Nanostructured Catalysts Synthesized by High-Energy Mechanical Alloying for Formic Acid Electrochemical Oxidation

Abstract

Formic acid (FA) oxidation at Pd-X (where, X is cobalt or nickel) nanostructures synthesized by high-energy mechanical alloying (MA) was reported. The structure and morphology of Pd-X were characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). It was found that Pd-Co was comprised mainly by the intermetallic Pd2Co formation while Pd-Ni by the alloy Ni0.525Pd0.475. Both catalysts exhibit lamellar agglomerates that were nanostructurated in nature (with crystallite sizes between 2 and 17 nm). The electrochemically active surface area of both catalysts was determined by CO stripping and the electrochemical results (cyclic voltammetry and chronoamperometry) demonstrated that Pd-Co and Pd-Ni displayed adequate catalytic activity towards FA oxidation reaction comparable to other systems reported in the literature including single metal, bimetallic, and trimetallic catalysts synthesized and supported differently.