Effect of current pulsing and “self-oxidation” on the CO tolerance of a PEM fuel cell

Thomason, A.H.; Lalk, T. R.; Appleby, A.J.

doi:10.1016/j.jpowsour.2004.03.070

Cited by 43 publications

(29 citation statements)

References 4 publications

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“…The adsorbed CO is then electrochemically oxidised on the anode catalyst surface above a certain limiting overpotential. This in turn releases the active sites earlier occupied by CO [10,[20][21][22][23]. The simple dynamic modelling proposed by Zhang and Datta [10] was mainly based on this mechanism and was able to successfully describe most experimental observations.…”

Section: The Influence Of the Current Density On Potential Oscillationsmentioning

confidence: 99%

Dynamic Behavior of a PEM Fuel Cell During Electrochemical CO Oxidation on a PtRu Anode

et al. 2008

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The dynamic behaviour of a single PEM fuel cell (PEMFC) with a PtRu/C anode catalyst using CO containing H 2 as anode feed was investigated at ambient temperature. The autonomous oscillations of the cell potential were observed during the galvanostatic operation with hydrogen anode feed containing CO up to 1000 ppm. The oscillations were ascribed to the coupling of the adsorption of CO (the poisoning step) and the subsequent electrochemical oxidation of CO (the regeneration step) on the anode catalyst. The oscillations were dependent on the CO concentration of the feed gas and the applied current density. Furthermore, it was found that with CO containing feed gas, the time average power output was remarkably higher under potential oscillatory conditions in the galvanostatic mode than during potentiostatic operation. Accompanying these self-sustained potential oscillations, oscillation patterns of the anode outlet CO concentration were also detected at low current density (\100 mA/cm 2 ). The online measurements of the anode outlet CO concentrations revealed that CO in the anode CO/H 2 feed was partially electrochemically removed during galvanostatic operation. More than 90% CO conversion was obtained at the current densities above 125 mA/cm 2 with low feed flow rates (100-200 mL/min).

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Section: The Influence Of the Current Density On Potential Oscillationsmentioning

confidence: 99%

Dynamic Behavior of a PEM Fuel Cell During Electrochemical CO Oxidation on a PtRu Anode

et al. 2008

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“…The potential oscillations, instabilities and steadystate multiplies have also been observed and simulated in PEMFCs, which are resulted generally from dynamic CO poisoning/reactivating, mass transfer limitation, and/or reactant concentration gradients. [16][17][18][19][20][21][22][23][24][25][26][27] However, there is still limited work done so far on the potential oscillations in the PEMFCs with CO-containing H 2 feed for understanding the complicated processes.…”

Section: Introductionmentioning

confidence: 99%

Spontaneous oscillations of cell voltage, power density, and anode exit CO concentration in a PEM fuel cell

Lü¹,

Rihko‐Struckmann²,

Sundmacher³

2011

Phys. Chem. Chem. Phys.

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The spontaneous oscillations of the cell voltage and output power density of a PEMFC (with PtRu/C anode) using CO-containing H 2 streams as anodic fuels have been observed during galvanostatic operating. It is ascribed to the dynamic coupling of the CO adsorption (poisoning) and the electrochemical CO oxidation (reactivating) processes in the anode chamber of the single PEMFC. Accompanying the cell voltage and power density oscillations, the discrete CO concentration oscillations at the anode outlet of the PEMFC were also detected, which directly confirms the electrochemical CO oxidation taking place in the anode chamber during galvanostatic operating.

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“…The reason for this is seen in the asymmetry of the voltage oscillations . In a subsequent study, Thomason et al (2004) brought the fi ndings of in context with methods to increase the CO tolerance of PEMFCs, such as air bleed (e.g., Gottesfeld and Pafford 1988 ), current pulsing (e.g., Carrette et al 2001 ), and Figure 12 Diagram taken from Hanke -Rauschenbach et al (2010) illustrating the behavior of the spatially distributed system for low feed fl ow rates: (A) temporal evolution of the cell voltage U cell ( t ); spatiotemporal evolution of the (B) anode double layer potential ∆ ϕ ( z , t ); (C) CO surface coverage θ CO (z, t ); (D) local anodic current density i a ( z , t ), and (E) CO mole fraction in the gas channel x CO (z, t ). Reproduced from Hanke -Rauschenbach et al (2010) by permission of ECS -The Electrochemical Society.…”

Section: Technical Applicationsmentioning

confidence: 86%

Nonlinear dynamics of fuel cells: a review

Hanke‐Rauschenbach

Mangold

Sundmacher³

2011

Reviews in Chemical Engineering

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Over the last decade, nonlinear phenomena in low-temperature fuel cells as well as high-temperature fuel cells have been reported in the open literature. Experimental and theoretical studies found multiple steady states as well as periodic oscillations. The present article gives an overview of publications on this subject. Instead of sorting the analyses according to the types of fuel cells, this work used the source of the nonlinearity for classifi cation. In the fi rst part of the contribution, a very simple prototype fuel cell model is introduced. The model helps to give a qualitative explanation of the majority of nonlinear effects reported in literature. It is further used to identify potential sources of nonlinear behavior in reaction kinetics, membrane properties, and mass transport mechanisms. A classifi cation scheme that is based on types of negative differential resistance (NDR) and was originally introduced by K. Krischer in Modern Aspects of Electrochemistry (Vol. 32, p. 1, Plenum Press, 1999) for electrochemical systems is applied to fuel cells. The second part of the work classifi es the fi ndings from literature according to their NDR type. Instabilities resulting not from electrochemistry but from other mechanisms such as water formation and reactant starvation are also discussed.

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Effect of current pulsing and “self-oxidation” on the CO tolerance of a PEM fuel cell

Cited by 43 publications

References 4 publications

Dynamic Behavior of a PEM Fuel Cell During Electrochemical CO Oxidation on a PtRu Anode

Dynamic Behavior of a PEM Fuel Cell During Electrochemical CO Oxidation on a PtRu Anode

Spontaneous oscillations of cell voltage, power density, and anode exit CO concentration in a PEM fuel cell

Nonlinear dynamics of fuel cells: a review

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