Fig. 6. A typical XPS spectrum of the C1s Purmorphamine state for the AC-modified SiCN obtained at 1200°C.Figure optionsDownload full-size imageDownload as PowerPoint slide
Chemical bonds in the AC-modified SiCN, calculated based on C1s state.Pyrolysis Temperature (°C)1000 °C1100 °C1200 °C1300 °C1400 °CCC28.32%31.35%31.55%27.81%23.42%C–C/H13.87%14.59%14.97%13.02%13.29%Full-size tableTable optionsView in workspaceDownload as CSV
The sp3–sp2 transition can be described by the following reaction :equation(2)sp3→sp2sp3→sp2
Its equilibrium equation can be written as:equation(3)[sp2]/[sp3]=K=K0exp(−μ/kT)where [sp3] and [sp2] are the concentrations of the sp3 and sp2, respectively, K the equilibrium constant, K0 is an coefficient, and μ the activation energy. Fig. 7 plots the sp2/sp3 ratio as a function of pyrolysis temperature for both AC-modified and unmodified SiCNs. It is seen that the data for the unmodified SiCN follows the Arrhenius relation very well. The activation energy measured to be 3.47 eV. However, for the AC-modified SiCN, the sp2/sp3 ratio remains almost the same regardless of pyrolysis temperature.