Iodine nanotrap for highly efficient iodine capture under high temperature.

[Display omitted] • The I 2 nanotraps were used by introducing adjacent IBSs and LBSs on the skeleton. • The absorbent shows high I 2 uptake capacity (37 wt%) among all COF materials. • IBSs and LBSs synergistically promote iodine adsorption. Covalent organic frameworks have been recognized as promising porous materials for the radioactive iodine capture. However, most COFs often suffer from low adsorption capacity under practical conditions (typically ≥ 150 °C, ≤ 150 ppmv I 2) due to the lack of strong binding sites and low affinity toward iodine, which restricts their application in industrial relevant conditions. Here, we develop a strategy of constructing highly efficient I 2 nanotraps by manipulating two kinds of adsorption sites (ionic binding sites and Lewis binding sites) located at adjacent spatial positions, thereby realizing the synergistic binding toward I 2. The obtained I 2 nanotrap 4F-iCOF-TpBpy-I- delivers a remarkable I 2 uptake capacity of 37 wt% at 150 °C and 150 ppmv of I 2 , which illustrate a record-high value for all COFs reported so far. This work opens a new avenue for the rational design of COF materials toward highly efficient I 2 capture and related application. [ABSTRACT FROM AUTHOR]