Adsorption characteristics of Fe-doped graphitic carbon nitride/PEDOT polymer hybrid material as sensors for dissolved gases in the transformer oil: A DFT study

Abstract

This study evaluates the adsorption potency of a hybrid nanomaterial composed of Fe-doped graphitic carbon nitride-poly (3,4 -ethylenedioxythiophene) (Fe@C3N4-PEDOT) towards acetylene (C2H2), methane (CH4), and hydrogen (H2) gases. Density functional theory (DFT) was employed to optimize the structures and to evaluate or examine the electronic properties, adsorption, and interaction behaviour. Adsorption energies (Eads) for C2H2 (-0.871 eV), H2 (-0.381 eV), and CH4 (-0.381 eV) specify exothermic and spontaneous interactions. C2H2 (-0.871 eV) shows moderate chemisorption, while CH4 and H2 (-0.381 eV each) show weak chemisorption, within the reusable sensor range. The C2H2 showed greater interaction, reducing the energy gap to 2.256 eV, thereby improving conductivity and reactivity. Density of States (DOS) was equally confirmed, as it reveals a significant orbital overlap between the gas and the studied material. Natural Bond Orbital (NBO) analysis also showed a good donor-acceptor interaction with high stabilization energy, which affirms chemisorption. The hybrid nanomaterial’s interaction with these gases, especially acetylene, suggests its high suitability for selective detection and adsorption of hazardous gases in oil and oil-polluted environments. In all, Fe@C3N4-PEDOT shows promising potential as a sensor material with high sensitivity and environmental importance.