Abstract
In this work, we investigate the lone pair (lp)center dot center dot center dot pi interaction for the halogens (X-2 = I-2, Br-2, Cl-2, and F-2) binding to the rGO surface. Electronic and optical properties of rGO significantly tuned upon adsorption of halogen molecules, although the weak nature of (lp) center dot center dot center dot pi forces. The structure and optical properties of rGO, rGOI(2), rGOBr(2), rGOCl(2) and rGOF(2) adducts were investigated by density functional theory (DFT) and time-dependent DFT (TD-DFT) method. Halogen molecules (X-2) stable structures were planer on rGO surface and stabilized by the lone pair X-2 (lp)center dot center dot center dot pi(C) interactions. The surface oxygen atoms contributed to the stability by the O(lp)center dot center dot center dot pi(X-2) charge transfer process. Bader analysis reveals significant charge transfer and bond length elongation for X-2 on rGO monolayer sheet in the order I-2 > Br-2 > Cl-2 > F-2. Surface adsorption of X-2 molecules on rGO surface tunes both band gap energy and optical properties. The TDOS and PDOS reveal that X-2 adsorption on rGO surface forms an intermediate states in band gap region, which decrease the energy values. These results are beneficial for photocatalysis and light harvesting applications. (c) 2021 Elsevier B.V. All rights reserved.