JP2010142699A - Method for producing exhaust gas catalyst by using coaxial vacuum arc vapor deposition source - Google Patents

Abstract

Provided is a method for supporting nanoparticles for exhaust gas catalyst and a method for producing exhaust gas catalyst.
A coaxial vacuum arc deposition source 1 is used to apply a pulse voltage between a trigger electrode 13 and a cathode 12 in a vacuum atmosphere to generate a trigger discharge, and between the cathode 12 and the anode 11. A capacitor and a DC power source are connected, a DC discharge voltage of 60 to 100 V is applied with a capacitor capacity of 360 μF or more and 1080 μF or less to intermittently induce arc discharge, and the generated catalytic metal charged particles are supported on the carrier. Is supplied to the surface of the alumina powder mixed with an oxide of a metal consisting of alumina powder, zirconium, or lanthanoid, and vapor-deposited to obtain a catalyst comprising a carrier on which catalytic metal nanoparticles are supported.
[Selection] Figure 3

Description

  The present invention relates to a method for producing an exhaust gas catalyst using a coaxial vacuum arc deposition source, and more particularly to a method for producing an exhaust gas catalyst that provides a catalyst capable of treating exhaust gas from an internal combustion engine such as an automobile, a motorcycle, or a boiler.

From the viewpoint of environmental pollution, exhaust gas from automobiles and the like has become a major social problem, and many technologies relating to the treatment of this exhaust gas have been proposed. There are three types of exhaust gas from automobiles: CH gas, CO gas, and NO _x gas, and these gases are decomposed and detoxified using various exhaust gas catalysts. .

Conventional exhaust gas catalysts are mainly manufactured by a wet method. For example, as shown in FIG. 1, first, platinum of a bullion is pulverized into a powder, and this powder is dissolved in a solvent (for example, hydrochloric acid) to form a water-soluble platinum salt (for example, chloroplatinic acid). Alumina (Al ₂ O ₃ ) powder is added to this chloroplatinic acid and stirred to prepare a slurry in which platinum-supported alumina powder is suspended, and the resulting slurry is applied to a honeycomb-shaped substrate (carrier body). An exhaust gas catalyst in which platinum is supported on a substrate is manufactured (for example, see Patent Document 1).

  In addition, it has been proposed to manufacture a gas purification material that functions as a decomposition catalyst and / or an adsorbent for toxic gases using a laser ablation method that is a dry film formation method (see, for example, Patent Document 2).

JP-A-9-149102 (Claims etc.) JP 2005-125259 A (Claims)

  In the step of supporting platinum on alumina powder by the above-described wet method, platinum loss occurs when the platinum metal is pulverized into powder, and the platinum powder is dissolved in a solvent to form a water-soluble salt. Loss of platinum also occurs when using chloroplatinic acid. Furthermore, platinum loss occurs when an alumina powder is added to the chloroplatinic acid to support the platinum on the alumina powder to prepare a slurry in which the platinum-supported alumina powder is suspended. Thus, there is a problem that the loss of platinum is large and the function of the obtained catalyst is not always satisfactory. Further, the catalyst supported by the wet method has a problem that the function of the decomposition reaction in a high temperature region is lowered.

  Further, the purification material obtained by the laser ablation method which is a dry method has a problem that the function of the decomposition reaction in a high temperature region (400 ° C. or higher) is not always satisfactory.

  Accordingly, an object of the present invention is to solve the above-described problems of the prior art, and to provide a method for manufacturing an exhaust gas catalyst using a coaxial vacuum arc evaporation source.

  In the method for producing an exhaust gas catalyst of the present invention, a cylindrical trigger electrode and a columnar cathode having an evaporation material member made of a catalytic metal material are fixed coaxially adjacent to each other through a cylindrical insulator. In a vacuum atmosphere, using a vapor deposition apparatus comprising a vacuum chamber having a coaxial vacuum arc vapor deposition source disposed coaxially around the columnar cathode with a cylindrical anode spaced apart, A pulse voltage is applied between the trigger electrode and the cathode to generate a trigger discharge, a capacitor and a DC power source are connected between the cathode and the anode, and a capacitor capacity of 360 μF to 1080 μF is used. A DC discharge voltage of 100 V is applied to intermittently induce arc discharge, and charged particles generated from the evaporating material member are released into the vacuum chamber. The particles are supplied and vapor-deposited on the surface of alumina powder mixed with alumina powder, zirconium or lanthanoid metal oxide as a carrier placed in a container placed in the vacuum chamber, and the catalyst A catalyst comprising a carrier on which metal nanoparticles are supported is formed.

  When the capacitance is less than 360 μF, nanoparticles are hardly formed, and when the capacitance exceeds 1080 μF, the particle size of the nanoparticles becomes non-uniform. When the discharge voltage is less than 60V, the discharge is difficult to reach, and when it exceeds 100V, the particle size of the nanoparticles becomes non-uniform.

  By using a coaxial vacuum arc deposition source, it becomes possible to produce a metal nanoparticle-supported catalyst that is highly active in a high temperature region.

  In the method for producing an exhaust gas catalyst, the catalytic metal material is at least one metal selected from palladium (Pd), platinum (Pt), cobalt (Co), silver (Ag), and rhodium (Rh), or these An alloy composed of two or more kinds of metals is preferable.

  According to the present invention, it is possible to produce an exhaust gas catalyst having a high activity in a high temperature region in which catalytic metal nanoparticles are supported on a carrier by using a coaxial vacuum arc deposition source.

According to the embodiment of the method for producing an exhaust gas catalyst according to the present invention, the cylindrical trigger electrode and the columnar cathode having the evaporation material member made of palladium are coaxially arranged through the cylindrical insulator. Using a vapor deposition apparatus consisting of a vacuum chamber provided with a coaxial vacuum arc vapor deposition source, which is arranged adjacently fixed and coaxially arranged around the columnar cathode and spaced apart by a cylindrical anode, A pulse voltage is applied between the trigger electrode and the cathode to generate a trigger discharge in a vacuum atmosphere of 1 to 10 ⁻⁵ Pa without heating the carrier with a heat source, and between the cathode and the anode. A capacitor and a DC power source are connected, and a DC discharge voltage of 60 to 100 V is applied with a capacitor capacity of 360 μF or more and 1080 μF or less to induce arc discharge intermittently. The charged particles generated from um to release into the vacuum chamber, the charged particles, wherein were placed in placing the container in a vacuum chamber, than alumina alumina powder or La ₂ O ₃ or the like as a carrier An exhaust gas catalyst comprising a carrier on which palladium nanoparticles are supported can be formed by supplying the metal oxide to the surface of an alumina powder mixed with a small amount of the metal oxide and depositing it.

The exhaust gas catalyst thus obtained is a metal nanoparticle-supported catalyst that is highly active in a high temperature region, and can decompose and detoxify the exhaust gas of CH gas, CO gas, and NO _x gas.

  As the catalytic metal material constituting the evaporating material member, in addition to Pd, for example, at least one metal selected from Pt, Co, Ag, Rh, etc., and an alloy composed of two or more of these metals, etc. Can be mentioned.

Examples of the carrier include zirconia, magnesia, titania, ceria, silica, and the like in addition to the alumina powder, and examples of the metal oxide mixed in the alumina powder include ZrO ₂ and La ₂ O ₃ . Examples thereof include CeO ₂ and Yb ₂ O ₃ . If the amount of the metal oxide mixed into the alumina powder or the like is, for example, 97% by weight of alumina and 3% by weight of metal oxide, desired metal nanoparticles having excellent catalytic activity can be produced.

  The coaxial vacuum arc deposition source that can be used in the present invention is not particularly limited. For example, ARL-300 manufactured by ULVAC, Inc. can be used.

  A configuration example of a vapor deposition apparatus including a vacuum chamber provided with a coaxial vacuum arc vapor deposition source used in the present invention will be described below with reference to FIG.

  The cathode 12 has a cylindrical shape, and may be entirely composed of the catalytic metal material as described above, or one end may be composed of these catalytic metal materials and the other end may be composed of a rod-shaped electrode. . The cathode 12 is preferably placed facing the carrier so that the catalytic metal material can be released into the vacuum chamber 2 and supplied to the carrier surface, which is the substrate to be treated. The cathode 12 is inserted in close contact with a cylindrical trigger electrode 13 and a cylindrical insulator (hereinafter referred to as a hat-type insulator) 14.

  Thus, the coaxial vacuum arc vapor deposition source used in the present invention is arranged such that the cylindrical trigger electrode 13 and the columnar cathode 12 are coaxially adjacently fixed via the cylindrical hat-type insulator 14, A cylindrical anode 11 is coaxially arranged around the columnar cathode 12 so as to be spaced apart.

  The hat-type insulator 14 is disposed between the cathode 12 and the trigger electrode 13, and the cathode 12, the hat-type insulator 14, and the trigger electrode 13 are arranged in this order from the center. The three parts of the cathode 12, the hat-type insulator 14, and the trigger electrode 13 are in close contact with each other and are attached in close contact with and fixed by screws or the like (not shown). The material of the anode 11 and the trigger electrode 13 is, for example, stainless steel, and the material of the hat-type insulator is, for example, alumina.

  The anode 11, the trigger electrode 13, and the cathode 12 are insulated from each other, and an arc power source having a DC power source 15 a and a capacitor unit 15 b is connected between the cathode 12 and the anode 11. The trigger power supply 16 is connected to the electrodes 11 and 12 so that different voltages can be applied. The capacitor unit 15b is a unit formed by connecting a plurality of capacitors in parallel. Although one capacitor is shown in FIG. 2, the number of capacitors can be appropriately increased or decreased according to the application. For example, if five capacitors each having a capacitance of 360 μF (withstand voltage: 400 V) are connected in parallel, the capacitance is 1800 μF, and if three capacitors are connected in parallel, the capacitance can be used as 1080 μF. In addition, four capacitors of 2200 μF (withstand voltage of 100 V) can be connected in parallel and used as a capacity of 8800 μF.

  Each end of the capacitor unit 15b is connected to the anode 11 and the cathode 12, respectively, and the capacitor unit 15b and the DC power supply 15a are connected in parallel. The DC power supply 15a is, for example, a power supply capable of flowing a current of several A at 100V, and is configured to charge the capacitor unit 15b with a constant charging time.

  The trigger power supply 16 is composed of a pulse transformer, and is configured so that a pulse voltage of 200 μs of input voltage is transformed to about 17 times and output at 3.4 kV (several μA), polarity: positive, and transformed. The voltage is connected so as to be applied to the trigger electrode 13 having a positive polarity with respect to the cathode 12. That is, the positive output terminal of the trigger power supply 16 is connected to the trigger electrode 13, and the negative terminal thereof is connected to the same potential as the negative output side terminal of the arc power supply (DC power supply 15a) and connected to the cathode 12. . A positive terminal of the DC power supply 15 a is grounded to the ground potential and connected to the anode 11. Further, both terminals of the capacitor unit are connected between the positive and negative terminals of the DC power supply 15a.

  The coaxial vacuum arc deposition source 1 configured as described above is attached to the wall surface of a vacuum chamber 2 having a predetermined vacuum exhaust system (for example, a turbo molecular pump and a rotary pump), Used to form the exhaust gas catalyst of the present invention. One or more coaxial vacuum arc deposition sources 1 can be installed as appropriate. The anode 11 and the vacuum chamber 2 are connected to the ground potential.

  In the vacuum chamber 2, a stage 23 is placed opposite to the coaxial vacuum arc vapor deposition source 1 to place a stirring vessel 22 for storing a carrier powder 21. The stirring vessel 22 is provided with means for uniformly stirring the powder 21 of the carrier contained therein. That is, in FIG. 2, the stirring vessel 22 includes a fixed blade 24 for stirring, and a rotation mechanism 25 for making the stage and thus the stirring vessel rotatable is connected to the center of the lower surface of the stage 23. The rotating container 25 is used to rotate the stirring container 22, and the stationary blade 24 is configured to uniformly stir the carrier powder 21. In this case, a means for uniformly stirring the carrier powder 21 in the stirring vessel 22 may be provided. For example, the stirring vessel 22 may be fixed and stirred by the stirring means.

Further, a vacuum exhaust system including a valve 26a, a turbo molecular pump 26b, a valve 26c, and a rotary pump 26d is connected to the wall surface of the vacuum chamber 2 in this order by a metal pipe. By this evacuation system, the inside of the vacuum chamber 2 is evacuated, and the inside of the chamber can be maintained at 10 ⁻⁵ Pa or less.

  The coaxial vacuum arc vapor deposition source described above is known to have higher energy of particles than the sputtering method, and has a feature that there are few impurities because it is a vapor deposition treatment in a vacuum atmosphere.

According to the present invention, the charged particles of the catalytic metal material generated by the operation of the coaxial vacuum arc deposition source 1 are discharged into the vacuum chamber 2 in which a predetermined vacuum atmosphere is formed, and the vacuum chamber is discharged. The catalyst metal nanoparticles are vapor-deposited on the surface of the carrier.
Hereinafter, an operation example of the coaxial vacuum arc deposition source 1 used in the present invention will be described.

  First, the capacitance of the capacitor unit 15 b is set to 360 μF or more and 1080 μF or less, a voltage of 60 to 100 V is output from the DC power supply 15 a, the capacitor unit 15 b is charged with the voltage, and the capacitor unit 15 is connected between the anode 11 and the cathode 12. A charging voltage of 15b is applied. A negative voltage output from the capacitor unit 15b is applied to an evaporating material member made of a catalytic metal material.

  When a pulsed trigger voltage of 3.4 kV is output from the trigger power supply 16 with the voltage applied as described above and applied between the cathode 12 and the trigger electrode 13, trigger discharge (at the surface of the hat-type insulator 14 ( Creeping discharge) occurs. Electrons are emitted from the joint between the cathode 12 and the hat insulator 14.

  With this trigger discharge, the withstand voltage between the anode 11 and the cathode 12 decreases, and arc discharge is induced between the inner peripheral surface of the anode 11 and the outer peripheral surface (side surface) of the cathode 12.

  Due to the discharge of the electric charge charged in the capacitor unit 15b, an arc current having a peak current of 1800 A or more flows for a time of about 200 μsec, and a large amount is generated on the central axis of the cathode 12 (that is, a catalytic metal material which is an evaporation material member). Current (2000 A to 5000 A) flows for 200 μs to 550 μs, so that a magnetic field is formed in the vicinity of the cathode, and a metal plasma is formed by the metal vapor released from the side surface into the vacuum chamber 2. Electrons in the plasma generated at this time (the electrons fly from the cathode to the inner cylindrical surface of the anode) receive a Lorentz force in the direction opposite to the direction in which the current flows by the self-generated magnetic field, fly forward, On the other hand, the catalyst metal ions constituting the cathode in the plasma fly forward as the electrons fly and polarize as described above and are attracted to the forward electrons by Coulomb force. Then, it is discharged into the vacuum chamber 2 from the discharge port 11 a of the anode 11 facing the stage 23.

  An arc discharge is induced once by one trigger discharge, and an arc current flows for 300 μs. When the charging time of the capacitor unit 15b is about 1 second, arc discharge can be induced with a period of 1 Hz. Arc discharge is induced a predetermined number of times, and the catalytic metal nanoparticles are supported on the surface of the support with a predetermined number of shots (number of shots).

  As described above, it has been explained that if a coaxial vacuum arc deposition source is used, the catalytic metal nanoparticles can be formed without heating the carrier with a heat source which is a heating means such as a heater. Even when the support is used, catalytic metal nanoparticles can be supported in the same manner as in the case of carrying out without heating.

  In FIG. 2, a mass flow meter 27 a, a valve 27 b, and a gas cylinder 27 c are provided for cases where it is necessary to introduce gas into the vacuum chamber 2.

Hereinafter, the present invention will be described in detail with reference to examples and comparative examples. In the following examples and comparative examples, Pt was used as the catalyst metal material, alumina powder + La ₂ O ₃ powder was used as the support, and Pt nanoparticles were deposited on the surface of the support particles. An exhaust gas catalyst having excellent catalytic activity can be formed using the coaxial vacuum arc deposition source in the same manner with the above-described other catalytic metal materials and other carrier / carrier blend amounts. The discharge conditions are not limited to those described in the examples, and the discharge conditions may be in a range in which metal nanoparticles can be similarly formed using a coaxial vacuum arc deposition source, and are limited to the conditions described in the following examples. Not.

As a vapor deposition apparatus equipped with a coaxial vacuum arc vapor deposition source (manufactured by ULVAC, Inc .: ARL-300), an apparatus schematically shown in FIG. 2 is used, and La ₂ O _{3 is} added to 97 wt% of alumina (Al ₂ O ₃ ) powder. 4 g of the carrier added with 3 wt% of powder was used, and 0.2 wt% of Pt nanoparticles were supported on the surface of the particles of the carrier as described below.

That is, as a parameter, a trigger voltage is generated by outputting a 3.4 kV pulsed trigger voltage from the trigger power supply 16 under the conditions of a capacity of the capacitor unit 15b: 1080 μF, a discharge voltage: 100 V, and a frequency: 4 Hz. Arc discharge induced by the trigger discharge is performed a predetermined number of times, and the support powder 21 accommodated in the stirring vessel 22 is uniformly stirred at a predetermined number of shots (4850 shots) while the Pt nano-particles are formed on the surface of the support. Particles (particle size 2-3 nm) were deposited and formed. The exhaust gas catalyst thus obtained had a composition of 0.2 Pt / La ₂ O ₃ —Al ₂ O ₃ in which 0.2 wt% of Pt nanoparticles were supported on the support surface.

Next, 0.05 g of Pt-supported exhaust gas catalyst produced as described above was placed in this apparatus using a flow reactor, and 0.05% NO, 0% was added to this catalyst. _{.51% CO, 0.0394% C 3} H 6, 0.4% O 2, the gas and the balance He (three-way catalyst evaluation gas gasoline vehicles) at a flow rate 100mL / min (W / F = 5 0.000 × 10 ⁻⁴ g · min · cm ⁻³ ), while raising the catalyst temperature to 600 ° C. (10 ° C./min), the catalytic activity is determined from the reaction rate (%) at each temperature, which is the temperature raising reaction characteristic. evaluated. In this case, the Pt-supported catalyst itself produced as described above (high-temperature steam untreated) and Pt obtained by carrying out the high-temperature steam treatment (900 ° C., 25 hours, 10% H ₂ O / air) after loading. The supported catalyst was evaluated.

  The obtained results are plotted in FIG. 3A and FIG. 4A with the reaction temperature (° C.) on the horizontal axis and the reaction rate (%) on the vertical axis. FIG. 3A shows the result when high-temperature steam is not treated, and FIG. 4A shows the result when high-temperature steam is treated. In FIGS. 3A and 4A, APG (arc plasma gun) shows a case where Pt is carried using coaxial vacuum arc deposition.

The method described in Example 1 was repeated using Pd instead of Pt in Example 1. As a result, a catalyst having a composition of 0.2 Pd / La ₂ O ₃ —Al ₂ O ₃ was obtained, and the catalytic activity was almost the same as in Example 1.

(Comparative Example 1)
Pt (NH ₃ ) ₂ (NO ₂ ) ₂ was used as a supported catalyst raw material, and Pt was wet impregnated and supported on a La ₂ O ₃ —Al ₂ O ₃ support. That is, a La ₂ O ₃ —Al ₂ O ₃ carrier powder is impregnated with a predetermined amount of an aqueous solution of Pt (NH ₃ ) ₂ (NO ₂ ) ₂ having a predetermined concentration, and then evaporated to dryness, followed by baking at 600 ° C. for a predetermined time. Then, Pt was supported, and a Pt-supported catalyst having a composition of 0.2 Pt / La ₂ O ₃ —Al ₂ O ₃ was prepared. The catalytic activity of the Pt-supported catalyst as obtained and the Pt-supported catalyst obtained by carrying out high-temperature steam treatment in the same manner as in Example 1 after the support was evaluated according to the method described in Example 1.

  The obtained results are plotted in FIG. 3B and FIG. 4B, with the reaction temperature (° C.) on the horizontal axis and the reaction rate (%) on the vertical axis. FIG. 3 (b) shows the results when the high-temperature steam is not treated, and FIG. 4 (b) shows the results when the high-temperature steam is treated.

  Comparing the results of FIGS. 3 (a) and 3 (b), when high-temperature steam treatment was not performed after Pt support, the support with the coaxial vacuum arc deposition source was performed at a lower temperature than the support with the wet method. It is easy to react and it turns out that it is highly active. For example, when supported by a coaxial vacuum arc deposition source, for all gas components, the reaction rate is around 10% at 300 ° C, the reaction rate is around 80% at 400 ° C in the high temperature region, and further at 500 ° C. While the reaction rate is almost 100%, when supported by a wet method, the reaction rate is 0% at 300 ° C. and the reaction rate is 20% at 400 ° C. in the high temperature range for all gas components. It can be seen that the reaction rate is almost 80% even at 500 ° C.

  4 (a) and 4 (b), when high-temperature steam treatment is performed after supporting Pt, the temperature supported by the coaxial vacuum arc deposition source is lower than that supported by the wet method. It turns out that it is easy to react. When supported by a coaxial vacuum arc deposition source, the catalytic activity is deteriorated compared to the case where high-temperature steam treatment is not performed, but for all gas components, the temperature is higher than when supported by a wet method. It is highly active even in the region (400 ° C. or higher). On the other hand, when it is supported by a wet method, the reaction start temperature is increased by high-temperature steam treatment, the catalytic activity is deteriorated, and the reaction rate is low at around 10% even at 400 ° C. for all gas components. In order to obtain the same reaction rate as compared with the case where it was supported by a mold type vacuum arc vapor deposition source, it was necessary to be at a high temperature, and the reaction rate was 80% or less even at 600 ° C.

(Comparative Example 2)
In accordance with the laser ablation method described in JP-A-2005-125259, Pt was supported on the surface of the carrier to produce a gas purification material.

That is, a slurry was prepared from a La ₂ O ₃ —Al ₂ O ₃ carrier and distilled water according to the method of the examples described in JP-A-2005-125259. The obtained slurry was applied to the surface of the honeycomb plate, dried at 120 ° C. for 3 hours, and further fired in an air stream at 450 ° C. for 2 hours to obtain a metal oxide carrier. Using the metal oxide support thus obtained, a YAG laser light source, a platinum plate as a target, a target and a carrier are rotated at a predetermined number of revolutions under a vacuum, and the laser light source is used. The target was irradiated with pulsed laser light for 60 seconds under the conditions described above. As a result, a platinum thin film made of platinum fine particles was formed on the surface of the carrier. The platinum-supported catalyst was subjected to hydrogen reduction treatment at 500 ° C. for 2 hours in a mixed gas of hydrogen and nitrogen (hydrogen content: 5% by volume) to produce a Pt-supported catalyst.

  The catalytic activity of the Pt-supported catalyst thus obtained was evaluated according to the method described in Example 1. The obtained results were almost the same as in the wet method of Comparative Example 1.

  In this example, the Pt-supported catalyst was prepared by repeating the method described in Example 1 except that the capacity of the capacitor unit 15b was set to 360 μF, 720 μF, and 1440 μF and the discharge voltage was set to 60 V and 150 V.

  The catalytic activity of the Pt-supported catalyst thus obtained was evaluated according to the method described in Example 1. As a result, in the case of 360 μF, 720 μF, and 60 V, the same tendency as in Example 1 was obtained, but in the case of 1440 μF and 150 V, the catalytic activity was inferior to that in Example 1.

  According to the present invention, by using a coaxial vacuum arc deposition source, a metal nanoparticle-supported catalyst that is highly active in a high temperature region can be provided. Therefore, the present invention is particularly effective for exhaust gas from internal combustion engines such as automobiles, motorcycles, and boilers. Can be used in the field of catalyst technology.

Process drawing for demonstrating the process of preparing an exhaust gas catalyst by a wet method. The block diagram which shows typically the example of 1 structure of the vapor deposition apparatus provided with the coaxial type vacuum arc vapor deposition source used by this invention. It is a graph which shows the catalyst activity of Pt carrying | support catalyst itself manufactured according to Example 1 and Comparative Example 1 (high temperature steam untreated), (a) shows the case where Pt is carried by a coaxial vacuum arc evaporation source, (B) shows the case where Pt is supported by a wet method. It is a graph which shows the catalytic activity of the Pt carrying | support catalyst manufactured according to Example 1 and the comparative example 1 (high temperature steam treatment), (a) shows the case where Pt is carry | supported with a coaxial type vacuum arc evaporation source, (b ) Shows a case where Pt is supported by a wet method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coaxial type vacuum arc evaporation source 2 Vacuum chamber 11 Anode 11a Emission port 12 Cathode 13 Trigger electrode 14 Hat type insulator 15a DC power supply 15b Capacitor unit 16 Trigger power supply 21 Powder of carrier 22 Stirring vessel 23 Stage 24 Fixed blade 25 Rotating mechanism 26a, 26c Valve 26b Turbo molecular pump 26d Rotary pump 27a Mass flow meter 27b Valve 27c Gas cylinder

Claims (2)

A cylindrical trigger electrode and a columnar cathode having an evaporating material member made of a catalytic metal material are disposed adjacently and coaxially through a cylindrical insulator, and the columnar cathode Using a vapor deposition apparatus comprising a vacuum chamber having a coaxial vacuum arc vapor deposition source in which a cylindrical anode is coaxially arranged and spaced apart, a pulse is generated between the trigger electrode and the cathode in a vacuum atmosphere. A voltage is applied to generate a trigger discharge, a capacitor and a DC power source are connected between the cathode and the anode, and a DC discharge voltage of 60 to 100 V is applied intermittently with a capacitor capacity of 360 μF to 1080 μF. An arc discharge is induced to discharge charged particles generated from the evaporation material member into the vacuum chamber, and the charged particles are placed in the vacuum chamber. It is made of a carrier on which catalytic metal nanoparticles are supported by supplying it to the surface of alumina powder mixed with an oxide of alumina powder, zirconium, or a metal oxide consisting of lanthanoid as a carrier placed in the container. A method for producing an exhaust gas catalyst, comprising forming a catalyst. The method for producing an exhaust gas catalyst according to claim 1, wherein the catalytic metal material is at least one metal selected from Pd, Pt, Co, Ag, and Rh, or an alloy composed of two or more of these metals. A method for producing an exhaust gas catalyst.

Images