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首页> 外文期刊>Russian journal of electrochemistry >The Effect of Chemisorbed Sulfide Ions on the Gold Electrodeposition from Acidic Thiocarbamide Electrolytes
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The Effect of Chemisorbed Sulfide Ions on the Gold Electrodeposition from Acidic Thiocarbamide Electrolytes

机译：化学吸附的硫化物离子对酸性硫代氨基​​甲酸酯电解质电沉积金的影响

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Introducing sodium sulfide (about 10(-5) M) into acidic thiocarbamide solutions reduces the gold reduction overpotential. The reaction rate passes through a maximum at a potential of 0.1 V. The overpotential depends on the sulfide ion concentration and the time of electrode exposure to solution prior to the beginning of scanning. Transients of potential measured on a renewable gold electrode in thiocarbamide electrolytes containing catalytically active species served as the basis for calculations of the coefficient of trapping of sulfide ions by the growing gold deposit. The kinetics of gold electrodeposition at fixed surface coverages with adsorbed sulfide ions theta is studied. It is shown that at theta = const, the dependence of the reaction rate on the overpotential is described by the Tafel equation. It is shown that with an increase in theta, the effective values of exchange current and transfer coefficient increase from i(0) congruent to 10(-5) A/cm(2) and alpha congruent to 0.25 in pure solutions to alpha congruent to 0.5 and i(0) congruent to 10(-4) A/cm(2) theta >= 0.3 and then remains virtually unchanged. The reaction order decreases in the absolute magnitude, remaining negative. Thus for theta congruent to 0, p(k) = partial derivative log i/partial derivative log c = -1, whereas for theta >= 0.3, p(k) = -0.3. A possible explanation is proposed for the catalytic effect of the sulfide ion adsorption on the mechanism of the gold reduction from acidic thiocarbamide electrolytes.
机译：在酸性硫脲溶液中引入硫化钠（约10（-5）M）可减少金还原过电位。反应速率在0.1 V的电势下通过最大值。过电势取决于硫化物离子浓度和电极在扫描开始之前暴露于溶液中的时间。在含有催化活性物质的硫脲酰胺电解质中，在可再生金电极上测得的瞬态电位是计算生长中的金矿床捕集硫化物离子的系数的基础。研究了在固定的表面覆盖率下吸附有硫化物离子theta的金电沉积动力学。结果表明，在θ= const时，反应速率对超电势的依赖性由Tafel方程描述。结果表明，随着theta的增加，交换电流和传递系数的有效值从i（0）增至10（-5）A / cm（2），而在纯溶液中的α增至0.25，直至与0.5和i（0）等于10（-4）A / cm（2）theta> = 0.3，然后实际上保持不变。反应顺序以绝对幅度减小，保持负值。因此，对于等于0的theta，p（k）=偏导数log i /偏导数log c = -1，而对于theta> = 0.3，p（k）= -0.3。提出了一种可能的解释，说明硫化物离子吸附对酸性硫代氨基​​甲酸酯电解质还原金的机理的催化作用。

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