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 (H 2BDC-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 m 2 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 BDC 2--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. Would I Li to you: Li doping into hydroxy-modified MOF-5 (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 to 5.5-4.4 kJ mol-1).
- metal-organic frameworks
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