Adsorption of hazardous gases on poly(3,4‐ethylenedioxythiophene): Density functional theory study

Abstract

AbstractWe have studied the adsorption of different hazardous gases (such as SO3, NH3, NO2, and H2S) on poly(3,4‐ethylenedioxythiophene) (PEDOT) to manifest it as a gas sensor using density functional theory (DFT). Both chemisorption and physisorption channels have been investigated to reveal the interaction pathway between PEDOT and hazardous gases. PEDOT can interact with SO3, NH3, NO2, and H2S via a physisorption channel with corresponding adsorption energies −13.32, −6.88, −6.02, and −7.47 kcal/mol, respectively. The chemisorptive nature has been observed only for SO3. But this pathway is kinetically and thermodynamically less accessible compared to the physisorption channel. The large adsorption energy value for SO3 (−13.32 kcal/mol) shows the better sensitivity of PEDOT towards SO3 compared to the rest three gases. The electronic properties of PEDOT vary based on its interaction with different gases. The frontier molecular orbitals, band gap, natural bond orbital charge, UV–vis spectra, and conductivity studies support the fact. The external electric field has been applied as a technique to tune the recovery time for SO3.