Abstract:
The harmful chemicals like chemical warfare agents (CWAs) and toxic industrial
chemicals (TICs) are extremely pernicious to the climate and living systems. The efficient
detection and removal of these noxious chemicals in limited time span is essential for the
human health and environmental security. Twisted nanographenes have great applications
in the fields of energy storage and optoelectronics, but their applications as sensors are
rarely described. Therefore, we have explored theoretically the sensitivity and selectivity
of twisted nanographenes C32H16, C64H32 towards the harmful chemicals like phosgene,
thiophosgene and formaldehyde. Here, we elaborate the phenomena of adsorption of the
selected toxic chemicals on twisted nanographenes' surface within the framework of
density functional theory (DFT). Adsorption interpretation is depending upon the
optimized geometries, adsorption energies, NBO (natural bond orbital) charge transfer,
frontier molecular orbital (FMO), absorption (UV-Vis), NCI (non-covalent interaction)
and QTAIM (quantum theory of atoms in molecules) analyses. Results of interaction
energies reveal the physiosorption of the toxic chemicals on the twisted nanographenes
surface, which mainly arise due to the non-covalent interactions. The non-covalent nature
of adsorption of toxic chemicals on twisted nanographenes surface is also ascribed by the
NCI and QTAIM analyses. Most favorable adsorptions of the selected toxic chemicals
occur at the edges of the distorted moiety (central ring). The average band gap changes
(%Eg) and %sensitivity is quantitatively determined by the molecular orbital analysis, to
evaluate the sensitivity of twisted nanographenes. Among the selected chemicals, the
sensing of thiophosgene (ThP) is prominent on the twisted nanographenes surface, having
interaction energies of -8.19 and -12.14 kcal mol-1 (in case of C32H16 and C64H32 tNGs),
respectively. Therefore, it is concluded that twisted nanographenes can be applied as a
potential sensing agent for the detection of toxic chemicals, especially thiophosgene. Thisx
research will help the experimentalists to devise novel sensors based on twisted
nanographenes.
