Photoemission spectroscopy investigation of the electronic structure of carbidic and graphitic carbon on Ni (111)

Photoemission measurements have been carried out on different forms of carbon deposits of catalytic importance on the (111) face of nickel, and give a picture of the electronic structure of “carbidic” and “graphitic” carbon. The photoemission spectra of graphitic overlayers strongly resemble spectra taken on graphite bulk samples but show an (almost) rigid shift of the levels with respect to the Fermi level. The results we obtain for carbidic carbon can be understood on the basis of recent surface electronic structure calculations. In particular a p-like state has been observed very near the Fermi level, which is probably responsible for the high chemical reactivity of carbidic carbon