电化学沉积金属铜的分形枝晶生长控制与性能

Growth control and properties of dendrite-like copper crystal synthesized by electrochemical deposition

以CuSO4为前驱体,HCl为添加剂,采用电化学沉积方法,在室温条件下制得了μm级、面心立方结构分形铜的枝状晶体,研究了铜离子浓度、硫酸浓度、电流密度、沉积时间、氯离子浓度等实验参数对分形枝状铜晶体尺寸、结构的影响。结果表明：硫酸的浓度对铜沉积物结构无明显影响;随着Cu^2＋浓度的不断增大,铜沉积物的分形效果越来越明显;增大电流密度（0.4-1.6 A.cm^-2）,铜沉积物由致密向多分枝的开放型转变;延长沉积时间（大于等于5 min）,可获得含大量次级分枝铜的晶体;适当增加盐酸用量（0.05-0.20 mol/L）,铜沉积物枝晶尺寸显著减小。最后讨论了分形枝晶铜在碱性条件下氧化甲醇的电化学性能。

Using copper sulfate as the precursor and hydrochloric acid as the additive,dendrite-like copper crystals（DLCCs）with micrometer size and face-cubic structure were successfully fabricated by electrochemical deposition at room temperature.Effects of experimental parameters,such as concentrations of sulfate acid,copper sulfate,and hydrochloric acid,current density and deposition time,on size and structure of the DLCCs were investigated.It is indicated that the concentration of sulfate acid does not affect the crystal structure markedly.Whereas fractal structure of copper becomes much clearer with the increasing of the copper ion concentration.When the current density is improved from 0.4 to 1.6 A·cm-2,the deposit translates into open structure with much more dendrite-like crystals from the previous compact solids.More DLCCs with subfractal structure will be obtained if deposition time is prolonged（no less than 5 min）.With the addition of 0.05 to 0.20 mol/L HCl,the size of copper branches dramatically reduces.Electrochemical properties of DLCCs catalyzing methanol in alkali solution was also investigated.