Polydopamine functionalized multi-walled carbon nanotubes supported PdAu nanoparticles as advanced catalysts for ethylene glycol oxidation

Abstract

Design of high performance and low cost electrocatalysts for the oxidation of small organic molecules remains a great challenge for the practical application of direct fuel cells. Herein, a novel composite catalyst composed of PdAu nanoparticles (NPs) uniformly dispersed on the polydopamine functionalized MWCNTs (PDA-MWCNTs) has been synthesized. TEM images indicate that MWCNTs are successfully coated by PDA, and the as-prepared PdAu NPs are homogeneously dispersed on the PDA functional MWCNTs with smaller sizes than those on pristine MWCNTs. Electrochemical tests reveal that PDA-MWCNTs is a promising catalyst carrier for direct ethylene glycol fuel cell (DEGFC), and the PdAu(1:1)/PDA-MWCNTs catalyst displays the highest peak current density among all catalysts towards ethylene glycol oxidation reaction (EGOR) in alkaline medium, with mass activity of 1540.3 mA mgPd−1, which is 1.5, 2.6, 9.8, 13.4 and 2.0 times greater than those of PdAu(1:3)/PDA-MWCNTs, PdAu(3:1)/PDA-MWCNTs, Pd/PDA-MWCNTs, Pd/MWCNTs and commercial Pd/C catalysts, respectively. In addition, PdAu(1:1)/PDA-MWCNTs catalyst also exhibits the best stability. These findings are valuable for the development of advanced Pd-based catalysts, which will help promote the industrialization of direct fuel cell.