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In this paper we report on the reactivity of adsorbed cyanide deriving from ligand release during metal electrodeposition from cyanocomplex solutions of Au(I), Au(III), Ag(I) and Cu(I) in H 2 O and D 2 O. When CN¯ is adsorbed at cathodic potentials in excess of the HER threshold, metal-dependent reactivity can be detected by SERS. Finite surface coverages with adsorbed CN¯ at such cathodic potentials can be obtained only if CN¯ is delivered directly to the cathode surface as by decomplexing of the cyanocomplexes of the metals undergoing cathodic reduction. In Au(I) and Au(III) baths, Au-CN¯ reacts with Au-H• and is hydrogenated to adsorbed CH 2 =NH and CH 3 -NH 2 .In Ag(I) baths, Ag-CN¯ reacts with Ag-H • giving rise to polycyanogens. No reactivity of Cu-CN¯ was found, under otherwise identical conditions. Our conclusions are supported also by dedicated DFT molecular computations.

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This paper reports an in situ Raman study of Cu electrodeposition from an acidic sulfate solution in the presence of bis-͑3-sulfopropyl͒-disulfide Na salt ͑SPS͒. In the absence of chloride, in situ surface-enhanced Raman spectra scarcely show few labile features in a narrow range of cathodic potential. When Cl − ions are added to the deposition bath, several features are clearly visible in the spectra, showing that SPS is adsorbed on the copper surface in a wide potential window during Cu electroplating.

In this paper we investigated the electrodeposition of Ag-Au alloys from cyanide baths by in situ surface-enhanced Raman spectroscopy. The spectroelectrochemical investigation is complemented by electrochemical experiments (cyclic voltammetry and potentiostatic electrodeposition) and structural (X-ray diffraction), morphological (scanning electron microscopy) and compositional (energy dispersive spectroscopy) characterisation of the alloys. Electrochemical and spectroelectrochemical results on singlemetal electrodeposition baths of otherwise identical composition are reported for comparison. Single-phase deposits of composition ranging from 13% to 75% Au were obtained potentiostatically. The voltammetric behaviour was correlated to the vibrational characteristics of adsorbed ligands. Quantitative and qualitative differences in interfacial chemistry as a function of applied potential were assessed and explained on the basis of variations in the nature of cyanide-related surface species. The cyanide and metaladsorbate stretching bands have been analysed.

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This paper deals with the effects of PEG during Cu electrodeposition from an acidic sulphate solution. This investigation was carried out with electrochemical and spectroelectrochemical techniques. Potentiostatically grown layers were examined by scanning electron microscopy. Adsorption of PEG on the growing Cu surface can be inferred from electrokinetic, SERS and morphological evidence: variations of the estimated exchange current density, qualitative and quantitative differences in the potentiostatic transients, changes on the cathodic current efficiency, effects on the three-dimensional crystallisation mode under both compact and dendritic growth conditions, appearance of surface-enhanced PEG-related Raman bands. SERS spectra revealed cathodic reactivity of adsorbed PEG.