Boost the Utilization of Dense FeN₄ Sites for High‐Performance Proton Exchange Membrane Fuel Cells

Abstract

Iron‐nitrogen‐carbon (Fe‐N‐C) catalysts for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs) have seriously been hindered by their poor ORR performance of Fe‐N‐C due to the low active site density (SD) and site utilization. Herein, we reported a melamine‐assisted vapor deposition approach to overcome these hindrances. The melamine not only compensates for the loss of nitrogen caused by high‐temperature pyrolysis but also effectively etches the carbon substrate, increasing the external surface area and mesoporous porosity of the carbon substrate. These can provide more useful area for subsequent vapor deposition on active sites. The prepared 0.20Mela‐FeNC catalyst shows a fourfold higher SD value and site utilization than the FeNC without the treatment of melamine. As a result, 0.20Mela‐FeNC catalyst exhibits a high ORR activity with a half‐wave potential (E1/2) of 0.861 V and 12‐fold higher ORR mass activity than the FeNC in acidic media. As the cathode in a H2‐O2 PEMFCs, 0.20Mela‐FeNC catalyst demonstrates a high peak power density of 1.30 W cm−2, outstripping most of the reported Fe‐N‐C catalysts. The developed melamine‐assisted vapor deposition approach for boosting the SD and utilization of Fe‐N‐C catalysts offers a new insight into high‐performance ORR electrocatalysts.

MnO synergizes with FeC–FeN in carbon nanofibers to boost oxygen reduction for zinc–air batteries

“…The development of efficient catalysts for the oxygen reduction reaction (ORR) plays a key role in promoting the widespread use of Zn-air batteries. [1][2][3][4] Currently, commercial ORR catalysts are mainly based on platinum (Pt)-based materials, which are disadvantageous due to their high cost and unsatisfactory durability. [5][6][7] Therefore, it is essential to develop low-cost, high-performance, and non-noble metal oxygen reduction catalysts, but this is still a challenging undertaking.…”