(289g) 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.