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BENDOVÁ, M. GISPERT-GUIRADO, F. HASSEL, A. LLOBET, E. MOZALEV, A.
Originální název
Solar water splitting on porous-alumina-assisted TiO2-doped WOx nanorod photoanodes: Paradoxes and challenges
Typ
článek v časopise ve Web of Science, Jimp
Jazyk
angličtina
Originální abstrakt
Arrays of self-organized WO3-based semiconductor nanorods are prepared from a thin W layer, W/Ti bilayer (tungsten-on-titanium), and W-10at.%Ti alloy layer via the porous-anodic-alumina (PAA)-assisted anodization at various conditions to address the radius/length ratio of~13/130 and ~70/700 nm (respectively ‘small’ and ‘big’ nanorods). Doping the WO3 nanorods with TiO2 was achieved, for the first time, simply by anodizing the W/Ti and W-10at.%Ti layers through the alumina nanopores. The post-anodizing treatments combined PAA dissolution with annealing in air and vacuum at 500–550 °C to alter the film composition, crystal structure, and electrical properties. The air-annealed big nanorods comprising monoclinic and triclinic WO3 crystal phases reveal their superior performance in photoelectrochemical (PEC) water splitting, showing a low onset potential (0.5 VRHE) and a competitive value of photocurrent (15.5 mA·cm−2) in 0.1 mol·dm−3 Na2SO4 solution (pH 5.0) under chopped illumination at a single wavelength of 405 nm, 1 W·cm−2, with no sign of photocorrosion. Paradoxically, the presence of monoclinic WO2.9 phase in the vacuum-annealed nanorods worsens the PEC behavior and stimulates the peroxo-assisted dissolution. Unexpectedly, electrochemically doping both the WO3 and WO2.9 big nanorods with TiO2 causes the photocurrent to decrease dramatically. An advanced approach developed for modeling charge transport processes in the PAA-assisted WOx nanorods predicts a 7-fold further rise in the solar current should the big nanorods grow longer (1.5 μm) and wider (300 nm) to absorb a bigger portion of light and support a thicker depletion layer, without, however, getting fully depleted, which is the case of the small nanorods.
Klíčová slova
anodizing; porous anodic alumina; tungsten oxide; titanium oxide; nanorods; photoelectrochemical water splitting
Autoři
BENDOVÁ, M.; GISPERT-GUIRADO, F.; HASSEL, A.; LLOBET, E.; MOZALEV, A.
Vydáno
23. 1. 2017
Nakladatel
Elsevier B.V.
Místo
Amsterdam, The Netherlands
ISSN
2211-2855
Periodikum
Nano Energy
Číslo
33
Stát
Spojené státy americké
Strany od
72
Strany do
87
Strany počet
16
URL
http://dx.doi.org/10.1016/j.nanoen.2017.01.029
BibTex
@article{BUT132011, author="Mária {Bendová} and Francesc {Gispert-Guirado} and Achim Walter {Hassel} and Eduard {Llobet} and Alexander {Mozalev}", title="Solar water splitting on porous-alumina-assisted TiO2-doped WOx nanorod photoanodes: Paradoxes and challenges", journal="Nano Energy", year="2017", number="33", pages="72--87", doi="10.1016/j.nanoen.2017.01.029", issn="2211-2855", url="http://dx.doi.org/10.1016/j.nanoen.2017.01.029" }