Adsorption of aromatic molecules on a black phosphorene surface: a first-principles study

Abstract

Investigating the adsorption of aromatic molecules on different surfaces has been of interest due to their use in industrial catalytic processes, as well as the polluting nature of some of them. In this work, the adsorption of benzene, benzoic acid, benzoyl chloride, benzaldehyde, aniline, benzonitrile, and 4-chlorobenzoic acid on a black phosphorene surface was studied using the density functional theory. Investigation into using different non-local correlation functionals showed that the vdW-DF functionals led to a higher binding energy than the vdW-DF2 functionals. Also, these functionals led to a lower Fermi energy. Benzene and 4-chlorobenzoic acid showed the weakest and strongest interaction with the surface with an adsorption energy of −0.653 and −0.996 eV, respectively. Furthermore, the work function changes during the adsorption process show the capability of the surface to be used as a sensor for aromatic molecules. Surface doping with the S atom and its effect on the adsorption of 4-chlorobenzoic acid revealed that this surface with a metallic characteristic still has the ability to adsorb aromatic molecules with a slightly higher binding energy. The plots of the non-covalent interaction index confirm the vdW interaction between the aromatic molecule and the BP or S-doped BP surface. The total molecular PDOS indicates the overlapping of the adsorbed molecule and the surface orbital. Also, the charge density difference plots clearly demonstrated the charge transfer from the phenyl ring atoms and accumulation between the functional group and the surface. The present study reveals the capability of black phosphorene as a promising material for sensing or removing aromatic molecules.