Preparation and photoelectrochemical properties of functional carbon nanotubes and Ti co-doped Fe2O3 thin films

Functional carbon nanotubes (CNTs) were incorporated into Ti-doped Fe 2 O 3 thin films by a facile, one-step co-electrodeposition method. The films were characterized by X-ray diffraction, scanning electron microscopy, UV–visible absorption, and X-ray photoelectron spectroscopy. The introduction of CNTs results in a better absorption in visible region and greatly enhances the photoelectrochemical properties of the Ti–Fe 2 O 3 films. The improved photoelectrochemical properties of the CNTs and Ti co-doped Fe 2 O 3 films are due to the charge equilibration which interplays between the Ti–Fe 2 O 3 and CNTs. The effect of CNTs to mediate fast charge transfer and to retard charge recombination rate in the composites is also demonstrated by kinetics analysis and electrochemical impedance spectroscopy . The influence of different groups-modified CNTs and different content of CNTs was also studied. The highest photocurrent is 4.5 mA/cm 2 at 1.23 V (vs. RHE) obtained by incorporating 0.10 mg/mL amino-group modified CNTs in the Ti–Fe 2 O 3 film. The amino-functionalized CNTs doped film exhibits the highest photoelectric response compared with those doped by the pristine and acid-treated CNTs under the same conditions, which can be ascribed to the better hydrophilicity and dispersibility of the amino-functionalized CNTs.