Similarities in the decomposition and dehydrogenation of cyclohexene on (4x4)-C/Mo(110) and Pt(111)

The decomposition and dehydrogenation of cyclohexene have been used as probing reactions to directly compare the surface reactivities of carbon-modified Mo(110) and Pt(111). By using temperature programmed desorption (TPD) and high-resolution electron energy loss spectroscopy (HREELS), we find that the dominant decomposition pathway of cyclohexene can be converted from complete decomposition to atomic carbon and hydrogen on clean Mo(110) to partial dehydrogenation to benzene and hydrogen on (4 x 4)-C/Mo(110). The latter reaction mechanism is very similar to that observed on Pt(111). Furthermore, in contrast to the near identical catalytic properties that are commonly observed for bulk molybdenum carbide and nitride powder materials, we find that the reactivities of carbon-modified and nitrogen-modified Mo(110) surfaces are qualitatively different.