Outstanding Catalyst Performance of PdAuNi Nanoparticles for the Anodic Reaction in an Alkaline Direct Ethanol (with Anion-Exchange Membrane) Fuel Cell

Abstract

The present article deals with the comprehensive electrocatalytic study of the binary and ternary combinations of Ni and Au with Pd for use as the anode component of a direct ethanol fuel cell (DEFC) operating with an anion-exchange membrane (AEM). The catalysts were grown on a carbon support by chemical reduction of the respective precursors. The information on surface morphology, structural characteristics, and bulk composition of the catalyst was obtained using transmission electron microscopy, X-ray diffraction, and energy-dispersive X-ray spectroscopy. Brunauer–Emmett–Teller (BET) surface area and the pore widths of the catalyst particles were calculated by applying the BET equation to the adsorption isotherms. The electrochemical techniques like cyclic voltammetry, chronoamperometry, and impedance spectroscopy were employed to investigate the electrochemical parameters related to electro-oxidation of ethanol in alkaline pH on the catalyst surfaces within the temperature range 20–80 °C. The results show that the use of the ternary PdAuNi catalyst at the anode of an in-house fabricated DE­(AEM)­FC can increase the peak power density by more than 175% as compared with the use of the monometallic Pd catalyst, 108% as compared with the use of the bimetallic PdNi catalyst, and 42% as compared with the use of the bimetallic PdAu catalyst. The higher yield of the reaction products CH₃CO₂^– and CO₃^2– on the PdAuNi catalyst compared to its single and binary counterparts in alkaline medium, as estimated by ion chromatography, further substantiates the catalytic superiority of the PdAuNi catalyst to a remarkable extent over the other catalysts studied