  The correlation between ex situ electronic conductivity, oxygen vacancy
content, flat-band potential (Efb), and the oxygen evolution reaction (OER)
activity for a wide range of perovskite compositions are investigated
experimentally and theoretically. It is found that all of these parameters can
affect the OER activity; however, none of them alone play a crucial role in
determining the electrocatalytic activity. The correlation of one single
physicochemical property with the OER activity always presents deviation
points, indicating that a limitation does exist for such 2-dimensional
correlations. Nevertheless, these deviations can be explained considering other
physicochemical properties and their correlation with the OER activity. Hence,
this work aims in simultaneously linking the OER activity with several
physicochemical materials properties. The concept of the OER/multidescriptor
relationship represents a significant advancement in the search and design of
highly active oxygen evolution catalysts, in the quest for efficient anodes in
water electrolyzers.
