JP2012055856A - Metal catalyst carrier, metal catalyst object, and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve a drawback in which in a conventional catalyst carrier which makes a catalyst carrier layer adhere to a metal substrate, there are peeling of a catalyst layer, and carrier unevenness of a catalyst layer.SOLUTION: The metal carrier includes: a metal substrate; and a spongy structure layer made to form on the surface of the metal substrate. The metal carrier is characterized by forming a coating by hydration treatment on the spongy structure layer.

Description

  The present invention relates to a metal catalyst carrier that is a porous body useful for various filters, adsorbents, fillers, and the like, a metal catalyst body, and a method for producing them.

  As conventional metal catalyst bodies, cited references 1 to 7 describe a technique in which an anodized film (alumite film) is formed on the surface of an aluminum substrate and the catalyst is supported in the fine pores formed in the film.

  References 8 to 11 describe a technique in which a catalyst support layer is attached to a metal substrate and a catalyst is supported on the catalyst support layer.

JP 59-59247 A JP-A-2-144154 JP-A-8-246190 JP-A-10-73226 JP 2002-119856 A JP 2007-237090 A JP 2008-126151 A JP-A-8-332394 JP 2007-44574 A Japanese Patent No. 4263268 JP 2008-259968 A

  However, since the catalyst body using the alumite film requires an anodic oxidation treatment, there are disadvantages that the production is not simple and the cost is high.

  Further, the catalyst body in which the catalyst support layer is adhered to the metal substrate has problems of peeling of the catalyst layer, adhesion between the support and the catalyst slurry, and uneven support of the catalyst layer. In order to increase the catalyst activity, it is conceivable to increase the amount of the catalyst. However, if the catalyst layer is made thicker in order to increase the supported amount, the binder component covers the active component and the reactant does not contact the active component. There was a problem that activity could not be obtained than expected.

  The present invention eliminates the above-mentioned drawbacks.

  In the present invention, a catalyst carrier is produced by forming a sponge-like porous body layer having fine pores on the surface of a metal substrate. Alternatively, the metal substrate having the sponge-like structure layer may be hydrated to form a hydrated film on the sponge-like structure layer, and this may be fired to produce a catalyst carrier. Thereafter, a catalyst is loaded to form a catalyst body, and the catalyst body is formed into a metal honeycomb structure, for example.

  Alternatively, after the catalyst carrier is manufactured, it may be formed into a metal honeycomb structure, and then the catalyst may be supported to form a catalyst body. Further, it may be formed into a metal honeycomb structure before or during manufacture of the catalyst carrier.

  The said metal substrate is not specifically limited, It consists of metals, such as aluminum, nickel, a tantalum, copper, and those alloys. Moreover, what formed the said metal layer on the surface of a support body may be used. Further, a clad material may be used.

  The shape of the metal substrate can be selected depending on applications such as foil and wire. Further, a metal honeycomb shape or a pellet shape may be used. Also, the thickness can be freely selected.

  The method for forming the spongy structure layer is not particularly limited, and is performed by an area expansion process such as an electrochemical technique such as an electrochemical etching process or a physical technique such as vapor deposition.

  For example, as shown in FIG. 1, the electrochemical method electrolyzes a metal substrate 1 (including a foil; the same applies hereinafter) such as an aluminum substrate in a solution (for example, hydrochloric acid) bath 2 containing halogen ions by alternating current. Let it be processed. By this electrolytic treatment, corrosion and film formation are alternately repeated on the surface of the metal substrate 1 to form a spongy structure layer in which fine pores are connected.

  The thickness of the spongy structure layer formed on the surface of the metal substrate is not particularly limited, but if the thickness is less than 1 μm, the decomposition activity decreases, and if the thickness is greater than 100 μm, only the pressure loss increases without improving the decomposition activity. A thickness of 1 to 100 μm from the metal surface is preferable.

  Further, if the pore size of the spongy structure layer is too large, the amount of catalyst supported decreases, so the average pore size is 1000 nm at the maximum, and 25 to 300 nm is particularly preferable.

2 shows an SEM photograph of a cross section of the aluminum substrate on which the spongy structure layer is formed, FIG. 3 is a schematic view thereof, 3 is a spongy structure layer, and 4 is a fine hole.

  The hydration treatment is performed to increase the surface area of the metal substrate. For example, when an aluminum substrate is hydrated, a film of aluminum hydroxide is formed on the spongy structure layer, and the hydration solution at this time is not particularly limited. Or it is performed by warm water or hot water. Moreover, you may add triethanolamine, ammonia, sodium silicate, etc. as a reaction accelerator.

  The baking treatment is to dehydrate moisture in the hydrated film and increase the surface area of the metal substrate. For example, when the aluminum substrate is hydrated and fired, if the firing temperature is less than 300 ° C., the alumina is not sufficiently produced, and if the temperature is higher than 550 ° C., the substrate is damaged. Since the surface area is unfavorably lowered, the reaction is performed at 300 to 550 ° C. for 5 minutes to 3 hours.

  The metal having catalytic activity supported on the catalyst carrier is not particularly limited, and examples thereof include known metals, alloys or metal compounds having catalytic activity. For example, platinum metal, platinum metal compound, palladium, rhodium, indium, silver, rhenium, tin, cerium, zirconium, gold, gold alloy, manganese, iron, zinc, copper, nickel, nickel alloy, cobalt, cobalt alloy It is desirable to select from a metal such as ruthenium, a compound such as an oxide or carbonate. Moreover, you may combine these catalyst substances.

  In the method of supporting a catalyst on the catalyst carrier, for example, a metal having catalytic activity is adsorbed on a spongy structure layer or film, and further fixed so as not to be desorbed even when contacted with a substance used for catalytic reaction.

  Specifically, it is not particularly limited, and for example, a known method such as an impregnation method, an electrodeposition method, an ion exchange method, a coprecipitation method, a deposition method, a hydrothermal synthesis method, or a gas phase synthesis method is used. In particular, an impregnation method of immersing in an aqueous solution containing metal ions having catalytic activity is preferable. The aqueous solution used for the impregnation method can be prepared by using a chloride, bromide, ammonium compound, cyanide, alkali metal salt, or a complex compound thereof containing a metal having catalytic activity.

  In addition, a calcination treatment can be performed to fix a metal having catalytic activity.

  In the present invention, a simple, inexpensive and large-area catalyst carrier can be obtained. In addition, the effective amount of catalyst per unit area can be increased, and there is a great advantage that highly efficient and highly durable catalyst activity can be obtained.

  Moreover, in an aluminum base material, adhesiveness with a catalyst is also good.

  In addition, since the hydrated film can be directly applied to the surface of the substrate, the adhesion of the catalyst is good, and there is high activity and high durability.

  In addition, by controlling the thickness of the sponge-like structure layer, the catalyst layer thickness can be designed freely, and the catalyst in the lower layer of the sponge-like structure layer can also be activated, so the amount of effective catalyst per unit area is increased. It becomes possible.

  In addition, since the porous body serving as the catalyst carrier is formed directly on the surface of the metal substrate, the catalyst is supported inside the porous body by an impregnation method or the like, and the adhesion of the catalyst is improved.

  It can also be applied to the treatment of the microreactor wall surface of the microreactor.

It is explanatory drawing of the apparatus used in order to form the sponge-like structure layer of this invention. It is a SEM photograph of the section of the metal substrate which has the spongy structure layer of the present invention. It is a schematic diagram of the metal substrate which has the sponge-like structure layer of this invention.

  The metal catalyst carrier of the present invention comprises a metal substrate and a spongy structure layer formed on the surface of the metal substrate.

  Further, the sponge-like structure layer is formed with a film by hydration treatment.

  Further, the sponge-like structure layer is characterized in that a film baked after being hydrated is formed.

  The method for producing a catalyst carrier of the present invention includes a first step of forming a spongy structure layer on the surface of the metal substrate, a second step of hydrating the metal substrate, and firing the metal substrate. It is characterized by comprising the third step.

  The sponge-like structure layer formed on the surface of the metal substrate has a thickness of 1 to 100 μm.

  The average diameter of the micropores formed in the sponge-like structure layer is 25 to 300 nm.

  A catalyst is supported on the catalyst carrier.

  The catalyst carrier or catalyst body is formed in a metal honeycomb structure.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further in full detail, this invention is not limited by this.

(Comparative Example 1)
Methanol steam reforming catalyst slurry (a mixture of Cu / ZnO catalyst powder and alumina sol binder, flocculant, etc.) was sprayed onto an untreated aluminum foil having a thickness of 25 μm, and fired and fixed.

An aluminum foil having a thickness of 25 μm was electrolyzed in an etching bath temperature of 75 ° C. in a bath of 10 wt% hydrochloric acid + 0.1 wt% sulfuric acid with an alternating current having a frequency of 75 Hz and a current density of 0.6 A / cm ² for 15 seconds. In this case, the thickness of the spongy etching layer was about 5 μm on one side, and the average fine pore diameter was about 50 nm. Then, this etched aluminum foil was hydrated in ion exchange water at 80 ° C. for 1 hour. The aluminum foil subjected to this etching treatment and hydration treatment was immersed in a solution in which copper and zinc ions were dissolved, and copper and zinc were supported to obtain a catalyst body. In this case, the catalyst loading was 1.0 g / m ² .

A catalyst body was obtained in the same manner as in Example 1 except that an aluminum foil having a thickness of 50 μm was used. In this case, the catalyst loading was 1.0 g / m ² .

An aluminum foil having a thickness of 50 μm was electrolyzed in an etching bath temperature of 75 ° C. and a 10 wt% hydrochloric acid + 0.1 wt% sulfuric acid bath at an alternating current with a frequency of 100 Hz and a current density of 0.6 A / cm ² for 30 seconds. In this case, the thickness of the spongy etching layer was about 10 μm on one side, and the average fine pore diameter was about 25 nm. Thereafter, the same operation as in Experimental Example 1 was performed to obtain a catalyst body. In this case, the catalyst loading was 2.1 g / m ² .

An aluminum foil having a thickness of 50 μm was electrolyzed with an alternating current having a frequency of 75 Hz and a current density of 0.6 A / cm ^{2 in} an etching bath temperature of 75 ° C., 10 wt% hydrochloric acid + 0.1 wt% sulfuric acid for 30 seconds. In this case, the thickness of the spongy etching layer was about 10 μm on one side, and the average fine pore diameter was about 50 nm. Thereafter, the same operation as in Experimental Example 1 was performed to obtain a catalyst body. In this case, the amount of catalyst supported was 2.0 g / m ² .

An aluminum foil having a thickness of 50 μm was electrolyzed with an alternating current having a frequency of 10 Hz and a current density of 0.6 A / cm ^{2 in} an etching bath temperature of 75 ° C., 10 wt% hydrochloric acid + 0.1 wt% sulfuric acid for 30 seconds. In this case, the thickness of the spongy etching layer was about 10 μm on one side, and the average fine pore diameter was about 300 nm. Thereafter, the same operation as in Experimental Example 1 was performed to obtain a catalyst body. In this case, the amount of catalyst supported was 1.6 g / m ² .

An aluminum foil having a thickness of 50 μm was electrolyzed with an alternating current having a frequency of 8 Hz and a current density of 0.6 A / cm ^{2 in} an etching bath temperature of 75 ° C., 10 wt% hydrochloric acid + 0.1 wt% sulfuric acid for 30 seconds. In this case, the thickness of the spongy etching layer was about 10 μm on one side, and the average fine pore diameter was about 400 nm. Thereafter, the same operation as in Experimental Example 1 was performed to obtain a catalyst body. In this case, the catalyst loading was 1.0 g / m ² .

An aluminum foil having a thickness of 50 μm was electrolyzed in an etching bath temperature of 75 ° C. in a 10 wt% hydrochloric acid + 0.1 wt% sulfuric acid bath at an alternating current with a frequency of 75 Hz and a current density of 0.6 A / cm ² for 45 seconds. In this case, the thickness of the spongy etching layer was about 15 μm on one side, and the average fine pore diameter was about 50 nm. Thereafter, the same operation as in Experimental Example 1 was performed to obtain a catalyst body. In this case, the amount of catalyst supported was 3.0 g / m ² .

An aluminum foil having a thickness of 50 μm was electrolyzed in an etching bath temperature of 75 ° C. in a 10 wt% hydrochloric acid + 0.1 wt% sulfuric acid bath at an alternating current having a frequency of 75 Hz and a current density of 0.6 A / cm ² for 60 seconds. In this case, the thickness of the spongy etching layer was about 20 μm on one side, and the average fine pore diameter was about 50 nm. Thereafter, the same operation as in Experimental Example 1 was performed to obtain a catalyst body. In this case, the amount of catalyst supported was 4.0 g / m ² .

An aluminum foil having a thickness of 100 μm was electrolyzed in an etching bath temperature of 75 ° C. in a bath of 10 wt% hydrochloric acid + 0.1 wt% sulfuric acid with an alternating current having a frequency of 75 Hz and a current density of 0.6 A / cm ² for 120 seconds. In this case, the thickness of the spongy etching layer was about 40 μm on one side, and the average fine pore diameter was about 50 nm. Thereafter, the same operation as in Experimental Example 1 was performed to obtain a catalyst body. In this case, the amount of catalyst supported was 8.0 g / m ² .

An aluminum foil having a thickness of 200 μm was electrolyzed in an etching bath temperature of 75 ° C. in a bath of 10 wt% hydrochloric acid + 0.1 wt% sulfuric acid at an alternating current of a frequency of 75 Hz and a current density of 0.6 A / cm ² for 240 seconds. In this case, the thickness of the spongy etching layer was about 80 μm on one side, and the average fine pore diameter was about 50 nm. Thereafter, the same operation as in Experimental Example 1 was performed to obtain a catalyst body. In this case, the catalyst loading was 15.0 g / m ² .

  For the evaluation of catalyst activity, taking advantage of the high specific surface area as a feature of the catalyst carrier according to the present invention, the steam reforming of methanol is carried out with a view to application to small reformers for fuel cells that are expected to grow in the future. Performed and evaluated.

A catalyst body prepared in a foil shape was cut out into a stainless steel cylindrical reaction tube, inserted, and the reforming reaction temperature was heated to 300 ° C. in an electric furnace. A mixed gas of methanol and water vapor was introduced at a constant amount with respect to the catalyst amount, and the reformed gas was analyzed and evaluated.
The decomposition measurement data is shown in Table 1.

  As a result, it was found that the metal catalyst body having the sponge structure layer of the present invention has excellent performance.

1 Aluminum substrate 2 Bath 3 Sponge-like structure layer 4 Micropores

Claims (13)

  A metal catalyst carrier comprising a metal substrate and a spongy structure layer formed on the surface of the metal substrate.   The metal catalyst carrier according to claim 1, wherein the sponge-like structure layer formed on the surface of the metal substrate has a thickness of 1 to 100 µm.   The metal catalyst carrier according to claim 1 or 2, wherein an average diameter of the fine pores formed in the sponge-like structure layer is 25 to 300 nm.   The metal catalyst carrier according to claim 1, 2 or 3, wherein a film by hydration treatment is formed on the sponge-like structure layer.   The metal catalyst carrier according to claim 1, 2 or 3, wherein the sponge-like structure layer is formed with a film baked after being hydrated.   A metal catalyst body in which a catalyst is supported on the catalyst carrier according to any one of claims 1, 2, 3, 4 and 5.   A metal catalyst body, wherein the catalyst carrier according to any one of claims 1, 2, 3, 4 and 5 is formed in a metal honeycomb structure, and a catalyst is supported on the catalyst carrier. A first step of forming a spongy structure layer on the surface of the metal substrate;
A second step of hydrating the metal substrate;
A method for producing a metal catalyst carrier, comprising a third step of firing the metal substrate.   9. The method for producing a metal catalyst carrier according to claim 8, wherein the sponge-like structure layer formed on the surface of the metal substrate has a thickness of 1 to 100 [mu] m.   The method for producing a metal catalyst carrier according to claim 8 or 9, wherein the average diameter of the micropores formed in the sponge-like structure layer is 25 to 300 nm.   A method for producing a metal catalyst body, further comprising a step of supporting a catalyst on the catalyst carrier according to any one of claims 8, 9 and 10. Forming the catalyst carrier according to claim 8, 9 or 10 into a metal honeycomb structure;
A method for producing a metal catalyst body, further comprising a step of supporting the catalyst on the catalyst carrier. A step of supporting a catalyst on the catalyst carrier according to claim 8, 9 or 10 to produce a catalyst body;
And a step of forming the catalyst body into a metal honeycomb structure.

Images