Adsorption properties of amino acid-based ionic liquids (AAILs) on edge fluorinated graphene surface – a DFT study

ABSTRACT

We have investigated the adsorption properties of amino acid-based ionic liquids (AAILs) on edge fluorinated graphene surface (FG). Adsorption of organic ILs on the FG surface occurs via hydrogen bonds (X-H···FC), electrostatic interactions, and π···π interactions. There are large charge transfers between the interfaces, primarily from the lone pair of the fluorine (C-F bond) to the X-H (X = C, N, O) bond of both cations/anions AAILs. These non-conventional reversible hydrogen bridges are essential in surface interactions. However, substantial charge transfer occurs to cations and anions in both aromatic and aliphatic systems, respectively. Interestingly, aromatic AAILs are firmly physisorbed than aliphatic ILs. The inclusion of dispersion corrections increases the accuracy of total binding energy contributions from multiple adsorption interactions and predicts the complex's kinetic stability. Molar volume values determine the materiality of AAIL/FG to bulk systems.

KEYWORDS:

• DFT
• ionic liquid
• graphene
• fluorine

Acknowledgment

Authors Dr. Senthilkumar Lakshmipathi and Mrs. Shyama Muraledharan gratefully acknowledge the DST-SERB, New Delhi, India, for granting the project and fellowship (EEQ/2016/000331).

Disclosure statement

The authors declare no competing interests.

Supporting information

The ESP, RDG, and correlation plots for AAIL adsorption on the FG surface along with optimized geometry coordinates in standard format are given in the supporting information.

Additional information

Funding

This work was supported by Science and Engineering Research Board: [Grant Number EEQ/2016/000331].