Band gap narrowing of titanium dioxide (TiO2) nanocrystals by electrochemically active biofilms and their visible light activity

Abstract

We report a simple biogenic-route to narrow the band gap of TiO2 nanocrystals for visible light application by offering a greener method. When an electrochemically active biofilm (EAB) was challenged with a solution of Degussa-TiO2 using sodium acetate as the electron donor, greyish blue-colored TiO2 nanocrystals were obtained. A band gap study showed that the band gap of the modified TiO2 nanocrystals was significantly reduced (Eg = 2.85 eV) compared to the unmodified white Degussa TiO2 (Eg = 3.10 eV). © 2013 The Royal Society of Chemistry.