Two-dimensional molybdenum disulfide (2D MoS2) has drawn persistent interests as one of the most promising alternatives to Pt catalysts for the hydrogen evolution reaction (HER). It is generally accepted that the edge sites of 2D MoS2 are catalytically active but the basal planes are inert. Activating the MoS2 basal plane is an obvious strategy to enhance the HER activity of this material. However, few approaches have sought to activate the basal plane. Here, for the first time, we demonstrate that the inert basal planes can be activated via the synergistic effects of nitrogen and fluorine codoping. Our first-principles calculations reveal that nitrogen in the basal plane of the fluorine- and nitrogen-codoped MoS2 (NF-MoS2) can act as a new active and further tuneable catalytic site. The as-prepared NF-MoS2 catalyst exhibited an enormously enhanced HER activity compared to that of pure MoS2 and N-doped MoS2 due to the chemical codoping effect. This work will pave a novel pathway for enhancing the HER activity using the synergistic effects of chemical codoping.Keywords: active basal plane; electrocatalyst; fluorine and nitrogen; hydrogen evolution reaction; MoS2;

•Amorphous nickel-cobalt-boron are synthesized via a facile reduction method.•The nickel-cobalt-boron shows a high specific capacitance of 2226.96 F/g.•Ni-Co-B supercapacitor remains at 85% of its initial capacitance after 5000 cycles.Nickel-cobalt-borons are synthesized using a facile and cost-effective reduction method. The effects of Ni/Co molar ratios and crystallinity on its supercapacitive performance are systematically investigated. It was found that nickel-cobalt-borons with the Ni/Co ratio being 2:1 and amorphous structure manifest the optimum specific capacitance of 2226.96 F/g at a current density of 1 A/g and still remain 1879.2 F/g with a high discharge current density of 20 A/g. An asymmetric supercapacitor device (ASC) has been fabricated with nickel-cobalt-borons (Ni-Co-B) as the positive electrode and commercial activated carbon (CAC) as the negative electrode material. The Ni-Co-B//CAC delivers an ultrahigh energy density of 66.40 Wh/kg at a power density of 788.91 W/kg. This ASC remains 85.76% of its initial capacitance even after 5000 charge–discharge cycles. The results demonstrate that amorphous nickel-cobalt-boron material is a promising candidate for energy storage application.

•The Bac-PdNPs was prepared via a simple, green, facile and cheap method.•The synthetic mechanism of Bac-PdNPs was illuminated in detail.•The palladium nanoparticles were distributed on the surface of bacitracin uniformly.•The Bac-PdNPs possessed good stability and dispersity in KOH and C2H5OH solutions.•The composite possessed the large electrochemically active surface area.Palladium nanomaterials have attracted great attention on the development of electrocatalysts for fuel cells. Herein, we depicted a novel strategy in the synthesis of palladium nanoparticles with superior electrocatalytic activity. The new approach, based on the self-assembly of bacitracin biotemplate and palladium salt for the preparation of bacitracin-palladium nanoparticles (Bac-PdNPs), was simple, low-cost, and green. The complex, composed by a series of spherical Bac-PdNPs with a diameter of 70 nm, exhibited a chain-liked morphology in TEM and a face-centered cubic crystal structure in X-Ray diffraction and selected area electron diffraction. The palladium nanoparticles were mono-dispersed and stable in aqueous solution as shown in TEM and zeta potential. Most importantly, compared to the commercial palladium on carbon (Pd/C) catalyst (8.02 m2 g−1), the Bac-PdNPs showed a larger electrochemically active surface area (47.57 m2 g−1), which endowed the products an excellent electrocatalytic activity for ethanol oxidation in alkaline medium. The strategy in synthesis of Bac-PdNPs via biotemplate approach might light up new ideas in anode catalysts for direct ethanol fuel cells.

Rare earth doping has been widely applied in many functional nanomaterials with desirable properties and functions, which would have a significant effect on the growth process of the materials. However, the controlling strategy is limited into high concentration of lanthanide doping, which produces concentration quenching of the lanthanide ion luminescence with an increase in the Ln3+ concentration, resulting in lowering the fluorescence quantum yield of lanthanide ion. Herein, for the first time, we demonstrate simultaneous control of the structures and luminescence properties of BaCO3 nanocrystals via a small amount of Tb3+ doping strategy. In fact, Tb3+ would partially occupy Ba2+ sites, resulting in the changes to the structures of the BaCO3 nanocrystals, which is primarily determined by charge modulation, including the contributions from the surfaces of crystal nuclei and building blocks. These structurally modified nanocrystals exhibit tunable luminescence properties, thus emerging as potential candidates for photonic devices such as light-emitting diodes and color displays.We demonstrate that small amount of Tb3+ doping, mainly occupied Ba2+ sites in BaCO3 lattice, can give simultaneous control over the structures and luminescence properties of the nanocrystals, which could primarily arise from the charge modulation on the surfaces of crystal nuclei and self-assembly building blocks.Download high-res image (90KB)Download full-size image

•Treatment of semiconductor wastewater by chemical precipitation was investigated.•Removal of fluoride by Mg2+ showed good performance.•Fluoride ions exert a significant inhibitory effect on struvite crystallization.•Bittern is suitable to treat semiconductor wastewater.•PO4-P and F− can be efficiently removed using the two-stage precipitation process.This study investigates the simultaneous removal of the total ammonia nitrogen (TAN), phosphate (PO4-P) and fluoride (F−) from semiconductor wastewater by chemical precipitation. The lab-scale experiment results revealed that the fluoride removal by using magnesium salts produced a good performance. The fluoride present could significantly inhibit the struvite crystallization, in this process. The inhibition ratio of the fluoride on struvite crystallization remarkably increased with an increase in the fluoride concentration and a drop in the pH value. The optimal pH for struvite precipitation in the semiconductor wastewater was taken as 9.5, the value at which the fluoride effect significantly decreased. Therefore, to further lower the fluoride effect, an overdose of the magnesium source was required in the process of struvite precipitation. The experimental results thus indicated that overdosing the bittern was the more effective method to treat the semiconductor wastewater compared with a brucite overdose; this was because large amounts of un-reacted brucite remained in the solution, causing increased costs and operation difficulty when it was employed as magnesium source. The pilot-scale study demonstrated that 97% of the PO4-P, 58% of the TAN and 91% of the F− could be removed from semiconductor wastewater by a two-stage precipitation process. An economic analysis showed that the treatment cost of the process proposed was approximately 1.58 $/m3.Download high-res image (144KB)Download full-size image

•rGO supported MnS nanotubes (MnS-NT@rGO) hybrid was synthesized.•Nano-tubular structure endows MnS-NT@rGO high accessible surface area for ORR.•MnS-NT@rGO exhibits comparative catalytic activity for ORR to Pt/C.•MnS-NT@rGO exhibits higher activity for ORR than MnO@rGO and Mn(OH)2@rGO.•MnS-NT@rGO exhibits higher activity than rGO supported MnS nanoparticles.Electronic structure of Mn cations, electric conductivity of active materials and three dimensional structure for mass transport play vital roles in the electrocatalytic activity of Mn-based electrocatalysts for oxygen reduction reaction (ORR). To construct efficient and robust Mn-based electrocatalysts, MnS nanotubes anchored on reduced graphene oxide (MnS-NT@rGO) hybrid was synthesized and used as a novel non-precious metal electrocatalyst for ORR. The formation of nano-tubular structure, which offers more active sites and suitable channels for mass transport to enhance the electrocatalytic activity towards ORR, are carefully illustrated based on the core-dissolution/shell-recrystallization type Ostwald ripening effect. Tuned electronic structure of Mn cations, enhanced electric conductivity and suitable nano-tubular structure endow MnS-NT@rGO electrocatalyst comparative catalytic activity to commercial 20 wt % Pt/C in alkaline electrolyte. The MnS-NT@rGO electrocatalyst exhibits higher catalytic activity than rGO supported MnS nanoparticles (MnS-NP@rGO) and MnS nanotubes without rGO substrate (MnS-NT), as well as rGO supported Mn(OH)2 (Mn(OH)2@rGO) and rGO supported MnO (MnO@rGO). Moreover, the MnS-NT@rGO electrocatalyst shows superior durability and methanol tolerance to commercial Pt/C.Download high-res image (271KB)Download full-size image

•A simple and low cost biosensor was developed for detection of organophosphate pesticides.•AChE-Chitosan/Pd-Cu NWs/GCE was utilized as an effective sensing platform.•The biosensor displayed sensitive detection of malathion and the LOD was 1.5 ppt.A highly sensitive acetylcholinesterase (AChE) electrochemical biosensor for the quantitative determination of organophosphate pesticides (OPs) in vegetables and fruits based on palladium-copper nanowires (Pd-Cu NWs) was reported. AChE immobilized on the modified electrode could catalyze hydrolysis of acetylthiocholine chloride (ATCl), generating an irreversible oxidation peak. When exposed to the OPs, the activity of the AChE was inhibited and the current significantly decreased. The detection mechanism is based on the inhibition of AChE. The Pd-Cu NWs not only provide a large active surface area (0.268 ± 0.01) cm2 for the immobilization of AChE, which was approximately 3.8 times higher than the bare glass carbon electrode, but also exhibit excellent electro-catalytic activity and remarkable electron mobility. The biosensor modified with Pd-Cu NWs displayed a good affinity to ATCl and catalyzed hydrolysis of ATCl, with a low Michaelis–Menten constant (KM) of 50.56 μM. Under optimized conditions, the AChE-Cs/Pd-Cu NWs/GCE biosensor detected malathion with wide linear ranges of 5–1000 ppt and 500–3000 ppb, and the low detection limit was 1.5 ppt (4.5 pM). In addition, the OPs biosensor has been applied to the analysis of malathion in commercial vegetable and fruit samples, with excellent recoveries in the range of 98.5%–113.5%. This work provides a simple, sensitive and effective platform for biosensors and exhibits future potential in practical application for the OPs assay.Palladium-copper nanowires were employed to construct a highly sensitive acetylcholinesterase electrochemical biosensor for the quantitative determination of organophosphate pesticides in vegetables and fruits.Download high-res image (143KB)Download full-size image

Complex logic gate operations using organic microwires as signal transducers based on electrogenerated chemiluminescence (ECL) intensity as the optical readout signal have been developed by taking advantage of the unique ECL reaction between organic semiconductor 9,10-bis(phenylethynyl)anthracene (BPEA) microwires and small molecules. The BPEA microwires, prepared on cleaned-ITO substrate using a simple physical vapor transport (PVT) method, were subsequently used for construction of the ECL sensors. The developed sensor exhibits high ECL efficiency and excellent stability in the presence of co-reactant tripropylamine. Based on the remarkable detection performance of BPEA MWs/TPrA system, the sensors manifested high sensitive ECL response in a wide linear range with low detection limit for the detection of dopamine, proline or methylene blue, which behaves on the basis of molecule-responsive ECL properties based on different ECL reaction mechanisms. Inspired by this, these sensing systems can be utilized to design OR, XOR and INHIBIT logic gates, which would be used for the determination of dopamine, proline and ethylene blue via logic outputs. Importantly, the individual logic gates can be easily brought together through three-input operations to function as integrated logic gates.

Nitrogen and sulfur co-doped monodisperse carbon microspheres (NS-CMSs) have been successfully synthesized as a new kind of outstanding metal-free ORR catalyst through a one-pot solvothermal reaction. The as-synthesized heteroatom-doped CMSs have been systematically characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) and by using Raman spectra and nitrogen adsorption and desorption isotherms. Compared with the commercially available 20 wt% Pt/C catalyst, the as-prepared NS-CMSs showed a much better tolerance toward methanol crossover and long-term operation stability for ORR in an alkaline medium.

A facile method was developed for the controlled synthesis of well-defined Pd nanoparticles and nanowires, with the assistance of polyhedrin as a growth-directing agent. The concentration of polyhedrin plays a key role in the final morphology. The cyclic voltammetry and current–time tests demonstrate that the Pd samples show vastly superior electrocatalytic properties compared to the commercial Pd/C catalysts. Moreover, the Pd supported by carbon black or multi-wall carbon nanotube exhibits significantly enhanced electrocatalytic activity toward ethanol oxidation, indicating a great potential for application in fuel cells.

The synthesis of ultrathin single-crystal 1D (one dimensional) nanostructures is highly desirable for potential applications as nanoconnectors and nanoscale devices. In this work, we demonstrate the preparation of straight single-crystalline coaxial silver nanocables (13 nm core diameter, 1.5 nm sheath thickness) in large amounts with excellent dispersibility for the first time through a self assembly approach via insulin fibril templates. This outstanding method for obtaining silver nanocables with ultrathin diameters will be attractive for the fabrication of other metallic 1D nanostructures, and this study may offer an effective strategy to design a novel silver nanostructure with diverse functionalities and potential applications in conductive materials, sensors and catalysts.

In this study, the self-assembly of platinum nanoshells (PtNSs) in facile conditions, using the adenovirus shuttle vector-GFP (Adv) as a biotemplate, was achieved. This novel and simple biotemplating method can be summarized as direct co-incubation of the template Adv and PtCl4 solution, followed by the reduction of the co-incubation solution using NaBH4. The prepared Adv–PtNSs were then characterized by TEM, XRD and FTIR. The TEM results indicated that Adv–PtNSs, with good morphologies and monodispersity, can be obtained by controlling the concentration of PtCl4 as 7.5 mM, and the obtained Adv–PtNSs were about 100 nm. The results of XRD and FITR demonstrated that the prepared Adv–PtNSs were in a face-centered cubic structure, and the combination between the Adv and platinum complex ions mainly depended on –NH groups. In addition, the biocompatibilities of the prepared Adv–PtNSs to H9c2 cells were investigated. MTT assay results showed that as-prepared Adv–PtNSs had relatively high biocompatibilities, and caused almost no harm to H9c2 cells. Therefore, Adv–PtNSs have great potential as bioelectrode materials for monitoring the states of organisms.

A novel biotemplating method for fabricating gold nanoshells (AuNSs) through direct co-incubation of AuCl3 solution and an adenovirus shuttle vector-GFP (Adv) template in water, followed by the reduction of the mixture using fresh NaBH4, has been investigated in this paper. For comparison, different adenovirus-templated gold nanoshells (Adv-AuNSs) were prepared by modifying Adv with chitosan or changing the ionic conditions of the reaction system. The morphology and structure of the prepared AuNSs were characterized using transmission electron microscopy (TEM) and X-ray diffraction (XRD). The result indicated that Adv-AuNSs prepared by co-incubation of naked Adv and 7.5 mM AuCl3 solution had a uniform structure of approximately 120 nm diameter and face-centered cubic (fcc) crystal structure in the XRD pattern. A study of the biocompatibility of the prepared Adv-AuNSs demonstrated that there was no significant cytotoxicity. In addition, the photothermal therapy efficacy of the Adv-AuNSs on tumor cells was investigated in detail, revealing that all tumor cells could be killed when the power of near-infrared light irradiation was 4 W cm−2. Therefore, the prepared Adv-AuNSs will have very promising applications in the photothermal therapy of tumors.

Platinum nanoparticles (PtNPs) were assembled in a chain-like structure by activating chemical groups of the octreotide acetate (AOC) template. Tumor-bearing mice were inoculated with cervical carcinoma cells, and then treated with a low dose of AOC-PtNPs (AOC-PtNPs-L), a high dose of AOC-PtNPs (AOC-PtNPs-H), sterile physiological saline and cyclophosphamide. The results suggested that tumor inhibition rates of cyclophosphamide, AOC-PtNPs-L and AOC-PtNPs-H were 87.0%, 38.3% and 42.5%; and the apoptosis rates of the tumor-bearing mice were 30.95%, 23.41% and 26.64%, respectively. More importantly, the histopathological study results implied that AOC-PtNPs had no toxicity or side-effects on liver and kidney tissues, but obvious inhibitory effects on tumors. In addition, MTT assay results showed that the as-prepared AOC-PtNPs had a higher inhibition rate on Hela cells than that of AOC or PtNPs alone. Therefore, AOC-PtNPs have great potential as anti-tumor drugs for cancer therapy in the future.

La2NiCrO6, previously proposed to be a candidate of half metallic antiferromagnetism, is revisited using the first-principles calculation. Electron correlation is considered and cation ordering effects are studied by arranging Ni and Cr atoms along [111] and [001]. For the [111] case, which corresponds to an ordered double perovskite, a monoclinic structure is predicted to be the most stable. In contrast to the previous study, it is insulating from the calculation of electron structure. Attractively, the magnetic coupling of Ni and Cr is sensitive to electron correlation, i.e., it is antiferromagnetic in the GGA calculation, whereas the ferromagnetic state is favoured when electron correlation (U) is turned on. For the [001] case, it is ferromagnetic whether U is included or not. Interestingly, a semiconductor to half metal transition is expected according to the GGA + U method, and the half metallic character could be preserved under both compressive and tensile strain.

Combining first-principles calculations and quantitative predictions of a semiempirical hardness theory developed recently, we show that 6H diamond (6H-C), a representative of noncubic polymorphs of carbon can be harder than a cubic diamond. Such eminently high intrinsic hardness exceeding that of diamond is identified theoretically for the first time. The results challenge the conventional wisdom that cubic diamond is the hardest single crystal.

•A simple approach was developed to synthesize Sn doped Mn3O4/C nanocomposite.•The potential application as supercapacitor electrode was tested.•The as-synthesized nanocomposite shows excellent rate capability and cycling stability.•A ~93% capacitance retention after 10,000 charge/discharge cycles was achieved.Sn-doped Mn3O4/C nanocomposite was synthesized using Pluronics P123 (EO20PO70EO20) as both structure-directing agent and carbon source. The phase and morphology was characterized with X-ray diffraction (XRD), X-ray spectroscopy (EDS), Field-emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The electrochemical performance of the sample was tested in 6 M KOH A high specific capacitance of 216 F g−1 was achieved at current density of 5 A g−1, and 93% capacitance retention remained after 10,000 charge/discharge cycles.

By means of first-principles calculations based on density functional theory (DFT) and hybrid functional, we studied the structural, electronic, and ferroelectric properties of the two recently synthesized high-pressure perovskite-type (orthorhombic, space group Pnma) and LiNbO3-type (rhombohedral, space group R3c) polymorphs of CdPbO3. Besides providing structural and electronic results in good agreement with available experiments, our results are able to correctly describe the pressure-induced Pnma → R3c structural phase transition and most importantly predict the realization of proper ferroelectric behavior in LiNbO3-type CdPbO3 with an electric polarization of 52.3 μC/cm2. The proper covalent interaction mechanism driving the ferroelectric transition is discussed and explained in terms of the analysis of Born effective charges, potential-energy surfaces, charge density isosurfaces, and electric localization function.

•LiNiCuZn oxide with hierarchical porous structure was synthesized.•The potential application in SOFC is tested.•An artemia cyst shell was applied as the natural biotemplate.Low temperature, 300–600 °C solid oxide fuel cell (LTSOFC) is one of the hot areas in recent fuel cell development. In order to develop high performance LTSOFCs, compatible electrodes are highly demanded. In this work, a lithium transition metal oxide electrode material with hierarchical porous structure was synthesized. The phase structure was analysed by XRD and microstructure was studied by SEM. The as-synthesized material was constructed to devices using the SDC (samarium doped ceria)-carbonate nanocomposite (NSDC) as the electrolyte to test the OCV (open circuit voltage), which indicates good catalytic performance for H2 at 600 °C.

In this paper we report that ZnS nanoparticle wires were synthesized by using DNA template for the first time with a simple precipitation method under mild conditions. The diameter of the synthesized ZnS nanoparticle wires was about 15–35 nm and the diameter of ZnS nanoparticles was in the range of 4–9 nm as characterized by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). Zinc blende structure was established by selected area electron diffraction (SAED) and X-ray diffraction (XRD) characterization. The optical properties were investigated by ultraviolet–visible (UV–vis) absorption spectrum, which shows a blue-shift in absorption peak as compared to that of bulk ZnS due to quantum confinement effects. The particle size from TEM is in good agreement with the result calculated from the UV–vis absorption spectra and the chemical bond theory built for semiconductor nanocrystals. Photoluminescence (PL) spectrum of ZnS nanoparticle wires shows that there are two blue emission peaks at 411 nm and 437 nm, which may be ascribed to the sulfur vacancies and interstitial sulfur lattice defects respectively.Highlights► First realization of ZnS nanoparticle wires by attaching ZnS nanocrystals to DNA molecular skeleton by a simple precipitation method under mild conditions. ► The UV–vis absorption spectrum was used to track the reaction process of this experiment. ► The UV–vis absorption spectrum shows a blue-shift of absorption peak as compared to bulk ZnS due to quantum confinement effects. ► PL spectrum shows two blue emission peaks at 411 nm and 437 nm.

•The synthesis of Pt nanowires (PtNWS) with diameter range from 15–20 nm, length to micrometers were performed using α-chymotrpsin amyloid fibrils (α-CTAFS) as a sacrificial template.•Results indicated that DMAB was a facile and good reducing agent to fabricate PtNWS.•Electrochemical measurement methods are used to study the properties of the as prepared PtNWSPt nanoparticle chains (PtNPCS) with diameter ranging from 15–20 nm and length to micrometers were fabricated using α-chymotrpsin amyloid fibrils (α-CTAFS) as a sacrificial template. The PtNPCs can be simply obtained by reducing the salt precursors using two different reducing agents, borane-dimethyl-amine complex (DMAB) and sodium borohydride (NaBH4), in aqueous environment. Electrochemical measurements were used to study the properties of the PtNPCs that achieved from different reducing ways. Results indicates that DMAB is a facile reducing agent to prepare PtNPCs with a more uniform particle size and higher catalytic activity on methanol oxidation (MOR) and oxygen reduction reaction (ORR) than that obtained by using NaBH4 as reductant.

•PbS nanophere chains structure was synthesized by using DNA template with a simple precipitation method under mild conditions.•Photoluminescence (PL) spectrum of PbS nanophere chains showed there were two emission peaks respectively at 324 nm and 360 nm.•The formation mechanism of PbS nanosphere chains have been proposed in this article.In this work the unique PbS nanosphere chains were synthesized by using DNA template with a simple precipitation method under mild conditions. The average diameter of the synthesized PbS nanospheres is about 30 nm as characterized by transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS). Cubic galena structure was confirmed by selected area electron diffraction (SAED) and X-ray diffraction (XRD) characterizations. Photoluminescence (PL) spectrum of PbS nanosphere chains showed that there were two emission peaks at 324 nm and 360 nm, respectively. The formation mechanism of PbS nanosphere chains was also proposed.Schematic illustration of the formation of PbS nanosphere chains.

•InP nanowires have been synthesized by employing chemical vapor deposition method.•The structure and morphology of the products have been fully characterized.•The possible growth mechanism of the InP nanowires is briefly discussed.One-dimensional III - V semiconductor nanostructures have attracted much attention due to their novel electrical and optical properties. In this work, InP semiconductor nanowires have been successfully synthesized by employing chemical vapor deposition method using In powder and red phosphorus as precursors. The morphology and structure of the products have been characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and energy dispersive spectroscopy (EDS). Cubic sphalerite structure of InP nanowires was established by selected area electron diffraction (SAED) and X-ray diffraction (XRD) characterization. The possible growth mechanism of the InP nanowires with stacking faults structures is briefly discussed.

First-principle calculations of the structural, electronic, vibrational and mechanical properties of the primitive-centered tetragonal boron nitride (pct-BN) structure are performed. Results reveal that pct-BN is more energetically favorable than h-BN above the pressure of 8.8 GPa and dynamically stable at up to 120 GPa. Electronic bonding indicates that pct-BN possesses a covalent character with near-tetrahedral sp3-hybridized electronic states. Vibrational property calculations show that its characteristic sp3 Raman peaks are at 738 cm−1, 1032 cm−1 and 1155 cm−1. The mechanical failure mode of pct-BN is dominated by the shear type. The lowest peak stress of 43.1 GPa under (110) [10] shear sets an upper bound for its ideal strength. The calculated minimum hardness of pct-BN is greater than that of w-BN. Its average hardness approached that of c-BN, indicating that this novel BN allotrope is a potential superhard material.

We reported a facile method for preparing self-assembly gold nanochains by using insulin fibrils as biotemplate in aqueous environment. The gold nanochains hybrid nanostructures, which are insulin fibrils coated by gold nanoparticles, can be fabricated by simply reducing the salt precursors using DMAB. By increasing the molar ratio between salt precursors and insulin, denser hybrid nanochains can be obtained, meanwhile the mean diameter of gold nanoparticles is changing from 8 to 10 nm and then to 12 nm. The fabricated gold nanochains hybrid had helix structure, which was confirmed by circular dichroism spectra. The hybrid nanostructures were also investigated by transmission electron microscope, atomic force microscope, Fourier transform infrared spectra, and UV–Visible spectroscopy. As the wire-like structure become denser, the suspensions show color-changing, corresponding to the surface plasmon resonance red shift, which is attributed to the increasing mean size of nanoparticles. Based on the characterizations, a hypothetic mechanism was suggested to describe the formation processing of hybrid gold nanochains.

Antireflective coatings (ARCs) on tri-layer thin film stacks were studied in this paper. Silica sols have been prepared by acid-catalyzed or base-catalyzed hydrolysis and condensation reactions of tetraethyl orthosilicate. Antireflective nanometric SiO2/TiO2 films are formed on both sides of the glass substrates by combining the sol–gel method and the dip-coating technique. Seen from the transmittance spectra of different films, a maximum light transmittance of 99.9% was obtained at the band of 300–800 nm. Scanning electron microscope (SEM) and atomic force microscopy (AFM) confirm the well-covered surface morphology. By the SEM observations we can see that the films are full of coverage on glass surface and containing no voids or cracks. The image root mean square roughness of the two types of ARCs provided by the AFM is 1.21 and 3.04 nm, respectively. Furthermore, a surface profiler was used to determine the thickness of each layer in the obtained multi-layer coating system.

Through a facile solvothermal method, the controlled preparation of ZnS nanocrystals with different phases and morphologies was achieved only by changing the organic additives. By adding the surfactant of sodium dodecyl benzene sulfonate (SDBS) into the reaction, the cubic heart-like ZnS nanoparticles with uniform size were obtained in a large scale. While, with the assistance of the biomolecule of alginic acid, the pure phase of hexagonal ZnS nanospheres assembled from small ZnS nanoparticles were synthesized. The optical properties of the obtained ZnS nanocrystals were investigated by ultraviolet–visible (UV–vis) absorption and photoluminescence (PL) spectra. The quantum confinement effect could be observed clearly in ZnS nanoparticles.

Growth and assembly of inorganic materials with the guidance of biomolecules is a promising route to control over the arrangement of nanoparticles. We present in this article an effective and efficient method for producing zinc oxide (ZnO) nanoparticle chains by directly using DNA as guide. Using extensive experiments over a wide range of synthesis parameters, such as the solvents and the concentrations of reactants, we have obtained high-quality ZnO nanoparticle chains in different sizes. This strategy makes it possible to tailor the optical and structural properties of ZnO nanoparticles aggregated on DNA. We have also studied theoretically the variation of the bandgap energy with the size of the ZnO nanocrystals using a chemical bond theory of quantum size effects. Furthermore, possible mechanisms are discussed in detail.

Size dependence effects in semiconductor clusters have been a subject of extensive studies for the last two decades. However, it is still difficult to employ the existing theoretical models to give reliable results of energies for clusters in the whole nanometer region. Here we offer a new theoretical method for the quantum size effects based on the idea that the energy gap shift of the cluster arises from the sum of the surface effect shift and quantum effect shift parts. We express the effects through algebraic relations rather than through variational solutions of the wave equation, without the use of any special adjustable parameter. Results reveal for the first time that the shape of the energy gap shift curve is dominated by the surface energy shift. Our method can also predict quantitatively the size dependence of dielectric constant. The new theoretical findings in the ultrasmall (<1 nm) anatase TiO2 and the silicon clusters cannot be explained using previous theories.

First principles calculations were performed to study the hardness, electronic and elastic properties of lanthanide nitrides in rocksalt structure. The calculated lattice parameters are in good agreement with experimental and other theoretical values. The calculations indicate that NdN, PmN, SmN, EuN, TbN are mechanically unstable. The lower B/G and Poisson's ratio of HoN and ErN show that they are brittle than other lanthanide nitrides. Results reveal that the ligand field stabilization energy and lanthanide contraction play important roles in determining the hardness of lanthanide nitrides in rocksalt structure.

Hexagonal gallium nitride nanowires were synthesized successfully by solvothermal method with alginate as template. The microstructure, morphologies and compositions of the as-prepared product were characterized by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), selected area electron diffraction (SAED), high resolution transmission electron microscopy (HRTEM), and energy dispersive X-ray (EDX). Results suggested that the rod-like nanowires were hexagonal single-crystalline GaN growing along [001] direction. The photoluminescence spectra (PL) of the GaN revealed that the as-synthesized sample possesses excellent optical properties.

Confining the growth of inorganic materials in patterns using DNA as a molecular guide represents a versatile system for nanoscale construction. Here, we report the first example of efficiently attaching BaWO4 nanocrystals to dsDNA skeleton forming in patterns of well-defined nano pair-linear arrays. We have studied the influences of solution temperatures and concentrations of reagents on the pair-linear morphology. Results indicate that the two factors play the important roles in synthesizing the stable and desired patterned pair-linear arrays. We have tested four kinds of oligonucleotides to investigate systematically how nucleotide functionalities influence nanoparticle growth. We find that the phosphate and possibly the amino moiety binding site on adenine are the favorable targets to feed nanoparticle growth. On the basis of our findings, possible mechanisms are discussed.

The structural stability and elastic and electronic properties of rhenium borides with different boron concentration are calculated systemically by means of first principle total energy calculations. The total energy calculations reveal that the WC-type structure is more energetically favorable for ReB and that the Re2P-type structure is more preferred for Re2B. The formation enthalpy of these borides have been studied by the solid synthesis routes. The calculated elastic properties indicate that Re2B3, ReB, and Re2B phases are also potential hard materials. Although valence-electron density was often employed to evaluate elastic properties of materials, our calculations indicate that the bulk elastic properties of these borides are not direct correlation with their valence-electron density. The analysis of electronic structure, charge density distribution, and Mulliken overlap population provides further understanding of the elastic and superconductivity properties of these borides.

Single-crystalline B-C-N nanorods were prepared at 500 °C and less than about 20 MPa. Results from X-ray powder diffraction (XRD) and selected-area electron diffraction (SAED) measurements suggest that the synthesized single-crystalline B-C-N is of tetragonal structure and its lattice constants are a = 7.12(5) Å and c = 3.57(3) Å. The nanorods all are very straight, and the ratios of length to diameter are between 5 and 30. High resolution transmission electron microscopy (HRTEM) and scanning electron microscopy (SEM) observations confirm the well-defined nanorods grown preferentially perpendicular to the [220] direction develop tetragonal morphologies. The energy-loss spectroscopy (EELS) and energy-dispersive X-ray (EDX) elemental mapping confirm that the nanorod is composed of B, C, N, and a trace of oxygen, and its stoichiometry is determined to be close to BC 2N. First-principles calculations confirm that the as-prepared sample is superlattice phase of β-BC 2N phase with defects of the C N′ and the O N′. In addition, it is a semiconductor material with a direct energy band gap 1.21 eV. The calculated hardness is comparable to that of diamond.

Highly uniform single-crystal ultrathin Pt nanowires (UTPtNWs) with a diameter of ∼1.8 nm and a superhigh aspect ratio of >104 were fabricated using insulin amyloid fibrils (INSAFs) as sacrificial templates. The use of INSAFs to build the UTPtNWs allowed for the preferential exposure of low-energy crystal facets that would be highly advantageous for the methanol oxidation reaction. The UTPtNWs displayed a large electrochemical active surface area of 71.34 m2/g, which is much higher than that of a commercial Pt/C catalyst. The UTPtNWs also maintained excellent electrochemical durability under repeated cyclic voltammetry scans. Because of its exciting high electrochemical activity, UTPtNWs is a promising material for the design of next-generation electrocatalysts and would also be useful in sensing, biomedical, and other electrochemical applications.

Nitrogen and sulfur co-doped monodisperse carbon microspheres (NS-CMSs) have been successfully synthesized as a new kind of outstanding metal-free ORR catalyst through a one-pot solvothermal reaction. The as-synthesized heteroatom-doped CMSs have been systematically characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) and by using Raman spectra and nitrogen adsorption and desorption isotherms. Compared with the commercially available 20 wt% Pt/C catalyst, the as-prepared NS-CMSs showed a much better tolerance toward methanol crossover and long-term operation stability for ORR in an alkaline medium.

First-principle calculations of the structural, electronic, vibrational and mechanical properties of the primitive-centered tetragonal boron nitride (pct-BN) structure are performed. Results reveal that pct-BN is more energetically favorable than h-BN above the pressure of 8.8 GPa and dynamically stable at up to 120 GPa. Electronic bonding indicates that pct-BN possesses a covalent character with near-tetrahedral sp3-hybridized electronic states. Vibrational property calculations show that its characteristic sp3 Raman peaks are at 738 cm−1, 1032 cm−1 and 1155 cm−1. The mechanical failure mode of pct-BN is dominated by the shear type. The lowest peak stress of 43.1 GPa under (110) [10] shear sets an upper bound for its ideal strength. The calculated minimum hardness of pct-BN is greater than that of w-BN. Its average hardness approached that of c-BN, indicating that this novel BN allotrope is a potential superhard material.