Perspective on the Relationship between the Acidity of Perovskite Oxides and Their Oxygen Surface Exchange Kinetics

The oxygen exchange reaction kinetics of a large number of ternary mixed ionic and electronic conducting oxides were analyzed with respect to their calculated surface acidity factors derived from the Smith acidity factors of the corresponding binary oxides from which the ternary oxides are composed. The analysis suggests that the surface exchange kinetics have a direct link to the acidity of the mixed conducting oxide. The possible interplay between acidity and transport properties is discussed. The analysis is also applied to oxygen evolution reaction (OER) electrocatalysts but does not show a link between OER overpotentials and acidity, suggesting that the link is more relevant for gas/oxide interactions at high temperatures. The observations suggest that acidity impacts most directly the oxygen adsorption process while impacting the electron charge transfer only indirectly.