Hypervelocity kinetics blocks harmful intermediates to enhance stability of Fe-N-C catalysts

Hydrogen peroxide that is produced through the two-electron pathway during the catalysis of oxygen reduction reaction (ORR) is recognized as harmful to the stability of nitrogen-doped carbon and Fe-based nonprecious catalyst (Fe-N-C) for fuel cell application. A major remaining scientific question is how fast the removal of these deleterious intermediates can contribute to stability enhancement. Here, we report that the stability of Fe-N-C catalysts is positively correlated with the kinetic constant of hydrogen peroxide decomposition. Modulation of the H₂O₂ decomposition kinetics by applying the frequency factor of the Arrhenius equation from 800 to 30000 s⁻¹ for TiO₂, CeO₂ and ZrO₂ reduced the decay rate of Fe-N-C catalysts from 0.151% to −0.1% in a 100-hour stability test. Fe-N-C/ZrO₂ with a frequency factor of 30000 s⁻¹ showed a 10% increase in current density during a 100-hour stability test and almost no decay during 15 hours of continuous fuel cell operation at a high potential of 0.7 V.