Herein we report a novel, ozone-based method for post-synthetic generation of mesoporosity in metalorganic frameworks (MOFs). By carefully selecting mixed-ligand Zr-fcu-MOFs based on organic ligand pairs in which one ligand has ozone-cleavable olefin bonds and the other ligand is ozoneresistant, we were able to selectively break the cleavable ligand via ozonolysis to trigger fusion of micropores into mesopores within the MOF framework. This solid-gas phase method is performed at room-temperature and, depending on the cleavable ligand used, the resultant ligand-fragments can be removed from the ozonated MOF by either washing or sublimation. Compared to the corresponding highly-microporous starting MOFs, the highly-mesoporous product MOFs exhibit radically distinct gas sorption properties. Herein we report application of our post-synthetic strategy to selectively and quantitatively cleave and remove the organic ligands in two multivariate (MTV) 23 Zr-fcu-MOFs (Figure 1), thereby affecting their adsorption performance in gas uptake. By controlling the ozone inert/active ratio of ligands in these MOFs, we were able to control the final number of defects in their structures.

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We describe solid-gas phase, single-crystal-to-single-crystal, postsynthetic modifications of a metal-organic framework (MOF). Using ozone, we quantitatively transformed the olefin groups of a UiO-66-type MOF into 1,2,4-trioxolane rings, which we then selectively converted into either aldehydes or carboxylic acids.

A Zr-based metal-organic framework (MOF) catalyst, Pt/Au@Pd@UIO-66, is assembled, where UIO-66 is Zr O (OH) (BDC) (BDC = 1,4-benzenedicarboxylate). The gold nanoparticles (NPs) act as the core for the epitaxial growth of Pd shells, and the core-shell monodispersed nanosphere Au@Pd is encapsulated into UIO-66 to control its morphology and impart nanoparticle functionality. The microporous nature of UIO-66 assists the adsorption of Pt NPs, which in turn enhances the interaction between NPs and UIO-66, favoring the formation of isolated and well-dispersed Pt NP active sites. This MOF exhibits high catalytic activity and CO product selectivity for the reverse-water-gas-shift reaction in a fixed-bed flow reactor.

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High-quality single crystals are essentially needed for the investigation of the novel bulk properties of unconventional superconductors. The availability of such crystals grown by the floating-zone method has helped to unveil the unconventional superconductivity of the layered perovskite Sr 2 RuO 4 , which is considered as a strong candidate of a topological spin-triplet superconductor. Yet, recent progress of investigations urges further efforts to obtain ultimately high-quality crystalline samples. In this paper, we focus on the method of preparation of feed rods for the floating-zone melting and report on the improvements of the crystal growth. We present details of the improved methods used to obtain crystals with superconducting transition temperatures T c that are consistently as high as 1.4 K, as well as the properties of these crystals.Despite the key experimental results supporting spin-triplet pairing [19][20][21][22][23], such a first-order transition is difficult to explain within the context of spin-triplet superconductivity. This first-order transition becomes second order when the T c is suppressed below 1.45 K, which corresponds to an impurity level of~50 ppm [10]. Thus, pristine samples with impurity levels less than 10 ppm are required in order to deepen our knowledge of the superconducting state of Sr 2 RuO 4 .Recent innovations in the design of uniaxial-stress cells enables the T c of Sr 2 RuO 4 to be enhanced up to 3.5 K when the stress is along the crystalline [100] direction [24][25][26][27]. The origin of this enhancement of T c is attributed to the Fermi-level crossing of the van-Hove singularity in one of the three quasi-two-dimensional Fermi surfaces. It is hoped that detailed investigations of this phenomenon will lead to the clarification of the superconducting symmetry and mechanism in Sr 2 RuO 4 . The T c enhancement has actually been known for many years in the eutectic crystals of Sr 2 RuO 4 with micron-size metallic Ru platelets, which introduce strong strains in Sr 2 RuO 4 near the interfaces [28][29][30]. In order to investigate the strain-induced superconducting phase, high-quality Ru-inclusion free single crystals of Sr 2 RuO 4 with a specific in-plane crystalline direction are in demand.In this study, we examine how we can further improve the quality of crystals of Sr 2 RuO 4 grown by the floating-zone method with an infrared image furnace. The floating-zone technique has been used to produce high-quality crystals of relatively large size useful for most experimental purposes including inelastic neutron scattering. Because the technique is essentially crucible-free, it can be used to achieve the minimum possible impurity levels. The floating-zone technique has been used for the successful crystal growth of Sr 2 RuO 4 [31], as well as other ruthenates [32][33][34][35][36][37]. Previous reports mainly describe optimization of the atomic compositions of the feed rod and various parameters of the final growth process. On the other hand, there are a number of processes (from pow...

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