In situ activation of a Ni catalyst with Mo ion for hydrogen evolution reaction in alkaline solution

Abstract

In this study Ni catalyst have been activated during hydrogen evolution reaction (HER) by adding Mo ions into the alkaline electrolyte. After dissolving different amounts of ammonium molybdate in the 1M NaOH as electrolyte, Ni catalyst was used as cathode for HER. Afterwards a comparison between hydrogen overpotential measured in Ni catalyst with and without in situ activation has been made; the in situ activation shows an improvement of electrocatalytic properties of Ni catalyst for hydrogen evolution reaction. In the other words impact increase of in situ activation of Mo ions on the Ni structure, show that extremely significant impact in improving the Ni catalyst activation during in situ activation. The values of Tafel slope for Ni catalyst without Mo is an average of about 141 mVdec-1, while by using in situ activation by activator Mo ion this value is about 172 mVdec-1. As well as the values of overpotential for Ni catalyst, are an average of about 625 mV, by using in situ activation, these values are about 482 mV at the current density of 250 mAcm-2 (η250). In this study electrochemical data obtained from linear sweep voltammetry (LSV), the steady state polarization Tafel curves, electrochemical impedance spectroscopy (EIS).