A DFT study of ethanol adsorption and decomposition on α-Al₂O₃(0 0 0 1) surface

Graphical abstract: - Highlights: • Ethanol decomposition has been studied over α-Al₂O₃(0 0 0 1) surface. • EDD and DOS results confirm the stable adsorption of ethanol on the surface. • DFT calculations favor ethylene formation via C_β−H bond scission. • The formation of acetaldehyde has higher energy barrier. - Abstract: Ethanol adsorption and decomposition on the clean α-Al₂O₃(0 0 0 1) surface have been systematically investigated by density functional theory calculations. The nature of the surface-ethanol bonding has studied through the density of states (DOS) and the electron density difference (EDD) contour plots. The DOS patterns confirm that the lone pair electrons of EtOH are involved in the formation of a surface Al−O dative bond and the EDD plots provide evidences for the bond weakening/forming, which are consistent with the DOS analysis. Our ethanol decomposition results indicate that ethanol dehydration to ethylene (CH₃CH₂OH_(a) → C₂H_4(g) + OH_(a) + H_(a)), is the main reaction pathway with the energy barrier of 1.46 eV. Although the cleavage of the hydroxyl group of ethanol has lower energy barrier, the further decomposition of ethoxy owns much higher energy barrier.