Adsorption of Nitrogen Dioxide in a Redox-Active Vanadium Metal-Organic Framework Material

Nitrogen dioxide (NO₂) is a toxic air pollutant, and efficient abatement technologies are important to mitigate the many associated health and environmental problems. Here, we report the reactive adsorption of NO₂ in a redox-active metal-organic framework (MOF), MFM-300(V). Adsorption of NO₂ induces the oxidation of V(III) to V(IV) centers in MFM-300(V), and this is accompanied by the reduction of adsorbed NO₂ to NO and the release of water via deprotonation of the framework hydroxyl groups, as confirmed by synchrotron X-ray diffraction and various experimental techniques. The efficient packing of {NO₂·N₂O₄}_∞ chains in the pores of MFM-300(V^IV) results in a high isothermal NO₂ uptake of 13.0 mmol g^-1 at 298 K and 1.0 bar and is retained for multiple adsorption-desorption cycles. This work will inspire the design of redox-active sorbents that exhibit reductive adsorption of NO₂ for the elimination of air pollutants.