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Insights into the relationship between the crystal structure and activity of metal–organic frameworks (MOFs) are meaningful to investigate the potential properties of pristine MOFs for targeted catalytic reactions. Herein, we develop a high-efficiency method for boosting the oxidative desulfurization (ODS) activity of Ti-MOF in the presence of H+. The ODS activity of pristine Ti-MOF prepared via a solvothermal approach is very poor at a low reaction temperature but can be enhanced in the presence of H+. Ti-MOF in the presence of H+ shows ultrahigh ODS activity that can eliminate 1000 ppm sulfur after 7 min at 30 °C with no catalytic activity loss after recycling 11 times. The turnover frequency value reaches 12.4 h−1 at 30 °C, surpassing all the previously reported Ti-MOFs as ODS catalysts even at high temperatures. Characterization and quenching experimental results indicate that more uncoordinated Ti sites can be formed from slight damage to the structure of Ti-MOF during the catalytic reaction, and such exposed Ti sites can easily react with H+ and H2O2 to form Ti–hydroperoxo active species that determine the upgradation of ODS activity. This work provides a significant way to upgrade the catalytic activity of pristine Ti-MOFs for future application. [ABSTRACT FROM AUTHOR]

Functionalized metal–organic frameworks (MOFs) have been used in a wide range of applications. Although the development of functionalized MOFs with plentiful open metal sites (defects) provides an avenue for targeted reactions, creating such defects remains challenging. Herein, a UiO-type MOF with hierarchical porosity and plentiful Zr–OH/OH2 sites (capping 35% Zr coordination sites) was synthesized within 40 min by a solid-phase synthesis route without the use of solvent and template. The optimal sample converted 5.7 mmol benzaldehyde to (dimethoxymethyl)benzene within 2 min at 25 °C. The turnover frequency number and activity per unit mass reached 2380 h−1 and 8568 mmol g−1 h−1, respectively, outperforming all previously reported catalysts at room temperature. This excellent catalytic activity was correlated with the defect density in functionalized UiO-66(Zr) and the accessibility of plentiful Zr–OH/OH2 sites as acid sites. [ABSTRACT FROM AUTHOR]

UiO-66(Zr) as a member of metal–organic frameworks (MOFs) is an attractive porous material mainly because of its good structural stability and abundant metal Zr centers. Therefore, the accelerated and scalable synthesis of UiO-66(Zr) is of practical importance under solvent-free conditions. In this work, we report that such a synthesis has been successfully realized with the assistance of inorganic salts. During the synthesis, the influence of some parameters including the addition amount of inorganic salt, crystallization temperature and time, and the type of inorganic salt was investigated in detail. The characterization results reveal that UiO-66(Zr) with a large surface area (969 m2 g−1) and high yield (∼92%) can be obtained with the aid of NaCl (in a molar ratio of Zr/Na = 4) in a crystalline time of 3 h at 130 °C. What's more, 5.7 g UiO-66(Zr) was produced in a 15 mL autoclave, which is 100 times higher than that (below 50 mg) obtained by a solvothermal method. This result suggests that the synthetic process is conducive to large-scale production. In addition, the approach may be also extended to prepare functionalized UiO-66(Zr) materials like nitro- and amino-functionalized UiO-66(Zr). [ABSTRACT FROM AUTHOR]

Catalytic oxidative desulfurization (ODS) of fuel oil has received much attention. For this, the synthesis of a highly efficient ODS catalyst has been strongly pursued. Polyoxometalates (POMs) as active centers have been studied for ODS reactions. However, generally the obtained POM catalysts exhibited ordinary catalytic ODS performance mainly due to the role of single active sites. Moreover, the synthesis needs to be completed with the addition of solvent. In this work, we report a new approach to prepare highly efficient ODS catalysts with POM sites. This process can be simply realized by the combination of a common POM (H3PW12O40) and a stable metal–organic framework (MOF) material UiO-66(Zr) without the addition of solvent. More importantly, it is found that polyoxometalate encapsulated in UiO-66(Zr) possesses hierarchical porosity and double active sites. As a result, the catalyst exhibited extraordinary catalytic activity by using H2O2 as an oxidant in the ODS reactions of benzothiophene, dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene. The turnover frequency (TOF) for the removal of DBT reached 293 h−1 at room temperature, which is much higher than that of the reported catalysts. Such outstanding catalytic performance could be mainly attributed to easy accessibility of active sites and the existence of two types of active centers in polyoxometalate species and defective UiO-66(Zr). [ABSTRACT FROM AUTHOR]

MIL-100(Fe) is one of the important metal–organic frameworks due to its fascinating physicochemical properties. Generally, MIL-100(Fe) was synthesized under the conditions of adding HF and solvent. Here, we report that MIL-100(Fe) can be facilely synthesized without the addition of solvent and HF. More importantly, this approach can produce MIL-100(Fe) with a high yield of 93%. Additionally, the obtained MIL-100(Fe) exhibited good catalytic performance in the acetalization of benzaldehyde with methanol. This catalyst can still maintain the initial catalytic activity after five cycles. [ABSTRACT FROM AUTHOR]

In this work, three isomeric benzenedicarboxylates, 1,2-benzenedicarboxylic acid (o-H2bdc), 1,3-benzenedicarboxylic acid (m-H2bdc), and 1,4-benzenedicarboxylic acid (p-H2bdc) have been utilized as the ancillary ligands to perform a systematic study on the structural diversity of mixed-ligand frameworks. The solvothermal reactions of Co(NO3)2 with these aromatic acids and the primary ligand 4,4′-bis(imidazolyl)biphenyl (bibp) afford three novel coordination polymers, {[Co6(bibp)3(o-bdc)6(H2O)](CH3CN)1.5}∞ (1), [Co(bibp)(m-bdc)]∞ (2), and [Co(bibp)(p-bdc)]∞ (3). Owing to the different orientations of the carboxylate groups, the benzenedicarboxylates adopt various bridging modes to connect the CoII ions into a series of 1D carboxylate⌒cobalt architectures based on the 1D chain, binuclear and single-ion magnetic units, respectively. These 1D architectures are further decorated by the bibp ligand to afford a 1D belt for 1, 2D double-bridging (4,4) sheet for 2, and an unusual 3D dmp framework for 3. Significantly in 3, three equivalent frameworks are interlocked with each other to represent an unprecedented three-fold interpenetrating dmp network. The structural diversity indicates that the benzenedicarboxylate plays an essential role in the assembly of mixed-ligand frameworks, and the orientation of the carboxylate group exerts an important influence on the nucleation, dimensionality and also interpenetration. Furthermore, the magnetic properties of 1 and 2 have been studied by fitting the experimental data as possible, and the magneto-structural correlation of 2 has also been well discussed. Importantly, CoO and Co3O4 were obtained from the controllable thermolysis of crystals of 1via simple calcination treatment under different gas environments. The as-synthesized cobalt oxides display good crystallinity and appear as micro- or nanoparticles, which can be applied as supercapacitor electrodes as demonstrated by their energy storage performance in 2 M KOH electrolyte. [ABSTRACT FROM AUTHOR]

In this work, a dextran modified PDMS microfluidic ELISA device was fabricated. The dextran functionalization was conducted with a simple, economic and fast flow-through process in a fabricated PDMS microfluidic device, and demonstrated significant enhancement of hydrophilicity and efficient covalent immobilization of proteins on the PDMS microchannel surface. The device was used to simultaneously detect multiple important biomarker IL-5, HBsAg, and IgG, showing a limit of detection of 100 pg mL−1and a dynamic range of 5 orders of magnitude, which significantly improved the performance of the reported hydrophobic and plasma-treated hydrophilic PDMS flow-through immunoassay devices. The fabricated PDMS device demonstrated its capability for colorimetric detection of proteins through direct observation by human eyes. Thus, this work not only demonstrates great potential to fabricate an economical and sensitive lab-on-chip system for high throughput screening of various infectious diseases, but also provides an opportunity to develop a portable microfluidic ELISA device viahuman eye examination for heath point-of-care services. [ABSTRACT FROM AUTHOR]

In this paper, a new microfluidic array device has been fabricated with screen printing technology. In contrast to traditional microfabrication processes, our method is simple, inexpensive and also suitable for mass production. The device is used for sandwich-type electrochemical immunoassay, in which probes are covalently attached to the electrode surface via electropolymerized polypyrrole propylic acid (PPA) film. This novel microfluidic system enables the whole array preparation and detection processes, including the probe immobilization, sample injection, enzyme incubation and electrochemical detection, to be conducted in the sealed microchannels. For a demonstration, mouse IgG is selected as the target analyte and its detection is realized by sandwich ELISA with goat anti-mouse IgG, rat anti-mouse IgG (conjugated to alkaline phosphatase) and p-aminophenyl phosphate (PAPP) as the primary antibody, second antibody, and enzyme substrate, respectively. A detection limit of 10 ng mL−1 (67 pM) is achieved with a dynamic range of 100 ng mL−1–10 μg mL−1. In addition, anti-goat IgG is also immobilized as an alternative probe to test mouse IgG in the solution, in order to demonstrate the multiplexing capability as well as the specificity of the device. As expected, the electrochemical responses are much lower than that using anti-mouse IgG as the probe, indicating good selectivity of the immunoassay device. These results indicate a great promise toward the development of miniaturized, low-cost protein biochips for clinical, forensics, environmental, and pharmaceutical applications. [ABSTRACT FROM AUTHOR]