Electrodeposition of antimony in a water-stable 1-ethyl-3-methylimidazolium chloride tetrafluoroborate room temperature ionic liquid

The electrochemistry and electrodeposition of antimony were investigated on glassy carbon and nickel electrodes in a basic 1-ethyl-3-methylimidazolium chloride-tetrafluoroborate room temperature ionic liquid. Cyclic voltammetry results show that Sb(III) may be either oxidized to Sb(V) via a quasi-reversible charge-transfer process or reduced to Sb metal. Diffusion coefficients for both Sb(III) and Sb(V) species were calculated from rotating disc voltammetric data. Analysis of chronoamperometric current-time transients indicates that the electrodeposition of Sb on glassy carbon proceeded via progressive three-dimensional nucleation with diffusion-controlled growth of the nuclei. Raising the deposition temperature results in decreased average radius of the individual nuclei. Dense deposits can be obtained within a deposition temperature range between 30 to 120°C. Scanning electron microscopy revealed dramatic changes in the surface morphology of antimony electrodeposits as a function of deposition temperature; deposits obtained at 30°C had a nodular appearance whereas those obtained at 80 and 120°C consisted of evenly distributed fine polygonal crystals.