JP2006218348A - Method of activating hydrogen adsorption material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of activating a hydrogen adsorption material by which the hydrogen adsorptivity of the hydrogen adsorption material housed in a hydrogen storage tank can be improved. <P>SOLUTION: A metal-organic frame structure (MOF) as the hydrogen adsorption material is housed in a vessel 10. Into the vessel 10, for example, polar molecules of methanol or the like are introduced. Thereby, the polar molecules and polar molecules of steam or the like adsorbed in the MOF mix to each other. Steam or the like separated, in other words, freed from an aggregation state by the interposition of the polar molecules between molecules of steam or the like can be easily discharged from the vessel by subsequent sucking and exhausting through a vacuum pump 18. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for activating a hydrogen adsorbent that improves the hydrogen gas adsorption capacity of a hydrogen adsorbent contained in a hydrogen gas storage tank.

  In recent years, a fuel cell vehicle equipped with a fuel cell has attracted attention due to a growing interest in environmental protection. This is because the fuel cell vehicle uses the fuel cell as a travel drive source, so there is no need to burn gasoline or light oil, and therefore no hydrocarbon gas, NOx, SOx, or the like is discharged.

  It is necessary to supply a fuel gas containing hydrogen and an oxidant gas containing oxygen to the fuel cell. As the oxidant gas, for example, air can be used. However, the fuel gas must be supplied from a fuel gas supply source such as a hydrogen gas storage tank. For this reason, the fuel cell vehicle is equipped with a fuel gas supply source in addition to the fuel cell.

  Thus, when a hydrogen gas storage tank is used as a fuel gas supply source, it has been studied that a hydrogen adsorbent is accommodated therein. In this case, since the hydrogen adsorbent adsorbs and holds hydrogen, more hydrogen can be stored as compared with the case where the hydrogen adsorbent is not accommodated.

  By the way, when a gas other than hydrogen gas, for example, water vapor or the like is adsorbed on the hydrogen adsorbing material, the hydrogen gas adsorbing amount of the hydrogen adsorbing material inevitably decreases. For this reason, a process for separating the gas other than the adsorbed hydrogen gas is required. As one type of such a processing method, for example, as described in Non-Patent Document 1, evacuation of carbon nanotubes at 350 ° C. for 3 hours can be mentioned.

  Patent Document 1 proposes that a gas adsorbent is adsorbed with a protective gas such as lower hydrocarbon, lower alcohol or inert gas, and then the gas adsorbent is accommodated in a container.

2001 NEDO result report “NEDO-WE-NET0011” for publication 51101633-3-1, Hydrogen Utilization International Clean Energy System Technology (WE-NET) Phase II R & D Task 11, “Development of Hydrogen Storage Materials” p355 -357 JP 2002-122296 A

  In the method described in Non-Patent Document 1, vacuum evacuation is performed at 350 ° C. for 3 hours after the carbon nanotube is filled in the container. In this case, since the container is heated, there is a concern that the container is deteriorated due to thermal strain or the like.

  Further, in the method described in Patent Document 1, since all of lower hydrocarbons, lower alcohols, and inert gases have a low boiling point, they are desorbed from the gas adsorbent during the storage of the gas adsorbent in the container. There is. In particular, in the case of an inert gas, this tendency is remarkable because its boiling point is well below room temperature as is well known.

  Furthermore, lower hydrocarbons and inert gases are nonpolar molecules, and their adsorption sites are different from polar molecules such as water vapor. Therefore, even if lower hydrocarbons and inert gas are used, there is an aspect that it is not easy to avoid the adsorption of water vapor, which is the main cause of the decrease in hydrogen gas adsorption capacity.

  The present invention has been made to solve the above-described problems, and provides a method for activating a hydrogen adsorbent capable of desorbing polar molecules such as water vapor without deteriorating the container. With the goal.

In order to achieve the above object, the present invention provides a hydrogen adsorbent for removing gas other than hydrogen gas adsorbed on the surface of the hydrogen adsorbent accommodated in the container before filling the container with hydrogen gas. An activation method comprising:
Storing a hydrogen adsorbent in a container;
Adsorbing polar molecules having a boiling point lower than that of water to the hydrogen adsorbent;
Desorbing the gas other than hydrogen gas and the polar molecule from the hydrogen adsorbent;
It is characterized by having.

  For example, a gas other than hydrogen gas such as water vapor is adsorbed to a hydrogen adsorbent exposed to the atmosphere when stored in a container. Water vapor or the like is a polar molecule. Therefore, in the present invention, polar molecules having a boiling point lower than that of water are introduced into the container and adsorbed on the hydrogen adsorbent. That is, the polar molecules are allowed to penetrate into the aggregated water vapor (water), whereby the polar molecules such as water vapor are separated from each other and the aggregation state disappears. The water vapor and the like separated from each other in this way can be easily discharged by suction exhaust. At this time, polar molecules having a boiling point lower than that of water are also easily discharged.

  Since water vapor and the like are removed in this manner, the number of sites capable of adsorbing hydrogen gas in the hydrogen adsorbent increases, and thus the hydrogen gas adsorption capacity is improved. In other words, the hydrogen adsorbent is activated.

  In the present invention, since the container is not subjected to heat treatment, thermal distortion does not occur in the container.

  Moreover, for example, since the hydrogen adsorbent in the container can be activated before being mounted on the fuel cell vehicle, it is not necessary to mount an activation system on the fuel cell vehicle. Therefore, the weight of the fuel cell vehicle is not increased, and the degree of freedom in device arrangement is not reduced.

  The polar molecule may be supplied as a liquid. Alternatively, polar molecules may be introduced into the container accompanied with an inert gas. In this case, for example, a liquid of polar molecules may be bubbled with an inert gas. Here, “inert gas” in the present invention refers to a gas that is not adsorbed by the hydrogen adsorbent.

  In order to desorb polar molecules from the hydrogen adsorbent, for example, suction exhaust may be performed. Alternatively, in place of suction exhaust, an inert gas may be circulated in the container.

  The polar molecule is not particularly limited as long as it is a substance having a boiling point lower than that of water, but those having a boiling point of 80 ° C. or less are suitable.

  In any case, a preferred example of the hydrogen adsorbent includes a metal-organic skeleton structure.

  According to the present invention, polar molecules such as water vapor adsorbed by the hydrogen adsorbent accommodated in the container are removed by introducing the polar molecules into the container. For this reason, water vapor | steam etc. are removed efficiently and, as a result, a hydrogen adsorbent is activated.

  In the present invention, since heat treatment is not performed on the container, thermal distortion does not occur in the container. In addition, since the hydrogen adsorbent in the container can be activated before actual use such as mounting the container on a fuel cell vehicle, there is no need to provide an activation system.

  Moreover, in the present invention, the hydrogen gas adsorbing ability of the hydrogen adsorbent can be easily improved by performing a very simple operation of introducing polar molecules into the container and then discharging the polar molecules.

  Hereinafter, preferred embodiments of the method for activating the hydrogen adsorbent according to the present invention will be described in detail with reference to the accompanying drawings. In the present embodiment, a metal-organic skeleton structure which is a kind of complex will be described as an example of the hydrogen adsorbent.

  The metal-organic framework structure is a structure in which metal atoms or metal ions are coordinated and bound so that the organic molecules or organic ions surround them, and maintains a stable porous framework structure even in the absence of guest molecules. To do. Note that hydrogen gas is adsorbed in the porous skeleton structure.

Specific examples of the metal-organic skeleton structure include [M ₂ (4,4′-bipyridine) ₃ (NO ₃ ) ₄ ] (where M is any one of Co, Ni, and Zn), [M ₂ (1 , 4-benzenedicarboxylate anion) ₂ ] (wherein M is either Cu or Zn), [Fe ₂ (trans-4,4′-azopyridine) ₄ (NCS) ₄ ] and the like.

As another specific example of the metal-organic framework, as described in US Patent Application Publication No. 2003/0004364, the general formula is represented by M ₄ O (aromatic dicarboxylate anion) ₃ . What is done. Suitable examples of M include Zn, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Al, Ru, Rh, Pd, Ag, and Pt. Moreover, it may be composed of an aromatic dicarboxylate anion derivative instead of the aromatic dicarboxylate anion.

  Preferable examples of the aromatic dicarboxylate anion or a derivative thereof include 1,4-benzenedicarboxylate anion, 2-bromo-1,4-benzenedicarboxylate anion, 2-amino-1,4-benzenedi Carboxylate anion, 2,5-propyl-1,4-benzenedicarboxylate anion, 2,5-pentyl-1,4-benzenedicarboxylate anion, cyclobutene-1,4-benzenedicarboxylate anion, 1, 4-naphthalenedicarboxylate anion, 2,6-naphthalenedicarboxylate anion, 4,4′-biphenyldicarboxylate anion, 4,5,9,10-tetrahydropyrene-2,7-dicarboxylate anion, pyrene -2,7-dicarboxylate anion, 4, "-. Terphenyl dicarboxylate anion, etc. Each structural formula is as follows.

  Hereinafter, the activation method according to the first embodiment will be described.

First, the metal-organic framework structure MOF as a hydrogen adsorbent is accommodated in the container 10 shown in FIG. In this case, the container 10 is made of SUS304, which is a kind of stainless steel, and has a pressure resistance of 20 MPa and a volume of 100 cm ³ . A cylindrical protrusion 12 is provided on the upper end surface of the container 10, and a filter 14 is held on the cylindrical protrusion 12. The metal-organic skeleton structure MOF may be unused, or may be one in which hydrogen gas adsorption ability is reduced by repeated adsorption and release of hydrogen gas.

  Next, a liquid having polar molecules is introduced into the container 10 through the cylindrical protrusion 12.

  Here, the liquid is selected to have a boiling point lower than that of water, preferably a boiling point (under 1 atm) of 80 ° C. or less. Specific examples of such polar molecules include the substances shown in Table 1 below. When the boiling point is higher than that of water, it is difficult to desorb from the metal-organic skeleton structure MOF.

  The polar molecules are introduced into the container 10 in an amount necessary to coat the entire surface of the metal-organic framework structure MOF with the polar molecules. This amount is determined from an adsorption isotherm when polar molecules are adsorbed on the metal-organic framework structure MOF. That is, as shown in FIG. 2, a linear region appears on the adsorption isotherm. The starting portion of this straight line region is designated as point B by Emmet and Browner, and this point B indicates that a single layer of polar molecules has been formed on the entire surface of the metal-organic framework structure MOF. Therefore, if the Y-axis coordinate at point B is read, the amount of polar molecules adsorbed, in other words, the amount of polar molecules introduced can be determined.

  Then, as shown in FIG. 3, a pipe 16 is connected to the cylindrical protrusion 12. A valve 20, a connector 22, and a valve 24 are interposed in the pipe 16 from the container 10 to the vacuum pump 18, and a pressure gauge 26 is disposed in the vicinity of the connector 22.

  While the valve 20 is opened, the valve 24 is closed, so that polar molecules are sealed in the container 10. Polar molecules (liquid) evaporate over time, and the pressure gauge 26 indication increases accordingly. When the time further elapses, the vaporized polar molecule is adsorbed on the metal-organic framework structure MOF, and the indication of the pressure gauge 26 is lowered.

  At this time, since the water vapor previously adsorbed on the metal-organic framework structure MOF is a polar molecule, the polar molecule is easily mixed with the water vapor. Eventually, polar molecules are interposed between water vapor (water molecules), and for this reason, water molecules are separated from each other.

  Thereafter, if the vacuum pump 18 is energized and the valve 24 is opened, the inside of the container 10 is sucked and exhausted under the action of the vacuum pump 18. At this time, polar molecules and water vapor are sucked and exhausted, so that the number of adsorption sites of the metal-organic framework structure MOF increases. That is, it is possible to improve the hydrogen gas adsorption ability of the metal-organic framework structure MOF, in other words, to activate the metal-organic framework structure MOF.

  As described above, according to the first embodiment, the aggregated state of water vapor is eliminated. Thereby, water vapor can be efficiently removed from the metal-organic framework structure MOF, and activation can be performed in a short time.

  In the first embodiment, activation can be performed without heating the container 10. Therefore, thermal distortion does not occur in the container 10.

The end of the activation process is determined by the degree of vacuum. That is, the valves 20 and 24 may be closed and the vacuum pump 18 may be stopped when the pressure gauge 26 indicates a predetermined pressure, for example, 10 ⁻³ Torr.

  After the activation process is completed, the pipe 16 is disconnected from the downstream side of the connector 22. Thereafter, the container 10 may be connected to a hydrogen gas supply system and charged with hydrogen gas.

  Next, a second embodiment will be described.

  FIG. 4 is a schematic configuration diagram of a suction / exhaust system 34 schematically showing a state in which a vacuum pump 32 for sucking and exhausting the inside of a container 30 in which a metal-organic framework structure MOF as a hydrogen adsorbent is accommodated is connected. It is.

  In this case, a first cylindrical protruding portion 36 and a second cylindrical protruding portion 38 are respectively provided on the lower end surface and the upper end surface of the container 30, and the first cylindrical protruding portion 36 and the second cylindrical protruding portion are provided. Valves 40 and 42 and connectors 44 and 46 are connected to each portion 38. Filters 48 and 50 are held in the respective openings reaching the first cylindrical protrusion 36 or the second cylindrical protrusion 38.

  The vacuum pump 32 is connected to an exhaust line 52 connected via a connector 44, while a pressure gauge 54 is connected to the connector 46 via a pipe 53.

  After housing the metal-organic framework MOF in the container 30, the vacuum pump 32 is energized and the valves 40 and 42 are opened. Thereby, the inside of the container 30 is sucked and exhausted. By this suction exhaust, replacement in the container 10 with the inert gas described later is completed in a short time, and the polar molecule adsorption process is also completed in a short time.

When the pressure gauge 54 indicates 10 ⁻¹ Torr, the valves 40 and 42 are closed. Then, the exhaust line 52 and the pipe 53 are disconnected from the downstream side of the connectors 44 and 46.

  Thereafter, as shown in FIG. 5, an activation processing system 60 is constructed. The activation processing system 60 has a supply line 62 connected to the connector 44 and an exhaust line 64 connected to the connector 46.

  In the supply line 62, a purifier 68, a valve 70, a bubbling device 72, and a valve 74 are disposed between the inert gas cylinder 66 and the connector 44. Further, a branch line 76 that is bridged between the upstream side of the valve 70 and the downstream side of the valve 74 is provided, and a valve 78, a heater 80, and a valve 82 are interposed in the branch line 76. The bubbling device 72 stores liquids (polar molecules) as shown in Table 1 above.

  On the other hand, a thermal conductivity detector 84 is disposed in the exhaust line 64, and a sampling pipe 86 branched from the downstream side of the valve 74 is connected to the thermal conductivity detector 84.

  While the valves 78 and 82 are closed, the valves 40, 42, 70 and 74 are opened, and the inert gas is introduced into the container 30 from the inert gas cylinder 66.

Here, the inert gas in the second embodiment refers to a gas that is not adsorbed by the metal-organic skeleton structure MOF that is a hydrogen adsorbent. Preferable examples of such a gas include N ₂ , Ar, Ne, He, Xe, Kr and the like.

The inert gas is first introduced into the purifier 68. For example, a column filled with molecular sieve is accommodated in the purifier 68, and H ₂ O, CO ₂ , CO, and O ₂ are removed from the inert gas that has passed through the column.

  The purified inert gas reaches the bubbling device 72 and bubbles the liquid (polar molecule). Thereby, the inert gas derived | led-out from the bubbling apparatus 72 distribute | circulates downstream in the state which accompanied the polar molecule.

  The inert gas is divided into a supply line 62 and a sampling pipe 86, and the portion that flows through the supply line 62 is introduced into the container 30, and then the polarity accompanied by the inert gas as in the first embodiment. Molecules and water vapor previously adsorbed on the metal-organic framework structure MOF are mixed together, and as a result, the water vapor aggregation state disappears in the same manner as described above.

  The thermal conductivity of the inert gas introduced into the sampling pipe 86 is compared with the thermal conductivity with the exhaust gas that has passed through the container 30 and reached the exhaust line 64 under the action of the thermal conductivity detector 84. The By examining the difference in thermal conductivity, the difference between the components of the gas introduced into the container 30 and the gas discharged from the container 30 can be understood. Since the integrated value of this difference means the total amount of polar molecules adsorbed on the metal-organic framework structure MOF (hydrogen adsorbent), by monitoring the integrated value, an amount corresponding to the point B in FIG. It can be determined that the polar molecule is adsorbed on the metal-organic framework MOF.

  Next, polar molecules are desorbed from the metal-organic framework structure MOF. In this case, the valves 70 and 74 are closed in advance and the valves 78 and 82 are opened. Thereby, the inert gas supplied from the inert gas cylinder 66 is heated to about 100 to 130 ° C. by the heater 80 and then introduced into the container 30. The gas adsorbed on the metal-organic framework structure MOF is absorbed by the introduced inert gas, and thereby desorbs from the metal-organic framework structure MOF. Further, since the inert gas is heated, the gas adsorbed on the metal-organic skeleton structure MOF is also activated by the transfer of thermal energy from the inert gas. Therefore, the gas can be separated from the metal-organic framework structure MOF more efficiently.

  During this flow, the heat of the inert gas introduced into the container 30 by the thermal conductivity detector 84 and the exhaust gas discharged from the container 30 accompanied by the gas released from the metal-organic framework structure MOF. A difference in conductivity is detected. When the difference in thermal conductivity becomes equal, it is determined that there is no difference between the components of the gas introduced into the container 30 and the gas discharged from the container 30, and the metal-organic framework structure MOF It is determined that the release of the gas, that is, the activation of the metal-organic framework MOF has been completed.

  By circulating the inert gas in the container 30 in this manner, polar molecules adsorbed on the metal-organic framework structure MOF (hydrogen adsorbent) can be efficiently removed.

  When the activation of the metal-organic framework MOF is completed, the valves 40 and 42 are closed, and the supply line 62 and the exhaust line 64 are disconnected from the downstream side of the connectors 44 and 46. Thereafter, the container 30 may be connected to a hydrogen gas supply system and filled with hydrogen gas.

  In the second embodiment, since the inert gas itself is heated, the heated inert gas is introduced into the container 30. Accordingly, since the heated inert gas uniformly contacts the metal-organic framework structure MOF accommodated in the container 30, a portion where polar molecules are not removed is generated in the metal-organic framework structure MOF. It is avoided. Further, thermal distortion does not occur in the container 30.

  In the second embodiment, the invasion of polar molecules between water vapor molecules (disappearance of the aggregation state of water molecules) and the desorption of water vapor and polar molecules are completed in a shorter time than in the first embodiment. In other words, there is an advantage that the activation process is efficiently performed.

  Moreover, according to the first and second embodiments described above, the metal-organic framework structure MOF in the containers 10 and 30 can be activated before the containers 10 and 30 are mounted on the fuel cell vehicle. Therefore, it is not necessary to attach an activation system for activation to the fuel cell vehicle. For this reason, the weight of the fuel cell vehicle is not increased, and the degree of freedom in device arrangement is not reduced.

  In the above-described embodiment, the metal-organic skeleton structure MOF has been described as an example of the hydrogen adsorbent, but it goes without saying that the hydrogen adsorbent is not particularly limited to this.

  In the second embodiment, it is not particularly necessary to heat the inert gas before introducing the inert gas into the container 30. Therefore, it is not particularly necessary to provide the heater 80 in the supply line 62.

Further, in order to purify the inert gas, a column other than a column packed with molecular sieves may be used. For example, when H ₂ O is removed from the inert gas, silica gel or diphosphorus pentoxide (P ₂ O _{5) is used.} ) May be used.

  Furthermore, although the case where water vapor was removed from the metal-organic framework structure MOF has been described as an example, the removal target is not limited to water vapor, and any polar molecule may be used.

1.2 g 2,6-naphthalenedicarboxylic acid and 11 g Zn (NO ₃ ) ₂ .4H ₂ O were dissolved in 1000 ml diethylformamide (DEF) in a closed vessel.

This solution was stored in a sealed container and heated at 95 ° C. for 20 hours while keeping the sealed container sealed, and Zn ₄ O (2,6-naphthalene) in which DEF molecules were physically adsorbed on the porous skeleton structure. Carboxylate anion) ₃ · (DEF) ₆ was obtained. The reaction product was filtered to separate it from the solvent DEF, and the filter residue Zn ₄ O (2,6-naphthalenedicarboxylate anion) _3. (DEF) ₆ was immersed in chloroform at room temperature for 24 hours. The DEF molecules physically adsorbed on the porous skeleton structure were replaced with CHCl ₃ molecules. This was separated from the solvent by filtration or the like, and then left standing in a vacuum evacuator and evacuated to desorb CHCl ₃ molecules from the porous skeleton structure, and Zn ₄ O (2,6-naphthalene). Carboxylate anion) ₃ .

This operation was repeated to obtain 210 g of powdery Zn ₄ O (2,6-naphthalenedicarboxylate anion) ₃ .

Next, when the methanol adsorption isotherm on Zn ₄ O (2,6-naphthalenedicarboxylate anion) ₃ was measured, the methanol adsorption amount at point B in FIG. 2 was 1 g of Zn ₄ O (2,6- It was found to be 0.28 g based on naphthalene dicarboxylate anion) ₃ .

Under atmospheric pressure at a temperature of 20 ° C., 50 g of Zn ₄ O (2,6-naphthalenedicarboxylate anion) ₃ is accommodated in the container 10, and 14 g of dehydrated methanol having a water content of 0.005 wt% or less. Was injected into the container 10. The amount of this dehydrated methanol corresponds to the amount of methanol adsorbed at point B with respect to 50 g of Zn ₄ O (2,6-naphthalenedicarboxylate anion) ₃ .

  Next, the container 10 was attached to the hydrogen gas adsorption amount measuring system 90 shown in FIG.

  Here, in this hydrogen gas adsorption amount measurement system 90, a supply line 92 for supplying hydrogen gas to the container 10 and a discharge line 94 for releasing hydrogen gas from the container 10 are branched from the connector 22. Provided.

  The supply line 92 is bridged from the hydrogen gas cylinder 96 to the container 10. A regulator 98 and a manual valve 100 are interposed in the supply line 92 from the hydrogen gas cylinder 96 side.

  On the other hand, a vacuum pump 102 is interposed in the discharge line 94, and until reaching the vacuum pump 102, a manual valve 104, a regulator 106, a needle valve 108, a mass flow meter 110, and an automatic valve 112 are arranged from the container 10 side. In FIG. 6, reference numerals 114 and 116 both indicate pressure gauges.

The container 10 was attached with the manual valves 100 and 104 of the hydrogen gas adsorption amount measurement system 90 both closed. Thereafter, when the valve 20 was opened, the pressure in the container 10 indicated by the pressure gauge 116 increased from the atmospheric pressure over time, decreased thereafter, and became atmospheric pressure after 30 minutes. That is, the total amount of methanol was adsorbed on Zn ₄ O (2,6-naphthalenedicarboxylate anion) ₃ .

Next, the gas in the supply line 92 and the discharge line 94 is removed, and gases other than methanol and hydrogen gas adsorbed on Zn ₄ O (2,6-naphthalenedicarboxylate anion) ₃ are separated and discharged. Therefore, the vacuum pump 102 was energized, the manual valves 100 and 104 were both opened, and the automatic valve 112 was further opened, and the evacuation was continued until the pressure reached 10 ⁻³ Torr. Thereafter, the manual valves 100 and 104 and the automatic valve 112 were closed, and the vacuum pump 102 was stopped.

  Next, the regulator 98 was set to 10 MPa, the manual valve 100 was opened, and 10 MPa hydrogen gas was introduced into the container 10.

  Thereafter, the manual valve 100 was closed, the vacuum pump 102 was energized, and the automatic valve 112 was opened. Further, the manual valve 104 was opened, and the hydrogen gas in the container 10 was released under the action of the vacuum pump 102.

  The released hydrogen gas is reduced in pressure to 0.1 MPa by the regulator 106 and the needle valve 108 and reaches the mass flow meter 110. The integrated flow rate of the hydrogen gas that has passed through the mass flow meter 110 is obtained, and when the increase in the integrated flow rate is no longer recognized, it is determined that all the hydrogen gas has been released, and the manual valve 104 and the automatic valve 112 are closed to make a vacuum. The pump 102 was stopped.

  The number of moles of released hydrogen gas determined as described above was 0.70 mol.

For comparison, hydrogen released from Zn ₄ O (2,6-naphthalenedicarboxylate anion) _{3 in} the same manner as described above except that methanol was not introduced into the vessel 10 and methanol was not removed. When the amount of gas was measured, the number of moles of released hydrogen gas was 0.66 mol. From this result, it is clear that by introducing methanol (polar molecule) into the container after the metal-organic framework structure MOF is accommodated in the container, a hydrogen adsorbing material having excellent hydrogen gas adsorption ability is obtained. .

After 50 g of Zn ₄ O (2,6-naphthalenedicarboxylate anion) ₃ was accommodated in the container 10, a hydrogen gas adsorption amount measurement system 90 shown in FIG. 6 was constructed. After activation by introduction of methanol and removal treatment of methanol according to Example 1, the above-described hydrogen gas adsorption / release operation was repeated 500 times.

  Thereafter, the container 10 was disconnected from the hydrogen gas adsorption amount measurement system 90, methanol was introduced again, and then the above methanol removal treatment was performed. Then, when the container 10 was incorporated again in the hydrogen gas adsorption amount measurement system 90 shown in FIG. 6 and the hydrogen gas adsorption / release operation was performed, the number of moles of the released hydrogen gas was 0.70 mol.

For comparison, the hydrogen gas adsorption / release operation was repeated 500 times without activating Zn ₄ O (2,6-naphthalenedicarboxylate anion) ₃ with methanol, and hydrogen without reactivation as described above. Gas adsorption / release operation was performed. At this time, the number of moles of released hydrogen gas was 0.61 mol. That is, it was confirmed that the number of moles of released hydrogen gas decreased by repeating the adsorption / release operation of hydrogen gas.

In addition, from this result, even Zn ₄ O (2,6-naphthalenedicarboxylate anion) ₃ that has repeatedly performed adsorption and release of hydrogen gas can be reactivated by introducing methanol. it is obvious.

It is a schematic whole longitudinal cross-sectional view of the container for enforcing the activation method which concerns on 1st Embodiment. It is a graph which shows the adsorption isotherm for setting the introduction amount of a polar molecule. It is a schematic block diagram of the suction exhaust system for sucking and exhausting the polar molecule introduced into the container. It is a schematic block diagram of the suction exhaust system for suction-exhausting the inside of a container before performing an activation process. It is a schematic block diagram of the activation system for activating a hydrogen adsorbent. It is a system schematic block diagram which shows the hydrogen gas adsorption amount measuring system for measuring the hydrogen gas discharge | release amount of a hydrogen adsorbent.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 30 ... Container 18, 32, 102 ... Vacuum pump 34 ... Suction exhaust system 68 ... Purifier 72 ... Bubbling device 80 ... Heater 84 ... Thermal conductivity detector 90 ... Hydrogen gas adsorption amount measuring system 92 ... Supply line 94 ... Discharge line 96 ... Hydrogen gas cylinder 110 ... Mass flow meter MOF ... Metal-organic framework

Claims (6)

A method of activating a hydrogen adsorbent that removes gas other than hydrogen gas adsorbed on the surface of the hydrogen adsorbent contained in the container before filling the container with hydrogen gas,
Storing a hydrogen adsorbent in a container;
Adsorbing polar molecules having a boiling point lower than that of water to the hydrogen adsorbent;
Desorbing the gas other than hydrogen gas and the polar molecule from the hydrogen adsorbent;
A method for activating a hydrogen adsorbent characterized by comprising:   The activation method according to claim 1, wherein the polar molecule is supplied as a liquid.   2. The activation method according to claim 1, wherein the polar molecule is introduced into the container together with an inert gas.   The activation method according to claim 1, wherein the gas other than hydrogen gas and the polar molecule are desorbed from the hydrogen adsorbent by performing suction and exhaust. Material activation method.   The activation method according to any one of claims 1 to 3, wherein the gas other than hydrogen gas and the polar molecule are desorbed from the hydrogen adsorbent by flowing an inert gas into the container. A method for activating a hydrogen adsorbent characterized.   6. The activation method according to claim 1, wherein the polar molecule has a boiling point of 80 [deg.] C. or less.

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