Fabrication of “clean” nano-structured metal materials on ionic liquid/water interface

• The metal nano-materials were fabricated on the immiscible IL/water interface.
• The method can achieve the control of different nano-structured metal materials.
• ILs present the selective adsorption on diffrent metal and the template effect
• The method is easy to obtain the “clean” metal nano-materials.

Transition metal Co, noble metal Pd and Pd2Co alloy nano-structured materials were fabricated on the immiscible ionic liquid (IL)/water interface with KBH4 as the reducing agent. The Co formed “clean” Co nano-films with a thickness of 1–2 nm on the IL/water interface displayed no adsorption of IL on Co films with the edge of Co nano-films curled to nano-tubes. However, the Pd and Pd2Co nanoparticles were picked up by IL from the aqueous phase forming a sphere-shaped structure, which exhibited the regular face-centered cubic (FCC) crystalline characteristic. Infrared (IR) spectra indicated a weak adsorption between the ionic liquid and the Pd and Pd2Co alloy nanoparticles. Applying ionic liquids as the immiscible solvent in the IL/aqueous system can yield “clean” nano-structured materials with controlled nano-structure on the IL/water interface as a result of the selective adsorption of the ionic liquid on the metal and the resulting template effects.