A review on durability issues and restoration techniques in long-term operations of direct methanol fuel cells

Mehmood, Asad; Scibioh, M. Aulice; Prabhuram, Joghee; An, Myunggi; Ha, Heung Yong

doi:10.1016/j.jpowsour.2015.07.094

Cited by 127 publications

(76 citation statements)

References 175 publications

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“…[1][2][3][4][5] Direct methanol fuel cells (DMFC) with polymer electrolyte membranes (PEM) are already well developed and have achieved small scale commercialization. [6][7][8] Direct ethanol fuel cells (DEFC) are more attractive for sustainable energy production. 9,10 However, although there have been a number of demonstration projects, 6,10 performances are not yet sufficient for commercialization.…”

mentioning

confidence: 99%

Kinetics and Stoichiometry of Methanol and Ethanol Oxidation in Multi-Anode Proton Exchange Membrane Cells

Brueckner

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2017

J. Electrochem. Soc.

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The anode catalyst of a direct alcohol fuel cell (DAFC) influences its energy efficiency through both its effect on the cell potential and the reaction stoichiometry (average number of electrons released per fuel molecule; n av ). A method for determining these parameters simultaneously from a polarization curve (current vs. cell potential) is reported and various catalysts have been evaluated in a multi-anode cell. The cell was operated in crossover mode, in which fuel flows though the cathode chamber and diffuses though the membrane to be oxidized at the anode, to provide controlled mass transport conditions. Tafel analysis at low potentials provides kinetic information, while currents at high potentials provide n av values and their potential dependence. The method allows a number of catalysts to be compared under the same conditions, and provides characteristic parameters that could be compared across research groups. It is shown that while PtRu alloy catalysts provide faster kinetics than Pt for both methanol of ethanol oxidation, Pt can provide much higher stoichiometries for ethanol oxidation. The value of this methodology for catalyst screening is demonstrated with mixed Pt/C + PtRu/C anodes which show a pronounced synergistic effect relative to the individual Pt/C and PtRu/C catalysts. Direct alcohol fuel cells are emerging technologies for power production from renewable fuels.1-5 Direct methanol fuel cells (DMFC) with polymer electrolyte membranes (PEM) are already well developed and have achieved small scale commercialization.6-8 Direct ethanol fuel cells (DEFC) are more attractive for sustainable energy production.9,10 However, although there have been a number of demonstration projects, 6,10 performances are not yet sufficient for commercialization.10 Ethylene glycol 11,12 and glycerol 13 are also being studied for use in fuel cells, but present more complex problems.There are many challenges that are impeding the development of DAFC technology. 1,7,10,14 Relative to hydrogen PEMFCs, which already have relatively large markets, DAFCs suffer from much larger anode overpotentials, efficiency and power loses due to fuel crossover, and incomplete oxidation of the fuel. The primary requirement for commercialization of ethanol, ethylene glycol and glycerol fuel cells is the development of anode catalysts that oxidize these fuels completely to carbon dioxide at low overpotentials.12,15-17 Better anode catalysts are also required for widespread implementation of DMFC technology. 18The importance of DAFC technology for a sustainable energy future based on clean and efficient use of renewable fuels has resulted in intensive studies of the electrochemical oxidation of alcohols and the development of thousands of different anode catalysts. Generally, these have been evaluated at ambient temperatures in liquid electrolytes by cyclic voltammetry and in many cases by chronoamperometry. Products have been analyzed in some cases by techniques such as FTIR spectroscopy 16,[19][20][21] and differential electrochemica...

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confidence: 99%

Kinetics and Stoichiometry of Methanol and Ethanol Oxidation in Multi-Anode Proton Exchange Membrane Cells

Brueckner

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2017

J. Electrochem. Soc.

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“…[26,29] k f and k D are the reaction rates for formation and dissociation of the CO complex, respectively. The coupled temperature dependent rate equations corresponding to (1) and (2) [29,30] These fits are presented in Figure 1 as solid lines. The satisfactory quality of the fits suggests that assuming k f values from hard-sphere collision theory is a fairly good approximation.…”

Section: Resultsmentioning

confidence: 99%

“…For instance, in direct methanol (DMFC) and direct ethanol (DEFC) fuel cells, the alcohols are oxidized on a Pt catalyst, producing carbon dioxide, protons and electrons. [1,2] Fuel cells based on biofuels are a promising alternative for the combustion of fossil fuels as a source of energy, but the high reactivity of the platinum catalysts towards carbon monoxide is a major drawback. Carbon monoxide, which can be generated as reaction intermediate at the cell's anode, adsorbs on the surface of the Pt nanoparticles thereby reducing the number of active sites and thus the fuel cell's performance.…”

Section: Introductionmentioning

confidence: 99%

Effects of Charge Transfer on the Adsorption of CO on Small Molybdenum‐Doped Platinum Clusters

Ferrari

Vanbuel

Tam

et al. 2017

Chemistry A European J

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Abstract:The interaction of carbon monoxide with platinum alloy nanoparticles is an important problem in the context of fuel cell catalysis. In this work, molybdenum doped platinum clusters are studied in the gas phase, in order to obtain a better understanding of the fundamental nature of the Pt-CO interaction in the presence of a dopant atom. For this purpose, Ptn + and MoPtn -1 + (n=3-7) clusters are studied by combined mass spectrometry and density functional theory calculations, making it possible to investigate the effects of Mo doping on the reactivity between platinum clusters and CO. In addition, infrared photodissociation spectroscopy is used to measure the stretching frequency of CO molecules adsorbed on Ptn + and MoPtn -1 + (n=3-14), allowing an investigation of dopant induced charge redistributions within the clusters. These electronic charge transfers are correlated to the observed changes in reactivity.

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“…But to move towards real-time operations of DMFCs that meet a commercially acceptable standard, further improvements are still needed especially in the fields of systematic stability. During the past decades, lots of research efforts have been dedicated to enhance the system stability in DMFCs by improving the catalyst loading [4,5], the fuel cell structure [6,7] and the fuel delivery system [3,8], etc.…”

Section: Introductionmentioning

confidence: 99%

“…Because of the polarization effect, the over-potential phenomenon is normally inevitable. An obvious voltage deviation is often encountered, even if the DMFC was assumed to be operated in the theoretical ohmic loss range [8,9]. Many published experimental results have shown that the output voltage could be very sensitive to a small variation of current density [2,5,6,7].…”

Section: Introductionmentioning

confidence: 99%

An Adaptive Operation Strategy for Voltage Stability Enhancement in DMFCs

Yang¹,

Hu²,

Zhu³

et al. 2018

Preprint

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A review on durability issues and restoration techniques in long-term operations of direct methanol fuel cells

Cited by 127 publications

References 175 publications

Kinetics and Stoichiometry of Methanol and Ethanol Oxidation in Multi-Anode Proton Exchange Membrane Cells

Kinetics and Stoichiometry of Methanol and Ethanol Oxidation in Multi-Anode Proton Exchange Membrane Cells

Effects of Charge Transfer on the Adsorption of CO on Small Molybdenum‐Doped Platinum Clusters

An Adaptive Operation Strategy for Voltage Stability Enhancement in DMFCs

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