###### Abstract  
Ag and Au nanoparticles (NPs) were decorated on the surface of TiO\({}_{2}\) membranes by two methods, i.e., hydrothermal synthesis and photoreduction. The size of Ag and Au NPs on the surface of TiO\({}_{2}\) membranes was dependent on the method of preparation and varied from 2 nm-10 nm. The photocatalytic performance of the TiO\({}_{2}\) particle, TiO\({}_{2}\) membrane and the Ag/Au-decorated TiO\({}_{2}\) membrane was tested for the catalytic degradation of Rhodamine B (RhB) and _Escherichia coli_ (_E. coli_) under irradiation of visible light. The experiment results showed that both Ag- and Au-decorated TiO\({}_{2}\) membranes exhibited excellent photocatalytic activity in the visible light region. Among the prepared materials, Ag-decorated TiO\({}_{2}\) membranes prepared by photoreduction showed the highest activity, which could be attributed to the local surface plasmon resonance (LSPR) effect of the noble metal. TiO\({}_{2}\) membrane; Ag decoration; photocatalyst; visible light irradiation; _Escherichia coli_  
In recent years, many thin film materials, including carbon film, graphene and thin SnO\({}_{2}\) membranes, have been studied and have shown excellent physical and chemical properties [1; 2; 3]. Various TiO\({}_{2}\) nanomaterials have also been reported, such as TiO\({}_{2}\) nanopowders, nanowires, nanotubes, nanoflowers, etc. [4; 5; 6]. Among them, TiO\({}_{2}\) membrane have gained considerable attention due to their outstanding catalytic performance, which could be attributed to the large surface area and low thickness of the material [7; 8]. TiO\({}_{2}\) nanoparticles (NPs) with a large specific area have higher photocatalytic efficiency because the photocatalytic process occurs on the surface. High photocatalytic efficiency is the main evaluation method for photocatalysts, which is important to degrade organics in short time periods [9; 10]. According to the research, photocatalysts with low photocatalytic efficiency degraded organics within a couple of hours, such as nitrogen-doped TiO\({}_{2}\) thin film [11], TiO\({}_{2}\) nanotubes [12] and BiOCl nanowire arrays [13]; high photocatalytic efficiency like that of BiOCl membranes could completely degrade RhB within 2 min under UV light [14]. Further modification of TiO\({}_{2}\) can improve its response to visible light, inhibit the recombination of photogenerated carriers and, consequently, enhance the photocatalytic performance. Various materials, including metals (Au, Ag, Pt, Cu), non-metals (C, N, S), metal oxides (WO\({}_{3}\), Fe\({}_{2}\)O\({}_{3}\), SiO\({}_{2}\)), etc., have been used to dope TiO\({}_{2}\)[8; 15; 16; 17]. These doping materials can produce vacancies and interstitial or substitutional defects that change the photocatalytic properties of TiO\({}_{2}\). The band gap of TiO\({}_{2}\) is narrowed notably after doping with noble metals (Au, Ag, Pt) [18]. Because the noble metals have lower Fermi levels than TiO\({}_{2}\), the photogenerated electrons of the conduction band will not recombine with the holes, but instead transfer to the noble metal particles on the surface of TiO\({}_{2}\)[19; 20; 21; 22]. Hence, the photogenerated electrons and holes are effectively separated, and the photocatalytic activity is improved [23; 24; 25]. Moreover, the noble metal NPs can more easily attract organic molecules than semiconductors. Therefore, the noble metal NPs play the role of the electron carrier in the system of TiO\({}_{2}\) doped with noble metals, which is an effective method to improve the photocatalytic properties of TiO\({}_{2}\). Herein, we report a TiO\({}_{2}\) membrane decorated with Ag and Au NPs, which exhibited extremely high catalytic efficiency. The TiO\({}_{2}\) membrane was prepared by a hydrothermal method [26]. A certain amount (8 mL) of TiCl\({}_{3}\) was mixed with ethylene glycol (30 mL), and the mixture was stirred for 7 h at room temperature until the reaction completed.