Neem-derived carbon-cobalt oxide composite (Co3O4@NC): A sustainable and cost-effective catalyst for oxygen reduction in fuel cells

This study introduces a cost-effective and sustainable oxygen reduction reaction (ORR) catalyst by integrating cobalt oxide nanoparticles (Co₃O₄) with carbon derived from neem leaves (NC), forming a Co₃O₄@NC composite. The Co₃O₄ nanoparticles were synthesized via a hydrothermal method, and the composite was thoroughly characterized using X-ray diffraction, transmission electron microscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, and thermogravimetric analysis. Electrochemical evaluation in anion exchange membrane fuel cells revealed that the Co₃O₄@NC catalyst exhibits comparable performance to a commercial 40 wt% Pt/C catalyst, achieving an open circuit potential of 0.93 V versus 0.96 V for Pt/C. At a mass loading of 1 mg/cm², the Co₃O₄@NC catalyst delivered a maximum power density of 42.60 mW/cm². These findings demonstrate the potential of Co₃O₄@NC, derived from a renewable biomass source, as a promising and sustainable alternative to expensive platinum-based catalysts for ORR applications.