Co-Ni-Mo as a Non-Noble Metal Electrocatalyst for Ethanol Electro-Oxidation

Abstract

Despite high electrocatalytic activity associated with platinum for electro-oxidation of ethanol, its easy deactivation by CO species and high cost motivates the evaluation of non-noble electrocatalysts for ethanol electro-oxidation. Trimetallic electrocatalyst containing Cobalt (Co), Nickel (Ni), and Molybdenum (Mo) was prepared through electroless deposition technique and evaluated for ethanol electro-oxidation. As-deposited Co-Ni-Mo electrocatalyst supported on Pd-catalyzed carbon substrate (CCS) was used and the effects of catalyst composition (correlated to electroless deposition time) and oxidation temperatures (30−60°C) were investigated. CV and potentiostatic techniques were used in the study. Tafel analysis showed that the exchange current density for the 30-minute deposited catalyst (1.3 × 10−5A/cm2) was an order of magnitude higher than that reported for Pt (0.001 × 10−5A/cm2,1), and Pt/C (0.033 × 10−5A/cm2,1) suggesting improved ability of the catalyst at handling CO deactivating species relative to Pt. The trimetallic catalyst showed very low onset potential (−0.39 V vs. Ag/AgCl). The linearity of the CV peak potential with the logarithm of scanning rates confirmed the irreversibility of ethanol electro-oxidation on the catalyst. The activation energy (Ea) and rate constant for the CoNiMo electrocatalysts were proposed and the effect of multi-metallic composition on the reaction investigated. Overall, this study provides a novel and effective non-noble electrocatalyst for ethanol electro-oxidation.