Potential application of tungsten carbides as electrocatalysts. 1. Decomposition of methanol over carbide-modified W(111)

The decomposition of methanol over clean and carbide-modified W(111) is studied by using temperature-programmed desorption (TPD), high-resolution electron energy loss spectroscopy (HREELS), and Auger electron spectroscopy (AES). The chemistry of methanol on unmodified W(111) is predominantly complete decomposition to produce atomic carbon and H-2, with slightly less than 15% of the adsorbed methanol dissociating to form CO, CH4, and H-2. Once the W(111) surface is carbide-modified, however, the most dominant reaction pathway is still the complete decomposition of CH3OH at similar to 55%, but with significantly more CO and CH4 desorbing as gas-phase products. If the carbide surface is further modified with oxygen, the activity toward the production of CO is further enhanced and becomes the dominant pathway, while the yield of gas-phase CH4 is slighted reduced compared to the unmodified C/W(111) surface. These results will be compared to the activity of Pt group metal surfaces to explore the potential application of using tungsten carbides as an alternative to Pt group metal electrodes in fuel cells.