title: Lanthanoid-free perovskite oxide catalyst for dehydrogenation of ethylbenzene working with redox mechanism.
abstract: For the development of highly active and robust catalysts for dehydrogenation of ethylbenzene (EBDH) to produce styrene; an important monomer for polystyrene production, perovskite-type oxides were applied to the reaction. Controlling the mobility of lattice oxygen by changing the structure of Ba1 - x SrxFe y Mn1 - y O3 - δ (0 ≤ x ≤ 1, 0.2 ≤ y ≤ 0.8), perovskite catalyst showed higher activity and stability on EBDH. The optimized Ba/Sr and Fe/Mn molar ratios were 0.4/0.6 and 0.6/0.4, respectively. Comparison of the dehydrogenation activity of Ba0.4Sr0.6Fe0.6Mn0.4O3 - δ catalyst with that of an industrial potassium promoted iron (Fe-K) catalyst revealed that the Ba0.4Sr0.6Fe0.6Mn0.4O3 - δ catalyst showed higher initial activity than the industrial Fe-K oxide catalyst. Additionally, the Ba0.4Sr0.6Fe0.6Mn0.4O3 - δ catalyst showed high activity and stability under severe conditions, even at temperatures as low as 783 K, or at the low steam/EB ratio of 2, while, the Fe-K catalyst showed low activity in such conditions. Comparing reduction profiles of the Ba0.4Sr0.6Fe0.6Mn0.4O3 - δ and the Fe-K catalysts in a H2O/H2 atmosphere, reduction was suppressed by the presence of H2O over the Ba0.4Sr0.6Fe0.6Mn0.4O3 - δ catalyst while the Fe-K catalyst was reduced. In other words, Ba0.4Sr0.6Fe0.6Mn0.4O3 - δ catalyst had higher potential for activating the steam than the Fe-K catalyst. The lattice oxygen in perovskite-structure was consumed by H2, subsequently the consumed lattice oxygen was regenerated by H2O. So the catalytic performance of Ba0.4Sr0.6Fe0.6Mn0.4O3 - δ was superior to that of Fe-K catalyst thanks to the high redox property of the Ba0.4Sr0.6Fe0.6Mn0.4O3 - δ perovskite oxide.
authors.affiliation: Department of Materials Science and Chemical Engineering, Faculty of Engineering, Shizuoka University Hamamatsu, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Watanabe
authors.affiliation: Department of Applied Chemistry, School of Science and Engineering, Waseda University Tokyo, Japan.
authors.forename: Maiko
authors.initials: M
authors.lastname: Ikushima
authors.affiliation: Department of Applied Chemistry, School of Science and Engineering, Waseda University Tokyo, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Mukawa
authors.affiliation: Department of Applied Chemistry, School of Science and Engineering, Waseda University Tokyo, Japan.
authors.forename: Fumitaka
authors.initials: F
authors.lastname: Sumomozawa
authors.affiliation: Department of Applied Chemistry, School of Science and Engineering, Waseda University Tokyo, Japan.
authors.forename: Shuhei
authors.initials: S
authors.lastname: Ogo
authors.affiliation: Department of Applied Chemistry, School of Science and Engineering, Waseda University Tokyo, Japan.
authors.forename: Yasushi
authors.initials: Y
authors.lastname: Sekine
keywords: dehydrogenation of ethylbenzene; lattice oxygen; perovskite oxide catalyst; redox mechanism; stable under severe conditions; styrene production