In-situ manganese doping of TiO2 nanostructures via single-step electrochemical anodizing of titanium in an electrolyte containing potassium permanganate: A good visible-light photocatalyst

It is desirable to induce remarkable red-shift in the optical absorption edges of TiO2 so that this class of low-cost materials can be used as optimum photocatalysts beyond the ultraviolet range. This work reports on the room-temperature electrochemical fabrication of manganese-doped TiO2 nanotubes (MnTNT) and the investigation of their optical property and photocatalytic activity. TiO2 nanotubes (TNT) were doped with different concentrations of manganese and prepared nanostructures have been characterized using different techniques for analyzing their structure, morphology, composition, band gap and optical absorption property. Characterization of the as-prepared samples indicated that dopant concentration in anodizing solution significantly influenced the morphology, structure, photoabsorption and photocatalytic activity of fabricated films. The optical absorption range of TiO2 film gradually expands and shifts to the red with increasing dosages and band gap of the TiO2 films were reduced. Moreover, the photocatalytic activity of the TiO2 films for removal of methylene blue was enhanced by doping with an appropriate amount of manganese. The sample MnTNT4 exhibited better photocatalytic activity than the undoped TNT and MnTNT fabricated using other manganese concentrations. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.