CoCorrole-Functionalized PCN-222 for Carbon Monoxide Selective Adsorption

Abstract

The high risk of CO poisoning justifies the need for indoor air quality control and warning systems based on the detection of low concentrations (ppm-ppb) of CO. Cobalt corrole complexes selectively bind CO vs. O₂, CO₂, N₂, opening new fields of applications. By combining the CO chemisorption properties of cobalt corroles with the known sorption capacity of MOFs, we hope to obtain high performance sensing materials for CO detection. In addition, the exposed metal sites of MOFs lead to CO₂ physisorption, allowing the co-detection of CO and CO₂. In this work, PCN-222, a stable Zr-based MOF made from Ni(TCPP) with natural vacancies, has been used as a porous matrix for the grafting of electron-poor metallocorroles. The materials were characterized by powder XRD, SEM and optical microscopy, BET analyses and gas adsorption measurements at 298 K. No degradation of the crystalline structure of PCN-222 was observed. At 1 atm, the adsorbed CO_(g) volumes measured for the best materials were 12.15 cm³ g^-1 and 14.01 cm³ g^-1 for CoCorr2@PCN-222 and CoCorr3@PCN-222 respectively, and both materials exhibited high CO chemisorption and selectivity against O₂, N₂, and CO₂ at low pressure due to the highest energy of the chemisorption process vs physisorption.

Keywords: Carbon dioxide; Carbon monoxide; Cobalt corrole; Gas detection; Metal-organic framework; Reversible adsorption.