Adsorption of 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) on pristine, defected and Al-doped carbon nanotube: A dispersion corrected DFT study

The effective enrichment and detection of organic pollutants in the environment has been attracted much attention because of enormous concerns about human health. Using dispersion-corrected density functional theory (DFT-D2), the interactions between 2, 3, 7, 8-tetrachlorodibenzo-p-dioxin (TCDD) and pristine, defected and Al-doped carbon nanotubes (Al-CNT) were studied. The TCDD molecule was physisorbed on a pure CNT and CNT contain defects with binding energies of about −0.52 eV and −0.34 eV, respectively. The accuracy of our method was validated by hybrid B3LYP levels of theory and it was shown that there is a worthy agreement between two respected methods. However, the binding energy rises to −0.85 eV when TCDD binds to Al-CNT. The increase in binding energy is due to charge transfer from the TCDD molecule to the Al-CNT. Furthermore, the obtained DOS spectra and total charge density indicates that the electronic properties of Al-CNT change considerably by the adsorption of TCDD whereas no such variations are observed for other considered CNTs. Consequently, the Al-CNT is a promising candidate for the TCDD sensing and detection. Our first-principles results present evidences for a rational benchmark for the applicability of the Al-CNT for TCDD adsorption and detection.