Effects of ratio of oxygen partial pressure to propane partial pressure and temperature on non-faradaic electrochemical modification of catalytic activity (nemca) of propane oxidation on Pt-YSZ

Abstract

The effects of electrochemical promotion of catalysis (EPOC) or non-faradaic electrochemical modification of catalytic activity (NEMCA) of sputtered-Pt catalyst on Y2O3-stabilized-ZrO2 (YSZ) disk, an O2- conductor, were studied with the catalytic reaction of propane oxidation, which was chosen to model the combustion of residual hydrocarbons in catalytic converters. In electrochemical promotion, the catalyst was electrochemically promoted by applying electric current or potential between the Pt and Au electrodes of YSZ disk. Catalytic performances were studied under the ratio of oxygen partial pressure to propane partial pressure difference of 1 to 5 and partial pressure of propane was 1 kPa, in the range of temperature of 200–500 °C by application of electrical potential of -1 to 1 V. The induced rate increase (r-r0) exceeded the electrochemically controlled rate I/nF of O2- transfer through the solid electrolyte, resulting in the faradaic efficiency Ʌ = (r-r0)/(I/nF) up to 2.96 × 105 achieved at 200 °C with cell voltage of 0.2 V for the ratio of oxygen partial pressure to propane partial pressure of 5 kPa. At high PO2, the reaction exhibited electrophobic type of NEMCA. At low PO2, the reaction also exhibited electrophilic type.