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In situ micro Raman investigation of electrochemically formed halide and pseudohalide films on mercury electrodes
Author(s) -
Brolo Alexandre G.,
Odziemkowski Marek,
Porter Julia,
Irish Donald E.
Publication year - 2002
Publication title -
journal of raman spectroscopy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.748
H-Index - 110
eISSN - 1097-4555
pISSN - 0377-0486
DOI - 10.1002/jrs.811
Subject(s) - raman spectroscopy , halide , mercury (programming language) , chemistry , electrochemistry , inorganic chemistry , electrode , analytical chemistry (journal) , organic chemistry , physics , computer science , optics , programming language
Oxidation of pure mercury electrodes was followed by in situ surface‐unenhanced Raman spectroscopy. A special spectroelectrochemical cell allowed the observation of spectral features of the oxidation products using a Raman microprobe. The electrochemical behaviour of mercury in basic solution, halide (F − , Cl − , Br − and I − ) and pseudohalide (SCN − ) media was investigated. Insoluble films were formed during the anodic processes in all these systems. The identities of the electrochemically generated films were clearly determined from the Raman spectra. The main product of the electrochemical oxidation of mercury in basic solutions was solid HgO. The anodic behaviour of mercury in the presence of halide yielded insoluble Hg 2 X 2 compounds (where X is the halide). The time dependence of the Raman signals indicated a diffusion‐controlled growth of the halide films. The oxidation of mercury in SCN − solutions also produced a solid precipitate [Hg 2 (SCN) 2 ]. Raman bands due to soluble mercury(II) thiocyanate complexes [Hg(SCN) x 2− x ], present in the electrochemical diffusion layer, were also observed. Copyright © 2002 John Wiley & Sons, Ltd.