Hydrogen production at high Faradaic efficiency by a bio-electrode based on TiO2 adsorption of a new [FeFe]-hydrogenase from Clostridium perfringens

• A TiO2–[FeFe] hydrogenase bio-electrode is produced by simple adsorption.
• The enzyme retains structure/function and the bio-electrode is stable for several days.
• Hydrogen evolution occurs at 98% Faradaic efficiency at − 741 mV vs SHE.
• High turnover frequencies (≥ 4 s− 1) compare well with more expensive hybrid systems.

The [FeFe]-hydrogenase CpHydA from Clostridium perfringens was immobilized by adsorption on anatase TiO2 electrodes for clean hydrogen production. The immobilized enzyme proved to perform direct electron transfer to and from the electrode surface and catalyses both H2 oxidation (H2 uptake) and H2 production (H2 evolution) with a current density for H2 evolution of about 2 mA cm− 1. The TiO2/CpHydA bioelectrode remained active for several days upon storage and when a reducing potential was set, H2 evolution occurred with a mean Faradaic efficiency of 98%. The high turnover frequency of H2 production and the tight coupling of electron transfer, resulting in a Faradaic efficiency close to 100%, support the exploitation of the novel TiO2/CpHydA stationary electrode as a powerful device for H2 production.

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