Achieving Sub‐ppm Sensitivity in SO <sub>2</sub> Detection with a Chemically Stable Covalent Organic Framework
Wei Zhao, Juan L. Obeso, Valeria B. López‐Cervantes, Mounib Bahri, Elí Sánchez‐González, Yoarhy A. Amador‐Sánchez, Junyu Ren, Nigel D. Browning, Ricardo A. Peralta, Giovanni Barcaro, Susanna Monti, Diego Solís-Ibarra, Ilich A. Ibarra, Dan Zhao
Abstract
Abstract We report the inaugural experimental investigation of covalent organic frameworks (COFs) to address the formidable challenge of SO 2 detection. Specifically, an imine‐functionalized COF (SonoCOF‐9) demonstrated a modest and reversible SO 2 sorption of 3.5 mmol g −1 at 1 bar and 298 K. At 0.1 bar (and 298 K), the total SO 2 uptake reached 0.91 mmol g −1 with excellent reversibility for at least 50 adsorption‐desorption cycles. An isosteric enthalpy of adsorption (Δ H ads ) for SO 2 equaled −42.3 kJ mol −1 , indicating a relatively strong interaction of SO 2 molecules with the COF material. Also, molecular dynamics simulations and Møller–Plesset perturbation theory calculations showed the interaction of SO 2 with π density of the rings and lone pairs of the N atoms of SonoCOF‐9. The combination of experimental data and theoretical calculations corroborated the potential use of this COF for the selective detection and sensing of SO 2 at the sub‐ppm level (0.0064 ppm of SO 2 ).