Electrocatalytic activities of macro- Porous nickel electrode for hydrogen evolution reaction in alkaline media

Abstract

ALKALINE water electrolysis is one of the easiest methods for hydrogen production, offering the advantages of simplicity, high purity and low cost. Nickel and other transition metal such as (Ni, Co, Fe and Mo) 3 D porous foams are an exciting family of catalysts for hydrogen production in alkaline electrolytes because of their special corrosion resistance and highly intrinsic electrocatalytic activity toward HER. In this work, macro porous Ni electrodes have been developed by dynamic hydrogen template electrodeposition (DHTE) on stainless steel (AISI 304) substrates. Macro porous Ni electrodes with pore size ranging for 1.3-9.41 µm were synthesized by galvanostatic deposition at high current densities. Higher current density and longer deposition time lead to coarsening of pore size obtained. On the other hand, increasing the concentration of NH4Cl additives lead to a remarkable reduction in pore size. The activity for hydrogen evolution reaction (HER) on the obtained layers was evaluated by using potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) in 10 % KOH solution. The electrochemical tests results showed that Ni deposit with fine pore size (1.7 µm) manifests the highest intrinsic activity for HER.