2D Single-Atom Fe–N–C Catalyst Derived from a Layered Complex as an Oxygen Reduction Catalyst for PEMFCs

Fe single-atom catalysts of oxygen reduction reaction (ORR) are restricted by the agglomeration during the synthesis process and inferior stability, especially in acidic conditions. An efficient synthesis strategy is urgently needed to alleviate these disadvantages. In this work, a two-dimensional (2D) single-atom Fe–N–C catalyst derived from a layered complex was designed and synthesized for the ORR. Fe single atoms dispersed on 2D hierarchical porous N-doped carbon nanosheets (Fe–N–C) were derived from a layered complex through the coordination of Fe3+ and benzidine hydrochloride. The unique 2D hierarchical porous nanosheets with a special edge effect can not only provide a large specific surface area and promote the mass transfer of ORR but also facilitate the affinity of Fe single atoms. Furthermore, the well-distributed Fe single atoms and Fe–Nx–C structure can increase the utilization rate of metal atoms and enhance the catalytic activity of materials. As expected, the catalyst shows superior ORR performance and excellent electrochemical stability.