Electronic properties of the clean and hydrogen-covered TiC(111) Ti-terminated polar surface

A polar TiC(111)-Ti(1 × 1) surface has been prepared by ion bombardment and annealing of TiC(111). The hexagonal array of exposed titanium atoms gives rise to surface properties similar to those of metallic Ti(0001). Angle-resolved photoemission spectra indicate a strong titanium-derived surface state just below EF at Γ, which is rapidly quenched by hydrogen adsorption. As on Ti(0001), hydrogen is found to chemisorb readily, resulting in a (1 × 1) overlayer and a hydrogen 1s-induced level at 6.8 eV below EF at Γ with a ∼1 eV dispersion width. These results have important implications for the use of refractory metal compounds in catalysis and electrocatalysis. © 1981.