Selective oxidation of propene at cesium and cesium-modified Ag(100) surfaces

The oxidation of propene at Ag(100), Ag(100)-Cs, and Cs surfaces has been i nvestigated by X-ray photoelectron spectroscopy in the temperature range 80 -298 K. The atomically clean Ag(100) surface is unreactive, while cesium su rfaces effect mainly dehydrogenation or selective oxidation with some metal -carbon bond formation, but with complete oxidation a minor pathway. Partia lly cesiated Ag(100) surfaces, on the other hand, result in complete oxidat ion to give surface carbonate at 160 K. Two key intermediates responsible f or the alternative reaction pathways have been delineated through their ver y different, but characteristic, C(1s) spectra at 80 K.