Time-of-flight studies on catalytic model reactions

摘要

Time-of-flight spectroscopy(TOF)and REMPI-TOF(resonance enhanced multi-photon ionization-TOF)were applied to measure the angular and translational energy distribution,as well as the internal state resolved energy distribution of desorption and reaction products on some model systems.Desorption of hydrogen and deuterium from clean and modified Pd(111)surfaces was studied,where the palladium sample was part of a permeation source.Water formation by reaction of oxygen with hydrogen on palladium was investigated by using different types of hydrogen supply:molecular H2 exposure and atomic H exposure from the gas phase,as well as H exposure by permeating hydrogen.Vanadium oxide nanostructures on Pd(111)were prepared and the influence on D_2 desorption and D2O production was investigated with the permeation technique.Additionally,deuterium desorption from sulfur and oxygen covered V(111)and V(100)surfaces was studied by TOF and REMPI-TOF spectroscopy.From the TOF spectra information concerning the reaction and desorption dynamics(activation barriers)could be gained.