dc.contributor.author
Smith, Rodney D. L.
dc.contributor.author
Pasquini, Chiara
dc.contributor.author
Loos, Stefan
dc.contributor.author
Chernev, Petko
dc.contributor.author
Klingan, Katharina
dc.contributor.author
Kubella, Paul
dc.contributor.author
Mohammadi, Mohammad Reza
dc.contributor.author
González-Flores, Diego
dc.contributor.author
Dau, Holger
dc.date.accessioned
2019-07-09T11:20:31Z
dc.date.available
2019-07-09T11:20:31Z
dc.identifier.uri
https://refubium.fu-berlin.de/handle/fub188/24989
dc.identifier.uri
http://dx.doi.org/10.17169/refubium-2746
dc.description.abstract
The dramatic change in electrochemical behavior of nickel (oxy)hydroxide films upon incorporation of Fe ions provides an opportunity to establish effective electrocatalyst design principles. We characterize a photochemically deposited series of Fe–Ni (oxy)hydroxides by X-ray absorption spectroscopy and track the voltage- and composition-dependence of structural motifs. We observe a trigonal distortion in di-μ-hydroxo bridged NiII–NiII motifs that is preserved following a symmetric contraction of Ni–O bond lengths when oxidized to di-μ-oxo NiIV–NiIV. Incorporation of Fe ions into the structure generates di-μ-hydroxo NiII–FeIII motifs in which Ni–Fe distances are dependent on nickel oxidation state, but Fe–O bond lengths are not. This asymmetry minimizes the trigonal distortion in di-μ-hydroxo NiII–FeIII motifs and neighboring di-μ-hydroxo NiII–NiII sites in the reduced state, but exacerbates it in the oxidized state. We attribute both the Fe-induced anodic shift in nickel-based redox peaks and the improved ability to catalyze the oxygen evolution reaction to this inversion in geometric distortions. Spectroelectrochemical experiments reveal a previously unreported change in optical absorbance at ca. 1.5 V vs. RHE in Fe-containing samples. We attribute this feature to oxidation of nickel ions in di-μ-hydroxo NiII–FeIII motifs, which we propose is the process relevant to catalytic oxygen evolution.
en
dc.rights.uri
http://www.fu-berlin.de/sites/refubium/rechtliches/Nutzungsbedingungen
dc.subject
Electrocatalysts
en
dc.subject
X-ray absorption spectroscopy
en
dc.subject
catalytic oxygen evolution
en
dc.subject.ddc
500 Natural sciences and mathematics::530 Physics::530 Physics
dc.title
Geometric distortions in nickel (oxy)hydroxide electrocatalysts by redox inactive iron ions
dc.type
Wissenschaftlicher Artikel
dcterms.bibliographicCitation.doi
10.1039/C8EE01063C
dcterms.bibliographicCitation.journaltitle
Energy & Environmental Science
dcterms.bibliographicCitation.number
9
dcterms.bibliographicCitation.pagestart
2476
dcterms.bibliographicCitation.pageend
2485
dcterms.bibliographicCitation.volume
11
dcterms.bibliographicCitation.url
https://pubs.rsc.org/en/Content/ArticleLanding/2018/EE/C8EE01063C
refubium.affiliation
Physik
refubium.affiliation.other
Institut für Experimentalphysik
refubium.funding
Open Access Publikation in Allianzlizenz
refubium.resourceType.isindependentpub
no
dcterms.accessRights.openaire
open access
dcterms.isPartOf.issn
1754-5692 (Print)
dcterms.isPartOf.issn
1754-5706 (Online)