AVS 59th Annual International Symposium and Exhibition
    Surface Science Tuesday Sessions
       Session SS-TuP

Paper SS-TuP25
Synthesis, Characterization and Catalytic Activity of Pt Nanoparticles Supported on γ-Al2O3 and WC: Size and Support Effects

Tuesday, October 30, 2012, 6:00 pm, Room Central Hall

Session: Surface Science Poster Session
Presenter: M. Ahmadi, University of Central Florida
Authors: M. Ahmadi, University of Central Florida
L. Merte, University of Central Florida
B. Roldan Cuenya, University of Central Florida
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Direct-methanol fuel cells (DMFC) are one of the promising candidates for alternative clean energy generation. Extensive efforts are going on to improve the efficiency of these cells using different Pt-based catalyst. Although tungsten carbide (WC) shows similar electronic structure as Pt and has promising catalytic properties, it is not extensively used due to its instability. However, it has been observed that one monolayer of Pt on the surface of WC displays a similar performance as bulk Pt and furthermore, it stabilizes the WC, which makes it a very cost-effective alternative for Pt electrodes. In this work we have synthesized size- and shape-selected Pt nanoparticles (NPs) via inverse micelle encapsulation methods. The NPs were then supported on WC and γ-Al2O3 nanocrystalline powders as well as on WC/W thin films. We have investigated the size and morphology of our NPs by atomic force microscopy (AFM) and by transmission electron microscopy (TEM) and their chemical composition by X-ray photoelectron spectroscopy (XPS). Methanol oxidation was carried out in a packed-bed mass flow reactor and mass spectrometry was employed to quantify the catalyst’s activity as a function of the NP size. The evolution of the structure of the Pt NPs during the oxidation of methanol was investigated under operando conditions using extended X-ray absorption fine-structure spectroscopy (EXAFS).