Development of a bismuth-based metal-organic framework for photocatalytic hydrogen production

A novel 3 D bismuth-organic framework(called Bi-TBAPy) single crystal was synthesized by employing 1,3,6,8-tetrakis(p-benzoic acid)pyrene(H4TBAPy) as an organic linker. The study demonstrates that the Bi-TBAPy not only possesses good chemical stability and suitable band edge positions for promising photocatalytic H2 evolution, but it also exhibits a typical ligand-to-metal charge transfer for favorable charge separation. The photocatalytic H2 evolution rates on the as-obtained Bi-TBAPy with different cocatalysts modified were examined with triethanolamine as the sacrificial reagent. Based on this, the hydrogen evolution rate of 140 μmol h-1 g-1 was obtained on the optimized sample with a loading of 2 wt% Pt as a cocatalyst. To the best of our knowledge, this is the first bismuth-based metal-organic framework(MOF) that functions as an effective photocatalyst for photocatalytic water reduction. Our study not only adds a new member to the family of photocatalyst materials, but also reveals the importance of cocatalyst modification in improving photocatalytic activity of MOFs.

Water-stable Mn-based MOF nanosheet as robust visible-light-responsive photocatalyst in aqueous solution

Development of visible-light-responsive metal-organic frameworks(MOFs) for promising solar energy conversion has inspired continuous interest, but it still suffers from poor stability especially in aqueous solution and/or under photoirradiation due to their relatively labile coordination bonds. Herein, a new synthesized layered Mn-based MOF(Mn-TBAPy-BK) and its exfoliated twodemensional nanosheets(Mn-TBAPy-NS) are revealed to be highly stable no matter in aqueous solution with wide p H region or under visible light irradiation. As expected, the exfoliated Mn-TBAPy-NS exhibits enhanced surface area, shortened charge transfer distance, and superior charge separation with respect to the bulk one. Moreover, the as-obtained nanosheets can be employed as effective building block for nanocomposite and heterostructure assembly to further promote charge separation as well as solar hydrogen production from aqueous solution under visible light. The finding of water stable MOF nanosheet under visible light demonstrates its promising future for solar energy conversion.