Anodisation of copper in thiourea- and formamidine disulphide-containing acid solution.: Part I. Identification of products and reaction pathway

摘要: Abstract The anodic behaviour of copper in aqueous 0.5 M sulphuric acid containing different amounts dissolved thiourea or formamidine disulphide was investigated at 298 K, combining data from electrochemical polarisation, chemical analysis, UV–vis spectroscopy, XPS and EDAX structural information on copper–thiourea complexes. main reactions depend the applied potential initial concentration. In range −0.30≤E≤0.075 V (versus SCE), electro-oxidation to disulphide, formation Cu(I)–thiourea soluble complexes, complex polymer-like films, are most relevant processes. this film depends certain critical thiourea/copper ion molar concentration ratios reaction interface. At low positive potentials, former is under intermediate kinetic control, with diffusion solution playing a key role. For E≥0.075 V, Cu(II) ions formed gradually changed another one consisting sulphide residual copper. new assists localised electrodissolution A pathway for anodisation these media high advanced.