Preparation of Nanostructured Pd-C-Ru Composite Electrodes for Alcohol Electrooxidations. Part-II: A Study of Methanol Oxidation by Cyclic Voltammetry and Impedance Spectroscopy

ABSTRACT

Ternary nanocomposites of Pd, Ru and nanocarbon (NC) have been prepared by the sodium borohydride reduction method and investigated by cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry techniques for their use as electrocatalysts for the methanol oxidation reaction (MOR). The study have shown that with addition of ruthenium from 1 to 50wt %, in the Pd-0.5wt %C composite, the rate of MOR initially increases, attains maximum and declines thereafter. Among ternary composites investigated, the Pd-0.5wt % C-20wt % Ru composite exhibited the greatest electrocatalytic activity. This electrode has approximately three times higher electrocatalytic activity than the base electrode (Pd-0.5wt % C). The electrochemical active surface area (≈ 133 m2/gPd) and the percentage utilization of Pd (30%) of the Pd-0.5wt % C-20wt % Ru electrode were also more than 5 times higher than that of the base electrode.