INFLUENCE OF PHYSICOCHEMICAL PROPERTIES OF ALKALINE-SOLUTIONS AND TEMPERATURE ON THE HYDROGEN EVOLUTION REACTION ON POROUS LANTHANUM-PHOSPHATE-BONDED NICKEL ELECTRODES

A steady-state method and ac impedance spectroscopy were used to inves tigate the hydrogen evolution reaction (HER) on porous lanthanum-phosp hate-bonded nickel (LPBN) electrodes in 9M NaOH and KOH solutions at t emperatures ranging from 20 to 70-degrees-C. The Tafel slopes, exchang e current densities, and overpotentials at a current density of 250 mA /cm2 were obtained from steady-state measurements. The ac,impedance da ta were analyzed using the porous-electrode model, and the kinetic par ameters of the HER and double-layer capacitances were determined. The pore length was deduced to be 64 to 73 mum compared to 1 mum for the d iameter. The effect of temperature and the nature of the electrolyte o n the intrinsic electrocatalytic activity of the LPBN electrodes are d iscussed.