Solar water splitting on porous-alumina-assisted TiO2-doped WOx nanorod photoanodes: Paradoxes and challenges

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216305%3A26620%2F17%3APU122172" target="_blank" >RIV/00216305:26620/17:PU122172 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1016/j.nanoen.2017.01.029" target="_blank" >http://dx.doi.org/10.1016/j.nanoen.2017.01.029</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1016/j.nanoen.2017.01.029" target="_blank" >10.1016/j.nanoen.2017.01.029</a>

Result language

angličtina

Original language name

Solar water splitting on porous-alumina-assisted TiO2-doped WOx nanorod photoanodes: Paradoxes and challenges

Original language description

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.

Czech name

—

Czech description

—

Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

—

OECD FORD branch

10405 - Electrochemistry (dry cells, batteries, fuel cells, corrosion metals, electrolysis)

Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2017

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Nano Energy

ISSN

2211-2855

e-ISSN

2211-3282

Volume of the periodical

neuveden

Issue of the periodical within the volume

33

Country of publishing house

US - UNITED STATES

Number of pages

16

Pages from-to

72-87

UT code for WoS article

000397314200009

EID of the result in the Scopus database

2-s2.0-85010216155