## 3 Results
By comparing samples with different sputtering powers and sputtering times, it can be found that Ag particles sputtered at 5 W and 50 s (Ag/TiO\({}_{2}\)-5 W-50 s) are more uniform and smaller in size, which can reduce the recombination rate of photogenic electron-hole pairs and enhance the catalytic productivity of the photocatalyst [15; 16]. Figure 2g shows the cross-section morphologies of TiO\({}_{2}\). The thickness of the film is about 235 nm. It was calculated that the Ag particle sizes of Ag/TiO\({}_{2}\)-5 W-50 s, Ag/TiO\({}_{2}\)-5 W-100 s, Ag/TiO\({}_{2}\)-5 W-150 s, Ag/TiO\({}_{2}\)-100 s, and Ag/TiO\({}_{2}\)-15 W-100 s are 44 nm, 99 nm, 65 nm, 108 nm, and 92 nm, respectively. The results suggest that the Ag particles sputtered at 5 W and 50 s favored the photocatalytic degradation of MO. This is because small isolation facilitates the separation of photogenic charge carriers [24]. To obtain high-quality signals of chemical compositions, the sample of Ag/TiO\({}_{2}\)-5 W-150 s was measured using EDS, as shown in Figure 2h-k. The EDS analysis was performed to confirm the presence of different elements in the composite. It is possible to observe that the material contains three elements, Ti, Ag, and O, which are uniformly distributed in Figure 2h-k. The EDS point analysis is shown in Figure 2l; Ti, Ag, and O are detected. Other elements may come from pollution and substrates. Figure 2: SEM images and mapping of elemental analyses of TiO\({}_{2}\) (**a**), Ag/TiO\({}_{2}\) (**b**), Ag/TiO\({}_{2}\)-5 W-50 s, (**c**) Ag/TiO\({}_{2}\)-5 W-100 s, (**d**) Ag/TiO\({}_{2}\)-5 W-150 s, (**e**) Ag/TiO\({}_{2}\)-10 W-100 s, and (**f**) Ag/TiO\({}_{2}\)-15 W-100 s; (**g**) cross-section of TiO\({}_{2}\); (**h–k**) EDS mappings of Ag/TiO\({}_{2}\)-5 W-150 s; and (**l**) EDS point analysis of Ag/TiO\({}_{2}\)-5 W-150 s films. The 3D surface topographies and roughness of films are studied via AFM in Figure 3 and Table 1. It is seen that the 3D surface topographies of all samples are columnar structures. Figure 3a shows the 3D surface topography of TiO\({}_{2}\); it can be seen that the TiO\({}_{2}\) nanoparticles are uniformly dispersed on the entire substrate surface. When Ag with a power of 5 W and a sputtering time of 50 s is used for the surface modification of TiO\({}_{2}\), the average diameter of the columnar structure is the smallest in Figure 3b. The maximum constructive height is 102.26 nm corresponding to the Ag/TiO\({}_{2}\)-5 W-100 s film in Figure 3c. With the increase in the sputtering time of Ag, the constitutive height of the Ag/TiO\({}_{2}\)-5 W-50 s film as shown in Figure 3b first increases from 41.27 nm to 102.26 nm of Ag/TiO\({}_{2}\)-5 W-100 s film, shown in Figure 3c, and then decreases to 80.42 nm of the Ag/TiO\({}_{2}\)-5 W-150 s film, shown in Figure 3d. With the increase in the sputtering power of Ag, the constitutive height of Ag/TiO\({}_{2}\)-10 W-100 s film shown in Figure 3e first decreases to 63.29 nm from 102.26 nm of Ag/TiO\({}_{2}\)-5 W-100 s, shown in Figure 3c, and then increases to 70.92 nm of Ag/TiO\({}_{2}\)-15 W-100 s film, as shown in Figure 3f. Figure 3: A set of 3D diagrams of the following films: (**a**) TiO\({}_{2}\), (**b**) Ag/TiO\({}_{2}\)-5 W-50 s, (**c**) Ag/TiO\({}_{2}\)-5 W-100 s, (**d**) Ag/TiO\({}_{2}\)-5 W-150 s, (**e**) Ag/TiO\({}_{2}\)-10 W-100 s, and (**f**) Ag/TiO\({}_{2}\)-15 W-100 s.  
The surface roughness is shown in Table 1. The maximum surface roughness is 7.534 nm, corresponding to the Ag/TiO\({}_{2}\)-5 W-100 s film detailed in Table 1. With the increase in the sputtering time of Ag, the surface roughness of the film increases from 2.203 nm to 7.534 nm and then decreases from 7.534 nm to 3.118 nm. With the increase in the sputtering power of Ag, the surface roughness of the film decreases from 7.534 nm to 4.723 nm and then increases from 4.723 nm to 7.082 nm. The results indicate that the sputtering power and time of Ag have an impact on the surface roughness of the film. Figure 4a-c show the UV-Vis DRS of the samples.