Investigation of the state of the electrochemically generated adsorbed O species on Au films interfaced with Y2O3-doped-ZrO2

Adsorbed O species on Au interfaced with Y₂O₃-doped-ZrO₂ are generated by electrochemical O²⁻ supply. It was found that two oxygen chemisorbed states are formed, which desorb at 420 °C (state α) and 550 °C (state β) with activation energies of desorption ranging between 115–145 kJ/mol and 235–270 kJ/mol, respectively. The strong interaction of the β-state O species with the Au surface causes an over 600 mV increase in Au surface potential and work function while the α-state O species is formed at even more positive catalyst-electrode potential. State α is attributed to normally adsorbed atomic O while the more ionic state β is only created electro-chemically and is mainly responsible for the work function increase of the Au catalyst-electrode surface. Their desorption activation energies of both states decrease linearly with increasing catalyst-electrode potential with slopes of the order of four. Paper presented at the 7th Euroconference on Ionics, Calcatoggio, Corsica, France, Oct. 1–7, 2000.