An original 1-acetato-4-(1-pyrenyl)-1,4,7-triazacyclononane (AcPyTACN) was synthesized for the immobilization of a His-tagged recombinant CODH from Rhodospirillum rubrum (RrCODH) on carbonnanotube electrodes. The strong binding of the enzyme at the Ni-AcPyTACN complex affords a high current density of 4.9 mA cm À 2 towards electroenzymatic CO 2 reduction and a high stability of more than 6 × 10 6 TON when integrated on a gas-diffusion bioelectrode.