## 4 Results and Discussion
The interlayer spacing d\({}_{002}\) can be calculated from the position of the (002) band using Bragg's Law, as follows:  
\[\text{n}\cdot\lambda=2\text{d}_{\text{hkl}}\sin(\theta)\]  
where  
\(\text{n}\)--order of diffraction, equal to 1 here  
The average number of layer planes in the pseudocrystallites can be calculated by dividing Lc by d\({}_{002}\). The interlayer spacing is the same for all the AC and was equal to 0.36 nm, demonstrating a significant deviation from the dimensions observed in graphene (0.334 nm). The pseudocrystallite height (Lc) and width (La) were equal to 1.2 and 3.9 nm, respectively. The average number of layer planes is calculated as 3. The values of interlayer spacing, the pseudocrystallite height and width, and the average number of layer planes are typical for poorly graphitized and non-graphitizing carbons [41]. All activated carbons exhibited a similar porous structure. In the SEM images (Figure 9), clear entrances to macropores are visible, likely sequentially leading to mesopores and micropores. It was observed that cold plasma treatment did not alter the morphology of the DT0 carbon. Figure 9: SEM pictures of pristine plasma samples (DT0) and those modified by N2 (DT0_1, DT0_2). FTIR spectra of pristine plasma samples (DT0) and those modified by N2 (DT0_1, DT0_2) are presented in Figure 6:0 The presence of numerous N-containing groups resulting from interactions between N2 plasma and surface functional groups has been validated through FT-IR analysis. The pronounced and extensive spectral features observed at approximately 3400 cm\({}^{-1}\) are attributed to symmetric stretching vibrations of N-H bonds and/or the presence of hydrogen-bonded hydroxyl nests [42]. The spectral analysis reveals discernible bands in the range of about 1441  cm\({}^{-1}\), which are ascribed to amides, pyridine, and C=N functionalities [43]. Moreover, discernible peaks manifest in the spectral region spanning about 1100 cm\({}^{-1}\), corresponding to the stretching vibrations of C-N single bond bonds [44]. The spectral band observed within about 880 cm\({}^{-1}\) is indicative of out-of-plane N-H deformation vibrations [45]. Consequently, the Fourier-transform infrared (FT-IR) analysis corroborates the presence of numerous nitrogen-containing groups within the carbon samples. Therefore, the FT-IR analysis substantiates the presence of N-H, amide, pyridine, C = N, and C -N species in all the samples. All of the bands listed above are more intense for samples modified by N2 plasma. This observation indicates the successful introduction of nitrogen functional groups in comparison to the pristine sample  
In summary, regarding the properties of the investigated carbons, it should be emphasized that their textural parameters and pseudocrystal sizes remained essentially unchanged due to plasma treatment. Only the nitrogen content increased, as confirmed using elemental analysis and FTIR spectroscopy. This enables the investigation of the sole influence of nitrogen presence on CO2 adsorption. This study involved the analysis of pristine and modified activated carbons with regard to their adsorption of CO2. Tests were conducted at temperatures of 0 and 30 \({}^{\circ}\)C under pressures up to 100 kPa. The findings are illustrated in Figure 6:1  
For all activated carbon, CO2 adsorption isotherms at temperatures of 0 and 30 \({}^{\circ}\)C, demonstrate a comparable trend. These isotherms showed a rapid rise at low pressure, followed by a relatively swift increase at higher pressure. The modification of the activated carbon DT0 by cold nitrogen plasma results in a slight increase in CO2 adsorption. The higher the adsorption temperature, the greater the difference between the initial carbon and the modified ones. This suggests the potential occurrence of chemical adsorption. Figure 6:2 FTIR spectra of pristine plasma samples (DT0) and those modified by N2 (DT0_1, DT0_2).