Embedding coupled Pd/Fe sites in electrospun MOF-derived carbon nanofibers achieves efficient and durable oxygen reduction catalysis.

Abstract

High costs, poor durability of Pt electrocatalysts, and the low performance of non-precious metals hinder the large-scale commercialization of fuel cells. To address these challenges, a bimetallic, highly dispersed catalyst containing  Pd and Fe uniformly distributed on porous nitrogen-doped carbon nanofibers was developed. This catalyst demonstrated remarkable oxygen reduction catalytic performance. The Pd-Fe-N-C catalyst exhibited catalytic activity 4.6 times higher than that of the JM 20% Pt/C catalyst, despite containing only 0.62 wt% Pd. Moreover, it achieved a half-wave potential (E1/2 = 0.953 V vs. RHE) that is 40 mV higher than the JM 20% Pt/C catalyst (0.913 V vs. RHE). Significantly, with a total metal content of just 1.19 wt%, the E1/2 of Pd-Fe-N-C catalyst decreased by only 1 mV after 10,000 cycles, highlighting its exceptional durability. Furthermore, a stability test revealed a current retention rate of 84.87% after 50,000 s of operation, with no evidence of agglomeration. These results suggest that combining electrostatic spinning of MOFs with pyrolysis provides an effective and innovative method for synthesizing electrocatalysts with reduced reliance on precious metals.