中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 25 No. 6 June 2015 |
（1. Department of Mining, Metallurgical and Materials Engineering,
Laval University, Ste-Foy G1V 0A6, Quebec, Canada;
2. Barrick Gold Corporation, Toronto M5J 2S1, Ontario, Canada）
Abstract:Anodic behavior of pure Au as compared to platinum (Pt) in H2SO4 solutions was considered by different electrochemical techniques for an appropriate insight. Cyclic voltammetry studies showed two oxidation and one film reduction peaks for Au, while one oxygen evolution reaction for Pt. Increasing H2SO4 concentration (from 0.5 to 1 mol/L) caused 2-fold increases in peak current density of Au. Increase in agitation promoted passive zone of Au, while it was negligible for Pt by potentiodynamic studies. Potentiostatic studies (2 h) at three anodic passive potentials in 1 mol/L H2SO4 showed that the admittance of Au was found to be the lowest at 1.4 V. Electrochemical noise measurements during the decay periods (16 h) after polarization showed that the thin passive film formed during potentiostatic polarization has been dissolved.
Key words: gold; passivation; sulfuric acid; electrochemical noise
