The Use of the Heteropoly Acids, H3PMo12O40 and H3PW12O40, for the Enhanced Electrochemical Oxidation of Methanol for Direct Methanol Fuel Cells

Jack R. Ferrell, Mei Chen Kuo, John A. Turner, Andrew M. Herring

Research output: Contribution to journalArticlepeer-review

46 Scopus Citations

Abstract

Polarization and electrochemical impedance spectroscopy experiments were performed on a direct methanol fuel cell (DMFC) incorporating the heteropoly acids (HPAs) phosphomolybdic acid, H3PMo12O40, (HPMo) or phosphotungstic acid, H3PW12O40, (HPW) in the anode Pt/C catalyst layer. Both HPW-Pt and HPMo-Pt showed higher performance than the Pt control at 30 psig of backpressure and at ambient pressure. Anodic polarizations were also performed, and Tafel slopes were extracted from the data between 0.25 V and 0.5 V. At 30 psig, Tafel slopes of 133 mV/dec, 146 mV/dec, and 161 mV/dec were found for HPW-Pt, HPMo-Pt and the Pt control, respectively. At 0 psig, the Tafel slopes were 172 mV/dec, 178 mV/dec, and 188 mV/dec for HPW-Pt, HPMo-Pt and the Pt control. An equivalent circuit model, which incorporated constant phase elements (CPEs), was used to model the impedance data. From the impedance model it was found that the incorporation of HPAs into the catalyst layer resulted in a reduction in the resistances to charge transfer. This shows that these two heteropoly acids do act as co-catalysts with platinum for methanol electrooxidation.

Original languageAmerican English
Pages (from-to)4927-4933
Number of pages7
JournalElectrochimica Acta
Volume53
Issue number14
DOIs
StatePublished - 2008

NREL Publication Number

  • NREL/JA-560-43465

Keywords

  • Direct methanol fuel cell
  • Electrocatalysis
  • Heteropoly acid
  • PEM fuel cell

Fingerprint

Dive into the research topics of 'The Use of the Heteropoly Acids, H3PMo12O40 and H3PW12O40, for the Enhanced Electrochemical Oxidation of Methanol for Direct Methanol Fuel Cells'. Together they form a unique fingerprint.

Cite this