Abstract
Hybrid ultramicroprous materials (HUMs) with a number of different variations of the inorganic pillars as well as surface functional groups have been tested as CO2 sorbent for low-concentration CO2 capture. Specifically well-known HUM NbOFFIVE-1-Ni (NbOFFIVE=(NbOF5)2-, 1=pyz, Ni=nickel(II)) like HUMs were synthesized in this study by replaces Nb with V and Ta. Replacing the metal center from Nb to V or Ta showed that the CO2 adsorption isotherm, in particular at low partial pressures, adopted different shapes and gradient. This study shows that the CO2 adsorption properties at low partial pressures on HUMs can be affected by the metal present in the inorganic pillars.