Anode Catalyst of Hybrid AuPd and Rare Earth Doped Cerium Oxide/Multi-Walled Carbon Nanotubes for Direct Formic Acid Fuel Cells

Abstract

For the direct formic acid fuel cells, anodic Pd catalyst has attracted considerable attention recently. In order to enhance the catalytic ability, conductivity, and prevent from the catalyst poisoning, the synthesis of Au-Pd solid solution phase decorated on Ir or Ru doped CeO₂ modified MWCNTs substrate by polyol and synchrotron X-ray irradiation method were studied. The composition, structure and morphology were analyzed by XRD, SEM, TEM, TGA, and ICP, respectively. The hybrid AuPd/MOS/MWCNTs were not formed a single phase of AuPd in EG solution via polyol method but successfully synthesized in DI water solution by X-ray irradiation photochemical method at beam line 01A in Taiwan synchrotron radiation research center. The electrochemical analysis of AuPd series electrocatalysts via polyol method, AuPd/Ru_xCe_1−xO₂/MWCNTs have the highest electro-oxidizing current density in cyclic voltammetry experiment. However, Pd/CeO₂/MWCNTs have the lowest potential in the maximum electro-oxidizing current density. The results of ECSA indicate the AuPd/Ru_xCe_1−xO₂/MWCNTs have the highest electrocatalytic property. For the electrocatalysts synthesized via X-ray irradiation method (1A), AuPd/MWCNTs (1A) has the highest electro-oxidizing current density in cyclic voltammetry experiment meanwhile it has the lowest potential in the maximum electro-oxidizing current density. In addition, the results of ECSA indicate the AuPd/CeO₂/MWCNTs (1A) have the highest electrocatalytic property which AuPd/MWCNTs is almost matched with. Also, the results indicate Pd/CeO₂/MWCNTs (polyol) have the highest stability up to 10 k seconds with 250 mA/mg Pd current density.