fig3

Figure 3. A: The EPR spectra of different reaction systems with DMPO as radical trap; B: The ultraviolet-visible absorption spectra of the reaction system (with and without catalyst) after adding DPD and POD; C: ATR-IR spectrum of catalytic systems with I as reactant, 1,10-phenanthroline as model catalyst and toluene as solvent under 140 °C in O₂ for 1, 2, 3, 4 and 5 h, respectively; D: Schematic representation of the proposed mechanism of N-doped sp³@sp² nanocarbon catalyzed aerobic synthesis of 2-substituted benzoxazoles.