铜铝双金属复合离子液体的电化学行为及电沉积铜机理

铜铝双金属复合离子液体是新型碳四烷基化技术所用的绿色催化剂，电化学处理是回收工业应用过程外排复合离子液体中金属铜的有效途径之一，为此需要深入研究其电化学行为和电沉积铜机理。循环伏安研究发现，铜铝双金属复合离子液体在Pt盘电极、W盘电极和玻碳电极上的还原过程均包括铜的欠电势沉积、Cu(Ⅰ)的还原和铜的超电势沉积，氧化过程均包括Cu→Cu(Ⅰ)、Cu(Ⅰ)→Cu(Ⅱ)。计时安培研究表明，铜的成核方式为三维瞬时成核。长周期实验结果显示Cu(Ⅰ)的浓度随着时间下降的趋势变缓，表明电沉积铜速率逐步下降。电沉积电势对沉积产物的形貌影响较大，-2.60 V下的产物形貌更平整致密。XRD结果表明在-1.20~-2.60 V电势下阴极电沉积只生成金属铜。

Electrochemical behavior and copper electrodeposition mechanism of Cu-Al bimetallic composite ionic liquid

Cu-Al bimetallic composite ionic liquid is a novel green catalyst for isobutane alkylation in oil refining industry, and small amount of catalyst is inevitably emitted during industrial application. Electrochemical treatment is one of the effective ways for the resource utilization of Cu-Al bimetallic composite ionic liquid, and the in-depth exploration of electrochemical behavior and electrodeposition mechanism provide theoretical guidance for the efficient utilization of metal resources. By cyclic voltammetry, it was found that there were three cathodic reduction regions for Cu-Al bimetallic composite ionic liquid in cyclic voltammograms on Pt electrode, W electrode and glassy carbon electrode, and the reactions were copper underpotential deposition, Cu(Ⅰ) reduction and copper overpotential deposition. The anodic oxidation peaks were Cu→Cu(Ⅰ), Cu(Ⅰ)→Cu(Ⅱ). For W electrode, the copper underpotential deposition process and the Cu(Ⅰ) reduction process were both irreversible electrochemical reaction processes controlled by diffusion. Chronoamperometry indicated that the nucleation and growth process of copper was three-dimensional instantaneous nucleation. Long-term electrodeposition of Cu-Al bimetallic composite ionic liquid showed that the decreasing trend of Cu(Ⅰ) concentration with time slowed down, indicating that the rate of copper electrodeposition decreased with time. The electrodeposition potential had a certain effect on the morphology of the deposited products. The morphology of the deposited product obtained at -2.60 V was smooth and dense, and presented regular granular shape. XRD patterns of the electrodeposits showed that there was only copper produced on cathode by the electrodeposition of the composite ionic liquid.