Template-induced synthesis and superior antibacterial activity of hierarchical Ag/TiO2 compositesElectronic supplementary information (ESI) available: TG curve of Ag2CO3/TiO2·xH2O, XRD patterns and SEM image of as-prepared products with different concentration of AgNO3, EDX image of Ag/TiO2 composite, and MICs of Ag/TiO2 composite against (a) E. coli (b) S. aureus. See DOI: 10.1039/c5ra16092h

• Main Authors: Cheng, Hang, Ye, Junwei, Sun, Yuan, Yuan, Wenjie, Tian, Junying, Bogale, Raji Feyisa, Tian, Peng, Ning, Guiling
• Format: Article
• Language: English
• ISSN: 2046-2069
• DOI: 10.1039/c5ra16092h

Hierarchical Ag/TiO 2 composites were successfully synthesized via a hydrated magnesium carbonate hydroxide template-induced route. The prepared composites possess hierarchical flower-like structure and high Brunauer-Emmett-Teller (BET) surface area of 131.9 m 2 g −1 . The amount of silver nanoparticles (Ag NPs) with diameter of 20-40 nm in the composite can be adjusted by the concentration of AgNO 3 solution. The antibacterial potency of Ag/TiO 2 composites was investigated against Gram-negative bacteria, Escherichia coli ( E. coli ) and Gram-positive bacteria, Staphylococcus aureus ( S. aureus ) by determining the minimal inhibitory concentration (MIC), the growth curve of bacteria and using the zone of inhibition technique. The synergistic effect of Ag NPs and TiO 2 lead to superior and long-term antimicrobial activities of the composites with a bacteriostatic rate as high as 99.99%. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and the fluorescence microscopy showed the integrity of membrane of the bacteria was destroyed by adding a given amount of composites resulting in cell death as well. The mechanism of antibacterial activity of composites was also taken into account by using TEM, inductively coupled plasma atomic emission spectrometry (ICP-AES), ultraviolet visible diffuse reflectance spectroscopy and fluorescent microscopy. Hierarchical Ag/TiO 2 composites were successfully synthesized via hydrated magnesium carbonate hydroxide template-induced route, which exhibit superior and long-term antimicrobial activity.