Ionic liquids as green electrolytes for the electrodeposition of nanomaterials

Abstract

Ionic liquids, especially air and water stable ones, experience much attention, since they have attractive physical properties. We exemplify in this paper the potential of ionic liquids in the electrodeposition of nanocrystalline metals without additives. The results show that nanocrystalline copper and aluminium can be electrodeposited in the air and water stable ionic liquids 1-butyl-1-methylpyrrolidinium trifluoromethanesulfonate ([BMP]TFO) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide ([BMP]Tf₂N), respectively, on conventional solid electrodes with sufficient electronic conductivity. Generally, the obtained Al or Cu deposits are shiny, dense and adherent with very fine crystallites with average sizes of about 30 and 40 nm, respectively. The [BMP]⁺ cation might act as a grain refiner, leading to nanosized deposits. The results of first attempts to use plasmas as mechanically contact-free electrodes for the cathodic deposition of nanoscaled metals (glow discharge electrodeposition) are also presented. The relevance of our results for the development of a green process to make nanomaterials as catalysts for fuel processing is briefly discussed.