## 3 Results
### CO\({}_{2}\) Adsorption
As revealed from Table 5 and Figure 8, it is clear that the most critical parameters for high CO\({}_{2}\) adsorption are oxygen functionality, micropores percentage, and SV ratio; all samples with high adsorptions have relatively high all the above values. Apart from microporosity, the following important parameter that needs to be considered for high adsorptions is the O functionalities. It has been seen that these functionalities favor CO\({}_{2}\) adsorption. Similarly, the relation of the surface to the volume was significant, calculated as ratio surface area/volume (SV). For these calculations, the specific area measured by BET and the total volume of the pores was used. A sample with high SV (more active centers for adsorption) is expected to have higher adsorption. In the case of the same volumes, the higher SV ratio shows the different shapes of the porous system that can go from sphere to ellipsoid to cylindrical. For the same shape of porous, the highest SV ratio means a slimmer and thinner porous design. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline Sample & \begin{tabular}{c} CO\({}_{2}\) \\ vs. O \\ \end{tabular}  & \begin{tabular}{c} CO\({}_{2}\) \\ vs. S, Si, N, O \\ \end{tabular}  & \begin{tabular}{c} CO\({}_{2}\) \\ vs. Micro(\%) \\ \end{tabular}  & \begin{tabular}{c} CO\({}_{2}\) \\ vs. SSV \\ \end{tabular}  & \begin{tabular}{c} CO\({}_{2}\) \\ vs. SV \\ \end{tabular}  & \begin{tabular}{c} CO\({}_{2}\) \\ vs. Avg \(\Phi_{\sigma}\) \\ \end{tabular}  & \ \begin{tabular}{c} High Ads with \\ Green, \\ Medium with \\ Orange and Red, \\ Low \\ \end{tabular}  \\ \hline \hline \begin{tabular}{c} Possible \\ Connection \\ \end{tabular}  & \(\uparrow\) \(\%\) & \(\downarrow\) \(\uparrow\) \(\downarrow\) \(\uparrow\) \(\downarrow\) \(\uparrow\) \(\downarrow\) \(\uparrow\) \(\downarrow\)  
Hypothesizing samples with high O functionality (more than 23%), high microporosity percentage (more than 3.7%), and SV more than 0.345 showed the highest CO\({}_{2}\) adsorptions  
Figure 8: Comparison of CO\({}_{2}\) adsorption with: (**a**) oxygen functionality and ratio C/Heteroatoms; (**b**) percentages of micropores and macropores; (**c**) SV ratio and average pore diameter (dp). in this study. The medium for these parameters is 26.71% (oxygen functionality), 5.5% (micropores), and 0.374 (SV ratio). Concerning the other parameters that play a pretty important role in increasing CO\({}_{2}\) adsorption, the presence of the heteroatoms is also affected. Four out of six samples with the highest adsorption show the low ratio of C/S-Si-N-O (Table 5), meaning a higher presence of heteroatoms, except for rGO90_0.5 (but in this case, no heteroatoms from functionalization exist). Another more ambiguous parameter is the percentage of macroopores. It is believed that a high percentage of macroopores can help the gas diffuse through the meso and then to micropores. A wide range of macroopores that show high adsorption can be found, but this is also related to the micropores. Another important parameter is the average diameter of the pores, which is between 13.2 to 14.4 nm, except for sample SN60_0.5 that has 17.9 nm and has the fifth-highest adsorption. Moreover, the sample mentioned above also has one of the highest macroopores percentages, which increases the average pore diameter. Additionally, the samples that show high adsorptions are two blank ones, two modified with TMOS, one modified with TMON, and the last one with TMOSN. For the oxygen functionality, all samples follow the trend, except S90_2. In the case of ratio for the heteroatoms, the exception comes from rGO90_0.5, which does not have heteroatoms, except O. Microporosity is also a significant trend except for sample N60_0.5 that has a low percentage. In the case of macroporosity, the trend is not followed from sample S90_2. Ratio SV is high for all samples, except sample N60_0.5. Finally, the sample that is out of range for the ideal average pore diameter is the SN60_0.5.