On the electrodeposition of titanium in ionic liquids

Faculty of Natural and Materials Sciences, Clausthal University of Technology, Robert-Koch-Str. 42, D-38678, Clausthal-Zellerfeld, Germany.
Physical Chemistry Chemical Physics (Impact Factor: 4.49). 05/2008; 10(16):2189-99. DOI: 10.1039/b800353j
Source: PubMed

ABSTRACT The ability to electrodeposit titanium at low temperatures would be an important breakthrough for making corrosion resistant layers on a variety of technically important materials. Ionic liquids have often been considered as suitable solvents for the electrodeposition of titanium. In the present paper we have extensively investigated whether titanium can be electrodeposited from its halides (TiCl(4), TiF(4), TiI(4)) in different ionic liquids, namely1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMIm]Tf(2)N), 1-butyl-1-methylpyrrolidinium bis(trifluoromethyl-sulfonyl)amide ([BMP]Tf(2)N), and trihexyltetradecyl-phosphonium bis(trifluoromethylsulfonyl)amide ([P(14,6,6,6)]Tf(2)N). Cyclic voltammetry and EQCM measurements show that, instead of elemental Ti, only non-stoichiometric halides are formed, for example with average stoichiometries of TiCl(0.2), TiCl(0.5) and TiCl(1.1). In situ STM measurements show that-in the best case-an ultrathin layer of Ti or TiCl(x) with thickness below 1 nm can be obtained. In addition, results from both electrochemical and chemical reduction experiments of TiCl(4) in a number of these ionic liquids support the formation of insoluble titanium cation-chloride complex species often involving the solvent. Solubility studies suggest that TiCl(3) and, particularly, TiCl(2) have very limited solubility in these Tf(2)N based ionic liquids. Therefore it does not appear possible to reduce Ti(4+) completely to the metal in the presence of chloride. Successful deposition processing for titanium in ionic liquids will require different maybe tailor-made titanium precursors that avoid these problems.

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    ABSTRACT: Direct electrodeposition of macroporous tin is achieved in a water- and air-stable room-temperature ionic liquid, namely, 1-ethyl-3-methylimidazolium-dicyanamide. This is the first example showing that tin nanowires interweaving into a porous structure can be obtained in ionic liquid without using any additive and template. The nanostructures, with great uniformity, high porosity, and good adhesion, were prepared by galvanostatic deposition at a current ranging from 0.3 to 1.2 mA cm(-2). Electrodeposition experiments performed in the 1-ethyl-3-methylimidazoliun-tetrafluoro borate ionic liquid under a similar condition generated granular tin rather than tin wires. (C) 2008 The Electrochemical Society.
    Electrochemical and Solid-State Letters 01/2008; 11(11). DOI:10.1149/1.2978089 · 2.32 Impact Factor
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    Physical Chemistry Chemical Physics 01/2008; 10(38). DOI:10.1039/b803650k · 4.49 Impact Factor
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