From dull to shiny: A novel setup for reflectance difference analysis under catalytic conditions.

We have developed an experimental setup for optically monitoring a catalytically active surface under reaction conditions. A flow reactor with optical access allows us to image the behavior of an active catalyst surface down to the millimeter length scale. We use reflectance difference measurements with 625 nm light to investigate CO oxidation on Pd(100) at 300 mbar and 320 °C. We conclude that the changes in visible contrast result from the formation of an oxide layer after surface oxidation.