Influence of supporting electrolyte on electrochemical formation of copper nanoparticles and their electrocatalytic properties

Comparative analysis of copper nanoparticles (CuNPs) obtained by electrodeposition on highly oriented pyrolytic graphite (HOPG) substrates from different supporting electrolytes containing sulphate anions, was performed. Voltammetric results indicated that Cu follows a diffusion-controlled nucleation and crystal growth model for three solutions studied (Na2SO4, H2SO4 Na2SO4+H2SO4). Na2SO4 solution found to be most effective because the reduction occurs at positive potential value, reaching highest current density. Analysis potentiostatic transients revealed process can described predominantly involving 3D-progressive mechanism, which corroborated scanning electron microscopy (SEM) analysis. SEM images showed high density hemispherical shaped particles sizes (mostly between 80-150 nm), randomly distributed HOPG surface electrolyte solution. In presence H2SO4, size dispersion decreased, resulting in with greater diameters (up 339 nm). The use Na2SO4+H2SO4 lower particle considerable dispersion, where very small crystallites are prevailing. Cyclic voltammetry used evaluate qualitatively catalytic activity CuNPs deposited towards nitrate reaction. An enhanced effect when were prepared either or electrolytes.