Stabilizing Fe single atom catalysts by implanting Cr atomic clusters to boost oxygen reduction reaction

Fe single-atom catalysts (SACs) have emerged as a promising alternative to platinum for catalyzing oxygen reduction reactions (ORR). Nevertheless, their practical applicability is hindered by insufficient stability caused by structural corrosion during ORR. Here, we developed an effective strategy to optimize and stabilize the Fe SAs (single-atoms) sites by implanting chromium (Cr) atomic clusters (ACs) to address the formidable deactivation issue of the best-performing yet unstable Fe-N-C catalysts. Cr_AC-Fe₁/N-S-C demonstrates an amazing stability with a negligible decline in activity after 100,000 CV cycles, and can maintain 81% of initial current after a continuous 50-hour operation period. Theoretical calculations and experimental evidence substantiate that the integration of Cr ACs not only weakens the binding of OH* to the Fe site, thereby facilitating the ORR process, but also eliminates in situ-generated reactive oxygen species (ROS) and retards Fe ion leaching from active sites, thus stabilizing of the Fe SA sites.