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.