Effect of Linker Distribution in the Photocatalytic Activity of Multivariate Mesoporous Crystals

Abstract

The use of Metal-Organic Frameworks as crystalline matrices for the synthesis of multiple component or multivariate solids by the combination of different linkers into a single material has emerged as a versatile route to tailor the properties of single component phases or even access new functions. This approach is particularly relevant for Zr6-MOFs due to the synthetic flexibility of this inorganic node. However, the majority of materials is isolated as polycrystalline solids, which are not ideal to decipher the spatial arrangement of parent and exchanged linkers for the formation of homogeneous structures or heterogeneous domains across the solid. Here we use High-Throughput methodologies to optimize the synthesis of single crystals of UiO-68 and UiO-68-TZDC, a photoactive analogue based on a tetrazine dicarboxylic derivative. The analysis of the single linker phases reveals the necessity of combining both linkers to produce multivariate frameworks that combine efficient light sensitization, chemical stability and porosity, all relevant to photocatalysis. We use solvent assisted linker exchange reactions to produce a family of UiO-68-TZDC% binary frameworks, which respect the integrity and morphology of the original crystals. Our results suggest that the concentration of TZDC in solution controls the distribution of this linker in the sibling crystals for a random mixture or the formation of core-shell domains. We also demonstrate how the possibility of generating an asymmetric distribution of both linkers has a negligible effect on the electronic structure and optical bandgap of the solids but controls their performance for drastic changes in the photocatalytic activity towards proton or methyl viologen reduction.

Multivariate sodalite zeolitic imidazolate frameworks: a direct solvent-free synthesis

“…20 This versatility in both the metal and the ligand results in the modulation of properties such as the network exibility, which has shown to be fundamental for key properties, as in catalytic applications, 21,22 and indicates the possibility of ne-tuning the properties through a combination of ligands, 23 as reported in other families of MOFs. [24][25][26][27][28][29] However, other ligands that would normally form different structures are challenging to be incorporated into the SOD structure of ZIF-8 through a direct synthesis. In fact, the mixture of such ligands normally induces changes in the topology.…”

High Water Adsorption MOFs with Optimized Pore‐Nanospaces for Autonomous Indoor Humidity Control and Pollutants Removal

“…[49] Then eat PXRD patterns manifest good crystallinity and phase purity of all samples. Thef luorescence confocal images of UiO-67-4Me-NH 2 -38 % crystals with different sizes verify the homogeneous distribution of the mixed linkers across the whole crystal [50] (Supplementary Figure 15). Therefore,afamily of porous MOFs of UiO-67 prototype are obtained, and their octahedral-cage based pore-nanospaces are post-engineered and modified through fine tuning and mixing of functional groups with distinct hydrophilic/hydrophobic characters (Figure 2).…”

A Review of MOFs and Their Composites‐Based Photocatalysts: Synthesis and Applications

“…In general, the solvothermal route is considered to be an efficient strategy to prepare MOFs and their composites‐based photocatalysts because of the high yield, easy operation, low temperature as well as low pressure. [ 71–73 ] In the solvothermal reaction process, choosing a suitable solvent is very important. Up to now, lots of organic‐solvents are employed to fabricate MOFs and their composites, including N , N ‐dimethylformamide (DMF), [ 74–76 ] N , N ‐diethylformamide (DEF), [ 77,78 ] dimethylsulfoxide (DMSO), [ 79–81 ] toluene, etc.…”

“…In addition, many reports also demonstrated that the MOFs and their composites with different sizes (length, width or diameter) and morphologies can be synthesized through the solvothermal method, for instance, the polyhedral PCN‐250‐Fe 3 with a size of ≈13 µm, [ 72 ] the octahedral Uio‐68 and Uio‐68‐TZDC with the sizes from 10 to 20 µm, [ 73 ] the octahedral Co‐MOFs and Ni‐MOFs composite with an average size of ≈200 nm, [ 74 ] the rod‐shaped MIL‐53(Fe) with the length of ≈50 µm, [ 75 ] the octahedral MIL‐100(Fe) with the sizes from 100 to 200 nm, [ 79 ] etc.…”