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Bismuth vanadate (BiVO4) is a promising photocatalytic material for use in environmental protection and water splitting. However, its short photogenerated carrier lifetime and narrow visible-light response restrict its extensive application. Herein, a novel electrospinning method was developed to prepare bismuth (Bi)-modified BiVO4 (Bi/BiVO4) porous nanofibers. The morphologies, structures, and chemical states of the obtained samples were characterized using a series of analytical techniques. The photocatalytic performance of the Bi/BiVO4 porous nanofibers was evaluated via the photocatalytic degradation of methylene blue (MB) under visible-light irradiation. The enhanced visible-light photocatalytic activity of Bi/BiVO4 can be attributed to the Bi nanoparticles, which exhibit a surface plasmon resonance (SPR) effect and have semiconductor character, extending the optical absorption of BiVO4 and restraining the recombination of electron–hole pairs during the photocatalytic degradation process, respectively. In this work, new insight is provided into the fabrication of a Bi/BiVO4 composite, which can act as an outstanding visible-light responsive photocatalyst, facilitating its application in the field of environmental protection. [ABSTRACT FROM AUTHOR]

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]

Abstract: Highly Photoluminescent (PL) carbon dots (CDs) with a PL quantum yield (PLQY) of 7.7% have been prepared from cornflour by a simple hydrothermal method. The as-prepared carbon dots have good water solubility, well distributed particle size, amorphous structure and acceptable fluorescence lifetime. Besides, due to the fairly good biocompatibility and outstanding fluorescent properties, the CDs were successfully applied to cell imaging and Cu2+ detecting. [Copyright &y& Elsevier]

Water-soluble, fluorescent carbon dots (CDs) have been successfully synthesized from waste paper. The as-prepared CDs, with an amorphous structure and small particle size, exhibit good photostability, high photoluminescence quantum yields (PLQYs) and fairly low toxicity, which indicate potential applications in the field of biolabelling. [ABSTRACT FROM AUTHOR]

Highly photoluminescent ZnSe/Au nanocomposites have been prepared via a simple low-temperature-aqueous synthesis and direct coupling approach. The mechanism of surface plasmons enhanced photoluminescence of ZnSe/Au nanocomposites is investigated. Furthermore, due to high photostability and biocompatibility, the as-prepared ZnSe/Au nanocomposites are demonstrated as excellent probes in cellular imaging. [ABSTRACT FROM AUTHOR]

• A composite with MoNi 4 alloys embedding into MoO 3-x porous nanorods was synthesized via a simple in-situ reduction method. • The obtained MoNi 4 @MoO 3-x exhibits a remarkable HER activity with 10 mA/cm2 constant current under 58.6 mV low overpotential. • The remarkable HER activity is found to originate from the MoNi 4 alloys, excellent conductivity and porous structure. [Display omitted] Hydrogen evolution reaction (HER) in alkaline media is expected to become a renewable and economical technology for hydrogen production. Various non-noble electrocatalysts have been explored for HER, in which Ni-Mo alloy is one of the best media. However, its syntheses are complicated and costly. In this work, we contribute an in-situ reduction method of porous MoNi 4 @MoO 3- x nanorods. The synthesized MoNi 4 @MoO 3- x exhibits a remarkable HER activity with 10 mA/cm2 constant current under 58.6 mV extremely low overpotential, small Tafel slope of 44.8 mV/decade, and high durability in 1 M potassium hydroxide electrolyte. Its remarkable activity is found to originate from the highly activity of MoNi 4 , excellent conductivity and favorable porous structure. This work is believed to provide a promising strategy for the HER development of highly active and cost-effective electrocatalysts. [ABSTRACT FROM AUTHOR]

[Display omitted] • 3D N, P, S-doped C-Zn 2 SiO 4 and C-MnSiO(SiO 4) are synthesized using green algaes. • C-MSi are etched by alkali to obtain abundant hierarchical pores. • e-C-MSi present excellent capacitance than C-MSi. • e-C-MSi//AC devices show good cyclic stability even after 5,000 cycles. A facile novel method of alkali etching was proposed to enhance the application of metal-silicates in supercapacitors. First, 3D N, S, P-doped C-zinc-silicate (C-ZnSi), and C-manganese-silicate (C-MnSi) were derived from calcined green algaes (GAs) in a N 2 atmosphere. Second, the synthesized products were soaked in a 3.0 M NaOH aqueous solution for alkali etching (soaked for 6, 12 and 24 h) to obtain the etching metal silicates (e-C-ZnSi and e-C-MnSi). This method can yield a higher specific surface area and more pores, and this in turn can improve the electrochemical performance. In the three-electrode system, e-C-ZnSi and e-C-MnSi, which were soaked in NaOH solution for 12 h, exhibited the highest specific capacitances and cycling performance. Solid-state hybrid supercapacitor (HSC) devices were manufactured using C-MSi, e-C-MSi (M = Zn and Mn), and activated carbon (AC) (denoted as C-MSi//AC and e-C-MSi//AC). In the two-electrode system, the e-C-MSi//AC HSC devices exhibited higher areal specific capacitances and energy densities and better cycle performance than those of C-MSi//AC, especially e-C-MSi//AC-12 h HSC devices, which exhibited the best electrochemical properties. This study demonstrated that the naturally polluted GAs can be used as a reusable silica source for the synthesis of supercapacitors. Furthermore, alkali etching can enhance the electrochemical performance of metal silicates and can be used to prepare electrode materials applied for high-performance supercapacitors. [ABSTRACT FROM AUTHOR]

The current limited and uneven distribution of lithium resources has stimulated strong motivation to develop new rechargeable batteries that use alternative charge carriers. Potassium‐based batteries are promising candidates for future large‐scale energy storage due to their low cost and high operating voltage. Here for the first time, a rechargeable K/Br battery is reported, which is assembled with a hollow carbon spheres cathode, a K metal anode, and a SOBr2 electrolyte containing AlBr3 and potassium bis‐(fluorosulfonyl)imide. The in situ formed crystalline KBr protective film during discharging plays a significant role in this system. The redox reaction between the KBr film and liquid Br2 at the cathode contributes to the main reversible capacity. K/Br battery exhibits high capacity (up to 400 mAh g‐1) and constant operating voltage (at 3.72 V vs K+/K). As a proof of concept, the K/Br battery demonstrated in this work points to a new pathway for low‐cost and next‐generation rechargeable batteries. [ABSTRACT FROM AUTHOR]

The hydrogen evolution reaction (HER) is a half-cell reaction in water electrolysis for producing hydrogen gas. In industrial water electrolysis, the HER is often conducted in alkaline media to achieve higher stability of the electrode materials. However, the kinetics of the HER in alkaline medium is slow relative to that in acid because of the low concentration of protons in the former. Under the latter conditions, the entire HER process will require additional effort to obtain protons by water dissociation near or on the catalyst surface. Heterostructured catalysts, with fascinating synergistic effects derived from their heterogeneous interfaces, can provide multiple functional sites for the overall reaction process. At present, the activity of the most active known heterostructured catalysts surpasses (platinum-based heterostructures) or approaches (noble-metal-free heterostructures) that of the commercial Pt/C catalyst under alkaline conditions, demonstrating an infusive potential to break through the bottlenecks. This review summarizes the most representative and recent heterostructured HER catalysts for alkaline medium. The basics and principles of the HER under alkaline conditions are first introduced, followed by a discussion of the latest advances in heterostructured catalysts with/without noble-metal-based heterostructures. Special focus is placed on approaches for enhancing the reaction rate by accelerating the Volmer step. This review aims to provide an overview of the current developments in alkaline HER catalysts, as well as the design principles for the future development of heterostructured nano- or micro-sized electrocatalysts. [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]

Abstract: The controlled synthesis of ZnO hierarchical structures has been successfully realized in a large scale via a simple hydrothermal method. It was demonstrated that the morphology of the final products was simply tuned by adding different amounts of soluble salt. ZnO microparticles were prepared when no soluble salt was added, whereas microspheres and nanoflowers were selectively prepared in the presence of different amounts of NaF. ZnO nanosheets were obtained when adding appropriate amount of NaCl, Na2SO4, or K2SO4. ZnO nanobelts were obtained in the presence of appropriate amount of sodium citrate (C6H5Na3O7). The photoluminescence (PL) properties of those products were researched, and the origin of the PL was discussed. [Copyright &y& Elsevier]

Ceramic matrix nanocomposites containing graphene possess superior mechanical properties. However, these nanocomposites are very difficult to be prepared using the conventional methods due to severe grain growth and simultaneous degradation of the graphene at high sintering temperatures and long dwell time. Herein, the dense ZrO2/rGO (reduced graphene oxide) nanocomposites are successfully fabricated by flash sintering of the green compacts consisting of ZrO2 nanoparticles and graphene oxide (GO) at 893–951℃ in merely 5 seconds under the alternating current (AC) electric fields of 130–150 V cm−1. The GO can be in situ thermal reduced during the flash sintering. The as‐prepared ZrO2/rGO nanocomposites exhibit excellent mechanical properties. This study presents a green and simple approach to fabricate the dense ceramic matrix nanocomposites reinforced with graphene at low temperatures in a short time. [ABSTRACT FROM AUTHOR]

Molybdenum disulfide (MoS2) nanosheets are promising candidates as earth-abundant and low-cost catalyst for hydrogen evolution reaction (HER). Nevertheless, compared with the benchmark Pt/C catalyst, the application of MoS2 nanosheets is limited to its relatively low catalytic activity, especially in alkaline environments. Here, we developed a dual-cation doping strategy to improve the alkaline HER performance of MoS2 nanosheets. The designed Ni, Co co-doped MoS2 nanosheets can promote the tandem HER steps simultaneously, thus leading to a much enhanced catalytic activity in alkaline solution. Density functional theory calculations revealed the individual roles of Ni and Co dopants in the catalytic process. The doped Ni is uncovered to be the active site for the initial water-cleaving step, while the Co dopant is conducive to the H desorbing by regulating the electronic structure of neighboring edge-S in MoS2. The synergistic effect resulted by the dual-cation doping thus facilitates the tandem HER steps, providing an effective route to raise the catalytic performance of MoS2 materials in alkaline solution. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of g-C 3 N 4 /ZnIn 2 S 4 composites were prepared by simple two-step methods. • The photocatalytic tendency of CN/ZIS samples shows "M" type with the increase of CN. • A relative p-n junction can be constructed after the combination of CN and ZIS samples. • This work mainly studies the migration direction of the photogenerated carriers. Semiconductor photocatalysis as an alternative technology has received extensive attention for addressing the worldwide energy and environment issues. However, it is still a great challenge and imperative to profoundly understand the migration mechanisms for achieving the complete utilization of photoexcited charge carriers. In this paper, a series of g-C 3 N 4 /ZnIn 2 S 4 heterojunction composites were fabricated by thermal polycondensation and solvothermal methods and then thoroughly characterized by a range of techniques. Photocatalytic selective oxidation of aromatic alcohols to corresponding aldehydes with O 2 under visible light irradiation was introduced as a model reaction system to evaluate the photocatalytic performance of the as-prepared samples. The results exhibit that when the main constituent of photocatalyst is ZnIn 2 S 4 , the transfer of the photogenerated charge carriers adopts a band-band mechanism in g-C 3 N 4 /ZnIn 2 S 4 heterojunction composite. However, when the main constituent of photocatalyst is g-C 3 N 4 , the transfer of the photogenerated charge carriers adopts a Z-scheme mechanism. Therefore, the different compositions of the composite samples lead to the different electronic conductivities and then affect the direction of the built-in electric field in the relative p-n junction, finally causing the different transfer mechanisms of the photogenerated charge carriers for g-C 3 N 4 /ZnIn 2 S 4 composite samples. [ABSTRACT FROM AUTHOR]

The Li adsorption and diffusion properties in naphyne are explored by first-principles calculations. The porous structure of naphyne facilitates the adsorption of Li atoms, and the adsorption performance of large pores is better than that of small pores. The average open circuit potential is 0.78 V and the maximum Li storage capacity of bulk naphyne is up to 620 mAh/g, much larger than the up limit of the popular graphite. Upon Li intercalation, the interlayer spacing dilatation of bulk naphyne is only 1.78 %, implying that naphyne would not undergo significant structural degradation during cycling. The average adsorption energy between Li and naphyne in LiC 3.6 is −2.38 eV/Li, which is feasible to realize their free migration. The porous structure enables Li atoms to diffuse either parallel or perpendicular to the naphyne plane. About 0.41–0.70 eV barriers are needed to overcome for the three-dimensional Li diffusion. Compared to commercial graphite, the higher Li capacity, the smaller structural distortion, and the unique three-dimensional diffusion performance of Li atoms make naphyne a promising candidate as the anode material of LIB. [Display omitted] • The highest Li storage capacity in bulk naphyne can be up to 620 mAh/g. • Upon Li embedding, the interlayer spacing dilatation of bulk naphyne is only 1.78 %. • Li is bonded to naphyne in Li+ with an average adsorption energy of −2.38 eV/Li. • The diffusion of Li atom in bulk naphyne is feasible. [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]