Adsorption and reaction of thiophene on α-Mo2C(0 0 0 1)

Thiophene adsorbs reversibly and irreversibly on α-Mo2C(0 0 0 1). Irreversible thiophene adsorption results in decomposition to surface C, surface S, and gaseous dihydrogen. The chemical states of the carbon and sulfur as identified by X-ray photoelectron spectroscopy are carbidic and sulfidic, respectively, implying that the surface decomposition products are bound to metal sites. The H2 is evolved in two features during thermal desorption spectroscopy experiments, a low temperature desorption-limited peak and a high temperature reaction-limited peak. The reaction-limited peak is likely due to the decomposition of a surface hydrocarbon species that results from thiophene decomposition. Photoemission results indicate that C–S bond scission occurs by 170 K and possibly as low as 105 K.