Unveiling the high-activity origin of single-atom iron catalysts for oxygen reduction reaction

Abstract

Significance We propose a surfactant-assisted method to synthesize single-atom iron catalysts (SA-Fe/NG) supported on nitrogen-doped graphitic carbons, and experimentally demonstrated that the SA-Fe/NG catalyst possesses extremely outstanding catalytic activities for oxygen reduction reaction (ORR) in both acidic and alkaline media. Impressively, both the SA-Fe/NG-based acidic proton exchange membrane fuel cell and Zn-air battery show excellent performance. Combining experimental results and density-functional calculations, we reveal that the origin of high-ORR activity of SA-Fe/NG is from the Fe-pyrrolic-N 4 active species. The universal surfactant-assisted method can be easily extended to synthesis of other single-atom catalysts, and unveiling the origin of high-ORR activity of SA-Fe/NG will open an approach for developing other heterogeneous catalysts.