the kind, shape, desired performance, etc. of the porous base material to be used. Further, the electroless plating method may be applied in combination with other methods such as an electroplating method.
Specific plating conditions are not particularly limited, and plating may be performed according to known conditions using a known plating bath capable of forming a target palladium or palladium alloy thin film. When a non-conductive porous substrate is used, for example, a catalyst for electroless plating may be applied according to a known method, and then a palladium or palladium alloy thin film may be formed by the electroless plating method.
In order to improve the adhesion of the plated film to be formed, a method of press-fitting a plating solution into the pores from one surface of the porous body can be employed when forming the plated film.
Specifically, a method using a commercially available palladium plating bath (Paratop, Okuno Kogyo Co., Ltd.) having a pH of 3 to 12 under the conditions of a plating temperature of 20 to 80 ° C. and a plating time of 0.05 to 3 hours is exemplified. it can.

The plating film may be formed on the entire surface of the porous base material, or may be formed on a surface in contact with a hydrogen-containing gas as a raw material to be introduced when used as a hydrogen separator. When a hollow tubular porous substrate is used, for example, a plating film may be formed on the outer surface.
The thickness of the layer made of a metal or alloy having a hydrogen separation function formed by the pre-electroless plating method is preferably about 0.5 to 20 μm, more preferably about 0.5 to 10 μm. . If the thickness of the thin film is too thin, the hydrogen selective separation performance becomes insufficient. On the other hand, if the thickness is too thick, economic efficiency is lost.

  As the palladium alloy in the separation composite, an alloy of palladium and one or more kinds of noble metals selected from the group consisting of silver, gold, copper, platinum, nickel and cobalt is preferable. The proportion of palladium in such a palladium alloy is preferably about 55% by weight or more.

One of the characteristics of the present invention is to heat-treat the laminate that has been subjected to the pre-layer electroless plating treatment, which is substantially composed of an easily burnable polymer containing a metal compound constituting the metal hydrogen separation layer. It is. By this heat treatment, the easily burnable polymer is burned out and removed from the laminate, and a hydrogen separation composite can be produced.
The shape of this hydrogen separation composite varies depending on the porous substrate used, the thickness of the plating film formed by the previous electroless plating method, etc., but the layer containing palladium or palladium alloy has a pinhole structure It has no significant defects and has an excellent hydrogen separation function.
The above heat treatment conditions vary depending on the porous substrate, palladium salt, easily burned polymer, etc. used, but cannot be defined unconditionally. However, as specific heat treatment conditions, the laminate may be placed in an air stream or stationary. In the presence of a mixture of pure oxygen and oxygen-nitrogen in the air, the temperature was increased to 300 to 1100 ° C. at a temperature rising rate of 0.2 to 20 ° C. per minute, and heat treatment was performed by holding at that temperature for 0.1 to 20 hours. Then, the temperature lowering condition can be exemplified to room temperature at a temperature lowering rate of 0.2 to 20 ° C. per minute.
The hydrogen separation complex thus obtained exhibits an excellent hydrogen separation ability. For example, the hydrogen separation coefficient is 1000 or more. Here, the hydrogen separation coefficient is a value obtained based on the following equation.
Hydrogen separation factor = P _H2 / P _He
In the formula, P _H2 represents the permeation rate of hydrogen, and P _He represents the permeation rate of helium. The hydrogen permeation rate is determined by supplying hydrogen at a predetermined pressure from one surface of the separation membrane and measuring the permeation rate of hydrogen permeating from the other surface. Subsequently, after the inside of the measurement system is cleaned with helium gas, helium is supplied under the same conditions, and the permeation rate of helium permeating from the other surface is measured.

Hydrogen was again added to the hydrogen separation composite obtained by removing the easily burnable polymer layer from the layer consisting essentially of the easily burnable polymer containing the metal compound constituting the hydrogen separation layer comprising the metal thus obtained. A layer made of a metal or alloy having a separation function is formed and applied, and a hydrogen separation composite having excellent characteristics such as a hydrogen separation function can be obtained.
Here, as a method of forming a layer made of a metal or alloy having a hydrogen separation function, a known method can be used as described above, and among these, an electroless plating method is preferable. The same method as described above can be applied to the conditions for performing the electroless plating treatment.
The thickness of a metal or metal alloy layer having a hydrogen separation function, particularly a palladium or palladium alloy thin film formed by electroless plating is preferably about 0.5 to 20 μm, preferably 0.5 to 10 μm. More preferably, it is about 1-10 micrometers.
Specific conditions are as follows: dipping into a commercial palladium plating bath (Paratop, Okuno Kogyo Co., Ltd.) having a pH of 3 to 12 under conditions of a plating temperature of 20 to 80 ° C. and a plating time of 0.1 to 20 hours. Subsequently, the conditions which dry the obtained palladium composite film in still air at 50-300 degreeC for 0.5 to 20 hours can be illustrated.
The shape of this hydrogen separation composite varies depending on the porous substrate used, the thickness of the plating film formed by the electroless plating method, etc., but the layer containing palladium or a palladium alloy has a structure in which pinholes exist. There are no significant defects, the penetration into the porous substrate is moderate, and it has excellent characteristics such as having an excellent hydrogen separation function.

  The hydrogen permeation characteristics of the thus produced hydrogen separation composite were measured under the conditions of a measurement temperature of 200-900 ° C, more preferably 300-600 ° C, a differential pressure of 0-1000 kPa, more preferably 0-200 KPa. .

  The hydrogen separation composite of the present invention can be applied over a wide range and is suitable for hydrogen separation from hydrogen mixed gas, hydrogen production reaction, shift reaction, hydrogenation reaction, dehydrogenation reaction, fuel cell application, etc. Yes. More specifically, it can be applied to the purification of reformed gas, and high-purity hydrogen fuel can be supplied as household fuel, or can be applied to an on-vehicle fuel cell. In addition, it can be applied to hydrogenation and dehydrogenation reactions using a hydrogen permeation reactor. Furthermore, it can be applied to various synthetic chemistry related to hydrogen, petroleum refining, metal refining and the like.

According to the present invention, there is no defect such as pinholes, there is no permeation to the porous substrate of a layer made of a metal or alloy having a hydrogen separation function represented by palladium or palladium alloy, high hydrogen permeability and extremely high hydrogen It is characterized by having permeation separation ability and maintaining stability over a long period of time. In particular, since the porous substrate and the layer made of metal or alloy having hydrogen separation function exist across the space thin layer (buffer layer), thermal expansion / contraction associated with hydrogen adsorption / desorption and thermal cycle is directly observed. Therefore, a hydrogen separation composite having excellent mechanical strength and long-term stability can be obtained. In addition, the layer made of a metal or alloy having a hydrogen separation function is uniform, and is formed in a short time, so that the cost is also reduced.
This hydrogen separator is suitable for application to hydrogen separation from hydrogen mixed gas, hydrogen production reaction, shift reaction, hydrogenation reaction, dehydrogenation reaction, and fuel cell.

Based on FIG. 6, the preparation process of the hydrogen separation complex in this invention is shown.
2 shows a cross-sectional structure (two on the right side) of an example of the hydrogen separation complex of the present invention and a composite cross-sectional structure (three on the left side) that is positioned as a raw material for preparing the hydrogen separation complex. When the five cross-sectional structures in FIG. 6 are sequentially numbered (1), (2), (3), (4) and (5) from the left side, (1) is the cross-sectional structure of the substrate, (2) shows a cross-sectional structure when a layer (activation layer) substantially composed of a metal compound and an easily burnable polymer is formed (step A), and has a hydrogen separation function on the surface of (2). A cross-sectional structure when a layer made of a metal or an alloy is laminated (step B) is indicated by (3), a cross-sectional structure obtained by heat-treating (3) is indicated by (4), and hydrogen is further formed on the surface of (4). A cross-sectional structure in which layers made of a metal or alloy having a separation function are stacked is shown by (5). The hydrogen separation composites represented by the cross-sectional structures (4) and (5) are characterized in that an extremely thin stress relaxation layer is formed and there are no defect pinholes.
This process has high permeability and extremely high hydrogen separation, no defects such as pinholes, virtually no penetration of the metal or alloy layer into the porous substrate, and high hydrogen permeability. It can be seen that it is possible to produce a hydrogen separation complex characterized by having a high performance and extremely high hydrogen permeation separation ability and maintaining stability over a long period of time. In addition, according to this process, in addition to the hollow fiber-like porous substrate, the above-mentioned features are applied to the upper surface, the back surface, locally or the entire surface of various forms of substrates such as a tubular substrate and a porous disk. It is possible to produce a hydrogen separation complex having the same.

Hereinafter, the present invention will be described in detail based on examples. However, the present invention is not limited to the following examples.
Example 1
(A) (Preparation of solution for activation of palladium-containing polymer)
After adding 5.4 g of poly (2,6-dimethyl-4-phenylene oxide) (PPO) to 100 mL of chloroform and stirring at room temperature, 1.2 g of palladium acetate was added and stirred to prepare an activation solution containing a palladium-containing polymer. Prepared.

(B) (Preparation of production raw material for hydrogen separation complex)
Hollow fiber-shaped α-Al ₂ O ₃ porous substrate with inner diameter 2.2mm, outer diameter 2.9mm, film thickness 350μm, average pore diameter 0.15μm, porosity 52% with dilute acid, dilute base, ethanol, distilled water Then, ultrasonic cleaning was sequentially performed at room temperature for 5 minutes each and dried in an oven at 100 ° C. for 2 hours. In order to form a thin film layer, the washed hollow fiber-like α-Al ₂ O ₃ porous substrate was dipped in the activation solution of Example 1 (a) for 5 seconds and then rapidly pulled up. Next, after the formed hollow fiber was dried in still air for 2 hours, the temperature was increased to 350 ° C. at a temperature increase rate of 5 ° C. per minute, and the temperature was maintained for 3 hours. did. The pre-electroless plating treatment is performed using a commercially available palladium plating bath (Paratop, Okuno Kogyo Co., Ltd.) having a pH of about 7 under the conditions of a plating temperature of 40 ° C. and a plating time of 1 hour. A palladium composite membrane as a production raw material was obtained.

(C) (Preparation of hydrogen separation complex)
The palladium composite membrane subjected to the pre-electroless plating treatment obtained in Example 1 (b) is heated to 700 ° C. at 2 ° C./min in still air and held at that temperature for 5 hours. Heat treatment. Next, the temperature was lowered to room temperature at a rate of 5 ° C. per minute to obtain a hydrogen separation complex.

(Example 2) Preparation of hydrogen separation complex The hydrogen separation complex obtained in Example 1c was again subjected to a commercial palladium plating bath (paraffin) having a pH of about 7 under the conditions of a plating temperature of 40 ° C and a plating time of 2 hours. Dip to the top, Okuno Kogyo Co., Ltd. Finally, the obtained palladium composite membrane was dried in still air at 100 ° C. for 3 hours to obtain a hydrogen separation composite (palladium composite membrane).
The form of the palladium composite membrane is shown in FIGS. 1a and b. Clearly, a pinhole-free palladium layer with a uniform thickness of about 5 μm was prepared. Moreover, it can be seen that there is no penetration of palladium into the pores of the substrate. Thanks to the smooth and dense polymer membrane layer on the surface, it can be seen that by removing this, a pinhole and non-penetrated palladium thin film is plated directly onto the macroporous substrate.

(Test Example 1) Relationship between hydrogen permeation flux of palladium composite membrane and hydrogen pressure difference The relationship between hydrogen permeation flux of palladium composite membrane and hydrogen pressure difference is shown in FIG. It can be seen that the hydrogen permeation flux increases remarkably as the hydrogen pressure difference increases. A high hydrogen permeation flux of 0.82 mol / (s m2) was obtained with a hydrogen pressure difference of 200 kPa at 600 ° C.

(Test Example 2) Relationship between hydrogen permeation flux of palladium composite membrane and operating temperature The relationship between the hydrogen permeation flux of palladium composite membrane and the operating temperature is shown in FIG. It can be seen that increasing the operating temperature while maintaining the hydrogen pressure difference significantly increases the hydrogen permeation flux.

Test Example 3 Stability and Operating Time of Palladium Composite Membrane FIG. 4 shows the relationship between the stability and operating time of the palladium composite membrane. It can be seen that the hydrogen permeation flux is stable at about 0.34 mol / (sm ² ) during 200 hours of operation at a pressure difference of 100 kPa and 500 ° C.

(Test Example 4) Stability of hydrogen permeation with respect to the number of hydrogen and helium exchange cycles of the palladium composite membrane FIG. 5 shows the stability of hydrogen permeation with respect to the number of hydrogen and helium exchange cycles of the palladium composite membrane. It can be seen that the hydrogen permeation flux is stable even when the number of cycles is increased to 40.

Even after the film stability test, the helium leak value was negligibly small even when a pressure difference of 300 kPa was applied. That is, it can be said that the palladium composite membrane produced by this method has infinite hydrogen selectivity.
Example 3

(A) (Preparation of copper plating bath)
Mix and agitate 1.8 mL of 4 mg / L 2,2-bipyridyl solution, 0.8 mL of 16 mg / L TritonX-100 solution, 2 g of copper sulfate, 10 g of Na2EDTA, 10 g of sodium hydroxide, and 7 mL of formaldehyde, and then add 1 L of copper plating solution. Was prepared.

(B) (Preparation of production raw material for hydrogen separation complex)
A hollow fiber-shaped α-Al ₂ O ₃ porous substrate having an inner diameter of 2.2 mm, an outer diameter of 2.9 mm, a film thickness of 350 μm, an average pore diameter of 0.15 μm, and a porosity of 52% is diluted with dilute acid, dilute base, ethanol, The sample was ultrasonically washed with distilled water at room temperature for 5 minutes each, and dried in an oven at 100 ° C. for 2 hours. In order to form a thin film layer, the washed hollow fiber-like α-Al ₂ O ₃ porous substrate was dipped in the activation solution of Example 1 (a) for 5 seconds and then pulled up. Next, after the formed hollow fiber was dried in still air for 2 hours, the temperature was increased to 350 ° C. at a temperature increase rate of 5 ° C. per minute, and kept at that temperature for 3 hours. did. The pre-electroless plating treatment is performed using a commercially available palladium plating bath (Paratop, Nokogyo Co., Ltd.) having a pH of about 7 under conditions of a plating temperature of 60 ° C. and a plating time of 20 minutes to produce a hydrogen separation composite. A palladium composite film as a raw material was obtained.

(C) (Preparation of hydrogen separation complex)
The palladium composite film subjected to the pre-electroless plating treatment was subjected to the electroless copper plating treatment using the copper plating bath of Example 3 (a) under the conditions of a plating temperature of 60 ° C. and a plating time of 20 minutes. . The obtained palladium-copper multilayer film is dried in still air at 100 ° C. for 3 hours, and then heated to 450 ° C. at a heating rate of 2 ° C. per minute in still air, and held at that temperature for 3 hours. Heat treatment. Next, the temperature was lowered to room temperature at a rate of 5 ° C. per minute to obtain a hydrogen separation complex.

Example 4 (Preparation of hydrogen separation complex)
After removing the polymer layer in this way, the obtained palladium-copper multilayer film was treated in a hydrogen stream at 600 ° C. for 4 hours to give an alloying and reduction treatment, and a hydrogen separation composite ( Palladium-copper composite alloy film) was obtained.
An X-ray diffraction profile of the palladium-copper composite alloy film is shown in FIG. Obviously, a palladium-copper composite alloy film containing no impurity layer was prepared.
The internal structure of the palladium-copper composite alloy film is shown in FIG. It can be seen that a palladium-copper composite alloy layer having a uniform thickness of about 8 μm and having no pinholes was prepared. Moreover, it can be seen that there is no penetration of the palladium-copper composite alloy into the pores of the substrate. Thanks to the smooth and dense surface of the polymer membrane layer, it can be seen that a pinhole and non-penetrated palladium-copper composite alloy film is plated directly onto the macroporous substrate by removing it. . Although the photograph itself is very clear, the photograph in the drawing is not clear because the image conversion process does not proceed smoothly. It can be seen that a space is formed in a horizontal line above (in the upper part of about 2/3 from the bottom) of FIG.

(Test example 7) Relationship between hydrogen permeation flux of palladium-copper composite alloy membrane and hydrogen pressure difference The hydrogen permeation flux of this palladium-copper composite alloy membrane increases with an increase in hydrogen pressure difference, at 400 ° C. With a hydrogen pressure difference of 300 kPa, a high hydrogen permeation flux of 0.48 mol / (s m2) and a high hydrogen / nitrogen separability 1420 were obtained. Moreover, when the operating temperature was increased while maintaining the hydrogen pressure difference, the hydrogen permeation flux increased significantly.

Test Example 8 Stability of Palladium-Copper Composite Alloy Film FIG. 9 shows the hydrogen-He gas exchange frequency dependence of hydrogen and He flux in the palladium-copper composite alloy film. It can be seen that even when the number of cycles is increased, the permeation flux of hydrogen and helium and the hydrogen separability are stable. That is, it can be said that this method is excellent not only for a palladium single film but also for producing a palladium-based alloy film such as a palladium-copper composite alloy film.

Example 5
(A) (Preparation of silver plating bath)
Distilled water was mixed and stirred in 53.5 mg of silver nitrate, 4.0 g of Na2EDTA.2H2O, 20 ml of NH4OH, and 2 ml of formaldehyde to prepare 100 ml of a solution for silver plating.

(B) Preparation of raw material for production of hydrogen separation composite Hollow fiber-shaped α-Al ₂ O ₃ porous material having an inner diameter of 2.2 mm, an outer diameter of 2.9 mm, a film thickness of 350 μm, an average pore diameter of 0.15 μm, and a porosity of 52% The porous substrate was ultrasonically washed with dilute acid, dilute base, ethanol, and distilled water for 5 minutes each at room temperature, and dried in an oven at 100 ° C. for 2 hours. In order to form a thin film layer, the washed hollow fiber-like α-Al ₂ O ₃ porous substrate was dipped in the activation solution of Example 1 (a) for 5 seconds and then rapidly pulled up. Next, after the formed hollow fiber was dried in still air for 2 hours, the temperature was increased to 350 ° C. at a temperature increase rate of 5 ° C. per minute, and kept at that temperature for 3 hours. did. The pre-electroless plating treatment is performed using a commercially available palladium plating bath (Paratop, Okuno Kogyo Co., Ltd.) having a pH of about 7 under the conditions of a plating temperature of 60 ° C. and a plating time of 20 minutes to produce a hydrogen separation composite. A palladium composite film as a raw material was obtained.

(C) (Preparation of hydrogen separation complex)
The palladium composite film subjected to the pre-electroless plating treatment was subjected to the electroless silver plating treatment using the silver plating bath of Example 5 (a) under the conditions of a plating temperature of 60 ° C. and a plating time of 20 minutes. . The obtained palladium-silver multilayer film is dried in still air at 100 ° C. for 3 hours, then heated to 450 ° C. at a heating rate of 2 ° C. per minute in still air, and held at that temperature for 3 hours. Heat treatment. Subsequently, the temperature was lowered to room temperature at a rate of 5 ° C. per minute to obtain a hydrogen separation complex from which the polymer layer was removed.

Example 6 (Preparation of hydrogen separation complex)
By treating the palladium-silver multilayer film at 500 ° C. for 4 hours in a hydrogen stream, alloying and reduction treatment were performed to obtain a hydrogen separation composite (palladium-silver composite alloy film).
From the X-ray diffraction profile of the palladium-silver composite alloy film, a palladium-silver composite alloy film not containing an impurity layer has been prepared. It was found that a silver composite alloy layer was prepared. Moreover, there was no penetration of the palladium-silver composite alloy into the pores of the substrate. Thanks to the smooth and dense polymer membrane layer, the removal of this reveals that a pinhole and non-penetrated palladium-silver composite alloy film is plated directly on the macroporous substrate. It was.

(Test Example 9) Relationship between hydrogen permeation flux of palladium-silver composite alloy membrane and hydrogen pressure difference The hydrogen permeation flux of this palladium-silver composite alloy membrane increases with an increase in the hydrogen pressure difference, at 400 ° C. With a hydrogen pressure difference of 200 kPa, a high hydrogen permeation flux of 0.39 mol / (s m2) and a high hydrogen / He separation property of 700 were obtained. Moreover, when the operating temperature was increased while maintaining the hydrogen pressure difference, the hydrogen permeation flux increased significantly.

(Test Example 10) Stability of palladium-silver composite alloy film Hydrogen permeation flux of hydrogen and He even if the number of cycles is increased from the hydrogen-He gas exchange frequency dependence of hydrogen and He flux of palladium-silver composite alloy film It was also found that hydrogen separability was stable. That is, it can be said that this method is excellent not only for a palladium single film but also for producing a palladium-based alloy film such as a palladium-silver composite alloy film.

Comparative Example 1 (Preparation of production raw material for palladium composite)
A hollow fiber-shaped α-Al ₂ O ₃ porous substrate having an inner diameter of 2.2 mm, an outer diameter of 2.9 mm, a film thickness of 350 μm, an average pore diameter of 0.15 μm, and a porosity of 52% is diluted with dilute acid, dilute base, ethanol, The sample was ultrasonically washed with distilled water at room temperature for 5 minutes each, and dried in an oven at 100 ° C. for 2 hours. In order to form a thin film layer, a washed hollow fiber-like α-Al ₂ O ₃ porous substrate is activated by a conventional method using a commercially available palladium activation solution (Inducer, Christer, Okuno Kogyo Co., Ltd.). Was applied. Next, the activated hollow fiber was dried in still air for 2 hours, and then a commercially available palladium plating bath (paratop, pH 7) under conditions of a plating temperature of 60 ° C. and a plating time of 4 hours. A conventional hydrogen separator (regular palladium composite membrane) was obtained by performing a conventional electroless plating process using a stock trader Okuno Kogyo).

(Test Example 11) Hydrogen Permeation Performance of Conventional Palladium Composite Membrane The hydrogen permeation flux of the palladium composite membrane was as low as 0.06 mol / (sm2) at a hydrogen pressure difference of 200 kPa at 500 ° C. In addition, the hydrogen separability close to infinity obtained in the initial stage of operation had a hydrogen / helium separation factor drastically reduced to several tens of hours after starting the measurement. That is, it can be said that the palladium-based composite membrane produced by electroless plating according to the conventional method tends to be inferior in hydrogen permeability and long-term stability of hydrogen separation as compared with the palladium-based composite membrane according to the present invention.

The present invention can be described as follows.
(1) A laminate comprising at least a porous substrate K, a layer L composed of an easily burnable polymer containing a palladium salt, and an electroless plating layer M composed of palladium or a palladium alloy, and the laminate is heated. A pipe-type hydrogen separator obtained by processing.
(2) A laminate comprising at least a porous substrate K, a layer L made of an easily burnable polymer containing a palladium salt, and an electroless plating layer M made of palladium or a palladium alloy, and the laminate is heated. A pipe-type hydrogen separator obtained by processing. (2) A pipe-type hydrogen separator, wherein an electroless plating layer N made of palladium or a palladium alloy is further formed on the surface of the hydrogen separation membrane of (1).
(3) Step A of forming a layer consisting essentially of an easily burnable polymer containing a palladium salt on the surface of the porous substrate, and laminating an electroless plating layer consisting of at least palladium or a palladium alloy on the surface of the layer And a process for producing a hydrogen separation composite, characterized in that it comprises at least a process B for heating and a process C for heat-treating the laminate to burn away the easily burnable polymer.

(4) A laminate comprising at least a porous substrate and an electroless plating layer made of palladium or a palladium alloy, and characterized in that there is no excessive penetration of the electroless plating layer into the porous substrate. Hydrogen separation complex.
(5) A laminate comprising at least a porous substrate and a layer made of a metal or alloy having a hydrogen separation function, and further penetrating the layer made of a metal or alloy having a hydrogen separation function into the porous substrate. A hydrogen separation complex characterized by being substantially free of hydrogen.
(6) A laminate comprising at least a porous substrate and an electroless plating layer made of palladium or a palladium alloy, and there is substantially no excessive penetration of the electroless plating layer into the porous substrate, A hydrogen separation composite is characterized in that a space layer is substantially retained between the porous substrate and the metal or alloy layer having the hydrogen separation function.
(7) Production of a hydrogen separation composite comprising the step A of forming a layer consisting essentially of an easily burnable polymer containing a metal compound constituting a metal hydrogen separation layer on the surface of a porous substrate In the method, step A forms on the surface of the porous substrate a layer substantially consisting of an easily burnable polymer containing a metal compound that constitutes a hydrogen separation layer comprising a metal, and then in the layer A method for producing a hydrogen separation complex, which is a step of reducing a metal nucleus derived from a metal compound.

It is a photograph which shows the form and structure of the hydrogen separation complex of this invention. The relationship between the hydrogen permeation flux and the hydrogen pressure difference of the palladium composite membrane is shown. The relationship between the hydrogen permeation flux and the operating temperature of the palladium composite membrane is shown. The relationship between the stability of palladium composite membrane and operation time is shown. The stability of hydrogen permeation with respect to the number of hydrogen and helium exchange cycles in a palladium composite membrane is shown. The preparation process of the hydrogen separation complex in this invention is shown. 2 shows an X-ray diffraction profile of a palladium-copper composite alloy film. It is a photograph which shows the structure of the hydrogen separation complex of this invention. The dependence of hydrogen and He flux on the number of hydrogen-He gas exchanges is shown.

Claims (16)

Step A of forming a layer consisting essentially of an easily burnable polymer containing a metal compound constituting the metal hydrogen separation layer on the surface of the porous substrate, the surface of the layer having a hydrogen separation function A method for producing a hydrogen separation complex, comprising at least a step B of laminating a layer made of a metal or an alloy, and a step C of burning out the easily burnable polymer from the laminate. Step A of forming a layer consisting essentially of an easily burnable polymer containing a metal compound constituting the metal hydrogen separation layer on the surface of the porous substrate, the surface of the layer having a hydrogen separation function Step B for laminating a layer made of a metal or alloy, Step C for burning off the easily burnable polymer from the laminate, and a metal or alloy having a hydrogen separation function on the surface of the laminate obtained by the treatment A method for producing a hydrogen separation complex, comprising at least a step D of forming a layer. The method for producing a hydrogen separation complex according to claim 1 or 2, further comprising a step E of heat-treating the substrate on which the layer obtained in the step A is formed. Step A substantially consists of applying and impregnating a porous substrate with a solution composed of a metal compound, a readily burnt-off polymer, and an organic solvent constituting a hydrogen separation layer made of metal. The method for producing a hydrogen separation complex according to any one of claims 1 to 3. 4. The hydrogen separation composite according to claim 1, wherein step B is a step of laminating an electroless plating layer made of a metal or alloy having a hydrogen separation function on the surface of the layer in step A. Body manufacturing method. It is characterized by comprising at least a porous substrate K, a layer L made of an easily burnable polymer containing a metal compound constituting a hydrogen separation layer made of metal, and a layer M made of a metal or alloy having a hydrogen separation function. A laminate for the production of a hydrogen separation complex. The laminate for producing a hydrogen separation composite according to claim 6, wherein the layer M is an electroless plating layer made of a metal or alloy having a hydrogen separation function. A hydrogenated body comprising at least a layer made of a porous substrate and a metal or alloy having a hydrogen separation function, and obtained by heat-treating the laminated body according to claim 6 or 7. Separation complex. 9. A hydrogen separation complex, wherein a layer N made of a metal or alloy having a hydrogen separation function is further formed on the surface of the hydrogen separation complex of claim 8. The hydrogen separation composite according to claim 9, wherein the layer N is an electroless plating layer made of a metal or alloy having a hydrogen separation function. The hydrogen separation complex according to any one of claims 6 to 10, wherein the layer M made of a metal or alloy having a hydrogen separation function has a thickness of 0.5 to 5 µm. The hydrogen separation complex according to claim 9 or 10, wherein the layer N made of a metal or alloy having a hydrogen separation function has a thickness of 0.5 to 10 µm. A laminate comprising at least a porous substrate and a layer made of a metal or alloy having a hydrogen separation function, and the penetration of the layer made of a metal or alloy having a hydrogen separation function into the porous substrate is substantially A hydrogen separation complex characterized by the absence of A laminate comprising at least a porous substrate and a layer made of a metal or alloy having a hydrogen separation function, and between the porous substrate and the layer made of a metal or alloy having a hydrogen separation function A hydrogen separation complex characterized by substantially retaining a space layer. A laminate comprising at least a porous substrate and a layer made of a metal or alloy having a hydrogen separation function, and the penetration of the layer made of a metal or alloy having a hydrogen separation function into the porous substrate is substantially The hydrogen separation composite is characterized in that a space layer is substantially maintained between the porous substrate and the metal or metal alloy layer having a hydrogen separation function. The hydrogen separation complex according to claim 14 or 15, wherein the space layer is a substantially continuous space layer.