Electrochemical behavior of zirconium(IV) in 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide ionic liquid

• Zirconium is the component of metallic fuel.
• Electrochemical behavior of Zr(IV) in ionic liquid medium.
• Diffusion coefficient of zirconium (IV).
• Nucleation of zirconium metal for the first time in ionic liquid
• Characterisation of the metallic zirconium

Zirconium is a constituent of metallic fuel in a nuclear reactor. The electrochemical behavior of Zr(IV) in the room temperature ionic liquid, 1-butyl-3-methyl imidazolium bis(trifluoromethylsulfonyl) imide (C4mimNTf2), was studied by various transient electrochemical techniques. The cyclic voltamogram of Zr(IV) in C4mimNTf2 consisted of a scant cathodic wave occurring at the potential of + 0.2 V(Vs Pd), due to the reduction of Zr(IV) to Zr(II), and a prominent reduction occurring at the onset of − 1.3 V (Vs Pd), due to Zr(II) to Zr(0). The metallic deposit was characterized by SEM-EDX and XRD analysis. A nucleation loop was observed at − 1.6 V (Vs Pd). The cathodic peak current increased and marginally shifted cathodically with the increase of scan rate. The apparent diffusion coefficient of Zr(IV) in C4mimNTf2 was determined to be 10− 10 cm2/s and a five-order increase in apparent diffusion coefficient (10− 5 cm2/s) was observed with the onset of nucleation at − 1.6 V (Vs Pd). The nucleation growth and decay of chronocurrent transient was fitted into instantaneous and progressive nucleation models. The nucleation phenomenon also altered the nature of chronopotentiogram of Zr(IV) with a drop from rest potential followed by increase in the potential of working electrode in the early part of the transient. The study indicated the possibility of electrodeposition of zirconium from C4mimNTf2 ionic liquid.