A sensor with a red‐emission signal is successfully obtained by the solvothermal reaction of Eu3+ and heterofunctional ligand bpydbH2 (4,4′‐(4,4′‐bipyridine‐2,6‐diyl) dibenzoic acid), followed by terminal‐ligand exchange in a single‐crystal‐to‐single‐crystal transformation. As a result of treatments both before and after the metal–organic framework formation, accessible Lewis‐base sites and coordinated water molecules are successfully anchored onto the host material, and they act as signal transmission media for the recognition of analytes at the molecular level. This is the first reported sensor based on a metal–organic framework (MOF) with multi‐responsive optical sensing properties. It is capable of sensing small organic molecules and inorganic ions, and unprecedentedly it can discriminate among the homologues and isomers of aliphatic alcohols as well as detect highly explosive 2,4,6‐trinitrophenol (TNP) in water or in the vapor phase. This work highlights the practical application of luminescent MOFs as sensors, and it paves the way toward other multi‐responsive sensors by demonstrating the incorporation of various functional groups into a single framework.
A series of lanthanide metal‐organic frameworks (Ln‐MOFs) are synthesized through solvothermal conditions with 1,3‐bis(4‐carboxyphenyl)imidazolium (H2L). Owing to the lanthanide contraction effect, two different types of Ln‐MOFs, namely, {[Ln(L)2(OH)]·3H2O}n (Ln:Pr, Nd, Sm) and {[Ln(L)2(COO)(H2O)2]·H2O}n (Ln: Eu, Gd, Tb, Dy, Tm, Yb, Y), and their corresponding codoped Ln‐MOFs EuxTb1‐xL are obtained. With careful adjustment of the relative concentration of the lanthanide ions and the excitation wavelength, the color of the luminescence can be systematically modulated and white light emission can be further successfully achieved. Furthermore, by virtue of the temperature‐dependent luminescent behavior, Eu0.2Tb0.8L allows for the design of a thermometer with an excellent linear response to temperature over a wide range, from 40 to 300 K. This work highlights the practical applications of Ln‐MOFs for tailoring fluorescent color and even obtaining practical white light emission, and especially for sensing temperature as luminescent thermometers in a single framework by controlling in different ways.
Layered double hydroxides (LDHs) are promising cathode materials for supercapacitors because of the enhanced flow efficiency of ions in the interlayers. However, the limited active sites and monotonous metal species further hinder the improvement of the capacity performance. Herein, cobalt sulfide quantum dots (Co9S8‐QDs) are effectively created and embedded within the interlayer of metal‐organic‐frameworks‐derived ternary metal LDH nanosheets based on in situ selective vulcanization of Co on carbon fibers. The hybrid CF@NiCoZn‐LDH/Co9S8‐QD retains the lamellar structure of the ternary metal LDH very well, inheriting low transfer impedance of interlayer ions. Significantly, the selectively generated Co9S8‐QDs expose more abundant active sites, effectively improving the electrochemical properties, such as capacitive performance, electronic conductivity, and cycling stability. Due to the synergistic relationship, the hybrid material delivers an ultrahigh electrochemical capacity of 350.6 mAh g−1 (2504 F g−1) at 1 A g−1. Furthermore, hybrid supercapacitors fabricated with CF@NiCoZn‐LDH/Co9S8‐QD and carbon nanosheets modified by single‐walled carbon nanotubes display an outstanding energy density of 56.4 Wh kg−1 at a power density of 875 W kg−1, with an excellent capacity retention of 95.3% after 8000 charge–discharge cycles. Therefore, constructing hybrid electrode materials by in situ‐created QDs in multimetallic LDHs is promising.
Designing
metal–organic framework (MOF)-encapsulated hybrid
catalysts is considered as an effective way to realize catalytic selectivity
because of advantages related to the unique channels of MOF. Here,
a sodium polystyrenesulfonate (PSS)-induced, microwave-assisted route
was developed to controllably construct Pt/CeO2@MOF core@shell
hybrids. Using PSS as a modifying agent and followed by microwave
assistance, MOFs could be continuously grown in an oriented manner
on Pt/CeO2 nanospheres. The obtained Pt-CeO2@UIO-66-NH2 exhibited high conversion (99.3%) with high
selectivity (>99%) for selective hydrogenation of furfural to furfuryl
alcohol. It showed that the CeO2 would promote the catalytic
activity, whereas the size confinement effect of the UIO-66-NH2 channels can enhance the catalytic selectivity. This work
highlights a useful strategy toward the universal synthesis of highly
active, stable, and selective catalysts for further utilization.
Ginsenoside Rg1 is a major active ingredient of Panax notoginseng radix which has demonstrated a number of pharmacological actions including a cardioprotective effect in vivo. This study investigated the protective effect and mechanism of ginsenoside Rg1 in cardiomyocytes hypoxia/reoxygenation (H/R) model. Pretreatment with ginsenoside Rg1 (60-120 microM) reduced lactate dehydrogenase release and increased cell viability in a dose-dependent manner. Fluorescence analysis demonstrated ginsenoside Rg1 reduced intracellular ROS and suppressed the intracellular [Ca(2+)] level. Cell lysate detected an increase of T-SOD, CAT, and GSH levels. The myocardial protection of ginsenoside Rg1 during H/R is partially due to its antioxidative effect and intracellular calcium homeostasis.
Mercury(II) ions have emerged as a widespread environmental hazard in recent decades. Despite different kinds of detection methods reported to sense Hg(2+) , it still remains a challenging task to develop new sensing molecules to replenish the fluorescence-based apparatus for Hg(2+) detection. This communication demonstrates a novel fluorescent sensor using UiO-66-NH2 and a T-rich FAM-labeled ssDNA as a hybrid system to detect Hg(2+) sensitively and selectively. To the best of our knowledge, it has rarely been reported that a MOF is utilized as the biosensing platform for Hg(2+) assay.
The fabrication of ultrasmall and high‐content SnO2 nanocrystals anchored on doped graphene can endow SnO2 with superior electrochemical properties. Herein, an effective strategy, involving molecular engineering of a layer‐by‐layer assembly technique, is proposed to homogeneously anchor SnO2 nanocrystals on nitrogen/sulfur codoped graphene (NSGS), which serves as an advanced anode material in lithium/sodium‐ion batteries (LIBs/SIBs). Benefiting from novel design and specific structure, the optimized NSGS for LIBs displays high initial capacity (2123.9 mAh g−1 at 0.1 A g−1), long‐term cycling performance (only 0.8% loss after 500 cycles), and good rate capability (477.4 mAh g−1 at 5 A g−1). In addition, the optimized NSGS for SIBs also delivers high initial capacity (791.7 mAh g−1 at 0.1 A g−1) and high reversible capacity (180.2 mAh g−1 after 500 cycles at 0.5 A g−1). Meanwhile, based on the detailed analysis of phase transition and electrochemical reaction kinetics, the reaction mechanisms of NSGS in LIBs and SIBs as well as the distinction in LIBs/SIBs are clearly articulated. Notably, to further explore the practical application, Li/Na+ full cells are also assembled by coupling the optimized NSGS anode with LiCoO2 and Na3V2(PO4)3/C cathodes, respectively.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.