Molecular Encapsulation of Trimeric Chromium Carboxylate Clusters in Metal–Organic Frameworks and Propylene Sorption

Oxo-bridged trimeric chromium acetate clusters [Cr₃O(OOCCH₃)₆(H₂O)₃]NO₃ have been encapsulated for the first time in the mesoporous cages of the chromium terephthalate MIL-101(Cr). The isolated clusters in MIL-101(Cr) have increased affinity towards propylene compared to propane, due to generation of a new kind of pocket-based propylene-binding site, as supported by DFT calculations.     

Nickel Oxide/Graphene Composites: Synthesis and Applications

Nickel oxide (NiO) has emerged as one of the most promising transition-metal oxides (TMOs) for electrochemical capacitors, batteries, catalysis, and electrochromic films, owing to its cost-effectiveness, abundance, and well-defined electrochemical properties. Recent studies have identified that mixing NiO with graphene or graphene derivatives results in novel composites with synergistic effects and superior electrochemical performance. This review summarizes the latest advances in composites of NiO with graphene or graphene derivatives. The synthetic strategies, morphologies, and electrochemical performance of these composites are introduced, as well as their electrochemical applications in supercapacitors, batteries, sensors, catalysis, and so forth. Finally, tentative conclusions and assessments regarding the opportunities and challenges for the future development of these composites and other TMOs/graphene or graphene-derived composites are presented.     

Organosulfonate Counteranions—A Trapped Coordination Polymer as a High-Output Triboelectric Nanogenerator Material for Self-Powered Anticorrosion

Selection of the friction electrode materials is crucial to the performance of a triboelectric nanogenerator (TENG). In the present study, a metal–organic coordination complex containing organosulfonate counteranions with electron-donating ability was synthesized through the coordination-driven self-assembly approach under mild reaction conditions and was chosen as a positive electrode material to construct a triboelectric nanogenerator, exhibiting high-output performance with a peak value of short circuit current density of 98.6 μA and an output voltage of 1180 V. As a practical application, it was shown to light up 1488 commercial green LEDs and power an anticorrosion system device to protect metals from corrosion.     

Two-Dimensional MOF and COF Nanosheets: Synthesis and Applications in Electrochemistry

Metal–organic framework (MOF) and covalent organic framework (COF) nanosheets are a new type of two-dimensional (2D) materials with unique design principles and various synthesis methods. They are considered ideal electrochemical devices due to the ultrathin thickness, easily tunable molecular structure, large porosity and other unique properties. There are two common methods to synthesize 2D MOF/COF nanosheets: bottom-up and top-down. The top-down strategy mainly includes ultrasonic assisted exfoliation, electrochemical exfoliation and mechanical exfoliation. Another strategy mainly includes interface synthesis, modulation synthesis, surfactant-assisted synthesis. In this Review, the development of ultrathin 2D nanosheets in the field of electrochemistry (supercapacitors, batteries, oxygen reduction, and hydrogen evolution) is introduced, and their unique dimensional advantages are highlighted.     

Investigation of unstable motion characteristics of vacuum arc cathode spots between transverse magnetic field contacts

With the improvement of the current level of power grids, the requirements of the opening level of the vacuum switches are also increasing. Vacuum arc cathode spots provide steam and electrons and, to a certain extent, determine the opening capacity of the vacuum switch. In this paper, a vacuum arc cathode spot research platform based on the de-mountable vacuum chamber is constructed. The characteristics of the vacuum arc cathode spots under the transverse magnetic field (TMF) contacts are assessed by a high-speed charge coupled device. The experimental results show that the cathode spot diffusion process can be divided into three processes through cathode spot distribution, arc voltage and current: initial diffusion stage of cathode spots, unstable motion stage of cathode spots, and extinguishing stage. The motion mode of cathode spots during unstable motion stage can be divided into cathode spots group stagnation (CSGS) to multi-cathode jet (MCJ) switch mode, cathode spots group motion (CSGM) to MCJ switch mode, CSGM mode, and MCJ mode. The effects of peak current and contact diameter on unstable motion mode were analysed.     

The Influence of N,N-Dimethylformamide on Dispersion of Multi-Walled Carbon Nanotubes

Russian Journal of Physical Chemistry A - Preparation of highly homogeneous disperse ions multi-walled carbon nanotubes (MWCNTs) has vital effect on their applications. In this research, the...     

Suppressing Strong Exciton–Phonon Coupling in Blue Perovskite Nanoplatelet Solids by Binary Systems

Quasi-two-dimensional (2D) perovskites are promising candidates for light generation owing to their high radiative rates. However, strong exciton–phonon interactions caused by mechanical softening of the surface act as a bottleneck in improving their suitability for a wide range of lighting and display applications. Moreover, it is not easily available to tune the phonon interactions in bulk films. Here, we adopt bottom-up fabricated blue emissive perovskite nanoplatelets (NPLs) as model systems to elucidate and as well as tune the phonon interactions via engineering of binary NPL solids. By optimizing component domains, the phonon coupling strength can be reduced by a factor of 2 driven by the delocalization of 2D excitons in out-of-plane orientations. It shows the picosecond energy transfer originated from the Förster resonance energy transfer (FRET) efficiently competes with the exciton–phonon interactions in the binary system.     

Continuous Electrochemical Synthesis of Iso-Coumarin Derivatives from o-(1-Alkynyl) Benzoates under Metal- and Oxidant-Free

A non-oxidant and metal-free strategy for synthesizing iso-coumarin by using a continuous electrochemical microreactor to initiate an oxidative cyclization reaction of o-(1-alkynyl) benzoate and radicals. This efficient and clean continuous electrosynthesis method not only avoids the complicated gas protection operation and production of by-products in the batch processes, but also help to overcome the difficulty that batch metal catalysis and electrocatalysis are difficult to scale up, and has the potential for pilot-scale experiment.     

Topography guiding the accelerated and persistently directional cell migration induced by vaccinia virus

The rapid transmission of vaccinia virus(VACV)in vivo is thought to be closely related to the cell migration induced by it.Cell migration involved in dynamic changes of cell-substrate adhesion and actin cytoskeleton organization,which can influence by the micro/nano-scale topographic structures that cells are naturally exposed to via contact guidance.However,migration behaviors of VACV-infected cells exposed to topographic cues are still unknown.Herein,we designed an open chip with microgrooved poly(dimethyl siloxane)(PDMS)substrate to explore the topography roles in VACV-induced cell migration.Differed from the random cell migration observed in traditional scratch assay on planar substrate,VACV-infected cells had a tendency to persistently migrate along the axis parallel to microgroove with increased velocity.Moreover,infected cells exhibited a dominant elongated protrusion aligned to the micro-grating axis compare to the shorter lamella extended in any direction on smooth substrate.Interestingly,the Golgi complex preferred to relocate behind the nucleus confined within the micro-grating axis in majority of infected migratory cells.The directional polarization of cells embodied in protrusion formation and Golgi reorientation was responsible for the directionally persistent migration behaviors induced by VACV on microgrooved substrate.Infected cells response to substrate topography,causing the actin-filled stretched protrusion containing numerous virions and accelerated movement is likely to facilitate direct and rapid spread of VACV.This work opens a window for us to understand the migration behaviors of infected cells in vivo,and also provides a cue for revealing the relationship between virus-induced cell migration and virus rapid spread.     

High effects of smoke suppression and char formation of Ni?Mo/Mg(OH)2 for polypropylene

The Ni? Mo/Mg(OH)₂ (NMM) hybrid as an efficient flame retardancy and smoke suppression composite for polypropylene (PP) was synthesized through Ni? Mo co‐precipitation on the surface of Mg(OH)₂ (MH) hexagonal nanosheets. Compared to PP/MH, PP/NMM exhibited excellent smoke suppressing and flame retardancy on the heat release rate, total heat release, smoke production rate, total smoke production, CO production rate and total CO production with the same loading. The reduced hazard of PP/NMM was mainly attributed to the high physical barrier effect of compact char residues on heat, smoke and combustible gas. The mechanism study indicated that multiwalled carbon nanotubes (MWCNTs) generated from the catalytic carbonization of PP by the Ni? Mo compound could play the role of “rebar” to strengthen the char residues, avoid the generation of cracks and form highly compact char layer. Furthermore, MgO could facilitate the production of MWCNTs through changing the pyrolysis process of PP and increasing the reaction time between pyrolysis gas and Ni? Mo compound. Hence, the new Ni? Mo/MH catalyst hybrid may explore the potential for solving the tough problem of the flammability and heavy smoke of the polyolefins system.