ORALS

SESSION: PhysicalThuPM2-R10	Vayenas International Symposium on Physical Chemistry and its applications for sustainable development
Thu Oct, 24 2019 / Room: Aphrodite B (100/Gr. F)
Session Chairs: Vasileios Kyriakou; Dimitrios Zagoraios; Session Monitor: TBA

17:10: [PhysicalThuPM212]
Electrochemical Promotion of Methane Oxidation over Nanodispersed Pd/Co3O4 Catalysts
Dimitrios Zagoraios¹ ; Dimitrios Zagoraios² ; Alexandros Katsaounis³ ; Angel Caravaca⁴ ; Ioanna Kalaitzidou⁴ ; Athanasia Athanasiadi⁵ ; Spyros Ntais⁴ ; Philippe Vernoux⁶ ; Constantinos Vayenas² ; ¹University of Patras, Dept. of Chemical Engineering, Patras, Greece; ²University of Patras, Patras, Greece; ³Department of Chemical Engineering, University of Patras, Patras, Greece; ⁴University of Lyon, Lyon, France; ⁵University of Patras Dept. of Chemical Enginnering, Patras, Achaia, Greece; ⁶University LYON 1, Lyon, France;
Paper Id: 59 [Abstract]

During the last two decades, the Electrochemical Promotion of Catalysis (EPOC) phenomenon has been studied extensively for many catalytic reactions, including hydrocarbon oxidation reactions and hydrogenations [1-3]. The EPOC effect is based on the modification of the work function of a metal, which also serves as a working electrode, leading to an alteration in the chemisorption bond strength of the reactants. This effect is observed when small currents or potentials are applied to a catalyst deposited on a solid electrolyte. In the majority of the studies, the catalysts/electrodes consisted of porous noble metal films (Pt, Pd, Rh) prepared, for instance, by calcination of organometallic pastes [4]. This results in low metal dispersion and low active surface area, therefore limiting the overall catalytic activity. In view of further practical application of the EPOC phenomenon to industrial catalysts, we should be able to enhance the activity of nanodispersed materials. In this study, for the very first time, we observed an enhanced catalytic activity of a Pd nanodispersed catalyst supported on a porous Co₃O₄ semiconductor film. The Pd/Co₃O₄ composite powder was deposited on an yttria-stabilized zirconia (YSZ) solid electrolyte without the presence of an interlayer film. The observed enhancement was non-Faradaic, with apparent Faradaic efficiency values as high as 80. The Pd/Co₃O₄ catalyst was characterized thoroughly by means of a wide variety of physicochemical techniques, such as TEM, SEM, TGA, ICP and BET. Using supported catalysts as catalytic films for electrochemical promotion studies may lead to the practical utilization of EPOC in the chemical industry or in gas exhaust treatment.

References:
[1] C.G. Vayenas, S. Bebelis, I.V. Yentekakis, H.G. Lintz, Catal. Today. 11 (1992) 303-438.\n[2] C.G. Vayenas, S. Bebelis, C. Pliangos, S. Brosda, D. Tsiplakides Electrochemical Activation of Catalysis: Promotion, Electrochemical Promotion and Metal-Support Interactions, Kluwer Academic/Plenum Publishers, New York, 2001.\n[3] C.G. Vayenas, J. Solid State Electrochem. 7-8 (2011) 1425-1435.\n[4] C. Jimenez-Borja, S. Brosda, F. Matei, M. Makri, B. Delgado, F. Sapountzi, D. Ciuparu, F. Dorado, J.L. Valverde, C.G. Vayenas, Appl. Catal. B Environ. 128 (2012) 48-54.