Fig. 4: Reactive species generation pathway.

In situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) spectra in Mn–Fe–NC/O3 (A). In situ Raman spectra in Mn–Fe–NC/O3 (B). Free energy diagrams of O3 evolution in MnN3–Fe1@FeN4 (C). Optimized structures for the O3 activation process on MnN3–Fe1@FeN4 with potential energy profiles (D). Computed Bader charge transfer of MnN3–Fe1@FeN4 to binding ozone (E).