Membrane Degradation Mechanisms in PEMFCs

Nafion membrane degradation was studied in a polymer electrolyte membrane fuel cell (PEMFC) under accelerated decay conditions. Fuel cell effluent water was analyzed to determine the fluoride emission rate. Experimental findings show that formation of active oxygen species from H 2 O 2 decomposition or the direct formation of active oxygen species in the oxygen reduction reaction are not the dominating membrane degradation mechanisms in PEMFCs. Instead, membrane degradation occurs because molecular H 2 and O 2 react on the surface of the Pt catalyst to form the membrane-degrading species. The source of H 2 or O 2 is from reactant crossover through the membrane. The reaction mechanism is chemical in nature and depends upon the catalyst surface properties and the relative concentrations of H 2 and O 2 at the catalyst. The membrane degradation rate also depends on the residence time of active oxygen species in the membrane and volume of the membrane. The sulfonic acid groups in the Nafion side chain are key to the mechanism by which radical species attack the polymer.

[1]  Hubert A. Gasteiger,et al.  Oxygen reduction reaction on Pt(111): effects of bromide , 1999 .

[2]  Shulamith Schlick,et al.  Membrane-derived fluorinated radicals detected by electron spin resonance in UV-irradiated Nafion and Dow ionomers: effect of counterions and H2O2. , 2005, The journal of physical chemistry. B.

[3]  C. Walling.  Fenton's reagent revisited , 1975 .

[4]  Minoru Inaba,et al.  Durability of perfluorinated ionomer membrane against hydrogen peroxide , 2006 .

[5]  E. Fridell,et al.  An experimental study of the kinetics of OH and H2O formation on Pt in the H2 + O2 reaction , 1989 .

[6]  Fuqiang Liu,et al.  Degradation mechanism of polystyrene sulfonic acid membrane and application of its composite membranes in fuel cells , 2003 .

[7]  M. De Francesco,et al.  Nafion degradation in PEFCs from end plate iron contamination , 2003 .

[8]  M. Hein,et al.  In-situ spin trap electron paramagnetic resonance study of fuel cell processes , 2004 .

[9]  D. Wilkinson,et al.  Degradation of polymer electrolyte membranes , 2006 .

[10]  Danzhen Li,et al.  Promoting effects of H2 on photooxidation of volatile organic pollutants over Pt/TiO2 , 2005 .

[11]  James M. Fenton,et al.  Is H2O2 Involved in the Membrane Degradation Mechanism in PEMFC , 2006 .

[12]  N. Alonso‐Vante,et al.  Novel low-temperature synthesis of semiconducting transition metal chalcogenide electrocatalyst for multielectron charge transfer: molecular oxygen reduction , 1994 .

[13]  I. Tabushi,et al.  P-450-tpye dioxygen activation using hydrogen/colloidal platinum as an effective electron donor , 1981 .

[14]  S. Srinivasan,et al.  Quantum jumps in the PEMFC science and technology from the 1960s to the year 2000 Part I. Fundamental scientific aspects , 2001 .

[15]  Hubert A. Gasteiger,et al.  Handbook of fuel cells : fundamentals technology and applications , 2003 .

[16]  D. Wilkinson,et al.  Current status of ab initio quantum chemistry study for oxygen electroreduction on fuel cell catalysts , 2006 .

[17]  James M. Fenton,et al.  Effect of Catalyst Properties on Membrane Degradation Rate and the Underlying Degradation Mechanism in PEMFCs , 2006 .

[18]  Minoru Inaba,et al.  Gas crossover and membrane degradation in polymer electrolyte fuel cells , 2006 .

[19]  D. Curtin,et al.  Advanced materials for improved PEMFC performance and life , 2004 .