## 3 Results  
The XRD patterns of TiO\({}_{2}\) and Ag/TiO\({}_{2}\) films with different sputtering power and times of Ag are shown in Figure 1a. The diffraction peaks at 25.1\({}^{\circ}\), 37.7\({}^{\circ}\), 47.9\({}^{\circ}\), 53.8\({}^{\circ}\), 55.0\({}^{\circ}\), and 62.5\({}^{\circ}\) correspond to the characteristic planes (101), (004), (200), (105), (211), and (204) planes of TiO\({}_{2}\) (JCPDS No. 21-1272), respectively [21; 22]. The results demonstrate that TiO\({}_{2}\) film has an anatase structure. The diffraction peaks at 38.0\({}^{\circ}\) and 44.1\({}^{\circ}\) correspond to the (111) and (200) crystal planes of Ag (JCPDS Card 01-1164), respectively. When the sputtering time of Ag is 100 s, with the increase in the sputtering power of Ag, the diffraction peak intensity of TiO\({}_{2}\) decreases gradually; the diffraction peak intensity of Ag also increases gradually, which indicates that the Ag deposited on the surface of TiO\({}_{2}\) film increases gradually with the increase in the sputtering power of Ag, shown in Figure 1a. The XRD patterns of Ag/TiO\({}_{2}\) thin films with a sputtering power of 5 W and different sputtering times for Ag are shown in Figure 1b. The diffraction peaks appear at 25.1\({}^{\circ}\) corresponding to the (101) plane of anatase TiO\({}_{2}\), at 38.0\({}^{\circ}\) and 44.1\({}^{\circ}\) corresponding to (111) and (200) crystal planes of Ag, respectively. With the increased sputtering time of Ag, the diffraction peak intensity of TiO\({}_{2}\) decreases gradually and the diffraction peak intensity of Ag increases gradually, as shown in Figure 1b. When the sputtering power and the sputtering time of Ag are 5 W and 150 s, respectively, the diffraction peak of TiO\({}_{2}\) is very weak. The intensity of the diffraction peak of Ag/TiO\({}_{2}\)-5 W-150 s at 38.0\({}^{\circ}\) and 44.1\({}^{\circ}\) is stronger than that of Ag/TiO\({}_{2}\)-15 W-100 s. These results show that the Ag deposition on the TiO\({}_{2}\) surface increases rapidly with increasing sputtering time. Figure 2 shows the surface morphologies of TiO\({}_{2}\) and Ag/TiO\({}_{2}\) films. It is possible to clearly observe the uniform small particles of TiO\({}_{2}\) deposited on the substrate in Figure 2a, which can make particles come into contact with the more suitable water and oxygen in the solution and produce more highly oxidized hydroxyl radicals; this leads to an increase in the photocatalytic activity of the catalysts [23]. When the sputtering power is 5 W, and the sputtering times are 50 s and 100 s, respectively, Ag particles are very small and evenly distributed on TiO\({}_{2}\) particles, as shown in Figure 2b,c. When the sputtering power is 5 W and the sputtering time is 150 s, it can be observed in Figure 2d that the distribution of Ag particles is uneven, and the magnitude of the Ag particles is much greater than that in Figure 2b and c. When the sputtering power is 10 W and the sputtering time is 100 s, the distribution of Ag particles is very uneven, as shown in Figure 2e. The distribution range of the Ag particle size is very wide and much wider than that shown in Figure 2d. The mass of Ag per unit area shown in Figure 2e is lower than that deposited at 5 W and 150 s as shown in Figure 2d. The results correspond to those of XRD in Figure 1. When the sputtering power is 15 W and the sputtering time is 100 s, the surface of the particles is smooth and somewhat round, and the Ag particles are shown to be uniformly and densely distributed  
Figure 1: XRD patterns of films (**a**) TiO\({}_{2}\) and Ag/TiO\({}_{2}\) with different sputtering powers of Ag (**b**) Ag/TiO\({}_{2}\) with different sputtering times of Ag. in Figure 2f. The experimental results indicate that sputtering power and time not only seriously affect the particle size but also affect the uniformity of particle distribution.