title: The electronic factor in alkane oxidation catalysis.
abstract: This article addresses the fundamental question of whether concepts from semiconductor physics can be applied to describe the working mode of heterogeneous oxidation catalysts and whether they can be even used to discriminate between selective and unselective reaction pathways. Near-ambient-pressure X-ray photoelectron spectroscopy was applied to the oxidation of n-butane to maleic anhydride on the highly selective catalyst vanadyl pyrophosphate and the moderately selective MoVTeNbO(x) M1 phase. The catalysts were found to act like semiconducting gas sensors with a dynamic charge transfer between the bulk and the surface, as indicated by the gas-phase-dependent response of the work function, electron affinity, and the surface potential barrier. In contrast, only a minor influence of the gas phase on the semiconducting properties and hence no dynamic surface potential barrier was monitored for the total oxidation catalyst V2O5. The surface potential barrier is hence suggested as descriptor for selective catalysts.
authors: Department of Inorganic Chemistry, Fritz-Haber-Institut der Max-Planck-Gesellschaft, Faradayweg 4-6, 14195 Berlin (Germany); BasCat, UniCat BASF JointLab, TU Berlin, Marchstrasse 6, 10587 Berlin (Germany). me@fhi-berlin.mpg.de.
authors: Maik
authors: M
authors: Eichelbaum
authors: Michael
authors: M
authors: Hävecker
authors: Christian
authors: C
authors: Heine
authors: Anna Maria
authors: AM
authors: Wernbacher
authors: Frank
authors: F
authors: Rosowski
authors: Annette
authors: A
authors: Trunschke
authors: Robert
authors: R
authors: Schlögl
keywords: heterogeneous catalysis; n-butane; selective oxidation; semiconductors