Photoelectrocatalytic properties and bactericidal activities of silver-treated carbon nanotube/titania composites

Two types of carbon nanotube/TiO2 and silver-treated carbon nanotube/TiO2 electrodes were prepared and characterized by X-ray diffraction, transmission and scanning electron microscopy, energy dispersive X-ray analysis, photoelectrocatalytic activity and antibacterial activity. The photoelectrocatalytic degradation of a methylene blue solution was attributed to the combined effects of the photo-degradation of TiO2, the electron assistance of carbon nanotube network and the enhancement of silver and was a function of the applied potential. The composites treated with silver showed enhanced photo-degradation of methylene blue, and the photoelectrocatalytic activity increased with increasing amount of silver. The silver-treated carbon nanotube/TiO2 prepared as bactericides have stronger antibacterial activity against Escherichia coli K-12 than standard ampicillin, tetracycline and carbon nanotube/TiO2 under sunlight or dark conditions. The presence of silver in the silver-treated carbon nanotube/TiO2 composites enhanced the inactivation of the E. coli K-12.