Reactions of water and ethanol with polycrystalline TiC surfaces

Abstract

The adsorption and reaction of water and ethanol with polycrystalline TiC coatings have been investigated and compared with those of the nonpolar (100) face of single crystal TiC. This work is pursued to develop a fundamental understanding of the surface bonding and reaction properties, thus enabling the use of TiC as a tribological coating material. Temperature-programmed desorption has been used to characterize the desorption behavior of these model adsorbates as well as that of products resulting from their reaction with the TiC surface. Following adsorption at 100K, molecular desorption as well as desorption of reaction products is evident for both water and ethanol. Approximately 70% of the water in the monolayer is judged to irreversibly react with the TiC surface, producing a surface oxide and gaseous hydrogen and carbon monoxide. Approximately 92% of the ethanol in an adsorbed monolayer reacts, predominantly producing gaseous ethene. These results are similar to those on TiC(100) surfaces, although a greater extent of surface reactivity is observed on the polycrystalline surface.