A bio-inspired mononuclear manganese catalyst for high-rate electrochemical hydrogen production

Abstract

[FeFe]-hydrogenase (H₂ase) catalyzes hydrogen evolution reactions (HERs), with an excellent performance that rivals that of platinum, the active site of which is built with crucial structural features required for efficient H–H bond formation. Herein, we report a mononuclear manganese complex (1) that contains a square pyramid coordination sphere and an intramolecular aniline as the proton relay, consistent with the crucial features of the active site in H₂ase. Benefitting from these features, complex 1 electrocatalyzes the HER with a turnover frequency (TOF) exceeding 10 000 s⁻¹ at −1.45 V (versus the ferrocenium/ferrocene couple) using anilinium tetrafluoroborate as a proton source. This work provides the first Mn-based functional model of H₂ase, serving as a new paradigm for a high performance, low cost, environmentally benign hydrogen production electrocatalyst.