Styrene synthesis: In situ characterization and reactivity studies of unpromoted and potassium-promoted iron oxide model catalysts

Styrene synthesis over iron oxide model catalysts was studied by combining UHV characterization methods with in situ conversion measurements in a microflow reactor under realistic reaction conditions. Both unpromoted Fe ₂O₃ 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.