Mg-Ca-Fe layered double hydroxide-gold nanoparticles as an efficient electrocatalyst for ethanol oxidation

In this work, the influence of Mg-Ca-Fe layered double hydroxide (LDH) on the electrocatalytic activity of gold nanoparticles (AuNPs) electrodeposited on a glassy carbon electrode for ethanol oxidation in alkaline medium was investigated. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FE-SEM) and cyclic voltammetry (CV) were used to characterize the synthesized Mg-Ca-Fe LDH powder and to investigate the electrochemical behaviors of the prepared electrodes. The results showed that the AuNPs/GCE exhibits higher current density for ethanol oxidation (about 2.9 times) and higher active surface area (about 2.5 times), after the deposition of the Mg-Ca-Fe LDH on its surface. It was also found that the ethanol oxidation reaction at the LDH/AuNPs/GCE is an adsorption-controlled process, while at the AuNPs/GCE it is a diffusion-controlled process. The investigation of the long-term stability of the electrodes using CV and chronoamperometry methods indicated that the Mg-Ca-Fe LDH by providing OHads species at the surface of the catalyst improves the endurance of the AuNPs against poisoning effects of intermediate species. Accordingly, the Mg-Ca-Fe LDH can be used to improve the electrocatalytic performance of supported AuNPs in the anode of alkaline ethanol fuel cells. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.