A New Porphyrin-based Covalent Organic Framework with High Iodine Capture Capacity and I-doping Enhanced Conductivity

Covalent organic frameworks (COFs) are porous organic materials with well-defined and uniform structure. The material is an excellent candidate as a solid adsorbent for iodine adsorption. In the present study, we report the synthesis of COF with porphyrin moiety, TF-TA-COF, by solvothermal reaction, which was characterized by XRD, solid-state 13C NMR, IR, TGA, and nitrogen adsorption-desorption analysis. TF-TA-COF showed a high specific surface area of 443 m2 g-1, and exhibited good adsorption performance for iodine vapor, with an adsorption capacity of 2.74 g g-1. XPS and Raman spectrum indicated that a hybrid of physisorption and chemisorption took place between host COF and iodine molecules. The electric properties of iodine-loaded TF-TA-COF were also studied. After doped with iodine, the conductivity of the material increased by more than 5 orders of magnitude. The photoconductivity of I2-doped COF was also studied and TF-TA-COF showed doping-enhanced photocurrent generation. A novel COF was prepared. Structure of the COF was characterized by PXRD, TEM, BET and CV et al. Theoretical simulation fit well in with experimental data, including XRD profile, layer distance, pore size and HOMO/LUMO energy level. The material showed high iodine capture capability and interaction between iodine and framework was studied. After iodine-doping, enhanced conductivity was observed.image