TWI465608B - Hydrogen generating method and hydrogen generating appartus - Google Patents

Description

Hydrogen generation method and hydrogen generation device

The present invention relates to a hydrogen generating method using an electrode reaction and a hydrogen generating device, and is particularly suitable for use as a technique for generating electricity by supplying hydrogen to a fuel cell.

Conventionally, a hydrogen generating agent that supplies water and generates hydrogen has a material mainly composed of a metal such as iron or aluminum. Among them, in particular, a hydrogen generating method using a metal such as aluminum has an advantage that the raw material cost of the hydrogen generating agent is low. However, when aluminum is used, if the particles are not made small at room temperature, the reactivity is low, and when a reaction with water occurs, a film is formed on the surface of the aluminum, and the reaction becomes difficult to proceed.

On the other hand, Patent Document 1 discloses a hydrogen generation method in which magnesium is used as an anode, an inactive metal is used as a cathode, and two electrodes are immersed in salt water to form a battery, and the hydrogen production is adjusted by controlling the current of the two electrodes.

Further, Patent Document 2 discloses a method for producing hydrogen by using magnesium or aluminum as an anode and an inactive metal as a cathode, and immersing the two electrodes in an aqueous electrolyte solution to perform electrolysis of water to generate hydrogen.

Further, Patent Document 3 discloses an apparatus which forms an electrolytic separator by a non-woven fabric when water is generated by electrolysis of water. This non-woven fabric is disposed at a position away from the electrodes on both sides.

[Previous Technical Literature]

[Patent Literature]

[Patent Document 1] US Patent No. 3892653

[Patent Document 2] US Publication No. 2004/9392

[Patent Document 3] Japanese Patent Laid-Open No. Hei 10-235357

However, in the hydrogen generation method described in Patent Document 1, since the metal constituting the cathode does not react at the cathode, there is a problem that the hydrogen production is reduced. Further, in the hydrogen generation method described in Patent Document 2, the metal constituting the cathode does not react. Therefore, in order to secure a sufficient hydrogen production, it is necessary to increase the power for supplying electricity.

As a result, in the hydrogen generation method using the electrolysis method, it is impossible to continue the power generation by causing the fuel cell to generate electricity by the generated hydrogen while electrolyzing with the electric power. This is because the power generated by the fuel cell will exceed the power consumed by the electrolysis, that is, the power balance cannot be achieved.

On the other hand, when a non-woven fabric or the like is used as the electrolytic separator, as described in Patent Document 3, it is found that when the non-woven fabric or the like is disposed at a constant interval from the electrode, the power consumption during hydrogen generation increases, and the same as described above. It is difficult to make the electricity revenue and expenditure positive.

Accordingly, an object of the present invention is to provide a hydrogen generating method and a hydrogen generating apparatus which can efficiently carry out hydrogen generation reaction at both electrodes and carry out the reaction for a long period of time.

As a result of intensive studies on the hydrogen generation method using electrolysis reaction of water, the inventors of the present invention found that the hydrogen generation reaction between the electrodes is made efficient by bringing the porous body into contact with the electrode and interposed between the two electrodes. Hydrogen production can be carried out for a long period of time, and the present invention is completed.

That is, the method for producing hydrogen according to the present invention is characterized in that a porous body is brought into contact with an anode and a cathode containing magnesium or aluminum and interposed between the two electrodes, and the porous body is maintained in an aqueous electrolyte solution to energize the two electrodes. Or applying a voltage to the aforementioned two poles to generate hydrogen. In this case, the cathode system is preferably magnesium or aluminum.

According to the hydrogen generating method of the present invention, since the porous body is brought into contact with the electrode and interposed between the two electrodes, the acidity exhibited by the reaction at the anode can be inferred as compared with the case where the porous body is not in contact with the porous body. The alkalinity exhibited by the reaction at the cathode is easily maintained, and the self-reaction (hydrogen generation reaction) of the electrode is promoted under acidic conditions, and the hydrogen generation reaction proceeds efficiently. In the case where the cathode contains magnesium or aluminum, it is further inferred that at the cathode, the self-reaction (hydrogen generation reaction) of the electrode is promoted under alkaline conditions, and the hydrogen generation reaction proceeds efficiently. Further, it is also inferred that components (for example, metal hydroxides) formed by the reaction do not adhere to the surface of the electrode, but are contained in the pores of the porous body, so that reaction inhibition by by-products can be suppressed, and it is possible for a long time. A hydrogen generation reaction is carried out. As a result, a hydrogen generation method can be provided, and the hydrogen generation reaction at both electrodes can be performed efficiently and for a long period of time.

In the present invention, the porous system is preferably a porous body having a porosity of 30 to 99.9%. If the porosity is in this range, the acidity which is exhibited by the reaction at the anode is more easily maintained with the alkalinity which is exhibited by the reaction at the cathode, and the viewpoint of the reaction hindrance by the by-product is suppressed. Also suitable.

In the present invention, the porous system is preferably a porous body composed of an elastically deformable sponge resin. When an elastically deformable sponge-like resin is used, the contact with the electrode surface is easily made uniform by the elastic restoring force, and the above-described effects can be more stably exhibited.

In the present invention, the anode and the cathode are formed in a plate shape, and it is preferable that the porous body is interposed between the two electrodes. Thereby, a thin electrode unit can be formed, and the area of the electrode disposed in a certain volume can be increased, that is, the bulk density of the electrode unit can be increased.

In the present invention, a porous body is also present around the two poles, and the porous system is preferably integrated continuously with the porous body interposed between the two electrodes. According to this configuration, the aqueous electrolyte solution can be efficiently supplied from the surrounding porous body to the porous body interposed between the electrodes, and the reaction can be efficiently carried out.

On the other hand, the hydrogen generator of the present invention includes: an anode including a magnesium or aluminum, a cathode, a porous body disposed in contact with the two electrodes and holding the aqueous electrolyte solution, and energizing or applying the two electrodes to the two electrodes. The means of voltage. In this case, the cathode system is preferably magnesium or aluminum.

According to the hydrogen generating apparatus of the present invention, since the electrode is brought into contact with the porous body and interposed between the two electrodes, the acidity exhibited by the reaction at the anode can be inferred as compared with the case where the porous body is not in contact with the porous body. The alkalinity exhibited by the reaction at the cathode is easily maintained, and the self-reaction (hydrogen generation reaction) of the electrode is promoted under acidic conditions, and the hydrogen generation reaction proceeds efficiently. In the case where the cathode contains magnesium or aluminum, it is further inferred that at the cathode, the self-reaction (hydrogen generation reaction) of the electrode is promoted under alkaline conditions, and the hydrogen generation reaction proceeds efficiently. Further, it is also inferred that components (for example, metal hydroxides) formed by the reaction do not adhere to the surface of the electrode, but are contained in the pores of the porous body, so that reaction inhibition by by-products can be suppressed, and it is possible for a long time. A hydrogen generation reaction is carried out. As a result, it is possible to provide a hydrogen generating device which can efficiently carry out hydrogen generation reaction at both electrodes and carry out the reaction for a long period of time.

In the hydrogen production method of the present invention, the porous body is brought into contact with the anode or cathode containing magnesium or aluminum and interposed between the two electrodes, and the porous body is held in the state of the electrolyte solution, and the two electrodes are energized or applied to the two electrodes. The voltage causes hydrogen to be generated. Here, the anode refers to a pole that emits electrons as the electrode reacts, and the cathode refers to a pole that accepts electrons as the electrode reacts.

In the cathode, in addition to metals having a low standard electrode potential such as magnesium, aluminum, zinc, iron, nickel, tin, or lead, a noble metal such as platinum or gold can be used. However, from the viewpoint of efficiency or purity of hydrogen production, magnesium, aluminum, nickel, zinc, iron, silver, platinum, and gold are preferred.

When a voltage is applied to the two poles, a combination of a magnesium-containing anode and a magnesium-containing cathode, or an aluminum-containing anode and an aluminum-containing cathode is preferred, and a magnesium-containing anode is combined with an aluminum-containing cathode or contains aluminum. The combination of the anode and the magnesium-containing cathode produces hydrogen.

In the case where the two electrodes are energized, a combination of a magnesium-containing anode and an aluminum-containing cathode, or a combination of a magnesium-containing anode and a nickel-containing cathode is preferred. Since the potential difference is almost or completely not generated due to the combination of the same metals, it is preferable to apply a voltage to the two electrodes in the above manner.

In the present invention, both the electrode reaction accompanying electron transfer and the self reaction (spontaneous reaction) without accompanying electron transfer occur. Since the electrode reaction accompanying electron transfer is accompanied by consumption of electric power or consumption of electric power generated by the battery, it is important to increase the ratio of the self-reaction in order to efficiently carry out the hydrogen generation reaction between the two electrodes. These reactions are as described below.

For example, in the case of two extremely aluminum, it can be estimated that it will occur at the anode: Al+3OH ^- →Al(OH) ₃ +3e ^- (electrolysis of water), and 2Al+6H ₂ O→2Al(OH) ₃ +3H ₂ ↑ (self-reaction caused by Al activation).

In addition, it can be estimated that it will occur at the cathode: 2H ⁺ +2e ^- → H ₂ ↑ (electrolysis of water), and 2Al + 6H ₂ O → 2Al(OH) ₃ + 3H ₂ ↑ (self-reaction caused by Al activation) ).

In the case of using magnesium, it can be estimated that it will occur at the anode: Mg+2OH ^- →Mg(OH) ₂ +2e ^- (electrolysis of water), Mg+2H ₂ O→Mg(OH) ₂ +H ₂ ↑(Mg Self-reaction caused by activation).

In the case of use in a cathode, it can be estimated that the same self-reaction occurs, as well as the same water electrolysis reaction as in the case of aluminum.

Along with the above reaction, the acidity is increased in the vicinity of the anode due to the consumption of hydroxide ions, and the alkalinity is increased in the vicinity of the cathode due to the consumption of hydrogen ions. In the case where the porous body is not in contact with the electrode, local acidity or alkalinity becomes difficult to maintain. In particular, in the case where only the porous body is present and only the electrolyte liquid is present, the neutralization phenomenon caused by the diffusion causes the acidity or the alkalinity to be maintained.

Since hydrogen generation due to self-reaction of aluminum proceeds under alkaline conditions and acidic conditions, maintaining the acidity and alkalinity in such a manner increases the efficiency of the hydrogen generation reaction. In addition, since hydrogen generation due to the self-reaction of magnesium is advantageous under acidic conditions, maintaining acidity increases the efficiency of hydrogen generation reaction. From this point of view, magnesium is preferably used for the anode.

In the case of an electrode containing aluminum, the purity of aluminum is preferably 90% or more, and preferably 99 to 99.9%. Examples of other elements contained in the electrode include Mg, Mn, Zn, Cu, Si, Fe, Ti, Cr, V, Bi, Pb, Zr, B, and the like.

In the case of the electrode containing magnesium, the purity of magnesium is preferably 90% or more, and preferably 96 to 99.99%. Examples of other elements contained in the electrode include Al, Mn, Zn, Cu, Si, Fe, Ti, Cr, Ni, Ca, Zr, and Be.

The shape of the anode and/or the cathode (hereinafter referred to as "electrode") may be any of a columnar shape, a plate shape, a block shape, and the like, and in order to make the electrode area wide, it is preferably a plate shape. In the case of a plate shape, it may be a perforated type such as a punched metal, a type having a slit like a comb electrode, a mesh type, a non-woven fabric, or the like. The plate-shaped electrode may be formed into a cylindrical shape, a rectangular tube shape, a spiral shape, a zigzag shape, a folded shape, or the like in addition to a flat plate shape.

The anode or the cathode may be provided in a single number or may be provided in plurality. In the case where a plurality of devices are provided, the circuit aspects may be connected in series or in parallel, or both may be used in combination.

In the case of using aluminum, the thickness of the electrode is preferably 0.03 to 5 mm, and preferably 0.1 to 1 mm, from the viewpoint of ensuring sufficient hydrogen production and increasing the metal reaction rate. The thickness of the electrode in the case of using magnesium is preferably from 0.3 to 10 mm from the same viewpoint, and preferably from 0.5 to 5 mm. When other metals such as nickel are used, the thickness of the electrode is preferably from 0.0001 to 5 mm, preferably from 0.03 to 1 mm, from the viewpoint of cost reduction because the degree of self-reaction is small. Further, a metal such as nickel can also be formed in the form of a plating layer.

The porous system is in contact with the anode and cathode and is interposed between the two poles. The porous body may be any object having a communicating hole, and examples thereof include a sponge (foam), a nonwoven fabric, a woven fabric, a paper, a porous film, a sintered body, and a porous plate.

The porosity of the porous body is preferably from 30 to 99.9%, preferably from 80 to 99.5%, from the viewpoint of ensuring a space for accommodating by-products while maintaining contact with the electrode. Further, the porosity (%) is a value calculated by (1-(density of porous body/density of material)) × 100.

The average pore diameter of the surface of the porous body is preferably from 1 to 3000 μm, preferably from 50 to 100 μm, from the viewpoint of suppressing the blocking of the pores while ensuring the contact state with the electrode. The average pore size is determined by microscopic observation of the surface, and the value obtained by the number average is obtained.

The material of the porous body may be any one of an insulating material such as a resin or a ceramic, or a substance which is electrically conductively enhanced by adding a conductive material. However, from the viewpoint of retaining the aqueous electrolyte solution, a hydrophilic material is preferred. In the case of a porous body made of a resin, a person who can be elastically deformed, a plastically deformable person, a person who hardly deforms, and the like are preferable, and a porous body composed of an elastically deformable sponge resin is particularly preferable.

Examples of the resin constituting the porous body include a melamine resin, a urethane resin, a phenol resin, a polypropylene resin, a polyethylene resin, a polyester resin, a polyamide resin, an epoxy resin, a cellulose resin, and the like. . Among them, a melamine resin, an urethane resin, a polyester resin, or a cellulose resin is preferable from the viewpoint that a porous body having an appropriate porosity, pore diameter, and elasticity can be easily obtained.

The thickness (operating state) of the porous body or the distance between the electrodes is preferably from 1 to 10 mm, preferably from 2 to 5 mm, from the viewpoint of maintaining the aqueous electrolyte solution and ensuring the space for accommodating by-products. The porous body may be a single layer or a plurality of layers, and in the case of a plurality of layers, the pore size of each layer may be changed, and the different types may be laminated. In the case of using an elastically deformable porous body, from the viewpoint of improving contact, it is preferably 1 to 3 times the distance from the disposed electrode, and 1.2 to 2 times is preferable. .

The porous body can hold the aqueous electrolyte solution. The aqueous electrolyte solution may be acidic or basic, and from the viewpoint of exhibiting acidity and alkalinity at the two poles, it is preferably neutral, for example, pH 5 to 9, and pH 6 to 8 is preferred.

The electrolyte contained in the aqueous electrolyte solution may be any of an alkali metal salt, an alkaline earth metal salt, another metal salt, an ammonium salt, a phosphonium salt, etc., and from the viewpoint of handling, sodium chloride, chlorination Potassium and lithium chloride are preferred. The electrolyte may be mixed in two or more kinds, or an acid salt or a basic salt may be used in combination. In addition, an alkaline substance or an acidic substance may be used in combination.

The concentration of the electrolyte is preferably from 5 to 30% by weight, and preferably from 20 to 26% by weight, from the viewpoint of adjusting the electric resistance to an appropriate degree and allowing the electrode reaction to proceed efficiently. Further, water may be additionally added in the middle of the hydrogen generation reaction, or an additional electrolyte may be added. In addition, an electrolyte or the like may be previously added (impregnated and dried) to the porous body, and water or the like may be supplied at the initial stage of the reaction to hold the porous body in the aqueous electrolyte solution. Alternatively, the reaction may be carried out in a state in which the electrolyte which does not completely dissolve (saturated state) is present.

The aqueous electrolyte solution may be present in the container as long as at least a part thereof is held in the porous body. Further, all of the aqueous electrolyte solution may be held in the porous body. Alternatively, an aqueous electrolyte solution may be additionally added in the middle of the hydrogen generation reaction.

The amount of the aqueous electrolyte solution is preferably from 1,500 to 10,000 parts by weight, based on 100 parts by weight of the total weight of the electrode, from 2000 to 5000 parts by weight, from the viewpoint that the hydrogen generation reaction is not excessively or insufficiently performed. Preferably.

In the present invention, hydrogen is generated by energizing the two electrodes or applying a voltage to the two electrodes. In the case where a potential difference is generated between the two poles, the electrode reaction can be continued only by energizing the two poles, and when no potential difference is generated between the two poles, it is necessary to apply a voltage to the two poles at least initially. Further, even when the electrodes are reacted only by energizing the two electrodes, the electrode can be activated at an early stage by applying a voltage at an initial stage. In the case where the two poles are energized, the resistance may be placed therein, or the current may be controlled by the variable resistor to control the hydrogen production.

In the case where a voltage is applied to the two poles, the voltage may be changed, or the switching control may be performed, or the energization and application may be repeated. In addition, the positive and negative voltages can be applied in the opposite way on the way, or an alternating voltage can be applied. However, in order to maintain the acidity and the alkalinity in the vicinity of each electrode, it is preferable to maintain the positive and negative reversal for at least one minute or more.

In the case where a voltage is applied to the aluminum-containing anode and the aluminum-containing cathode, in order to achieve a moderate self-reaction rate, it is preferable to apply 0.1 to 5 V, and it is preferable to apply 0.5 to 1.5 V. In the case where a voltage is applied to the magnesium-containing anode and the magnesium-containing cathode, in order to achieve a moderate self-reaction rate, it is preferable to apply 0.3 to 5 V, and it is preferable to apply 1 to 3 V. In the case where a voltage is applied to the magnesium-containing anode and the aluminum-containing cathode, in order to achieve a moderate self-reaction rate, it is preferable to apply 0 to 2 V, and it is preferable to apply 0 to 0.5 V.

The current during the application is determined according to the voltage value and the resistance of the system, and the resistance of the system varies depending on the electrode area, the electrolyte concentration, the distance between the electrodes, the number of electrodes, the porosity of the porous body, and the like. .

When a voltage is applied, in addition to being applied at a constant voltage, voltage control of a fixed current, voltage control of a fixed hydrogen production, or current control of a corresponding voltage or the like may be performed. In the present invention, the efficiency of hydrogen generation is high, and when the generated hydrogen is supplied to the fuel cell, if the generated electric power exceeds the consumed electric power of the electrolysis, that is, the electric power balance can be positive. Therefore, the application of the voltage can also be performed by supplying the generated hydrogen to the fuel cell.

The hydrogen generation method of the present invention can be suitably carried out using the hydrogen generator of the present invention. In the hydrogen generator of the present invention, any of the electrode, the porous body, the aqueous electrolyte solution, and the application conditions of the voltage described above can be used. Hereinafter, the specific arrangement of the electrode and the porous body in the hydrogen generating apparatus of the present invention will be described with reference to the drawings.

Figure 1 (a) illustrates the most basic configuration. That is, the hydrogen generator of the present invention, as shown in Fig. 1(a), is characterized in that it comprises: an anode containing magnesium or aluminum, a cathode 2 containing magnesium or aluminum, and being placed in contact with and holding the two poles. The porous body 3 of the aqueous electrolyte solution 4, means for energizing the two electrodes or applying a voltage to the two electrodes (the power source 5). In the case where the two poles are energized, a switch, a wiring, or the like can be used instead of the power source 5.

In Fig. 1(a), a case where a voltage is applied to the electrodes by the power source 5 is exemplified, and a plate-shaped anode 1 and a cathode 2 are disposed at both ends of the container, and the porous body 3 is placed in contact with the two electrodes. When the porous body 3 is elastically deformable, it is disposed between the two poles in a pre-compressed state, and the contact state is further improved by the elastic restoring force.

In the example of Fig. 1(b), the anode 1 and the cathode 2 are placed in a container in a state of being sandwiched by the porous bodies 3 on both sides. In this manner, by disposing the porous body 3 on both sides of the electrode, the amount of the aqueous electrolyte solution held therein can be increased, and the total amount of hydrogen generation can be increased.

In the example of Fig. 1(c), two cathodes 2 are provided for one anode 1, and a voltage is applied by the power source 5 in parallel. By using a plurality of electrodes in such a manner, since the number of places where the reaction proceeds can be increased, the total amount of hydrogen generation can be made larger. In the present invention, a plurality of electrodes may be further provided and each connected in series.

In the example of Fig. 2(a), the porous body 3 is disposed in a container having a substantially square cross section, and a plate-shaped anode 1 is disposed in two slits disposed in a direction parallel to the diagonal direction. With cathode 2. The two-pole system is in contact with the porous body 3, and when the porous body 3 is elastically deformable, it is placed in a container in a pre-compressed state, and the contact state is further improved by the elastic restoring force.

In the example of Fig. 2(b), one end of the porous body 3 having a longer electrode width is sandwiched between the plate-shaped anode 1 and the cathode 2, and the portion which is not clamped is wound around the anode 1 and The container 2 is housed in a container in a state around it. With this configuration, the porous body 3 is also present around the two poles, and the porous body 3 is continuously integrated with the porous body 3 interposed between the two electrodes. Similarly, the central portion of the porous body 3 having a longer electrode width may be sandwiched between the plate-shaped anode 1 and the cathode 2, and the portions which are not sandwiched on both sides are wound around the anode 1 and the cathode 2 It is housed in a container in a surrounding state.

In the example of Fig. 2(c), the plate-shaped anode 1 and the cathode 2 are processed into a substantially circular shape, and a porous body 3 having a thickness almost constant is provided between the two electrodes. Similarly, a plate-shaped anode 1 and a cathode 2, a porous body 3 sandwiched between the two electrodes, and a porous body 3 laminated on the inner side or the outer side thereof may be used, and the laminated body may be wound into a spiral shape.

In the hydrogen generating apparatus, a closed type or an open type container may be used, and a discharge path for discharging the generated hydrogen gas or a supply path or an adding means for introducing a material or an aqueous solution or the like for voltage application may be provided as necessary. Control devices used for control, etc. In addition, means for performing heat preservation or warming can be appropriately set.

Since the hydrogen generation method of the present invention can simplify the device structure of the hydrogen generator, it is particularly effective in the case of a hydrogen supply device for a fuel cell for carrying a device.

[Examples]

Hereinafter, embodiments and the like which specifically disclose the constitution and effects of the present invention will be described.

Example 1

Two aluminum plates (purity: 99.5%, vertical 35 × width 50 × thickness 0.3 mm, 1.44 g) were prepared, and a porous body (manufactured by BASF Corporation, melamine foam, longitudinal 35 × width 50 × thickness 5 mm, density: 0.0093) g/cm ³ , porosity 99.4%, average pore diameter 70 μm) were sandwiched between two, placed in a flat outer casing (about 8 mL) with a distance of 5 mm between the electrodes, and injected into a 20% by weight NaCl aqueous solution. 8mL. The upper space of the outer casing is a closed space, and a membrane flow meter (manufactured by Horiba, Ltd.) is connected to a flow path for discharging hydrogen gas, and the hydrogen generation flow rate is constantly monitored. Each electrode was connected to a stable power source as a positive electrode and a negative electrode, and the flow rate of hydrogen generation was about 10 mL/min, and the current value of the power source was manually changed while operating for one hour. The hydrogen production at this time is disclosed in Fig. 3(a), and the relationship between voltage and current is disclosed in Fig. 3(b), and the generated electric power and consumed electric power calculated by the above are disclosed in Fig. 3(c). Further, in the case where the hydrogen generation flow rate was 10 mL/min, the electric power generated by the fuel cell was set to 0.83 W and was calculated.

From this result, it is understood that power generation can be more than the power consumption (1.14 to 5.2 times). It can be inferred that by applying a voltage, aluminum of the electrode is activated, and hydrogen is generated by self-reaction other than electrolysis. In addition, the duration of power consumption of 0.5 W or less is about 90 minutes.

Example 2

Except that the porous body used in Example 1 was changed to the following porous body, the hydrogen generation flow rate was about 10 mL/min under the same conditions as in Example 1, and the power source was manually operated. The current value changes while running for 1 hour. The power consumption calculated from the voltage and current at this time and the result of Example 1 are disclosed in FIG.

(Example 2-1) SOFROUS (polyurethane, 0.22 g/cm ³ , porosity 82%, average pore diameter 1 μm) 5 mm thickness

(Example 2-2) Polyurethane (washing sponge, 0.028 g/cm ³ , porosity 98%, average pore diameter 2000 μm) 5 mm thickness

(Example 2-3) Evaporation paper (polyester resin, 0.26 g/cm ³ , porosity 78%, average pore diameter 50 μm) 1 mm thick × 5 pieces

(Example 2-4) BELLEATER (polyvinyl alcohol sponge, 0.089 g/cm ³ , porosity 95%, average pore diameter 70 μm) 1.8 mm thick × 2 pieces.

Comparative example 1

Except that the porous body was not used in Example 1, and only the same amount of NaCl aqueous solution was present between the electrodes, the hydrogen generation flow rate was about 10 mL/min under the same conditions as in Example 1 to manually The current value of the power supply changes and operates for one hour at the same time. The power consumption calculated from the voltage and current at this time is disclosed in FIG. As a result, when the porous body is not used, the initial power consumption is extremely large, and the power balance is negative (power consumption is 0.8 W or more).

Example 3-1

Two aluminum plates (purity: 99.5%, length: 35 × width: 20 × thickness: 0.3 mm, 0.57 g) were prepared, and one porous body (manufactured by BASF Corporation, melamine foam, and each of the two sides) was placed between the two. Vertical 35 × horizontal 50 × thickness 5 mm, density 0.0093 g / cm ³ , porosity 99.4%), placed in a container (depth 35 × length 50 × width 15mm, volume about 27mL), and injected into a 20% by weight NaCl aqueous solution 15mL. The upper space of the container was used as a sealed space, and a membrane flowmeter (manufactured by Horiba, Ltd.) was connected to a flow path for discharging hydrogen gas to perform measurement. Each electrode was connected to a stable power source as a positive electrode and a negative electrode, and the current value of the power source was controlled to 0.5 A for 2 hours. The power consumption at this time is disclosed in FIG. 5(a), the power consumption is disclosed in FIG. 5(b), the available power is disclosed in FIG. 5(c), and the usable power is disclosed in FIG. 5(d).

Example 3-2

The operation was carried out for 2 hours under the same conditions as in Example 3-1, except that the thickness of the porous body used in Example 3-1 was changed to 10 mm. The power consumption at this time is disclosed in FIG. 5(a), the power consumption is disclosed in FIG. 5(b), the available power is disclosed in FIG. 5(c), and the available power is disclosed in FIG. 5(d).

Comparative example 2

In addition to changing the thickness of the three porous bodies used in Example 3-1 to 3 mm, a frame-shaped spacer composed of a silicone rubber having a thickness of 1 mm (only the upper end and the lower end were 2 mm wide and the electrode phase) The operation was carried out for 2 hours under the same conditions as in Example 3-1 except that the distance between the electrode and the porous body was 1 mm between the porous body and the electrode. The power consumption at this time is disclosed in FIG. 5(a), the power consumption is disclosed in FIG. 5(b), the available power is disclosed in FIG. 5(c), and the available power is disclosed in FIG. 5(d).

Comparing the results of Examples 3-1 and 3-2 with Comparative Example 2, it is understood that the better the contact between the aluminum electrode and the sponge, the more the reaction efficiency is improved, especially in the case of non-contact, the reaction is passivated and consumed. Electricity surges.

Example 4-1

Two magnesium plates (AZ31, purity 96%, length 35×width 20×thickness 0.3 mm, 0.36 g) were prepared, and one porous body (manufactured by BASF Corporation, melamine) was placed between the two sides. Foam, longitudinal 35 × width 50 × thickness 5 mm, density 0.0093 g / cm ³ , porosity 99.4%), placed in a container (depth 35 × length 50 × width 15mm, volume about 27mL), and injected 20% by weight The aqueous NaCl solution was about 15 mL. The upper space of the container was used as a sealed space, and a membrane flowmeter (manufactured by Horiba, Ltd.) was connected to a flow path for discharging hydrogen gas to perform measurement. Each electrode was connected to a stable power source as a positive electrode and a negative electrode, and the current value of the power source was controlled to 0.5 A, and the operation was performed for 1 hour. The power consumption at this time is shown in Fig. 6(a), the power consumption is shown in Fig. 6(b), the available power is shown in Fig. 6(c), and the available power is shown in Fig. 6(d).

Example 4-2

The operation was carried out for 1 hour under the same conditions as in Example 4-1, except that the thickness of the porous body used in Example 4-1 was changed to 10 mm. The power consumption at this time is disclosed in FIG. 6(a), the power consumption is disclosed in FIG. 6(b), the available power is disclosed in FIG. 6(c), and the available power is disclosed in FIG. 6(d).

Comparative example 3

In addition to changing the thickness of the three porous bodies used in Example 4-1 to 3 mm, a frame-shaped spacer composed of a silicone rubber having a thickness of 1 mm (only the upper end and the lower end were 2 mm wide and the electrode phase) The operation was carried out for 1 hour under the same conditions as in Example 4-1 except that the distance between the electrode and the porous body was between 1 mm and the distance between the porous body and the electrode. The power consumption at this time is disclosed in FIG. 6(a), the power consumption is disclosed in FIG. 6(b), the available power is disclosed in FIG. 6(c), and the available power is disclosed in FIG. 6(d).

Comparing the results of Examples 4-1 and 4-2 with Comparative Example 3, it is understood that the reaction is passivated in the case of non-contact, and the power consumption is increased. The weaker the contact between the magnesium electrode and the sponge, the more the reaction efficiency is improved. It is presumed that the stronger the contact, the more difficult it is to allow the accumulation of magnesium by-products (oxides, hydroxides).

Example 5-1

Prepare a magnesium plate (purity of 96%, length of 35 × width of 20 × thickness of 0.3 mm, 0.36 g) as an anode and an aluminum plate (purity of 99.5%, length of 35 × width of 20 × thickness of 0.3 mm, 0.57 g) as a cathode, at 2 One porous body (manufactured by BASF Corporation, melamine foam, vertical 35×width 50×thickness 5 mm, density: 0.0093 g/cm ³ , porosity: 99.4%) was placed between the two sides, and placed in a container ( The depth was 35×length 50×width 15 mm, the volume was about 27 mL), and about 15 mL of a 20% by weight NaCl aqueous solution was injected. The upper space of the container was used as a sealed space, and a membrane flowmeter (manufactured by Horiba, Ltd.) was connected to a flow path for discharging hydrogen gas to perform measurement. Each of the electrodes was energized with a copper plate (width 10 mm, thickness 0.5 mm, resistance 5 to 8 mΩ), and the operation was performed until the hydrogen generation flow rate was about 6 mL/min or less. The available electric power at this time is disclosed in Fig. 7(a), and the usable electric power is disclosed in Fig. 7(b).

Example 5-2

The operation was carried out for 1 hour under the same conditions as in Example 5-1, except that the thickness of the porous body used in Example 5-1 was changed to 10 mm. The available power at this time is disclosed in Fig. 7(a), and the available power is disclosed in Fig. 7(b).

Comparative example 4

In addition to changing the thickness of the three porous bodies used in Example 5-1 to 3 mm, a frame-shaped spacer composed of a silicone rubber having a thickness of 1 mm (only the upper end and the lower end were 2 mm wide and the electrode phase) The operation was carried out for 1 hour under the same conditions as in Example 5-1 except that the distance between the electrode and the porous body was 1 mm between the porous body and the electrode. The available power at this time is disclosed in Fig. 7(a), and the usable power is disclosed in Fig. 7(b).

If the results of Examples 5-1 and 5-2 are compared with those of Comparative Example 4, the efficiency of the hydrogen generation reaction hardly changes, but in the case of non-contact, the reaction hindrance due to by-products occurs very early, so The amount of electricity used is getting smaller.

(comparison of self-response rate)

From the results of Examples 3-1, 4-1, and 5-1, the self-reaction rate was calculated in the following manner. That is, the amount of hydrogen generated in the electrolysis reaction is calculated from the "number of moving electrons" obtained by the current, and is subtracted from the actual hydrogen production, and the ratio of the self-reaction to the electrolysis reaction of each electrode is obtained.

Equation 1

If the current flowing in 1 second of 1 amp is set to Ne mol

When the hydrogen generation flow rate is S ml/min, the amount of hydrogen produced is NH.

Therefore, the amount of spontaneous reaction generated by the battery reaction does not contribute to the amount NS is

NS=NH-1/2Ne(mol)

The result is disclosed in Fig. 8(a). In addition, the data of the current value and the voltage value used for calculation are disclosed in FIG. 8(b) and FIG. 8(c), respectively. From the results of Fig. 8, it is understood that the ratio of the self-reaction increases in the order of Al-Mg, Al-Al, and Mg-Mg.

(pH measurement test)

As shown in Fig. 9 (a), two aluminum plates (purity: 99.5%, vertical 35 × width 50 × thickness 0.3 mm, 1.44 g) were prepared as electrodes, and were placed in a container so that the distance between the electrodes was 45 mm ( About 27 mL) was placed in the center of the container by a cellophane film (cellophane made by TOYO Co., Ltd., thickness: 10 μm), and about 26 mL of a 20% by weight NaCl aqueous solution was injected. Each electrode was connected to a stable power source as a positive electrode and a negative electrode, and operated at a constant current value (0.5 A) for 1 hour. At this time, the pH of the center position of the electrode on the anode side and the cell paper film, and the center of the electrode on the cathode side and the center of the cellophane film were measured by a pH meter. The result is disclosed in Fig. 9(b).

From this result, it is understood that the acidity increases as the reaction proceeds with the anode, and the alkalinity increases with the reaction at the cathode. In the same manner as described above, the pH in the vicinity of each electrode was measured in Example 3-1, and as a result, it was found that the acidity and alkalinity were further increased by the contact with the porous body.

Example 6-1

Two magnesium plates (purity: 96%, length: 57 × width, 10 × thickness, 0.3 mm, 0.3 g) were prepared as the anode, and three nickel plates as cathodes (purity of 99%, length of 57 × width of 10 × thickness of 0.05 mm, 0.26 g), when the interactive layer is contracted, one porous body (manufactured by BASF, melamine foam, length 57 × width 10 × thickness 5 mm, density 0.0093 g/cm ³ , porosity 99.4%) is placed in each layer. Four pieces were placed in a container (depth 57 × width 10 × width 5 mm, volume: about 2.85 mL), and about 3 mL of a 20% by weight NaCl aqueous solution was injected. The upper space of the container was used as a sealed space, and a membrane flowmeter (manufactured by Horiba, Ltd.) was connected to a flow path for discharging hydrogen gas to perform measurement. Each electrode was energized with a copper wire (resistance 8 mΩ) and operated for 20 minutes. The hydrogen production and flow rate at this time are disclosed in Figure 10.

Example 6-2

Except that the porous body used in Example 6-1 was changed to a sponge (manufactured by Well and Industrial Co., Ltd., FD sponge, material: polyvinyl acetate, length 57 × width 10 × thickness 5 mm, density 0.115) The operation was carried out under the same conditions as in Example 6-1 except that a g/cm ³ , a porosity of 88%) and a 10% by weight aqueous NaCl solution were used. One and the hydrogen production and flow rate at this time are shown in Figure 10.

Example 6-3

The porous body used in Example 6-1 was changed to a filter paper (manufactured by ADVANTEC Toyo Co., Ltd., trade name: 5B, length 57 × width 10 × thickness 0.21 mm × 3 laminates, density 0.514 g / The operation was carried out under the same conditions as in Example 6-1 except for cm ³ and a porosity of 46%. One and the hydrogen production and flow rate at this time are shown in Figure 10.

Example 7

The operation was carried out under the same conditions as in Example 6-1 except that the material of the cathode was changed to copper (purity 99%, length 57 × width 10 × thickness 0.05 mm, 0.16 g) in Example 6-1. . The hydrogen production and flow rate at this time were the same as those in Example 6-1.

1. . . anode

2. . . cathode

3. . . Porous body

4. . . Electrolyte aqueous solution

5. . . Power supply (method of applying voltage)

Fig. 1 is a longitudinal sectional view showing an example of a hydrogen generator of the present invention.

Fig. 2 is a cross-sectional view showing an example of a hydrogen generator of the present invention.

Fig. 3 is a graph showing the results of Example 1.

Fig. 4 is a graph showing the results of Examples 1 and 2 and Comparative Example 1.

Fig. 5 is a graph showing the results of Example 3 and Comparative Example 2.

Fig. 6 is a graph showing the results of Example 4 and Comparative Example 3.

Fig. 7 is a graph showing the results of Example 5 and Comparative Example 4.

Fig. 8 is a graph showing the results of Examples 3-1, 4-1, and 5-1.

Fig. 9 is a graph showing (a) a device used in the pH measurement test and (b) a measurement result.

Fig. 10 is a view showing the result of the embodiment 6.

1. . . anode

2. . . cathode

3. . . Porous body

4. . . Electrolyte aqueous solution

5. . . Power supply (method of applying voltage)

Claims (10)

A method for producing hydrogen, characterized in that a porous body is brought into contact with an anode and a cathode containing magnesium or aluminum and interposed between the two electrodes, and the porous body is maintained in an aqueous electrolyte solution to energize the two electrodes, or Hydrogen is generated by applying a voltage to the two electrodes; the porosity of the porous body is 30 to 99.9%, the thickness is 1 to 10 mm, and the average pore diameter is 1 to 100 μm. The method for producing hydrogen according to claim 1, wherein the cathode system contains magnesium or aluminum. The method for producing hydrogen according to claim 1, wherein the porous system is a porous body composed of an elastically deformable sponge resin. The method for producing hydrogen according to claim 1, wherein the anode and the cathode are formed in a plate shape, and the porous system is interposed between the two electrodes. The method for producing hydrogen according to claim 1, wherein a porous body is present around the two poles, and the porous system is continuously integrated with the porous body interposed between the two electrodes. A hydrogen generator comprising: an anode including a magnesium or aluminum, a cathode, a porous body disposed in contact with the two electrodes and holding the aqueous electrolyte solution, and means for applying a voltage to the two electrodes or applying a voltage to the two electrodes; The porosity of the porous body is 30 to 99.9%, the thickness is 1 to 10 mm, and the average pore diameter is 1 to 100 μm. The hydrogen generating device according to claim 6, wherein the cathode system contains magnesium or aluminum. The hydrogen generator according to claim 6, wherein the porous system is a porous body composed of an elastically deformable sponge resin. The hydrogen generating device according to claim 6, wherein the anode is The cathode is formed in a plate shape, and the porous system is interposed between the two electrodes. The hydrogen generator according to claim 6, wherein a porous body is present around the two poles, and the porous system is continuously integrated with the porous body interposed between the two electrodes.