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 (Co 3 O 4 ) with carbon derived from neem leaves (NC), forming a Co 3 O 4 @NC composite. The Co 3 O 4 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 Co 3 O 4 @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/cm 2 , the Co 3 O 4 @NC catalyst delivered a maximum power density of 42.60 mW/cm 2 . These findings demonstrate the potential of Co 3 O 4 @NC, derived from a renewable biomass source, as a promising and sustainable alternative to expensive platinum-based catalysts for ORR applications. • Sustainable and cost-effective Co 3 O 4 @NC catalyst for oxygen reduction reaction. • Comparable Electrochemical Performance to Pt/C. • Renewable biomass source as a carbon precursor. • A maximum power density of 42.60 mW/cm 2 at a mass loading of 1 mg/cm 2 . • Potential for practical applications in anion exchange membrane fuel cells.