China West Normal University

Iron is the cheapest and one of the most abundant transition metals. Natural [FeFe]-hydrogenases exhibit remarkably high activity in hydrogen evolution, but they suffer from high oxygen sensitivity and difficulty in scale-up. Herein, an FeP nanowire array was developed on Ti plate (FeP NA/Ti) from its β-FeOOH NA/Ti precursor through a low-temperature phosphidation reaction. When applied as self-supported 3D hydrogen evolution cathode, the FeP NA/Ti electrode shows exceptionally high catalytic activity and good durability, and it only requires overpotentials of 55 and 127 mV to afford current densities of 10 and 100 mA cm(2) , respectively. The excellent electrocatalytic performance is promising for applications as non-noble-metal HER catalyst with a high performance-price ratio in electrochemical water splitting for large-scale hydrogen fuel production.

It is highly desirable but challenging to develop bifunctional catalysts for efficiently catalyzing both the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) in energy storage and conversion systems. Here a simple yet cost-effective strategy is developed to fabricate nitrogen and phosphorus dual-doped graphene/carbon nanosheets (N,P-GCNS) with N,P-doped carbon sandwiching few-layers-thick graphene. The as-prepared N,P-GCNS shows outstanding catalytic activity toward both ORR and OER with a potential gap of 0.71 V between the OER potential at a current density of 10 mA cm –2 and the ORR potential at a current density of −3 mA cm –2, illustrating that it is the best metal-free bifunctional electrocatalysts reported to date. The superb bifunctional catalytic performance is attributed to the synergistic effects between the doped N and P atoms, the full exposure of the active sites on the surface of the N,P-GCNS nanosheets, the high conductivity of the incorporated graphene, and the large surface area and hierarchical pores for sufficient contact and rapid transportation of the reactants.

We describe the current plans for a spectroscopic survey of millions of stars in the Milky Way galaxy using the Guo Shou Jing Telescope (GSJT, formerly called the Large sky Area Multi-Object fiber Spectroscopic Telescope — LAMOST). The survey will obtain spectra for 2.5 million stars brighter than r < 19 during dark/grey time, and 5 million stars brighter than r < 17 or J < 16 on nights that are moonlit or have low transparency. The survey will begin in the fall of 2012, and will run for at least four years. The telescope's design constrains the optimal declination range for observations to 10° < δ < 50°, and site conditions lead to an emphasis on stars in the direction of the Galactic anticenter. The survey is divided into three parts with different target selection strategies: disk, anticenter, and spheroid. The resulting dataset will be used to study the merger history of the Milky Way, the substructure and evolution of the disks, the nature of the first generation of stars through identification of the lowest metallicity stars, and star formation through study of open clusters and OB associations. Detailed design of the LAMOST Experiment for Galactic Understanding and Exploration (LEGUE) survey will be completed in summer 2012, after a review of the results of the pilot survey.

A simple, economical, and green method for the preparation of water-soluble, high-fluorescent carbon quantum dots (C-dots) has been developed via hydrothermal process using aloe as a carbon source. The synthesized C-dots were characterized by atomic force microscope (AFM), transmission electron microscopy (TEM), fluorescence spectrophotometer, UV-vis absorption spectra as well as Fourier transform infrared spectroscopy (FTIR). The results reveal that the as-prepared C-dots were spherical shape with an average diameter of 5 nm and emit bright yellow photoluminescence (PL) with a quantum yield of approximately 10.37%. The surface of the C-dots was rich in hydroxyl groups and presented various merits including high fluorescent quantum yield, excellent photostability, low toxicity and satisfactory solubility. Additionally, we found that one of the widely used synthetic food colorants, tartrazine, could result in a strong fluorescence quenching of the C-dots through a static quenching process. The decrease of fluorescence intensity made it possible to determine tartrazine in the linear range extending from 0.25 to 32.50 μM, This observation was further successfully applied for the determination of tartrazine in food samples collected from local markets, suggesting its great potential toward food routine analysis. Results from our study may shed light on the production of fluorescent and biocompatible nanocarbons due to our simple and environmental benign strategy to synthesize C-dots in which aloe was used as a carbon source.

This review summarizes the recent research progress made in nanostructured metal nitrides for electrochemical and photo(electro)chemical water splitting.

Abstract Titanium‐based catalysts are needed to achieve electrocatalytic N 2 reduction to NH 3 with a large NH 3 yield and a high Faradaic efficiency (FE). One of the cheapest and most abundant metals on earth, iron, is an effective dopant for greatly improving the nitrogen reduction reaction (NRR) performance of TiO 2 nanoparticles in ambient N 2 ‐to‐NH 3 conversion. In 0.5 m LiClO 4 , Fe‐doped TiO 2 catalyst attains a high FE of 25.6 % and a large NH 3 yield of 25.47 μg h −1 mg cat −1 at −0.40 V versus a reversible hydrogen electrode. This performance compares favorably to those of all previously reported titanium‐ and iron‐based NRR electrocatalysts in aqueous media. The catalytic mechanism is further probed with theoretical calculations.

Metal-free phosphorus-doped graphene nanosheets (P-TRG) with large surface area (496.67 m2 g−1) and relatively high P-doping level (1.16 at.%) were successfully prepared by thermal annealing a homogenous mixture of graphene oxide and 1-butyl-3-methlyimidazolium hexafluorophosphate under argon atmosphere. It was found that the P atoms were substitutionally incorporated into the carbon framework and were partially oxidized, which created new active sites for the oxygen reduction reaction (ORR). Accordingly, the ORR catalytic performance of the P-doped graphene was demonstrated to be better than or at least comparable to that of the benchmark Pt/C catalyst.

Developing non-noble-metal hydrogen evolution reaction electrocatalysts with high activity is critical for future renewable energy systems. The direct growth of active phases on current collectors not only eliminates using polymer binder but also offers time-saving preparation of electrode. In this Letter, we develop self-supported FeP nanorod arrays on carbon cloth (FeP NAs/CC) via low-temperature phosphidation of its Fe 2 O 3 NAs/CC. As a novel 3D hydrogen evolution cathode in acidic media, the FeP NAs/CC exhibits high catalytic activity and only needs an overpotential of 58 mV to afford current density of 10 mA/cm 2 . This electrode also works efficiently in both neutral and alkaline solutions.

Showing MOFs' true colors: An iron-based metal–organic framework, MIL-53(Fe), is explored as an enzyme mimic with intrinsic peroxidase-like activity. MIL-53(Fe) can catalyze the oxidation of different peroxidase substrates in the presence of H2O2 (see graphic; TMB=3,3′,5,5′-tetramethylbenzidine, OPD=o-phenylenediamine), providing a new and simple colorimetric detection of hydrogen peroxide and ascorbic acid.

MXene-derived TiO ₂ @C/g-C ₃ N ₄ heterojunctions exhibit superior performance for photocatalytic nitrogen reduction to ammonia under visible light irradiation.

The present communication reports the topotactic conversion of NiCo2O4 nanowires array on carbon cloth (NiCo2O4 NA/CC) into NiCo2S4 NA/CC, which is used as an efficient bifunctional electrocatalyst for water splitting with good durability and superior activity in 1.0 M KOH. This NiCo2S4 NA/CC electrode produces 100 mA cm(-2) at an overpotential of 305 mV for hydrogen evolution and 100 mA cm(-2) at an overpotential of 340 mV for oxygen evolution. To afford a 10 mA cm(-2) water-splitting current, the alkaline water electrolyzer made from NiCo2S4 NA/CC needs a cell voltage of 1.68 V, which is 300 mV less than that for NiCo2O4 NA/CC, and has good stability.

In this communication, we report that a Co-doped NiSe2 nanoparticles film electrodeposited on a conductive Ti plate (Co0.13Ni0.87Se2/Ti) behaves as a robust electrocatalyst for both HER and OER in strongly basic media, with good activity over a NiSe2/Ti counterpart. This Co0.13Ni0.87Se2/Ti catalytic electrode delivers 10 mA cm(-2) at an overpotential of 64 mV for HER and 100 mA cm(-2) at an overpotential of 320 mV for OER in 1.0 M KOH. A voltage of only 1.62 V is required to drive 10 mA cm(-2) for the two-electrode alkaline water electrolyzer using Co0.13Ni0.87Se2/Ti as an anode and cathode.

Abstract It is highly attractive, but still remains a huge challenge, to develop efficient non‐noble‐metal electrocatalysts for both the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) under neutral and alkaline conditions. In this paper, we report that CoP nanosheet arrays on carbon cloth (CoP NA/CC), derived from α‐Co(OH) 2 NA/CC, behaves as a three‐dimensional bifunctional water‐splitting catalyst electrode with high activity and durability in neutral and alkaline media. Such CoP NA/CC demands overpotentials of 145 and 52 mV to afford 10 mA cm −2 for the HER in 1.0 M phosphate buffer solution (PBS) and 1.0 M KOH, respectively, with much superior activity to α‐Co(OH) 2 NA/CC. It can be attributed to the more thermo‐neutral hydrogen adsorption free energy for CoP than α‐Co(OH) 2 , according to density functional theory calculations. This electrode also demonstrates superior OER activity over α‐Co(OH) 2 NA/CC and needs overpotentials of only 536 and 300 mV to drive 10 mA cm −2 at neutral and alkaline pH, respectively. The two‐electrode water electrolyzer using CoP NA/CC as both the cathode and anode shows a 2 mA cm −2 water‐splitting current at a cell voltage of 1.60 V in 1.0 M PBS and needs 1.65 V for 10 mA cm −2 under alkaline condition with excellent stability.

on the surface of SS mesh may be the active species for OER. The abundant and commercial availability, long-term stability and low-cost property of nickel foam and stainless steel mesh enable their large-scale practical application in water splitting.

It is attractive but still remains a big challenge to develop non-noble metal bifunctional electrocatalysts efficient for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) under alkaline conditions. Herein, an amorphous CoSe film electrodeposited on a Ti mesh (a-CoSe/Ti) is demonstrated to exhibit high electrocatalytic activity and stability for both reactions in 1.0 M KOH. It needs overpotentials of 292 and 121 mV to drive 10 mA cm(-2) for OER and HER, respectively. The two-electrode alkaline water electrolyzer affords a water-splitting current of 10 mA cm(-2) at a cell voltage of 1.65 V. This work offers an attractive cost-effective catalytic material toward full water splitting applications.

A Zn-doped Ni ₃ S ₂ nanosheet array on Ni foam (Zn-Ni ₃ S ₂ /NF) acts as a high-performance and durable electrocatalyst for the oxygen evolution reaction in 1.0 M KOH, driving a catalytic current density of 100 mA cm ⁻² at an overpotential of 330 mV, 90 mV less than that for Ni ₃ S ₂ /NF.

OBJECTIVES: Tanshinone I (Tan-I) is one of the vital fatsoluble monomer components, which extracted from Chinese medicinal herb Salvia miltiorrhiza Bunge. It has been shown that Tan-I exhibited anti-tumour activities on different types of cancers. However, the underlying mechanisms by which Tan-Ⅰ regulates apoptosis and autophagy in ovarian cancer remain unclear. Thus, this study aimed to access the therapy effect of Tan-Ⅰ and the underlying mechanisms. METHODS: Ovarian cancer cells A2780 and ID-8 were treated with different concentrations of Tan-Ⅰ (0, 1.2, 2.4, 4.8 and 9.6 μg/mL) for 24 hours. The cell proliferation was analysed by CCK8 assay, EdU staining and clone formation assay. Apoptosis was assessed by the TUNEL assay and flow cytometry. The protein levels of apoptosis protein (Caspase-3), autophagy protein (Beclin1, ATG7, p62 and LC3II/LC3I) and PI3K/AKT/mTOR pathway were determined by Western blot. Autophagic vacuoles in cells were observed with LC3 dyeing using confocal fluorescent microscopy. Anti-tumour activity of Tan-Ⅰ was accessed by subcutaneous xeno-transplanted tumour model of human ovarian cancer in nude mice. The Ki67, Caspase-3 level and apoptosis level were analysed by immunohistochemistry and TUNEL staining. RESULTS: Tan-Ⅰ inhibited the proliferation of ovarian cancer cells A2780 and ID-8 in a dose-dependent manner, based on CCK8 assay, EdU staining and clone formation assay. In additional, Tan-Ⅰ induced cancer cell apoptosis and autophagy in a dose-dependent manner in ovarian cancer cells by TUNEL assay, flow cytometry and Western blot. Tan-Ⅰ significantly inhibited tumour growth by inducing cell apoptosis and autophagy. Mechanistically, Tan-Ⅰ activated apoptosis-associated protein Caspase-3 cleavage to promote cell apoptosis and inhibited PI3K/AKT/mTOR pathway to induce autophagy. CONCLUSIONS: This is the first evidence that Tan-Ⅰ induced apoptosis and promoted autophagy via the inactivation of PI3K/AKT/mTOR pathway on ovarian cancer and further inhibited tumour growth, which might be considered as effective strategy.

Recent work, which treats the Hawking radiation as a semiclassical tunneling process at the horizon of the Schwarzschild and Reissner-Nordstr\"om spacetimes, indicates that the exact radiant spectrum is no longer pure thermal after considering the black hole background as dynamical and the conservation of energy. In this paper, we extend the method to investigate Hawking radiation as massless particles tunneling across the event horizon of the Kerr black hole and that of charged particles from the Kerr-Newman black hole by taking into account the energy conservation, the angular momentum conservation, and the electric charge conservation. Our results show that when self-gravitation is considered, the tunneling rate is related to the change of Bekenstein-Hawking entropy and the derived emission spectrum deviates from the pure thermal spectrum, but is consistent with an underlying unitary theory.

A synergetic architecture composed of nitrogen-doped carbon encapsulating cobalt and molybdenum carbide nanoparticles (Co _x Mo _y @NC) presents excellent performance towards both HER and OER catalysis in alkaline medium.

The Haber–Bosch process for industrial NH 3 production suffers from harsh reaction conditions and serious CO 2 emission. Electrochemical N 2 reduction offers a carbon-neutral alternative for more energy-saving NH 3 synthesis but requires active electrocatalysts for the N 2 reduction reaction (NRR). In this Letter, boron nanosheet (BNS) is proposed as an elemental two-dimensional (2D) material to effectively catalyze the NRR toward NH 3 synthesis with excellent selectivity. When tested in 0.1 M Na 2 SO 4, such BNS catalyst attains a high Faradaic efficiency of 4.04% and a large NH 3 yield of 13.22 μg h –1 mg cat –1 at −0.80 V vs reversible hydrogen electrode, with strong electrochemical durability. Density functional theory calculations suggest that the B atoms of both oxidized and H-deactivated BNS can catalyze the NRR more effectively than clean BNS, and the rate-determining step is the desorption process of the second NH 3 gas.