Methylviologen mediated electrosynthesis of palladium nanoparticles stabilized with CTAC

Abstract

© 2016 The Electrochemical Society. All rights reserved.Efficient electrosynthesis of ultrasmall palladium nanoparticles stabilized with CTA+ cetyltrimethylammonium cations (Pd@CTA+) was carried out in an aqueous medium by methylviologen mediated electroreduction of poorly soluble aggregates ([PdCl4]2·2CTA+)n of [PdCl4]2- anionic complex with CTA+ cations on a glassy carbon electrode at potentials of theMV2+/MV·+ redox couple. ([PdCl4]2- ·2CTA+)n aggregates are reduced directly on the electrode at a low rate and the generated metal is deposited on the electrode. In the case of mediated reduction, the metal is not deposited on the cathode, and after passing of Q = 2 F quantitative conversion from [PdCl4]2- to Pd@CTA+ nanoparticles occurs in the solution bulk. These particles are positively charged (zeta-potential is 66.8 mV) and their hydrodynamic diameter is 18 nm. Separated Pd@CTAC nanoparticles are combined into larger aggregates due to coalescence of the organic shell. The predominant shape of metal nanoparticles is an imperfect sphere with a diameter of 5 ± 3 nm, and the average size of the metal crystallites is 4.66 nm.