caa a22 4500 475844432 CHVBK 20180406123910.0 cr unu---uuuuu 170329e20000701xx s 000 0 eng 10.1023/A:1009041107437 doi (NATIONALLICENCE)springer-10.1023/A:1009041107437 An integrated surface science approach towards metal oxide catalysis [Elektronische Daten] [Werner Weiss, Robert Schlögl] The function of a metal oxide catalyst was investigated by an integrated approach, combining a variety of surface science techniques in ultrahigh vacuum with batch reactor conversion measurements at high gas pressures. Epitaxial FeO(111), Fe3O4(111) and α‐Fe2O3(0001) films with defined atomic surface structures were used as model catalysts for the dehydrogenation of ethylbenzene to styrene, a practized selective oxidation reaction performed over iron‐oxide‐based catalysts in the presence of steam. Ethylbenzene and styrene adsorb onto regular terrace sites with their phenyl rings oriented parallel to the surface, where the π‐electron systems interact with Lewis acidic iron sites exposed on Fe3O4(111) and α‐Fe2O3(0001). The reactant adsorption energies observed on these films correlate with their catalytic activities at high pressures, which indicates that the surface chemical properties do not change significantly across the pressure gap. Atomic defects were identified as catalytically active sites. Based on the surface spectroscopy results a new mechanism was proposed for the ethylbenzene dehydrogenation, where the upward tilted ethyl group of flat adsorbed ethylbenzene is dehydrogenated at Brønsted basic oxygen sites located at defects and the coupling of the phenyl ring to Fe3+ terrace sites determines the reactant adsorption-desorption kinetics. The findings are compared to kinetic measurements over polycrystalline catalyst samples, and an extrapolation of the reaction mechanism found on the model systems to technical catalysts operating under real conditions is discussed. The work demonstrates the applicability of the surface science approach also to complex oxide catalysts with implications for real catalysts, provided suitable model systems are available. Kluwer Academic Publishers, 2000 iron oxides nationallicence surface structure nationallicence temperature‐programmed reaction nationallicence model catalysis nationallicence pressure gap nationallicence ethylbenzene nationallicence Weiss Werner Fritz‐Haber‐Institut der Max‐Planck‐Gesellschaft, Faradayweg 4‐6, 14195, Berlin, Germany aut Schlögl Robert Fritz‐Haber‐Institut der Max‐Planck‐Gesellschaft, Faradayweg 4‐6, 14195, Berlin, Germany aut Topics in Catalysis Kluwer Academic Publishers-Plenum Publishers 13/1-2(2000-07-01), 75-90 1022-5528 13:1-2<75 2000 13 11244 https://doi.org/10.1023/A:1009041107437 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1009041107437 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Weiss Werner Fritz‐Haber‐Institut der Max‐Planck‐Gesellschaft, Faradayweg 4‐6, 14195, Berlin, Germany aut NATIONALLICENCE 700 1- Schlögl Robert Fritz‐Haber‐Institut der Max‐Planck‐Gesellschaft, Faradayweg 4‐6, 14195, Berlin, Germany aut NATIONALLICENCE 773 0- Topics in Catalysis Kluwer Academic Publishers-Plenum Publishers 13/1-2(2000-07-01), 75-90 1022-5528 13:1-2<75 2000 13 11244 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer