Facilely Direct Construction, White-Light Emission, and Color-Adjustable Luminescence of LaF3 :Pr3+ @SiO2 Yolk-Shell Nanospheres with Moisture Resistance.

Poor water stability and single luminous color are the major drawbacks of the most phosphors reported. Therefore, it is important to realize multicolor luminescence in a phosphor with single host and single activator as well as moisture resistance. LaF3 :Pr3+ @SiO2 yolk-shell nanospheres are facilely obtained by a designing new technology of a simple and cost-effective electrospray ionization combined with a dicrucible fluorating technique without using protective gas. In addition, tunable photoluminescence, especially white-light emission, is successfully obtained in LaF3 :Pr3+ @SiO2 yolk-shell nanospheres by adjusting Pr3+ ion concentrations, and the luminescence mechanism of Pr3+ ion is advanced. Compared with the counterpart LaF3 :Pr3+ nanospheres, the water stability of LaF3 :Pr3+ @SiO2 yolk-shell nanospheres is improved by 15% after immersion in water for 72 h, and the fluorescence intensity can be maintained at 86% of the initial intensity. Furthermore, by treating the yolk-shell nanospheres with hydrofluoric acid, it is not only demonstrated that the shell-layer is SiO2 but also core-LaF3 :Pr3+ nanospheres are obtained. Particularly, only fluorination procedure among the halogenation can produce such special yolk-shell nanospheres, the formation mechanism of yolk-shell nanospheres is proposed detailedly based on the sound experiments and a corresponding new technology is built. These findings broaden practical applications of LaF3 :Pr3+ @SiO2 yolk-shell nanospheres.

P-Doped Ni/NiO Heterostructured Yolk-Shell Nanospheres Encapsulated in Graphite for Enhanced Lithium Storage.

The development of high-efficiency lithium-ion battery electrodes composed of recycled materials is crucial for the commercialization of retired batteries, but it remains a significant barrier. The usage and recycling of spent graphite are encouraged by the huge number of batteries that are going to be dismantled. Here, an anode made of phosphorus-doped Ni/NiO yolk-shell nanospheres embedded on wasted graphite is developed. Electroless deposition and a subsequent heat-treatment procedure are used to make it in a methodical manner. The internal vacuum space of the nanospheres mitigates volume expansion and facilitates Li+ diffusion, whereas the embedded metallic Ni and conductive graphite layer expedite charge transfer. The optimal reusable composite electrode is ecologically benign and has high specific capacities (724 mAh g-1 at 0.1 A g-1 ) as well as outstanding cycle stability (500 cycles). The unusual 3D sandwich-like arrangement with strong spent graphite, the yolk-shell hetero-structure, continuous electron/ion transport routes, and attractive structure stability all contribute to this degree of performance. Such a nanoscale design and engineering strategy not only provides a green recovery method for anode graphite, but also enlightens other nanocomposites to boost their lithium storage performance.

The dependence of Cu2O morphology on different surfactants and its application for non-enzymatic glucose detection.

Herein, the Cu2O yolk-shell nanospheres, nanocubes and microcubes were successfully prepared by a simple seed-medium process. The formation of the Cu2O yolk-shell nanospheres can be attributed to the self-assembly process caused by the introduction of the seed medium. The formation mechanism of our obtained Cu2O yolk-shell nanospheres and the dependence of Cu2O morphology on different surfactants have been studied. The obtained samples were applied in the field of non-enzymatic glucose detection. The electrochemical response characteristics of the modified electrodes toward glucose were investigated by cyclic voltammetry (CV) and chronoamperometry (CA). The electrode modified with C-Cu2O (obtained by using CTAB as surfactant) shared the highest sensitivity of 3123 µAmM-1 cm-2, whereas, the electrode modified with S-Cu2O (obtained by using SDBS as surfactant) exhibited the lowest LOD of 0.87 µM and the widest linear range of 0.05-10.65 mM. All obtained sensors showed fast response to the addition of glucose. The obtained electrodes showed better responses to glucose than other coexisting interferences, indicating that the obtained electrodes had the acceptable selectivity to glucose. In addition, the stability for 5 consecutive weeks had also been studied and exhibited satisfactory results. The obtained electrode was also used to detect the glucose content in real serum. The acceptable selectivity, stability together with the excellent sensing ability in real serum make the obtained electrodes a potential for practical applications.

Ethanol Gas Detection Using a Yolk-Shell (Core-Shell) α-Fe2O3 Nanospheres as Sensing Material.

Three-dimensional (3D) nanostructures of α-Fe2O3 materials, including both hollow sphere-shaped and yolk-shell (core-shell)-shaped, have been successfully synthesized via an environmentally friendly hydrothermal approach. By expertly adjusting the reaction time, the solid, hollow, and yolk-shell shaped α-Fe2O3 can be selectively synthesized. Yolk-shell α-Fe2O3 nanospheres display outer diameters of 350 nm, and the interstitial hollow spaces layer is intimately sandwiched between the inner and outer shell of α-Fe2O3 nanostructures. The possible growth mechanism of the yolk-shell nanostructure is proposed. The results showed that the well-defined bilayer interface effectively enhanced the sensing performance of the α-Fe2O3 nanostructures (i.e., yolk-shell α-Fe2O3@α-Fe2O3), owing predominantly to the unique nanostructure, thus facilitated the transport rate and augmented the adsorption quantity of the target gas molecule under gas detection.