A model for direct ethanol fuel cells considering variations in the concentration of the species

Souza, M.M. De; Gomes, Ranon de Souza; Bortoli, Álvaro Luiz De

doi:10.1016/j.ijhydene.2018.05.096

Cited by 12 publications

(10 citation statements)

References 39 publications

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“…Fuel flow rate and concentration are two parameters considered in the development of mathematical models in the research of De Souza et al 109 The yield of the benchmark is limiting current density and is consistent with observations in the literature. Dutta et al 110 combined three different states of element as support material in the DEFC catalyst; the fabricated catalyst has transitional metal/metal oxide/hydroxide (Ni/NiO/Ni (OH) 2 ).…”

Section: Class Of Dlfcsupporting

confidence: 82%

Progress and challenges: Review for direct liquid fuel cell

et al. 2021

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Summary Direct liquid fuel cell (DLFC) is one of the leading fuel cell types due to their great features of superior energy density, modest configuration, small size in fuel container, immediate boosting, and effortless storage and carriage. Commercially used liquid fuel types are prepared using alcohols, such as methanol or ethanol, glycol, and acids. DLFCs face great challenges although they are potentially far‐reaching depending on the expensive catalysts and the use of high‐loading catalyst. More questions that should be addressed to ensure excellent DLFC performance include cathode flooding, fuel crossover, numerous side yield production, fuel security, and unverified elongated‐duration robustness. Further studies need to be carried out to ensure the continuous improvement of the quality of DLFCs' performance and their penetration in the commercial market. To date, direct liquid fuel cells made of methanol and ethanol have been successfully produced in commercial scale, but other types of DLFCs are still under study. In this review, introduction to DLFC will be discussed by covering work and commercialization as well as recent progress and challenges encountered.

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Section: Class Of Dlfcsupporting

confidence: 82%

Progress and challenges: Review for direct liquid fuel cell

et al. 2021

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“…The onset ethanol oxidation potential (E onset-Ethanol ) is another important parameter to be evaluated. E onset-Ethanol is related to the bi-functional mechanism as well as the thermodynamics of the reactions [26,33,47]. The insertion of other metals and their oxides in Pt-based catalysts could supply oxygen species at low potentials that can help in ethanol oxidation [26,46,48].…”

Section: Electrochemical Characterizationmentioning

confidence: 99%

Catalysts of PtSn/C Modified with Ru and Ta for Electrooxidation of Ethanol

Queiroz

Ribeiro

2019

Catalysts

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PtSn/C-type catalysts modified with Ta and Ru were prepared by the thermal decomposition of polymeric precursors with the following nominal compositions: Pt70Sn10Ta20/C, Pt70Sn10Ta15Ru5/C, Pt70Sn10Ta10Ru10/C and Pt70Sn10Ta5Ru15/C. The physicochemical characterization was performed by X-ray diffraction (XRD) and energy dispersive X-ray (EDX). The electrochemical characterization was performed using cyclic voltammetry, chronoamperometry and fuel cell testing. PtSnTaRu/C catalysts were characterized in the absence and presence of ethanol in an acidic medium (H2SO4 0.5 mol L−1). All the catalysts showed activity for the oxidation of ethanol. The results indicated that the addition of Ta increased the stability and performance of the catalysts, as the Pt70Sn10Ta20/C catalyst had the maximum power density of 27.3 mW cm−2 in an acidic medium. The results showed that the PtSn/C-type catalysts modified with Ta and Ru showed good performance against alcohol oxidation, representingan alternative to the use of direct ethanol fuel cells.

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“…Surprisingly, this drastic simplification, which completely overlooks the electrochemical complexities of the EOR, is still used today [55,56]. By contrast, other models considered the oxidation of ethanol to acetic acid with the transfer of only 4 electrons [52,57,58,59,60,61,62,63,64]. It was not until recently that some DEFC models started to account for the complex multi-step kinetics of the EOR, including the effect of intermediate species such as acetic acid and acetaldehyde [54,65,66].…”

Section: Introductionmentioning

confidence: 99%

“…Due to the relevance of crossover in DEFC performance, most models also include this effect [47,48,49,50,55,56,58,62,63,64]. Since the molecular structures of ethanol and methanol are very similar, all crossover models for ethanol are based on those previously developed for methanol, where the crossover fluxes are driven mainly by diffusion and electro-osmotic drag, with hydraulic permeation only included occasionally [53].…”

Section: Introductionmentioning

confidence: 99%

“…Two-dimensional (2D) along-the-channel models are more scarce [51,61,65] and typically treat the electrochemical reactions at the catalyst layers as boundary, or jump, conditions. Fully three-dimensional (3D) studies have also been reported, but are still limited to very simple geometries [62,63,64] or to CFD analyses of realistic flow fields that ignore all electrochemical phenomena [69]. It is worth noting that all modeling studies except one [56] have considered isothermal conditions.…”

Section: Introductionmentioning

confidence: 99%

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A mathematical model for direct ethanol fuel cells based on detailed ethanol electro-oxidation kinetics

2019

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This paper presents an isothermal, single-phase model for direct ethanol fuel cells. The ethanol electrooxidation reaction is described using a detailed kinetic model that is able to predict anode polarization and product selectivity data. The anode kinetic model is coupled to a one-dimensional (1D) description for mass and charge transport across the membrane electrode assembly, which accounts for the mixed potential induced in the cathode catalyst layer by the crossover of ethanol and acetaldehyde. A simple 1D advection model is used to describe the spatial variation of the concentrations of the different species as well as the output and parasitic current densities along the flow channels. The proposed 1D+1D model includes two adjustable parameters that are fitted by a genetic algorithm in order to reproduce previous experimental data. The calibrated model is then used to investigate the consumption of ethanol and the production, accumulation and consumption of acetaldehyde along the flow channels, which yields the product selectivity at different channel cross-sections. A parametric study is also presented for varying ethanol feed concentrations and flow rates. The results obtained under ethanol starvation conditions highlight the role of acetaldehyde as main free intermediate, which is first produced and later consumed once ethanol is fully depleted. The detailed kinetic description of the ethanol oxidation reaction enables the computation of the four efficiencies (i.e., theoretical, voltage, faradaic, end energy utilization) that characterize the operation of direct ethanol fuel cells, thus allowing to present overall fuel efficiency vs. cell current density curves for the first time.

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A model for direct ethanol fuel cells considering variations in the concentration of the species

Cited by 12 publications

References 39 publications

Progress and challenges: Review for direct liquid fuel cell

Progress and challenges: Review for direct liquid fuel cell

Catalysts of PtSn/C Modified with Ru and Ta for Electrooxidation of Ethanol

A mathematical model for direct ethanol fuel cells based on detailed ethanol electro-oxidation kinetics

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