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Enhanced Electrosynthetic Hydrogen Evolution by Hydrogenases Embedded in a Redox‐Active Hydrogel
Author(s) -
Ruth John C.,
Milton Ross D.,
Gu Wenyu,
Spormann Alfred M.
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202000750
Subject(s) - hydrogenase , overpotential , redox , chemistry , hydrogen , formate dehydrogenase , electron transfer , faraday efficiency , electrochemistry , combinatorial chemistry , formate , chemical engineering , photochemistry , materials science , inorganic chemistry , catalysis , electrode , biochemistry , organic chemistry , engineering
Molecular hydrogen is a major high‐energy carrier for future energy technologies, if produced from renewable electrical energy. Hydrogenase enzymes offer a pathway for bioelectrochemically producing hydrogen that is advantageous over traditional platforms for hydrogen production because of low overpotentials and ambient operating temperature and pressure. However, electron delivery from the electrode surface to the enzyme's active site is often rate‐limiting. Here, it is shown that three different hydrogenases from Clostridium pasteurianum and Methanococcus maripaludis , when immobilized at a cathode in a cobaltocene‐functionalized polyallylamine (Cc‐PAA) redox polymer, mediate rapid and efficient hydrogen evolution. Furthermore, it is shown that Cc‐PAA‐mediated hydrogenases can operate at high faradaic efficiency (80–100 %) and low apparent overpotential (−0.578 to −0.593 V vs. SHE). Specific activities of these hydrogenases in the electrosynthetic Cc‐PAA assay were comparable to their respective activities in traditional methyl viologen assays, indicating that Cc‐PAA mediates electron transfer at high rates, to most of the embedded enzymes.