Photocatalytic and antibacterial activity of B/N/Ag co-doped CNT–TiO2 composite films

Abstract

Thin films of TiO2 and B/N/Ag co-doped car- bon nanotube (CNT)-TiO2 (Ag/B/N-CNT-TiO2) com- posite on top of glass substrates have been successfully prepared by a simple sol-gel drop coating route. The films were characterized by X-ray diffraction (XRD) and UV- Vis spectroscopy. XRD patterns of TiO2, CNT-TiO2 and co-doped TiO2 composite films were shown single phase of anatase. The UV-Vis absorption spectra showed absorption edge shifted to visible light region after doping Ag/B/N in TiO2. The photocatalytic properties of Ag/B/N-CNT-TiO2 thin films were evaluated by degradation of methylene blue under visible light irradiation. It has been found that photocatalytic efficiency was significantly improved when TiO2 is subjected to modify by using Ag, B, N and CNT. The highest photocatalytic activity has been shown by 2 %B/5 %N-CNT-TiO2 with 58 % efficiency whereas the efficiency was only 17 % for pure TiO2 film. The ex- perimental photodegradation data were well fitted by zero- order, first-order and modified Freundlich kinetic models. The antimicrobial activities of the prepared composite thin films have also been tested using bacteria Escherichia coli (E. coli). The composite Ag-TiO2 and 2 %B/5 %N/ 2 %Ag-CNT-TiO2 showed higher antimicrobial activity than B/N-CNT-TiO2. All of the thin films have been used in many times for the degradation measurement and an- tibacterial studies.