Enhancement of hydrogen evolution in alkaline water electrolysis by using nickel-rare earth alloys

Abstract

Nickel-dysprosium (Ni-Dy) and nickel-samarium (Ni-Sm) alloys with 5 and 10 at% of rare earth metal were prepared by arc melting and by induction furnace melting, respectively. The alloys microstructure, morphology and chemical composition were inspected by scanning electron microscopy and energy dispersive X-ray analysis; phases crystal structure and lattice parameters were confirmed by X-ray diffraction analysis. The alloys were used for fabrication of electrodes for hydrogen evolution reaction (HER) in alkaline media and studied using polarisation measurements. Tafel analysis suggests that HER is limited by the Volmer step at all four electrodes. Determined kinetic parameters indicate better electrocatalytic performance for HER of Ni-RE alloys with 5 at% of RE compared to those with 10 at% of RE. Activation energies were evaluated to be in the 47-71 kJ mol-1 range.