Construction of CuII Defects on CuCl Nanoparticles in Metal-Organic Frameworks toward Composite Catalysts with Superior Activity.

Metal-organic frameworks (MOFs) represent an ideal platform for the construction of highly active composite catalysts. However, loading metastable and/or multicomponent metal compounds into MOFs remains a synthetic bottleneck due to the great challenge of keeping the guest and matrix intact during the preparation of a composite. In this work, we develop a new impregnation reduction surface modification (IRSM) strategy to give a new composite catalyst CuCl@MIL-101(Cr), which is successfully postmodified by in situ construction of CuII defects on the surface of loaded CuCl inside MOF pores, leading to the new composite material CuII/CuI@MIL-101(Cr). The new dual-component composite catalyst exhibits a hierarchical structure and superior catalytic activity in C-C homocoupling of arylboronic acids under green conditions. This study presents a facile strategy for improving the catalytic activity by constructing defects on the surface of MOF-based catalysts as well as for forming multiple-component composite materials.

Controlled Thermal Conversion Strategy to Provide Metal-Organic Framework-Supported Composite Catalysts.

Metal-organic framework (MOF)-supported metal/metal compound nanoparticles (NPs) have emerged as a new class of composite catalysts. However, huge challenges prevail in placing such NPs in the MOF pores because of the poor solubility of metal/metal oxides, limited availability of suitable precursors, metastable attribute of given metal ions, and lower thermal stability of MOFs compared to conventional porous materials. Based on the difference between the thermal stability of the precursor and MOFs, we successfully developed a controlled thermal conversion (CTC) method to load cobalt(II) oxide (CoO) NPs into the framework of MOF (MIL-101) to conveniently obtain a composite catalyst, CoO@MIL-101, which is a very rare example of pure CoO NP-loaded composite catalyst that shows excellent catalytic activity in the selective oxidation of benzyl alcohol. This CTC strategy opens up a pathway for impregnating MOF supports with specific NPs, which is further confirmed by preparing the first CuBr@MOF-type composite catalyst.

Conversion of CO2 to Heterocyclohexenol Carboxylic Acids through a Metal-Organic Framework Sponge.

The conversion of CO2 into high value-added chemical products is the focus of current scientific research. We make use of the specific porous structure of nanosized metal-organic frameworks (MOFs) loading the highly active yet metastable nano Cu2O to catalyze the conversion of CO2 into a series of high value-added bioactive pyridone/pyrone-3-carboxylic acid products via heterocyclic 4-hydroxy-2-pyridones/pyrones, which exhibit high activity, selectivity, and reusability. Nano MOF sponge-covered metastable nanoparticles (NPs) converting CO2 into high value-added bioproducts provide a facile "dual-side surfactant" strategy, a highly efficient composite catalyst, and a practicable pathway not only for the sustainable use of CO2 but also for environment-friendly production of bioproducts.

MOFs-Based Catalysts Supported Chemical Conversion of CO2.

The dramatic increase in atmospheric carbon dioxide (CO2) concentrations has attracted human attention and many strategies about converting CO2 into high-value chemicals have been put forward. Metal-organic frameworks (MOFs), as a class of versatile materials, have been widely used in CO2 capture and chemical conversion, due to their unique porosity, multiple active centers and good stability and recyclability. Herein, we focused on the processes of chemical conversion of CO2 by MOFs-based catalysts, including the coupling reactions of epoxides, aziridines or alkyne molecules, CO2 hydrogenation, and other CO2 conversion reactions. The synthesized methods and high catalytic activity of MOFs-based materials were also analyzed systematically. Finally, a brief perspective on feasible strategies is presented to improve the catalytic activity of novel MOFs-based materials and explore the new CO2 conversion reactions.

Design of a Zn-MOF biosensor via a ligand "lock" for the recognition and distinction of S-containing amino acids.

Two new 2D Zn(ii) metal-organic frameworks (MOFs) {[Zn2(L)2(µ2-O)(H2O)3]·3DMA}n (Zn-1) and [Zn2(L)2(2,2'-bipy)(µ2-O)(H2O)2]n (Zn-2) (H2L = 2,5-thiophene dicarboxylic acid, bipy = 2,2'-dipyridyl) were designed and synthesized. Through the strategy of introducing bipy as a "lock", Zn-1 was transferred to Zn-2via a crystal-to-crystal process, which showed significantly enhanced solvent and air stability compared to that of Zn-1. Without post modification, Zn-2 was used as an electrode modified material to construct sensors for the electrochemical recognition and distinction of S-containing amino acids, including l-cysteine, l-methionine and l-cystine.