Nano

In this study, positively charged polystyrene-co-poly (ar-vinylbenzyl) trimethylammonium nanoparticles loading with Aggregation Induced Emission (AIE) fluorescent molecule sulfonated 9,10-distyrylanthracene derivatives (SDSA) by coulomb force denoted as SDSA/PS-co-PVBTAC have been prepared. The size, size distribution and morphology of nanoparticles have been tested by Dynamic light scattering (DLS) and Scanning electron microscope (SEM). The synthesized nanoparticles possess uniform size, good monodispersity and low biological toxicity. The AIE-type SDSA/PS-co-PVBTAC showed good fluorescence stability at pH from 3 to 10. It has been proved that the biological macromolecules including Bovine Serum Albumin (BSA), DNA and RNA can amplify the cell imaging signals. Moreover, the AIE-type nanoparticles have been shown to perform fluorescent imaging of various cells. It suggests that the prepared SDSA/PS-co-PVBTAC can be used as a new biological probe in the field of cell imaging and detection, as well as expanding the application of AIE fluorescent molecules in biosensing field.

Carbon encapsulated transition metal catalysts receive extensive attention in electrochemical catalytic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) due to the unique structure and highly adjustable electronic configuration. Herein, we synthesized 3D porous Active-N-rich graphene-like carbon layer-encapsulated Fe/Fe₃C (Fe@NCG) via pyrolysis of a mixture of solvent-free assembled Fe-chitosan chelates and additional small molecule nitrogen source urea, wherein space-confinement effect of chelates suppressed agglomeration of ${\text{Fe}}^{3+}$ ions and small molecule nitrogen source facilitated regulation of N configurations. The optimized catalyst Fe@NCG shows remarkable ORR/OER bifunctional catalytic activity with a half-wave potential of 0.86 V for ORR and a moderate potential difference of 0.85 V in alkaline medium. Comparative studies revealed that Active-N-rich carbon layer and inner well-dispersed Fe/Fe₃C nanoparticles and the favorable interface structures between them were responsible for high catalytic activity. Excitingly, the assembled zinc-air battery with Fe@NCG catalysts exhibits a high open-circuit potential (1.45 V), extremely high peak power density (204.50${\text{mW/cm}}^2)$ and energy density (814.70Wh${}^{\text{kg}}$) as well as robust charge–discharge durability, surpassing those of noble metal catalyst. This proposed simple and universal strategy can also be extended to synthesize carbon encapsulated other transition metal electrocatalysts.

We constructed a multifunctional (Fe₃O₄/nGO)@mSiO₂/GQDs drug carrier for loading and microwave-controlled release of an etoposide (VP16) as the anticancer drug. This nanocomposite consisted of magnetic core Fe₃O₄, microwave-absorbing nanographene oxide (nGO), fluorescent graphene quantum dots (GQDs) and intermediate barrier layer (mesoporous silica). It has a large surface area of 359.8m²/g, excellent fluorescence emission and ample magnetic performance of 36.00emu/g. After microwave irradiation for 140 s, the temperature of (Fe₃O₄/nGO)@mSiO₂/GQDs nanoparticles rapidly went up to 90^∘C. The loading rate of VP16 was as high as 68%, the release rate reached 87% within 280min under microwave irradiation. Therefore, the functionalized (Fe₃O₄/nGO)@mSiO₂/GQDs nanoparticles will have potential application for clinical treatment as drug delivery system.

Carbon-coated nickel oxide nanoparticles (NiO@C) were synthesized by near-critical hydrothermal method using starch and nickel nitrate as precursors. Also,carbon-coated Ni nanoparticles (Ni@C) were obtained by annealing NiO@C nanoparticles in hydrogen atmosphere. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy(TEM), Raman spectroscopy, simultaneous thermal analysis (STA) and physical property measurement system (PPMS). The average sizes of the NiO and Ni nanoparticles were 18nm and 15nm according to the XRD analysis, respectively. Raman spectroscopy and thermogravimetric analysis demonstrated that the carbon shells of NiO@C and Ni@C nanoparticles were composed of amorphous and partially graphitized carbon. The formation mechanism of NiO@C and Ni@C nanoparticles was briefly discussed. The Ni@C nanoparticles have enhanced coercive force than bulk nickel, and their coercive force has shown a linear dependence on the square root of temperature.

In this study, silver sulfadiazine (SSD) loaded Poly ($\epsilon$-caprolactone)/Poly (ethylene oxide) (PCL/PEO) nanofiber patches were prepared via electrospinning method for topical drug delivery applications. SSD was loaded for the first time into PCL/PEO nanofibers. Nanofiber patches were characterized by Attenuated Total Reflectance Infrared Spectroscopy (FTIR-ATR) to check the presence of chemical bonding between SSD and polymer matrix. The surface morphology of the nanofibers was observed by Scanning Electron Microscopy (SEM). SEM images showed that uniform and smooth composite nanofibers were obtained. The diameter of the nanofibers decreased with the addition of SSD. X-Ray Diffraction (XRD) analysis was carried out to examine the crystallinity of composite nanofiber patches. Energy dispersive spectroscopy (EDS) analysis was performed to confirm Ag and S contents in the SSD loaded composite nanofibers and EDS Mapping was used to show the homogeneous distribution of SSD in the fiber structure. In order to investigate the release and solubility properties of SSD, an unused buffer solution; Water/Propylene Glycol/Phosphoric Acid (82:16:2) was prepared. The release of SSD was performed in this buffer and the release amount of SSD was calculated by UV-Visible Spectrophotometer. Thereby, SSD containing PCL/PEO composite nanofiber carriers were electrospun to achieve the enhancement in solubility, effective drug release and efficient drug loading of SSD. All experimental studies demonstrated that SSD loaded PCL/PEO composite nanofibers have great potential to be used in topical drug delivery applications.

Phenolic compounds, especially 4-nitrophenol (4-NP), and chromium (VI) are highly toxic environmental pollutants. Thus, it is significantly important to establish a rapid and sensitive sensor for 4-NP and Cr(VI) monitoring in environment. In this paper, a novel approach has been adopted where E. coli-derived CDs (CDs-WT) prepared by one step hydrothermal method previously and sensitized by ampicillin (turn-on) were used as fluorescence nanoprobe (CDs-WT-Amp) for 4-NP and Cr(VI) determination based on the inner filter effect quenching mechanism (turn-off). Then, the quenching fluorescence was reversed by addition of ampicillin (turn-on). The linear ranges of 4-NP and Cr(VI) detection were 0–50$\mu$M and 0–25$\mu$M, with the limits of detection 88.89nM and 64.75nM, respectively. The “turn-on-on-off-on” fluorescent nanosensor system was successfully used to determine Cr(VI) and 4-NP in water with satisfactory results. It shows that the “turn-on-off-on” nanoprobe has great promising potential for application to environmental pollutant detection.

Photodynamic therapy (PDT) holds great promise as an effective approach to kill multidrug resistant (MDR) bacteria. In this study, KMnF3:Yb,Er upconversion nanoparticles (UCNPs) were prepared and modified with zinc phthalocyanine (ZnPc), a photosensitizer with a major absorption band at 670nm. ZnPc absorbs the emission at 660nm of the UCNPs producing reactive oxygen species (ROS) which kill the surrounding bacteria. The UCNPs were also modified with Tween to make them water-soluble and biocompatible, and oleylamine to provide positive charges to shorten the distance from bacteria. Detection of singlet oxygen production, bacteria viability test and confocal imaging were performed, respectively. The as-prepared system (UCNPs@ZnPc@Tween) shows enhanced efficiency of PDT against both Gram-negative and Gram-positive bacteria.

Silicon is widely studied as a high-capacity lithium-ion battery anode. However, the pulverization of silicon caused by a large volume expansion during lithiation impedes it from being used as a next generation anode for lithium-ion batteries. To overcome this drawback, we synthesized ultrathin silicon nanowires. These nanowires are 1D silicon nanostructures fabricated by a new bi-metal-assisted chemical etching process. We compared the lithium-ion battery properties of silicon nanowires with different average diameters of 100nm, 30nm and 10nm and found that the 30nm ultrathin silicon nanowire anode has the most stable properties for use in lithium-ion batteries. The above anode demonstrates a discharge capacity of 1066.0mAh/g at a current density of 300mA/g when based on the mass of active materials; furthermore, the ultrathin silicon nanowire with average diameter of 30nm anode retains 87.5% of its capacity after the 50th cycle, which is the best among the three silicon nanowire anodes. The 30nm ultrathin silicon nanowire anode has a more proper average diameter and more efficient content of SiO_x. The above prevents the 30nm ultrathin silicon nanowires from pulverization and broken during cycling, and helps the 30nm ultrathin silicon nanowires anode to have a stable SEI layer, which contributes to its high stability.

Water electrolysis is of vital importance to store renewable energy and the development of efficient, inexpensive and stable electrocatalysts for oxygen evolution reaction (OER) is essential, which requires much more understanding of the structural and the element classification. Here, a series of ${\text{LaNi}}_{0.8}$Fe_x${\text{Cu}}_{0.2-x}$${\text{O}}_{3-\delta }$ perovskites have been assessed as potential noble-metal-free OER electrocatalysts prepared by sol–gel method. Moreover, the functional role of Cu and Fe amount on the B-site of perovskites for OER electrocatalytic performance was evaluated. ${\text{LaNi}}_{0.8}$${\text{Fe}}_{0.2}$${\text{O}}_{3-\delta }$ materials exhibited the highest intrinsic activities in 0.1M KOH for OER with an onset potential of 1.56V, a Tafel slope of 76mV${\text{dec}}^{-1}$, slightly lower than that of benchmark perovskite-type electrocatalyst ${\text{Ba}}_{0.5}$${\text{Sr}}_{0.5}$C${\text{O}}_{0.8}$${\text{Fe}}_{0.2}$O₃ (BSCF). The above results demonstrate that Cu element in the B-site of perovskites had little effect on the OER performance, and ${\text{LaNi}}_{0.8}$${\text{Fe}}_{0.2}$${\text{O}}_{3-\delta }$ is a potential alternative electrocatalyst for OER application.

Friction between filler/filler and filler/matrix in rubber composites is the main factor affecting the heat build-up. In this study, we used dodecanol and silane coupling agent KH-592 to co-modify silica to prepare silica/natural rubber (NR) composites. When dodecanol and KH-592 are grafted onto the surface of silica at the same time, dodecanol can also shield part of the hydroxyl groups by its molecular chain length, which further improves the dispersibility of silica particles. The silane coupling agent KH-592 can form a bridge structure between the silica and the NR matrix under the action of a mercapto group, and improve the interaction between the filler and the matrix. By controlling the use ratio of dodecanol and KH-592, the dispersion of the filler and the interaction between the filler and the matrix can be adjusted. Thereby, the friction between the filler/filler and the filler/matrix is reduced, and a low heat build-up rubber composite material is prepared. Through co-modification, we prepared a series of low-heat build-up silica/NR composites, where the minimum heat generation reached 13^∘C. The co-modified silica/NR composite material not only meets the requirements of green tires, but also has low heat build-up characteristics, providing a new strategy for preparing green and energy-saving tires.

In this study, nitrogen-deficient graphitic carbon nitride (M-LS-g-C₃N₄) with a mesoporous structure and a large specific surface area was obtained by calcination after melt pretreatment using urea as a precursor. X-ray diffraction (XRD), transmission electron microscopy (TEM), N₂ adsorption, X-ray photoelectron spectroscopy (XPS), UV-Vis, ESR and photoluminescence (PL) were used to characterize the structure, morphology and optical performance of the samples. The TEM results showed the formation of a mesoporous structure on the 0.1M-LS-g-C₃N₄ surface. The porous structure led to an increase in the specific surface area from 41.5m²/g to 124.3m²/g. The UV-Vis results showed that nitrogen vacancies generated during the modification process reduced the band gap of g-C₃N₄ and improved the visible light absorption. The PL spectra showed that the nitrogen defects promoted the separation of photogenerated electron–hole pairs. In the visible light degradation of methyl orange (MO), the reaction rate constant of 0.1M-LS-g-C₃N₄ reached 0.0086${\text{min}}^{-1}$, which was 5.05 times that of pure g-C₃N₄. Superoxide radicals and photogenerated holes were found to be the main active species in the reaction system. This study provides an efficient, green and convenient means of preparing graphitic carbon nitride with a large specific surface area.

A novel and economical one-step liquid phase route combining the liquid phase reaction with rotary evaporation is successfully adopted to prepare LiFePO₄@C composite materials using iron phosphate dihydrate as iron source and phosphorus source. High temperature sintering was used to complete carbonization and control the size of precursor particles. X-ray diffraction (XRD) shows that all diffraction peaks are consistent of the standard pattern of FePO₄ 2H₂O and orthorhombic LiFePO₄. The structural characterization and micro-morphology of FePO₄ 2H₂O and as-prepared LiFePO₄@C are performed by the scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. The FePO₄ 2H₂O has the morphology of nano-flake particles with good dispersion. After carbon coating, LiFePO₄@C composite with mean carbon thickness of about 3nm exhibits a high discharge capacity of $160.7031\mathrm{\text{mAh}}\cdot {\mathrm{\text{g}}}^{-1}$ at 0.2C and $99.42616\mathrm{\text{mAh}}\cdot {\mathrm{\text{g}}}^{-1}$ at 10C. This method provides a simple, economic and environmentally friendly way to prepare LiFePO₄@C cathode material for lithium-ion battery.

Generation of hydrogen by sodium borohydride solution had attracted lots of attention. A serial of nanosized NiB catalysts were prepared using the chemical reduction method through introducing AlCl₃ into the preparation. Catalytic performance of NiB catalysts were investigated in the hydrolysis of alkaline NaBH₄ solution. The catalysts were characterized by X-ray diffraction (XRD), N₂ adsorption, Transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The results showed that NiB catalysts possessed amorphous alloy structure, and the particle size could be adjusted by the AlCl₃ amount. Catalytic performance showed that NiB catalyst with smaller particle size had much higher activity. The NiB catalyst also displayed high stability, the catalytic activity could retain about 84% of its initial value after four cycles.

A series of metal oxide nanocomposites have been successfully synthesized by electrospinning technology. The obtained nanocomposites (Cu₂O-Mn₃O₄-NiO) are an ordered arrangement of metal oxide particles (10nm), with the shape like bead chain. The acquired Cu₂O-Mn₃O₄-NiO ternary nanocomposites were used as electrode materials to manufacture a supercapacitor. Electrochemical tests showed that the synthesis of nanocomposites made of electrode materials had good electrochemical performance in 6mol/L KOH electrolyte. The results showed that at a scan rate of 5mV/s, the specific capacitance of Cu₂O-Mn₃O₄-NiO had a larger specific capacitance of 1306F/g than NiO, Cu₂O-NiO and Mn₃O₄-NiO. The excellent electrochemical performance showed that the electrostatic spinning method is an effective technology for developing nanocomposites for energy storage devices.