Hydrophobicity Graded Gas Diffusion Layer for Stable Electrochemical Reduction of CO2

To mitigate flooding associated with the gas diffusion layer (GDL) during electroreduction of CO2, we report a hydrophobicity‐graded hydrophobic GDL (HGGDL). Coating uniformly dispersed polytetrafluoroethylene (PTFE) binders on the carbon fiber skeleton of a hydrophilic GDL uniformizes the hydrophob...

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Bibliographic Details
Published in:Angewandte Chemie 2022-09, Vol.134 (39), p.n/a
Main Authors: Li, Linbo, Chen, Jun, Mosali, Venkata Sai Sriram, Liang, Yan, Bond, Alan M., Gu, Qinfen, Zhang, Jie
Format: Article
Language:English
Subjects:
Binders
Carbon dioxide
Carbon fibers
Carbon Gas Diffusion Layer
Catalysts
Chemical reduction
Chemistry
Diffusion layers
Electrochemical CO2 Reduction
Electrochemistry
Electrodes
Flooding
Gas transport
Gaseous diffusion
Hydrophobicity
Hydrophobicity and Pore Size Control
Hydrophobicity Graded
Nickel
Polytetrafluoroethylene
Pore size
Sintering (powder metallurgy)
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Summary:To mitigate flooding associated with the gas diffusion layer (GDL) during electroreduction of CO2, we report a hydrophobicity‐graded hydrophobic GDL (HGGDL). Coating uniformly dispersed polytetrafluoroethylene (PTFE) binders on the carbon fiber skeleton of a hydrophilic GDL uniformizes the hydrophobicity of the GDL and also alleviates the gas blockage of pore channels. Further adherence of the PTFE macroporous layer (PMPL) to one side of the hydrophobic carbon fiber skeleton was aided by sintering. The introduced PMPL shows an appropriate pore size and enhanced hydrophobicity. As a result, the HGGDL offers spatial control of the hydrophobicity and hence water and gas transport over the GDL. Using a nickel‐single‐atom catalyst, the resulting HGGDL electrode provided a CO faradaic efficiency of over 83 % at a constant current density of 75 mA cm−2 for 103 h operation in a membrane electrode assembly, which is more than 16 times that achieved with a commercial GDL. A new hydrophobicity engineering method has been developed to transform a hydrophilic carbon gas diffusion layer into a hydrophobicity‐graded one. This modification controls gas transport and hydrophobicity as well as mitigates electrolyte flooding of the gas diffusion layer, hence, facilitating stable electrochemical CO2 reduction.
ISSN:0044-8249
1521-3757
DOI:10.1002/ange.202208534