Understanding the Role of Few-Layer Graphene Nanosheets in Enhancing the Hydrogen Sorption Kinetics of Magnesium Hydride

The catalytic effects of few-layer, highly wrinkled graphene nanosheet (GNS) addition on the dehydrogenation/rehydrogenation performance of MgH₂ were investigated. It was found that MgH₂–5 wt %GNSs nanocomposites prepared by ball milling exhibit relatively lower sorption temperature, faster sorption kinetics, and more stable cycling performance than that of pure-milled MgH₂. The dehydrogenation step confirms that the Avrami exponent <i>n</i> increases from 1.22 to 2.20 by the Johnson–Mehl–Avrami (JMA) formalism when the desorption temperature is reduced from 350 °C to 320 °C and 300 °C, implying that a change in the decomposition temperature can alter the mechanism during the dehydrogenation process. For rehydrogenation, the Avrami value <i>n</i> is close to 1; further study by several models coincident with <i>n</i> = 1 reveals that the absorption process of the MgH₂–5 wt %GNSs sample conforms to the Mampel equation formulated through the random nucleation approach and that the nature of the absorption mechanism does not change within the temperature range studied. Furthermore, microstructure analysis demonstrated that the defective GNSs are distributed uniformly among the MgH₂ particles and that the grain size of the MgH₂–5 wt %GNSs nanocomposite is approximately 5–9 nm. The efficient metal-free catalytic dehydrogenation/rehydrogenation of MgH₂ can be attributed to the coupling of the nanosize effect and defective GNSs

Layered Na₂Ti₃O₇/MgNaTi₃O₇/Mg_0.5NaTi₃O₇ Nanoribbons as High-Performance Anode of Rechargeable Mg-Ion Batteries

We report on layered Na₂Ti₃O₇/MgNaTi₃O₇/Mg_0.5NaTi₃O₇ nanoribbons for reversible electrochemical Mg storage. First, Mg²⁺ intercalation with irreversible Na⁺ deintercalation takes place in the first discharge process (Na₂Ti₃O₇ + Mg²⁺ + e^– → MgNaTi₃O₇ + Na⁺). Then, reversible Mg²⁺ insertion–extraction occurs in subsequent cycling processes (MgNaTi₃O₇ ↔ Mg_0.5NaTi₃O₇ + 0.5Mg²⁺ + e^–). This reaction with repeatable 0.5 M Mg²⁺ occupying the sites of Na⁺ coordinated to seven oxygen atoms offers a theoretical capacity of 88 mA h g^–1 (78 mA h g^–1 in practical test with Mg²⁺ electrolyte). Furthermore, the MgNaTi₃O₇ was used to assemble full Mg-ion batteries (MIBs) with Mg­(ClO₄)₂–diglyme electrolyte and V₂O₅ cathode. The cell delivers a reversible capacity of 75 mA h g^–1 corresponding to an energy density of 53 Wh kg^–1. This work displays the potential of layered Na₂Ti₃O₇/MgNaTi₃O₇/Mg_0.5NaTi₃O₇ as the anode of MIBs

Layered Na₂Ti₃O₇/MgNaTi₃O₇/Mg_0.5NaTi₃O₇ Nanoribbons as High-Performance Anode of Rechargeable Mg-Ion Batteries

We report on layered Na₂Ti₃O₇/MgNaTi₃O₇/Mg_0.5NaTi₃O₇ nanoribbons for reversible electrochemical Mg storage. First, Mg²⁺ intercalation with irreversible Na⁺ deintercalation takes place in the first discharge process (Na₂Ti₃O₇ + Mg²⁺ + e^– → MgNaTi₃O₇ + Na⁺). Then, reversible Mg²⁺ insertion–extraction occurs in subsequent cycling processes (MgNaTi₃O₇ ↔ Mg_0.5NaTi₃O₇ + 0.5Mg²⁺ + e^–). This reaction with repeatable 0.5 M Mg²⁺ occupying the sites of Na⁺ coordinated to seven oxygen atoms offers a theoretical capacity of 88 mA h g^–1 (78 mA h g^–1 in practical test with Mg²⁺ electrolyte). Furthermore, the MgNaTi₃O₇ was used to assemble full Mg-ion batteries (MIBs) with Mg­(ClO₄)₂–diglyme electrolyte and V₂O₅ cathode. The cell delivers a reversible capacity of 75 mA h g^–1 corresponding to an energy density of 53 Wh kg^–1. This work displays the potential of layered Na₂Ti₃O₇/MgNaTi₃O₇/Mg_0.5NaTi₃O₇ as the anode of MIBs

One-step preparation of durable pH-responsive polyurethane foam for oil/water separation

The smart responsive materials have become one of the hottest areas of research in oil/water separation field and there are various studies on preparation technologies. However, most of the materials reported were prepared by coating or coupling to attach functional polymer to substrates, which generally had unstable physical and chemical properties and were difficult to be applied in harsh environments. In this work, we fabricated a smart and durable oil/water separation material by one-step foaming method to graft pH-responsive copolymer onto a polyurethane foam (PUF) substrate. The foam exhibited reversible wettability under different pH environments, had excellent oil adsorption capacity (24.78–64.27g/g) and high oil/water separation efficiency (above 98%). Besides, the foam also showed stable performance and excellent recyclability in a series of durability experiments, including mechanical abrasion, light radiation and chemical immersion. The foam with simple preparation process and excellent stability will have promising application prospects in the field of oil/water separation.</p

FST expression in the mouse ovary.

<p>Western blotting was performed to examine the mouse ovary FST protein levels from 17.5 dpc to 7 dpp, which were normalized to β-actin (A and B). Significant differences are indicated by * (<i>P</i> < 0.05).</p

Ultrasmall TiO₂ Nanoparticles in Situ Growth on Graphene Hybrid as Superior Anode Material for Sodium/Lithium Ion Batteries

To inhibit the aggregation of TiO₂ nanoparticles and to improve the electrochemical kinetics of TiO₂ electrode, a hybrid material of ultrasmall TiO₂ nanoparticles in situ grown on rGO nanosheets was obtained by ultraphonic and reflux methods. The size of the TiO₂ particles was controlled about 10 nm, and these particles were evenly distributed across the rGO nanosheets. When used for the anode of a sodium ion battery, the electrochemical performance of this hybrid TiO₂@rGO was much improved. A capacity of 186.6 mAh g^–1 was obtained after 100 cycles at 0.1 A g^–1, and 112.2 mAh g^–1 could be maintained at 1.0 A g^–1, showing a high capacity and good rate capability. On the basis of the analysis of cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS), the achieved excellent electrochemical performance was mainly attributed to the synergetic effect of well-dispersed ultrasmall TiO₂ nanoparticles and conductive graphene network and the improved electrochemical kinetics. The superior electrochemical performance of this hybrid material on lithium storage further confirmed the positive effect of rGO

Germ cell apoptosis in FST288-treated mice ovaries.

<p>Ovaries at 17.5 dpc were cultured alone (as a control) or with 500 ng/mL FST288 for 4 days prior to apoptosis assay (TUNEL). After culture ovaries were fixed and sectioned, a TUNEL assay was performed on the sections. No significant difference in oocyte apoptosis was observed between control and FST288-treated ovaries (A-D, arrows; TUNEL-positive oocytes). Populations of apoptotic oocytes and total oocytes per section in each treatment group were quantified (E and F). Scale bars: 40 μm (A-D).</p

Proliferation of granulosa cells in FST288-treated ovaries.

<p>Ovaries at 17.5 dpc were cultured alone (as a control) or with 500 ng/mL FST288 for BrdU incorporation assays. After 4 days of culture, when compared to granulosa cells of control ovaries (A-C, arrows; BrdU-positive granulosa cells), BrdU incorporation into granulosa cells of FST288-treated ovaries was reduced (D-F, arrows; BrdU-positive granulosa cells), particularly near the ovarian cortex. Similarly, BrdU incorporation into granulosa cells near the periphery of FST288-treated ovaries (J-L) was reduced relative to granulosa cells of control ovaries after 7 days of culture (G-I, arrows; BrdU-positive granulosa cells). Almost all of the somatic cells near the ovarian cortex were BrdU-negative (J-L). Scale bars: 40 μm (A-L).</p

Phenotypes of ovary cultures treated with FST288.

<p>Ovaries at 17.5 dpc were cultured for 7 days without treatment (as a control) or with 500 ng/mL FST288. After culture, ovaries were fixed and sectioned, and then the shape and number of total germ cells and growing follicles were examined. Control ovaries had mostly primordial follicles containing small oocytes surrounded by flattened pre-granulosa cells (A and B, arrows, enlarged in C), while FST288-treated ovaries had a greater number of germ cells within nests (D and E, black boundaries, enlarged in F) compared to control ovaries. Follicle populations in the largest cross-section of control and FST288-treated ovaries were quantified (G). Western blot analysis revealed a dramatic decrease of the p-smad2 level in FST288-treated ovaries relative to control group (H). Scale bars: 40 μm (A, B, D and E). Smad2 was measured as internal control. Significant differences between control and FST288-treated ovaries are indicated by * (P < 0.05).</p

In Situ Preparation of 1D Co@C Composite Nanorods as Negative Materials for Alkaline Secondary Batteries

Cobalt-based coordination compounds were successfully prepared via employing nitrilotriacetic acid (NTA) as a complexing agent through a mild surfactant-free solvothermal process. Cobalt ions are linked with the amino group or carboxyl groups of NTA to become one-dimensional nanorods that can be proved by Fourier transform infrared measurement findings. The morphologies of the precursor Co–NTA highly depend on the solvent composition, the reaction time and temperature. The probable growth mechanism has been proposed. After heat treatment, the Co–NTA precursor can be completely converted into Co@C nanorods assembled by numerous core–shell-like Co@C nanoparticles, which preserved the rodlike morphology. The as-prepared Co@C composites display a rodlike morphology with 4 μm length and 100 nm diameter. The electrochemical performances of this novel Co@C material as the alkaline secondary Ni/Co battery negative electrode have been systematically researched. The discharge capacity of the Co@C-1 composite electrode can attain 609 mAh g^–1 and retains about 383.3 mAh g^–1 after 120 cycles (the discharge current density of 500 mA g^–1). The novel material exhibits a high discharge capacity of 610 and 470 mAh g^–1 at discharge currents of 100 and 1000 mA g^–1, respectively. This suggests that approximately 77% of the discharge capacity is kept when the discharge current density is increased to 1000 mA g^–1 (10 times the initial current density of 100 mA g^–1). The excellent electrochemical properties could be ascribed to the porous channels of the novel Co@C materials, which is beneficial to electrolyte diffusion and electrons and ions transportation