Latest ArticlesBy considering the exceptional properties of supramolecular, noble metals (NM) and magnetic nanoparticles (NPs), we successfully synthesized a novel magnetic, metals and supramolecular composite. Briefly, the Fe3O4@SiO2 core-shell spheres were first modified with gold (Au) and palladium (Pd) NPs and then with mono-6-thio-β-cyclodextrin (SH-β-CD). The synthesized Fe3O4@SiO2-Au-Pd@SH-β-CD nanocomposite shows a good magnetic response (42.3 emu/g). The nanocomposite showed good performance for the reductive degradation of rhodamine B (RhB) and 4-nitrophenol (4-NP). The calculated rate constant (k) values for the reduction of 4-NP and RhB were 0.062± 0.02 s−1 and 0.027± 0.01 s−1, respectively. The high catalytical performance was supposed to be due to the host-guest interaction of β-CD and also due to the NM synergic effect. The nanocomposite structural and chemical morphology was investigated by various spectroscopic techniques. Furthermore, the catalyst was recycled six times and it maintains morphology, chemical nature, and high magnetic behavior, as demonstrated by FTIR and TEM analysis of the recycled catalyst. These results demonstrate a very efficient, cost-effective, and recyclable catalyst in the field of catalysis technology development.
1,4-Enyne units are ubiquitous skeletons in biologically active molecules and natural products. Especially, they represent versatile building blocks for abundant downstream derivatizations via controllable modifications of both alkene and alkyne units independently. Recently, great efforts have been made to establish efficient protocols to achieve optically active 1,4-enynes. Considering the enormous application potential of enantioenriched 1,4-enyne units but no related review on this topic has been described, here we aim to provide a comprehensive summary on the catalytic methods established for enantioselective constructions of these intriguing skeletons. According to the reaction types, this review is divided into five parts, including asymmetric allylic substitution, asymmetric propargylic substitution, asymmetric alkynylallylic substitution, asymmetric hydroalkynylation and asymmetric 1,2-addition of alkynes to conjugated imines or ketones.
Nucleic acid detection (NAD) based on real-time polymerase chain reaction (real-time PCR) is gold standard for infectious disease detection. Magnetic nanoparticles (MNPs) are widely used for nucleic acid extraction (NAE) because of their excellent properties. Microfluidic technology makes automated NAD possible. However, most of the NAD microfluidic chips are too complex to be applied to point-of-care (POC) testing. In this paper, a simple-structure cartridge was developed for POC detection of infectious diseases. This self-contained cartridge can be divided into a magnetic-controlled NAE part, a valve-piston combined fluidic control part and a PCR chip, which is able to extract nucleic acid from up to 500 µL of liquid samples by MNPs and finish the detection process from “sample in” to “answer out” automatically. Performance tests of the cartridges show that it met the demands of automated NAD. Results of on-cartridge detection of hepatitis B virus (HBV) demonstrated that this system has good uniformity and no cross-contamination between different cartridges, and the limit of detection (LOD) of this system for HBV in serum is 50 IU/mL. Multiplex detections of severe acute respiratory syndrome coronaviruses 2 (SARS-CoV-2) with a concentration of 500 copies/mL were carried out on the system and 100% positive detection rate was achieved.
Ammonium vanadate compounds featuring large capacity, superior rate capability and light weight are regarded as promising cathode materials for aqueous zinc ion batteries (AZIBs). However, the controllable synthesis of desired ammonium vanadates remains a challenge. Herein, various ammonium vanadate compounds were successfully prepared by taking advantage of ethylene glycol (EG) regulated polyol-reduction strategy and solvent effect via hydrothermal reaction. The morphology and crystalline phase of resultant products show an evolution from dendritic (NH4)2V6O16 to rod-like NH4V4O10 and finally to lamellar (NH4)2V4O9 as increasing the amount of EG. Specifically, the NH4V4O10 product exhibits a high initial capacity of 427.5 mAh/g at 0.1 A/g and stable cycling with a capacity retention of 90.4% after 5000 cycles at 10 A/g. The relatively excellent electrochemical performances of NH4V4O10 can be ascribed to the stable open-framework layered structure, favorable (001) interplanar spacing, and peculiar rod-like morphology, which are beneficial to the highly reversible Zn2+ storage behaviors. This work offers a unique way for the rational design of high-performance cathode materials for AZIBs.
The organic carbon source coating LiFexMn1-xPO4 suffers from the problem of non-uniform carbon cladding. Too thick carbon cladding layer instead hinders the de-embedding of lithium ions. In this paper, we choose cornstalk as the carbon source, then LiFe0.5Mn0.5PO4@cornstalk-C (LFMP@C-C) with 3D anchoring structure is prepared by the solvothermal method. The results show that the LFMP with cornstalk as the carbon source has better performance compared to the sucrose-coated LFMP material (LFMP@C). The discharge capacity of LFMP@C-C is 116 mAh/g for the first cycle at 1 C and the capacity retention rate is 94.0% after 500 cycles, and the discharge capacity of LFMP@C-C is more than 17.17% higher than that of LFMP@C.
Electrochemical oxidation of aqueous tris(1,3-dichloro-2-propyl) phosphate (TDCPP) by using Ti/SnO2-Sb/La-PbO2 as anode was investigated for the first time, and the degradation mechanisms and toxicity changes of the degradation intermediates were further determined. Results suggested that electrochemical degradation of TDCPP followed pseudo-first-order kinetics, and the reaction rate constant (k) was 0.0332 min−1 at the applied current density of 10 mA/cm2 and Na2SO4 concentration of 10 mmol/L. There was better TDCPP degradation performance at higher current density. Free hydroxy radical (·OH) was proved to play dominant role in TDCPP oxidation via quenching experiment, with a relative contribution rate of 60.1%. A total of five intermediates (M1, C6H11Cl4O4P; M2, C3H7Cl2O4P; M3, C9H16Cl5O5P; M4, C9H14Cl5O6P; M5, C6H10Cl3O6P) were identified, and the intermediates were further degraded prolonging with the reaction time. Flow cytometer results suggested that the toxicity of TDCPP and degradation intermediates significantly reduced, and the detoxification efficiency was achieved at 78.1% at 180 min. ECOSAR predictive model was used to assess the relative toxicity of TDCPP and the degradation intermediates. The EC50 to green algae was 3.59 mg/L for TDCPP, and the values raised to 84, 574, 54.6, 391, and 8920 mg/L for M1, M2, M3, M4, and M5, respectively, indicating that the degradation intermediates are less toxic or not toxic. Electrochemical advanced oxidation process is a valid technology to degrade TDCPP and pose a good detoxification effect.
Spatial configuration has a significant effect on chemical self-assembly. However, the importance of spatial configuration in supramolecular adhesive materials has been frequently ignored. In this study, the effects of the spatial configuration on cohesion and adhesion were investigated. Owing to the diversities of the chemical structures and assembly patterns, 1,2-disubstituted cyclohexane derivatives were used in this combined experimental and theoretical investigation. The self-sorting assembly of enantiopure isomers improved cohesion but had a negative effect on adhesion. In contrast, racemic mixtures displayed stronger adhesion effects. Moreover, it was proven that the cis-configuration was more favorable for supramolecular adhesion than the trans-counterpart. In addition, the influence of the spatial configuration of 1,2-disubstituted cyclohexane derivatives could be effectively mitigated by hydrogen bond donors or acceptors. The addition of natural acids yielded three-dimensional polymeric networks, in which the spatial configuration was not the decisive factor for supramolecular adhesion.
Anthropogenic carbon dioxide (CO2) emission from the combustion of fossil fuels aggravates the global greenhouse effect. The implementation of CO2 capture and transformation technologies have recently received great attention for providing a pathway in dealing with global climate change. Among these technologies, electrochemical CO2 capture technology has attracted wide attention because of its environmental friendliness and flexible operating processes. Bipolar membranes (BPMs) are considered as one of the key components in electrochemical devices, especially for electrochemical CO2 reduction and electrodialysis devices. BPMs create an alkaline environment for CO2 capture and a stable pH environment for electrocatalysis on a single electrode. The key to CO2 capture in these devices is to understand the water dissociation mechanism occurring in BPMs, which could be used for optimizing the operating conditions for CO2 capture and transformation. In this paper, the references and technologies of electrochemical CO2 capture based on BPMs are reviewed in detail, thus the challenges and opportunities are also discussed for the development of more efficient, sustainable and practical CO2 capture and transformation based on BPMs.
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