Towards cleaner indoor air: Analyzing the effects of molecule chemistry and steric constraints on the chemisorption of formaldehyde and its derivatives on functionalized graphene surfaces

Interactions of selected volatile organic compounds namely formaldehyde, acrolein, acetaldehyde, and acetone with functionalized graphene surfaces were theoretically investigated. The focus was on the effects of oxygen and nitrogen containing groups on the energy barriers during the chemisorption processes. Acrolein and acetone exhibit the highest stabilization energies during the physisorption due to enhanced dispersion-type interactions. The phenolic OH groups were found as the most prone to interact with carbonyl oxygen of the target compounds resulting in the subsequent covalent bond formation. The energy barriers for the chemisorption are lower than 10 kcal mol⁻¹ for all molecules considered, indicating that their chemisorption from the vapor-phase readily occurs at room temperature. Simultaneously, the energy barriers for the desorption are above 20 kcal mol⁻¹ for all molecules, indicating that desorption at room temperature is not possible. NH-type moieties were found to be less advantageous although their presence frequently leads to chemisorption. The efficiency of the chemisorption was found to be dependent on steric constraints and on the charge on the carbonyl carbon atom. The electron withdrawing moieties of formaldehyde derivatives were found as negatively affecting a bond formation efficiency. The theoretical findings were supported by those found in experimental approaches.