Effect of Activation Degree of Resorcinol–Formaldehyde Carbon Gels on Carbon monoxide Tolerance of Platinum–Ruthenium Polymer Electrolyte Fuel Cell Anode Catalyst

Abstract

Resorcinol–formaldehyde carbon gels (RFCs) show several advantageous properties as a catalyst support over other carbons, as their pore volume and pore size can be readily tailored, for example, via CO2 activation. In this study, RFCs were synthesized with various activation degrees (burn-off) as 0, 37, 58, and 88% and used as the support for a PtRu anode electrode; a commercial Pt2Ru3/C anode catalyst was used as a reference. The catalysts were characterized by powder X-ray diffraction (PXRD), BET surface area, transmission electron microscopy (TEM), and scanning transmission electron microscopy (STEM). The performance and CO tolerance of the obtained catalysts were tested through single cell performance analysis with CO contaminations ranging from 100 to 2000 ppm. The prepared Pt2Ru3/RFC catalysts showed superior CO tolerance. Especially Pt2Ru3/RFC prepared using an RFC with a burn-off of 58% (RC1000Ac58) showed the highest performance and best CO tolerance. The activation degree could affect the volumes and sizes of mesopores and micropores, resulting in differences in size and dispersion of PtRu particles, and accessibility to the particles both of which govern the performance and CO tolerance of the catalysts. Pt2Ru3/RC1000Ac58 showed the highest cell voltage of 0.787 V and highest CO tolerance at 2000 ppm of CO (0.655 V, only 16.8% overvoltage). Supporting PtRu particles by using a carbon support with an optimum activation degree could be a practical method to improve the performance and CO tolerance of a PtRu electrocatalyst.