A Role of the Plating Regime in the Deposition of Bismuth Films onto a Carbon Paste Electrode. Microscopic Study

A microscopic study is presented based on observations of bismuth films deposited from various plating solutions and under different experimental conditions onto the carbon paste surface. Electrolytic plating of bismuth films was performed either as simulation of preconcentration in‐situ from a 0.2 M acetate buffer containing 5×10^?5 M Bi³⁺ (pH 4.25), or as external deposition from various plating solutions: 0.1 M acetate buffer with 5×10^?4 M Bi³⁺ (pH 4.50), 0.5 M HCl with either 0.001 M BiCl₃ or 0.005 M BiCl₃ , 0.5 M HCl+0.5 M KBr+0.005 M BiCl₃ , and 0.5 M HCl+0.5 M KI+0.005 M BiCl₃ (all pH≈0.5). Scanning electron microscopic images of the bismuth films showed a considerable variability in structure and compactness of the deposited layer in dependence on experimental conditions chosen such as the concentration of Bi(III) species, the total acidity of plating media, the stability of complexes of Bi(III) with halogenide anions or the deposition potential applied.