(292e) Combined DFT and Microkinetic Modeling Study of Ethanol Steam Reforming On Close-Packed Transition Metals

The catalytic conversion of biomass to fuels and chemicals
is an increasingly important research topic. Ethanol, produced from
fermentation of biomass, has been considered as a source of hydrogen for fuel
cells via steam reforming. Ethanol steam reforming has been carried out over
Co, Ni, Pt, Rh, and Ru based catalysts, among others, and on a variety of
supports.[1]

It is expected that the nature of the transition metal
catalyst will play a key role in the selectivity and activity of the steam
reforming process. In order to better understand the role of the metal in this
process, a combined density functional theory and microkinetic modeling study
was performed. DFT calculations were performed for the close-packed facets of
Co, Ni, Pt, Rh, and Ru to identify possible key steps in the mechanism. The
impact of these steps on the overall rate is then investigated via detailed
microkinetic modeling. We find that the early dehydrogenation steps tend to be
rate controlling, while later C‑C and C‑O cracking steps control
the selectivity to C₁ and C₂ hydrocarbons, respectively. In
general agreement with the literature, Pt is predicted to be most selective to
C-C cracking, while Ru is predicted to show the highest selectivity to C‑O
cleavage.

1.            Bion, N., D. Duprez, and F. Epron, Design of
Nanocatalysts for Green Hydrogen Production from Bioethanol. ChemSusChem,
2012. 5(1): p. 76-84.