Grain-resolved mapping of oxygen evolution activation on a Ni-superalloy

Abstract

We report the first grain-resolved mapping of oxygen evolution reaction (OER) activation on a Ni-based superalloy using identical-location EBSD, complemented by IL-SEM, IL-EDS, and SECCM. NiFe (oxy)hydroxide film formation and OER activity are strongly influenced by grain size and orientation, with (111)-oriented and smaller grains undergoing pronounced structural, chemical, and electrochemical transformations. These findings reveal pronounced microstructure heterogeneity in OER and establish IL-EBSD as a powerful tool for the microstructure-guided design of advanced electrocatalysts.