An electrochemical cell with Gortex-based electrodes capable of extracting pure hydrogen from highly dilute hydrogen–methane mixtures

Wagner, Klaudia; Tiwari, Prerna; Swiegers, Gerhard F.; Wallace, Gordon G.

doi:10.1039/c7ee02236k

Cited by 15 publications

(11 citation statements)

References 26 publications

(19 reference statements)

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“…Clearly, there was no significant hindrance to gas transport into or out of the Gortex GDEs. This confirmed previous findings in this respect. , …”

Section: Results and Discussionsupporting

confidence: 93%

“…Other than the present series of studies [14][15] and several recent reports in which Gortex membranes were coated with weakly-catalytic conducting polymers and sputtered metals or used in microbial fuel cells, [16][17][18][19][20] Gortex does not appear to have been formally considered as an electrode substrate in its own right. Moreover, no attempt has been made to select (based on a commercially-available engineering specification) or study the physical properties of a coated Gortex-based gas diffusion electrode.…”

Section: 3mentioning

confidence: 95%

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Gortex-Based Gas Diffusion Electrodes with Unprecedented Resistance to Flooding and Leaking

Tiwari

Tsekouras

Swiegers

et al. 2018

ACS Appl. Mater. Interfaces

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A significant and long-standing problem in electrochemistry has demanded the need for gas diffusion electrodes that are "flood-proof" and "leak-proof" when operated with a liquid electrolyte. The absence of a solution to this problem has, effectively, made it unviable to use gas diffusion electrodes in many electrochemical manufacturing processes, especially as " gas-depolarized" counter electrodes with significantly decreased energy consumption. In this work, Gortex membranes (also known as expanded PTFE or ePTFE) have been studied as novel, leak-proof substrates for gas diffusion electrodes [PTFE = poly(tetrafluoroethylene)]. We report the fabrication, characterization, and operation of gas diffusion electrodes comprising finely pored Gortex overcoated with 10% Pt on Vulcan XC72, PTFE binder, and a fine Ni mesh as a current carrier. Capillary flow porometry indicated that the electrodes only flooded/leaked when the excess of pressure on their liquid-side over their gas-side was 5.7 atm. This is more than an order of magnitude greater than any previous gas diffusion electrode. The Gortex electrodes were tested as hydrogen- and oxygen-depolarized anodes and cathodes in an alkaline fuel cell in which the liquid electrolyte was pressurized to 0.5-1.5 atm above the gas pressures. Despite the record high electrolyte pressure, the electrodes, which had Pt loadings of only 0.075 mg Pt/cm, exhibited notable activity over 2 d of continuous, leak-free operation. Under the applied liquid pressure, the fuel cell also overcame all of the key technical challenges that have hindered the adoption of alkaline fuel cells to date. The high activity and unprecedented resistance to leaking/flooding exhibited by these electrodes, even when subjected to large liquid electrolyte overpressures under gas depolarization conditions, provide an important advance with far-reaching implications for electrochemical manufacturing.

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“…Clearly, there was no significant hindrance to gas transport into or out of the Gortex GDEs. This confirmed previous findings in this respect. , …”

Section: Results and Discussionsupporting

confidence: 93%

Section: 3mentioning

confidence: 95%

Gortex-Based Gas Diffusion Electrodes with Unprecedented Resistance to Flooding and Leaking

Tiwari

Tsekouras

Swiegers

et al. 2018

ACS Appl. Mater. Interfaces

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“…The H 2 flux at 0.51 V was J H2 = 2.4 mL cm −2 min −1 with a H 2 yield of η H2 = 25% and a Faraday's efficiency of 96%, higher than achieved for an electrochemical cell with Gortex-based electrodes. 26 Increasing the pumping voltage above 0.51 V produced a slight enhancement in the H 2 yield, e.g., 29% at 0.73 V but resulted in a pronounced drop in the Faraday's efficiency, e.g., 84% at 0.73 V.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Protonic Ceramic Electrochemical Cell for Efficient Separation of Hydrogen

Tong

Meng

Luo

et al. 2020

ACS Appl. Mater. Interfaces

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Advancement of a hydrogen economy requires establishment of a whole supply chain including hydrogen production, purification, storage, utilization, and recovery. Nevertheless, it remains challenging to selectively purify hydrogen out of H 2 -containing streams, especially at low concentrations. Herein, a novel protonic ceramic electrochemical cell is reported that can sustainably separate pure H 2 out of H 2 -diluted streams over the temperature regime of 350−500 °C by mildly controlling the electric voltage. With the Faraday's efficiency above 96%, the measured H 2 separation rate at 0.51 V and 500 °C is 3.3 mL cm −2 min −1 out of 10% H 2 -90% N 2 , or 2.4 mL cm −2 min −1 out of 10% H 2 -90% CH 4 taken as an example of renewable hydrogen blended in the natural gas pipelines. Such high hydrogen separation capability at reduced temperatures is enabled by the nanoporous nickel catalysts and well-bonded electrochemical interfaces as produced from well-controlled in situ slow reduction of nickel oxides. These results demonstrate technical feasibility of onsite purification of hydrogen prior to their practical applications such as fuels for fuel cell electric vehicles.

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“…The best-known techniques for separation of hydrogen from a gas mixture are: adsorption techniques (e.g., pressure swing adsorption-PSA); [2,3] low temperature process (temperatures <À180 C); [4] membrane techniques (diffusion separation, electrochemical separation processes); [5][6][7][8][9] combination of both membrane and PSA; [10] selective absorption (metal hydrides storage). Unfortunately, PSA methods are generally used at relatively high hydrogen concentrations (58% [11] or between 75% and 90% [12] ), whereas the low-temperature processes are considered costly while the purity grades of H 2 does not exceed 98%.…”

Section: Introductionmentioning

confidence: 99%

“…Moreover, metal hydrides can be used for separation of H 2 from natural gas at low H 2 concentrations (<10 vol%), which is impossible with most of conventional separation processes. [5] Various lowtemperature metal hydrides have already been studied according to their H 2 separation potential (LaNi 5 -, FeTi-, Fe-Ti-Ni-, Ti-Mn-type alloys). [14][15][16][17][18] The separation of hydrogen from gas mixtures using hydrides has already been demonstrated in application.…”

Section: Introductionmentioning

confidence: 99%

Mg‐Based System for H₂ Sorption from CH₄/H₂ Gas Mixture

et al. 2021

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Magnesium is considered as a potential material for the separation of hydrogen from different gas streams (CH4/H2, syngas, natural gas, etc.). Herein, an elemental mixture of Mg and Ni (5 wt%) is used for selective absorption of hydrogen from a CH4/H2 (90:10) mixture at 350 °C. The performed studies (X‐ray diffraction, thermogravimetric analysis, differential scanning calorimetry, and gas chromatography) show that analyzed material absorbs 4.5 wt% of hydrogen from CH4/H2 gas mixture and can be successfully applied for H2 separation. The proposed material may also be a promising system to capture hydrogen transported through natural gas networks.

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An electrochemical cell with Gortex-based electrodes capable of extracting pure hydrogen from highly dilute hydrogen–methane mixtures

Abstract: In this work we report a novel liquid–acid electrochemical cell containing Gortex-based gas diffusion electrodes, layered with suitable catalysts and current collectors, that is capable of sustainably extracting pure hydrogen from methane mixtures containing as little as 5% hydrogen.

Cited by 15 publications

References 26 publications

Gortex-Based Gas Diffusion Electrodes with Unprecedented Resistance to Flooding and Leaking

Gortex-Based Gas Diffusion Electrodes with Unprecedented Resistance to Flooding and Leaking

Protonic Ceramic Electrochemical Cell for Efficient Separation of Hydrogen

Mg‐Based System for H₂ Sorption from CH₄/H₂ Gas Mixture

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An electrochemical cell with Gortex-based electrodes capable of extracting pure hydrogen from highly dilute hydrogen–methane mixtures

Abstract: In this work we report a novel liquid–acid electrochemical cell containing Gortex-based gas diffusion electrodes, layered with suitable catalysts and current collectors, that is capable of sustainably extracting pure hydrogen from methane mixtures containing as little as 5% hydrogen.

Cited by 15 publications

References 26 publications

Gortex-Based Gas Diffusion Electrodes with Unprecedented Resistance to Flooding and Leaking

Gortex-Based Gas Diffusion Electrodes with Unprecedented Resistance to Flooding and Leaking

Protonic Ceramic Electrochemical Cell for Efficient Separation of Hydrogen

Mg‐Based System for H2 Sorption from CH4/H2 Gas Mixture

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Product

Resources

About

Mg‐Based System for H₂ Sorption from CH₄/H₂ Gas Mixture