Influence of organic ligands on electrodeposition and surface properties of nickel films

Presented results describe electrochemistry of Ni2+ complexes with glycinate (Gly−), etylenediamminetetraacetate (EDTA4−), acetate (Ac−), citrate (Cit3−), and formate (HCOO−) ligands in aqueous environment. Electrochemical tests indicated possibility of electrochemical synthesis of nickel films at potentiostatic conditions in Ac−, HCOO−, Gly− and Cit3− based systems. Deposition rate is strongly dependent on applied complexing agent. The highest deposition rate, ca. 1900 ng s− 1 cm− 2 (E = − 1.1 V vs. Ag/AgCl) was observed in system containing formate nickel complexes. Registered potentiostatic current - time curves combined with electrochemical quartz crystal microbalance (EQCM) indicated the highest current efficiency for Gly− based system i.e. 0.75 (954 ng s− 1 cm− 2, E = − 1.1 V vs. Ag/AgCl). Voltammograms and XRD patterns indicated that nickel electrodeposition is accompanied by hydrogen absorption. XPS technique indicated the presence of nickel hydroxides on electrodeposited films surface.