An explanation for the very large breathing effect of a metal-organic framework during CO2 adsorption

The unusual adsorption behavior of CO2 in a nanoporous hybrid metalorganic solid is discussed (see figure). The results indicate that the gas adsorption-desorption step is related to a breathing phenomenon. This study also suggests that the main interactions responsible for the breathing phenomenon are strong guest-framework CO2-OH interactions as well as CO2-CO2 interactions along the tunnels present in the structure.