Preparation of nanostructured Co–Mo alloy electrodes and investigation of their electrocatalytic activity for hydrazine oxidation in alkaline medium

Abstract

Cobalt and cobalt–molybdenum alloy electrodes are prepared by galvanic deposition on copper substrates. In this paper, we report a study on the influence of alloying cobalt with molybdenum for the oxidation of hydrazine in 1 M NaOH aqueous solutions. The electrocatalytic properties of the electrodes are studied by cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). Scanning electron microscopy (SEM), X‐ray diffraction (XRD), energy‐dispersive X‐ray spectroscopy (EDS,) and inductively coupled plasma (ICP) analysis demonstrate that the structural features and compositions of the as‐prepared Co–Mo coatings vary with the deposition conditions. Electrochemical characterization indicates that the electrochemical properties and the electrocatalytic activity of the investigated alloys were strongly dependent on the microstructural features obtained under different deposition conditions. The overall experimental data indicate that alloying cobalt with molybdenum metal leads to an increase of the electrocatalytic activity in hydrazine electroxidation compared to when using the pure cobalt electrode. High catalytic efficiencies were achieved on Co/25 at.% Mo and Co/33 at.% Mo electrodes, the latter being the best electrocatalyst for hydrazine electroxidation.