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Anodically polarized nickel electrodes in DMSO or DMF solutions of pseudohalide ions: IR spectroelectrochemical studies

Abstract
A novel subtractively normalized interfacial Fourier transform infrared spectroscopic (SNIFTIRS) investigation of anodically polarized nickel electrodes in pseudohalide-containing DMF or DMSO solutions (i.e. OCN⁻, SCN⁻, SeCN⁻), in supporting electrolyte, tetrabutylammonium perchlorate (TBAP), is presented. In general, the data showed that nickel demonstrated irreversible anodic dissolution in all solutions studied at very high values of the applied potential, > +500 mV (AgCl/Ag). The predominant speciation of nickel in these systems was as complex ions consisting of Ni²⁺ ion complexed to pseudohalide ions and solvent molecules. Insoluble films and dissolved CO₂ were also detected, though mostly in the Ni/OCN⁻ systems studied. Ni(II)/pseudohalide complex ion species detected were modeled using solutions containing Ni²⁺ ion mixed with pseudohalide ion in different mole ratios. In general, the Ni/OCN⁻ electrochemical system behaved differently relative to those of Ni/SCN⁻ and Ni/SeCN⁻ due to the difference in colors observed in cell solutions after SNIFTIRS experiments which was mirrored in the model solutions. Ni(II)-cyanate species had a different, coordination geometry and gave a characteristic bright blue color due possibly to Ni(NCO)₄²⁻ ion while Ni(II) thiocyanate and selenocyanate complex ion species had octahedral coordination geometries containing solvent and one coordinated pseudohalide ion and formed greeny yellow solutions.
Type
Journal Article
Type of thesis
Series
Citation
Alwis, L. K. H. K., Mucalo, M. R., & Ingham, B. (2013). Anodically polarized nickel electrodes in DMSO or DMF solutions of pseudohalide ions: IR spectroelectrochemical studies. Journal of the Electrochemical Society, 160(11), H803-H812.
Date
2013
Publisher
ELECTROCHEMICAL SOC INC
Degree
Supervisors
Rights
© 2013 The Electrochemical Society