Synthesis of nano-Co3O4-based electrocatalysts and their performance in direct methanol fuel cells

Abstract

This study reports the synthesis of nano-Co3O4 catalysts with tailored size and morphology using PEG as a dispersant, optimizing their application in DMFCs. By varying the molecular weight of PEG (400, 800, and 20000), the Co3O4 catalysts exhibited distinct structural and catalytic properties. The Co3O4 synthesized with PEG20000 showed the smallest crystallite size of 19.8 nm, the highest BET surface area of 168.7 m2 /g, and a uniform morphology with well-dispersed nanoscale particles. Electrochemical analysis revealed that the Co3O4- modified Pt/C catalyst prepared with PEG20000 achieved a peak current density of 1.58 mA/cm2 . The catalyst also demonstrated an onset potential of 0.19 V and a stability retention of 78.6% after 400 s of operation, outperforming Pt/C (68.4%). These enhancements are attributed to the synergistic effect providing oxygen species for intermediate oxidation and mitigating CO poisoning. The findings highlight the potential of Co3O4-modified Pt/C catalysts as efficient, cost-effective alternatives for DMFCs, with superior catalytic activity, stability, and methanol tolerance. This work offers insight into the role of dispersants in tailoring catalyst properties for energy applications.