# Enhancing Methyl Orange Degradation with Laser-Generated ZnO and Ce-Doped ZnO Nanoparticles
## 3 Results and Discussion
### Characterizations
#### 3.2.2 FESEM and EDX Analysis  
The prepared undoped ZnO and 1% Ce/ZnO NP powder morphologies were investigated using FESEM and EDX analysis. In Figure 4, the morphology of the undoped ZnO NPs is highlighted, showing their hexagonal shape with a closely packed arrangement. These NPs were prepared using a CO\({}_{2}\) laser and exhibited diameters ranging from 26 to 350 nm, consistent with previous reports [32]. Furthermore, the FESEM analysis provided evidence of the successful incorporation of Ce into the ZnO powder. Using a high-power CW CO\({}_{2}\) laser with an effective Ce source formed 3D spherical nanostructures, as depicted in Figure 4e,f. These 3D sphere-like NPs were observed to adhere to one another and exhibited a diameter range of 3.2-127 nm. To quantify the particle size, average diameter, and diameter range, a thousand particles were selected and measured using ImageJ software (Image) 1.46, Java 1.6.0_20 (64-bit)) (refer to Table S3). Notably,  
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{8}{c}{**XRD**} \\ \cline{2-9}  & \multicolumn{4}{c}{**Wurtzite Hexagonal ZnO Phase**} & \multirow{2}{*}{**Cubic-Structured CeO\({}_{2}\) Phase**} \\ \cline{2-9}  & \(a\) (nm)\({}_{100}\) & \(c\) (nm)\({}_{022}\) & \(c\)/\(a\) & \(D\) (nm)\({}_{ave}\) & \(X_{\mathbf{c002}}\) & \multicolumn{2}{c}{**X\({}_{\mathbf{c002}}\)**} \\ \hline Undoped ZnO & 0.3238 & 0.5221 & 1.612 & 117 & 1.493 & \(a\) (nm)\({}_{111}\) & \(c\)/\(a\) & \(D\) (nm)\({}_{ave}\) \\ \hline
1\% Ce-doped ZnO & 0.31857 & 0.5229 & 1.641 & 90 & 0.443 & 0.5356 & 1 & 19 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Cell parameters a and c, average crystalline size \(D\), and degree of crystallinity \(X_{c}\).  
Figure 3: XRD patterns of (**a**) undoped ZnO with standard XRD JCPDS No. 01-080-0075 data of ZnO and for peak comparison and (**b**) 1% Ce-ZnO nanoparticles with ZnO XRD JCPDS No. 01-080-0075 and CeO\({}_{2}\) JCPDS No. 03-065-2975 data for peak comparison.  
the choice of Ce source, specifically Ce (NO\({}_{3}\))\({}_{3}\). 6H\({}_{2}\)O, significantly impacted the final product's morphology [33]. Additionally, the morphology and crystal structure of the end products were directly influenced by factors such as the CO\({}_{2}\) laser power, irradiation time, and wavelength.  
EDX analysis in Figure 4d revealed numerous well-defined peaks corresponding to Zn, Ce, and O, indicating their uniform distribution throughout the sample area. This observation provided strong evidence of the successful doping of Ce into the ZnO matrix. Significantly, the intensity of the Ce element surpassed that of Zn, indicating an enrichment  
Figure 4: (a) EDX analysis depicting the chemical composition of undoped ZnO NP powder. (b) FESEM micrograph illustrating the morphology of the sample, with a scale bar of 500 nm. (c) A magnified image of 234 particles is enclosed within the red box. (d) EDX analysis of the elemental composition, and (e,f) FESEM image and analysis displaying the elemental composition and the morphology of the 3D sphere-like nanoparticle powder, which is doped with 1% Ce-doped ZnO.  
of Ce within the NPs compared to its surroundings. The atomic ratio [Ce]/[Zn] was calculated to be 1.16%, which closely matches the theoretical doping level of 1% [30; 34]. Moreover, the absence of any foreign elements detected in the synthesized samples further confirms the successful synthesis of Ce-doped ZnO. However, it was observed through EDX that an increase in oxygen vacancies in the 1% Ce/ZnO NPs also influenced the photocatalytic activity [11].