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Direct Electrolytic Splitting of Seawater: Activity, Selectivity, Degradation, and Recovery Studied from the Molecular Catalyst Structure to the Electrolyzer Cell Level
Author(s) -
Dresp Sören,
Dionigi Fabio,
Loos Stefan,
Ferreira de Araujo Jorge,
Spöri Camillo,
Gliech Manuel,
Dau Holger,
Strasser Peter
Publication year - 2018
Publication title -
advanced energy materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 10.08
H-Index - 220
eISSN - 1614-6840
pISSN - 1614-6832
DOI - 10.1002/aenm.201800338
Subject(s) - materials science , seawater , electrolysis , anode , catalysis , electrolyte , chemical engineering , cathode , electrolysis of water , electrolytic cell , electrode , chemistry , oceanography , engineering , geology , biochemistry
Seawater electrolysis faces fundamental chemical challenges, such as the suppression of highly detrimental halogen chemistries, which has to be ensured by selective catalyst and suitable operating conditions. In the present study, nanostructured NiFe‐layered double hydroxide and Pt nanoparticles are selected as catalysts for the anode and cathode, respectively. The seawater electrolyzer is tested successfully for 100 h at maximum current densities of 200 mA cm −2 at 1.6 V employing surrogate sea water and compared to fresh water feeds. Different membrane studies are carried out to reveal the cause of the current density drop. During long‐term dynamic tests, under simulated day‐night cycles, an unusual cell power performance recovery effect is uncovered, which is subsequently harnessed in a long‐term diurnal day‐night cycle test. The natural day‐night cycles of the electrolyzer input power can be conceived as a reversible catalyst materials recovery treatment of the device when using photovoltaic electricity sources. To understand the origin of this reversible recovery on a molecular materials level, in situ extended X‐ray absorption fine structure and X‐ray near‐edge region spectra are applied.