Hollow a-Fe₂O₃ Nanofibres for Solar Water Oxidation : Improving the Photoelectrochemical Performance by Formation of a-Fe₂O₃/ITO-Composite Photoanodes

Titelangaben

Einert, Marcus ; Ostermann, Rainer ; Weller, Tobias ; Zellmer, Sabrina ; Garnweitner, Georg ; Smarsly, Bernd M. ; Marschall, Roland:
Hollow a-Fe₂O₃ Nanofibres for Solar Water Oxidation : Improving the Photoelectrochemical Performance by Formation of a-Fe₂O₃/ITO-Composite Photoanodes.
In: Journal of Materials Chemistry A. Bd. 4 (2016) Heft 47 . - S. 18444-18456.
ISSN 2050-7496
DOI: https://doi.org/10.1039/c6ta06979g

Angaben zu Projekten

Abstract

We demonstrate the synthesis and photoelectrochemical performance of high-aspect ratio dense and hollow [small alpha]-Fe2O3 nanofibres, and the formation of core-shell-like [small alpha]-Fe2O3/indium-tin oxide (ITO) nanocomposites utilised as photoanode for solar water splitting. [small alpha]-Fe2O3 nanofibers were prepared via single-nozzle electrospinning technique using iron chloride (FeCl3) and poly(vinyl pyrrolidone) (PVP) as precursors followed by calcination. A new synthetic formation mechanism has been proposed taking into account the significance of three control parameters: (i) the iron precursor, (ii) the role of a co-solvent and (iii) the influence of the humidity on the tube evolution of [small alpha]-Fe2O3 nanotubes. Hollow [small alpha]-Fe2O3 fibres showed enhanced photocurrents and incident photon-to-current efficiency (IPCE) values compared to dense fibres, which are ascribed to the superior surface area of hollow fibres offering a good accessibility for the electrolyte and thus leading to improved mass transport. The photoelectrochemical properties of the [small alpha]-Fe2O3 nanofibers could be further enhanced by combination with highly crystalline, uniform ITO nanocrystals (O 10 nm), thus forming a core-shell-like [small alpha]-Fe2O3/ITO fibre nanocomposite. The doubled photocurrent of the [small alpha]-Fe2O3/ITO nanocomposite can most likely be assigned to the fast interfacial charge carrier exchange between the highly conductive ITO nanoparticles and [small alpha]-Fe2O3, thus inhibiting the recombination of the electron-hole pairs in the semiconductor by spatial separation.