[NiFe]Hydrogenase from Citrobacter sp. S-77 Surpasses Platinum as an Electrode for H2 Oxidation Reaction

Reported herein is an electrode for dihydrogen (H2) oxidation, and it is based on [NiFe]Hydrogenase from Citrobacter sp. S‐77 ([NiFe]S77). It has a 637 times higher mass activity than Pt (calculated based on 1 mg of [NiFe]S77 or Pt) at 50 mV in a hydrogen half‐cell. The [NiFe]S77 electrode is also stable in air and, unlike Pt, can be recovered 100 % after poisoning by carbon monoxide. Following characterization of the [NiFe]S77 electrode, a fuel cell comprising a [NiFe]S77 anode and Pt cathode was constructed and shown to have a a higher power density than that achievable by Pt. Outperforming Pt: An electrode for the H2 oxidation reaction is based on [NiFe]Hydrogenase from Citrobacter sp. S‐77 ([NiFe]S77). It has a 637 times higher mass activity than Pt at 50 mV in a hydrogen half‐cell, is stable in air and, unlike Pt, can be recovered 100 % after poisoning by CO. A fuel cell comprising a [NiFe]S77 anode and Pt cathode was constructed and thus demonstrated a higher power density than that of Pt.