Improved catalytic activity of MoxNiyAlz thin films as electrocatalyst for hydrogen evolution reaction in alkaline media

Abstract

In this work, we report activities of MoxNiyXz (where X is Al, Co, Cr, Cu, Fe, W)-based electrocatalysts for hydrogen evolution reaction (HER) in a 1 M NaOH solution. MoxNiyXz thin film electrocatslysts were prepared by magentron sputtering at 25 °C and 800 °C and characterized by scanning electron microscopy (SEM) with energy dispersive X-ray (EDX) analyzer and X-ray diffraction (XRD) analysis. The catalytic activity of electrocatalyst was studied by cyclic voltammetry and electrochemical impedance spectroscopy. The electrocatalyst based on Mo80Ni5Al15(800 °C) shows the best value of the overpotential (−181 mV) for HER from all tested ternary systems. XRD analysis indicates that HER activity only Mo80Ni5Al15 thin films prepared at 800 °C contained fcc phase. Other less active composition contained only bcc phase. The results obtained from impedance spectroscopy are consistent with the results from cyclic voltammetry. The stability of the prepared catalyst was studied by chronoamperometric analysis. The results from chronoamperometry show that HER activity of Mo80Ni5Al15 prepared at 800 °C, after very slight initial activity decrease, stays constant, while activity of Ni catalyst decreased almost twice in measured time window. Since Ni is commonly used industrial catalyst, Mo80Ni5Al15 based alloy could be more attractive catalyst material for alkaline electrolyzers.