Heteroatoms (B, N, and P) doped on nickel-doped graphene for phosgene (COCl2) adsorption: insight from theoretical calculations

Abstract

Nanomaterials have been used for different applications including sensing environmental gases. Exposure to hazardous gas in the environment leads to major health issues such as swelling throats, delayed nervous system responses, and many more. Similarly, the development of sensors for fast environmental COCl2 monitoring is currently necessary. In this work, a molecular study on the adsorption of COCl2 onto metal-doped graphene nanoflakes and the heteroatom-decorated graphene nanoflakes (Ni, B, N, and P) has been computed using the density functional theory method at the ωB97XD/6-311 + G (d, p) level of computation. Total density of state analysis shows that the Ni-doped and decorated (B, N, P) surfaces decrease the HOMO-LUMO energy gap and therefore have a significant influence on the electric properties of the surfaces. The deviation in bond length on complexation with gas molecules infers that surfaces can adsorb COCl2 gas. In our work, two configurations are used: sites Cl and O. From our result for adsorption energies, it is observed that COCl2 is better adsorbed on the metal-doped graphene than the heteroatom-decorated graphene with an adsorption energy of −6.466 eV at orientation O-atom site. The calculated adsorption energies indicate that at site Cl of the COCl2 gas is physisorbed and chemisorbed at site O. The adsorption energy is in the order of GP_Ni > GP_NiP > GP_NiB > GP_NNI. The order of decreasing stabilization energy is as follows: GP_NiB > GP > GP_Ni > GP_NiN > GP_NiP; this contributes to the stability of adsorbent materials. The quantum theory of atom in molecules and non-covalent interaction analysis validate that the interaction between COCl2 and model surfaces is more non-covalent. Therefore, studied graphene nanoflake models can adsorb COCl2 gas molecules and can be considered an effective gas-sensing material.