The adsorption of ethyl formate on CaO: A DFT study

Abstract

Ethyl formate adsorption on CaO (001) is analyzed using Density Functional Theory (DFT) with Van der Waals corrections, implemented through the Vienna ab Initio Simulation Package (VASP). Our calculations reveals a possible adsorption site at low coverage with adsorption energy of -1.21 eV, which is more stable than ethanol and less stable than formic acid. Both molecular oxygens bond to two Ca atoms and the C methyl bonds to a surface oxygen. The analysis of the electronic structure and bonding show a stabilization of ethyl formate as a result of a shift in its states to lower energies, with respect to the gas phase. A relaxed molecular geometry is obtained after adsorption with no dissociation detected. There is a charge transfer (0.20 e) from the adsorbate to the surface. At the same time, Hsingle bondC (formate) experiences a charge decrease of 0.16 e. The Casingle bondO in the surface mostly shows a decrease in bond order after adsorption.