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

Autor: Saim Emin, Matjaz Valant, Bernard Dam, M. de Respinis, Wilson A. Smith, T. Mavrič
Rok vydání: 2016
Předmět:
Zdroj: Applied Catalysis A: General. 523:130-138
ISSN: 0926-860X
DOI: 10.1016/j.apcata.2016.06.007
Popis: We report on the photoelectrochemical (PEC) performance related to water oxidation of porous hematite (α-Fe 2 O 3 ) thin films, which were prepared by spin coating of colloidal core/shell Fe/Fe-oxide nanoparticles (NPs) on fluorine-doped SnO 2 (FTO) substrates. Oxidation of the obtained Fe/Fe-oxide films at 600 °C, 700 °C, and 800 °C in air yielded porous α-Fe 2 O 3 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/cm 2 at 1.23 V (vs. a reversible hydrogen electrode, RHE) was achieved with an α-Fe 2 O 3 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-Fe 2 O 3 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.
Databáze: OpenAIRE
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