Palladium electrodeposition in 1-butyl-1-methylpyrrolidinium dicyanamide ionic liquid

In aqueous solutions, Pd electrodeposition is complicated by hydrogen embrittlement. As an alternative, ionic liquids have been suggested. However, the physical and chemical properties of each ionic liquid are unique. In this work, Pd electrodeposition was investigated on Ni at room temperature in one of the promising air- and water-stable ionic liquids, 1-butyl-1-methylpyrrolidinium dicyanamide (O3mpyrr] [DCA1). The goal of this study was to elucidate kinetics of the Pd electro-reduction in [Brnpyrr][DCA] on Ni using current-time transient method (CTI) and its effect on the structure of the Pd deposits using chronoamperometry. The kinetics of the electrodeposition process was found to be limited by mass transfer. The nucleation and growth mechanism on Ni, extracted from the CTI's and analyzed using Scharifker and Hills model, showed potential dependence; at lower overpotential, the nucleation and growth was progressive that transitioned to instantaneous as the overpotential increased. Pd films obtained after potential holds for 30 min were crack-free and had a surface morphology that was less granular when overpotential increased showing clear potential-dependent nucleation and growth. Evidence of [Bmpyrrl[DCA] on the surface of the Pd films was observed using X-ray photoelectron spectroscopy. The Pd films had well-defined crystallinity only after heat treatment at 600 degrees C. (C) 2015 Elsevier Ltd. All rights reserved.