Synthesis of Core-shell Structured Ru@Pd/C Catalysts for the Electrooxidation of Formic Acid

Core-shell structured Ru@Pd/C catalysts for the electrooxidation of formic acid are synthesized by an organic colloid method associated with a pulse electrodeposition process. The catalysts are characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM) and X-ray photoelectron spectroscopy (XPS). The electrocatalytic activity of the catalysts is evaluated by cyclic voltammetry, CO stripping and chronoamperometry technologies. The core-shell structure is revealed by both materials characterization and electrochemical methods, including STEM and energy dispersive X-ray spectroscopy (EDX), the binding energy difference of the XPS spectra and the potential shift of the CO stripping peaks. Such core-shell structured Ru@Pd/C catalysts show excellent activity towards the anodic oxidation of formic acid. The mass activity reaches 5.06 A mg(Pd)(-1) and 0.53 A mg(metal)(-1) which are similar to 10.1 and 1.1 times that of commercial Pd/C. The encouraging performance of Ru@Pd/C is ascribed to the distinct dispersion of the Ru cores and the resulting Ru@Pd nanoparticles as well as the synergy between the core and shell that not only significantly enhances the ability to oxidize the formic acid but also improves the tolerance to CO. (C) 2017 Elsevier Ltd. All rights reserved.