Catalytic study and electrochemical promotion of propane oxidation on Pt/YSZ

The Pt-catalyzed oxidation of propane was studied in an oxygen ion conducting solid electrolyte cell at 623-773 K and atmospheric total pressure. Under open circuit, the solid electrolyte potentiometry (SEP) technique was used to monitor the thermodynamic activity of oxygen adsorbed on the catalyst surface during reaction. Reaction kinetics and SEP measurements were combined to elucidate the reaction mechanism. Under certain conditions, sustained oscillations in the reaction rate and the surface oxygen activity were observed. The reaction exhibited a strong non-Faradaic modification of catalytic activity (NEMCA) effect. By varying the potential of the Pt catalyst, the rate of propane oxidation could be reversibly enhanced by up to a factor of 1400. At positive potentials, the reaction exhibited a pronounced electrophobic NEMCA enhancement. At negative potentials, the reaction also exhibited a strong electrophilic enhancement, indicating that the promoting effect is of the "inverted volcano" type. (c) 2005 Elsevier Inc. All rights reserved.