CoNi₂O₄/MWCNT: A promising anode catalyst for direct alcohol fuel cells

This study presents a highly efficient bifunctional electrocatalyst, CoNi₂O₄/MWCNT, comprising porous cobalt-nickel binary oxide (CoNi₂O₄) uniformly integrated with multi-walled carbon nanotubes (MWCNT), designed for anodic methanol and ethanol oxidation in direct alcohol fuel cells (DAFCs). The porous CoNi₂O₄ was synthesized through a simple, one-step hydrothermal route. Detailed physicochemical characterization confirmed its spinel structure, high surface area, and intimate interfacial contact with the MWCNT support. Electrochemical evaluations revealed excellent catalytic performance, delivering peak current densities of approximately 130 mA.cm⁻² for methanol oxidation and 48 mA.cm⁻² for ethanol oxidation at a scan rate of 100 mV.s⁻¹. The composite also demonstrated remarkable long term stability, retaining 93.5% and 89.9% of its initial activity after 1000 cyclic voltammetry cycles for methanol and ethanol oxidation, respectively. Tafel slopes of 90.4 mV.dec⁻¹ (methanol) and 74.9 mV.dec⁻¹ (ethanol) indicate fast charge transfer kinetics, comparable to or surpassing many state of the art noble metal free catalysts. This work introduces a scalable, noble metal free catalyst that simultaneously achieves high activity and exceptional durability for both methanol and ethanol oxidation, offering a promising and cost effective alternative to platinum-based anodes in practical DAFC systems. These results highlight the potential of CoNi₂O₄/MWCNT as a high performance, durable anode material for next-generation direct alcohol fuel cells.