###### Abstract
Then, doubly-distilled water (1 mL) was added, and the mixture was transferred into a stainless steel reactor and kept at 150 \({}^{\circ}\)C for 4 h. The products were separated by centrifugation at 16,000 rpm, washed with ethanol three times and dried in a vacuum at 50 \({}^{\circ}\)C for 48 h. TiO\({}_{2}\) membrane was decorated with Ag and Au NPs by the hydrothermal and photoreduction methods, respectively. The mixture of the TiO\({}_{2}\) membrane (0.4 mg) and AgNO\({}_{3}\) or HAuCl\({}_{4}\) (0.015 mol/L, 0.4 mL) was processed by 365-nm UV light or hydrothermal reaction (180 \({}^{\circ}\)C, 6 h). The final products were centrifuged at 10,000 rpm, washed with doubly-distilled water three times and dried in a vacuum at 50 \({}^{\circ}\)C for 24 h. The sample descriptions are given in Table 1.  
TiO\({}_{2}\) membranes decorated with Ag and Au NPs were observed and characterized by transmission electron microscope (TEM, Talos F200S, Thermo fisher, Waltham, MA, USA) and X-ray diffraction (XRD, PHILIPS P W 3O4O/60X\({}^{\prime}\)PertPRO, Amsterdam, The Netherlands). Scanning electron microscope energy dispersive spectrometer (SEM EDS, JSM-7500F, JEOL Ltd., Tokyo, Japan) analysis showed the real composition of the prepared samples, as given in Table 1. Ultraviolet-visible light (UV-Vis) diffuse reflectance spectroscopy was measured on a Perkin Elmer UV-Vis spectrometer (Lambda 750 S, Perkin Elmer, Waltham, MA, USA) equipped with a Labsphere RSA-PE-20 integration sphere. The electrochemical behaviors of the TiO2 membranes, SAg and SAu, were examined by electrochemical impedance spectroscopy (EIS, RST5200F, Shiruisi Instrument, Zhengzhou, China). The photocatalytic performance of the TiO\({}_{2}\) membranes, S\({}_{\text{Ag}}\) and S\({}_{\text{Au}}\), was evaluated by the degradation reaction of Rhodamine B (RhB). A Xe lamp with optical filters (14 V, 14-21 A, visible light) was used as the light source, and the distance between the lamp and the interface of the solution was 12 cm (0.1 W/m\({}^{2}\)). The test was carried out by adding the prepared photocatalyst (0.4 mg) to the solution of RhB (5 mg/L, 250 mL) and measuring the absorbance at 552 nm (i.e., the maximum absorption wavelength of RhB) by UV-visible spectrophotometry every 5 min. The concentration of RhB in the solution was calculated from the absorbance, and the photocatalytic degradation efficiency was calculated as follows:  
\[\eta=\frac{C_{0}-C_{t}}{C_{0}} \tag{1}\]  
where \(C_{0}\) is the initial concentration of RhB and \(C_{t}\) is the concentration of RhB after an irradiation time of \(t\). _Escherichia coli_ (_E. coli_) cells were treated by S\({}_{\text{Ag}}\) under visible light irradiation (0.1 W/m\({}^{2}\)) for 10 min. Then, the morphology of the native and treated _E. coli_ cells was examined by SEM. The cells were fixed according to the standard protocol by reduction with glutaraldehyde and oxidation with OsO\({}_{4}\), then dehydrated stepwise with ethanol of increasing concentration (50-100%). \begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Name** & **Sample Description** & **Process Method** & **Ti (At\%)** & **Ag (At\%)** & **Au (At\%)** \\ \hline S\({}_{0}\) & TiO\({}_{2}\) membrane & & - & - & - \\ S\({}_{\text{Ag-UV}}\) & TiO\({}_{2}\) membrane with Ag & UV & 48.2 & 1.1 & – \\ S\({}_{\text{Ag-HY}}\) & TiO\({}_{2}\) membrane with Ag & hydrothermal reaction & 47.7 & 2.0 & – \\ SA\({}_{\text{Au-UV}}\) & TiO\({}_{2}\) membrane with Au & UV & 48.1 & – & 1.2 \\ SA\({}_{\text{Au-HY}}\) & TiO\({}_{2}\) membrane with Au & hydrothermal reaction & 47.6 & – & 2.3 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Processes for TiO\({}_{2}\) membranes. The prepared TiO\({}_{2}\) membrane was decorated with Ag/Au NPs by either hydrothermal synthesis or photoreduction. The morphology and structure of the resulting material were observed and characterized by TEM. Figure 1 shows the diameter histogram and the TEM images of the S\({}_{\text{Ag}}\) and S\({}_{\text{Au}}\) samples prepared under different conditions.