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Water-soluble carbon dots (CDs) have been successfully synthesized by green-one-pot hydrothermal method. The CDs with small particle size exhibit fairly good water solubility, tunable photoluminescence, up-converted photoluminescence, and low toxicity. What is more, the as-prepared CDs were successfully applied in the field of cell image. [ABSTRACT FROM AUTHOR]

Foam-like three dimensional mesoporous NiO on Ni foam was fabricated via facile hydrothermal etching and subsequent annealing treatment. The porous NiO consists of a large number of nanosheets with mean thickness about 50 nm, among which a large number of mesoscopic pores with size ranges from 100 nm to 1 μm distribute. The electrochemical performance of the as-prepared NiO-Ni as anode for lithium ion battery was studied by conventional charge/discharge test, which shows excellent cycle stability and rate capability. It exhibits initial discharge and charge capacities of 979 and 707 mA h g −1 at a charge/discharge rate of 0.7 C, which maintain of 747 and 738 mA h g −1 after 100 cycles. Even after 60 cycles at various rates from 0.06 to 14 C, the 10th discharge and charge capacities of the NiO-Ni electrode can revert to 699 and 683 mA h g −1 when lowering the charge/discharge rate to 0.06 C. [ABSTRACT FROM AUTHOR]

Searching for a cost-effective, high efficient and stable bifunctional electrocatalyst for overall water-splitting is critical to renewable energy systems. In this study, three-dimensional (3D) curved nanosheets of Mo-doped Ni 3 S 2 grown on nickel foam were successfully synthesized via a one-step hydrothermal process. The hydrogen-evolution reaction (HER) and the oxygen-evolution reaction (OER) in alkaline environment of this 3D catalyst are investigated in detail. The results show that it possesses lower overpotential, high current densities and small Tafel slopes both in OER and HER. For HER, the catalysts show excellent electrochemical performance, demonstrating a low over-potential of 212 mV at 10 mA cm −2 with a large decrease of 127 mV compared to the undoped Ni 3 S 2 . And it also shows a lower overpotential of 260 mV at 10 mA cm −2 which decreases 30 mV for OER. In addition, it is only need 1.67 V for the overall water splitting at 10 mA cm −2 which is 70 mV. It found that the Mo element would change the morphology of Ni 3 S 2 and induce much more active sites for HER and OER. The as-prepared Mo-doped Ni 3 S 2 bi-functional electrocatalyst could act as the promising electrode materials for water splitting. [ABSTRACT FROM AUTHOR]

Abstract: A low-temperature hydrothermal method was developed to synthesize urchinlike γ-MnO2 nanostructures. Time-dependent evolutions of morphology and crystallinity were investigated to explore the growth mechanism of the γ-MnO2 urchins. The results show that the growth process of the γ-MnO2 urchins occurs in two main stages, which are the generation of γ-MnO2 microspheres and the following epitaxial growth of γ-MnO2 nanoneedles on the surface of the initial microspheres. Microwave absorption properties of the urchinlike γ-MnO2 nanostructures were studied in terms of complex permittivity and permeability. An effective absorption bandwidth (reflection loss lower than −10dB) of 8.8GHz was achieved from the γ-MnO2/paraffin wax composite. [Copyright &y& Elsevier]

• A novel 3D core-shell structed catalyst with metallic Mo-Ni nanoparticles was constructed. • The introduced Mo-Ni would make NiFe LDH nanosheets uniformly growth and provide a rapidly electron transfer channel. • The electrochemistry of 134 mV, 278 mV and 1.64 V (HER, OER, overall water splitting) at 100 mA cm–2 can achieve. It is still a great challenge to develop efficient and stable monolithic electrocatalysts with effective cost and abundant natural resources. Herein, a 3D structured NiFe layered double hydroxide (NiFeLDH) nanosheets rationally decorated on MoNi/NiMoO x nanowires array supported on Ni foam (MoNi/NiMoO x @NiFe LDH) are fabricated by an in-situ growth process is firstly reported. The results show that MoNi alloys can build a fast electron transport channel, thus improving the efficiency of the electrocatalyst. And the ultrathin NiFe LDH nanosheets would provide abundant exposed defects and catalytic active sites. A low overpotential (278 mV at 100 mA cm−2) and Tafel slope (44.7 mV dec−1) for oxygen evolution reaction, and overpotential (134 mV at 100 mA cm−2) and Tafel slope of 81.0 mV dec−1 for hydrogen evolution reaction in 1 M KOH can achieved. The overall water splitting system composed with 3D core–shell catalyst (MoNi/NiMoO x @NiFe LDH) and MoNi/NiMoO x nanowire arrays, which can obtain 100 mA cm−2 at a voltage of 1.64V, even superior to the benchmark of IrO 2 (+) // Pt/C (-). Image, graphical abstract [ABSTRACT FROM AUTHOR]

Inexpensive metal-based electrocatalyst with excellent stability and activity for efficient hydrogen evolution reaction is the most critical issue for large-scaled water splitting. However, the electricity kinetics in alkaline is relatively sluggish than in acid owing to the concentration of protons in alkaline is low. Thus, accurate structural designs to obtain more protons in the water dissociation on the surface of catalyst are necessary. In this work, a defect-rich MoP is encapsulated with carbon shell, which precisely regulated to distinguish the affection on hydrogen evolution reaction. The synergistic effect between carbon shell and defective sites is identified by the free energy and charge distribution density for water/hydrogen adsorption in hydrogen evolution via a density functional theory calculation. The results show that the lattice defects and the carbon shells play a unique role in enhancing catalytic performance, which the lattice defects decide the active sites and the thinner carbon shell would enhance its activity. The optimal overpotential in alkaline media of this designed MoP/C is 100 mV at 10 mA cm−2, its Tafel slope is 67.4 mV dec−1, and also exhibits a long-term stability for 12 h. • Structure disordering and carbon shell on MoP precisely regulated. • Low onset overpotential (30 mV), small Tafel slope (67.4 mV·dec−1) can achieved in alkaline media. • Synergistic effect between lattice defects and carbon shell are considered to enhance HER catalytic performance. [ABSTRACT FROM AUTHOR]

Bio-thiols play an important role in living organisms. Both elevated levels and deficiency of bio-thiols will induce some diseases, such as cardiovascular disease and Alzheimer's diseases, skin lesions, and weakness. Therefore, fast and accurate detection of bio-thiols is of great significance. We have synthesized a ratiometric probe that can respond to bio-thiols with the fluorescence intensity at 568 nm (F 568) increasing and taht at 420 nm (F 420) decreasing. The responding process reaches equilibration in 1 min in the present of Cys or Hcy while in about 50 min with GSH. This probe can further detect bio-thiols in human breast cancer cells (MDA-MB-231) by confocal laser scanning microscope. Fluorescent ratio (R Y/B) of yellow channel with blue channel increase as reacting with bio-thiols in cells. Ratiometric probe SH-1 can realize the fast detecting of bio-thiols with R Y/B as detection signal both in vitro and in living cells. Image 1 • Rapidly respond to Cys or Hcy and F 568 reach the highest intensity in 1 min. • Imaging bio-thiols with R Y/B as detection signal in living cells and R Y/B shows obvious change (form <5 to >40). • Both the probe SH-1 and responding product SH-1-P are low toxicity. [ABSTRACT FROM AUTHOR]