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Solid molybdenum nitride microdisc electrodes: fabrication, characterisation, and application to the reduction of peroxodisulfate

Solid molybdenum nitride microdisc electrodes: fabrication, characterisation, and application to the reduction of peroxodisulfate
Solid molybdenum nitride microdisc electrodes: fabrication, characterisation, and application to the reduction of peroxodisulfate
A new methodology was developed to fabricate solid molybdenum nitride microdisc electrodes for the first time. The MoN microrods were produced by heating Mo microwires in dry NH3 atmosphere for several hours. They were characterised by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The latter revealed the samples had crystallised in the δ3-MoN phase with a core of γ-Mo2N. Their electrochemical behaviour was probed for the reduction of Ru(NH3)63+. For this fast electron transfer the MoN microdisc electrodes returned similar voltammetric features to Pt microelectrodes. Their amperometric response was further tested with the reduction of peroxodisulfate. In contrast with other electrode materials, the reduction of S2O82− on MoN microdiscs delivered steady state voltammograms with well-defined diffusion controlled plateau. At low sweep rates, the limiting current was consistent with hemispherical diffusion and stable for at least 500 s. The diffusion coefficient of S2O82− derived from these results, 9.5 × 10−6 cm2 s−1, is in excellent agreement with previous work. At high sweep rates, the reduction of peroxodisulfate was found to be complicated by the simultaneous reduction of adsorbates. The results indicate that MoN is an ideal electrode material to monitor the concentration of peroxodisulfate under steady state conditions.
Molybdenum nitride, Microelectrodes, Peroxodisulfate
0013-4686
184-190
Bin Shafiee, Saiful Arifin
3a256723-4a8e-47a0-8900-1315b99c6c4e
Hector, Andrew L.
f19a8f31-b37f-4474-b32a-b7cf05b9f0e5
Denuault, Guy
5c76e69f-e04e-4be5-83c5-e729887ffd4e
Bin Shafiee, Saiful Arifin
3a256723-4a8e-47a0-8900-1315b99c6c4e
Hector, Andrew L.
f19a8f31-b37f-4474-b32a-b7cf05b9f0e5
Denuault, Guy
5c76e69f-e04e-4be5-83c5-e729887ffd4e

Bin Shafiee, Saiful Arifin, Hector, Andrew L. and Denuault, Guy (2019) Solid molybdenum nitride microdisc electrodes: fabrication, characterisation, and application to the reduction of peroxodisulfate. Electrochimica Acta, 293, 184-190. (doi:10.1016/j.electacta.2018.10.046).

Record type: Article

Abstract

A new methodology was developed to fabricate solid molybdenum nitride microdisc electrodes for the first time. The MoN microrods were produced by heating Mo microwires in dry NH3 atmosphere for several hours. They were characterised by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The latter revealed the samples had crystallised in the δ3-MoN phase with a core of γ-Mo2N. Their electrochemical behaviour was probed for the reduction of Ru(NH3)63+. For this fast electron transfer the MoN microdisc electrodes returned similar voltammetric features to Pt microelectrodes. Their amperometric response was further tested with the reduction of peroxodisulfate. In contrast with other electrode materials, the reduction of S2O82− on MoN microdiscs delivered steady state voltammograms with well-defined diffusion controlled plateau. At low sweep rates, the limiting current was consistent with hemispherical diffusion and stable for at least 500 s. The diffusion coefficient of S2O82− derived from these results, 9.5 × 10−6 cm2 s−1, is in excellent agreement with previous work. At high sweep rates, the reduction of peroxodisulfate was found to be complicated by the simultaneous reduction of adsorbates. The results indicate that MoN is an ideal electrode material to monitor the concentration of peroxodisulfate under steady state conditions.

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Accepted/In Press date: 7 October 2018
e-pub ahead of print date: 8 October 2018
Published date: 10 January 2019
Keywords: Molybdenum nitride, Microelectrodes, Peroxodisulfate

Identifiers

Local EPrints ID: 425271
URI: http://eprints.soton.ac.uk/id/eprint/425271
ISSN: 0013-4686
PURE UUID: 32c83baa-c53d-4061-9f0a-879980b83a2b
ORCID for Andrew L. Hector: ORCID iD orcid.org/0000-0002-9964-2163
ORCID for Guy Denuault: ORCID iD orcid.org/0000-0002-8630-9492

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Date deposited: 12 Oct 2018 16:30
Last modified: 15 Sep 2021 04:21

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