Electrochemical promotion of Pt(1 1 1)/YSZ(1 1 1) and Pt–FeO_x/YSZ(1 1 1) thin catalyst films: Electrocatalytic, catalytic and morphological studies

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• 作者：E. Mutoro ; C. Koutsodontis ; B. Luerssen ; S. Brosda ; C.G. Vayenas ; J. Janek
• 关键词：Electrocatalysis ; EPOC ; Ethylene oxidation ; Iron additives ; Morphology ; NEMCA ; Platinum ; PLD ; Spillover ; YSZ
• 刊名：Applied Catalysis B: Environmental
• 出版年：2010
• 出版时间：11 October 2010
• 年：2010
• 卷：100
• 期：1-2
• 页码：328-337
• 全文大小：1377 K

文摘

The electrochemical promotion of ethylene oxidation on Pt was investigated using Pt(1 1 1) thin film model catalyst–electrodes deposited on top of YSZ(1 1 1) single crystals. This is the first study involving a thin epitaxial and well-characterized catalyst system. The nearly covering Pt films were prepared by pulsed laser deposition (PLD) and characterized by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction (XRD). In order to explore the influence of potentially catalytic active impurities, samples with and without FeO_x dopants on the Pt catalyst surface were investigated. A major result is that most of the samples showed unequivocal electrochemical promotion of catalytic activity (EPOC). The Faradaic efficiency values Λ are typically 2.5–77 which is considerably smaller than those reported for usually investigated macroscopically porous paste electrodes (Λ^max = 3 × 10⁵). This fact can be attributed to the much shorter three-phase boundary (tpb) length of the catalyst films. The iron-doped samples showed a permanent effect (P-EPOC). The results are discussed in terms of morphology changes and iron-doping effects. A short survey of EPOC studies using different catalyst/electrolyte preparation techniques is given.