Reviewing the recent advances in 2D MOF nanosheets-based photocatalysts, the choice of photosensitizers is limited. A large number of 2D MOF catalysts are based on porphyrin derivatives, mostly 5, 10, 15, 20-tetraphenylporphyrins. However, the photophysical properties of porphyrins being well-studied, their capable catalytic reactions are typically limited to systems that utilize 1O2 generation, CO2 reduction, H2 and O2 production. To expand the scope of MOF catalytic capabilities, different photo-responsive linkers need to be investigated. Phenothiazine (PTH) is a sulfur and nitrogen-based photo-responsive heterocycle. This molecule shows great reductive potential upon light excitation ( = -2.1 V vs. saturated calomel electrode). By being crafted into a MOF, PTH gains extra stability and resistance to active chemical environments. This work showcases the benefit of MOFs as platforms for catalyst heterogenization, utilizing the facile surface chemistry of the 2D MOF to anchor an organic catalyst and produce a heterogenous system cable of being readily recycled. In this work, a photosensitive ligand, H3L1 is developed from PTH. It was readily crafted into MOF structures. At first, interpenetrated MOF and layer-clustered MOF structures were initially obtained, separately. As predicted, the catalytic performance of the H3L1 3D MOFs was merely passable. But the presence of Zr6-H3L1 layers in the 3D structures led to the idea of dimension reduction to obtain 2D MOF nanosheets with more accessible photocatalytic sites while still maintaining chemical stability. Both bottom-up and top-down (exfoliation) pathways were demonstrated, and the 2D MOF nanosheet, PCN-641-NS, was subsequently obtained. The nanosheets showed excellent performance as photocatalysts in the photoborylation of aryl halides. The reaction mechanism was further studied to illustrate the role of PCN-641-NS in the reaction. Furthermore, post-synthetic modifications of the linkers were attempted. This shows the potential benefit of the PCN-641-NS platform as a method for developing multifunctional or tandem catalytic systems.

From 3-D to 2-D: A self-assembled zirconium nanosheet with intrinsic photocatalytic activity

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.