Nano

Ag-modified TiO₂ on activated carbon fibers (ACF) was synthesized and successfully used for the photocatalytic degradation of organic pollutants in this work. The physical properties of the materials were characterized using various methods such as X-ray diffraction, scanning electron microscope, Brunauer–Emmett–Teller, Fourier transform infrared, UV–Vis, electrochemical impedance spectroscopy and reusability tests. Besides, the effects of reaction parameters on photodegradation such as silver loading, light source, organic pollutant species and initial pollutant concentration were investigated. The results showed that Ag significantly increased the number of surface adsorption sites, improved the electron transmission rate and suppressed the complexation of e⁻ and h${}^{+}$. Under visible light, 1.5-Ag-TiO₂/ACF $[n(\mathrm{\text{Ag}}:{\mathrm{\text{TiO}}}_2)=1.5]$ revealed the best catalytic activity and reusability for dye removal and toluene adsorption. Based on the experimental results, a possible photocatalytic mechanism of Ag-TiO₂/ACF was proposed. This study will provide a theoretical basis for the application of Ag-TiO₂/ACF photocatalyst in the field of organic pollutants treatment.

This paper reports the design of a photoelectrochemical (PEC) sensing method for detecting levofloxacin (LEVX) in tablets. In this paper, a three-dimensional plasma Bi/BiPO₄/BiOI heterojunction was fabricated by a two-step method, in which Bi-metal and BiPO₄ were fixed on the surface of BiOI with beads. The composites were characterized by a variety of analytical methods. Bi/BiPO₄/BiOI-5% showed better photocatalytic activity than BiPO₄/BiOI. Indium tin oxide (ITO) modified with the Bi/BiPO₄/BiOI-5% composites was used to determine LEVX and achieved linear detection ranges of 0.2–2 $\mu$M and 2–7 $\mu$M. These composites present alternative materials for the analysis of antibiotics.

Lead halide perovskite is an attractive candidate for fabricating low-cost one-photon and two-photon-pumped lasers. However, the presence of vast trap sites and the leakage of electric fields limit the efficient amplified spontaneous emission (ASE) performances. Herein, we show that incorporating an insulating polymethylmethacrylate layer with a proper thickness onto perovskite films can play an important role in not only reducing both one-photon and two-photon ASE thresholds but also improving the light exposure stability remarkably. By means of spectroscopic investigation and optical simulation, the enhancement was ascribed to the trap passivation and electric field restraint and improved light outcoupling due to the dielectric confinement by the formation of symmetric waveguides structure. This work indicates the possibility of simple and effective approaches to realize efficient ASE and lasing.

In this study, we used a four-ball friction and wear testing machine to test the tribological properties of [HPy]BF₄ ionic liquids (ILs), low-layer graphene (G), and IL and G compounds (IL/G) as lubricant additives at variousconcentrations, loads, and speeds. The morphology of the wear scar was characterized by a white-light interferometer and a scanning electron microscope (SEM). The results showed that the optimal concentrations of IL and G were 0.10wt.% and 0.05wt.%, respectively. When the IL concentration was 0.10wt.%, the friction coefficient and the wear scar diameter (WSD) reduced by approximately 18% and 8%, respectively, compared to the base oil. When the concentration of G was 0.05wt.%, the friction coefficient and WSD reduced by approximately 23% and 12%, respectively, compared to the base oil. After adding the optimal concentration of the IL/G composite additive under the same test conditions, the average friction coefficient of the steel ball reduced by approximately 30%, and the average WSD reduced by approximately 18%. IL/G nanoadditives could be easily attached to the pit area on the friction surface of the steel ball, which made the contact surface of the friction pair smoother and the area of the oil film bearing the load larger, compared to those using the base oil. These two combined phenomena promoted synergistic antifriction and antiwear effects, which significantly improved the frictional performance of the base oil.

In the quantum system of nanolayer (NL) on silicon, the bandgap energy obviously increases with the decrease of NL thickness, where the quantum confinement (QC) effect plays the main role as the thickness of Si NL changes along with (100), (110) and (111) directions, respectively. And the simulation result demonstrated that the direct bandgap can be obtained as the NL with (001) direction is thinner than 10 nm on Si surface. However, it is discovered in the simulated calculation that the QC effect disappears as the NL thickness arrives at the size of the monoatomic layer, in which its bandgap sharply decreases, where the abrupt change effect in bandgap energy occurs near-ideal 2D-layer. In the experiment, we fabricated the Si NL structure by using electron beam irradiation and laser deposition methods, in which a novel way was used to control the NL thickness by modulating irradiation time of the electron beam. The new effect should have a good application on a photonic-electronic chip of silicon.

The lack of targeting selection to lysosome limits the application of graphene quantum dots (GQDs) in the diagnosis and treatment of lysosome-related disease. In this study, we developed a facile, environmentally friendly and large-scale method to prepare $N$-aminomorpholine (Am)-modified GQDs (Am-GQDs) via a simple hydrothermal method. The physicochemical, optical, biocompatible and targeted imaging properties were evaluated systematically. The results indicated that the synthesized Am-GQDs had a uniform size distribution and the size was around 2nm. In addition, the synthesized Am-GQDs had excellent optical properties, fluorescent stability, and good biocompatibility. More importantly, they can selectively target and image lysosome in a relatively short coculture time with cells, demonstrating their application potential in the diagnosis and treatment of lysosomal-related diseases.

Doping Ag-enhanced and glutathione-stabilized Au nanoclusters (GSH–Ag/AuNCs) were prepared by the one-step ultraviolet radiation combined with microwave heating method. The effects of the molar ratio of Au–Ag and different types of energy suppliers on the fluorescent performance of GSH–Ag/AuNCs were studied in detail. After that, a new ratio fluorescent probe (RF-probe) based on the mixing of GSH–Ag/AuNCs with carbon dots (CDs) was designed for sensitive and selective determination of copper gluconate (CG) and cupric sulfate (CS). For the CDs–GSH–Ag/AuNCs RF-probe, the fluorescence (FL) of CDs (at 440nm) and that of alloy nanoclusters (NCs) (at 605nm) were, respectively, unaffected and strongly quenched in the presence of CG/CS at ${\lambda }_{\mathrm{\text{ex}}}=370$nm coming from the dynamic quenching process. Corresponding linear ranges and limit of detection (LOD) of the RF-probe for the CG/CS assay were estimated to be 0.17–6.20/0.17–5.62$\mu$mol/L and 16.80/15.95nmol/L, respectively. Furthermore, the proposed RF-probe was successfully used for the assays of CG in CG tablets and CG additive, and CS in infant formula and CS additive, respectively.

To develop wide bandgap materials for solar cells and other optoelectronic devices, undoped hydrogenated silicon oxide (SiO_x:H) thin films are prepared by conventional radio frequency plasma enhanced chemical vapor deposition (RF PECVD) method. The variation of carbon dioxide dilution ($Y_c$) on optoelectronic and structural properties are studied thoroughly by keeping silane and hydrogen gas flow fixed. Surface morphology of the SiO_x:H films have been studied by Field Emission Scanning Electron Microscopy (FESEM) and Atomic Force Microscopy (AFM). Distinct silicon nanocrystallites of average diameter $\sim$ 3–6nm embedded uniformly in amorphous SiO_x network have been observed in high resolution Transmission Electron Microscopy (HRTEM). From Fourier Transform Infrared spectra (FTIR), it is observed that oxygen content ($C_o$) increases initially with $Y_c$ and afterwards it decreases. Strong room temperature photoluminescence (PL) peak is obtained for the as-deposited films having lower oxygen content ($C_o$). The origin of room temperature PL spectra and its correlation with $C_o$ can be explained by quantum confinement effect (QCE) theory.

In this paper, a new type of ultrathin sulfonated mesoporous silica film (SMSF) with well-ordered perpendicular mesochannels was in-situ synthesized by Stöber approach and co-condensation method. The mesostructure of the synthesized SMSF was characterized. The results of small-angle XRD, high-resolution TEM, and cyclic voltammetry (CV) exhibited that, after loading of MPTMS, SMSF had an ordered mesostructure with a perpendicular orientation and open ends. SEM showed that SMSF could be entirely transferred and easily handled. FT-IR presented that sulfonic groups were successfully added to the surface of the nanochannels of silica film. Compared with mesoporous silica film (MSF) and commercial cation exchange membrane (CEM), SMSF had the highest permselectivity. The permselectivity of SMSF was not lined with the loading of the sulfonic groups (–SO₃H). The highest permselectivity of SMSF to Na${}^{+}$ was 94% when the loading of MPTMS was 5.98% (wt.%). SMSF is a promising material in the application of salinity gradient energy harvest.

Since the inception of research on hollow silica, the use of hollow nanosilica (HNS) as additives in barrier materials has not been reported. In this study, we evaluated the capacity of HNS as an additive in modified polypropylene (MPP). According to X-ray diffraction (XRD), the crystallinity, tensile strength, and thermal stability of MPP/HNS nanocomposite containing 0.1phr HNS approached maximum values. Moreover, the nanocomposite had the best performance in terms of water vapor barrier and oxygen resistance. The reasons for the improvement in barrier performance were discussed. Scanning electron microscopy revealed that HNS at a low content dispersed well in MPP. In conclusion, the synthesized HNS can be used as an additive in barrier materials, and it would have potential applications in the fields of food packaging films and storage containers or materials.

As a new method of calculating materials, molecular dynamics simulation can effectively reproduce the mechanical behavior of materials at the atomic level. In this paper, through the construction of the AZ31 magnesium alloy model, the uniaxial compression deformation of magnesium alloy at different temperatures and strain rate is simulated by molecular dynamics method, the mechanical properties and microstructure changes of magnesium alloy are analyzed, the phase transformation mechanism of magnesium alloy under uniaxial compression is revealed, and the effects of temperature and strain rate on the phase transformation of magnesium alloy are explored at the nanometer scale. It provides a theoretical basis and necessary basic knowledge for the design and development of Mg-based nanostructured alloys with excellent mechanical properties.

Nanosized TiO₂ has been actively developed as a low-cost and environment-friendly anode material for lithium-ion batteries (LIBs), but its poor electronic conductivity seriously restricts its practical applications. This drawback is addressed in this work by the fabrication of one-dimensional mesoporous graphene@Ag@TiO₂ composite nanofibers as anode materials for high-performance LIBs. The materials were prepared via electrospinning combined with annealing treatment, and the effects of graphene addition on the microstructure and electrochemical performance of the resulting mesoporous graphene@Ag@TiO₂ nanofibers were investigated in detail. Ag@TiO₂ nanofibers with the optimal amount of graphene displayed a maximum initial discharge capacity of $490.5\mathrm{\text{mAh}}\cdot {\mathrm{\text{g}}}^{-1}$ at $100\mathrm{\text{mA}}\cdot {\mathrm{\text{g}}}^{-1}$ and retained a discharge capacity of $209.1\mathrm{\text{mAh}}\cdot {\mathrm{\text{g}}}^{-1}$ at $100\mathrm{\text{mA}}\cdot {\mathrm{\text{g}}}^{-1}$ after 100 cycles. These results reflect the excellent cycling stability of the material. The average specific discharge capacity of the nanofibers ($97.6\mathrm{\text{mAh}}\cdot {\mathrm{\text{g}}}^{-1}$ at $1000\mathrm{\text{mA}}\cdot {\mathrm{\text{g}}}^{-1})$ was two-fold higher than that of samples without graphene, and their discharge capacity returned to $253.8\mathrm{\text{mA}}\cdot {\mathrm{\text{g}}}^{-1}$ (approximately $96.2\mathrm{\text{mA}}\cdot {\mathrm{\text{g}}}^{-1}$ for other nanofibers) when the current density was recovered to the initial value ($40\mathrm{\text{mA}}\cdot {\mathrm{\text{g}}}^{-1})$. Electrochemical impedance spectroscopic measurements confirmed that the conductivity of the electrode was $6.3\times 10^{-1}\mathrm{\text{S}}\cdot {\mathrm{\text{cm}}}^{-1}$, which is higher than that of bare mesoporous Ag@TiO₂ ($1.99\times 10^{-5}\mathrm{\text{S}}\cdot {\mathrm{\text{cm}}}^{-1}$). Thus, one-dimensional mesoporous graphene@Ag@TiO₂ nanofibers can be regarded as a promising anode material for LIBs.

The graphene/silicon oxide/polypyrrole (G/SiO_x/PPY) material was prepared in this paper. The G/SiO_x/PPY material has good electrochemical performances including high capacity and cyclic stability. It has 2068/2130mAh g${}^{-1}$ of capacity after 100th charge/discharge cycle at 200mAg${}^{-1}$ of current density and 575/569mAhg${}^{-1}$ of capacity after 100th charge/discharge cycle at 2000mA g${}^{-1}$ of current density when G/SiO_x molar ratio is 1:5. Its capacity increases but its cyclic stability decreases with G/SiO_x molar ratio decreasing from 1:1 to 1:3 and 1:5. The electrochemical performance improvement of the G/SiO_x/PPY material is due to the synergetic effect of graphene and polypyrrole, which improve the conductivity of SiO_x and prevent its dropping from the surface of the electrode caused by the stress due to the volume expansion and shrinkage in charge/discharge cycles.

A mesoporous silica bearing uniformly distributed copper oxide nanoparticles (CuO@mesoporous SiO₂) was prepared through silica nanocasting copper metal organic frameworks (MOFs) followed by calcination. The nanocasting filled the micropores of MOFs with silica and then, the calcination removed the organic linker in MOFs and converted copper metal ions into CuO particles, resulting in the CuO@mesoporous SiO₂ architecture. The characterization results indicated that the final product basically maintained the original MOF morphology and the mesoporous silica effectively prevented the aggregation of nanoparticles. In addition, the CuO@mesoporous SiO₂ exhibited a superior activity for catalyzing the oxidation of styrene, which could be attributed to the fact that the dispersed CuO particles in mesoporous silica provided more accessible catalytic sites and better stability. This work provides a new strategy to prepare nanoparticles@mesoporous silica with adjustable morphology structure, which has a promising potential in the field of heterogeneous catalysis.