Facile Synthesis of Hydroxy‐Modified MOF‐5 for Improving the Adsorption Capacity of Hydrogen by Lithium Doping |
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| Authors: | Dr Masaru Kubo Hayato Hagi Prof?Dr Atsushi Shimojima Prof?Dr Tatsuya Okubo |
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| Institution: | 1. Department of Chemical System Engineering, The University of Tokyo, 7‐3‐1 Hongo, Bunkyo‐ku, Tokyo 113‐8656 (Japan), Fax: (+81)?3‐3800‐3806;2. Current address: Department of Chemical Engineering, Hiroshima University, 1‐4‐1 Kagamiyama, Higashi Hiroshima, Hiroshima 739‐8527 (Japan);3. Current address: Mines ParisTech, CEP‐Centre Energétique et Procédés, 60 Boulevard Saint Michel, 75006 (France);4. Current address: Department of Applied Chemistry, Waseda University, 3‐4‐1 Ohkubo, Shinjuku‐ku, Tokyo 169‐8555 (Japan) |
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| Abstract: | A facile synthesis of partially hydroxy‐modified MOF‐5 and its improved H2‐adsorption capacity by lithium doping are reported. The reaction of Zn(NO3)2 ? 6 H2O with a mixture of terephthalic acid (H2BDC) and 2‐hydroxyterephthalic acid (H2BDC‐OH) in DMF gave hydroxy‐modified MOF‐5 (MOF‐5‐OH‐x), in which the molar fraction (x) of BDC‐OH2? was up to 0.54 of the whole ligand. The MOF‐5‐OH‐x frameworks had high BET surface areas (about 3300 m2 g?1), which were comparable to that of MOF‐5. We suggest that the MOF‐5‐OH‐x frameworks are formed by the secondary growth of BDC2?‐rich MOF‐5 seed crystals, which are nucleated during the early stage of the reaction. Subsequent Li doping into MOF‐5‐OH‐x results in increased H2 uptake at 77 K and 0.1 MPa from 1.23 to 1.39 wt. % and an increased isosteric heat of H2 adsorption from 5.1–4.2 kJ mol?1 to 5.5–4.4 kJ mol?1. |
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| Keywords: | adsorption doping hydrogen lithium metal– organic frameworks |
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