Styrene synthesis over iron oxide model catalysts was studied by combining UHV characterization methods with in-situ conversion measurements in a micro-flow reactor under realistic reaction conditions. Both unpromoted Fe2O3 and K-promoted model catalysts show a similar high starting activity while that of Fe3O4 is clearly lower. Water limits and K-promotion slows down deactivation by coking and oxide reduction. The deactivation can be prevented and the high initial yield preserved by adding a small amount of oxygen to the feed. Both the presence of Fe3+ and intermediate adsorption strength for ethylbenzene and styrene are essential for high conversion yields.
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