Contribution to the knowledge of the electrochemical properties of actinides in non-aqueous media. III. The reduction of tetravalent thorium and tetravalent neptunium in various organic solvents

Electrochemical behavior of uranium(VI) in 1-butyl-3-methylimidazolium chloride and thermal characterization of uranium oxide deposit

“…The full width at half maximum (W 1/2 ) is 130 mV, which is higher than the theoretically expected value of 57 mV by Eq. (7) for two-electron reduction at 373 K. This large discrepancy is consistent [37] with irreversible nature of electroreduction of U(VI). It also leads to the value of α equal to ∼0.5:…”

Kinetics of Electrode Processes in Fused Salts and Organic Media Containing Thorium, Uranium or Neptunium Ions: Application to Concentrated Solutions

“…The experimental values of a (or a') when only one electron is involved are listed in column Τ (Table 1); they are compared with the values of the same parameters calculated from Sampled Polarography (SP) experiments when available. These data have been obtained in dilute solutions (5.10 -3 M to 2.5 10" 2 M) in previous work [1][2][3][4]. The SP has been described in this Journal [3].…”

“…Devanathan [8] considers that 1 + ψο η z~an an (7) where ζ is the valency of the ion. There is no simple relationship between η and ψ 0 : ψ 0 widely depends on concentration and on adsorption phenomena that are always prevailing in organic media [1,4], Thus we consider that the shift in the a values might be related to the different concentrations involved in each series of measurements. It is clear that for technological researches including high concentrations of actinides the Tafel-slope method should be preferred to the transient method.…”

“…Equipments, facilities and preparation of solutions (molten salts, organic media) have already been described [1,2,4]. UC1 3 , NpCl 3 , ThCl 4 , Cs 2 UCl 6 , Cs 2 NpCl 6 and Cs 2 U0 2 Cl4 are the feed materials.…”

“…In recent papers, we have reported fundamental electrochemical properties of the first actinides (Th, U, Np) in various organic media [1][2][3][4], These properties were deduced from transient electrochemical measurements such as cyclic voltammetry (CV), chronoamperometry (CA) or sampled polarography (SP) and the experiments were carried out in dilute solutions as to fit the conditions required to validate the basic equations involved in these methods.…”