Metal‐containing hydrogen‐bonded organic frameworks with alternating electrostatic environments for trace SO 2 capture

Abstract Trace SO 2 capture from flue gas remains challenging in deep desulfurization because of its low partial pressure, corrosive conditions, and competition from coexisting gases. Here, we present a family of isostructural metal‐containing hydrogen‐bonded organic frameworks (M‐HOFs) featuring alternating electrostatic pore environments for efficient trace SO 2 capture. All M‐HOFs exhibit SO 2 uptakes higher than 2.76 mmol g −1 at 0.2 kPa and 298 K, while Ni‐HOF delivers a SO 2 packing density of 3.23 g cm −3 at 100 kPa, surpassing that of solid SO 2 . M‐HOFs show high SO 2 /CO 2 selectivities (>600 for a 0.2/99.8 mixture) and low uptakes of CH 4 , N 2 , and O 2 , enabling efficient deep desulfurization under simulated flue‐gas conditions. Breakthrough and cycling experiments at SO 2 concentrations of 2000–3000 ppm confirm robust deep‐desulfurization performance, highlighting M‐HOFs as promising adsorbents for practical SO 2 removal. Crystal structure and spectroscopic analyses support cooperative host‐guest interactions within confined micropores lined by alternating positive and negative electrostatic sites.