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.