Institution: | aCenter for Atomic-scale Materials Physics, Department of Physics, Building 307, Technical University of Denmark, 2800 Lyngby, Denmark bInterdisciplinary Research Center for Catalysis (ICAT), Department of Physics and Department of Chemical Engineering, Building 312, Technical University of Denmark, 2800 Lyngby, Denmark |
Abstract: | We have, theoretically and experimentally, investigated the dissociation of methane on the terraces and steps of a Ni(1 1 1) surface. Using Density Functional Theory (DFT) total energy calculations combined with Ultra High Vacuum (UHV) experiments, we find that the steps exhibit a higher activity than the terraces. We have, furthermore, investigated how carbon and sulfur present on the surface will deactivate the steps, leaving only the terraces active. We find the intrinsic sticking probabilities of methane on the steps and terraces at 500 K to be 2.8 × 10−7 for the steps and 2.1 × 10−9 for the terraces, in complete agreement with our calculated difference in activation energy of 17 kJ/mol. |