A Redox Hydrogel Protects the O2‐Sensitive [FeFe]‐Hydrogenase from Chlamydomonas reinhardtii from Oxidative Damage

Abstract The integration of sensitive catalysts in redox matrices opens up the possibility for their protection from deactivating molecules such as O 2 . [FeFe]‐hydrogenases are enzymes catalyzing H 2 oxidation/production which are irreversibly deactivated by O 2 . Therefore, their use under aerobic conditions has never been achieved. Integration of such hydrogenases in viologen‐modified hydrogel films allows the enzyme to maintain catalytic current for H 2 oxidation in the presence of O 2 , demonstrating a protection mechanism independent of reactivation processes. Within the hydrogel, electrons from the hydrogenase‐catalyzed H 2 oxidation are shuttled to the hydrogel–solution interface for O 2 reduction. Hence, the harmful O 2 molecules do not reach the hydrogenase. We illustrate the potential applications of this protection concept with a biofuel cell under H 2 /O 2 mixed feed.