The Effects of Multiple Contaminants on Polymer Electrolyte Fuel Cells

Abstract

Operating polymer electrolyte fuel cells (PEFC) on ultra high purity hydrogen (UHP) and clean air would be ideal. However, producing UHP H2 may be cost prohibitive and therefore tradeoffs between hydrogen clean up and fuel cell cost and durability need to be explored. Hydrogen for wide spread fuel cell commercialization will likely primarily come from reforming of fossil fuels, at least initially. The reformation of hydrocarbon fuels such as methane or coal produces impurities. The concentration and type depend on the fossil fuel and the reformation process. We have tested a fuel specification, listed in Table 1, provided by the US FreedomCar Tech Team as a function of different Pt anode loadings. These loadings were in line with the Department of Energy's 2010 and 2015 technical targets. Our findings indicate that NH3 and H2S are responsible for the majority of performance losses. We observed an increase in the high frequency resistance suggesting ammonium poisoning of the membrane, and cyclic voltammetry showed a large oxidation peak (>0.8V), which suggests sulfur poisoning of the anode. CO was not found on the surface at long exposure times.