Ni-La composite coating obtained using deep eutectic solvent and its electrocatalytic activity

The overpotential of hydrogen evolution reaction is one of the aspects which results in low efficacy of water electrolysers. There is a constant search for new ways to improve the catalytic activity, especially of nickel-based materials. Addition of lanthanum results in synergism and high activity towards the hydrogen evolution reaction. Due to the application of deep eutectic solvents which are characterized by a wide electrochemical window and good solvent properties for metal ions, it was possible to deposit the lanthanum-nickel alloy coating which was composed of around 40% of La. Hydrogen evolution reaction conducted on this layer resulted in a reduction of overpotential by 129 mV in comparison to pure Ni layer at current density of 1 mA cm(-2). Other kinetic parameters, such as Tafel slope and exchange current density, were also significantly improved. [GRAPHICS] .