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Ionics

, Volume 1, Issue 5–6, pp 414–420 | Cite as

Electrochemical promotion of catalyst surfaces deposited on ionic and mixed conductors

  • A. C. Kaloyannis
  • C. A. Pliangos
  • D. T. Tsiplakides
  • I. V. Yentekakis
  • S. G. Neophytides
  • S. Bebelis
  • C. G. Vayenas
Article

Abstract

The effect of non-Faradaic electrochemical modification of catalytic activity (NEMCA) or electrochemical promotion (EP) was investigated on Pt films deposited on Y2O3-stabilized-ZrO2 (YSZ), an O2− conductor, TiO2, a mixed conductor, and Nafion 117 solid polymer electrolyte (SPE), a H+ conductor and also on Pd films deposited on YSZ and β″-Al2O3 a Na+ conductor. Four catalytic systems were investigated, i.e. C2H6 oxidation on Pt/YSZ, C2H4 oxidation on Pd/YSZ and Pd/β″-Al2O3, C2H4 oxidation on Pt/TiO2 and H2 oxidation on Pt/Nafion 117 in contact with 0.1 M aqueous KOH solution.

In all cases pronounced and reversible non-Faradaic electrochemical modification of catalytic rates was observed with catalytic rate enhancement up to 2000% and Faradaic efficiency values up to 5000.

All reactions investigated exhibit a pronounced electrophobic behaviour which is due to the weakening of chemisorptive oxygen bond at high catalyst potentials. Ethane oxidation, however, also exhibits electrophilic behaviour at low potentials due to weakened binding of carbonaceous species on the surface.

The general features of the phenomenon are similar for all four cases presented here showing that the NEMCA effect is a general, electrochemically induced, promoting catalytic phenomenon not depending on the reaction and the type of supporting electrolyte.

Keywords

TiO2 C2H4 Oxidation Solid Polymer Electrolyte Catalytic Rate Chemisorptive Oxygen 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© IfI - Institute for Ionics 1995

Authors and Affiliations

  • A. C. Kaloyannis
    • 1
  • C. A. Pliangos
    • 1
  • D. T. Tsiplakides
    • 1
  • I. V. Yentekakis
    • 1
  • S. G. Neophytides
    • 1
  • S. Bebelis
    • 1
  • C. G. Vayenas
    • 1
  1. 1.Department of Chemical EngineeringUniversity of PatrasPatrasGreece

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