Geometry and Electronic Properties of Glycerol Adsorbed on Bare and Transition-Metal Surface-Alloyed Au(111): A Density Functional Theory Study

Abstract

Glycerol exists in large amounts owing to its role as a byproduct in biodiesel production, and thanks to its chemical composition, it can be converted into more high-value products, such as mono- and polyethers, esters, diols, acrolein, and others. Hence, predicting glycerol-reactive properties is of utmost importance for designing efficient catalytic processes for its selective (electro)catalytic transformations; however, such an understanding is still far from complete. In this work, we performed quantum chemical calculations to validate a range of dispersion-corrected functionals to accurately predict and interpret structural, electronic, and vibrational properties of glycerol adsorbed on bare and transition-metal surface-alloyed Au(111) surface. optB86b-vdW (van der Waals) was found to have the overall best agreement with experiments concerning lattice constant, bulk stress, surface energy, and methanol adsorption among PBE (Perdew–Burke–Ernzerhof), optB88-vdW, optPBE-vdW, vdW-DF (density functional), vdW-DF2 (density functional 2nd version), and vdW-BEEF (Bayesian error estimation functional). Glycerol adsorption energy is found to correlate well with the calculated d-band center of the transition-metal-containing Au(111) surface layer. O–H stretching vibrations are found to be very sensitive of the surface-alloy atom and resulted in large shifts toward lower wavenumbers, when compared to those on bare Au(111). The latter results clearly show that adsorption of glycerol to surface-alloy atoms can be monitored in situ by infrared spectroscopy.