Direct proof of potential dependent oxygen adsorption on a gold electrode surface by electrochemical quartz crystal microbalance

Potential dependent adsorption of oxygen on a gold electrode surface was proved by electrochemical quartz crystal microbalance. The adsorption of oxygen was started to be observed at potentials more positive than the potential where ORR started to take place and the amount of adsorbed oxygen increased and reached the saturated value as potential became more negative. The critical potentials, at which oxygen adsorption was started to be observed, were dependent on anions in solution. The adsorption of oxygen started at more positive potential in perchlorate solution than in sulfate solution, showing the inhibition of the adsorption of oxygen by strongly adsorbed sulfate anion. Keywords: Au electrode, Oxygen adsorption, Electrochemical quartz crystal microbalance