Improved performance of proton exchange membrane fuel cells with p-toluenesulfonic acid-doped co-PPy/C as cathode electrocatalyst.

A novel catalyst, Co-PPy-TsOH/C, for oxygen reduction reaction (ORR) in proton exchange membrane fuel cells (PEMFCs) was prepared by pyrolyzing cobalt salt and p-toluenesulfonic acid (TsOH)-doped polypyrrole-modified carbon support in an inert atmosphere. The characteristics and electrocatalytic activities of Co-PPy-TsOH/C were analyzed with various techniques, including Raman spectroscopy, elemental analysis, rotating ring disk electrode analysis, and a single H(2)-O(2) PEMFC, and compared with those of undoped catalyst Co-PPy/C. The results showed that doping TsOH introduces larger N and S contents in Co-PPy-TsOH/C, leading to much better electrocatalytic performance for ORR than Co-PPy/C, and that Co-PPy-TsOH/C is more likely to follow a four-electron-transfer reaction to reduce oxygen directly to H(2)O. The performance of PEMFCs with Co-PPy-TsOH/C as cathode catalyst is better than that with Co-PPy/C, and the resulting maximum output power density of 203 mW cm(-2) is a substantial improvement over the best values reported in the literature with Co-PPy/C-based cathode catalyst. This implies that doping TsOH is a valuable method to improve the catalytic activity of Co-PPy/C and that Co-PPy-TsOH/C is a promising cathode catalyst for PEMFCs. The function and mechanism of doping have also been analyzed and the configurations of PPy-TsOH/C and Co-PPy-TsOH/C proposed.

[1]  Y. Fujii,et al.  Raman spectra of polypyrrole and its 2,5-13C-substituted and C-deuterated analogues in doped and undoped states , 1988 .

[2]  Lei Zhang,et al.  Progress in preparation of non-noble electrocatalysts for PEM fuel cell reactions , 2006 .

[3]  S. Marcotte,et al.  Oxygen Reduction Catalysts for Polymer Electrolyte Fuel Cells from the Pyrolysis of Iron Acetate Adsorbed on Various Carbon Supports , 2003 .

[4]  Piotr Zelenay,et al.  A class of non-precious metal composite catalysts for fuel cells , 2006, Nature.

[5]  Lei Zhang,et al.  Ultrasonic spray pyrolyzed iron-polypyrrole mesoporous spheres for fuel celloxygen reduction electrocatalysts , 2009 .

[6]  Frédéric Jaouen,et al.  Iron-Based Catalysts with Improved Oxygen Reduction Activity in Polymer Electrolyte Fuel Cells , 2009, Science.

[7]  I. Orgzall,et al.  Raman spectroscopy of conducting polypyrrole under high pressure , 2002 .

[8]  Edmar P. Marques,et al.  A review of Fe-N/C and Co-N/C catalysts for the oxygen reduction reaction , 2008 .

[9]  Michel Lefèvre,et al.  Fe-based electrocatalysts made with microporous pristine carbon black supports for the reduction of oxygen in PEM fuel cells , 2008 .

[10]  K. Oyaizu,et al.  Modifying carbon particles with polypyrrole for adsorption of cobalt ions as electrocatatytic site for oxygen reduction , 2005 .

[11]  Lei Zhang,et al.  Oxygen reduction reaction (ORR) catalyzed by carbon-supported cobalt polypyrrole (Co-PPy/C) electrocatalysts , 2009 .

[12]  Sundara Ramaprabhu,et al.  Cobalt-polypyrrole-multiwalled carbon nanotube catalysts for hydrogen and alcohol fuel cells , 2008 .

[13]  R. Murray,et al.  Direct current redox versus electronic conductivity of the ladder polymer poly(benzimidazobenzophenanthroline) , 1988 .

[14]  B. Popov,et al.  Studies on Co-based catalysts supported on modified carbon substrates for PEMFC cathodes , 2006 .

[15]  Sanju Gupta.  Hydrogen bubble‐assisted syntheses of polypyrrole micro/nanostructures using electrochemistry: structural and physical property characterization , 2008 .

[16]  S. Demoustier‐Champagne,et al.  Effect of Electrolyte Concentration and Nature on the Morphology and the Electrical Properties of Electropolymerized Polypyrrole Nanotubules , 1999 .

[17]  Lei Zhang,et al.  A review of heat-treatment effects on activity and stability of PEM fuel cell catalysts for oxygen reduction reaction , 2007 .