Electrode Reactions of Platinum Bromide Complexes in an Amide-Type Ionic Liquid

The electrode reactions of platinum bromide complexes were investigated in an amide-type room-temperature ionic liquid, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA). Platinum bromides were dissolved in BMPTFSA with addition of BMPBr. Ultraviolet and visible absorption spectra of the electrolytes revealed that Pt(II) and Pt(IV) species were dissolved as [(PtBr4)-Br-II](2-) and [(PtBr6)-Br-IV](2-), respectively. The Cyclic voltanunogram in BMPTFSA containing 10 mM [(PtBr6)-Br-IV](2-) showed two reduction peaks at -1.2 and -2.6 V, which can be assigned to reduction of [(PtBr6)-Br-IV](2-) and [(PtBr4)-Br-II](2-), respectively. The diffusion coefficients of the [(PtBr4)-Br-IV](2-) and [(PtBr6)-Br-IV](2-) at 25 degrees C were determined to be 1.5 x 10(-7) and 0.49 x 10(-7) cm(2) s(-1) in BMPTFSA, respectively, by chronoamperometry. Electrodeposition of metallic platinum was possible by galvanostatie cathodic reduction on a glassy carbon electrode in BMPTFSA containing 10 mM [(PtBr4)-Br-II](2-). In addition, platinum nano-particles (2-3 nm in diameter) formed and dispersed in the ionic liquid after potentiosiauc cathodic reduction at -2.6 V. Platinum nano-particles could be collected by heating the ionic liquid containing the nano-particles with carbon black at 200 degrees C. (C) 2013 The Electrochemical Society. All rights reserved.