Ultra-rapid and highly efficient enrichment of organic pollutants via magnetic mesoporous nanosponge for ultrasensitive nanosensors.

Currently, owing to the single-molecule-level sensitivity and highly informative spectroscopic characteristics, surface-enhanced Raman scattering (SERS) is regarded as the most direct and effective detection technique. However, SERS still faces several challenges in its practical applications, such as the complex matrix interferences, and low sensitivity to the molecules of intrinsic small cross-sections or weak affinity to the surface of metals. Here, we show an enrichment-typed sensing strategy with both excellent selectivity and ultrahigh detection sensitivity based on a powerful porous composite material, called mesoporous nanosponge. The nanosponge consists of porous ß-cyclodextrin polymers immobilized with magnetic NPs, demonstrating remarkable capability of effective and fast removal of organic micropollutants, e.g., ~90% removal efficiency within ~1 min, and an enrichment factor up to ~103. By means of this current enrichment strategy, the limit of detection for typical organic pollutants can be significantly improved by 2~3 orders of magnitude. Consequently, the current enrichment strategy is proved to be applicable in a variety of fields for portable and fast detection, such as Raman and fluorescent sensing.

Shape-Controlled Hierarchical Flowerlike Au Nanostructure Microarrays by Electrochemical Growth for Surface-Enhanced Raman Spectroscopy Application.

How to fabricate Au nanostructures conveniently on microstructured/nanostructured arrays surface with low cost has become a crucial and urgent challenge. In this study, we demonstrate hierarchical flowerlike Au nanostructures with rich nanothorns (HF-AuNTs) through one-step electrochemical deposition. The morphology of the HF-AuNTs is easily manipulated by controlling the applied potential or precursor solution concentration of electrodeposition. The as-prepared HF-AuNTs possessing unique local morphology of thin petals and dense thorns are further applied in the Si micropit arrays to acquire HF-AuNTs microarrays. As an initial detection, these HF-AuNTs microarrays exhibit a fascinating surface-enhanced Raman spectroscopy consistency (relative standard deviation is 7.17%) and sensitivity with the limitation of crystal violet reaching to 10-10 M, and Rhodamine 6G reaching to 10-11 M. The HF-AuNTs microarrays with well-defined shape and elaborate structure may be applicated in SERS substrates, superhydrophobic materials, and so on.

Enhanced Energy Storage Performance of Lead-Free Capacitors in an Ultrawide Temperature Range via Engineering Paraferroelectric and Relaxor Ferroelectric Multilayer Films.

Industry has been seeking a thin-film capacitor that can work at high temperature in a harsh environment, where cooling systems are not desired. Up to now, the working temperature of the thin-film capacitor is still limited up to 200 °C. Herein, we design a multilayer structure with layers of paraferroelectric (Ba0.3Sr0.7TiO3, BST) and relaxor ferroelectric (0.85BaTiO3-0.15Bi(Mg0.5Zr0.5)O3, BT-BMZ) to realize optimum properties with a flat platform of dielectric constant and high breakdown strength for excellent energy storage performance at high temperature. Through optimizing the multilayer structure, a highly stable relaxor ferroelectric state is obtained for the BST/BT-BMZ multilayer thin-film capacitor with a total thickness of 230 nm, a period number N = 8, and a layer thickness ratio of BST/BT-BMZ = 3/7. The optimized multilayer film shows significantly improved energy storage density (up to 30.64 J/cm3) and energy storage efficiency (over 70.93%) in an ultrawide temperature range from room temperature to 250 °C. Moreover, the multilayer system also exhibits excellent thermal stability in such an ultrawide temperature range with a change of 5.15 and 12.75% for the recoverable energy density and energy storage efficiency, respectively. Our results demonstrate that the designed thin-film capacitor is promising for the application in a harsh environment and open a way to tailor a thin-film capacitor toward higher working temperature with enhanced energy storage performance.

Regulating Surface and Grain-Boundary Structures of Ni-Rich Layered Cathodes for Ultrahigh Cycle Stability.

The wide applications of Ni-rich LiNi1- x-y Cox Mny O2 cathodes are severely limited by capacity fading and voltage fading during the cycling process resulting from the pulverization of particles, interfacial side reactions, and phase transformation. The canonical surface modification approach can improve the stability to a certain extent; however, it fails to resolve the key bottlenecks. The preparation of Li(Ni0.4 Co0.2 Mn0.4 )1- x Tix O2 on the surface of LiNi0.8 Co0.1 Mn0.1 O2 particles with a coprecipitation method is reported. After sintering, Ti diffuses into the interior and mainly distributes along surface and grain boundaries. A strong surface and grain boundary strengthening are simultaneously achieved. The pristine particles are fully pulverized into first particles due to mechanical instability and high strains, which results in serious capacity fading. In contrast, the strong surface and the grain boundary strengthening can maintain the structural integrity, and therefore significantly improve the cycle stability. A general and simple strategy for the design of high-performance Ni-rich LiNi1- x - y Cox Mny O2 cathode is provided and is applicable to surface modification and grain-boundary regulation of other advanced cathodes for batteries.

Self-assembling behavior and interface structure in vertically aligned nanocomposite (Pr0.5Ba0.5MnO3)1-x:(CeO2)x films on (001) (La,Sr)(Al,Ta)O3 substrates.

Heteroepitaxial oxide-based nanocomposite films possessing a variety of functional properties have attracted tremendous research interest. Here, self-assembled vertically aligned nanocomposite (Pr0.5Ba0.5MnO3)1-x:(CeO2)x (x = 0.2 and 0.5) films have been successfully grown on single-crystalline (001) (La,Sr)(Al,Ta)O3 substrates by the pulsed laser deposition technique. Self-assembling behavior of the nanocomposite films and atomic-scale interface structure between Pr0.5Ba0.5MnO3 matrix and CeO2 nanopillars have been investigated by advanced electron microscopy techniques. Two different orientation relationships, (001)[100]Pr0.5Ba0.5MnO3//(001)[1-10]CeO2 and (001)[100]Pr0.5Ba0.5MnO3//(110)[1-10]CeO2, form between Pr0.5Ba0.5MnO3 and CeO2 in the (Pr0.5Ba0.5MnO3)0.8:(CeO2)0.2 film along the film growth direction, which is essentially different from vertically aligned nanocomposite (Pr0.5Ba0.5MnO3)0.5:(CeO2)0.5 films having only (001)[100]Pr0.5Ba0.5MnO3//(001)[1-10]CeO2 orientation relationship. Both coherent and semi-coherent Pr0.5Ba0.5MnO3/CeO2 interface appear in the films. In contrast to semi-coherent interface with regular distribution of interfacial dislocations, interface reconstruction occurs at the coherent Pr0.5Ba0.5MnO3/CeO2 interface. Our findings indicate that epitaxial strain imposed by the concentration of CeO2 in the nanocomposite films affects the self-assembling behavior of the vertically aligned nanocomposite (Pr0.5Ba0.5MnO3)1-x:(CeO2)x films.

Mesoporous gold nanoparticles for photothermal controlled anticancer drug delivery.

Aim: To realize the transit and release of cancer drug exactly as well as high drug loading ratio, we reported a biocompatible and temperature responsive controlled drug delivery system based on 3D mesoporous structured Au networks. Materials & methods: Here, we filled the hollow interiors of Au networks with a phase-change material so that the drug release was easily regulated by controlling the temperature only. Results: Thanks to the high near-infrared reflectance absorbance and mesoporous structure, the Au-PEG + lauric acid/doxorubicin system showed a strong photothermal conversion efficiency, high drug-loading ratio (54.2% for doxorubicin) and controlled drug release. Conclusion: This system revealed great advantages in photothermal therapy and chemotherapy, offering an obvious synergistic effect in cancer treatment.

Pyrolytic synthesis of MoO3 nanoplates within foam-like carbon nanoflakes for enhanced lithium ion storage.

MoO3 as electrode material for lithium ion batteries (LIBs) suffers from the poor ionic and electronic conductivity, while hybridizing nanostructured MoO3 with carbon-based materials is regarded as an efficient strategy. Herein, we report the facile synthesis of MoO3 nanoplates within foam-like carbon nanoflakes (CNFs) via the pyrolysis of molybdenum 2-ethtlhexanoate (C48H90MoO12) at a low temperature of 300 °C under ambient atmosphere. Mixing C48H90MoO12 with the highly porous foam-like CNFs allows the sufficient pyrolysis of Mo precursor, which can readily crystallize into MoO3 with plate morphology. The loading amount of MoO3 within CNFs can be easily and precisely controlled by adjusting the relative amount of C48H90MoO12/CNFs, while the plate morphology of MoO3 can be well preserved. The structural characteristics as well as the formation mechanism are investigated. When used as anode material for LIBs, optimized MoO3/CNFs displays superior lithium storage performance, delivering a high discharge capacity of 791 mA h/g after 100 cycles at 500 mA/g and even ∼600 mA h/g at a high rate of 2000 mA/g. Moreover, the present pyrolysis synthetic strategy can be generally applied for low-cost and large-scale fabrication of various MoO3/carbon nanocomposites, which demonstrates great potential in the development of high-performance electrodes for electrochemical energy-storage.

Green, Biodegradable, Underwater Superoleophobic Wood Sheet for Efficient Oil/Water Separation.

Superwettable (by water or oil) materials have been used in oil/water separation to cope with the growing oily industrial sewage discharge and oil spill accidents. The artificial superwetting materials for oil/water separation that have been previously reported are expensive, and using them usually causes secondary pollution, so practical, large-scale uses of those materials are limited. Here, we find that wood sheet shows underwater superoleophobicity and low oil adhesion in water, resulting from its strong capacity of absorbing water. A through-microhole array was created on the wood sheet surface by a simple mechanical drilling process. The prewetted porous sheet had great ability to separate the mixtures of water and oil with high separation efficiency. Wood is a low cost, green, and natural eco-friendly material; therefore, we believe that such a simple, low-cost, efficient, and green route of large-scale oil/water separation has great potential to practically solve the pollution problems caused by oil spill and oily industrial wastewater.

Phase Evolution, Crystal Structure, and Microwave Dielectric Properties of Water-Insoluble (1 - x)LaNbO4-xLaVO4 (0 ≤ x ≤ 0.9) Ceramics.

In the present work, a series of low-temperature firing scheelite structured microwave dielectric in water-insoluble La2O3-Nb2O5-V2O5 system was prepared via the traditional solid-state reaction method. Backscattering electron diffraction, X-ray diffraction (XRD), energy-dispersive analysis, and Rietveld refinements were performed to study the phase evolution and crystal structure. In the full composition range of (1 - x)LaNbO4-xLaVO4 (0 ≤ x ≤ 0.9) ceramics, at least four typical phase regions including monoclinic fergusonite, tetragonal sheelite, B-site ordered sheelite, and composite of monoclinic LaVO4 and tetragonal sheelite phases can be detected according to XRD analysis. The variations of relative dielectric constant εr, quality factor Q × f, and resonant frequency τf could be attributed to Nb/V-O bond ionicity, lattice energy, and the coefficient of thermal expansion. Infrared reflectivity spectra analysis revealed that ion polarization contributed mainly to the permittivity in microwave frequencies ranges. Furthermore, the 0.7LaNbO4-0.3LaVO4 ceramic sintered at 1160 °C possessed excellent microwave dielectric properties with an εr of ∼17.78, a Q × f of ∼75 940 GHz, and a τf of ca. -36.8 ppm/°C. This series of materials might be good candidate for microwave devices.