Zirconium terephthalate UiO-66 has aroused great interest in catalysis since it exhibits significant flexibility and compatibility for accommodating a high number of defects as well as exceptional thermal and chemical stability. Until now, many works have focused on the modulations of the Zr₆-oxo clusters in UiO-66 in terms of diverse synthesis, advanced characterizations, and their catalytic applications. To achieve high catalytic efficiency, it is still highly desired for rationally constructing and modulating the Zr₆-oxo clusters with exposed catalytic sites and diverse microenvironments for advanced catalysis. In this review, we provide a comprehensive summary of recent progress on the synthesis of defective UiO-66, qualitative and quantitative characterizations as well as a logical overview of heterogeneous catalytic applications over the past few years. Finally, the outlooks for the research paradigm of defective UiO-66 are discussed.

Compared with monometallic metal-organic frameworks (MOFs) that are synthesized by reacting inorganic metal ions or clusters with bidentate or multidentate ligands via hydrothermal or solvothermal methods, the construction of heterogeneous frameworks like at least two kinds of metal sites in the individual nodes is proved to be an effective way to modulate their properties for advanced catalysis, especially for selective catalysis and multifunctional catalysis. However, it is still very challenging to precisely characterize their microstructures and reveal the relationship among the composition, structure, and their performances. Therefore, it is necessary to summarize the recent progress on bimetallic MOFs for thermal catalysis. First, we summarize the synthesis strategies and characterization methods of bimetallic MOFs and their derivatives. Second, the application of bimetallic MOFs and their derivatives as catalysts in thermal catalysis is discussed, and the relationship among the active components, structures, and their properties is elucidated. Third, the potential challenges and prospects of bimetallic MOF based nanocatalysts are proposed. This review will bring some insights into the design and preparation of bimetallic MOFs based nanocatalysts in the future.

Selective hydrogenation of CO₂ to high value-added chemicals, not only gives an effective way to reduce the concentration of CO₂, but also provides the precursors to advance the industrial manufacturing of chemicals and fuels. With the well-defined reticular frameworks and flexible modifiability, metal-organic frameworks (MOFs) can be the ideal platform to construct the enabled catalysts for CO₂ hydrogenation, because they have shown the great potential for the enhancement of catalytic activity, the precise control of selectivity, and the excellent stability. In this review, we systematically summarize the recent advances in MOFs based catalysts for CO₂ hydrogenation towards diverse products. Firstly, synthesis strategies for different kinds of MOFs based catalysts are described. Secondly, selective hydrogenation of CO₂ towards CO and methane is discussed over various metal nanoparticles/MOFs composites. Thirdly, heterogenization and isolation of molecular catalysts by MOFs are elaborated for producing formic acid. Fourthly, selective hydrogenation of CO₂ toward methanol is discussed in terms of interface structures of Cu, Zn, and metal nodes of MOFs, the synergy between auxiliary sites and noble metal, and tandem catalytic systems of molecular catalysts and Lewis acid sites. Subsequently, the integration of multiple metal sites, promoters, and cocatalysts into MOFs is described for the selective hydrogenation of CO₂ to C₂₊ products. After those, the key issue about the stability of MOFs based catalysts for CO₂ hydrogenation reaction is discussed. Finally, the summary and perspective about MOFs based catalysts for selective CO₂ hydrogenation and mechanism research are proposed.

Ultrathin metal-organic framework (MOF) nanosheets are attracting great interest in catalysis due to their unique and intriguing two-dimensional (2D) features. Although many progresses have been achieved, it is still highly desirable to develop novel strategies for controllable synthesis of the well-defined ultrathin MOF nanosheets. Herein we report a polyvinylpyrrolidone (PVP)-assisted route to synthesize the ultrathin Ni-MOF nanosheets characteristic of 1.5 nm in thickness, in which PVP is reacted with 2-aminoterephthalic acid (H₂BDC-NH₂) via formation of C=N bond, followed by coordination with Ni²⁺ ions to form the ultrathin MOF nanosheets. Impressively, when used in the Knoevenagel condensation reactions of propane dinitrile with different aldehydes, ultrathin Ni-MOF nanosheets display the significantly enhanced catalytic activity and good stability in respect with the bulk Ni-MOF, mainly owing to the exposed active sites as well as facile mass transfer and diffusion of substrates and products.