Understanding 2-Propanol Sensing Mechanism of Pd Modified Graphene Based Gas Sensor Devices using DFT Study

Abstract

The present report investigates Pd-modified/Pd-doped graphene (Pd-G) nanosheet as a gas sensing element for the detection of 2-propanol or Isopropyl alcohol (IPA) molecule via studying different adsorption characteristics of the same using density functional theory (DFT) employing QuantumATK Toolkit (v.2019). Two different structures were considered here viz. optimized configuration with dangling bonds (Case-I) and optimized configuration without dangling bonds (Case-II). Various essential electronic properties were computed and discussed here in detail for a clear understanding of the atomic level interaction between IPA and Pd-G such as band structure, density of states (DOS), crucial gas adsorption parameters, electron density difference (EDD) and electron localization function (ELF). Band structure and DOS showed that the configurations were semi-metallic in nature. The electron-donating characteristics of IPA towards the substrate (i.e. PdG) were observed from Mulliken charge transfer and EDD. To study the electron localization across the molecular and/or atomic structure, ELF mapping was also performed. Moreover, the gas sensing parameters inferred that at low (room) temperature, Pd-doped graphene can be used as a potential gas sensor device for the sensing of 2-propanol molecules.