Voltage Oscillations in a Polymer Electrolyte Membrane Fuel Cell with Pd-Pt/C and Pd/C Anodes

Autor(es)

Nogueira, Jessica Alves ^[1] ; Varela, Hamilton ^[1]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Chem Sao Carlos, POB 780, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CHEMISTRYOPEN; v. 6, n. 5, p. 629-636, OCT 2017.
• Citações Web of Science: 1

Resumo

Polymer electrolyte membrane fuel cells (PEMFC) fed with H-2 contaminated with CO may exhibit oscillatory behavior when operated galvanostatically. The self-organization of the anodic overpotential is interesting because it can be accompanied by an increase in the average performance. Herein we report experimental studies of voltage oscillations that emerge in a PEMFC equipped with a Pd/C or PdPt/C anode and fed with H-2 contaminated with CO (100 ppm). We used on-line mass spectrometry to investigate how the mass fragments associated with CO2 and CO (m/z 44 and 28, respectively) varied with the voltage oscillations. Overall, we observed that oscillations in the anodic overpotential are in phase with that of the CO and CO, signals. This fact is consistent with an autonomous adsorption oxidation cyclic process. For both anodes, it has been observed that, in general, an increase in current density implies an increase in oscillatory frequency. By using CO stripping, we also discuss how the onset of CO oxidation is related to the maximum overpotential reached during a cycle, whereas the minimum overpotential can be associated with the catalytic activity of the electrode for H-2 oxidation. (AU)

• Processo FAPESP: 13/16930-7 - Eletrocatálise V: processos eletrocatalíticos de interconversão entre as energias química e elétrica
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• Processo FAPESP: 15/09295-9 - Comportamento dinâmico em células a combustível de baixa temperatura baseadas na oxidação de moléculas orgânicas pequenas
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• Processo FAPESP: 12/21204-0 - Auto-organização temporal na eletro-oxidação de moléculas orgânicas pequenas: efeito da estrutura da superfície, da concentração de água e da temperatura
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