## 3 Results and Discussion
After three cycles of the experiment, the recovered samples underwent a self-cleaning treatment. Subsequently, the photocatalytic efficiency experienced a resurgence in the fourth cycle. It was found that although the addition of Na\({}_{2}\)SO\({}_{4}\) inhibited the efficiency of FS-FT (0.36 g) in degrading MO, the inhibitory effect was not very significant; it still had strong photocatalytic activity. XPS spectra were used to research the photocatalyst electronic characteristics and elemental composition in Figure 8. All core-level XPS spectra were calibrated using the adventitious carbon C 1s peak at 284.8 eV for charge correction. Ti 2p: Figure 8a,b show the XPS spectra of FS-FT (0 g) and FS-FT (0.36 g) before photodegradation, respectively. Figure 8c,d show the high-resolution XPS spectra of FS-FT (0.36 g, MO) after photodegradation in pure MO solution and FS-FT (0.36 g, MO-Na\({}_{2}\)SO\({}_{4}\)) after photodegradation in MO-Na\({}_{2}\)SO\({}_{4}\)-blended solution, respectively. In Figure 8a, the spin-orbit splitting of Ti\({}^{4+}\) results in two peaks: Ti\({}^{4+}\) 2p\({}_{3/2}\) (458.6 eV) and Ti\({}^{4+}\) 2p\({}_{1/2}\) (464.3 eV) [28]. Figure 8b-d show Ti 2p XPS spectra of samples doped with Fe\({}^{3+}\) with two peaks, respectively. The Ti 2p doublet was observed at binding energies of 458.7 eV (2p\({}_{3/2}\)) and 464.4 eV (2p\({}_{1/2}\)), exhibiting a spin-orbit splitting of 5.7 eV. This finding aligns with previously reported data in the literature [29]. The Ti 2p peaks exhibited a shift toward \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Material**} & **Initial** & **Amount of Catalyst** & **(MO) Degradation Time (min) and Degradation Rate** & **(MO-Na\({}_{2}\)SO\({}_{4}\))** & **Cyclic Average** \\  & **Concentration of MO (mg/L)** & **E** **mL (mg)** & **Degradation Rate** & **(min) and Degradation Rate** & **(min) and Degradation Rate** \\ \hline ATT-SnO\({}_{2}\)-TiO\({}_{2}\) & 20 & 1 & 30 (99\%) & none & none \\ ZnO/TiO\({}_{2}\) & 16 & 0.3 & 100 (98\%) & none & none \\ Pt-TiO\({}_{2}\)/zeolite & 20 & 2 & 90 (99\%) & none & none \\ FS-FT (0 g) & 10 & 2 & 25 (90.25\%) & 25 (92.38\%) & 86.08\% \\ FS-FT (0.36 g) & 10 & 2 & 25 (99\%) & 25 (97.16\%) & 96.63\% \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The photocatalytic effectiveness of the materials. Figure 7: The degradation efficiency in MO-Na\({}_{2}\)SO\({}_{4}\)-blended solution using (a) FS-FT (0 g); (b) FS-FT (0.36 g) for five cycles. a higher binding energy, signifying the successful integration of Fe\({}^{3+}\) ions into the TiO\({}_{2}\) lattice [29; 30]. O 1s: Figure 8e-h show the XPS spectra of O 1s for FS-FT (0 g), FS-FT (0.36 g), FS-FT (0.36 g, MO), and FS-FT (0.36 g, MO-Na\({}_{2}\)SO\({}_{4}\)), respectively. There are three peaks for both undoped and Fe-doped samples. O1s is in Ti-O at 529.6 eV for FS-FT (0 g) in Figure 8e, 529.8 eV for FS-FT (0.36 g) in Figure 8f, 529.8 eV for FT (0.36 g, MO) in Figure 8g, and 529.8 eV for FS-FT (0.36 g, MO-Na\({}_{2}\)SO\({}_{4}\)) in Figure 8h, respectively. O1s is in Fe-O at 530.4 eVfor FS-FT (0 g) in Figure 8e, 530.64 eV for FS-FT (0.36 g) in Figure 8f, 530.64 eV for FT (0.36 g, MO) in Figure 8g, and 530.64 eV for FS-FT (0.36 g, MO-Na\({}_{2}\)SO\({}_{4}\)) in Figure 8h, respectively. This is because some Fe\({}^{3+}\) ions replace Ti\({}^{4+}\) ions, leading to a shift in the peak. Peaks at 532.5 eV (Figure 8e-h) are linked to oxygen atoms bound to O in O-H [29; 31]. Fe 2p: In Figure 8i, the XPS spectrum of FS-FT (0 g) before photodegradation is due to the fact that the XPS instrument only scans the surface of the sample, the Fe element is located in the core of the core-shell structure, and the scanning data have poor signal and more noise. Figure 8j shows the XPS spectra of Fe 2p for FS-FT (0.36 g) before photodegradation.