Enhanced Electrocatalytic Oxidation of Ethylene Glycol on Au Nanoparticles Supported by Co₃O₄–CeO₂/Carbon Catalysts

The development of efficient and stable electrocatalysts for alcohol oxidation reactions is essential for advancing alkaline fuel cell technologies. In this study, Au-based catalysts supported on CeO₂/C and Co₃O₄–CeO₂/C mixed oxide systems were synthesized and evaluated for ethylene glycol oxidation in alkaline media. CeO₂ and Co₃O₄–CeO₂ mixed oxide supports were prepared via precipitation using Ce³⁺ and Co²⁺ precursors, followed by thermal treatment at 400 °C. Gold nanoparticles were deposited on the prepared supports through a microwave-assisted synthesis method. The obtained catalysts, namely AuCeO₂/C, AuCeO₂/C-T, AuCo₃O₄–CeO₂/C, and AuCo₃O₄–CeO₂/C-T, were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and inductively coupled plasma optical emission spectroscopy (ICP-OES). Their electrocatalytic properties toward ethylene glycol oxidation were investigated using cyclic voltammetry. The incorporation of Co₃O₄ and thermal treatment significantly improved catalytic performance. Among all investigated materials, AuCo₃O₄–CeO₂/C-T exhibited the highest activity, reaching a current density of 93.36 mA cm⁻² and an onset potential of −0.266 V vs. Ag/AgCl, compared with 36.58 mA cm⁻² and −0.174 V for AuCeO₂/C. The enhanced performance was attributed to stronger metal–support interactions and a higher density of active sites. All catalysts demonstrated favorable resistance to CO poisoning, with jF/jR values close to 3.0, where higher values indicate greater tolerance to surface poisoning. Kinetic analysis indicated a diffusion-controlled oxidation process dependent on both OH⁻ and ethylene glycol concentrations. The results demonstrate that combining Co₃O₄ with CeO₂/C supports and applying thermal treatment is an effective strategy for enhancing the activity and stability of Au-based electrocatalysts for ethylene glycol oxidation in alkaline media.