Orientated growth of copper-based MOF for acetylene storage

Manipulating crystal growth of metal-organic frameworks (MOFs) has great potential in achieving unique properties for adsorption, separation and catalysis applications. For the first time, we used Mg/Al layered double hydroxide (LDH) nanosheets as modulators to tune the growth orientation of HKUST-1 without either pore blockage or crystallinity degradation. Through the introduction of LDH during hydrothermal process, HKUST-1 crystal shape transfers from octahedron with fully exposed {1 1 1} facets to tetrakaidecahedron with both {1 0 0} and {1 1 1} facets. The exposure of {1 0 0} facet with large pore size facilitates the activation of MOF, thereby providing more open metal sites. As a result, the micropore volume and BET surface area increase remarkably from 0.75 cm3/g to 1.01 cm3/g and 2255 m2/g to 3001 m2/g, respectively. The tetrakaidecahedral HKUST-1 exhibits high acetylene uptake of 275 cm3 (STP)/g at 298 K and 1 atm, which is the highest value ever reported to the best of our knowledge.