Deoxygenation of Biomass-Derived Oxygenates: Reaction of Furfural on Zn-Modified Pt(111)

Temperature-programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS) were used to characterize the adsorption and reaction of furfural on Pt(111) and Zn-modified Pt(111) surfaces. Furfural was found to bond to Pt(111) via the aromatic ring, which facilitated C-C bond scission and ring opening at low temperatures, leading to unselective decomposition to CO and H-2. In contrast, on Zn-modified Pt(111), furfural bonds via the aldehyde carbonyl in an eta(2)(C,O) configuration with the aromatic furan ring tilted away from the surface. This bonding configuration weakens the C-O bond in the carbonyl, which undergoes scission upon heating above 250 K to form a stable (C4H3O)-CH = intermediate. These results provide useful mechanistic insights for the hydrodeoxygenation of furfural on PtZn catalysts.