Secondary coordination sphere accelerates hole transfer for enhanced hydrogen photogeneration from [FeFe]-hydrogenase mimic and CdSe QDs in water

Abstract

Achieving highly efficient hydrogen (H2) evolution via artificial photosynthesis is a great ambition pursued by scientists in recent decades because H2 has high specific enthalpy of combustion and benign combustion product. [FeFe]-Hydrogenase ([FeFe]-H2ase) mimics have been demonstrated to be promising catalysts for H2 photoproduction. However, the efficient photocatalytic H2 generation system, consisting of PAA-g-Fe2S2, CdSe QDs and H2A, suffered from low stability, probably due to the hole accumulation induced photooxidation of CdSe QDs and the subsequent crash of [FeFe]-H2ase mimics. In this work, we take advantage of supramolecular interaction for the first time to construct the secondary coordination sphere of electron donors (HA−) to CdSe QDs. The generated secondary coordination sphere helps realize much faster hole removal with a ~30-fold increase, thus leading to higher stability and activity for H2 evolution. The unique photocatalytic H2 evolution system features a great increase of turnover number to 83600, which is the highest one obtained so far for photocatalytic H2 production by using [FeFe]-H2ase mimics as catalysts.

Nitrogenase inspired artificial photosynthetic nitrogen fixation

“…Additionally, proton transfer (k pt ) was enhanced through secondary coordination using functionalized polymeric scaffolds. 117,118 The demand of multi-electron transfer further encouraged the mimic of ''antenna effect'' in Photosystem I (PS I) by installing multiple photosensitizers around the catalyst to facilitate concurrent delivery of electrons. 8 Step by step, the progress, as shown in Figure 8, led to the growth of catalytic H 2 evolution TON from almost null to over 10 7 , which heralded the ''dawn'' of enlightenment in photocatalytic H 2 evolution.…”

Hydroxyl-Decorated Diiron Complex as a [FeFe]-Hydrogenase Active Site Model Complex: Light-Driven Photocatalytic Activity and Heterogenization on Ethylene-Bridged Periodic Mesoporous Organosilica

“…Accordingly, the scientific community has made enormous efforts to the preparation of functional biomimetic systems based on [FeFe]-hydrogenase by modifying the first, second, or even outer coordination sphere [28,[31][32][33][34], thus being capable of acting as artificial proton reduction catalysts in hydrogen evolution reactions. In fact, we have recently reported a comprehensive review of [FeFe]-hydrogenase-inspired catalysts applied in photocatalytic hydrogen production, including molecular [2Fe2S] catalysts, photosensitizer-[FeFe]-hydrogenase dyads, electron donor-photosensitizer-[FeFe]-hydrogenase triads, supramolecular entities, hybrid semiconductor assemblies, heterogeneous supports and photocathodes based on [2Fe2S] for photoelectrochemical (PEC) devices.…”

Influence of Surface Ligands on Charge-Carrier Trapping and Relaxation in Water-Soluble CdSe@CdS Nanorods

“…Thus, systems with this type of ligand are suitable only for photocatalytic systems working at pH > 6 as has been shown for CdSe@CdS nanorods decorated with platinum or nickel particles [12,[19][20][21][22]. However, some catalysts for the hydrogen evolution reaction such as [FeFe]-hydrogenase-mimics [23][24][25] or certain metal dichalcogenide nanoparticles, e.g., MoS 2 , [26,27] require acidic conditions for best performance. Accordingly, for use under these conditions, the hydrophilic segment has to be replaced from a carboxyl group to a moiety allowing for dispersibility at acidic pH or, to realize systems with highest flexibility, dispersibility over a wide pH range.…”