Oxophilic Yb ₂ O ₃ nanoparticles as radical scavengers to enhance the durability of Fe–N–C oxygen reduction catalysts

The practical application of Fe–N–C catalysts in proton exchange membrane fuel cells is substantially limited by their susceptibility to radical‐induced degradation of the active Fe–N 4 sites, which severely compromises long‐term durability. To address this issue, we report a strategy of immobilizing Yb 2 O 3 nanoparticles as efficient radical scavengers adjacent to Fe–N 4 sites. The remarkable scavenging capability of Yb 2 O 3 , surpassing that of conventional cerium oxide, is attributed to its favorable oxophilicity, which facilitates radical capture and conversion. The resulting Fe–NC/Yb 2 O 3 catalyst exhibits outstanding oxygen reduction reaction performance, featuring an initial half‐wave potential of 0.809 V and a negligible decay of only 19 mV after 10,000 cycles. In H 2 –air fuel cell tests, it retains 87.1% of its initial current density at 0.5 V over 20 h. Theoretical calculations indicate that the performance enhancement stems from strengthened radical adsorption and an optimized d ‐band center of the Fe–N 4 sites induced by Yb 2 O 3 . This work pioneers the use of a lanthanide sesquioxide for fuel cell catalyst protection, offering an effective strategy to overcome the activity–stability trade‐off in non‐precious metal catalysts.