Development of Ni-Mo, Ni-W and Ni-Co Macroporous Materials for Hydrogen Evolution Reaction

Abstract

The hydrogen evolution reaction (HER) is the cathodic process in many important electrochemical technologies. According to the Brewer intermetallyc bonding theory, molybdenum and tungsten were alloyed with nickel (hypo-hyper-d- electronic transition metal) in order to increase the intrinsic catalytic activity for HER. Cobalt was also combined with nickel to evaluate the effect of this metal in the intrinsic catalytic activity. In all the cases, electrodeposition at very high current densities provided macroporous materials of quasy-cylindrical pores due to the fact that the metallic deposition takes place simultaneously to the gas bubbling at high current densities. Morphology of the developed electrodes was characterized by confocal laser scanning microscopy, and HER on these electrodes was evaluated in 30 wt.% KOH solution by means of steady-state polarization curves and electrochemical impedance spectroscopy (EIS). Results show that the developed materials manifest higher apparent catalytic activity than that reported for a smooth commercial polycrystalline nickel electrode.