title: Photocatalytic H2production using a hybrid assembly of an [FeFe]-hydrogenase model and CdSe quantum dot linked through a thiolato-functionalized cyclodextrin.
abstract: It is a great challenge to develop iron-based highly-efficient and durable catalytic systems for the hydrogen evolution reaction (HER) by understanding and learning from [FeFe]-hydrogenases. Here we report photocatalytic H2production by a hybrid assembly of a sulfonate-functionalized [FeFe]-hydrogenase mimic (1) and CdSe quantum dot (QD), which is denoted as 1/β-CD-6-S-CdSe (β-CD-6-SH = 6-mercapto-β-cyclodextrin). In this assembly, thiolato-functionalized β-CD acts not only as a stabilizing reagent of CdSe QDs but also as a host compound for the diiron catalyst, so as to confine CdSe QDs to the space near the site of diiron catalyst. In addition, another two reference systems comprising MAA-CdSe QDs (HMAA = mercaptoacetic acid) and 1 in the presence and absence of β-CD, denoted as 1/β-CD/MAA-CdSe and 1/MAA-CdSe, were studied for photocatalytic H2evolution. The influences of β-CD and the stabilizing reagent β-CD-6-S-on the stability of diiron catalyst, the fluorescence lifetime of CdSe QDs, the apparent electron transfer rate, and the photocatalytic H2-evolving efficiency were explored by comparative studies of the three hybrid systems. The 1/β-CD-6-S-CdSe system displayed a faster apparent rate for electron transfer from CdSe QDs to the diiron catalyst compared to that observed for MAA-CdSe-based systems. The total TON for visible-light driven H2evolution by the 1/β-CD-6-S-CdSe QDs in water at pH 4.5 is about 2370, corresponding to a TOF of 150 h-1in the initial 10 h of illumination, which is 2.7- and 6.6-fold more than the amount of H2produced from the reference systems 1/β-CD/MAA-CdSe and 1/MAA-CdSe. Additionally, 1/β-CD-6-S-CdSe gave 2.4-5.1 fold enhancement in the apparent quantum yield and significantly improved the stability of the system for photocatalytic H2evolution.
authors.affiliation: State Key Laboratory of Fine Chemicals, DUT-KTH Joint Education and Research Center on Molecular Devices, Dalian University of Technology (DUT), Dalian 116024, China. symbueno@dlut.edu.cn.
authors.forename: Minglun
authors.initials: M
authors.lastname: Cheng
authors.forename: Mei
authors.initials: M
authors.lastname: Wang
authors.forename: Shuai
authors.initials: S
authors.lastname: Zhang
authors.forename: Fengyuan
authors.initials: F
authors.lastname: Liu
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.forename: Boshun
authors.initials: B
authors.lastname: Wan
authors.forename: Licheng
authors.initials: L
authors.lastname: Sun