Highly active carbon nanotube-supported Ru@Pd core-shell nanostructure as an efficient electrocatalyst toward ethanol and formic acid oxidation

Herein, we report the facile synthesis of core-shell structured Ru@Pd/multi-walled carbon nanotube (MWCNT) catalyst via a two-step chemical reduction process without any surfactant and its electrocatalytic performance for ethanol and formic acid oxidation. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results revealed that the Ru@Pd nanoparticles are quite uniformly distributed on the surface of MWCNT with an average particle size of 2.3 nm. X-ray photoelectron spectroscopy (XPS) analysis showed the strong charge transfer interaction between Pd and Ru atoms on catalytic surface. The electrochemical studies demonstrated that the Ru@Pd/MWCNT catalyst exhibits higher peak current density and significantly enhanced long-term stability toward the anodic oxidation of ethanol in alkaline medium. Its electro-catalytic activity for ethanol oxidation is 1.8 and 2.7 times higher than that of Pd/MWCNT and commercial Pd/C catalysts, respectively, indicating the high utilization of Pd in as-prepared Ru@Pd/MWCNT catalyst. Moreover, the Ru@Pd/MWCNT also presents the enhanced electrocatalytic activity for formic acid oxidation (FAO) in acidic medium. This study opens up a new way for the fabrication of Pd-based electrocatalysts with high performance and low cost. (C) 2017 Elsevier B.V. All rights reserved.