Electrodeposition of Ta from 1-Butyl-1-methylpyrrolidinium bis trifluoromethylsulfonyl amide

Electrodeposition of Ta from 1-Butyl-l-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide 

Electrodeposition of tantalum thin layers in the water- and air-stable ionic liquid 1-butyl-l-methyl pyrrolidinium bis (trifluoromethylsulfonyl) amide at 200 °C using TaFs as a source of tantalum is presented in this protocol. The electrodeposition of Ta is not a straightforward process as, under the wrong experimental conditions. Ta subhalides can be formed, see Chapter 4.4. 

Platinum sheets of thickness 0.5 mm (Alfa, 99.99%) were used as a working electrode. Directly before use, the Pt substrate was cleaned for 10 min in an ultrasonic bath in acetone then heated in a hydrogen flame to red glow for a few minutes. Pt-wires (Alfa, 99.99%) were used as reference and counter electrodes, respectively. A quartz round flask was used as an electrochemical cell. The electrodeposition experiments were performed in an argon-filled glove box with water and oxygen below 1 ppm. 

The ionic liquid 1-butyl-l-methyl pyrrolidinium bis (trifluoromethylsulfonyl)amide was purchased from Merck KGaA(EMD) in ultrapure quality. TaFs (Alfa, 99.99%) and LiF (Alfa, 98.5%) were used without further purification. 

The electrodeposition ofTa was performed at 200 °C. It was found that the mechanical quality and the adherence of the electrodeposits improved as the temperature increased. Moreover, the quality and the adherence of the electrodeposit were found to be improved upon addition of LiF to the electrolyte [7, 8]. 

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