Visualization of Co-O/N Sites under a Confined Combustion Strategy for Oxidation Reactions

The formation and excitation of metal sites in thermal fields are recognized as crucial for investigating catalyst structure-activity relationships. Herein, full Co₃O₄ (PC-345) was synthesized through a confined combustion strategy. The Co-O coordination structure in octahedral Co₃O₄ was regulated by nitrogen doping, which enhanced oxygen vacancy generation under thermal conditions and improved the catalytic activity for ethane (T₉₀% = 218 °C) and propylene (T₉₀% = 176 °C). Superior performance was demonstrated by Co₃O₄ (PC-345), including better-matched Fermi energy (-1.62 eV), reduced charge transfer resistance (0.24 Ω), and increased specific capacitance (28.77 F/g), suggesting enhanced electron availability, accelerated charge transfer, and additional catalytic sites. Water molecule migration was accelerated through *OOH to *+H₂O conversion, facilitated by extended bond lengths (2.06 Å) and lowered energy barriers (0.1 eV) at the Co-O/N sites. The evolution of Co-O/N sites was found to conform to the Avrami-Erofeev model of random nucleation and growth, as verified by thermal analysis kinetics and wavelet transforms. High correlation coefficients (R² > 0.92) between synthesis parameters (E_S) and catalytic performance (E_C) indicated an effective bridging of the energy barrier through Co-O/N mediation in thermal fields. These findings emphasize the importance of in situ thermal control for developing efficient low-temperature catalysts.