# Synthesis of Benzoxazine-Based N-Doped Mesoporous Carbons as High-Performance Electrode Materials
## 3 Results and Discussion
### Microstructure Characterization
The results of the XRD show that these carbon materials (NCM-700, NCM-800, NCN-900, and ACNCM-900) had an ordered and graphitized amorphous structure. The XRD also showed that these carbon materials (NCM-700, NCM-800, NCM-900, and ACNCM-900) had a similar structure to SBA-15. There were three well-resolved diffraction peaks (100, 110, and 200) in the small angle X-ray diffraction (Figure 5a), which showed that the NCM materials had a 2D hexagonal symmetry with the space group ppm. The wide-angle XRD of NCM-900 is shown in Figure 5b, which exhibited two diffraction peaks at 2\(\theta\) = 25\({}^{\circ}\) and 44\({}^{\circ}\) belonging to the (002) and (100) planes of hexagonal  
Figure 3: SEM images of (**a**) NCM-700, (**b**) NCM-800, (**c**) NCM-900, and (**d**) ACNCM-900; TEM images of (**e**) NCM-900 and (**f**) ACNCM-900. carbon, respectively [38; 39]. We could find the graphitized and amorphous carbon structures of the NCM-900 from the wide angle XRD. These structures could enhance the electrochemical properties. The nitrogen adsorption-desorption isotherms (Figure 5c) and pore size distribution (Figure 5d) indicated that these obtained carbon materials (NCM-700, NCM-800, NCM-900, and ACNCM-900) prepared using different carbonization temperatures and different precursors had typical type IV curves (according to the International Union of Pure and Applied Chemistry IUPAC classification) with a hysteresis loop (relative pressure, \(P/P_{0}=0.4\)-0.7) and a mesoporous structure [40]. The nitrogen adsorption-desorption isotherms of the four carbon materials were nearly similar in shape. Furthermore, compared with the curve of SBA-15 (Figure 5c), we found that the structure of the prepared carbon material came from the engraving of the template. From Figure 5d, for carbon materials prepared from the same precursor, the pore size distribution had no significant tendency even though the carbonization temperature was different. The average pore size was concentrated in the range 3.4-3.8 nm. As for the different precursors, ACNCM-900 had a larger average pore size than the NCM-900. This was because the low nitrogen content of ACNCM-900 indicated that fewer nitrogen-containing groups were carbonized during the carbonization process and fewer micropores were formed, thus the average pore size was slightly bigger. The corresponding specific surface area, average pore diameter, and total pore volume are listed in the Table 2. The specific surface areas of ACNCM-900 and NCM-900 were calculated to be 788.447 m\({}^{2}\)/g and 798.623 m\({}^{2}\)/g. The pore volumes of ACNCM-900 and NCM-900 were 1.376 cm\({}^{3}\)/g and 1.052 cm\({}^{3}\)/g. As can be seen from Table 2, the specific surface area and pore volume of carbon materials were higher than the template. The large specific surface area was beneficial for the diffusion and transportation of electrolyte ions. Figure 4: XPS spectra of nitrogen-doped mesoporous carbons (**a**) NCM-900 and (**b**) ACNCM-900. _Appl. Sci._**2020**, _10_, 422 \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Samples** & **C (\%)** & **O (\%)** & **N (\%)** \\ \hline ACNCM-900 & 93.88 & 4.64 & 1.48 \\ NCM-900 & 89.20 & 5.85 & 4.95 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: XPS peak analysis of the carbon samples. Figure 5: _Cont._