By experimental data and computational calculations, Kepp et al., have indicated that metal-oxygen interactions are in an order of Co, Cu, and Ag with bond dissociation enthalpy with oxygen of 420, 310, and 200 kJ/mol, respectively. Given stronger affinity to oxygen, more active oxygen was absorbed on the Co/SiO2 surface and reacted with N2 * to form nitrous oxide while the reactions occurred over the Cu/SiO2 presented weak intensity of nitrous oxide, as shown in Fig. . For the metals with weaker affinity such as Ag or Cu, active oxygen was possibly prone to recombination with H atoms. These conclusions can be verified via the selectivity of N2O and NH3 (Fig. ). The N2O calibration curve is also shown in Fig. . At N2 input flowrate of 6.2 sccm and 6 W, the Ag/SiO2 and Co/SiO2 catalysts displayed lower N2O selectivity of 27.5 and 32.0%, respectively than that of the SiO2 and the Cu/SiO2, which produced the N2O selectivity of 47.6 and 41.8%, respectively (Eq.( ), Supporting Information).