Comparison of electrodeposition of silver in ionic liquid microemulsions

Both ionic liquid (IL) and water are typical green solvents and have high electric conductivity. The use of IL microemulsions as templates and media for electrochemical synthesis of nano-materials is attractive. In this work, water-in-ionic liquid (W/IL) microemulsion and ionic liquid-in-water (IL/W) microemulsion were prepared, in which hydrophobic ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate was used. The cyclic voltammetry (CV) behavior and electroplating in the W/IL and IL/W microemulsion systems containing silver nitrate were investigated for the first time. Both the CV curves exhibit the presence of reduction and oxidation peaks corresponding to the deposition and dissolution of silver from the two microemulsion systems. However, the CV obtained from IL/W microemulsion system exhibits a crossover, which is different from that obtained from W/IL microemulsion system. The electrodeposits obtained from W/IL microemulsion system are nano-granular, while those obtained from IL/W microemulsion system are planar. These results are attributed to the different microenvironments of the microemulsions.