## 3 Results and Discussion
### Characteristics of the Graphene Materials
(2018) where the lower the starting G size, the higher the oxidation degree of the obtained GO, which could lead to a better exfoliation of rGO. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \(\mathbf{GO_{m}}\) & **Ramp** & **Atmosphere** & **Sample** & \(\mathbf{d_{(002)}}\) **(nm)** & \(\mathbf{N_{L}}^{*}\) & \(\mathbf{S_{BEI}}\) **(m\({}^{2}\) g\({}^{-1}\))** & **N (\%)** \\ \hline GO\({}_{325}\) & 1 & Inert & rGO\({}_{325}\)-1 & 0.35 & 13 & 767 & - \\  & 2 & & rGO\({}_{325}\)-2 & 0.35 & 10 & 804 & - \\  & 3 & & rGO\({}_{325}\)-3 & 0.34 & 12 & 867 & - \\  & 4 & & rGO\({}_{325}\)-4 & 0.35 & 17 & 667 & - \\  & 5 & & rGO\({}_{325}\)-5 & 0.36 & 26 & 866 & - \\ \hline GO\({}_{100}\) & 3 & Inert & rGO\({}_{100}\)-3 & 0.35 & 10 & 778 & - \\ \hline GO\({}_{10}\) & 3 & Inert & rGO\({}_{10}\)-3 & 0.34 & 18 & 505 & - \\ \hline GO\({}_{325}\) & 1 & Ammonia & NrGO\({}_{325}\)-1 & 0.34 & 14 & 428 & 4.8 \\  & 2 & & NrGO\({}_{325}\)-2 & 0.35 & 9 & 427 & 4.4 \\  & 3 & & NrGO\({}_{325}\)-3 & 0.34 & 14 & 460 & 5.0 \\  & 4 & & NrGO\({}_{325}\)-4 & 0.34 & 14 & 492 & 5.0 \\  & 5 & & NrGO\({}_{325}\)-5 & 0.34 & 13 & 476 & 4.1 \\ \hline GO\({}_{100}\) & 4 & Ammonia & NrGO\({}_{100}\)-4 & 0.35 & 10 & 420 & 3.8 \\ \hline GO\({}_{10}\) & 4 & Ammonia & NrGO\({}_{10}\)-4 & 0.34 & 40 & 236 & 1.8 \\ \hline \hline \end{tabular}  
* \(\mathbf{N_{L}}\)= (L\({}_{002}\) + d\({}_{002}\))/d\({}_{002}\).  
\end{table} 
Table 1: Interlayer distance d\({}_{(002)}\), estimated number of layers (N\({}_{L}\)), \(S_{\text{BEI}}\), and N content (%) for N doped and non-doped reduced graphene oxide samples. Figure 2: Representative SEM images of **(a)** GO\({}_{10}\), **(b)** GO\({}_{100}\) and **(c)** GO\({}_{325}\) samples. TEM micrographs for **(d)** rGO\({}_{10}\)-3, **(e)** rGO\({}_{100}\)-3, **(f)** rGO\({}_{325}\)-3, **(g)** NrGO\({}_{10}\)-4, **(h)** NrGO\({}_{100}\)-4 and **(i)** NrGO\({}_{325}\)-4 samples. NrGO: N-doped reduced graphene oxide, rGO: reduced graphene oxide. The completion of the exfoliation process for the prepared graphene materials was investigated by XRD. Examination of the rGO\({}_{325}\)-r and NrGO\({}_{325}\)-r patterns (Figure S2 ESI) indicates that the selected exfoliation ramps, 3 (inert) and 4 (ammonia), conduce to a successful exfoliation of the GO325 sample since the characteristic diffraction peak at 20\(\sim\)15\({}^{\circ}\) of GO (see Figure 1) disappeared, suggesting a reduction of GO325 to NrGO325 and rGO325 samples [10]. In addition, the absence of reflections corresponding to crystalline graphite for GO\({}_{325}\)-3 and NrGO\({}_{325}\)-4 samples supports the adequacy of ramps 3 (inert) and 4 (ammonia). The greater or lesser success in the GO exfoliation process can be evaluated by the appearance or not of crystalline graphite reflections. Figure 3 shows the XRD patterns of NrGO\({}_{\text{m}}\)-4 and rGO\({}_{\text{m}}\)-3. It can be seen that the exfoliation process was fully successful in inert atmosphere for all the GO and also in ammonia atmosphere, especially for the GO\({}_{100}\) and GO\({}_{325}\) samples, because only a small and broad peak appeared at 20 slightly lower than 26\({}^{\circ}\), corresponding to the graphite (002) reflection. This fact indicates that the sample contains some small restacking of graphene layers and the formation of a few-layer graphene structures. The intensity of this peak displays a progressive increase with the particle size of the GO starting material, showing a higher number of restacked layers (rGO\({}_{10}\) > rGO\({}_{100}\) \(\geq\) rGO\({}_{325}\)). Particularly, the progressive association of the graphene sheets produced after blasting is favored under ammonia reactive conditions but without reaching the level typical for crystalline graphite. This tendency is coherent with the values of S\({}_{\text{BET}}\).