TY - GEN A1 - Boehn, Bernhard von A1 - Penschke, Christopher A1 - Li, Xiaoke A1 - Paier, Joachim A1 - Sauer, Joachim A1 - Krisponeit, Jon-Olaf A1 - Flege, Jan Ingo A1 - Falta, Jens A1 - Marchetto, Helder A1 - Franz, Torsten A1 - Lilienkamp, Gerhard A1 - Imbihl, Ronald T1 - Reaction dynamics of metal/oxide catalysts: Methanol oxidation at vanadium oxide films on Rh(111) from UHV to 10-2 mbar T2 - Journal of Catalysis N2 - Recent advances in in situ microscopy allow to follow the reaction dynamics during a catalytic surface reaction from ultra-high vacuum to 0.1 mbar, thus bridging a large part of the pressure gap. Submonolayer vanadium oxide films on Rh(111) have been studied during catalytic methanol oxidation in situ with spatially resolving imaging techniques. At 10-6 to 10-4 mbar VOx condenses into macroscopic circular islands that exhibit a substructure, consisting of a reduced island core and an oxidized outer ring. This substructure arises due to an oxygen gradient inside the VOx islands, which results in different coexisting 2D-phases of VOx on Rh(111). This substructure is also responsible for a "breathing-like" oscillatory expansion and contraction that the islands undergo under stationary conditions. Using density functional theory, the 2D-phase diagram of VOx on Rh(111) has been computed. The oscillatory behavior can be understood as a periodic phase transition between two 2D phases of VOx. With a newly developed near ambient pressure – low-energy electron microscope, it was shown that VOx islands disintegrate at 10-2 mbar, resulting in turbulent dynamics. KW - Vanadium oxide KW - Methanol oxidation KW - Inverse catalyst KW - Restructuring KW - Near ambient pressure low-energy electron microscope KW - Heterogeneous catalysis KW - Pressure gap Y1 - 2020 U6 - https://doi.org/10.1016/j.jcat.2020.03.016 SN - 0021-9517 SN - 1090-2694 VL - 385 SP - 255 EP - 264 ER -