Direct Electrodeposition of UO_2 from Uranyl Bis(trifluoromethanesulfonyl)imide Dissolved in 1-Ethyl-3-methylimidazolium Bis(trifluoromethanesulfonyl)imide Room Temperature Ionic Liquid System

摘要

This study demonstrates a direct electrodeposition of UO_2 at a Pt cathode from a solution of uranyl bis(trifluoromethanesulfonyl)imide [UO_2(NTf_2)_2)] in a bulk room-temperature ionic liquid (RTIL), 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide (EMIM~+NTf_2~-). Cyclic voltammetry (CV) studies revealed two reduction waves corresponding to the conversion of uranium(VI) to uranium(IV), and a mechanism for the overall electroreduction is proposed. A controlled-potential experiment was performed, holding the reduction potential at-1.0V for 24h to obtain a brown-black deposit of UO_2 on the Pt cathode. The Faradaic efficiency of the reduction process was determined to be >80%. The UO_2 deposit was characterized by powder X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS).