Non-Covalent Integration of a [FeFe]-Hydrogenase Mimic to Multiwalled Carbon Nanotubes for Electrocatalytic Hydrogen Evolution

Surface integration of molecular catalysts inspired from the active sites of hydrogenase enzymes represents a promising route towards developing noble metal-free and sustainable technologies for H-2 production. Efficient and stable catalyst anchoring is a key aspect to enable this approach. Herein, we report the preparation and electrochemical characterization of an original diironhexacarbonyl complex including two pyrene groups per catalytic unit in order to allow for its smooth integration, through pi-interactions, onto multiwalled carbon nanotube-based electrodes. In this configuration, the grafted catalyst could reach turnover numbers for H-2 production (TONH2) of up to 4 +/- 2x10(3) within 20 h of bulk electrolysis, operating at neutral pH. Post operando analysis of catalyst functionalized electrodes revealed the degradation of the catalytic unit occurred via loss of the iron carbonyl units, while the anchoring groups and most part of the ligand remained attached onto multiwalled carbon nanotubes.

Automated summary

Surface integration of molecular catalysts inspired by hydrogenase enzymes' active sites offers a promising approach for developing noble metal-free and sustainable H2 production technologies. In this study, a diironhexacarbonyl complex with two pyrene groups per catalytic unit was prepared and electrochemically characterized, allowing for its smooth integration onto multiwalled carbon nanotube-based electrodes through pi-interactions. The grafted catalyst achieved turnover numbers for H2 production of up to 4 +/- 2x10(3) within 20 hours of bulk electrolysis at neutral pH.