Open AccessReversible H2 oxidation and evolution by hydrogenase embedded in a redox polymer film
Author(s) -
Steffen Hardt,
Stefanie Stapf,
Dawit T. Filmon,
James A. Birrell,
Olaf Rüdiger,
Vincent Fourmond,
Christophe Léger,
Nicolas Plumeré
Publication year - 2021
Publication title -
nature catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 14.33
H-Index - 65
ISSN - 2520-1158
DOI - 10.1038/s41929-021-00586-1
Subject(s) - hydrogenase , redox , overpotential , catalysis , electron transfer , anode , electrocatalyst , materials science , nanotechnology , water splitting , cathode , combinatorial chemistry , chemistry , chemical engineering , photochemistry , electrochemistry , electrode , inorganic chemistry , organic chemistry , photocatalysis , engineering
Efficient electrocatalytic energy conversion requires the devices to function reversibly, i.e. deliver a significant current at minimal overpotential. Redox-active films can effectively embed and stabilise molecular electrocatalysts, but mediated electron transfer through the film typically makes the catalytic response irreversible. Here, we describe a redox-active film for bidirectional (oxidation or reduction) and reversible hydrogen conversion, consisting of [FeFe] hydrogenase embedded in a low-potential, 2,2'-viologen modified hydrogel. When this catalytic film served as the anode material in a H 2 /O 2 biofuel cell, an open circuit voltage of 1.16 V was obtained - a benchmark value near the thermodynamic limit. The same film also acted as a highly energy efficient cathode material for H 2 evolution. We explained the catalytic properties using a kinetic model, which shows that reversibility can be achieved despite intermolecular electron transfer being slower than catalysis. This understanding of reversibility simplifies the design principles of highly efficient and stable bioelectrocatalytic films, advancing their implementation in energy conversion.