Photoelectrochemical water splitting with porous α-Fe2O3 thin films prepared from Fe/Fe-oxide nanoparticles

S. Emin, M. De Respinis, T. Mavrič, B. Dam, M Valant, W. A. Smith

Research output: Contribution to journalArticleScientificpeer-review

21 Citations (Scopus)

Abstract

We report on the photoelectrochemical (PEC) performance related to water oxidation of porous hematite (α-Fe2O3) thin films, which were prepared by spin coating of colloidal core/shell Fe/Fe-oxide nanoparticles (NPs) on fluorine-doped SnO2 (FTO) substrates. Oxidation of the obtained Fe/Fe-oxide films at 600 °C, 700 °C, and 800 °C in air yielded porous α-Fe2O3 thin films. The advantage of using Fe/Fe-oxide NPs is that they form stable suspensions in organic solvents and are suitable for spin coating. The highest photocurrent density of 0.75 mA/cm2 at 1.23 V (vs. a reversible hydrogen electrode, RHE) was achieved with an α-Fe2O3 thin film calcined at 800 °C. Incident photon-to-current conversion efficiency (IPCE) data showed that the quantum efficiency of the thin films was about 15% at 350 nm at an applied bias of 1.4 V vs. RHE. To improve the oxygen evolution reaction, we electrodeposited a Ni(OH)2/NiOOH catalyst (given as NiOOH) onto the α-Fe2O3 film and achieved the reduction of onset potential from 0.85 to 0.69 V vs. RHE. Electrochemical impedance spectroscopy and open-circuit photovoltage (OCP) measurements were used to estimate the flat-band potential of the thin films.

Original languageEnglish
Pages (from-to)130-138
Number of pages9
JournalApplied Catalysis A: General
Volume523
DOIs
Publication statusPublished - 5 Aug 2016

Keywords

  • Composite
  • Hematite
  • Nanoparticle
  • Photoelectrochemical water splitting

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