## 2 Results and Discussion  
### Characterization of Nanomaterial  
The FTIR spectra of the GW, Mg NPs, and Mg NP/GW nanocomposite are depicted in Figure 1. Notable bands were observed at 3409 cm\({}^{-1}\), 2928 cm\({}^{-1}\), 2375 cm\({}^{-1}\), 1634 cm\({}^{-1}\), and 1039 cm\({}^{-1}\) for the nanocomposite. In the Mg NP sample, the peak at 3409 cm\({}^{-1}\) may be attributed to the O-H stretching vibrations of adsorbed water molecules. The band at 2262 cm\({}^{-1}\) can be assigned to a nitrile group (C\(\equiv\)N), possibly originating from nitrate reduction during the synthesis processes [34; 35]. The sharp peak at 1634 cm\({}^{-1}\) can be attributed to the aromatic C=C stretching vibrations [36]. Additionally, the peaks at 1440 cm\({}^{-1}\) and 1062 cm\({}^{-1}\) may correspond to amide II and C-O single bond, respectively [37]. The peaks observed for the Mg NP/GW nanocomposite are a combination of the specific peaks seen in the GW and Mg NP samples. Furthermore, the low-intensity peaks at 926, 619, and 482 cm\({}^{-1}\) can be attributed to the metal oxide bond formation (M-O, M-O-M, O-M-O) at the surface of the magnesium nanoparticles. The hydrodynamic sizes of the produced samples are illustrated in Figure 2. The GW sample exhibited a broad peak with maximum intensity at approximately 400 nm. Following Mg precipitation in the Mg NP/GW nanocomposite, a slight shift towards larger sizes was observed, indicating an increase in hydrodynamic size after Mg precipitation. Conversely, the zero-valent Mg sample displayed a sharp peak at approximately 250 nm. Figure 1: FTIR spectra of GW, Mg NPs, and Mg NP/GW powder nanocomposite. Figure 2: Hydrodynamic size of GW, Mg NPs, and Mg NP/GW powder nanocomposite. Figure 3a depicts an SEM image of the GW sample, illustrating long fibrous materials typical of powdered plant-based samples. In Figure 3b, Mg nanoparticles are visible, exhibiting extensive aggregation and entanglement within the extracted matrix. Such aggregation is common in zero-valent metals synthesized through green methods, particularly when the metal concentration is significantly lower than that of the extract, as observed in this image. Figure 3c shows the composite where Mg nanoparticles are aggregated over the GW powder composed of fibrous material (Figure 3a). Figure 3d presents the EDX results for the Mg NP/GW powder nanocomposite. The composite primarily comprises carbon and oxygen originating from the GW powder. Additionally, other elements such as calcium, aluminum, and silicon are detected. The atomic percentage of magnesium in the composite is approximately 1% of the total elements present, while carbon and oxygen combined represent more than 96% of the total elements present. Figure 4a illustrates nitrogen adsorption-desorption isotherms classified as type IV. Among the samples, the Mg sample exhibited the highest surface area, measured at 42.2 m\({}^{2}\)/g as tabulated in Table 1.  
Figure 3: SEM images of (**a**) GW, (**b**) Mg NPs, (**c**) Mg NP/GW powder nanocomposite; (**d**) EDX of Mg NP/GW powder nanocomposite. Figure 4b displays the pore size distribution estimated from the nitrogen desorption branch of the isotherm. Notably, the Mg sample demonstrated the narrowest pore size distribution, with an average pore diameter of 0.5 nm (Table 1). In contrast, both the GW and composite samples exhibited similar wide pore size distributions, as depicted in Figure 4b. Figure 5 illustrates the XRD patterns of GW, Mg NPs, and Mg NP/GW powder nanocomposite. In the Mg sample, the main peak observed at 32\({}^{\circ}\) corresponds to the (100) plane family of Mg [38]. Importantly, no peaks corresponding to magnesium oxide (MgO) were detected, suggesting that any observed metal oxide bonds, such as Mg-O, Mg-O-Mg, and O-Mg-O, likely form on the surface of the Mg nanoparticles rather than in their core. This interpretation is supported by the absence of MgO peaks in the XRD diffractogram.