Enhanced photocatalytic and photoelectrochemical activity via sensitization and doping of novel TiO2 nanowire/nanoleaf arrays: dual synergistic effects between TiO2–N and CdS–Mn

Abstract

We report the synthesis and photoelectrochemical properties of novel one-/two-dimensional hybrid TiO₂ nanostructures simultaneously doped with nitrogen and sensitized with Mn-doped CdS quantum dots. These co-doped novel nanocomposite structures displayed a significantly enhanced photoresponse compared with a single doping or sensitization strategy. This enhancement was attributed to the double synergistic effect of N doping of TiO₂, which facilitated hole transfer/transport from the sensitizers to TiO₂ via oxygen vacancy states mediated by the N and Mn doping that created electronic states in the CdS mid-gap region, thus altering the charge separation and recombination dynamics in addition to tuning the optical properties. Photoluminescence spectrometry and monitoring of the yield of active hydroxyl radicals on irradiation supported the presence of this double synergistic effect.