To carburize the clean tungsten surface, 1.0x10 -4 Torr ethylene was decomposed using a hot filament sputter gun with 0.5 kV bias potential for 10 min. The surface was then annealed to > 1000 K to form a carbide film. Both XPS and AES measurements of the surface atomic ratio revealed a characteristic carbidic carbon feature and an atomic C/W ratio between 1.0 and 1.1 using standard sensitivity factors with no detectable impurities.

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In the current paper we will provide a review of our recent efforts in experimental studies of tungsten carbides as alternative electrocatalysts for methanol electro-oxidation. We will first discuss ultrahigh vacuum (UHV) studies on single crystal surfaces to demonstrate the feasibility of using tungsten carbides for methanol decomposition. We then discuss UHV studies on polycrystalline thin films and foils to approximate commercially relevant catalysts, thus bridging the “materials gap” and demonstrating that the fundamental chemistry observed in UHV over single crystal surfaces is applicable to morphologically complex surfaces. Electrochemical studies of thin films will be discussed to bridge the “pressure gap” and to verify that tungsten carbides are both active and stable in an electrochemical environment. Finally, we will provide performance data from direct methanol fuel cell (DMFC) testing that incorporates tungsten carbides as the anode electrocatalysts.

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