Foreign Metal-Ions Tuned Electrochemical Processes in Ionic Liquids for Bulk-Metal Surface Treatment

Abstract

Electrochemical surface treatment of metals offers a cost-effective and convenient approach to create highly-functional surfaces and produce nanostructured materials, for a wide range of potential applications such as electrochemical sensing, energy storage, and manufacturing. Different from ordinary electrochemical surface-treatment technologies, our work has investigated a green ionic-liquid based electrochemical process which can be tuned by introducing foreign metal ions into the ionic liquid for the purpose mentioned above. In the electrochemical process, the foreign metal ions deposit onto a bulk metal in an electrodeposition mode, and are regenerated in a subsequent electro-dissolution mode. Their in-situ electrochemical deposition-dissolution on the bulk metal can be tuned by controlling electrochemical driving forces such as currents or overpotentials and the composition of the ionic-liquid bath. The structures of the treated bulk metal may be strongly dependent upon the interactions between the bulk metal and the foreign metal electrodeposited, and their electrochemical activities in the ionic liquid. Figure 1 shows three distinct nanostructures of gold surfaces treated using three different foreign metal ions added to an ionic liquid bath, suggesting that it is possible to not only prepare highly actively gold electrodes for sensor and catalyst applications, but also produce nanostructured materials such as nanoporous and nanospherical gold powder. In this presentation, we will introduce our green-chemistry method tuned by the electrochemical deposition and dissolution of foreign metal ions in ionic liquids, as well as the characterization of resulting surface nanostructures and their applications to electrochemical sensing and energy storage. Figure 1