KR20060057186A - A hydrogen generator using photocatalyst and preparation method of hydrogen using the same - Google Patents

Abstract

The present invention is a light source for irradiating light to the photocatalytic reactor (2), the water is filled and the wire is contacted to the outside photocatalyst reactor (2), a power supply member 14 for supplying charge to the wire, the photocatalytic reactor (2) Located at one side of the inside to absorb light from the light source to separate the water into oxygen and hydrogen ions photocatalyst electrode (8), installed on one side of the photocatalytic reactor (2) to discharge oxygen produced by the photocatalyst electrode (8) The oxygen outlet 18 to be connected to one side of the photocatalytic reactor 2, the separation membrane 6 for passing hydrogen ions generated by the photocatalytic reaction to the hydrogen generating reactor 4, hydrogen ions from the separation membrane 6 The introduced hydrogen generating reactor (4), provided on one side of the inside of the hydrogen generating reactor (4), the positive electrode 10 for producing hydrogen by combining the introduced hydrogen ions and electrons and one side of the hydrogen generating reactor (4) Install on Using a photocatalyst comprising a hydrogen discharge port 20 for discharging the generated hydrogen and a circuit providing a movement path for moving electrons generated in the photocatalytic electrode 8 to the positive electrode 10 of the hydrogen generation reactor 4. Provided is a hydrogen production apparatus.

According to the present invention, since hydrogen is produced using a light source as an energy source, not only can be operated at low cost, but also high-purity hydrogen can be produced without generating by-products such as carbon dioxide and carbon monoxide generated in a hydrogen production method using a hydrocarbon. It works.

Photocatalyst, oxidation reaction, electron, separator, electrode

Description

Hydrogen Generator Using Photocatalyst and Preparation Method of Hydrogen Using the Same}

1 is a block diagram showing an apparatus for producing hydrogen using a photocatalyst according to the present invention,

2 is a block diagram showing a hydrogen production apparatus using a photocatalyst of another embodiment according to the present invention.

<Description of the symbols for the main parts of the drawings>

2 photocatalytic reactor 4 hydrogen generating reactor

6 separator 8 photocatalytic electrode

10: positive electrode 12: first switch

12 ': second switch 12 ": third switch

14 power supply member 16 electronic storage member

18: oxygen outlet 20: hydrogen outlet

22: hydrogen ion outlet 24: hydrogen ion inlet

26: first wire 28: second wire

30: third wire 32: coil

The present invention relates to a method for producing hydrogen using a photocatalyst, and more particularly to a method of producing hydrogen by irradiating light to an electrode having a photocatalytic activity, separating water into hydrogen ions and oxygen, and adding electrons to the separated hydrogen ions. It is about.

Hydrogen is used as a raw material for ammonia, methanol, etc., and is an essential raw material for the hydrogenation reaction to produce a saturated compound. It is essential for the immobilization of carbon dioxide, which is the main cause of the recent global warming problem. In addition, hydrogen is one of the clean alternatives, and is expected to be a future energy source to replace the current fossil fuel.

Conventional methods for producing hydrogen described above include a method of producing hydrogen by reforming fossil fuels such as naphtha and natural gas, a method of contacting iron with steam at high temperatures, and a method of reacting alkali metals with water.

In particular, a method of reforming a hydrocarbon fuel such as methane gas or methanol through a thermochemical reaction produces hydrogen using a catalyst such as Cu—Zn at a temperature of 200 ° C. or higher. The product of the reforming reaction contains a large amount of compounds such as carbon monoxide and carbon dioxide in addition to hydrogen, and proceeds at a high temperature and is an endothermic reaction, and thus various kinds of heat insulation, heat exchange for cooling the generated gas, gas supply, and pressure adjustment are required. The disadvantage is that the size of the reactor system is huge due to the installation of the auxiliary device.

On the other hand, most of the hydrogen in nature exists in the form of water and other inorganic compounds, and the hydrogen in the gaseous state is very low in the atmosphere due to its low specific gravity, and the hydrogen in the form of the inorganic compound is pure In addition, the separation is not only technically difficult, but even if the technical separation is possible, the separation costs a lot, and thus the economic efficiency is low. Therefore, a technique for effectively producing hydrogen from water will be a very meaningful task.

The representative method for producing hydrogen from the above-mentioned water can be referred to as electrolysis. In the case of the electrolysis, there is an advantage in that hydrogen can be immediately produced as needed, but due to excessive lifetime due to the lifetime of the electrode and the power used. There is a problem that occurs.

Recently, in order to solve the above-mentioned problems, there is a growing interest in a method of producing hydrogen using a photocatalyst, which is one of advanced oxidation techniques.

The photocatalytic reaction generates electrons and holes when light energy of more than a band gap energy is irradiated to the photocatalyst, and the gas phase or the photocatalyst is brought into contact with the photocatalyst surface by the strong oxidizing power of radicals (· OH) generated by the holes. It refers to a reaction in which a liquid substance is decomposed.

As a method for producing hydrogen using the photocatalyst described above, Japanese Patent Laid-Open No. 62-19045 is characterized in that hydrogen is generated from the photolysis reaction of an aqueous solution of Na ₂ S using a rare earth element compound as a photocatalyst. It has the advantage of showing activity. In addition, Japanese Patent Application Laid-Open No. 63-107815 is characterized by generating hydrogen from photolysis of methanol aqueous solution by using a composite oxide of niobium and alkaline earth metal as a photocatalyst, which also shows the activity of the catalyst in visible light. There is an advantage. However, the hydrogen production method according to the above technique has a problem in that the amount of hydrogen produced is very small, about 10 mg / 0.5 g hr.

On the other hand, Korean Patent Publication No. 1997-0009559 discloses a method of generating hydrogen by irradiating ultraviolet light to an aqueous solution mixed with an accelerator, such as alcohol, formaldehyde and photocatalyst, which is harmless and can generate hydrogen at room temperature Although there is an advantage, since oxygen-containing organic matter is used as a hydrogen generation accelerator, there is a problem that it is difficult to reuse the oxygen-containing organic matter after participating in the reaction.

In order to solve the above problems, Korean Patent Publication No. 1997-014835 discloses a hydrogen production method that is harmless to the environment by changing the photocatalyst used and does not use an oxygen-containing organic accelerator.

In addition, Korean Patent Publication No. 2000-0019204 discloses a photocatalyst by irradiating light with a photocatalyst while contacting, suspending and stirring the photocatalyst with Na ₂ S as an electron donor and NaH ₂ PO ₂ as a reducing agent or primary or secondary distilled water or simply pretreated water. A method of separating hydrogen from water by causing a reaction is disclosed. However, the process is difficult to operate because it is necessary to control the temperature and pressure while controlling the additives in an appropriate molar number for the oxidation reaction generated by the photocatalyst and the reduction reaction for separating the oxidized water into hydrogen and oxygen. There is such a problem.

The present invention is to solve the above problems, after the addition of water and photocatalyst to the coiled photocatalyst reactor to the outside and irradiated with light to the reactor to separate the hydrogen from the water, the hydrogen generated separated hydrogen ion having an electrode It moves to the reactor, the water is separated into hydrogen, the generated oxygen is discharged to the outside, and the electron is moved to the electrode installed in the hydrogen generating reactor along the wire connected with the photocatalyst to combine with the hydrogen ions introduced into the hydrogen generating reactor to hydrogen There is a technical problem in manufacturing the.

In one aspect, the present invention is a light source for irradiating light to the photocatalyst reactor, filled with water and the wire is contacted to the outside photocatalyst reactor, a power supply member for supplying charge to the wire, located on one side inside the photocatalytic reactor from the light source A photocatalyst electrode that absorbs light to separate water into oxygen and hydrogen ions, an oxygen discharge port installed at one side of the photocatalytic reactor to discharge oxygen produced by the photocatalytic electrode, and connected to one side of the photocatalytic reactor to perform photocatalytic reaction. A separator for passing the generated hydrogen ions to a hydrogen generating reactor, a hydrogen generating reactor for introducing hydrogen ions from the separator, a positive electrode provided at one side of the hydrogen generating reactor to combine hydrogen and electrons introduced therein to produce hydrogen; Hydrogen generated by being installed on one side of the hydrogen generation reactor Shipping provides a hydrogen-using the photocatalyst including a circuit for providing a route for moving the electrons generated from the hydrogen outlet port and the photocatalyst electrode to the positive electrode of the hydrogen generating reactor.

In another aspect, the present invention is irradiated with light to the photocatalytic electrode provided on one side of the photocatalytic reactor filled with water and the coil is wound outside to separate the water into oxygen and hydrogen ions, the separated oxygen is the photocatalytic reactor Discharged to the outside, and the separated hydrogen ions pass through the membrane and are transferred to the hydrogen generating reactor, and the water is separated into oxygen and hydrogen ions, and the generated electrons are moved along the wire connected to the photocatalyst electrode, so that one side inside the hydrogen generating reactor It provides a method for producing hydrogen using a photocatalyst comprising moving to the positive electrode provided in the combined hydrogen ions passing through the separator and introduced into the hydrogen generating reactor to generate hydrogen.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing a hydrogen production apparatus using a photocatalyst according to the present invention, Figure 2 is shown as a block diagram showing a hydrogen production apparatus using a photocatalyst of another embodiment according to the present invention.

1 and 2, the hydrogen production apparatus using a photocatalyst according to the present invention is a light source for irradiating light in the ultraviolet or visible light region to the photocatalytic reactor 2, a photocatalyst for separating water into oxygen and hydrogen ions Separation membrane (6), which is connected to the reactor (2) and the photocatalytic reactor (2) and the hydrogen generating reactor (4) to pass the hydrogen ions generated in the photocatalytic reactor (2) to the hydrogen generating reactor (4), the Hydrogen generating reactor (4) for generating hydrogen by reacting hydrogen ions introduced from the membrane (6) and a circuit connected to the hydrogen generating reactor (4) and the photocatalytic reactor (2) to provide a movement path of electrons Consists of

Here, the photocatalytic reactor 2 is provided with a photocatalytic electrode 8 made of a material having a photocatalytic activity or coated with a photocatalytic activity therein. In addition, a first wire 26 is provided at one upper end of the photocatalytic electrode 8 to provide a movement path of electrons generated at the photocatalytic electrode 8, and a photocatalytic reaction is performed at the upper end of the photocatalytic reactor 2. Oxygen outlet (18) for discharging oxygen separated from the water is provided, the hydrogen ion separated from the water by the photocatalytic reaction to the hydrogen ion outlet 22 formed on one side of the photocatalytic reactor (2) Discharged. In this case, the hydrogen ion outlet 22 is connected to the separator 6, and the separator 6 may pass only hydrogen ions present in the photocatalytic reactor 2.

On the other hand, the photocatalytic reactor 2 is composed of a material that can pass the light for the photocatalytic oxidation reaction using the light of the ultraviolet or visible light region as an energy source, the available material is a material that can pass the light You can use any of them, and it is recommended to use glass, transparent plastic, crystal, and the like.

In addition, the third wire 30 is in contact with the outside of the photocatalytic reactor 2 according to the present invention, the third wire 30 is a power supply member connected to one side of the third wire 30 When power is applied from (14), a negative charge is applied to the inner outer wall surface of the photocatalytic reactor (2).

At this time, the outer wall surface of the photocatalytic reactor 2, the coil (2) is wound as needed, the coil (2) wound on the outside of the photocatalytic reactor 2, one end of the third wire ( 30 is connected to one end of the terminal so that when a power is applied from the power supply member 14, a negative charge can be applied to the inner outer wall of the photocatalytic reactor 2.

The photocatalytic electrode 8 according to the present invention may use any material that exhibits catalytic activity by absorbing light energy and may move electrons, and the photocatalyst has a strong oxidative force generated by the catalytic activity, so that water is hydrogen ion. Oxidative decomposition with and oxygen. In this case, as the material for inducing the photocatalytic reaction, TiO ₂ , ZnO ₂ , ZnO, SrTiO ₃ , CdS, GaP, InP, GaAs, BaTiO ₃ , KNbO ₃ , Fe ₂ O ₃ , Ta ₂ O ₅ , WO ₃ , SnO ₂ , Bi ₂ O ₃ , NiO, Cu ₂ O, SiO, SiO ₂ , MoS ₂ , InPb, RuO ₂ , CeO ₂ , and the like, and the photocatalyst includes Pt, Rh, Ag, Cu, Sn, Ni, Fe Metals such as these and metal oxides thereof may be added, or a material having the photocatalytic activity may be coated on a conductor material having no photocatalytic activity.

The separator 6 according to the present invention provides a path for passing hydrogen ions generated in the photocatalytic reactor 2 to the hydrogen generating reactor 4, which is commonly referred to as a membrane. 6) may be used in any form, such as hollow fiber membrane, reverse osmosis membrane, ion exchange membrane. The separator 6 is connected to a hydrogen ion outlet 22 through which hydrogen ions generated in the photocatalytic reactor 2 are discharged, and the hydrogen ion outlet 22 easily discharges hydrogen ions present in the liquid phase. For this purpose, it is preferable to be installed lower than the water level filled in the photocatalytic reactor 2.

On the other hand, the hydrogen generation reactor (4) is provided with a positive electrode (10) connected to the wires so that the electrons flow into the inside, the hydrogen ion inlet (24) so that the hydrogen ions discharged from the separator 6 is introduced It is connected to the separator 6, the electrons flowing into the positive electrode 10 and the hydrogen ions flowing from the separator 6 is combined to produce hydrogen, and the hydrogen outlet for discharging the produced hydrogen (20) ) Is provided on one side of the hydrogen generation reactor (4).

Herein, the positive electrode 10 may be any conductor as long as it is an electrically conductive conductor, and preferably platinum.

On the other hand, the circuit connected to the hydrogen generating reactor 4 and the photocatalytic reactor 2 according to the present invention to provide a path for the movement of electrons is connected to the photocatalytic electrode 8 to provide a path for the electrons generated from the photocatalytic reaction. A first switch 12 to be provided and connected to an end of the first wire 26 so as to connect the first wire 26 to the third wire 30; The second electric wire 28 connected to the positive electrode 10 of the hydrogen generation reactor 4, is connected to the end of the second electric wire 28 to connect the second electric wire 28 with the third electric wire 30 A second switch 12 ', which allows one end to be in contact with the first switch 12 or the second switch 12', and the other end opposite to the one end is connected to an outer wall surface of the photocatalytic reactor. Third electric wire 30 in contact and a third electric wire in contact with the first switch 12 or the second switch 12 ′. An electronic storage element 16, the third switch (12 ") from the end of the 30 consists installed sequentially connected.

Here, when power is applied to the power supply member 14, when the third switch 12 "is turned on and the current flows along the third wire 30, the first wire 26 The first switch 12 provided at the end of the switch is turned on and the second switch 12 'provided at the end of the second electric wire 28 is turned off to thereby turn off the photocatalytic reactor 2. Induces and stores electrons generated from the photocatalytic electrode 8 into the electron storage member 16. When the third switch 12 ″ is turned off, the second switch is provided at the end of the second wire 28. The electrons stored in the electronic storage member 16 are stored in the second electric wire by turning on the 12 'and turning the first switch 12 provided at the end of the first electric wire 26 off. It is moved to the positive electrode 10 which is connected to one end of the 28.

At this time, the operation of the first switch 12, the second switch 12 ′ and the third switch 12 ″ is on-off depending on the time or the amount of electrons generated in the photocatalytic reactor 2. ) To control.

Looking at the operation method of the hydrogen production apparatus using a photocatalyst according to the present invention having the configuration as described above are as follows.

First, the photocatalyst reactor 2 filled with water is irradiated with light such as ultraviolet rays and / or visible light to separate water into oxygen and hydrogen ions on the surface of the photocatalyst electrode 8. At this time, the first switch 12 provided at the end of the first electric wire 26 and the third switch 30 provided at one side of the third electric wire 30 are turned on and then the power supply member ( The third electric wire 30 connected to the third electric wire 30 in contact with the outside of the photocatalytic reactor 2, preferably the third electric wire connected to the coil 32 wrapped around the photocatalytic reactor 2 by applying power to A negative charge is applied to the outer wall surface of the photocatalytic reactor 2 by supplying a current to 30).

Here, the coil 32, which is connected to one end of the third wire 30, preferably the third wire 30, is dissociated by the oxidation reaction generated at the photocatalytic electrode 8 of the photocatalytic reactor 2. By pulling the hydrogen ions having a positive charge out of the oxygen and hydrogen ions to the outer wall surface of the photocatalytic reactor 2 by an electrical attraction force, the oxygen and hydrogen ions are recombined to prevent water from being recombined.

On the other hand, the oxygen separated by the photocatalyst electrode 8 is discharged to the outside through the oxygen discharge port 18 provided on one side of the photocatalytic reactor 2, the hydrogen ion on the opposite side of the oxygen discharge port 18 The hydrogen ion outlet 22 passes through the separator 6 through which only hydrogen ions pass, and then moves to the hydrogen generating reactor 4. In addition, electrons formed by the oxidation reaction generated in the photocatalytic electrode 8 pass through the first wire 26 and the first switch 12 connected to the photocatalytic electrode 8 to form a third wire 30. It is stored as the electronic storage member 16 provided on one side of.

Then, after a predetermined time has elapsed, the third switch 12 ″ provided on one side of the third wire 30 and the first switch 12 provided at the end of the first wire 26 are turned off. Then, the second switch 12 'provided at one end of the second wire 28 is brought into contact with the third wire 30 to keep the second switch 12' on.

At this time, as the second switch 12 ′ is kept in an on state, electrons stored in the electronic storage member 16 of the third wire 30 are transferred to the second switch 12 ′ and the second switch 12. ') Is passed through the second wire 28 connected to the positive electrode 10 of the hydrogen-generation reactor (4).

Meanwhile, in the hydrogen generation reactor 40, hydrogen ions passing through the separator 6 and electrons passing through the second switch 12 ′ and the second electric wire 28 are introduced to form hydrogen on the surface of the positive electrode 10. The generated hydrogen is discharged through the hydrogen discharge port 20.

As described above, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the exemplary embodiments described above are to be understood as illustrative in all respects and not as restrictive. The scope of the present invention should be construed that all changes or modifications derived from the meaning and scope of the appended claims and their equivalents, rather than the detailed description, are included in the scope of the present invention.

The present invention is to produce hydrogen by separating oxygen and hydrogen ions from water by using an oxidation reaction of the photocatalyst and supplying electrons to the separated hydrogen ions, which can be operated at low cost since hydrogen is produced using a light source as an energy source. In addition, there is an effect that can produce high purity hydrogen without generating by-products such as carbon dioxide and carbon monoxide generated in the hydrogen production method using a hydrocarbon.

Claims (4)

Light source for irradiating light to the photocatalytic reactor, water is filled and the wire is contacted to the outside to the photocatalyst reactor, a power supply member for supplying charge to the wire, located on one side inside the photocatalytic reactor to absorb light from the light source to oxygen And a photocatalyst electrode separating into hydrogen ions, an oxygen outlet installed at one side of the photocatalytic reactor to discharge oxygen produced by the photocatalytic electrode, and connected to one side of the photocatalytic reactor to generate hydrogen ions generated by the photocatalytic reaction. Separation membrane to pass through the reactor, a hydrogen generation reactor in which hydrogen ions are introduced from the separator, provided on one side of the hydrogen generation reactor, the positive electrode to combine the introduced hydrogen ions and electrons to produce hydrogen and on one side of the hydrogen generation reactor Hydrogen outlet for discharging hydrogen generated and installed An apparatus for producing hydrogen using a photocatalyst comprising a circuit providing a movement path for moving electrons generated from a photocatalyst electrode to a positive electrode of a hydrogen generation reactor. The method of claim 1, A first wire that is connected to the photocatalyst electrode to provide a path of movement of electrons resulting from the photocatalytic reaction, and is connected to an end of the first wire to connect the first wire to a third wire 1 switch, a second wire connected to the positive electrode of the hydrogen generation reactor, a second switch connected to the end of the second wire so as to connect the second wire with a third wire, one end is the first end Electron storage from a third wire in contact with a switch or a second switch, the other end facing the one end of the third wire contacting the outer wall surface of the photocatalytic reactor, and a third wire contacting the first switch or the second switch Hydrogen production apparatus using a photocatalyst comprising a member and the third switch is connected in sequence. The method according to claim 1 or 2, The photocatalyst reactor is a coil wound around the outside, the hydrogen production apparatus using a photocatalyst comprising a wire connected to one side of the coil. The light is irradiated to the photocatalyst electrode provided on one side of the photocatalytic reactor filled with water and the coil is wound outside to separate water into oxygen and hydrogen ions, and the separated oxygen is discharged to the outside of the photocatalytic reactor. Hydrogen ions pass through a separator and are transferred to a hydrogen generating reactor, and water is separated into oxygen and hydrogen ions, and the generated electrons are moved along a wire connected to the photocatalyst electrode and moved to a positive electrode provided at one side of the hydrogen generating reactor. A method of producing hydrogen using a photocatalyst comprising generating hydrogen by combining with hydrogen ions introduced into the hydrogen generating reactor through a separator.

Images