Catalysis Today, Vol.147, No.2, 150-157, 2009
Comparison of H-2 production from ethanol and ethylene glycol on M/Pt(111) (M = Ni, Fe, Ti) bimetallic surfaces
The reactions of ethylene glycol and ethanol have been studied on Fe/Pt(1 1 1) and Ti/Pt(1 1 1) bimetallic surfaces utilizing temperature programmed desorption (TPD). These results are compared to our previous studies on Ni/Pt(1 1 1) to illustrate the trend in the reforming activity on 3d-Pt bimetallic surfaces. The oxygenates decomposed on these surfaces to produce mainly H-2 and CO. The bimetallic surfaces were prepared by thermal evaporation of Fe or Ti onto Pt(1 1 1), using Auger electron spectroscopy (AES) to monitor surface compositions. Surfaces prepared by deposition of a monolayer of Fe or Ti on Pt(1 1 1), designated Fe-Pt-Pt(1 1 1) or Ti-Pt-Pt(1 1 1), displayed higher reforming activity for both ethylene glycol and ethanol than the corresponding subsurface monolayer Pt-Fe-Pt(1 1 1) and Pt-Ti-Pt(1 1 1) structures or clean Pt(1 1 1). The reforming yield increased as the surface cl-band center, calculated from density functional theory (DFT), shifted closer to the Fermi level. The reforming selectivity of oxygenates, especially ethanol, began to decrease as the d-band center shifted closer to the Fermi level. Combining results in the current work with previous studies on Ni/Pt(1 1 1), a general criterion can be formulated for selecting 3d-Pt bimetallic surfaces with desirable reforming activity and selectivity. (C) 2008 Elsevier B.V. All rights reserved.
Keywords:Pt(111);Ni;Fe;Ti;Ethylene glycol;Ethanol;Bimetallic surface;TPD;H-2 production;d-Band center