TW200925162A - Fast synthesis and storage method for hydrogen storage material of metal-organic framework with high specific surface area - Google Patents

Abstract

A fast synthesis and storage method for metal-organic framework (MOF) material with high specific surface area, which is performed by changing the influence interrelationship of parameter factors such as molar ratio of precursors, solvent contents, reaction time, and reaction temperatures with respect to the specific surface area (SSA), finding out the important operation variables, and finding out the condition of synthesizing the metal-organic framework-5 (MOF-5) material with the highest specific surface area in the shortest time by changing the important operation variables. The method can reduce the reaction time to twelve hours under the condition of high reaction temperature 120 Degrees Celcius so as to rapidly synthesize the metal-organic framework material with the high specific surface area, wherein the specific surface area (SSA) is greater than 3000m.sup.2/g so as to improve the yield. Since the metal-organic framework material has a property of tending to absorb water even under low humidity, vacuum storage period and resulting in phase structure decomposition, resulting in rapid reduction of specific surface area and hydrogen storage capability and reduction of storage life. This work provides a storage treatment method, and the structural stability can be elevated and the storage life can be prolonged as well after treated by the storage treatment method.

Description

200925162 * IX. Description of the Invention: [Technical Field] The present invention relates to a method for rapidly synthesizing and preserving a microporous material of a metal-organic framework having a high specific surface area, which has a relatively high hydrogen absorption capacity due to high specific surface area characteristics. The ratio is improved, so the material has high hydrogen storage capacity. In recent years, it has been confirmed in the literature that the argon storage capacity of this material can reach 4.5~5.1wt% under 77K and the hydrogen storage capacity can reach 0.4wt% at normal temperature 298K. The hydrogen storage capacity can be applied to hydrogen energy storage applications such as fuel cells or portable vehicles in the future, and is a potential energy material. In addition, metal-organic framework materials, which have extremely high surface area and porous materials, play an important role in catalytic reactions, gas separation and gas storage applications. In this work, a rapid synthesis and preservation method of microporous materials with metal-organic framework was proposed. The synthesis conditions of the samples were shortened at a high reaction temperature of 120 ° C for 12 hours to synthesize a metal with a specific surface area higher than 3000 m 2 /g. The organic framework material and the sample are activated to increase the structural stability of the material and extend the storage period. [Prior Art] The metal organic skeleton is a newly developed microporous material in recent years, which is more commonly used in conventional hydrogen storage materials such as metal hydride, zeolite (zeolites) and carbon nanotubes ( Materials such as nano-carbon tube are more in line with US Energy 5 200925162. • The conditions and standards for the development of commercially available hydrogen storage materials in the source (臓) hydrogen program, such as: (1) light weight (2) can be reused (3) Its hydrogen storage weight density is high (4) It can release hydrogen at normal temperature and appropriate pressure (5) The reaction rate of hydrogen absorption and desorption is fast (6) The synthesis method is simple and the cost is low. Metal-organic framework materials (also known as metal-organic coordination polymers), which are self-assembled by metal ions (metaj clusters) and organic molecular linkers to form an open 3D network (open 3D network) The crystal structure allows hydrogen to be efficiently adsorbed inside the molecular micropores by physical adsorption. The ideal metal organic framework material has an ordered structure, and the formation of an open microporous pore structure (micr〇p〇r〇us structure) results in a high specific surface area and a microporous volume. For example, the typical M〇F_5 自我 self-assembles by metal ions (Zn2+) and organic ligands (terephthalic acid, BDC) to form porous ordered crystals with an average pore radius of 8A. The metal organic framework material can arbitrarily change the metal ion species and the length of the organic linker, thereby adjusting the size, specific surface area and hydrogen storage capacity of the material to form another series of MOF forms. However, the MOF-5 material is the most mature development technology. It has a high specific surface area and high thermal stability and was selected as a representative material for the general study of metal organic frameworks. 200925162 In 1999, the synthesis of organometallic framework materials was first proposed by the Yaghi team (Li, Η·; Eddaoudi, M.; O^eeffe, Μ.; Yaghi, Ο. Μ. Nature, 402, 276 (1999)). Zinc nitrate (Ζn(Ν03)2·4Η20) and a pair of benzoenedicarboxylate (H2BDC), dissolved in dimethylformamide (DMF) and monochlorobenzene (Chlorobenzene), and further adding a triethanolamine (TEA) and an argon peroxide (Hydrogen 0 Peroxide, H2〇2) reagent, the synthesis time is 7-10 days at room temperature, thereby obtaining Langmuir has a specific surface area of 2,900 square meters per gram (m2/g); in 2005, Yaghi et al. (Andrew R. Millward and Ο. Μ. Yaghi, J. Am. Chem. Soc., 121^17998 ( 2005)) The zinc nitrate and the terephthalic acid are further dissolved in a solvent of N, N-Diethylformamide (DEF) to increase the reaction temperature to 100 ° C and shorten The reaction time was 20 hours, and a crystal having a microporous structure (Zn40(BDC)3) was synthesized, and its specific surface area was 2833 m2/g. In addition, Hirscher et al. (Panella, B.; Hirscher, M., di/v. 17, 538 (2005)) dissolved 1.2 g of zinc nitrate and 0.334 g of terephthalic acid in 40 ml (mL). In dimethyl decylamine, the solution is vigorously stirred under an atmosphere, and 2.2 ml of triethanolamine is slowly added to the solution while stirring, after the reaction time is about 30 to 45 minutes. A white solid crystal having a specific surface area of 1014 m 2 /g can be produced. Most of the above-mentioned team synthesis temperatures are 7 200925162 R.T~100 °C, and the reaction time is 20 hours to 10 days. The reaction time is lowered by increasing the temperature to synthesize a metal organic skeleton material with a high specific surface area. On the other hand, Huang et al. (Huang, L.; Wang, H.; Chen, J.; Wang, Z.; Sun, J.; Zhao, D.; Yan, Y. Microporous MeiOporows Maier., 58, 105 (2003) )) proposes a large and rapid synthesis strategy approach, which is also widely accepted as another synthetic strategy. When DMF is used as a solvent and stirred vigorously at room temperature for 0.5-4 Torr, a MOF-5 material having a specific surface area of 700 to 1300 m2/g can be synthesized. However, it is published according to the latest literature (Hafizovic, J.; Bj (j>rgen, M.; Olsbye, U.; Dietzel, PD C.; Bordiga, S.; Prestipino, C.; Lamberti, C.; Lillerud, KPJ Am. <5%., 129, 3612 (2007)) pointed out that it uses X-ray diffraction analyzer to find out that Huang scholars obtained a large number of rapid synthesis methods as imperfect metal-organic framework materials, so that there is The lower specific surface area, while the literature proposes the latest metal-organic framework crystal quality® (related to the specific surface area value) is quickly identified as Powder X-ray diffraction (PXRD). In many published journals or papers, it is known that the metal-organic framework materials are reacted at RT~100 °C, and the reaction conditions still need to be between 20 hours and 10 days to synthesize more than 3000 m2/g. The surface area of the metal-organic framework material generally increases the reaction temperature to lower the reaction time, but the current reaction temperature is still at 100 200925162. Other materials obtained by other scholars using the low-temperature rapid synthesis method have a specific surface area of up to ~12〇〇m2/ g It is impossible to obtain good quality. If the metal organic framework material with a specific surface area higher than 3000 m2/g is synthesized according to the above method, the reaction temperature is at the loot, and the preparation time is as short as 20 hours, which not only takes a long time to reduce the process time. The yield, and relative to the cost of the process, can not be achieved, so the average user can not meet the needs of the user in actual use. 〇 According to the team (Li H.; Eddaoudi, M. Groy, TL;

Yaghl' 〇·Μ” J·Mei 120, 8571 (1998)) In the 19=year literature, it is pointed out that the metal-organic framework material has the property of being easily absorbed by water and causing phase structure decomposition even under the preservation of low-fishing d. The material is easy to be damaged and the storage period is short. This work proposes a 2 preservation processing method 'processed by the preservation method' to increase the structural stability and extend the storage period. SUMMARY OF THE INVENTION The main object of the present invention is to change the precursor The relative relationship between the molar ratio, the solvent content, the reaction time and the reaction temperature, and the specific surface area of the parameter, find out the important optimal operation, and synthesize the metal organic framework crystal condition with high specific surface area. 'In the experimental conditions of this experiment, the optimal reaction time can be shortened not only at a higher reaction temperature but also at 12 ° C for 12 hours to rapidly synthesize the metal organic skeleton crystal 200925162 with a specific surface area higher than 3000 m 2 /g. And this condition further increases the yield. At this temperature 丨2 (the TC condition, if the reaction time is lower or higher than 12 hours, the crystal quality of the metal organic skeleton is formed. The specific surface area of the present invention is greatly reduced. The secondary object of the present invention is that it has high heat stability and high crystallinity after storage treatment, and can be placed in a dry environment without being easily decomposed. A method for rapidly synthesizing and preserving a metal-organic framework with a high specific surface area, selecting the zinc nitrate and bismuth as the precursor of the stearic acid, and according to the Mohr ratio of each other, In a base amide solvent, a precursor solution is prepared, and the precursor solution is placed in a glass bottle, and the sample is heated by a hot solvent method at a heating rate of 2 ° C /min. And after heating to 120 ° C, 12 hours of constant temperature treatment to precipitate a metal organic skeleton crystal Zri4 〇 (BDC) r (DEF) x, after the metal organic skeleton crystal is cooled to room temperature at a cooling rate of 1.6 ° C / min, The metal organic skeleton crystal of Zn4〇(BDC)3.(CHCl3)x can be obtained by washing with the dimercaptocarboxamide solvent and replacing it with a trioxane (Chloroform, chci3). (Yaghi et al., 1998) proposed ' Remove the impurities and solvent in the material hole, and heat it at 140 °C under vacuum (5xl0·5 Torr) for up to 16 hours. 'This work proposes a preservation method' for heating under a vacuum and low pressure environment. Under the condition of temperature 180~200 °C, the reaction time is only 3 hours, the material can be activated, and the impurities in the pores of the material can be effectively removed and the 200925162 agent can be dissolved. The more important 疋 also increases the structural stability and elongation of the material. [Embodiment] 实施 Refer to the "Fig. 1 and Fig. 2" for the production flow diagram of the present invention and the heating diagram of the present invention. As shown in the figure: The present invention is a method for rapid synthesis and preservation of a metal-organic framework having a high specific surface area, which comprises at least the following steps: (A) Formulation of a precursor solution ii: Selection of zinc nitrate (Ζη(Ν03)2· 4Η20) and a pair of phthalic acid (H2BDC) as precursors, and dissolved in monoethylformamide (DEF) solvent according to the molar ratio of zinc nitrate to the terephthalic acid Forming a precursor solution, wherein the molar ratio of the zinc nitrate to terephthalic acid can be 1:1, 2:1, 3:1 and 4:1; (B) heating by a hot solvent method丄2: As shown in Fig. 2, the precursor solution 2 1 is placed in a glass bottle 2 2, and the glass bottle 22 is directly placed in a heating pack 3 by a hot mash method. A controller 3 heats the heating pack 3 i, inserts a temperature sensor 3 2 on the glass bottle 2 2 port, and seals it tightly, and performs feedback control by the temperature sensor 3 2 to 2. Heating the glass bottle 22 from room temperature to 120 ° C at a heating rate of 〇 (° C / min), wherein the heating package 3 1 automatically stops heating when the set temperature 12 〇〇 c is reached. 200925162 (c) Constant temperature treatment and synthesis of metal-organic framework crystals 1 3: heating to 120 ° C for 12 hours of strange temperature treatment to synthesize a metal-organic framework crystal with cubic three-dimensional porous structure (Zn4 〇(BDC)3*(DEF)x, MOF-5), and the chemical reaction formula of the metal organic skeleton crystal is: 4Zn2+ + 3H2BDC - Zn40(BDC)3 (DEF)X; and (D) preservation treatment 14: The metal organic skeleton crystal was cooled to room temperature, washed with a solvent of dimethyl decylamine (DMF), and then replaced with trichloromethane (CHC13), as follows: Zn, 0 {BDC\ ·(DEF)X-^β->Ζ«40(5Ζ)〇3 (CHCl3)x Finally 'cleaned and replaced metal-organic framework crystals (Zn40) in a low or general vacuum environment (BDC) 3. (CHCl3)x) ' The sample was activated for 1 to 3 hours between 18 〇〇C and 200 °C. In the above method, when the molar ratio of zinc nitrate, terephthalic acid to diethylformamide is 3:1:225, the reaction temperature is 90 to 120 C, and the reaction time is 16 to 72 hours. , the resulting crystal

The Langmuir specific surface area can be higher than 丨〇〇〇m2/g. By changing the reaction temperature and time, a metal framework material with a specific surface area higher than 3 〇〇〇 m2/g can be obtained. Therefore, in order to obtain the high specific surface area and the yield of the metal-organic framework crystal, the work is carried out, and the reaction is carried out at a reaction temperature of a high reaction temperature of 120 ° C and a constant constant temperature of 12 hours. The acidity, the molar ratio of the terephthalic acid to the diethyl amylamine are optimal at 3:1:225, and not only can be prepared 12 200925162

The Langmuir metal organic framework material with a specific surface area of 3113 m2/g can reduce the required reaction time compared to previous studies, and at the same time achieve an effect of improving the yield. The theoretical ordered crystal structure of the synthesized MOF-5 material is closely related to its high specific surface area. Generally, the synthesis parameters such as reaction time, reaction temperature and molar ratio will affect the crystal structure (quality). It is possible to grasp the influence of the process parameters through the identification instrument analysis method. Therefore, the X-ray diffraction method is the fastest method to identify whether it has the correct structure. The synthetic parameters are not under the optimal conditions, and the X-ray of the crystal is synthesized. The diffraction pattern is anomalous (the diffraction peak angle and relative intensity do not correspond to the theoretical calculation), so the empirical measurement of the specific surface area will be less than 1000 m2/g. Therefore, the prepared metal organic skeleton crystals are first subjected to X-ray diffraction analysis as a preliminary quality test, and then a scanning electron microscope (SEM) is used to observe whether the morphology has an abnormal cube. As a secondary test of the second step, the specific surface area value was measured by a specific surface area analyzer (Brunauer-Emmett-Teller, BET). Please refer to the "Fig. 3" for a PXRD pattern and a SEM photograph of the present invention (MOF-5 product). As shown in the figure: the diffraction peak angle and phase intensity of the PXRD measurement spectrum of the metal organic framework material prepared by the invention are consistent with the theoretically calculated PXRD pattern of Yaghi, the crystal phase belongs to the Fm3m structure, and the surface is a simple cube. The type has a lattice constant of 25 A and a crystal width of about 10 to 100 μ 13 200925162 m (μπι). The hydrogen storage capacity of the metal organic framework material has a great relationship with the ambient temperature and pressure. It is inferred from the PXRD pattern that the material will have a hydrogen storage capacity of 4.7 wt% at 77 Κ and 5.0 MPa. On the other hand, the composite material utilizes high pressure heat. The weight analyzer (HPTGA) measured its hydrogen storage capacity at room temperature and 7.0 MPa at 0.27 wt ° / 〇, which is equivalent to other literature measurements. For specific surface area analysis, please refer to Figure 4, which is a schematic diagram of the adsorption-desorption isotherm analysis of the specific surface area analyzer of the present invention. As shown in the figure: The metal-organic framework material prepared by the invention belongs to the type_I type and belongs to the micropore material. Please refer to Fig. 5 for a schematic diagram of the PXRD pattern change of the MOF-5 sample of the present invention without preservation treatment and storage treatment. As shown in Fig. 5, the PXRD pattern of the MOF-5 material was changed before and after the preservation treatment, and the sample was compared with the PXRD pattern of (1) and (3) of Fig. 5, and the sample was stored in a low vacuum for 39 days. The main peak of 6.9° diffraction peak of MOF-5 decreases, and many diffraction peaks of impure phase are added, which shows that the sample has general phase decomposition. According to the PXRD pattern of Fig. 5(1)(2), the sample is preserved. After storage for 39 days under low vacuum, the main diffraction peak position of M0F-5 was still at 6.9° and 9.6°, and no other characteristic characteristics of the impure phase were generated. 200925162 In summary, the present invention is a rapid synthesis and preservation method of a metal-organic framework with a high specific surface area, which can effectively improve various disadvantages of the prior art by changing the molar ratio, solvent content, reaction time and reaction temperature of the precursor. The relative relationship between the parameter factors and the surface area, the metal organic framework material with high specific surface area can be synthesized quickly, not only can shorten the reaction time at high reaction temperature to improve the yield, but also increase the structural stability after the preservation treatment. It also extends the preservation period, so that the invention can be made more progressive, more practical, and more suitable for the user. It has indeed met the requirements of the invention patent application, and the patent application is filed. However, the above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto; therefore, the simple equivalent changes and modifications made by the scope of the invention and the contents of the invention are 'All should remain within the scope of this patent. ❹ 15 200925162 [Simplified description of the drawings] Fig. 1 is a schematic diagram of the production process of the present invention. Figure 2 is a schematic view of the heating of the present invention. Figure 3 is a schematic diagram of PXRD and SEM analysis of the present invention. Fig. 4 is a schematic diagram showing the strange temperature adsorption-desorption curve of the specific surface area analyzer of the present invention. Fig. 5 is a schematic view showing the change of PXRD before and after the preservation treatment using the M0F_5 sample of the present invention, without preservation treatment. [Description of main component symbols] Step (A) is formulated into a precursor solution 1 1 Step (B) is heated by a hot solvent method 1 2 Step (C) is subjected to constant temperature treatment to synthesize a metal organic skeleton crystal 1 3 Step (D) Carry out the process 14 ® Precursor solution 2 1 Glass bottle 2 2 Controller 3 Heat pack 3 1 Temperature sensor 3 2

Claims (1)

200925162 X. Patent application scope: 1 · A method for rapid synthesis and preservation of a metal-organic framework with a specific surface area, which comprises at least the following steps: (A) selecting zinc nitrate (Ζη(Ν〇3)2·4Η2〇) and one Terephthalic acid (HaBDC) is a precursor and is dissolved in monoethylformamide (DEF) solvent to form a precursor according to the molar ratio of zinc nitrate to the terephthalic acid. The solution is placed in a glass bottle, and the glass bottle is heated by a hot solvent method; after heating, it is subjected to constant temperature treatment to synthesize a metal organic skeleton crystal (Zn4〇(BDC)3. DEF)x^ and (B) After cooling the metal organic skeleton crystals to room temperature, the solvent is washed with =dimethyl dimethylformamide (DMF), and then replaced with monohydromethane (CHCI3). Finally, The temperature is stored between ~200 °C and the sample is activated for ~3 hours. 2 · The rapid synthesis and preservation method of the metal-organic framework with high specific surface area according to the scope of the patent application, wherein 'the zinc nitrate and The molar ratio of the terephthalic acid can be 1 : 1, 2: 1, 3: 1 and 4' factory 3. A method for rapid synthesis and preservation of a metal-organic framework having a high specific surface area according to the scope of the patent application, wherein the hot solvent method is a glass bottle Directly placed in a heating pack, the heating pack is heated by a controller, and a temperature sensor is inserted into the glass bottle mouth and sealed tightly, and the temperature sensor is used for feedback. 17 200925162 Control When the set temperature is reached, the heating package is self-stopping. τ 4· The high specific surface area metal according to the third claim of the patent application has a rapid skeleton synthesis and preservation method, wherein the heating package is Heating at room temperature to l2〇〇c at a heating rate of 2 ° C / min. 5 · Rapid synthesis and preservation of metal-organic framework with high specific surface area as described in the scope of application of the patent application, wherein the strange temperature The treatment is carried out at a constant temperature of 120 ° C for 12 hours. 6 · According to the patent application scope, the high specific surface area of the high-specific surface area of the gold machine skeleton rapid synthesis and preservation method '纟, the preservation treatment is the metal organic skeleton crystal On i 8〇〇c~ 2 Under low temperature vacuum environment between the 〇〇c 'is Bu sample activation for 6 hours.