Oxygen transfer between metals and oxygen‐ion conducting supports

The charge‐transfer reactions in the three‐phase interfacial region, between a platinum catalyst, an yttria‐stabilized zirconia (YSZ) support, and the gas phase, were studied electrochemically during carbon monoxide oxidation. From electrochemical and reaction‐rate measurements, it appeared that oxygen was being removed from the support by carbon monoxide adsorbed on the platinum, while being supplied to the support by atomic oxygen adsorbed on either the platinum or the YSZ. Highly disperse Pt/YSZ catalyst outperformed a Pt/Al₂O₃ catalyst, the rate difference being explained in terms of interfacial reactions. Even in the presence of species such as water and sulfur dioxide, catalysts with YSZ supports outperformed those with alumina supports.