Metal-organic framework-polymer complex-derived single-atomic oxygen reduction catalyst for anion exchange membrane fuel cells

Metal -nitrogen -doped carbon (M -N -C) catalysts have emerged as highly active noble -metal -free catalysts for oxygen reduction reactions (ORR) in anion -exchange membrane fuel cells (AEMFCs). However, the performance of existing M -N -C catalysts is limited by the inaccessibility of internal M-Nx active sites and loss of nitrogen doping after the carbonization process. Here, a single -atom Co, Fe and N -doped porous carbon catalyst (CoFe-NCPPy) were constructed using a complex of metal-organic frameworks (MOFs) and polypyrrole (PPy). As a new approach, we synthesized MOF and PPy composites by combining in situ MOF synthesis and pyrrole polymerization in a one -pot reaction. Through pyrolysis, the PPy and MOF composites demonstrated an enhanced specific surface area, a high active -site density, and a high concentration of nitrogen species in the M -N -C catalyst. These contributed to a superior ORR performance (E1/2 of 0.915 V) and high durability in alkaline media. Additionally, the CoFe-NC-PPy material studied in an AEMFC enabled high performance with a current density of 550 mA cm -2 at 0.6 V and a peak power density of 352 mW cm -2. This study suggests potential in combining polymers and MOFs in the synthesis of ORR catalysts for fuel cells.