Electrochemiluminescent assay based on Co-MOF and TiO2 for determination of bisphenol A.

An electrochemiluminescence (ECL) sensor for determining bisphenol A (BPA) was prepared based on titanium dioxide (TiO2) and Co-MOF. TiO2 is a co-reaction promoter that amplifies the ECL signal in the Ru(bpy)32+-trinpropylamine (TPrA) system. When the electrode is modified with Co-MOF the ECL signal is significantly enhanced. This is because Co-MOF can not only be used as a co-reaction accelerator but also as a carrier to adsorb more luminescent substances. Possible mechanisms for amplifying the original signal through the synergistic action of the two substances are investigated. The ECL strength decreases with increasing concentrations of BPA, and the amount of BPA can be determined by the change in ECL signal strength (ΔI). Under optimal experimental conditions, the linear range of BPA was 2.0 × 10-10 to 2.0 × 10-5 M, with a determination limit of 6.7 × 10-11 M (3σ/m). The relative standard deviation (RSD) of the signal for ten consecutive measurements was 1.5%. The sensor can be used to detect BPA in bottled samples with recoveries of 96 to 105%.

Synthesis, Structure and Antibacterial Activity of Two Novel Coordination Polymers Based on N,N'-bis(4-carbozvlbenzvl)-4-aminotoluene and Heterocyclic Ligand against S. aureus.

As the use of antibiotics increases, the increasing resistance of bacteria is the main reason for the reduced efficiency of antibacterial drugs, making the research of new antibacterial materials become new hot spot. In this article, two novel coordination polymers (CPs), namely, [Cd2(L)2(bibp)2]n (1) and [Ni(L)(bib)]n (2), where H2L = N,N'-bis(4-carbozvlbenzvl)-4-aminotoluene, bibp = 4,4'-bis(imidazol-1-yl)biphenyl, and bib = 1,3-bis(1-imidazoly)benzene, have been synthesized under solvothermal and hydrothermal condition. Structural clarification was performed through infrared spectrum and single-crystal X-ray diffraction analysis, while thermal analysis and XRD technology were used for the performance assessment of compounds 1 and 2. In addition, antibacterial performance experiments showed that compounds 1 and 2 have certain selectivity in their antibacterial properties and have good antibacterial properties against S. aureus. As the concentration of the compound increases, the inhibitory effect gradually strengthens, and when the concentration of the compound reaches 500 µg/mL and 400 µg/mL, the concentration of the S. aureus solution no longer increases and has been completely inhibited.

Application of a Mixed-Ligand Metal-Organic Framework in Photocatalytic CO2 Reduction, Antibacterial Activity and Dye Adsorption.

In this paper, a known mixed-ligand MOF {[Co2(TZMB)2(1,4-bib)0.5(H2O)2]·(H2O)2}n (compound 1) was reproduced, and its potential application potential was explored. It was found that compound 1 had high photocatalytic activity for CO2 reduction. After 12 h of illumination, the formation rate of CO, which is the product of CO2 reduction by compound 1, reached 3012.5 µmol/g/h. At the same time, compound 1 has a good antibacterial effect on Staphylococcus aureus (S. aureus), Escherichia coli (E. coli) and Candida albicans (C. albicans), which has potential research value in the medical field. In addition, compound 1 can effectively remove Congo Red from aqueous solutions and achieve the separation of Congo red from mixed dye solutions.

LAZY3 plays a pivotal role in positive root gravitropism in Lotus japonicus.

LAZY1 family genes play important roles in both shoot and root gravitropism in plants. Here we report a Lotus japonicus mutant that displays negative gravitropic response in primary and lateral roots. Map-based cloning identified the mutant gene LAZY3 as a functional ortholog of the LAZY1 gene. Mutation of the LAZY3 gene reduced rootward polar auxin transport (PAT) in the primary root, which was also insensitive to the PAT inhibitor N-1-naphthylphthalamic acid. Moreover, immunolocalization of enhanced green fluorescent protein-tagged LAZY3 in L. japonicus exhibited polar localization of LAZY3 on the plasma membrane in root stele cells. We therefore suggest that the polar localization of LAZY3 in stele cells might be required for PAT in L. japonicus root. LAZY3 transcripts displayed asymmetric distribution at the root tip within hours of gravistimulation, while overexpression of LAZY3 under a constitutive promoter in lazy3 plants rescued the gravitropic response in roots. These data indicate that root gravitropism depends on the presence of LAZY3 but not on its asymmetric expression in root tips. Expression of other LAZY genes in a lazy3 background did not rescue the growth direction of roots, suggesting that the LAZY3 gene plays a distinct role in root gravitropism in L. japonicus.

Graphitic Carbon Nitride (g-C3N4) Nanosheets/Graphene Composites: In Situ Synthesis and Enhanced Photocatalytic Performance.

A facile In Situ growth method was presented here for the preparation of graphitic carbon nitride (g-C3N4)/graphene composites, in which the direct growth and deposition of g-C3N4 nanosheets from organic N and C sources on the graphene surfaces was achieved to form the 3D contacted structure. The resulting 3D architecture possessed multilevel porous structure and efficient g-C3N4/graphene interfaces, which facilitated the fast electron transfer at the interfaces. Photoluminescence spectra showed that the recombination of photogenerated electrons and holes in the g-C3N4/graphene composites was greatly inhibited by the introduction of graphene, indicating the more efficient separation of electrons and hole in the g-C3N4/graphene composites than in pure g-C3N4. The catalytic activity of g-C3N4/graphene composite photocatalyst was enhanced by over two fold compared to pure g-C3N4 for removal of Rhodamine B under simulated sun light irradiation. This work indicates that the metal-free g-C3N4/graphene composite photocatalyst is a promising nanomaterial for further applications in water treatment.

A Novel and Simple Method for the Synthesis of ß-SiC/SiO2 Coaxial Nanocables in a Large Area: Polycarbosilane Pyrolysis.

In the present work, ß-SiC/SiO2 coaxial nanocables are synthesized in a large area via direct pyrolysis of polymeric precursor method, in which, polycarbosilane acts the single raw material. The morphology, chemical composition and detailed microstructure of the nanocables are characterized. The core of nanocables are single crystalline ß-SiC nanowires with diameter of 30 - 60 nm grown along [111] direction. The uniform coating layer is amorphous SiO2 with thickness of 15 nm. Based on the pyrolysis process of polycarbosilane, the Vapor-Liquid-Solid growth mechanism is discussed. Furthermore, field emission measurements show the turn-on field and the threshold field are 3.2 V/µm and 6.5 V/µm, respectively. This study shows that ß-SiC/SiO2 coaxial nanocables are promising for field emission display device and other vacuum electronic devices.

Application of a Metal Cobalt Based on 4,6-Bis(imidazol-1-yl)isophthalicacid Metal-Organic -Framework Materials in Photocatalytic CO2 Reduction, Antibacterial, and Dye Adsorption.

In this paper, the reported MOF ([Co(bimip)(H2O)0.5]·0.5H2O) was employed in photocatalytic CO2 reduction, antibacterial, and dye adsorption experiments. The photocatalytic activity of the MOF for CO2 reduction was systematically investigated. The high average CO generation rate of 3421.59 µmol·g-1·h-1 after 12 h confirms the efficient photocatalytic CO2 reduction ability of the MOF. At the same time, the MOF can completely inhibit the growth of S. aureus and C. albicans within 24 h when its concentration reaches 400 µg/mL and 500 µg/mL, respectively. The MOF has an adsorption capacity for CR. The adsorption rate was 83.42% at 60 min, and the adsorption capacity of the MOF for CR reached 500.00 mg·g-1.

An Equivalent Substitute Strategy for Constructing 3D Ordered Porous Carbon Foams and Their Electromagnetic Attenuation Mechanism.

Three-dimensional (3D) ordered porous carbon is generally believed to be a promising electromagnetic wave (EMW) absorbing material. However, most research works targeted performance improvement of 3D ordered porous carbon, and the specific attenuation mechanism is still ambiguous. Therefore, in this work, a novel ultra-light egg-derived porous carbon foam (EDCF) structure has been successfully constructed by a simple carbonization combined with the silica microsphere template-etching process. Based on an equivalent substitute strategy, the influence of pore volume and specific surface area on the electromagnetic parameters and EMW absorption properties of the EDCF products was confirmed respectively by adjusting the addition content and diameter of silica microspheres. As a primary attenuation mode, the dielectric loss originates from the comprehensive effect of conduction loss and polarization loss in S-band and C band, and the value is dominated by polarization loss in X band and Ku band, which is obviously greater than that of conduction loss. Furthermore, in all samples, the largest effective absorption bandwidth of EDCF-3 is 7.12 GHz under the thickness of 2.13 mm with the filling content of approximately 5 wt%, covering the whole Ku band. Meanwhile, the EDCF-7 sample with optimized pore volume and specific surface area achieves minimum reflection loss (RLmin) of - 58.08 dB at 16.86 GHz while the thickness is 1.27 mm. The outstanding research results not only provide a novel insight into enhancement of EMW absorption properties but also clarify the dominant dissipation mechanism for the porous carbon-based absorber from the perspective of objective experiments.

Synergy Strategy of Electrical Conductivity Enhancement and Vacancy Introduction for Improving the Performance of VS4 Magnesium-Ion Battery Cathode.

The development of cathode materials with a high electric conductivity and a low polarization effect is crucial for enhancing the electrochemical properties of magnesium-ion batteries (MIBs). Herein, Mo doping and nitrogen-doped tubular graphene (N-TG) introduction are carried out for decorating VS4 (Mo-VS4/N-TG) via the one-step hydrothermal method as a freestanding cathode for MIBs. The results of characterizations and density functional theory (DFT) reveal that rich sulfur vacancies are induced by Mo doping, and N-TG as a high conductive skeleton material serves to disperse the active material and forms a tight connection, all of which collectively improved the electrical conductivity of electrode and increased the adsorption energy of Mg2+ (-6.341 eV). Furthermore, the fast reaction kinetics is also confirmed by the galvanostatic intermittent titration technique (GITT) and the pesudocapacitance-like contribution analysis. Benefiting from the synergistic effect of electrical conductivity enhancement and rich vacancy introduction, Mo-VS4/N-TG delivers a steady Mg2+ storage specific capacity of about 140 mAh g-1 at 50 mA g-1, outstanding cycle stability (80.6% capacity retention ratio after 1200 cycles under 500 mA g-1), and excellent rate capability (specific capacity reaches 77.1 mAh g-1 when the current density reaches 500 mA g-1). In addition, the reversible reaction process, intercalation mechanism, and structural stability during the Mg2+ insertion/extraction process are confirmed by a series of ex situ characterizations. This research provides a sustainable and scalable strategy to spur the development of MIBs.

Amorphous nickel sulfide nanoparticles anchored on N-doped graphene nanotubes with superior properties for high-performance supercapacitors and efficient oxygen evolution reaction.

The rational design of a novel material system with superior properties of energy storage and conversion is a significant work. In this paper, amorphous nickel sulfide nanoparticles anchored on N-doped graphene nanotubes (N-GNTs@NSNs) were firstly synthesized by a facile electrochemical-deposition method, which can serve as free-standing robust supercapacitor electrode materials and electrocatalysts. Stemming from the disordered structure of amorphous active materials and the synergy of novel N-GNT framework materials, the as-prepared N-GNT@NSN electrode unveils prominent capacitive behaviors, including a large specific capacity of 240 mA h g-1 (2160 F g-1), decent rate capability, and outstanding cycling stability (95.8% of capacity retention after 12 000 cycles). An asymmetric supercapacitor with N-GNTs@NSNs as the positive electrode and active carbon (AC) as the negative electrode is further assembled, which shows a maximum energy density of 49.5 W h kg-1 at a power density of 800 W kg-1 and robust stability (96.6% capacity retention after 12 000 cycles). Moreover, the electrode also possesses high activities in the oxygen evolution reaction (OER), namely it can attain a current density of 10 mA cm-2 at an overpotential of 284 mV in 1 M KOH. This finding is not only important for significantly enhancing the electrochemical performances of supercapacitor electrode materials and electrocatalysts, but also lays the solid foundation for their further industrial applications in energy storage and conversion systems.

SiO2/ZnO Composite Hollow Sub-Micron Fibers: Fabrication from Facile Single Capillary Electrospinning and Their Photoluminescence Properties.

In this work, SiO2/ZnO composite hollow sub-micron fibers were fabricated by a facile single capillary electrospinning technique followed by calcination, using tetraethyl orthosilicate (TEOS), polyvinylpyrrolidone (PVP) and ZnO nanoparticles as raw materials. The characterization results of the scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) spectra indicated that the asprepared composite hollow fibers consisted of amorphous SiO2 and hexagonal wurtzite ZnO. The products revealed uniform tubular structure with outer diameters of 400-500 nm and wall thickness of 50-60 nm. The gases generated and the directional escaped mechanism was proposed to illustrate the formation of SiO2/ZnO composite hollow sub-micron fibers. Furthermore, a broad blue emission band was observed in the photoluminescence (PL) of SiO2/ZnO composite hollow sub-micron fibers, exhibiting great potential applications as blue light-emitting candidate materials.