The hydrogen dependent CO2 reductase: the first completely CO tolerant FeFe-hydrogenase

Abstract

The Hydrogen Dependent Carbon dioxide Reductase (HDCR) from Acetobacterium woodii presents a promising solution to the issue of H₂ storage by reversibly coupling H₂ oxidation to CO₂ reduction. We here report on the electrocatalytic properties of the hydrogenase (Hase) module in the intact complex, including (an)aerobic oxidation, CO inhibition and the first systematic analysis of the catalytic bias (CB) of a Hase. CB depends on pH, regardless of the H₂ concentration, despite a higher affinity for H₂ than other FeFe-Hases. Remarkably, CO inhibition is fully reversible under all oxidation states of the active site, making HDCR the first “syngas-friendly” FeFe-Hase.