Electrochemical dissolution of gold in presence of chloride and bromide traces studied by on-line electrochemical inductively coupled plasma mass spectrometry

Electrochemical dissolution of gold in the presence of halide ions is traditionally considered as a model case in metal corrosion and passivation studies. Due to a relatively low sensitivity of the conventional techniques, such studies were predominantly limited to electrolytes with high concentrations of halides. The current work employs a special electrochemical scanning flow cell with online inductively coupled plasma mass spectrometry (SFC-ICP-MS) that allows overcoming those limitations, enabling the quantification of gold dissolution in the presence of chloride and bromide traces (1 μM ≤ [Cl−/Br−] ≤ 100 μM). Moreover, time- and potential-resolved gold dissolution profiles under different potential programs are provided. Based on the experimental results, a tentative mechanism of gold dissolution based on the catalyzing role of hydroxyl and halide anions is discussed