Electrocatalytic O₂ Reduction by [Fe-Fe]-Hydrogenase Active Site Models

Abstract

The instability of [Fe-Fe]-hydrogenase and its synthetic models under aerobic conditions is an inherent challenge in their development as practical H2 producing electrodes. The electrochemical oxygen reduction reaction of a series of synthetic model complexes of the [Fe-Fe] hydrogenase is investigated, and a dominant role of the bridgehead nitrogen in reducing the amount of partially reduced oxygen species (PROS), which is detrimental to the stability of these complexes, is discovered.

Reactivity and Mechanism Studies of Hydrogen Evolution Catalyzed by Copper Corroles

“…17,26,[73][74][75] Therefore, the stability of 1 in concentrated TFA acetonitrile solution was evaluated ( Figure S13). Our results showed that 1 remained unaffected even in a 1:1…”

“…22,23 However, the challenge in obtaining and using these enzymes in nonnatural environments obstructs their practical applications, 24 even though the use of hydrogenases with chemical modifications under ambient environments is known in the literature. 25,26 Platinum is very active in electrocatalytic H 2 production, 8 but utilization of this noble metal is limited by its low natural abundance and high cost. Less expensive earth-abundant transition metal complexes have therefore attracted major attention to serve as catalysts for hydrogen evolution reaction (HER).…”

Mechanism of O2 diffusion and reduction in FeFe hydrogenases

“…We have shown that the reactivation results from the combined effects of the release of O 2 and its four-electron four-proton reduction to water (Figure 6), consistent with recent evidence for O 2 reduction by synthetic analogues of the H-cluster. 37 …”

Amphiphilic polymeric micelles as microreactors: improving the photocatalytic hydrogen production of the [FeFe]-hydrogenase mimic in water

“…For a photocatalytic system, the interaction between photosensitizer and catalyst, and the proton migration from bulk solution to the reduced catalyst, are two important steps for overall catalytic performance. 15 However, the photogenerated Ru(bpy) 3 + (À1.30 V) produced from the reductive quenching of excited Ru(bpy) 3 2+ by ascorbate (HA À ) Therefore, a molecular photosensitizer that is able to shuttle freely between bulk aqueous solution and hydrophobic core of micelle should be considered.…”