Computational Study of the Dissociation Reactions of Methyl Acrylate on the Cu(111) Surface

Periodic density functional theory (DFT) calculations were performed to study the adsorption and dissociation of methyl acrylate (MA), with chemical formula CH2CHCOOCH3, on the Cu(111) surface. MA is a biodiesel surrogate molecule whose dissociation products may contribute to the corrosion of metallic components and engine damage. Three adsorption configurations were examined, the most stable of which is when the vinyl group (CH2═CH) covalently bonds with the Cu(111) surface with an adsorption energy of −1.38 eV and a charge transfer of −0.41|e|. The calculated reaction energies and activation barriers differ significantly from those in the gas phase, highlighting the influence of the Cu(111) surface on the reactivity. Climbing-image nudged elastic band (CI-NEB) calculations gave activation barriers between 38 and 82 kcal/mol with CH2CHCOOCH3 → CH2CHCO + OCH3 as the most favorable dissociation pathway. The reaction energies fall in the range −3 to 47 kcal/mol. Further insight into the adsorption and dissociation processes via the analysis of bond lengths, charge-transfer, and partial density of states indicates that two of the adsorption configurations are characterized by strong covalent interactions whereas the third configuration has a weaker interaction with the surface. These strong interactions with the surface weaken the C═C double bond and stabilize transition states providing a catalytic effect on the different dissociation processes. Our results demonstrate that the Cu(111) surface promotes strong adsorption that lowers the reaction energies and drastically modifies the dissociation mechanisms compared with those in the gas phase, thus shedding light on the possible corrosion effects of biodiesel on copper-containing components in automotive fuel systems and engines.