High‐precision size recognition and separation in synthetic 1D nanochannels

Covalent organic frameworks (COFs) allow elaborate manufacture of ordered one‐dimensional channels in the crystal. We defined a superlattice of COFs by engineering channels with a persistent triangular shape and discrete pore size. We observed a size‐recognition regime that is different from the characteristic adsorption of COFs, whereby pore windows and walls were cooperative so that triangular apertures sorted molecules of one‐atom difference and notch nanogrooves confined them into single‐file molecular chains. The recognition and confinement were accurately described by sensitive spectroscopy and femtosecond dynamic simulations. The resulting COFs enabled instantaneous separation of mixtures at ambient temperature and pressure. This study offers an approach to merge precise recognition, selective transport, and instant separation in synthetic 1D channels

Hybrid crystals comprising metal-organic frameworks and functional particles : synthesis and applications

Hybrid crystals containing encapsulated functional species exhibit promising novel physical and chemical properties. The realization of many properties critically depends on the selection of suitable functional species for incorporation, the rational control of the crystallinity of the host materials, and the manipulation of the distribution of the encapsulated species; only a few hybrid crystals achieve this. Here, a novel synthetic method enables the encapsulation of functional species within crystalline metal–organic frameworks (MOFs). Various kinds of single-crystalline MOFs with incorporated particles are presented. The encapsulated particles can be distributed in a controllable manner, and the hybrid crystals are applied to the heterogeneous catalysis of the reduction of nitroarenes. These findings suggest a general approach for the construction of MOF materials with potential applications; by combining species and MOFs with suitable functionalities, new properties—not possible by other means—may arise

Grinding of silicon wafers using an ultrafine diamond wheel of a hybrid bond material

An ultrafine diamond wheel of a mesh size of 12,000 was fabricated by using a hybrid bond material, which consists of silicon carbide, silica and alumina. The employment of the newly developed wheel enabled excellent performance during grinding of silicon wafers. An extremely smooth surface of an average roughness of 0.6 nm was achieved. TEM examinations showed that the total thickness of the defected layer was less than 60 nm

Synthesis and self-assembly of monodispersed metal-organic framework microcrystals

How to make super latt(ic)e: Monodispersed octahedral microcrystals of a zirconium-carboxylate metal-organic framework (MOF), UiO-66, were synthesized, under optimized experimental conditions, by using acetic acid as a modulator. Due to their uniform size and shape, the obtained MOF microcrystals can be assembled not only into large-area two-dimensional (2D) monolayers with oriented facets through a liquid-air interfacial assembly technique, but also into long-range three-dimensional (3D) superlattices by sedimentation

Mesoporous Silica Gel–Based Mixed Matrix Membranes for Improving Mass Transfer in Forward Osmosis: Effect of Pore Size of Filler

The efficiency of forward osmosis (FO) process is generally limited by the internal concentration polarization (ICP) of solutes inside its porous substrate. In this study, mesoporous silica gel (SG) with nominal pore size ranging from 4–30 nm was used as fillers to prepare SG-based mixed matrix substrates. The resulting mixed matrix membranes had significantly reduced structural parameter and enhanced membrane water permeability as a result of the improved surface porosity of the substrates. An optimal filler pore size of ~9 nm was observed. This is in direct contrast to the case of thin film nanocomposite membranes, where microporous nanoparticle fillers are loaded to the membrane rejection layer and are designed in such a way that these fillers are able to retain solutes while allowing water to permeate through them. In the current study, the mesoporous fillers are designed as channels to both water and solute molecules. FO performance was enhanced at increasing filler pore size up to 9 nm due to the lower hydraulic resistance of the fillers. Nevertheless, further increasing filler pore size to 30 nm was accompanied with reduced FO efficiency, which can be attributed to the intrusion of polymer dope into the filler pores.MOE (Min. of Education, S’pore)Published versio

Engineering ZIF-8 thin films for hybrid MOF-based devices

Patterned metal-organic framework, ZIF-8 thin films can be generated by using standard photolithography or via selective growth with the aid of microcontact printing. The alternate chemical deposition (of ZIF-8) and physical deposition (of metallic materials) allow the insertion of metal layers in the ZIF-8 film that could serve as multifunctional chemical sensors for vapors and gases

Interweaving metal-\u80\u93organic framework-templated Co-\u80\u93Ni layered double hydroxide nanocages with nanocellulose and carbon nanotubes to make flexible and foldable electrodes for energy storage devices

Metal–organic frameworks (MOFs) and nanocellulose represent emerging and traditional porous materials, respectively. The combination of these two materials in specific ways could generate novel nanomaterials with integrated advantages and versatile functionalities. This study outlines the development of hierarchical porous and conductive nanosheets based on zeolitic imidazolate framework-67 (ZIF-67, a Co-based MOF)-templated Co–Ni layered double hydroxide (LDH) nanocages, Cladophora cellulose (CC) nanofibers, and multi-walled carbon nanotubes (CNTs). The LDH–CC–CNT nanosheets can be used as flexible and foldable electrodes for energy storage devices (ESDs). The electrodes are associated with a high areal capacitance of up to 1979 mF cm−2 at a potential scan rate of 1 mV s−1. A flexible, foldable, and hybrid ESD is assembled from LDH–CC–CNT and CC–CNT electrodes with a PVA/KOH gel. The entire device has an areal capacitance of 168 mF cm−2 and an energy density of 0.6 mW h cm−3 (60 μW h cm−2), at a power density of 8.0 mW cm−3 (0.8 mW cm−2). These promising results demonstrate the potential of using MOFs and sustainable cellulose in flexible, foldable electronic energy storage devices.De 2 första författarna delar förstaförfattarskapet.</p

'Are there good and bad divorces?' The impact of the divorce process on the well-being of ex-partners after separation

Silica gel (SG)–polyacrylonitrile (PAN) composite forward osmosis (FO) membranes have been synthesized and characterized in the present work. The incorporation of SG particles into the PAN support layer significantly changed its water permeability and salt rejection rate. In the range of 0.25–1.0 wt.% SG loading, water permeability of membranes were enhanced after the embedment of SG, most likely due to the both porous nature of SG and the enhanced substrate porosity. However, a reduction in both water permeability and salt rejection was observed if further increase in SG loading (2.0 wt.%), possibly as a result of the agglomeration of SG. The most permeable SG–PAN FO membrane (M1.00, with 1.0 wt.% SG loading) had a significantly higher water permeability compared to the control pure PAN FO membrane (M0.00). This membrane achieved high FO water fluxes of >100 L/m2 h was achieved by using the 1 M MgCl2 as the draw solution (DS) and 0–10 mM NaCl as the feed solution (FS). To the best knowledge of the authors, this is the first study reporting the development and application of SG–PAN mixed matrix FO membranes (MMMs) based on layer-by-layer assembly

Well-dispersed and size-controlled supported metal oxide nanoparticles derived from MOF composites and further application in catalysis

Supported metal oxide nanoparticles are important in heterogeneous catalysis, however, the ability to tailor their size, structure, and dispersion remains a challenge. A strategy to achieve well-dispersed and size-controlled supported metal oxides through the manageable growth of a metal organic framework (Cu–BTC) on TiO2 is described here, followed by pyrolysis