Applied Voltage-Activated Fe─N─C Catalysts for Pem Fuel Cells

The practical application of non-precious Fe─N─C catalysts in proton exchange membrane fuel cells (PEMFCs) continues to remain one of the major challenges due to their relatively poor oxygen reduction reaction (ORR) performance in acid. In this work, a fast and facilely performance enhancement strategy is first proposed for various Fe─N─C catalysts by supplying different direct-current voltages to achieve a rapid solid-state activation at room temperature. The voltage-activated state-of-the-art Fe─N─C catalyst has demonstrated a peak power density of 1.1 W cm⁻² for PEMFC and remarkably increased long-term durability for ORR. The substantially improved performance can be attributed to the formation of highly active ketone-decorated (edge-hosted) FeN₄ sites and substantially boosts coupled proton−electron transfer (CPET) by improving the conductivity of the as-synthesized Fe─N─C with an interpenetrating network structure. The interconnected micro-nodes within the interpenetrating network are the main active regions for the ORR, evidenced by an optimized structural model based on the above typical morphology. Therefore, this finding provides an innovative and facile idea for solving the activity and stability deficiency for promising Fe─N─C for commercial PEMFC.