TiO2-based Nanocolumn Arrays for Photoelectrochemical Water Splitting: Electrochemical Characterization

abstrakt

angličtina

Titanium dioxide is a widely investigated material for numerous applications, including photoelectrochemical (PEC) water splitting as the way to utilize solar energy for hydrogen production. Nanostructuring of TiO2, in the form of nanocolumn arrays, may lead to substantial improvements of the PEC performance owing to an increase in the surface-to-volume ratio combined with shorter charge transport pathways. On the other hand, too small nanostructures may reside in flat-band condition, having no depletion layer crucial for effective charge carrier separation. Thus, an adjusted size of the nanocolumns having a depletion layer of optimum thickness, occupying a big portion of the column itself, may lead to charge separation taking place in a substantial portion of the nanocolumn volume, increasing the PEC response. Therefore, in this work, we study various types of morphology, crystallinity, oxygen vacancy concentration, and doping level in the TiO2 nanocolumn arrays in order to achieve a depletion layer taking up substantial volume of the nanocolumns. To evaluate these semiconductive properties, we perform electrochemical impedance spectroscopy (EIS) measurements at various voltages in the dark on differently fabricated and modified TiO2 surfaces.

titania nanorods, electrochemical impedance spectroscopy, Mott-Schottky analysis

LEDNICKÝ, T.; MOZALEV, A.; BENDOVÁ, M.

5. 9. 2016

nanoGe

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