Co-deposition of Pt and ceria anode catalyst in supercritical carbon dioxide for direct methanol fuel cell applications

• Published in: Electrochimica acta 2012-07, Vol.75, p.191-200
• Main Authors: You, Eunyoung, Guzmán-Blas, Rolando, Nicolau, Eduardo, Aulice Scibioh, M., Karanikas, Christos F., Watkins, James J., Cabrera, Carlos R.
• Format: Article
• Language: English
• Subjects: Applied sciences; Carbon dioxide; Catalysts; Deposition; Direct methanol fuel cell; Electrodes; Energy; Energy. Thermal use of fuels; Equipments for energy generation and conversion: thermal, electrical, mechanical energy, etc; Exact sciences and technology; Fuel cells; Gas diffusion; Methanol oxidation; Methyl alcohol; Platinum; Platinum-ceria; Scanning electron microscopy; Supercritical fluid deposition; Thin-layer electrode
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2012.04.091

Pt and mixed Pt-ceria catalysts were deposited onto gas diffusion layers using supercritical fluid deposition (SFD) to fabricate thin layer electrodes for direct methanol fuel cells. Dimethyl (1,5-cyclooctadiene) platinum (II) (CODPtMe2) and tetrakis (2,2,6,6-tetramethyl 3,5-heptanedionato) cerium (IV) (Ce(tmhd)4) were used as precursors. Hydrogen-assisted Pt deposition was performed in compressed carbon dioxide at 60°C and 17.2MPa to yield high purity Pt on carbon-black based gas diffusion layers. During the preparation of the mixed Pt-ceria catalyst, hydrogen reduction of CODPtMe2 to yield Pt catalyzed the deposition of ceria from Ce(tmhd)4 enabling co-deposition at 150°C. The catalyst layers were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and scanning electron microscope-energy dispersive spectral (SEM-EDS) analyses. Their electrochemical performance toward methanol oxidation was examined in half cell mode using a three electrode assembly as well as in fuel cell mode. The thin layer electrodes formed via SFD exhibited higher performance in fuel cell operations compared to those prepared by the conventional brush-paint method. Furthermore, the Pt-ceria catalyst with an optimized composition exhibited greater methanol oxidation activity than pure platinum.