TWI382959B - Production method for titanium oxide particles - Google Patents

Description

Method for producing titanium oxide particles

The present invention relates to a method for producing a titanium oxide particle having a box shape of a decahedron.

Recently, it has been reported that a titanium oxide particle having a box shape of a decahedron and mainly composed of an anatase type crystal (hereinafter referred to as "10-facet titanium oxide particle") and a method for producing the same (Patent Documents 1 and 2 and Non-Patent Document 1 refer to). In addition, in these reports, it is also reported that the 10 facet titanium oxide particles are highly active with a photocatalyst.

The method for producing the 10-faceted titanium oxide particles reported in the above-mentioned documents is almost always a method in which a gas containing titanium tetrachloride and oxygen is rapidly heated and rapidly cooled under certain conditions. However, the 10-facet titanium oxide particles obtained by such a method have a particle diameter of almost 100 nm or more. Therefore, in the conventional manufacturing method, it is difficult to selectively obtain a 10-faceted titanium oxide particle having a particle diameter of 100 nm or less, and the problem is that it exists in a box shape having a 10-faceted body, and Also reduce the particle diameter.

On the other hand, in the method of obtaining titanium oxide titanium oxide, a method of using oxygen gas and water vapor as an oxidizing gas when titanium tetrachloride is oxidized is known (refer to Patent Document 3).

Patent Document 1: International Publication No. 04/063431, Patent Document 2: JP-A-2006-52099 Patent Document 3: Patent No. 3365355

Non-Patent Document 1: Kusano. Temple field. Abe. Otani, the 98th catalyst workshop (September 1999) seminar A pre-collection, page 234

Invention disclosure

In view of such a conventional problem, it is an object of the present invention to provide a method for producing a titanium oxide particle having a small particle size of a titania titanium oxide particle selectively and efficiently.

The inventors of the present invention have repeatedly tried to solve the above problems, and as a result, it has been found that when titanium tetrachloride is oxidized at a high temperature in a gas phase, it is used under the specific conditions: rapid heating and rapid cooling, and use. When water vapor is used as the method of the oxidizing gas, the 10-faceted titanium oxide particles having a particle diameter of 100 nm or less can be selectively obtained.

That is, the present invention provides the following means.

[1] A method for producing titanium oxide particles, which is characterized in that a gas having a titanium tetrachloride vapor and an oxidizing gas containing water vapor are brought into contact to selectively produce a box shape having a pentahedron, And a method for producing titanium oxide particles of a 10-faceted titanium oxide particle having a particle diameter in the range of 1 nm to 100 nm; characterized by comprising: a gas containing titanium tetrachloride vapor which has been preheated at 500 ° C or higher, And an oxidizing gas containing water vapor Mix and feed the step of heating to an environment above 800 °C.

[2] The method for producing titanium oxide particles according to the above [1], wherein the gas system containing titanium tetrachloride vapor contains a mixed gas of titanium tetrachloride vapor and oxygen.

[3] The method for producing titanium oxide particles according to the above [1] or [2], wherein the oxidizing gas system containing water vapor contains a mixed gas of water vapor and oxygen.

[4] The method for producing titanium oxide particles according to any one of [1] to [3] wherein the residence time of the gas in the environment heated to 800 ° C or higher is 300 msec or less.

[5] The method for producing titanium oxide particles according to the above [4], wherein the residence time is 100 milliseconds or less.

[6] The method for producing titanium oxide particles according to any one of [1] to [5] wherein the concentration of titanium tetrachloride in the gas containing titanium tetrachloride vapor is 3 to 40% by volume.

[7] The method for producing a titanium oxide particle according to any one of the above [1] to [6] wherein, in the gas containing titanium tetrachloride vapor (the mass of oxygen (in terms of O ₂ ) [mol]) The ratio of / (the mass of titanium tetrachloride [mol]) is 0.1 to 7.

[8] The method for producing titanium oxide particles according to any one of [1] to [7] wherein the concentration of the water vapor in the water vapor-containing oxidizing gas is 10 to 80% by volume.

[9] The method for producing a titanium oxide particle according to any one of the above [1] to [8], wherein (the mass of the oxygen (in terms of O ₂ ) [mol]) / in the oxidizing gas containing water vapor The ratio of the mass of water vapor [mol] is 0.1 to 5.

[10] The method for producing a titanium oxide particle according to any one of [1] to [9] wherein the amount of the oxidizing gas containing water vapor is relative to the amount of the gas containing titanium tetrachloride vapor The volume ratio is 0.5 to 5 times.

[11] The method for producing a titanium oxide particle according to any one of the above [1] to [10] wherein the composition of the gas combined with the gas containing titanium tetrachloride vapor and the gas containing water vapor is tetrachloro Titanium: Oxygen: Water vapor = 1: 0.5 ~ 13: 0.3 ~ 5 (volume ratio).

[12] The method for producing a titanium oxide particle according to the above [11], wherein the composition of the gas combined with the gas containing titanium tetrachloride vapor and the gas containing water vapor is titanium tetrachloride: oxygen: water vapor = 1:1~6: 0.3~3 (volume ratio).

As described above, in the method for producing titanium oxide particles of the present invention, when titanium tetrachloride is oxidized in a gas phase at a high temperature, a method of rapidly heating and rapid cooling and a use of water vapor under certain conditions are employed. As a method of oxidizing gas, a method of combining them can be used to selectively and efficiently produce a 10-pectite titanium oxide particle having a particle diameter in the range of 1 nm to 100 nm. Further, the obtained titanium oxide particles having a small particle diameter are suitable as a photocatalyst material. Therefore, according to the present invention, an appropriate tenahedral titanium oxide particle can be industrially produced as a photocatalytic material.

The best form of implementing the invention

Hereinafter, the method for producing the titanium oxide particles of the present invention will be described in detail with reference to the drawings.

The method for producing titanium oxide particles of the present invention is characterized in that a gas having a titanium tetrachloride vapor and an oxidizing gas containing water vapor are brought into contact with each other to selectively produce a box shape having a decahedron and a method for producing titanium oxide particles of a 10-faceted titanium oxide particle having a particle diameter in the range of 1 nm to 100 nm; characterized by comprising: a gas containing titanium tetrachloride vapor which has been preheated at 500 ° C or higher, and The oxidizing gas containing water vapor is mixed and fed to an environment heated to 800 ° C or higher.

Specifically, the "10-sided titanium oxide particles" in the present invention means a titanium oxide particle having a box shape of a decahedron, similarly to the titanium oxide particles defined in Patent Document 1.

In addition, "selectively producing the icosahedral titanium oxide particles" means that the obtained titanium oxide powder is arbitrarily sampled, and when observed by an electron microscope, the titanium oxide particles observed in an arbitrary field of view are at least 80. When it is more than %, it should be the above condition.

The "oxidizing gas containing water vapor" in the present invention refers to a gas which contains water vapor and which can form titanium oxide when it is brought into contact with titanium tetrachloride vapor at a high temperature. In the present invention, the oxidizing gas containing water vapor is preferably a two-component gas containing at least oxygen and water vapor. Specific examples of the oxidizing gas containing water vapor include a gas containing oxygen (O ₂ ) and water vapor, a gas containing ozone (O ₃ ) and water vapor, and the like. Further, the oxidizing gas containing water vapor may be a mixture of these gases, or the gas may be diluted by an inert gas. Therefore, the oxidizing gas containing water vapor can be a mixed gas of steam and oxygen, a mixed gas of steam and an inert gas, a mixture of water vapor and oxygen and an inert gas, and further, oxygen and an inert gas. Air can also be used as a mixed gas.

On the other hand, in the present invention, a gas containing titanium tetrachloride vapor can be, for example, a mixed gas of titanium tetrachloride vapor and an inert gas, a mixed gas of titanium tetrachloride vapor and oxygen, and a titanium tetrachloride vapor. And a mixed gas of oxygen and an inert gas. In addition, air may be used as a mixed gas of oxygen and an inert gas.

In the present invention, a gas containing titanium tetrachloride vapor is important in that the titanium oxide is not formed in the preheating step.

However, when the gas containing titanium tetrachloride vapor is a mixed gas of only titanium tetrachloride vapor and an inert gas, the mixed gas is sent to an environment heated to 800 ° C or higher, titanium tetrachloride vapor. The mixing of oxygen and oxygen will not be sufficient, and it will be difficult to selectively obtain a 10-faceted shape.

Therefore, in the present invention, the gas containing titanium tetrachloride vapor is either a mixed gas of titanium tetrachloride vapor and oxygen, or a titanium tetrachloride vapor and a mixed gas of oxygen and an inert gas. Preferably.

In the present invention, when a gas containing titanium tetrachloride vapor is brought into contact with an oxidizing gas containing water vapor, a reaction occurs immediately. Therefore, in order to selectively obtain the octahedral titanium oxide particles, the temperature at the time of contact is important. Specifically, the titanium tetrachloride vapor contains an oxidizing gas of water vapor. The body must be preheated above 500 °C before contact. When the preheating is less than 500 ° C, when a gas containing titanium tetrachloride vapor is brought into contact with a gas containing water vapor, good 10 facet titanium oxide particles cannot be obtained.

In the present invention, after the gas containing titanium tetrachloride vapor is brought into contact with the oxidizing gas containing water vapor, it is necessary to feed the gas to an environment heated to 800 ° C or higher. It is preferably added to the environment heated to 800 ° C or more immediately after the contact. Further, the gas residence time in an environment heated to 800 ° C or higher is preferably 300 msec or less, and preferably 100 msec or less. When the residence time of the gas exceeds 300 msec, the particle diameter of the obtained titanium oxide particles becomes large, and the rutile crystals also increase, and it is difficult to obtain good ten-face titanium oxide particles.

In the present invention, the concentration of titanium tetrachloride in the gas containing titanium tetrachloride vapor is preferably from 3 to 40% by volume. When the concentration of titanium tetrachloride is less than 3% by volume, the ratio of the obtained 10-face titanium oxide particles becomes small. On the other hand, when the concentration of titanium tetrachloride is more than 40% by volume, the particle diameter of the titanium oxide particles becomes large. Therefore, the concentration of titanium tetrachloride in the gas containing titanium tetrachloride vapor is preferably in the range of 3 to 40% by volume, and more preferably in the range of 15 to 30% by volume.

In the present invention, the ratio of the mass of the oxygen (in terms of O ₂ ) [mol] / (the mass of the titanium tetrachloride [mol]) in the gas containing titanium tetrachloride vapor is 0.1 to 7 It is better.

If the value is less than 0.1, the ratio of the obtained 10-facet titanium oxide particles is reduced. On the other hand, when the value exceeds 7, the particle diameter of the titanium oxide particles becomes large. Therefore, the ratio of the mass of oxygen (O ₂ in terms of mass ratio [mol]) / (the mass of titanium tetrachloride) [mol] in the gas containing titanium tetrachloride vapor is in the range of 0.1 to 7. Preferably, the range of 2 to 5 is optimal.

In the present invention, the concentration of water vapor in the oxidizing gas containing water vapor is preferably from 10 to 80% by volume. When the concentration of water vapor is less than 10% by volume, the particle diameter of the titanium oxide particles becomes large. On the other hand, when the concentration of water vapor exceeds 80% by volume, the ratio of the obtained 10-facet titanium oxide particles is reduced. Therefore, the concentration of water vapor in the oxidizing gas containing water vapor is preferably in the range of 10 to 80% by volume, and more preferably in the range of 15 to 40% by volume.

In the present invention, the ratio of the mass of oxygen (O ₂ in terms of mass ratio [mol]) / (the mass of water vapor [mol]) in the oxidizing gas containing water vapor is preferably 0.1 to 5 . If the value is less than 0.1, the ratio of the obtained 10-facet titanium oxide particles is reduced. On the other hand, when the value exceeds 5, the ratio of the obtained 10-facet titanium oxide particles is reduced. Therefore, the ratio of the mass of oxygen (O ₂ in terms of mass ratio [mol]) / (the mass of water vapor [mol]) in the oxidizing gas containing water vapor is preferably in the range of 0.1 to 5. And the range of 0.5~3 is the best.

In the present invention, the amount of the oxidizing gas containing water vapor is preferably 0.5 to 5 times by volume based on the amount of the gas containing titanium tetrachloride vapor. When the volume is less than 0.5 times, the particle diameter of the titanium oxide particles becomes large. On the other hand, when the volume exceeds 5 times, for example, the proportion of the 10 facet titanium oxide particles is reduced. Therefore, an oxidizing gas containing water vapor The amount is preferably 0.5 to 5 times in terms of volume ratio with respect to the amount of the gas containing titanium tetrachloride vapor, and is preferably in the range of 0.8 to 2.

In the present invention, the volume ratio of titanium tetrachloride and oxygen and water vapor (titanium tetrachloride: oxygen: water vapor) in the gas combined with the gas containing titanium tetrachloride vapor and the gas containing water vapor The range of 1:0.5 to 13:0.3 to 5 (volume ratio) is preferable, and the range of titanium tetrachloride: oxygen: water vapor = 1:1 to 6: 0.5 to 3 (volume ratio) is optimal.

When it exceeds this range, it is difficult to selectively obtain the 10 facet titanium oxide particles. The reason for this is still unclear, but it is presumed that the concentration and speed of titanium tetrachloride due to water vapor decomposition, the reaction rate of unreacted titanium tetrachloride and oxygen after hydrolysis, and the retention in the reaction zone Time and other related parties.

As described above, the method for producing titanium oxide particles to be used in the present invention is a method in which titanium tetrachloride is oxidized in a gas phase at a high temperature, and the method is as follows: rapid heating and rapid cooling, and use of water vapor as a method. The method of oxidizing gas can selectively and efficiently produce 10-island titanium oxide particles having a particle diameter ranging from 1 nm to 100 nm. Further, the obtained titanium oxide particles having a small particle diameter are suitable as a photocatalyst material. Therefore, according to the present invention, an appropriate tenahedral titanium oxide particle can be industrially produced as a photocatalytic material.

Next, Fig. 1 shows an example of a reaction apparatus used in a method for producing titanium oxide particles suitable for the present invention.

The reaction apparatus, as shown in FIG. 1, is provided to contact a gas containing titanium tetrachloride vapor and an oxidizing gas containing water vapor. The reaction tube 1 and the infrared electric furnace 2 for partially heating the reaction tube 1 (heating unit 1a) 2, and the product recovery unit 3 for recovering the titanium oxide powder generated in the reaction tube 1 .

Specifically, for the reaction tube 1, for example, a cylindrical tube made of quartz or the like can be used. Further, in the reaction tube 1, the introduction tube 4 for introducing the oxidizing gas containing water vapor is connected to the one end side (upstream side), and the introduction tube for introducing the gas containing titanium tetrachloride vapor is introduced. 5 is inserted into the inside from the one end side (upstream side).

On the flow side of the introduction pipe 4, for example, an inlet port 4a for introducing water and oxygen (O ₂ ) and nitrogen gas, and a vaporizer 6 for vaporizing the water introduced into the inlet port 4a are provided. The water vapor-containing oxidizing gas (containing water vapor and oxygen (O ₂ ) and nitrogen gas) introduced from the inlet 4a is passed through the gasifier 6 to become steam, oxygen (O ₂ ), and nitrogen. The mixed gas is introduced into the reaction tube 1 by the introduction tube 4.

On the flow side of the introduction pipe 5, for example, an introduction port 5a into which titanium tetrachloride (TiCl ₄ ) is introduced, an introduction port 5b into which oxygen (O ₂ ) is introduced, and four introduced into the introduction port 5a are provided. A gasifier 7 for gasification of titanium chloride (TiCl ₄ ). Therefore, the gas containing titanium tetrachloride (TiCl ₄ ) vapor introduced from the introduction port 5a (containing titanium tetrachloride and oxygen (O ₂ )) is converted into titanium tetrachloride by passing through the gasifier 6. (TiCl ₄ ) A mixed gas of steam and oxygen (O ₂ ) is introduced into the reaction tube 1 through the introduction pipe 5.

Further, as described above, the introduction tube 5 is housed inside the reaction tube 1 from one end side (upstream side) of the reaction tube 1. Next, the infrared rays from the infrared electric furnace 2 are irradiated on the front end of the introduction tube 5. Then, by When the other end side (downstream side) of the reaction tube 1 starts, the buffer 8 is inserted. The buffer 8 guides the gas introduced into the reaction tube 1 to the outer peripheral side of the reaction tube 1 which is at a high temperature, and for example, the tip end of the quartz tube is formed into a sharp shape and is closed. Further, the tip end of the buffer 8 is opposed to the tip end of the introduction tube 5 in the reaction tube 1, and the tip end portion of the introduction tube 5 and the tip end portion of the buffer 8 are positioned on the heating portion 1a of the reaction tube 1. Further, the buffer 8 also has a function of shortening the residence time of the gas in the reaction zone B to be described later.

The reaction tube 1 of the heating unit 1a is wound with a platinum plate. The heating unit 1a can be rapidly heated and rapidly cooled by the combination of the platinum plate and the infrared electric furnace 2. That is, the infrared rays irradiated by the infrared electric furnace 2 are absorbed by the platinum plate and generate heat, and only the portion in contact with the platinum is partially heated. Thereby, the heating portion 1a can be heated to about 1200 °C. Further, the temperature of the heating unit 1a can be arbitrarily set by controlling the infrared ray of the infrared ray oven 2 to be controlled by a temperature controller (not shown).

Further, in the heating portion 1a in which the platinum plate is wound, before the leading end of the introduction tube 5, a gas containing titanium tetrachloride vapor and a portion containing an oxidizing gas containing water vapor are preheated (so-called "preheating zone" A"); and the downstream end of the introduction tube 5 flows downward, more specifically, from the tip end of the introduction tube 5 to the end portion of the heating portion 1a, the titanium tetrachloride is oxidized in the gas phase at a high temperature. Part (the so-called "reaction zone B").

The product recovery unit 3 is a bag filter that generates oxygen in the reaction tube 1 through a discharge pipe 9 connected to the other end side (downflow side) of the reaction tube 1. The titanium powder is recovered. Further, in the product recovery unit 3, it is preferable that the discharge tube 9 is not blocked, and it is preferable that the product can be sucked by a pump (not shown) downstream.

In the reaction apparatus having the above configuration, the oxidizing gas containing water vapor introduced into the reaction tube 1 from the introduction tube 4 and the gas containing titanium tetrachloride vapor introduced into the tube 5 are each in the preheating zone. After preheating to 500 ° C or higher, the mixture is further mixed in the reaction zone B and heated to 800 ° C or higher. The gas containing titanium tetrachloride vapor and the oxidizing gas containing water vapor are reacted immediately after the reaction in the reaction zone B, and the obtained reaction gas passes through the reaction zone B with a residence time of 300 msec or less. Then, the gas passing through the reaction zone B is immediately cooled and sent back to the product recovery unit 3.

When such a reaction apparatus is used, since titanium tetrachloride is oxidized at a high temperature in a gas phase, it can be used in combination: a method of rapid heating and rapid cooling, and a method of using water vapor as an oxidizing gas, under the above conditions. Then, a 10-pectite titanium oxide particle having a box shape of a decahedron and having a particle diameter of 1 nm to 100 nm can be selectively and efficiently produced.

Example

Hereinafter, the effects of the present invention will be further described in detail by way of examples. The present invention is not limited to the embodiments, and may be practiced without departing from the spirit and scope of the invention.

Example 1

In the first embodiment, the reaction device shown in FIG. 1 described above is used, and The production of the titanium oxide powder was actually carried out under the following conditions.

That is, the platinum plate is wound around the heating portion 1a of the reaction tube 1 by about 10 cm, and in the case where the infrared heating furnace 2 is irradiated with infrared rays in the portion (heating portion 1a), the infrared heating furnace 2 is temperature-controlled. The device controls the surface temperature of the platinum plate to 1200 °C.

The reaction tube 1 was a quartz tube having an inner diameter of 21.4 mm. The buffer 8 was a quartz tube having an outer diameter of 12.7 mm, and the tip was made into a sharp shape of about 30° and occluded. Further, the cross-sectional area of the heating portion 1a is 2.3 cm ² .

The tip end of the introduction tube 5 into which the gas containing titanium tetrachloride vapor is introduced is disposed in a heating portion 1a around which a platinum plate is wound (the width of the platinum plate is 10 cm, so the width of the heating portion 1a is also 10 cm) At the upper end of the flow, the 6 cm downstream is used as the preheating zone A. The reaction zone B (4 cm) is a high-heat reaction zone from the tip end of the introduction pipe 5 until the tip end of the heating portion 1a.

In the oxidizing gas containing water vapor, a mixed gas containing water vapor and oxygen (O ₂ ) and nitrogen is used. The mixed gas of water, oxygen, and nitrogen is introduced into the reaction tube 1 after being introduced into the vaporizer 6 through the introduction port 4a, and then passing the oxidizing gas containing water vapor from the tip end of the introduction pipe 5. Further, the composition of the mixed gas after passing through the gasifier 6 is water vapor: oxygen: nitrogen = 20:20:60 (volume ratio), and the mixed gas is introduced in the case where the total flow rate is 600 NmL/min. .

In the gas containing titanium tetrachloride vapor, a mixed gas of titanium tetrachloride vapor and oxygen (O ₂ ) is used. TiCl ₄ is introduced from the introduction port 5a, oxygen (O ₂ ) is introduced from the introduction port 5b, passed through the vaporizer 7, and then introduced into the reaction tube 1 from the tip end of the introduction tube 5. Further, the composition of the mixed gas after passing through the gasifier 7 is titanium tetrachloride: oxygen = 20:80 (volume ratio), and the mixed gas is introduced in the case where the total flow rate is 600 NmL/min.

Further, the composition of the total reaction gas is titanium tetrachloride: oxygen: water vapor = 1:5:1, and the residence time of the reaction gas in the reaction zone B is about 50 msec.

Comparative example 1

The oxidizing gas containing water vapor was changed to an oxidizing gas containing no water vapor, that is, a mixed gas of oxygen and nitrogen was introduced from the introduction port 4a, and the titanium oxide powder was subjected to the same conditions as in Example 1. Manufacturing.

Comparative example 2

Except that the oxidizing gas containing water vapor is not introduced, only the mixed gas of titanium tetrachloride vapor and oxygen (O ₂ ) (concentration of titanium tetrachloride is 6%) is slowly introduced into the tube 5 (300 NmL/min). The production of the titanium oxide powder was carried out under the same conditions as in Example 1 except for the introduction.

Next, the titanium oxide powders obtained in Example 1, Comparative Example 1, and Comparative Example 2 were observed under an electron microscope.

Hereinafter, the respective production conditions of the first embodiment, the comparative example 1, and the comparative example 2, and the observation results of the obtained titanium oxide particles are summarized as shown in Table 1. Shown in it. Further, the titanium oxide powder was obtained by using three samples of any of the samples, and each was introduced into a sample chamber of a scanning electron microscope, and observed at five places.

As shown in Table 1, the titanium oxide powder obtained in Example 1 had a 10-diameter titanium oxide particle having a particle diameter of 50 to 90 nm.

On the other hand, the titanium oxide powder obtained in Comparative Example 1 was not a octahedral titanium oxide particle, and the particle diameter also showed a wide distribution in the range of 30 to 200 nm.

Further, the titanium oxide powder obtained in Comparative Example 2 was a 10-facet titanium oxide particle, but the particle diameter showed a wide distribution in the range of 70 to 150 nm and contained a particle diameter.

As described above, according to the present invention, it is possible to selectively and efficiently produce a 10-pectite titanium oxide particle having a box shape of a decahedron and having a particle diameter of 1 nm to 100 nm.

Industrial availability

According to the production method of the present invention, the 10 facet titanium oxide particles having a particle diameter in the range of 1 nm to 100 nm can be selectively and efficiently produced. Further, the obtained small-diameter titanium oxide particles are suitable as a photocatalyst material. Therefore, according to the present invention, an appropriate tenahedral titanium oxide particle can be industrially produced as a photocatalytic material.

1‧‧‧Reaction tube

1a‧‧‧heating department

2‧‧‧Infrared appliance furnace

3‧‧‧Product Collection Department

4‧‧‧Introduction tube

5‧‧‧Introduction tube

6‧‧‧ gasifier

7‧‧‧ gasifier

8‧‧‧ Buffer

9‧‧‧Draining tube

Fig. 1 is a view showing a part of a reaction apparatus suitable for use in the production of titanium oxide particles of the present invention.

1‧‧‧Reaction tube

1a‧‧‧heating department

2‧‧‧Infrared appliance furnace

3‧‧‧Product Collection Department

4‧‧‧Introduction tube

4a‧‧‧Import

5‧‧‧Introduction tube

5a‧‧‧Import

5b‧‧‧Import

6‧‧‧ gasifier

7‧‧‧ gasifier

8‧‧‧ Buffer

9‧‧‧Draining tube

Claims (12)

A method for producing titanium oxide particles by selectively contacting a gas containing titanium tetrachloride vapor and an oxidizing gas containing water vapor to form a box shape having a decahedron and having a particle diameter Further, a method for producing titanium oxide particles of a 10-faceted titanium oxide particle in the range of 1 nm to 100 nm, which comprises: a gas containing titanium tetrachloride vapor which has been preheated at 500 ° C or higher, and water containing The oxidizing gas of the vapor is mixed and fed to an environment heated to 800 ° C or higher. The method for producing titanium oxide particles according to claim 1, wherein the gas system containing titanium tetrachloride vapor contains a mixed gas of titanium tetrachloride vapor and oxygen. The method for producing titanium oxide particles according to claim 1, wherein the steam-containing oxidizing gas system contains a mixed gas of water vapor and oxygen. The method for producing titanium oxide particles according to claim 1, wherein the residence time of the gas in the environment heated to 800 ° C or higher is 300 msec or less. A method for producing titanium oxide particles according to claim 4, wherein the residence time is 100 milliseconds or less. The method for producing titanium oxide particles according to the first aspect of the invention, wherein the concentration of titanium tetrachloride in the gas containing titanium tetrachloride vapor is 3 to 40% by volume. The method for producing titanium oxide particles according to the first aspect of the invention, wherein the mass of the oxygen (in terms of O ₂ ) [mol] / (the mass of titanium tetrachloride) in the gas containing titanium tetrachloride vapor The ratio of [mol]) is 0.1~7. The method for producing titanium oxide particles according to the first aspect of the invention, wherein the concentration of the water vapor in the oxidizing gas containing water vapor is 10 to 80% by volume. The method for producing a titanium oxide particle according to the first aspect of the invention, wherein the oxidizing gas containing water vapor (the mass of oxygen (in terms of O ₂ ) [mol]) / (the mass of water vapor [mol] The ratio is 0.1~5. The method for producing titanium oxide particles according to the first aspect of the invention, wherein the amount of the oxidizing gas containing water vapor is 0.5 to 5 times by volume relative to the amount of the gas containing titanium tetrachloride vapor. . The method for producing titanium oxide particles according to claim 1, wherein the composition of the gas containing the titanium tetrachloride vapor and the gas containing water vapor is titanium tetrachloride: oxygen: water vapor = 1 : 0.5~13: 0.3~5 (volume ratio). The method for producing titanium oxide particles according to claim 11, wherein the composition of the gas containing the titanium tetrachloride vapor and the gas containing water vapor is titanium tetrachloride: oxygen: water vapor = 1 :1~6: 0.3~3 (volume ratio).