Direct reversible voltammetry and electrocatalysis with surface-stabilised Fe2O3 redox states

Cummings, Charles Y.; Bonné, Michael J.; Edler, Karen J.; Helton, Matthew E.; McKee, Anthony; Marken, Frank

doi:10.1016/j.elecom.2008.09.018

Cited by 40 publications

(38 citation statements)

References 16 publications

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“…In this reaction, the charge transfer (reduction of Fe(III) to Fe(II) proceeds in solid state as it has already been reported [18,19,62]. The overview of peak potentials of Fe(III) oxides in acetate buffer is in Table 2.…”

Section: Non-oxidic Species With Uv Band B4 and Invisible By Voltammetrymentioning

confidence: 73%

Speciation of Fe in Fe-modified zeolite catalysts

Smoláková

Grygar

Čapek

et al. 2010

Journal of Electroanalytical Chemistry

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Section: Non-oxidic Species With Uv Band B4 and Invisible By Voltammetrymentioning

confidence: 73%

Speciation of Fe in Fe-modified zeolite catalysts

Smoláková

Grygar

Čapek

et al. 2010

Journal of Electroanalytical Chemistry

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“…They have also found that np-Fe 3 O 4 provide a more compatible matrix for proteins such as hemoglobin while preventing their denaturation. Cummings et al 7 have found that an ITO-coated electrode modified with maghemite nanoparticles ( -Fe 2 O 3 , ∼ 10 nm) may exhibit Fe(IV) surface species that are reactive towards oxidation of glucose to gluconolactone in carbonate buffer medium. McKenzie et al 8 have shown that hydrous ferric oxide nanoparticles adsorbed onto borondoped diamond electrodes act as an efficient electrocatalyst in a heterogenous Fenton-type process that drives the oxidation of hydroxide to dioxygen.…”

Section: Introductionmentioning

confidence: 99%

Iron Oxide Nanostructured Electrodes for Detection of Copper(II) Ions

Santos¹,

Souza²,

Letti³

et al. 2014

j nanosci nanotechnol

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Iron oxide nanostructured (ION) electrodes were assembled layer-by-layer onto ITO-coated glass substrates and their structure, morphology, and electrochemical properties were investigated, the latter aiming at the development of a chemical sensor for Cu 2+ . The electrodes were built by immersing the substrate alternately into an aqueous colloidal suspension of positively charged magnetite nanoparticles (np-Fe 3 O 4 , 8 nm) and an aqueous solution of anionic sodium sulfonated polystyrene (PSS). The adsorbed amount of both materials was monitored ex-situ by UV-vis spectroscopy and it was found to increase linearly with the number of deposition cycles. The resulting films feature a densely-packed structure of magnetite nanoparticles, as suggested by AFM and Raman spectroscopy, respectively. Cyclic voltammograms of electrodes immersed in acetate buffer (pH 4.6) displayed three electrochemical events that were tentatively ascribed to the reduction of Fe(III) oxy-hydroxide to magnetite, reduction of maghemite to magnetite, and finally oxidation of magnetite to maghemite. The effect of np-Fe 3 O 4 /PSS bilayers on the ION electrode performance was to increase the anodic and cathodic currents produced during electrochemical oxidationreduction of the Fe(CN) 3−/4− redox couple. With more bilayers, the ION electrode provided higher anodic/cathodic currents. Moreover, the redox couple exhibited a quasi-reversible behavior at the ION electrode as already observed with other working electrode systems. Fitting of voltammetry data provided the apparent electron transfer constants, which were found to be higher in ION electrodes for both redox couples (Fe(CN) 3−/4− and Cu 2+/0 ). By means of differential pulsed anodic stripping voltammetry, the ION electrodes were found to respond linearly to the presence of Cu 2+ in aqueous samples in the range between 1.0 and 8 0 × 10 −6 mol · L −1 and displayed a limit of detection of 0 3 × 10 −8 mol · L −1 . The sensitivity was ∼ 0.6 A/ mol · L −1 . In standard addition and recovery experiments performed with tap water the recovery was about 102%-119%. In similar experiments conducted with ground and instant coffee samples the recovery was 92.5% and 103%, respectively. Furthermore, the ION electrodes were almost insensitive to the presence of common interfering ions, such as Zn 2+ , Mn 2+ , Ni 2+ , and Fe 3+ , even at concentrations ten times higher than that of Cu 2+ .

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“…It has been reported that surface Fe sites may be oxidized to the higher valence state of Fe IV under certain conditions;f or instance, the formation of Fe IV has been observed in positive potential scanning, depending on the experimental conditions. [35,36] Ah igher valence Fe IV speciesh as also been found to be active for glucose oxidation. [36] Similarly to Fe IV ,Ni IV has also been implicated as an active catalytic species, and may be generatedd uring the process of electrochemical water oxidation.…”

Section: Resultsmentioning

confidence: 97%

“…[35,36] Ah igher valence Fe IV speciesh as also been found to be active for glucose oxidation. [36] Similarly to Fe IV ,Ni IV has also been implicated as an active catalytic species, and may be generatedd uring the process of electrochemical water oxidation. [37,38] Based on these reports, we surmise that Fe www.chemeurj.org may also be formed on the surfaceo fF eOOH.…”

Section: Resultsmentioning

confidence: 97%

Abnormal Cathodic Photocurrent Generated on an n‐Type FeOOH Nanorod‐Array Photoelectrode

Chen

Lyu

Liu

et al. 2016

Chemistry A European J

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A simple, wet-chemical method for the synthesis of an FeOOH nanorod-array photoelectrode on fluorine-doped tin oxide (FTO) glass is reported. Nanorods of diameter about 35 nm and length about 300 nm have been vertically grown on an FTO substrate. Upon calcination, the FeOOH phase could be easily converted to a hematite structure while maintaining the shape of the nanorod array. An interesting abnormal cathodic photocurrent is generated on the FeOOH nanorod-array photoelectrode under illumination, which is totally different from that obtained on a calcined hematite photoelectrode under the same experimental conditions. The cathodic photocurrent density generated on the FeOOH photoelectrode can also be tuned by applying an electrochemical anodic or cathodic treatment. Detailed analysis has revealed that higher valence state Fe(IV) species in the FeOOH photoelectrode play an important role in sacrificing the photoexcited electrons for generation of the cathodic photocurrent. Comparison between the FeOOH and hematite photoelectrodes allows for a better understanding of the interplay between crystal structure, surface reactions, and photocurrent. The findings on this new abnormal phenomenon could also provide guidance for the design of new types of semiconducting photoelectrochemical devices.

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Direct reversible voltammetry and electrocatalysis with surface-stabilised Fe2O3 redox states

Cited by 40 publications

References 16 publications

Speciation of Fe in Fe-modified zeolite catalysts

Speciation of Fe in Fe-modified zeolite catalysts

Iron Oxide Nanostructured Electrodes for Detection of Copper(II) Ions

Abnormal Cathodic Photocurrent Generated on an n‐Type FeOOH Nanorod‐Array Photoelectrode

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