Growth of Ordered Iron Oxide Nanowires for Photo-electrochemical Water Oxidation
AuthorsMoreno Garcia, Julian
Khan, M. A.
Ivanov, Yurii P.
Holguin Lerma, Jorge Alberto
Ooi, Boon S.
KAUST DepartmentPhysical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
SABIC Corporate Research and Development Center, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
KAUST Grant NumberOSR-2016-CRG5-2956
Online Publication Date2019-10-10
Print Publication Date2019-12-23
Embargo End Date2020-10-10
Permanent link to this recordhttp://hdl.handle.net/10754/660509
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AbstractThis work reports the synthesis of ordered and vertically aligned iron oxide nanowires for photo-electrochemical (PEC) water oxidation. The nanowires exhibited promising PEC activity for water oxidation with saturated photocurrents of ∼0.8 mA cm-2 at 1.23 V vs RHE. Various factors inevitably affect their photochemical activity such as crystallinity, morphology, compositional gradient, and surface states. They were studied with HRTEM, EELS, and Raman shift techniques. The nanowires had complex compositional and morphological structures at nano and atomic scales. The nanowires annealed at 350 °C had an outer shell dominated by Fe3+ cations, while the core had mixed oxidation states of iron cations (+2 and +3). In contrast, nanowires annealed at 450 °C are fully oxidized with Fe3+ cations only and were found to be more active. At the same time, we observed anisotropic compositional gradients of nickel cations inside the iron oxide, originating from the nickel support film. Our work shows that the methodology used can affect the composition of the surface and near surface of the grown nanowires. It therefore points out the importance of a detailed analysis, in order to obtain a realistic structure-activity relationship in photo-electrocatalysis.
CitationMoreno, J. A., Khan, M. A., Ivanov, Y. P., Lopatin, S., Holguín-Lerma, J. A., Marinaro, G., … Kosel, J. (2019). Growth of Ordered Iron Oxide Nanowires for Photo-electrochemical Water Oxidation. ACS Applied Energy Materials. doi:10.1021/acsaem.9b01343
SponsorsThis publication is based upon work supported by the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No. OSR-2016-CRG5-2956.
PublisherAmerican Chemical Society (ACS)
JournalACS Applied Energy Materials