Metal–Organic Frameworks Integrate Cu Photosensitizers and Secondary Building Unit-Supported Fe Catalysts for Photocatalytic Hydrogen Evolution

Abstract

We report here the synthesis of a series of metal−organic frameworks (MOFs), FeX@Zr 6 -Cu, comprising cuprous photosensitizing linkers (Cu-PSs) and catalytically active Fe II centers supported on secondary building units (SBUs) for photocatalytic H 2 evolution. Close proximity (∼1 nm) between Cu-PS and SBU-supported Fe sites and stabilization of Fe sites by periodically ordered SBUs led to exceptionally high H 2 evolution activity for FeX@Zr 6 -Cu, with turnover numbers of up to 33 700 and turnover frequencies of up to 880 h −1 . Photocatalytic H 2 evolution activities of FeX@Zr 6 -Cu correlate with the lability of X counteranions, suggesting that open coordination environments of Fe sites generated by labile X groups facilitate the formation of Fe-hydride intermediates before hydrogen evolution. This work highlights the potential of using MOFs to integrate Earth-abundant components for solar energy utilization.

Photophysical Properties and Redox Potentials of Photosensitizers for Organic Photoredox Transformations

“…12,13 PSs are also referred to as photocatalysts when used in catalytic applications. The continued interest in new reactivity and improved catalytic performance has led to the emergence of a number of different types of PSs, including organic dyes, [14][15][16] inorganic semiconductors, [17][18][19] transition-metal complexes, 7,20 and metal-organic frameworks, [21][22][23] among others. Molecular PSs are particularly dominant in the field of photocatalysis on account of the maturity of the study of their photochemistry, the controllability of their structural design, and the potential to perform judicious manipulations of their electronic structure and redox properties.…”

Metal–Organic Frameworks as Versatile Platforms for Organometallic Chemistry

“…Metalation of other zirconium cluster nodes with cobalt through µ 2 and µ 3 oxide binding was also studied. In all cases, the zirconium nodes acted as tridentate ligands to the heterometal [69,70]. These M-MOFs had high catalytic activity towards a wide range of organic reactions including: hydrogenation, borylation, amination, and silation [44,70,71].…”

Porous framework-based hybrid materials for solar-to-chemical energy conversion: from powder photocatalysts to photoelectrodes

“…In recent studies, MOFs with SBUs composed of Earth-abundant elements were also introduced. Pi et al 126 for photocatalytic hydrogen production (Fig. 10a).…”