A nanosized metal-organic framework confined inside a functionalized mesoporous polymer: an efficient CO2 adsorbent with metal defects

Hybrids with a nanosized metal-organic framework (MOF) confined within a mesoporous structure have attracted increasing attention owing to their enhanced mass transfer and novel applications. However, effective control of MOF crystal growth within pores and further understanding of the structure-property relationship are challenging. Herein, we report the confinement of a nanosized metal-organic framework CAU-1 into a functionalized mesoporous polymer via a combined impregnation and solvent vapor growth process. Carbonyl and hydroxyl groups over the wall of the mesoporous polymer well boost the nucleation and growth of CAU-1, leading to the formation of a nanosized MOF inside the mesoporous polymer. In contrast to bulk CAU-1, the nanosized CAU-1 within the hybrid exhibits significantly enhanced CO2 adsorption capacity at low pressure. As confirmed using the Al-27 MAS NMR characterization technique, the confined nanosized CAU-1 is rich in aluminium defects. The improved CO2 adsorption properties probably result from the favorable diffusion kinetics and the presence of metal defects as active binding sites.