Ultrathin Mesoporous Metal-Organic Framework Nanosheets

Designing 2D mesoporous metal-organic framework (MOF) nanosheets to overcome the limitations of bulk MOF counterparts, with a focus on enabling smooth mass transport, presents an attractive yet challenging endeavor. Here, a novel bottom-up interface-directed co-assembly method is presented for the synthesis of ultrathin 2D mesoporous UiO-66(Ce) nanosheets. The method utilizes an interface-directed co-assembly of amphiphilic perfluorooctanoic acid-induced lipid bilayers and spherical micelles from PS-b-PEO block copolymers to form unique 2D sandwich-like assemblies that guide the creation of 2D mesoporous UiO-66(Ce). The resultant 2D mesoporous UiO-66(Ce), with ≈23 nm pore diameters and a thickness that can be tuned from 3 to 150 nm, represents a substantial advancement in the application of MOFs for environmental remediation. As a model reaction, the U(VI) photoreduction benefits from the through-mesopores of its 2D morphology, which are absent in previously reported UiO-66(Ce), as they shorten the diffusion path, thereby improving mass transport and accessibility to active sites. This report demonstrates the significant role of existing mesopores in MOFs and the shape control of MOFs.