Hierarchically structured metal-organic framework/vertically-aligned carbon nanotubes hybrids for CO2 capture

A novel carbon/metal-organic framework composite was synthesized by confined growth of HKUST-1 in the interspace of the vertically-aligned carbon nanotube (VACNT) arrays. The grown HKUST-1 crystals are much smaller than the HKUST-1 crystals produced without the confinement growth. The derived HKUST-1/VACNT hybrids possess a hierarchical microporous-mesoporous structure. In comparison to the calculated hypothetical value assuming the physical mixture of the components, the synthesized HKUST-1/VACNT composites exhibit larger surface area and porosity, higher CO2 adsorption amount, and better CO2/N-2 selectivity, which indicate the positive synergistic effect between HKUST-1 and VACNT. Besides the superior adsorption properties of hybrids, they are easier to handle than powder adsorbent for gas storage/separation.