JP2019181462A - Catalyst filter - Google Patents

Abstract

To provide a novel technique that can improve catalytic activity in a catalyst filter.SOLUTION: A catalyst filter has: a gold catalyst containing a support composed of an acidic, solid metal oxide, and a gold particle supported on the support; and a filter base material having the gold catalyst supported on its surface. With respect to the surface of the filter base material, an amount of the supported gold particles is 0.005 g/mor more and 0.5 g/mor less.SELECTED DRAWING: None

Description

  The present invention relates to a catalytic filter that can oxidatively decompose carbon monoxide and the like.

  Since exhaust gas generated from internal combustion engines such as automobiles and factories contains trace amounts of harmful components such as carbon monoxide, they are released into the atmosphere after they are removed using removal means. In addition, in a closed storage room or the like, a trace amount of malodorous substances may be produced and ammonia odor may be generated, and various removal means are applied.

  As a method for removing harmful components, adsorption to an adsorbent such as activated carbon, radicals using a plasma generator, and decomposition and removal methods using active species such as ozone are widely used. However, in the adsorption treatment with the adsorbent, there is an upper limit on the amount of harmful component adsorbed by the adsorbent, and periodic replacement of the adsorbent is necessary.

As a method of decomposing and removing harmful components, a method of oxidizing and decomposing using a catalyst is widely used in addition to a method of oxidizing and decomposing with physically generated active species such as the plasma method described above. Yes. As an oxidation catalyst body, a structure in which an active substance (catalyst particles) is supported on a carrier that is inorganic particles is used in order to increase the contact area (Patent Document 1). Further, a catalyst body in which catalyst particles are supported in the pores of an inorganic mesoporous carrier having cylindrical mesopores has been developed (Patent Documents 2 and 3).
In addition, the present inventors have proposed a removal method in which a plasma generator and a metal fine particle catalyst are combined (Patent Document 4).

Japanese Patent Laid-Open No. 2003-080077 JP 2004-283770 A JP 2007-326094 A International Publication No. 2013/42328

  However, the catalyst body described above has insufficient catalytic activity, and further improvement in catalytic activity is required. Further, the removal method combining the plasma generator and the metal fine particle catalyst of the present inventors is insufficient in decomposition of carbon monoxide and the like, and further improvement of the purification device is demanded.

  An object of this invention is to provide the novel technique which can improve a catalyst activity in a catalyst filter.

The gist of the present invention is as follows.
[1] a gold catalyst comprising a support made of an acidic solid metal oxide, and gold particles supported on the support;
A filter base material on which the gold catalyst is supported, and
The catalyst filter which is characterized in that to the surface of the filter substrate, the supported amount of the gold particles is less 0.005 g / ^{m 2} or more 0.5 g / ^{m 2.}
[2] The catalyst filter according to [1], wherein the solid metal oxide constituting the carrier is niobium oxide.
[3] The catalyst filter according to [1] or [2], wherein the support has a specific surface area of 20 m ² / g or more.
[4] The catalyst filter according to any one of [1] to [3], wherein the density of the gold particles supported on the carrier is 3 μmol / m ² or less.
[5] The catalyst filter according to any one of [1] to [4], wherein the carrier has mesopores having a volume of 0.1 cm ³ / g or more.
[6] The catalyst filter according to any one of [1] to [5], wherein the amount of gold particles supported on the carrier is 0.5% by mass or more and 12.0% by mass or less.
[7] The catalyst filter according to any one of [1] to [6], wherein the filter base material has a honeycomb shape or a fiber shape.

  ADVANTAGE OF THE INVENTION According to this invention, the novel technique which can improve catalyst activity in a catalyst filter can be provided.

  Hereinafter, embodiments of the present invention will be described in detail.

The catalyst filter of this embodiment includes a filter base material having air permeability and a gold catalyst supported on the surface thereof. The gold catalyst includes a support made of an acidic solid metal oxide and gold particles supported on the support.
In the catalyst filter of the present embodiment, the gold particles may be composite particles obtained by combining a metal element other than gold with gold particles or particles of an alloy of metal elements other than gold and gold. Metal elements other than gold are not particularly limited as long as they can form composite particles and alloys with gold, but noble metals such as Ag, Pt, Ru, Rh, Pd, Os, Ir, Sc, Ti, V, Cr, Mn, Fe , Co, Ni, Cu, Zn, Y, Zr, Nb, Mo, Tc, Cd, W, and other base metals.
In the case of composite particles in which a metal element other than gold is combined with gold particles, the size of the composite particles can be within a size range described later (particle diameter of 2 nm to 9 nm). Examples of metal particles (nanoparticles) other than gold particles that can be used in the composite particles include noble metals such as Pt, Pd, and Ir and their oxides, or base metals and their oxides. Two or more kinds of these noble metals and oxides thereof, base metals and oxides thereof may be mixed and supported on the carrier.

  In the catalyst filter of this embodiment, the gas to be treated comes into contact with the gold catalyst fixed to the filter base, and the component to be treated in the gas to be treated is oxidized and decomposed.

The gold catalyst, which is a component of the catalyst filter of the present embodiment, includes a support made of an acidic solid metal oxide and gold (Au) particles. The support is an acidic solid metal oxide.
In this specification, that the solid metal oxide is “acidic” means that the pH of the isoelectric point is 5 or less. Examples of the acidic solid metal oxide include niobium oxide, polyoxometalate (specifically, silicotungstic acid, silicomolybdic acid, phosphotungstic acid, phosphomolybdic acid, ammonium molybdate, ammonium tungstate, etc.), Examples include tungsten oxide, tantalum oxide, molybdenum oxide, and vanadium oxide. Among these, one or more selected from the group consisting of niobium oxide, polyoxometalate, tungsten oxide, tantalum oxide, molybdenum oxide, and vanadium oxide is preferable, and niobium oxide is more preferable because catalyst activity can be further increased.

The shape of the support is not particularly limited, but it is preferable to have a complicated three-dimensional structure because the catalytic activity can be further increased. In particular, niobium oxide, polyoxometalate, tungsten oxide, tantalum oxide, molybdenum oxide In vanadium oxide, in a basic unit consisting of MO ₄ tetrahedron, MO ₅ square weight, MO ₆ hexahedron, or MO ₅ trigonal bipyramid, oxygen atoms cross-link between the basic units by dehydration condensation reaction, apexes, ridges or faces It is preferably a three-dimensional structure formed by bonding via Of these, niobium oxide obtained by hydrothermal reaction is particularly preferable because of its high catalytic activity.
Further, it is possible to enhance the catalytic activity is preferably specific surface area of the support is 20 to 500 m ² / g, a specific surface area of more preferably from 100 to 300 m ² / g, specific surface area 150 Most preferably, it is 300 m ² / g. In addition, the specific surface area which concerns on this embodiment is the value computed using the automatic specific surface area measuring apparatus by BET method.

Since the catalytic activity can be further increased, the solid oxide as a support has mesopores (pores having a pore diameter of 2 nm or more and 50 nm or less), and the mesopore volume as the mesopore volume is 0.1 cm ³ / g or more. It is preferable that it is 0.2 cm ³ / g or more. In addition, although the upper limit of a mesopore volume is not specifically limited, From a viewpoint of adhesiveness with a filter base material, it is preferable to set it as 2.0 cm < ³ > / g or less, for example.
Here, the mesopores can be specified by obtaining a pore diameter value by the BET method. The mesopore volume is determined by the BJH method (EP Barrett, LG Joyner, PHHalenda: J. Am. Chem. Soc., 73, 373 (1951)).

Further, since the catalytic activity can be further increased, the average particle size of the support is preferably 5 to 1000 nm, and more preferably 5 to 500 nm.
In addition, the particle size of the particle | grains concerning this embodiment can calculate the particle size in the image photograph of a transmission electron microscope (TEM), and can obtain a particle size as the average value.

  Since the catalytic activity can be further increased, the gold particles in the gold catalyst according to this embodiment preferably have an average particle size of 5 nm or less, and more preferably 0.1 to 2 nm.

  Since the catalytic activity can be further increased, the content of the gold particles according to this embodiment is preferably 0.1 to 15.0% by mass, and 0.5 to 12.0% by mass with respect to the support. Is more preferable.

Moreover, since the manufacturing cost of the catalyst filter can be lowered, the density of the gold particles is preferably 3 μmol / m ² or less, more preferably 0.1 to 0.15 μmol / m ² . This density of ³ μmol / m ² or less is particularly effective when the specific surface area of the support is in the above-mentioned preferred range, and is particularly effective in that the activity increases even with a small gold density.
In addition, the said density can be calculated | required based on the following formula | equation (1).

Gold particle density = Gold particle content (% by weight) / 100/197 (molecular weight of gold, g / mol) / specific surface area of carrier (m ² / g) (1)

  In the gold catalyst according to this embodiment, the gold particles may be supported on the surface of the carrier. Further, when the carrier is a three-dimensional structure as described above, a cavity may be formed inside the carrier, and in that case, the gold particles may be supported on the surface of the carrier in the cavity.

Loading of the gold particles, to the surface of the filter substrate, is preferably at 0.005 g / ^{m 2} or more 0.5 g / ^{m 2} or less. If it exceeds 0.5 g / cm ² , the gold particles are likely to aggregate, and the catalytic activity is likely to be reduced as compared with the case where the amount is within the above range. Moreover, if it is less than 0.005 g / cm < ² >, sufficient catalyst activity is hard to be obtained compared with the case where it exists in the said range.
Since the catalytic activity can be further enhanced, when the gold particles having a particle size of 2 nm or more and 9 nm or less are supported by 0.005 g / m ² or more, the support preferably has mesopores. Further, it is possible to enhance the same catalytic activity, the amount of supported more preferably gold particles, is for the surface of the filter substrate 0.010 g / ^{m 2} or more 0.5 g / ^{m 2} or less, more preferably The amount of gold particles supported is 0.1 g / m ² or more and 0.5 g / m ² or less with respect to the surface of the filter substrate.

  In addition, in the gold catalyst of this embodiment, in addition to the gold particles, other metal elements other than the promoter particles and gold may be included, and the gold catalyst is not particularly limited. Specific examples include those in which promoter particles and gold particles are mixed. When using gold particles alone or using a mixture of gold particles and promoter particles, the gold particles can be within the above-mentioned size range (particle diameter of 2 nm or more and 9 nm or less). Examples of metal particles (nanoparticles) other than gold particles that can be used in the promoter particles include noble metals such as Pt, Pd, and Ir and their oxides, or base metals and their oxides. Two or more kinds of these noble metals and oxides thereof, base metals and oxides thereof may be mixed and supported on the carrier.

  In order to make the gold catalyst difficult to be affected by moisture, the gold catalyst may be hydrophobized, or a hygroscopic material or a desiccant may be added.

  The gold catalyst of this embodiment is formed on a filter substrate. At this time, the filter base material is not particularly limited as long as it has air permeability, but a honeycomb or fiber base material is preferable. A fibrous or honeycomb shape is preferable because pressure loss is reduced.

  The catalytic filter of the present embodiment can decompose a substance to be treated in the gas to be treated into an innocuous substance such as carbon dioxide and water by an oxidation reaction, and discharge it to the atmosphere. Substances that can be processed in the catalyst filter of the present embodiment include substances that volatilize from materials such as automobile interior materials, housing building materials / interior materials, and housings / members of home appliances, such as paints, adhesives, cleaning agents Substances that volatilize from the organic solvent. Specifically, hydrocarbons such as ethylene, benzene, xylene, toluene, ethylbenzene and styrene, alcohols such as methanol, ethanol and propyl alcohol, aldehydes such as formaldehyde and acetaldehyde, and ketones such as acetone and ethyl methyl ketone And amines such as ammonia, trimethylamine and triethylamine, thiols such as methanethiol, ethanethiol and propanethiol, and sulfur organic compounds such as methyl sulfide, methyl disulfide and dimethyl sulfoxide. In addition, carbon monoxide produced by incomplete combustion of tobacco, such as factory and kitchen combustion processes, household heaters, and the like can be treated.

  Since the filter base material may be heated to a high temperature when the catalyst filter of the present embodiment is manufactured, it is desirable that the filter base material be made of a heat-resistant material that can withstand the heating temperature. Specifically, the material of the filter substrate is preferably a metal material, ceramics, glass, carbon fiber, silicon carbide fiber, heat-resistant organic polymer material, or the like, and more preferably metal, metal oxide, or glass.

  Metal materials used for the filter substrate include refractory metals such as tungsten, molybdenum, tantalum, niobium, TZM (Titanium Zirconium Molybdenum), W-Re (tungsten-rhenium), noble metals such as silver and ruthenium, and their Alloys or oxides, special metals such as titanium, nickel, zirconium, chromium, inconel, hastelloy, general metals such as aluminum, copper, stainless steel, zinc, magnesium, iron and alloys containing these general metals or oxidation of these general metals Can be used. In addition, a member on which the above-described metal, alloy, or oxide film is formed by various plating and vacuum deposition, a CVD method, a sputtering method, or the like may be used as a metal material.

  Furthermore, examples of ceramics used for the filter substrate include ceramics such as earthenware, ceramics, stoneware, and porcelain, and ceramics such as cement, gypsum, enamel, and fine ceramics. The ceramic composition can include elemental, oxide, hydroxide, carbide, carbonate, nitride, halide, and phosphate compounds, and composites thereof. But you can.

  Further, as ceramics used for the filter substrate, further, barium titanate, lead zirconate titanate, ferrite, alumina, forsterite, zirconia, zircon, mullite, steatite, cordierite, aluminum nitride, silicon nitride, Examples thereof include silicon carbide and new carbon, and ceramics such as high-strength ceramics, functional ceramics, superconducting ceramics, nonlinear optical ceramics, antibacterial ceramics, biodegradable ceramics, and bioceramics.

  Glass used for the filter substrate includes soda lime glass, potash glass, crystal glass, quartz glass, chalcogen glass, uranium glass, water glass, polarizing glass, tempered glass, laminated glass, heat resistant glass / borosilicate glass, bulletproof Glasses such as glass, glass fiber, dichroic, gold stone (brown stone / sand gold stone / purple gold stone), glass ceramics, low melting point glass, metal glass, new glass, and saphiret can be exemplified.

  In addition, filter base materials include ordinary Portland cement, early-strength Portland cement, ultra-high-strength Portland cement, medium heat Portland cement, low heat Portland cement, sulfate-resistant Portland cement, and Portland cement blast furnace slag, fly ash, It is also possible to use cements such as blast furnace cement, silica cement, and fly ash cement, which are mixed cements to which a siliceous mixed material is added.

  In addition, titania, zirconia, alumina, ceria (cerium oxide), zeolite, apatite, silica, activated carbon, diatomaceous earth, and the like can be used for the filter base material. Furthermore, a metal oxide made of chromium, manganese, cobalt, nickel, tin, or the like can be used for the substrate.

  In addition, the filter base material is made of polyimide, polyetheretherketone, polyphenylene sulfide, polyaramid, polybenzothiazole, polybenzoxazole, polybenzimidazole, polyquinoline, polyquinoxaline, fluororesin, or phenol resin or epoxy resin. It is also possible to use a heat-resistant organic polymer material known to those skilled in the art, such as a curable resin.

The catalyst filter of this embodiment can be manufactured by, for example, performing a step of fixing a solid metal oxide to a filter base material and then supporting gold particles on the metal oxide.
The step of fixing the solid metal oxide to the filter base material includes, for example, immersing the filter base material in a suspension of the solid metal oxide to adhere the solid metal oxide as a carrier to the surface of the base material, and then 200 ° C. Can be fixed to the surface of the filter substrate by firing at 500 ° C.
Next, a supporting step of supporting gold particles on a solid metal oxide as a carrier using a gold colloid solution is performed (hereinafter, this manufacturing method is referred to as a colloid method). In addition, since it is a method especially preferable as a method of carrying | supporting a gold particle, although a colloid method is demonstrated below, it is not limited to this. For example, the gold catalyst is obtained by a method such as precipitation reduction method (DP method), precipitation precipitation method (DR method), DP urea method, solid phase mixing method (SG method), joint precipitation method (One-pot method), etc. Can also be carried.

In the gold particle supporting step, the solid metal oxide has a high specific surface area of preferably 20 m ² / g or more, more preferably 100 m ² / g or more, more preferably 150 m ² / g or more. As the gold colloid solution, a gold colloid solution containing gold particles having a particle diameter of 5 nm or less, preferably 0.5 to 3 nm can be used. When the specific surface area is out of the above range and when the particle size of the gold particles exceeds 5 nm, the gold particles are not supported on the support made of the solid metal oxide.
In the supporting step, gold particles can be supported by immersing a filter base material on which a solid metal oxide is fixed in a colloidal gold solution, and then lifting and firing the filter base material.
Specifically, for example, a filter base material in which a solid metal oxide is fixed in a colloidal gold solution is immersed, and the pH of the colloidal gold solution is adjusted to 8 to 11 using sodium hydroxide or the like for 30 minutes to 2 hours. Stir and mix. The gold content is preferably 0.01 to 20 parts by weight, more preferably 0.1 to 5 parts by weight with respect to 100 parts by weight of the solid metal oxide.
Next, 50 to 200 parts by weight of sodium borohydride is added to 100 parts by weight of gold particles in the colloidal solution. The filter base material is pulled up from the colloidal solution, washed, dried at 60 to 100 ° C., and then fired in air at 200 to 500 ° C. for 2 to 10 hours, whereby gold particles are formed on the surface of the solid metal oxide. A supported gold catalyst can be obtained.

As the solid metal oxide, a commercially available product may be used, and for example, a product obtained by a known production method may be used. For example, when a solid metal oxide is composed of niobium oxide, NH ₄ {NbO (C ₂ O ₄ ) ₂ (H ₂ O)} · nH ₂ O (Nb: 6 mmol) is dissolved in water, and 150 to Hydrothermal synthesis is performed at 300 ° C. for 10 to 30 hours. Next, the obtained solid is subjected to suction filtration, dried at 50 to 100 ° C., and subjected to heat treatment at 350 to 500 ° C. for 1 to 4 hours to obtain a solid metal oxide composed of niobium oxide.

A colloidal gold solution can be formed by dissolving a compound that forms a colloid in water. Examples of the compound that can be used at this time include tetrachloroauric acid, HAuCl ₄ , Au (en) ₂ Cl _{3 and the} like (en: ethylenediamine group). When tetrachloroauric acid is used, a colloidal gold solution can be obtained by introducing a toluene solution of tetrachloroauric acid and a toluene solution of tetraoctylammonium bromide into water in the presence of sodium borohydride. When HAuCl ₄ is used, a colloidal gold solution can be obtained by adding a toluene solution of tetraoctyl ammonium bromide together with HAuCl ₄ into water in the presence of sodium borohydride. As for Au (en) ₂ Cl ₃ , a colloidal gold solution can be obtained by putting it in water as it is. It is to be noted that sodium borohydride can be added at the time of supporting as described above, and the colloidal gold solution can be prepared without particular addition in colloidation.

The use environment of the filter of this embodiment is not particularly limited, and can be used at a suitable temperature and humidity according to the type of gas to be treated and the environment in which the filter is installed.
The filter of this embodiment can be used for the member and gas purification apparatus which have the effect | action or function which removes the harmful component in to-be-processed gas, for example.
Such members and devices include filters such as air conditioners and refrigerators, air purification filters installed in warehouses and showcases, air purifiers installed in offices and smoking rooms, exhaust gas purification devices such as internal combustion engines, and fuel Examples include a battery steam reformer. The member or the apparatus may be provided with a function that can set a use environment in which the catalyst body operates suitably, such as a heating mechanism of the catalyst body.

    Next, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only these examples.

[Example 1]
Ammonium niobium oxalate was dissolved in pure water and heated in a pressure vessel at 175 ° C. for 24 hours. The produced solid content was collected separately and washed several times with pure water.
The solid content and pure water were added to a beaker and stirred to prepare a suspension. A ceramic honeycomb (manufactured by Iwatani Corporation) was immersed in this suspension. Thereafter, the ceramic honeycomb was pulled up, the excess suspension was removed by air blow, and dried at 120 ° C. for 5 minutes. It was immersed again in the suspension, and the above immersion and drying operations were repeated three times.
Thereafter, drying and firing were performed at 120 ° C. for 6 hours and then at 400 ° C. for 2 hours to obtain a honeycomb substrate (niobium oxide / honeycomb) on which niobium oxide was fixed.

While a chloroauric acid aqueous solution, toluene, and tetraoctylammonium bromide were mixed and stirred, dodecanethiol was added and reduced with sodium borohydride. The toluene phase was recovered to obtain a gold colloid solution. Further, it was diluted with toluene to prepare a gold colloid solution having a predetermined concentration.
The above-mentioned niobium oxide / honeycomb was immersed for 90 minutes in a colloidal gold solution with a gold concentration adjusted to 1.67% by mass with respect to niobium oxide while stirring. The honeycomb was pulled up from the mixed solution and vacuum dried at 100 ° C. for 90 minutes. Subsequently, it put into the baking furnace, heated up to 300 degreeC over 1 hour, and baked as it was at 300 degreeC for 2 hours, and the catalyst filter was obtained.
About the obtained catalyst filter, the amount of gold particles supported on the substrate surface, the amount of gold particles supported on niobium oxide, the specific surface area of niobium oxide on the filter substrate surface, the mesopore diameter, the mesopore volume, and supported on niobium oxide. gold particle density are each 0.100 g ^/ m 2, 11.1 ^wt%, was 210m ² /g,3.7nm,0.65cm ³ /g,2.7μmol/m 2.
The amount of gold particles supported was measured using an atomic absorption photometer. The specific surface area of niobium oxide was calculated based on the BET method by measuring a nitrogen adsorption isotherm at a liquid nitrogen temperature using a high-accuracy gas adsorption amount measuring device (manufactured by Microtrack Bell). The mesopore diameter was similarly calculated based on the BET method. The mesopore volume was calculated based on the BJH method by measuring the desorption isotherm using the same apparatus. Further, the density of the gold particles supported on the carrier was calculated using the above formula (1) using the result of the amount of the precious metal particles supported and the result of the specific surface area of the carrier. In the following examples and comparative examples, the measurement was performed in the same manner.

[Example 2]
A catalyst filter was obtained in the same manner as in Example 1 except that the gold colloid solution was replaced with a gold colloid solution in which the gold concentration was adjusted to 1.50% by mass with respect to niobium oxide.
With respect to the obtained catalyst filter, the amount of gold particles supported on the substrate surface, the amount of gold particles supported on niobium oxide, and the density of gold particles supported on niobium oxide were 0.059 g / m ² and 10.0 mass, respectively. %, 2.4 μmol / m ² .

[Example 3]
A catalyst filter was obtained in the same manner as in Example 1 except that the gold colloid solution was replaced with a gold colloid solution in which the gold concentration was adjusted to 0.75 mass% with respect to niobium oxide.
With respect to the obtained catalyst filter, the amount of gold particles supported on the substrate surface, the amount of gold particles supported on niobium oxide, and the density of gold particles supported on niobium oxide were 0.024 g / m ² and 5.0 mass, respectively. %, 1.2 μmol / m ² .

[Example 4]
A catalyst filter was obtained in the same manner as in Example 1 except that the gold colloid solution was replaced with a gold colloid solution in which the gold concentration was adjusted to 0.45% by mass with respect to niobium oxide.
With respect to the obtained catalyst filter, the amount of gold particles supported on the substrate surface, the amount of gold particles supported on niobium oxide, and the density of gold particles supported on niobium oxide were 0.015 g / m ² and 3.0 mass, respectively. %, 0.7 μmol / m ² .

[Example 5]
A catalyst filter was obtained in the same manner as in Example 1 except that the gold colloid solution was replaced with a gold colloid solution in which the gold concentration was adjusted to 0.15% by mass with respect to niobium oxide.
With respect to the obtained catalyst filter, the amount of gold particles supported on the substrate surface, the amount of gold particles supported on niobium oxide, and the density of gold particles supported on niobium oxide were 0.006 g / m ² and 1.0 mass, respectively. %, 0.2 μmol / m ² .

[Comparative Example 1]
A catalyst filter was obtained in the same manner as in Example 1 except that the hydrothermally synthesized niobium oxide was replaced with a commercially available niobium oxide (manufactured by Sojitz Corporation).
About the obtained catalyst filter, the amount of gold particles supported on the substrate surface, the amount of gold particles supported on niobium oxide, the specific surface area of niobium oxide on the filter substrate surface, the mesopore diameter, the mesopore volume, and the niobium oxide gold particle density is respectively 0.004 g ^/ m 2, 1.1 ^wt%, it was 5.8m ² /g,4.2nm,0.11cm ³ /g,9.6μmol/m 2.

[Comparative Example 2]
A catalyst filter was obtained in the same manner as in Comparative Example 1 except that niobium oxide synthesized hydrothermally was replaced with titanium oxide (manufactured by Nippon Aerosil Co., Ltd.).
About the obtained catalyst filter, the amount of gold particles supported on the substrate surface, the amount of gold particles supported on titanium oxide, the specific surface area of titanium oxide on the filter substrate surface, the mesopore diameter, the mesopore volume, and the titanium oxide gold particle density is respectively 0.001 g ^/ m 2, 4.2 ^wt%, was 51m ² /g,5.8nm,0.14cm ³ /g,4.2μmol/m 2.

[Carbon monoxide removal test]
Carbon monoxide decomposition reaction was performed using the catalyst filters of Examples and Comparative Examples.
Carbon monoxide and air were mixed to prepare a test gas having a carbon monoxide concentration of 1,000 ppm, and the flow rate was controlled by a mass flow controller and supplied to the catalyst filter. For the analysis of the gas to be processed before treatment and the gas to be treated after 20 minutes, an infrared spectrophotometer (FTIR-6000, manufactured by JASCO Corporation) equipped with a gas cell having a long optical path (2.5 m) was used. The reaction conditions were a carbon monoxide concentration of 1,000 ppm, an oxygen concentration of 20%, a relative humidity of 60%, a gas flow rate of 1.0 L / min, and a reaction temperature of room temperature.
The CO removal rate was calculated using the following formula, and the results are shown in Table 1.
CO removal rate (%) = {(initial CO concentration−post-reaction CO concentration) / initial CO concentration} × 100

From the test results, it can be understood that the CO removal rate is more excellent in the catalyst filter of the example.

Claims (7)

A gold catalyst comprising a support made of an acidic solid metal oxide, and gold particles supported on the support;
A filter base material on which the gold catalyst is supported, and
The catalyst filter which is characterized in that to the surface of the filter substrate, the supported amount of the gold particles is less 0.005 g / ^{m 2} or more 0.5 g / ^{m 2.}   The catalyst filter according to claim 1, wherein the solid metal oxide constituting the support is niobium oxide. The catalyst filter according to claim 1 or 2, wherein the support has a specific surface area of 20 m ² / g or more. 4. The catalyst filter according to claim 1, wherein the density of the gold particles supported on the carrier is 3 μmol / m ² or less. 5. 5. The catalytic filter according to claim 1, wherein the carrier has mesopores having a volume of 0.1 cm ³ / g or more.   The catalyst filter according to any one of claims 1 to 5, wherein the amount of gold particles supported on the carrier is 0.5% by mass or more and 12.0% by mass or less. The catalytic filter according to any one of claims 1 to 6, wherein the filter base has a honeycomb-like or fibrous shape.