A Density Functional Theory Study of Adsorption Ethionamide on the Surface of the Pristine, Si and Ga and Al-Doped Graphene

In this research, the adsorption behavior of pristine, Si- and Ga- and Al-doped graphene is investigated toward ethionamide (EA) using Density Functional Theory (DFT) calculations. Total energies, and geometry optimizations were obtained and Density of State (DOS) analysis was performed at B3lyp level of theory with the 6-31G* basis set. The adsorption energy (Ead) between EA and the pristine, Si-, Ga- and Al-doped graphene is changed in the following order: Ga-Complex-N(ring) > Al- Complex-N(ring) > Si-Complex-N(ring) > Complex-S. The Ead of the Graphene-EA complex is -2.552 kcal/mol, which is low and shows that the adsorption is physical. The % ΔEg= -59.61% for Si-doped graphene EA shows the high sensitivity of the Si-doped graphene to the adsorption of EA. The Eg for Ga-doped graphene-EA decreases significantly from 2.35 to 1.11 eV and the rate of change is %ΔEg = -52.75%, showing the high sensitivity of Ga-doped graphene to the adsorption of EA. However, the high Ead of -36.66 kcal/mol shows that the Ga-doped graphene can be used as a suitable sensing device only at higher temperatures. The % ΔEg= -58.98 % for Al-doped graphene-EA indicates the high sensitivity of the Al-doped graphene to the adsorption of EA. The Ead of -34.53 kcal/mol can be used as a suitable sensing device only at higher temperatures.