One-step electrodeposition from ionic liquid and water as a new method for 2D composite preparation

A new electrochemical method for preparing, in a one-step operation, thin layers of composites with matrix of metal (or alloy) and particles of metal (or alloy), has been developed. A thin CoPt-NPs/Ni-matrix composite has been obtained using two simultaneous electrodeposition processes in microemulsions of water droplets in ionic liquid. Water droplets contained the CoPt electrolytic bath, whereas the ionic liquid contained the nickel electrolytic bath. The application of a sufficient negative potential leads to the deposition of CoPt nanoparticles from the confined aqueous droplets. When the Ni(II) and PtCl62- in the drops in contact with the substrate are consumed, a layer of CoPt nanoparticles has been formed. Afterwards, the Ni(II) contained in the ionic liquid begins to deposit around and between CoPt nanoparticles, and a composite thin layer is obtained. The Co/Pt ratio in the nanoparticles corresponds to the Co(II)/Pt(IV) ratio in the aqueous droplets. The chronoamperometric curves allow detecting the different steps of the formation of the composite thin-layer. (C) 2014 Elsevier B.V. All rights reserved.