Nitrobenzene detection using pristine and transition metal-decorated C[18] cyclocarbon: A first-principles density functional theory study

Abstract

Carbon-based nanomaterials have been extensively used for gas or biomolecule sensing applications in recent years. Nitrobenzene (NB) is one of the major environmental pollutants, and its excessive discharge into the atmosphere is a serious menace to all living beings. Hence, effective sensing of the NB is required. In the present work, we have studied the NB adsorption properties of the recently discovered allotrope of carbon, cyclocarbon (C[18]), and transition metal (TM = Sc, Ti, and Cr)-decorated C[18] using the density functional theory method. The NB molecule is physisorbed on the pristine C[18] with a low adsorption energy of −0.49 eV. Among the three TMs, the Sc and Ti atoms strongly bind on the cyclocarbon with a binding energy of −2.47 and −1.87 eV, respectively, resulting in an improvement in the conductivity of the pristine C[18]. NB adsorption on the Sc-decorated system is found more favorable, with a considerably larger adsorption energy of −2.993 eV than the pristine C[18]. The improved adsorption is due to the orbital interaction and the charge transfer of 0.562e from the Sc 3d orbitals to the O 2p orbitals of the NO2 group in NB. This work could provide a theoretical foundation for developing a potentially novel NB sensor based on the TM-decorated C[18] cyclocarbon.