Electrodeposition of Cu-Ni Alloy Electrodes with Bimodal Porosity and Their Use for Nitrate Reduction

Cu-Ni alloy layers with a bimodal porosity - a spongy material made of submicron dendrites, featuring macroscopic pores tens of microns large - can be deposited from baths containing the metal ions, sodium citrate and ammonium sulfate, using large current densities (-3 A cm-2) producing vigorous hydrogen evolution. Alloys with a broad range of compositions are obtained using baths with different Cu(II)/Ni(II) concentration ratios. Voltammetric experiments of nitrate reduction at compact and porous Cu-Ni RDEs show, in the latter case, lower overvoltage and higher peak currents, resulting from enhanced transport and improved catalytic activity.