Adsorption/desorption process of formaldehyde onto iron doped graphene: a theoretical exploration from density functional theory calculations

Abstract

The interaction of formaldehyde (H₂CO) onto Fe-doped graphene (FeG) was studied in detail from density functional theory calculations and electronic structure analyses. Our aim was to obtain insights into the adsorption, desorption and sensing properties of FeG towards H₂CO, a hazardous organic compound. The adsorption of H₂CO was shown to be energetically stable onto FeG, with adsorption energies of up to 1.45 eV and favored in different conformations. This interaction was determined to be mostly electrostatic in nature, where the oxygen plays an important role in this contribution; besides, our quantum molecular dynamics results showed the high stability of the FeG–H₂CO interaction at ambient temperature (300 K). All the interactions were determined to be accompanied by an increase in the HOMO–LUMO energy gap with respect to the isolated adsorbent, indicating that FeG is highly sensitive to H₂CO with respect to pristine graphene. Finally, it was found that external electric fields of 0.04–0.05 a.u. were able to induce the pollutant desorption from the adsorbent, allowing the adsorbent reactivation for repetitive applications. These results indicate that FeG could be a promising candidate for adsorption/sensing platforms of H₂CO.