Highly Efficient Platinum Group Metal Free Based Membrane‐Electrode Assembly for Anion Exchange Membrane Water Electrolysis

Pavel, Claudiu C.; Cecconi, Franco; Emiliani, Chiara; Santiccioli, Serena; Scaffidi, Adriana; Catanorchi, Stefano; Comotti, Massimiliano

doi:10.1002/ange.201308099

Cited by 38 publications

(30 citation statements)

References 24 publications

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“…7,8 The thickness of the separator, its ionic conductivity and its gas permeability constitute a decisive property for the efficiency of water electrolysis, as these properties determine the ohmic drop and cross-permeation of the produced gases.…”

Section: 3mentioning

confidence: 99%

“…[4][5][6] However, these membranes typically show low durability. 7,8 The thickness of the separator, its ionic conductivity and its gas permeability constitute a decisive property for the efficiency of water electrolysis, as these properties determine the ohmic drop and cross-permeation of the produced gases. [9][10][11] A recent comparison of acidic and alkaline water electrolysis showed, that the lower hydrogen and oxygen diffusivities in alkaline electrolytes than in acidic electrolytes may be a decisive advantage of alkaline electrolyzers.…”

mentioning

confidence: 99%

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Hydrogen Diffusivity and Electrolyte Permeability of the Zirfon PERL Separator for Alkaline Water Electrolysis

Schalenbach

Lueke

Stolten

2016

J. Electrochem. Soc.

130

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The hydrogen and oxygen evolved during alkaline water electrolysis with liquid KOH electrolytes are typically separated using porous separators such as Zirfon PERL (Agfa), a commercially available composite of zirconium oxide and polysulfone. In this study, the hydrogen diffusivity (driven by concentration differences) and electrolyte permeability (driven by differential pressures) of the Zirfon PERL separator were characterized as a function of the temperature and molarity of the KOH filling. The diffusivity of hydrogen in the separator was found to be approximately 16% of that of the electrolyte filling inside its pores. With respect to water electrolysis conditions, the extent of hydrogen cross-permeation caused by the convection of the cross-permeating electrolyte was estimated and compared to that caused by diffusion. On the basis of the physically characterized mechanisms, smaller pores were predicted to reduce the differential pressure driven gas cross-permeation. In a water electrolyzer, hydrogen is evolved at the cathode (the negative pole) while oxygen is evolved at the anode (the positive pole). When both electrodes are connected by an alkaline electrolyte, hydroxide ions must permeate from the cathode to the anode in order to bring about the electrochemical reactions at the electrodes. In such alkaline water electrolyzers, typically aqueous KOH electrolytes (which provide higher conductivity than other lyes 1 ) and porous separators between both electrodes are used to provide the ionic conductivity between the electrodes and to separate the evolved gases. 2,3Alternatively, alkaline polymer electrolyte membranes can be used as the electrolyte.4-6 However, these membranes typically show low durability. 7,8 The thickness of the separator, its ionic conductivity and its gas permeability constitute a decisive property for the efficiency of water electrolysis, as these properties determine the ohmic drop and cross-permeation of the produced gases.9-11 A recent comparison of acidic and alkaline water electrolysis showed, that the lower hydrogen and oxygen diffusivities in alkaline electrolytes than in acidic electrolytes may be a decisive advantage of alkaline electrolyzers. 9Higher pressures at the gas outlets during water electrolysis means reducing the mass fraction of water in the produced gases and thus lower thermoneutral voltages. 9,12 In addition, applied pressures during water electrolysis enable efficient isothermal compression. 13 However, higher pressures increase the amount of hydrogen and oxygen diffusing through the separator, 9,10 so that porous separators that enable low gas crossover are required for efficient alkaline water electrolyzers.Composite materials of Zirconium oxide (zirconia) and polysulfone are high-performing and stable separators for alkaline water electrolysis.14,15 This type of separator combines the flexibility of the polymer with the stiffness and wettability of the ceramic zirconia. 16Agfa provides a commercially available product of this type of separator, denoted as '...

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Section: 3mentioning

confidence: 99%

mentioning

confidence: 99%

Hydrogen Diffusivity and Electrolyte Permeability of the Zirfon PERL Separator for Alkaline Water Electrolysis

Schalenbach

Lueke

Stolten

2016

J. Electrochem. Soc.

130

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“…[27] A similar approach as the one just described would consist of using AEM electrolysis cell configuration with the circulation of a carbonate/bicarbonate solution in the cathode compartment. This approach has been demonstrated to be effective for water electrolysis [51] and could be test-proofed for CO 2 electrolysis. Both of these cell configurations are depicted in Fig.…”

Section: Co 2 Electrolysis At Low Ph Conditionsmentioning

confidence: 99%

Electrochemical CO₂ Reduction – A Critical View on Fundamentals, Materials and Applications

Durst

Rudnev

Dutta

et al. 2015

Chimia

146

137

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The electrochemical reduction of CO 2 has been extensively studied over the past decades. Nevertheless, this topic has been tackled so far only by using a very fundamental approach and mostly by trying to improve kinetics and selectivities toward specific products in half-cell configurations and liquid-based electrolytes. The main drawback of this approach is that, due to the low solubility of CO 2 in water, the maximum CO 2 reduction current which could be drawn falls in the range of 0.01-0.02 A cm -2 . This is at least an order of magnitude lower current density than the requirement to make CO 2 -electrolysis a technically and economically feasible option for transformation of CO 2 into chemical feedstock or fuel thereby closing the CO 2 cycle. This work attempts to give a short overview on the status of electrochemical CO 2 reduction with respect to challenges at the electrolysis cell as well as at the catalyst level. We will critically discuss possible pathways to increase both operating current density and conversion efficiency in order to close the gap with established energy conversion technologies.

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“…7 It is well-known that platinum and its alloys are the benchmark electrocatalysts for HER because of the low overpotential and fast kinetics required for driving the reaction. [8][9][10] Unfortunately, the limited supply and expensiveness of these metals make them unattractive. As a result, enormous efforts have been devoted to finding alternative catalysts for producing hydrogen at low overpotential.…”

Section: Introductionmentioning

confidence: 99%

Nanoporous Gold Surface: An Efficient Platform for Hydrogen Evolution Reaction at Very Low Overpotential

Sukeri

Bertotti

2017

J. Braz. Chem. Soc.

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Highly Efficient Platinum Group Metal Free Based Membrane‐Electrode Assembly for Anion Exchange Membrane Water Electrolysis

Cited by 38 publications

References 24 publications

Hydrogen Diffusivity and Electrolyte Permeability of the Zirfon PERL Separator for Alkaline Water Electrolysis

Hydrogen Diffusivity and Electrolyte Permeability of the Zirfon PERL Separator for Alkaline Water Electrolysis

Electrochemical CO₂ Reduction – A Critical View on Fundamentals, Materials and Applications

Nanoporous Gold Surface: An Efficient Platform for Hydrogen Evolution Reaction at Very Low Overpotential

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