Features and mechanism of atomic oxygen radical anion emission from yttria-stabilized zirconia electrolyte

Abstract Anion and electron emissions from Y 2 O 3 -stabilized ZrO 2 (YSZ) electrolyte were investigated by time of flight (TOF) spectroscopy. The atomic oxygen radical anion (O − ) is the only anion species emitted from the YSZ surface. The emission branch ratio between O – and electrons is close to one. The Arrehenius plots for both O – and electron emission, derived from the temperature dependences, exhibit double linear behavior. The apparent activation energies in the low-temperature region ( 620 °C). It was also found that the extraction field can enhance the O – emission. The maximum emission current density for O – is 3.5 nA/cm 2 in our investigated range. The observed O – and electron emissions are attributed to the dissociation of the intermediate anions, O 2– , present on the YSZ anode surface. The rate-determining step for the O – emission is believed to be the desorption process in the low-temperature region, and the electron desorption or the electrochemical reaction in the high-temperature region.