DFT + Vdw-DF Calculations for the Energetics of Furfural Hydrogenation On Cu(111) and Pd(111)

DFT + D Calculations for the Energetics of Furfural Hydrogenation on Cu(111) and Pd(111)

Bin Liu^$, Lei Cheng^¢, Larry Curtiss^¢ and Jeffrey Greeley^£*

^$Department of Chemical Engineering, Kansas State University, Manhattan, KS 66506, ^¢MSD, Argonne National Laboratory, Argonne, IL 60439, ^£School of Chemical Engineering, Purdue University, West Lafayette, IN 47907-2100

ABSTRACT

<>There is a widespread presence of the hydrogenation of unsaturated aldehyde compounds, which are commonly derived from lignocellulosic sources, in hydrotreating of bio-oil, or catalytic transformations to obtain commodity chemicals. It is highly valuable to have a reliable way to obtain the fundamental thermodynamics and kinetics for the purpose of catalyst design and process optimization to achieve higher chemical and energy efficiency.

<>It is a common and viable approach to employ model compounds to simplify the analysis and understand the chemistry, where density functional theory (DFT) calculations are extremely effective to obtain a first-hand information for a given reaction system. Nevertheless, a number of studies have noted that the dispersion effects due to van der Waals interactions can be a significant factor in determining the structural configurations and the accompanying energetics, and thus the catalytic trends in activities and selectivities in hydrogenation. Motivated by this consideration, we set out to perform a comparative DFT study on furfural hydrogenation into furfuryl alcohol, a valuable hydrogenation product, on close-packed Pd and Cu surfaces, using such functional as PW91, PBE, the DFT-D2 method of Grimme, and the vdW-DF functionals of Langreth and Lundqvist (in VASP 5) to investigate the dispersion ('D') effects on the hydrogenation thermodynamics and kinetics. This study chose Pd and Cu on the ground that they show very different selectivities in the final hydrogenation products. Using DFT+D method, we tried to address how the 'D' corrections affect surface absorptions in weak and strong binding scenarios. Built on this information, we developed a Brznsted-Evans-Polanyi (BEP) relationship to investigate how the dispersion corrections will affect the kinetics. This computational effort will complement the existing first-principles studies that aim to provide alternative solutions to current energy issues by revealing new computational insights in furfural hydrogenation chemistry and improving our capability of calculating the thermodynamic and kinetic properties of surface reactions.