Fe-N-C Electrocatalyst and Its Electrode: Are We Talking about the Same Material?

Evaluation of the electrocatalyst performance data includes an electrode preparation step. Herein, we compare the structural composition of Fe-N-C materials, used to electrocatalyze the oxygen reduction reaction in proton-exchange membrane fuel cells, before and after catalyst layer preparation. The effects of this step on the electronic structure and local coordination of Fe were investigated by X-ray absorption (XAS) and emission spectroscopies (XES), for Fe-N-C materials prepared via different synthetic routes. This work underlines the importance of determining the Fe-N-C catalyst structure in the prepared electrode for further studies of the structure-activity-stability correlations.