AVS 47th International Symposium
    Surface Science Tuesday Sessions
       Session SS1-TuA

Paper SS1-TuA6
Selective Surface Reactions of Single Crystal Metal Carbides: Alkene Production from Short Chain Alcohols on Titanium Carbide and Vanadium Carbide

Tuesday, October 3, 2000, 3:40 pm, Room 208

Session: Mechanisms and Control of Surface Reactions
Presenter: R.L. Guenard, University of Houston
Authors: R.L. Guenard, University of Houston
L.C. Fernández-Torres, University of Houston
S.S. Perry, University of Houston
P. Fantz, The Aerospace Corporation
S.V. Didziulis, The Aerospace Corporation
Correspondent: Click to Email
The reaction of short chain alcohols on the (100) surface of single crystal vanadium carbide (VC) and titanium carbide (TiC) have been studied using temperature programmed desorption (TPD), high resolution electron energy loss spectroscopy (HREELS), and x-ray photoelectron spectroscopy (XPS). The short chain alcohols form an alkoxide upon adsorption at 153K on both VC(100) and TiC(100). The alkoxide intermediate selectively reacts with the carbides to produce an alkene and water. Specific isotopic labeling revealed @gamma@ C-H bond scission as a key step in alkene formation. A comparison of the TPD intensities of reaction products on both surfaces indicates that VC(100) has a higher reactivity towards alcohols, with an approximately four-fold higher reaction yield as compared to TiC(100). This difference in reactivity is accounted for by a difference in the electronic structure of these carbide surfaces. This study implicates potential pathways of lubricant degradation in tribological applications and highlights the possible need for passivating additives for carbides used in such applications.