Aqueous-Phase Confined Assembly of Single-Atom Chains inside Carbon Nanotubes Enabling Ultrafast Iodine Removal and...

Extracting radioactive iodine from waste solutions and directly converting it into functional materials with controllable structures is crucial. We report a liquid-phase strategy for confined assembly of single-atom iodine chains inside single-walled carbon nanotubes (SWCNTs). SWCNTs with diameters of 0.7-2.2 nm predominantly host single-atom chains, enabling charge transfer from tube walls to chains, forming I3- units and inducing positive charge delocalization on the tube surface, which is more pronounced in larger diameters. This charge delocalization makes large-diameter SWCNTs robust adsorbents for rapid iodine removal via electrostatic interactions across broad temperature (2-60 °C) and pH (1-5.6) ranges, achieving an exceptional removal rate (53.7 mgI2·gSWCNT-1·min-1) surpassing most reported adsorbents and enabling continuous-flow capture. The single-atom chain Ix@SWCNT also serves as a highly efficient and stable catalyst for thiol coupling, boosting the reaction rate 21-fold over homogeneous molecular I2. Spectroscopy and calculations elucidate the charge delocalization mechanism within Ix@SWCNT.