Enhanced Photochemical Hydrogen Production by a Molecular Diiron Catalyst Incorporated into a Metal-Organic Framework

Journal Article · Wed Dec 04 04:00:00 EST 2013 · Journal of the American Chemical Society

DOI:https://doi.org/10.1021/ja407176p· OSTI ID:1107412

Pullen, Sonja; Fei, Honghan; Orthaber, Andreas; Cohen, Seth M.; Ott, Sascha ^[1]

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1. Uppsala

A molecular proton reduction catalyst [FeFe](dcbdt)(CO)₆ (1, dcbdt = 1,4-dicarboxylbenzene-2,3-dithiolate) with structural similarities to [FeFe]-hydrogenase active sites has been incorporated into a highly robust Zr(IV)-based metal–organic framework (MOF) by postsynthetic exchange (PSE). The PSE protocol is crucial as direct solvothermal synthesis fails to produce the functionalized MOF. The molecular integrity of the organometallic site within the MOF is demonstrated by a variety of techniques, including X-ray absorption spectroscopy. In conjunction with [Ru(bpy)₃]²⁺ as a photosensitizer and ascorbate as an electron donor, MOF-[FeFe](dcbdt)(CO)₆ catalyzes photochemical hydrogen evolution in water at pH 5. The immobilized catalyst shows substantially improved initial rates and overall hydrogen production when compared to a reference system of complex 1 in solution. Improved catalytic performance is ascribed to structural stabilization of the complex when incorporated in the MOF as well as the protection of reduced catalysts 1^– and 1^2– from undesirable charge recombination with oxidized ascorbate.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: FOREIGN
• OSTI ID: 1107412
• Journal Information: Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: (45) ; 11, 2013 Vol. 135; ISSN 0002-7863
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: ENGLISH