Theoretical Study of the Adsorption/Dissociation Reactions of Formic Acid on the α-Al₂O₃(0001) Surface

Formic acid was used as the model of lauric acid to investigate the microscopic mechanism of the anti-icing behavior and was checked to find out if it can be catalyzed to produce H 2 for fuel cells by the α-Al 2 O 3 (0001) 2 × 2 supercell slab model. The density functional theory with the all-electron double numerical polarized basis sets was employed. The results show that when it involves the carboxyl O and hydroxyl H atom the 1,2-dissociated adsorbate is the most stable intermediate on the dry Al 2 O 3 (0001) surface and is energetic barrier free to form the fairly stable ROCO- and HO-covered surface with the binding energy of 59.5 kcal/mol, and this dissociation mode has the lowest energy barrier of 14.9 kcal/mol to form the HOCO- and H 2 O-covered surface after the surface is fully hydroxylated. The energetic barrier of the HCOOH dehydrogenation and dehydration reactions on the alumina surface decreased considerably from 65.3 to 30.6 kcal/mol and from 62.1 to 26.8 kcal/mol, respectively, in comparison with the gaseous decomposition. The dissociated configuration of lauric acid was tested, and it was found that it dissociated with free energy barrier through 1,2-hydrogen migration into the C 11 H 23 OCO- and HO-covered surface with a binding energy of 60.7 kcal/mol. The present theoretical work is useful to gain some new insights on the microscopic interaction mechanism of the superhydrophobic alumina surface fabrication procedure and on the heterogeneous catalysis reactions of the H 2 production.