Preparation of CeO2-doped graphene supported platinum catalysts for enhanced methanol oxidation and oxygen reduction reactions

Abstract This study presents a systematic investigation of CeO 2 -doped reduced graphene oxide (RGO) as a support for platinum catalysts in direct methanol fuel cells. CeO 2 /RGO composites with loadings of 3–10 wt% CeO 2 were synthesized via controlled precipitation and thermal reduction, followed by the deposition of Pt nanoparticles using ascorbic acid as a reducing agent. Physical characterization by XRD, TEM, and XPS confirmed the uniform dispersion of Pt nanoparticles (3–4 nm) and revealed chemical interactions between Pt and CeO 2 . Electrochemical testing demonstrated that the catalyst with 5% CeO 2 doping exhibited optimal performance: A methanol oxidation current of 959 mA/mgPt, which is four times higher than that of the undoped Pt/RGO benchmark. An electrochemical surface area (ECSA) of 87.1 m 2 /g. Enhanced CO tolerance, as indicated by an If/Ib ratio of 1.24. The enhanced catalytic activity is attributed to the oxygen storage capacity of CeO 2 and synergistic interfacial effects between Pt and CeO 2 , which were evidenced by a positive shift in the Pt4f binding energy observed in XPS analysis. This work demonstrates a cost-effective strategy for improving Pt utilization in fuel cell anodes through doping with rare earth oxides.