Reconstructed parallel sites enhance the reactive oxygen tolerance of non-noble metal catalyst for durable proton exchange membrane fuel cells

The establishment of reactive oxygen species (ROS) elimination sites in iron-nitrogen-carbon (Fe-N-C) electrocatalysts to achieve durable proton-exchange membrane fuel cells (PEMFCs) performance has attracted broad interest. However, realizing ROS removal efficiency and oxygen reduction reaction (ORR) activity within a single system represents a significant challenge to date. Herein, we demonstrate uniform ROS elimination sites and ORR centers through an electrochemical reconstruction method on the parallel sites of Fe@CeNC electrocatalyst for durable PEMFC. During the reconstruction process, the Fe sites can retain their original configuration. Meanwhile, the pristine Ce clusters will evolve into more efficient, highly dispersed sites. Furthermore, the reconstructed Fe and Ce sites exhibit favorable energy barriers for the ORR and ROS elimination pathways, respectively, thereby maintaining ORR activity and achieving high ROS tolerance. Consequently, the PEMFC assembled with our catalyst shows only a 2% decay in power density after the accelerated durability test. We anticipate that this parallel structure design will provide new insight into the development of more durable electrocatalysts for PEMFCs.