A van der Waals density functional study of the adsorption of ethanol on the α-alumina (0001) surface

Modelling the strength of mineral–organic binding: organic molecules on the α-Al2O3(0001) surface

“…3(a)) was slightly more strongly bound, with the adsorption energy of −1.63 eV and the much shorter Al–O chemisorption bond length of 1.71 Å; the dissociated hydrogen was bound to a nearby surface oxygen with the O–H distance of 0.98 Å. This adsorption behaviour is similar to that of water, where dissociative adsorption was also energetically favourable, and is in agreement with the previous theoretical study of ethanol on α-Al 2 O 3 (0001) 51 which found dissociative adsorption to be ∼0.1 eV more stable than molecular adsorption. It is also consistent with the Mulliken charges of the α-Al 2 O 3 -methanol system (Table S3†), which suggest primarily covalent bonding in the molecular configuration and partly ionic bonding in the dissociative configuration, and with PDOS data (Fig.…”

“…57 Ethanol was shown to bind slightly more strongly to the a-Al 2 O 3 (0001) surface in a dissociative conguration than in a molecular conguration. 51 For phenols, methanol and methylamine, only non-dissociative adsorption congurations have been considered. 50,52,56 A study of formic acid adsorption and dissociation found the 1,2-dissociated structure where the carboxyl oxygen and hydroxyl hydrogen atoms of formic acid were adsorbed, involving hydrogen bonding of the dissociated hydroxyl group, to be the most stable.…”

“…There have been far fewer studies of adsorption of organic molecules onto α-Al 2 O 3 , which typically considered adsorption of one molecule or one class of molecules, e.g. methanol and ethanol, 50,51 phenols, 52 carboxylic acids, 53–55 amines 56 and nitro compounds. 57 Ethanol was shown to bind slightly more strongly to the α-Al 2 O 3 (0001) surface in a dissociative configuration than in a molecular configuration.…”

Revealing the influence of Cyano in Anchoring Groups of Organic Dyes on Adsorption Stability and Photovoltaic Properties for Dye-Sensitized Solar Cells

“…The vacuum gap of 40 Å is used to avoid the interaction of dyes with the adjacent slab. It has confirmed in earlier studies that the inclusion of van der Waals (vdW) functional along with GGA improved the energies of adsorbed molecules on the oxide surfaces 70 , 71 . Hence, we used optB86b-vdW 72 , 73 functional to treat the long-range interactions of the studied system.…”

Adsorption of organic molecules at the TiO2(110) surface: The effect of van der Waals interactions

“…Sorescu et al investigated the adsorption of CO 2 on TiO 2 (110) and found that adsorption was predicted to be stronger when calculated with several dispersion-corrected functionals as compared with GGA calculations, bringing the theoretical results into closer agreement with experiment [26]. In another recent work by Johnston [27] various vdW functionals were employed to calculate the adsorption energy and geometries of ethanol at the α-Al 2 O 3 (0001) surface. This study also found that vdW functionals predicted stronger adsorption than the GGA functional, although both methods predicted dissociative adsorption (with transfer of a proton to the surface) to be more stable than molecular adsorption.…”