Photoelectrochemical characterization of ITO/TiO2 electrodes obtained by cathodic electrodeposition from aqueous solution

Abstract

In the present work, the photoelectrochemical characterization of ITO/TiO 2 electrodes electrosynthesized at two distinct TiO 2 film charges (0.35 and 1.00 C) was performed. Scanning electron microscopy presented a globular-like nanostructure and a typical morphology that are dependent on the growing charge, where the photoelectrode synthesized at 0.35 C presented a more homogeneous morphology. Such dependence was also observed at the photoelectrochemical response, once the photoactivity for the photoelectrode synthesized at 0.35 C was better than the photoelectrode synthesized at 1.00 C, which was explained by the surface recombination process and the electron lifetime. In order to explore the charge-transfer process and the displacement of the quasi-Fermi level upon illumination, electrochemical impedance spectroscopy (EIS) was performed at distinct applied potentials. EIS results corroborate the previous results, presenting a higher charge-transfer resistance and a lower chemical capacitance for the 1.00 C electrode film, the last one in accordance with the open-circuit voltage decay.

Enhanced Photoelectrochemical Activity of TiO2 Nanotubes Decorated with Lanthanide Ions for Hydrogen Production

“…Lastly, the photogeneration of electrons did not occur when the light was blocked after 120 s; however, the electrons accumulated on the photoelectrode were recombined and the potential increased in the positive direction. Thus, the OCP of the photocatalysts reflects the photogenerated charge carrier density [33]. Figure 7a shows that doping with lanthanides results in higher OCP values than that of pure TNT, regardless of the type (Table 3).…”