DFT study of ethanol and formic acid adsorption on CaO(001)

V. ORAZI ; P. BECHTHOLD; E. A. GONZÁLEZ; A. JUAN; J. M. MARCHETTI; P. V. JASEN

Workshop; IX Workshop on Novel Methods for Electronic Structure Calculations; 2021

Ethanol and formic adsorption on CaO (0 0 1) surface at low coverage is studied using DensityFunctional Theory (DFT) calculations with van der Waals corrections. We investigated the CaOsurface in its rock salt structure. The more favorable sites for C2H5OH adsorption are on one (ortwo) Ca cations bonding the O atom from ethanol. H form (OH group) bond to surface oxygenswith an adsorption energy of -1.12 (-1.14) eV. The distance of ethanol to surface is in the range of2.3 - 2.5 ̊A. The molecule presents a strong elongation of the adsorbed O-H group being 53% (51%)larger that its molecular distance. Bond order analysis shows that distances and BO are similar forCa-O molecule and Ca-O surface. A charge transfer occurs from O atom of the 2nd layer to Ca ionsat 1st layer and the molecular O atom gain some charge, while H loses charge towards surface oxygenand from this to the rest of the surface. In the case of H-COOH we found two possible adsorptionsites with -2.38 and -2.07 eV, again the O-H bond is elongated with respect to the molecular states.DOS and bonding analysis are performed in both cases.