Monday, 25 June 2007 - 3:00 PM
Pencader 215
57

Reforming of Oxygenates for H2 Production on Bimetallic Surfaces

Orest Skoplyak, Mark A. Barteau, and Jingguang G. Chen. University of Delaware, Newark, DE

Production of hydrogen for use in fuel cells can be achieved by selective reforming of oxygenates. The oxygenates may be derived from renewable biomass and offer advantages such as low toxicity, low reactivity and compatibility with the current infrastructure for transportation and storage. In this study, the reactions of oxygenates, such as methanol, ethanol and ethylene glycol, were investigated on 3d-Pt(111) bimetallic surfaces using temperature-programmed desorption (TPD), high-resolution electron energy loss spectroscopy (HREELS), and Density Functional Theory calculations (DFT). The bimetallic surfaces were prepared by physical vapor deposition (PVD) of the desired second metal onto Pt(111), using Auger electron spectroscopy (AES) to monitor surface compositions. Oxygenates reacted on 3d-Pt(111) to primarily form H2 and CO. Surfaces prepared by deposition of a monolayer of Ni on Pt(111) at 300 K, designated as Ni-Pt-Pt(111), displayed increased reforming activity compared to Pt(111), subsurface monolayer Pt-Ni-Pt(111), and thick Ni/Pt(111). The experimentally measured reforming yield displayed a linear trend with the surface d-band center for both ethylene glycol and ethanol. The reforming activity increased as the surface d-band center moved closer to the Fermi level, opposite to the trend previously observed for hydrogenation reactions. DFT results indicated that the binding energy of methanol and ethanol increased as the d-band center of the bimetallic surface shifted closer to the Fermi level, which could be achieved by choosing 3d metals from the left side of the periodic table as the surface monolayer. Further studies are underway to investigate oxygenate reforming on other 3d-Pt-Pt(111) bimetallic surfaces.