Glycerol adsorption on a defected Pt₆/Pt(100) substrate: a density functional theory investigation within the D3 van der Waals correction

We report an ab initio investigation based on density functional theory calculations within the van der Waals (vdW) correction to obtain an improved atomistic understanding of the adsorption properties of glycerol on a defected Pt₆/Pt(100) substrate, which includes low-coordinated Pt sites and well defined Pt(100) terraces. We found that in the lowest energy structure glycerol weakly adsorbs on a low-coordinated cationic Pt site via one of the anionic O atoms with the central carbonate chain orientated nearly parallel to the surface plane. As expected, the vdW correction enhances the adsorption energy, however, while it does not change the adsorption site preference, it affects the orientation of the CCC frame with respect to the substrate. Our results of the work function and Bader charges suggest a negligible charge transfer between glycerol and the Pt₆/Pt(100) substrate, which can be attributed mostly to polarizations between the atoms of the molecule and of the surface.