Spectroscopic and scanning probe studies of oxygen and water on metal carbide surfaces

Spectroscopic and scanning probe techniques were applied to the study of clean, (100) single-crystal surfaces of titanium carbide (TiC) and vanadium carbide (VC), and their interactions with oxygen and water. We find that oxygen adsorbs dissociatively on both surfaces, but discriminates between them by reacting with TiC to form an oxide while forming a metastable overlayer on VC. Water bonds molecularly and dissociatively at low temperatures and behaves similarly on both materials. These results are interpreted in the context of surface electronic structure.