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Direct Water Injection in Catholyte‐Free Zero‐Gap Carbon Dioxide Electrolyzers
Author(s) -
De Mot Bert,
Ramdin Mahinder,
Hereijgers Jonas,
Vlugt Thijs J. H.,
Breugelmans Tom
Publication year - 2020
Publication title -
chemelectrochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.182
H-Index - 59
ISSN - 2196-0216
DOI - 10.1002/celc.202000961
Subject(s) - electrolysis , formate , faraday efficiency , precipitation , chemical engineering , electrolysis of water , sparging , chemistry , diffusion , cathode , electrode , materials science , analytical chemistry (journal) , inorganic chemistry , electrolyte , chromatography , catalysis , thermodynamics , biochemistry , physics , meteorology , engineering
A zero‐gap flow electrolyzer with a tin‐coated gas diffusion electrode as the cathode was used to convert humidified gaseous CO 2 to formate. The influence of humidification, flow pattern and the type of membrane on the faradaic efficiency (FE), product concentration, and salt precipitation were investigated. We demonstrated that water management in the gas diffusion electrode was crucial to avoid flooding and (bi)carbonate precipitation, to uphold a high FE and formate concentration. Direct water injection was validated as a novel approach for water management. At 100 mA/cm 2 , direct water injection in combination with an interdigitated flow channel resulted in a FE of 80 % and a formate concentration of 65.4+/−0.3 g/l without salt precipitation for a prolonged CO 2 electrolysis of 1 h. The use of bipolar membranes in the zero‐gap configuration mainly produced hydrogen. These results are important for the design of commercial scale CO 2 electrolyzers.