Nitrogen mono-doping of graphene and co-doping with group 14 as a sensor for diisobutyl phthalate: Insight from a computational study

Abstract

Diisobutyl phthalate (DIBP) is a highly toxic plasticizer found in edible consumer products and industrial products. It affects the male reproductive system, bioaccumulates in water, and poses health risks. Given its widespread occurrence, designing novel sensor materials for sensing of DIBP is necessary for environmental and health safety. In this research, density functional theory (DFT) at the DFT/MN15/LanL2DZ level was employed to study the structural analysis, electronic properties, visual studies, and sensor mechanisms of modified graphene systems for the detection of diisobutyl pththalate (DIBP). An increase in energy gap values was observed for all studied systems on complexation with gas molecules, which depicted the stable properties of the system. The electronic properties revealed that upon adsorption, the DIBP-Sn-N@GP energy gap was the smallest at 2.778 eV, which indicates great conductivity. The adsorption energy showed that chemisorption occurred in the studied systems. DIBP-Si-N@GP showed the strongest adsorption energy of -18.171 eV, while DIBP-N@GP showed weak chemisorption of -0.914 eV. According to the UV-visible spectrum, DIBP-Ge-N@GP has the greatest peak at a wavelength of 1979.79 nm in the first excited state, corresponding to the H-1→L+2 transition. The sensor mechanism showed that among the tested surfaces, DIBP-Si-N@GP showed the best sensing properties and can be considered good gas sensor materials, attributed to its highest adsorption energy, stabilization energy, and charge transfer values with the lowest back donation energy value.

Keywords: Adsorption; Codoped; DIBP; Graphene; Nitrogen-doped; Sensor.