Photocatalytic decomposition apparatus

Abstract

To provide a photocatalytic decomposition apparatus that achieves efficient supply and evaporation of water decomposed with a photocatalyst.SOLUTION: A photocatalytic decomposition apparatus 100 of the invention is a water decomposition apparatus using a photocatalyst, and includes: a vapor generation part 102 that includes a hole for sucking up water, and generates heat by absorbing light 105 supplied from a light source; and a photocatalytic decomposition part 103 where vapor generated by the vapor generation part 102 and the photocatalyst come into contact with each other, and the light supplied from the light source is irradiated to the photocatalyst.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to a photocatalytic decomposition device. [Background technology]

[0002] In recent years, artificial photosynthesis systems have been developed that use solar energy to produce CO 2 It is attracting attention as a clean energy generation method because it can synthesize compounds that can be used as energy carriers such as hydrogen without emitting CO2. One of the means to sustainably generate hydrogen and other gases is to use renewable energy such as sunlight and unused seawater.

[0003] An example of such a technique is Patent Document 1. Patent Document 1 discloses a water photolysis device having a casing 1 with a light-transmitting window 12 that transmits sunlight L, and a photolysis layer 5 provided on the casing 1. This photolysis device is placed in a floating state on a water layer 9, and water vapor is evaporated from the water layer 9 by irradiation with sunlight L, and this water vapor is introduced into the photolysis layer 5, and in the photolysis layer 5, photocatalyst particles 52 are excited by sunlight L, and the introduced water vapor is converted into water. Basic and oxygen do The configuration of Patent Document 1 is said to provide a water photolysis device that can efficiently obtain hydrogen and oxygen by suppressing the reverse reaction, and can also effectively utilize solar energy to promote the photolysis of water. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2004 / 085306 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional artificial photosynthesis systems, when seawater is directly decomposed, chloride ions in the seawater are discharged as hypochlorous acid or toxic chlorine gas, which could lead to corrosion and deterioration of the equipment and environmental pollution.

[0006] In addition, although chloride ions can be removed by steaming seawater once, a mechanism is required to efficiently supply seawater to the device and efficiently steam it. Under these circumstances, there has been a need to study a configuration for more efficiently supplying and steaming seawater than the conventional techniques such as those described in Patent Document 1 above.

[0007] In view of the above circumstances, an object of the present invention is to provide a photocatalytic decomposition device that can efficiently supply and vaporize water to be decomposed by photocatalysis. [Means for solving the problem]

[0008] One aspect of the present invention for solving the above problems is a water decomposition device that uses a photocatalyst, characterized in that it comprises a steam generation unit that has pores that suck up water and absorbs light supplied from a light source to generate heat, and a photocatalytic decomposition unit in which the steam generated in the steam generation unit comes into contact with the photocatalyst and in which the photocatalyst is irradiated with light supplied from the light source.

[0009] More specific configurations of the present invention are described in the claims. Effect of the Invention

[0010] According to the present invention, it is possible to provide a photocatalytic decomposition device that can efficiently supply and vaporize water to be decomposed by photocatalysis.

[0011] Problems, configurations and effects other than those described above will become apparent from the following description of the embodiments. [Brief description of the drawings]

[0012] [Figure 1A] FIG. 1 is a schematic diagram showing a photocatalytic decomposition device according to a first embodiment of the present invention; [Figure 1B]Enlarged view of the steam generating section of Figure 1A [Diagram 2] FIG. 1 is a schematic diagram showing a photocatalytic decomposition device according to a second embodiment of the present invention; [Diagram 3] FIG. 1 is a schematic diagram showing a photocatalytic decomposition device according to a third embodiment of the present invention; [Figure 4] FIG. 1 is a schematic diagram showing a photocatalytic decomposition device according to a fourth embodiment of the present invention; DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The configuration of the present invention will be described in detail below with reference to the drawings. EXAMPLES

[0014] FIG. 1A is a schematic diagram of a photocatalytic decomposition device of Example 1. As shown in FIG. 1A, the photocatalytic decomposition device 100 of the present invention includes a steam generating unit 102 that absorbs light 105 supplied from a light source, generates heat, and generates steam 106 from water obtained from a water layer 107, a photocatalytic decomposition unit 103 that has a photocatalyst and causes the light 105 supplied from the light source and the steam 106 generated in the steam generating unit 102 to react with the photocatalyst to decompose the steam 106, and a housing 101 that houses the steam generating unit 102 and the photocatalytic decomposition unit 103. In this example, the sun is used as the light source, and seawater is used as the water layer 107. Each configuration will be described in detail below.

[0015] (1) Housing The housing 101 is made of a material that transmits light 105 incident from a light source such as the sun. (2) Steam generation section

[0016] 1B is an enlarged view of the steam generating section 102 in FIG. 1A. As shown in FIG. 1B, the steam generating section 102 is made of a material having a large number of pores 120 (pores that penetrate the steam generating section 102 from the upper end to the lower end). Thin The tube phenomenon allows water to be efficiently sucked up in the direction of the black arrow in Figure 1B. 102The heat generated by the light 105 can efficiently vaporize the water that is sucked up from the water layer 107 and remains on the surface.

[0017] The material constituting the vapor generating unit 102 is preferably a carbon-based material such as graphite, graphene, or carbon nanotubes.

[0018] Steam generating unit 102 The porosity (volume ratio of pores in the steam generating section 102) is 10%. volume More than 90% volume If the porosity is less than 10%, it becomes difficult to provide holes that penetrate the steam generating unit 102 from the upper end to the lower end, and the photocatalyst Decomposition It is not possible to suck up enough water to efficiently supply water to the portion 103. On the other hand, if the porosity exceeds 90%, the strength becomes insufficient and the portion will break, making it difficult to continuously split water.

[0019] (3) Photocatalytic decomposition section 103 The photocatalytic decomposition unit 103 has a photocatalytic material, and converts the steam generated in the steam generation unit 102 and the water liquefied by cooling the steam into hydrogen (H 2 ) and oxygen (O 2 )

[0020] There are no particular limitations on the photocatalytic material, so long as it is a material that absorbs light and excites electrons. For example, TiO 2 , SrTiO 3 , SrTiO 2 N, BaTaO 2 N, NaTaO 3 , WO 3 , ZnO, Fe 2 O 3 , CuO, Ta 2 O 5 , Bi 2 O 3 , SnO 2 , BiVO 4 , Y 2 Ti 2 O 5 S 2 To promote the reaction, Photocatalytic materialsThe surface may be appropriately modified with a material that can act as a promoter. Representative promoter materials include, for example, Pt, Ru, Rh, Au, etc. The photocatalyst material may be supported by a substrate. The photocatalytic material may be in the form of a powder mixture, a compact, or a sheet that functions as an anode or a cathode. Also, a photoelectrode structure in which the anode and cathode are separated may be used.

[0021] The gas generated by the photocatalytic decomposition unit 103 (generated gas: H 2 Or O 2 ) can be recovered through a recovery port 104. Although not shown, it is desirable to provide a mechanism for trapping excess water vapor, such as a Liebig condenser, at the end of the recovery port 104. After trapping the water vapor, the generated gas is pumped to a pipe 108 by a pump 109a. Inside Transfer and H 2 Or O 2 The gas other than H is separated and the exhaust gas 110 is exhausted. 2 Or O 2 It is also desirable to have a mechanism for removing salt that has partially precipitated in the steam generating section 102 by using trapped fresh water.

[0022] According to the photocatalytic decomposition device 100 of the present embodiment described above, in the steam generating section 102 having the pores 120, ,light 105 is converted into heat to turn water into steam, and the steam or the fresh water produced by cooling the steam is used as a photocatalyst. Decomposition By performing water decomposition by photocatalytic decomposition unit 103, water can be decomposed more efficiently than in the past. Since the water in water layer 107 is steamed once before being decomposed in photocatalytic decomposition unit 103, in the case of seawater, for example, the generation of chloride ions and hypochlorous acid in photocatalytic decomposition unit 103 can be suppressed, and seawater can be decomposed continuously without generating harmful and toxic substances contained in seawater.

[0023] The photocatalytic decomposition device 100 of this embodiment decomposes water to produce H 2 and O 2It is not limited to applications that generate only CO. 2 or nitrogen oxides (NO x ) and use them for the reduction reaction at the cathode. In that case, the gas species to be reacted can be introduced into the container by providing a separate gas inlet. It can also be used for the synthesis of organic compounds such as formic acid, ethanol, methanol, and methyl. EXAMPLES

[0024] Fig. 2 is a schematic diagram of a photocatalytic decomposition device of Example 2. Fig. 2 illustrates a housing 201 of a photocatalytic decomposition device 200 and its internal structure. As shown in Fig. 2, in this example, an inclined portion 205 inclined in the horizontal direction is provided on the upper surface of the housing 201, so that the water vapor generated in the steam generating portion 202 flows along the inclined portion 205 and is cooled to become fresh water, which is then introduced into the photocatalytic decomposition portion 203. The fresh water introduced into the photocatalytic decomposition portion 203 is decomposed by a photocatalytic reaction in the same manner as the water vapor.

[0025] With this configuration, minutes The supply of water to be decomposed can be performed more efficiently than by supplying water vapor to the photocatalytic decomposition section 203, and the device as a whole can perform photocatalytic decomposition more efficiently than in the first embodiment. EXAMPLES

[0026] FIG. 3 is a schematic diagram of a photocatalytic decomposition device of Example 3. FIG. 3 illustrates a housing 301 of a photocatalytic decomposition device 300 and its internal structure. As shown in FIG. 3, in this example, a black body section 305 that absorbs light supplied from a light source and increases in temperature is provided on the upper surface of the steam generation section 302. The black body section 305 is made of a material that absorbs heat more efficiently than the steam generation section 302. This configuration allows water from the water layer to be more efficiently decomposed. Fever In addition, the device as a whole can perform photocatalytic decomposition more efficiently than in Example 1. EXAMPLES

[0027] FIG. 4 is a schematic diagram of a photocatalytic decomposition device of Example 4. FIG. 4 illustrates a housing 401 of a photocatalytic decomposition device 400 and its internal structure. As shown in FIG. 4, in this example, a photocatalytic decomposition unit 403 is provided so as to be in contact with the surface of the housing 401 on which light is incident. In the photocatalytic decomposition unit 403, a base material that holds a catalyst is made of a material that transmits at least infrared light. The transmitted infrared light is absorbed by the steam generation unit 402, and increases the temperature of the steam generation unit 402. The ultraviolet light and visible light that do not transmit through the photocatalytic decomposition unit 403 are absorbed by the photocatalytic material of the photocatalytic decomposition unit 403, and are used in the photocatalytic reaction, contributing to water decomposition.

[0028] With this configuration, the light from the light source is used for heating water and for catalyst By separating the excitation light into two, heat generation and decomposition are more efficient, and the device as a whole can perform photocatalytic decomposition more efficiently than in Example 1.

[0029] As described above, it has been shown that the present invention can provide a photocatalytic decomposition device that can efficiently supply and vaporize water to be decomposed by the photocatalyst.

[0030] The present invention is not limited to the above-described embodiments, and includes various modified examples. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the configurations described. It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0031] 100, 200, 300, 400... photocatalytic decomposition device, 101, 201, 301, 401... housing, 102, 202, 302, 402... steam generating section, 103, 203, 303, 403... photocatalytic decomposition section, 104... recovery port, 105 …light, 106...steam, 107...water layer, 108...piping, 109a, 109b...pump, 110...exhaust gas, 120...hole, 205...inclined portion, 305...black body portion.

Claims

1. A decomposition device using a photocatalyst, a steam generating unit that has holes for sucking up water and absorbs light supplied from a light source to generate heat; A photocatalytic decomposition device comprising: a photocatalytic decomposition section in which the steam generated in the steam generation section is in contact with the photocatalyst and in which the photocatalyst is irradiated with light supplied from the light source.

2. 2. The photocatalytic decomposition device according to claim 1, wherein the steam generating section is in contact with water, and the pores suck up water by capillary action.

3. 2. The photocatalytic decomposition apparatus according to claim 1, wherein the porosity of the steam generating section is 10% by volume or more and 90% by volume or less.

4. 2. The photocatalytic decomposition device according to claim 1, wherein an inclined portion is provided on an inner surface of a housing that houses the steam generating section and the photocatalytic decomposition section, A photocatalytic decomposition device having a configuration in which steam or water generated in the steam generating section is supplied to the photocatalytic decomposition section through the inclined section.

5. 2. The photocatalytic decomposition device according to claim 1, further comprising a black body section on an upper surface of the steam generating section, the black body section absorbing more heat than the steam generating section.

6. 2. The photocatalytic decomposition device according to claim 1, wherein the photocatalytic decomposition section is provided on a surface of the housing on which the light is incident, and the light transmitted through the photocatalytic decomposition section is supplied to the steam generation section.

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