Pattern Formation in Catalytic H2 Oxidation on Rh: Zooming in by Correlative Microscopy

Spatio-temporal nonuniformities in H-2 oxidation on individual Rh(h k l) domains of a polycrystalline Rh foil were studied in the 10(-6) mbar pressure range by photoemission electron microscopy (PEEM), X-ray photoemission electron microscopy (XPEEM), and low-energy electron microscopy (LEEM). The latter two were used for in situ correlative microscopy to zoom in with significantly higher lateral resolution, allowing detection of an unusual island-mediated oxygen front propagation during kinetic transitions. The origin of the island-mediated front propagation was rationalized by model calculations based on a hybrid approach of microkinetic modeling and Monte Carlo simulations.

Automated summary

In this study, spatial-temporal nonuniformities in H-2 oxidation on individual Rh(hkl) domains of a polycrystalline Rh foil were investigated using PEEM, XPEEM, and LEEM. The latter two techniques were used for in situ correlative microscopy, which provided higher lateral resolution and enabled the detection of island-mediated oxygen front propagation during kinetic transitions. The origin of this phenomenon was rationalized through model calculations based on a hybrid approach of microkinetic modeling and Monte Carlo simulations.