Electrodeposition of Ni−Rh Alloys and their Use as Cathodes for Nitrate Reduction in Alkaline Solutions
Compact Ni−Rh alloys are electrodeposited potentiostatically on rotating disk and sheet electrodes; film compositions are adjusted by varying bath composition and deposition potential Edep. SEM images of these alloys show a compact, globular morphology for Rh contents up to 30 at%, and a smoother as...
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Veröffentlicht in: | ChemElectroChem 2023-03, Vol.10 (6), p.n/a |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | Compact Ni−Rh alloys are electrodeposited potentiostatically on rotating disk and sheet electrodes; film compositions are adjusted by varying bath composition and deposition potential Edep. SEM images of these alloys show a compact, globular morphology for Rh contents up to 30 at%, and a smoother aspect for films with a medium‐to‐high content of Rh. XRD spectra show the formation of a single crystalline phase, with diffraction peaks in intermediate positions between those of the constituent elements. Data analysis indicates that crystal lattice parameters vary with composition according to Vegard's law. Linear voltammetries of nitrate reduction in alkali highlight a maximum of activity, in terms of reduction current, for alloys in the range of 10–30 at.% Rh. Prolonged electrolysis at appropriate potential performed with Ni85Rh15 alloy shows, in comparison with pure Ni and pure Rh: much increased activity and faster abatement of nitrate; lower production of the undesired nitrite species; higher selectivity towards production of ammonia.
Efficient nitrate abatement: Compact thin layers of Ni−Rh alloys are electrodeposited from acidic sulfate baths. XRD shows formation of a single crystalline phase of substitutional solid solution. Ni‐rich alloys with 10–30 at% Rh display higher activity for electrochemical nitrate reduction in alkali than the parent metals, with faster abatement of nitrate, increased selectivity to ammonia production and lower charge loss in parasitic processes. |
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ISSN: | 2196-0216 2196-0216 |
DOI: | 10.1002/celc.202201122 |