Solid acid fuel cells based on CsH2PO4 as the solid state electrolyte operate at ca. 240°C and are currently performance limited at the cathode. Here, vulcan carbon has been mainly used as an electronic interconnect and catalyst support.2 Recently, carbon nanotubes have been employed, increasing the mass normalized activity of the Pt catalyst up to 61 S/mgPt.3,4
Here we combine the benefits of recent findings and present new fabrication routes based on spraydrying, metal-organic chemical vapor deposition to create highly active, nanostructured composite electrode materials, based on Pt decorated CNTs and graphene. In addition, we evaluate the suitability of surface functionalized carbon nanomaterials as precious metal free catalyst in solid acid fuel cell cathodes. Functionalization includes plasma treatment and electron beam irradiation under controlled atmospheres. Raman and XPS analysis is used before and after electrochemical measurements to evaluate structural and chemical changes. Data from impedance spectroscopy of symmetric electrochemical cells suggest effective electrochemical activity of CNTs and graphene in solid acid fuel cell cathodes.
(1) Gong, K.; Du, F.; Xia, Z.; Durstock, M.; Dai, L. Science 2009, 323, 760.
(2) Chisholm, C. R. I.; Boysen, D. A.; Papandrew, A. B.; Zecevic, S. K.; Cha, S.; Sasaki, K. A.; Varga, Á.; Giapis, K. P.; Haile, S. M. Interface Magazine 2009, 18, 53.
(3) Varga, Á.; Pfohl, M.; Brunelli, N. A.; Schreier, M.; Giapis, K. P.; Haile, S. M. Physical chemistry chemical physics : PCCP 2013, 15, 15470.
(4) Thoi, V. S.; Usiskin, R. E.; Haile, S. M. Chem. Sci. 2015, 6, 1570.