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Nanostructured silicon carbide (SiC) materials are expected to have bright prospect in application as high-performance electrode materials with excellent charge–discharge cycling stability. However, the exploration of SiC-based micro-supercapacitors (MSCs) still remains a grand challenge seriously hampered by low areal capacities and complicated multistep production process. Herein, we report that rationally designed SiC/C nanocomposite with hierarchical porous structure and improved electrical conductivity has been realized by a facile and rapid carbothermic reduction using silica sol and sucrose as silicon and carbon source. The amorphous carbon between SiC nanoparticles (NPs) contributes to enlarged surface areas and excellent conductivity, not only ensuring intimate contact between the electrolyte and the electrode but also providing an effective ion highway for electrolyte ions. As a result, MSCs based on SiC/C nanocomposite (Si/C mass ratio of 1:1.5) demonstrate an optimal specific areal capacitance of 11.8 mF cm−2 at 2 mV s−1, outstanding flexibility (104.5% retention of initial capacitance at 180° bending), and superior integration. Most notably, the capacitance remains at 97.3% of the initial value after 50000 charging/discharging cycles, superior to that of most advanced SiC-based MSCs ever reported. This work demonstrates an effective design for hierarchical porous SiC/C nanocomposite for energy storage, which gives significant inspirations on the exploration of high-performance SiC-based MSCs.

GeP3 materials are attracting broad research interest due to their typical puckered layer structure, high carrier mobility, and chemical stability. This peculiarity expedites the independent control of anisotropic electrical and thermal conductance, which is thus expected to possess great thermoelectric potential. Nevertheless, the metal characteristics of GeP3 in the bulk and thick films are adverse to real application because of the low Seebeck coefficient. Thus, it is highly desirable to explore effective solutions to broaden the band gap and also maintain its excellent electrical conductance. Herein, we designed the interlaced GeP3/hexagonal boron nitride (h-BN) bulk heterostructure using various component thicknesses. By using ab initio calculations based on the Boltzmann transport theory, we found that capping h-BN layer can obviously increase the band gap of the GeP3 layer by 0.24 eV, and more interestingly, the anisotropic electronic structure in the GeP3/h-BN heterostructure was accordingly modulated toward a favorable direction for high thermoelectricity. An ultrahigh ZT value of around 5 was predicted at 300 K in p-type GeP3/h-BN, attributed to the adjusted multivalley band structure. Overall, our work provided an effective route to design novel high-performance thermoelectrics through the appropriate construction of heterostructures.

It is of great significance to improve the tribological performances of self-lubricating system to reduce the exfoliation of abrasive particles. In this work, tribological performances of Si3N4–PTFE–EP self-lubricating composites with surface-modified micro/nano-Si3N4 (20 nm, 100 nm, 500 nm, 1–3 μm, and 10 μm) prepared by high-pressure (3 GPa) compression molding are investigated systematically. The results show that although the surface modification of nano-Si3N4 can improve tribological performances of Si3N4–PTFE–EP composite, Si3N4 particle size is the more critical factor. When Si3N4 particle size is 10 μm, the tribological performances of 70M–Si3N4–30PTFE–EP, 50M–Si3N4–50PTFE–EP, and 30M–Si3N4–70PTFE–EP composites are optimal.

The tribological performance of ceramic–polymer composites prepared by high-pressure (3 GPa) compression molding of silicon nitride (Si3N4) and polytetrafluoroethylene (PTFE) with epoxy resin (EP) ...

A series of excellent works have demonstrated that high-nitrogen-content metal pentazolate (cyclo-N5–) compounds could be stabilized by high pressure. However, under ambient conditions, low stability precludes their synthesis and application in the field of high-energy-density material. In this work, by using a constrained structure search method, we predicted two new structures as P212121-CuN5 and P21/c-CuN5 containing cyclo-N5– with strong N–N and Cu–N bonds. In both structures, cyclo-N5– form four coordination with the Cu+ ligand, which increases the structural stability by lowering the disturbance to the aromaticity of cyclo-N5–. The calculated results show that the P212121-CuN5 and P21/c-CuN5 structures exhibit high dynamic and thermal stability up to 400 K, indicating that they can be stabilized under ambient conditions. The decomposing energy of P212121-CuN5 and P21/c-CuN5 can reach up to 2.40 and 2.42 kJ/g, respectively. Strikingly, the detonation velocity and the pressure of P212121-CuN5 is predicted to be up to 10.42 km/s and 617.46 kbar, respectively, indicating that they are promising high-energy candidates in the field of explosive combustion.

Polycrystalline diamond with high mechanical properties and excellent thermal stability plays an important role in industry and materials science. However, the increased inherent brittle strength with the increase of hardness has severely limited its further widespread application. In this work, we produced well-sintered nano-polycrystalline (np) diamond by directly sintering fine diamond powders with the boron carbide (B4C) additive at high pressure and high temperatures. The highest hardness value of up to ∼90 GPa was observed in the np-diamond (consisting of fine grains with a size of 16 nm) by adding 5 wt% B4C at 18 GPa and 2237 K. Moreover, our results reveal that the produced samples have shown noticeably enhanced strength and toughness (18.37 MPa m0.5) with the assistance of the soft phase at the grain boundaries, higher than that of the hardest known nano-twined diamond by ∼24% and a little greater than that of the toughest CVD diamond (18 MPa m0.5). This study offers a novel functional approach in improving and controlling the hardness and stiffness of polycrystalline diamond.

Two-dimensional (2D) layered bismuth (Bi) with a thickness-dependent direct bandgap (0–0.55 eV) has attracted ever-increasing research interest in electronics, energy storage and conversion devices. However, few-layer Bi nanosheets (NSs) are easily oxidized under ambient conditions. Searching for a convenient and low-cost strategy to produce high-quality few-layer NSs in large scale is of great importance to prompt its practical applications. Herein we report that the liquid-phase exfoliation method with acetone solvent is suitable for fabricating 2D thin and low-oxidized Bi NSs. Next, we assemble the produced Bi NSs into all-solid-state supercapacitors (ASSPs). The as-prepared devices exhibit a volumetric capacitance of 36.8 F cm−3, together with excellent volumetric energy and power densities. The volumetric capacity can be further enhanced up to 68.7 F cm−3 by compositing with CNTs. The maximum volumetric energy and power densities are 9.5 mW h cm−3 and 203.2 W cm−3, respectively. Moreover, we demonstrate that the Bi/CNT devices exhibit outstanding flexibility (79.0% retention of the initial capacitance at 180° bending) and superior cycling stability (82.2% retention of the initial capacitance after 20 000 cycles), demonstrating the great potential of Bi/CNTs for high-performance flexible ASSPs.

Recent discoveries in high pressure science have revealed entirely unexpected chemical behavior of two-dimensional (2D) materials. However, there is still a lack of unambiguous insight on the pressure-driven behavior of in-plane bonds in the 2D layered structures. Layered germanium phosphide (GeP5) is a metal with honeycomb-like sheets structurally similar to semiconducting black phosphorous, but with electrical conductivity ten times higher than that of graphite. Here, we report a remarkable pressure-dependent structural transformation that includes lengthening of the main in-plane bonds under pressure, although practically high pressure usually leads to shorter stiffer bonds. In situ Raman measurements show that there is significant phonon mode softening through the 2D–3D structural reconstruction, correlating with the in-plane bond extensions in GeP5 upon compression. This is accompanied by unusually superconducting behavior, on both sides of the transformation. This superconductivity with a maximum transition value of 10.5 K at 13.5 GPa shows a robust character without obvious reduction up to 60 GPa and is accompanied by pressure-induced amorphization in GeP5. Our experimental results, together with those from first principles calculations, not only provide the detailed high-pressure phase diagram of GeP5 but also connect the pressure-dependent bond extension with enhanced superconductivity.

BeN10 has the highest nitrogen mass concentration (up to 94%) around metal pentazolates. However, it is still a challenge to directly confirm the microstructure and property of the most stable BeN10 under ambient conditions due to the metastable feature of energetic materials. In the present study, we directly detected a new BeN10 crystalline structure under atmospheric pressure by a constrained crystal structure search method. In comparison with the phase searched from high pressures, this new BeN10 shows much lower formation energy (1.37 eV per formula). Its dynamic and thermodynamic stabilities were further evaluated via phonon spectrum simulations and molecular dynamics simulations, and the calculated results show that this new BeN10 salt has good stability up to 600 K. The bond analysis indicates that the bond strength of Be–N is a key factor to stabilize BeN10. Moreover, the simulations of electronic structures and the absorption spectrum indicate that this new BeN10 salt is an intrinsic insulator along with good optical stability. The oxidative decomposition of the BeN10 salt could release energy up to 5.36 kJ g−1, which indicates that BeN10 is a kind of potential excellent energetic material.

Twist-angle two-dimensional (2D) systems are attractive in their exotic and tunable properties by the formation of the moiré superlattices, allowing easy access to manipulating intrinsic electrical and thermal properties. Here, the angle-dependent thermoelectric properties of twisted bilayer black phosphorene (tbBP) by first-principles calculations are reported. The simulations show that significantly enhanced Seebeck coefficient and power factor can be achieved in p-type tbBP due to merging of the multi-valley electronic states and flat moiré bands. Moreover, the twisted layers bring in a strong anharmonic phonon scattering and thus very low lattice thermal conductivity of 4.51 W m

Recently, it has been reported that high-pressure synthesized lithium pentazolates could be quenched down to ambient conditions. However, the crystalline structures of LiN5 under ambient conditions are still ambiguous. In this work, the structures of LiN5 compound were directly explored at atmospheric pressure by using a new constrain structure search method. By using this method, three new allotropes were confirmed, and they show lower energy than the previous reported LiN5 phases. Both their thermodynamic and dynamic stability were confirmed through formation enthalpies, phonon spectrum, and ab initio molecular dynamics simulations under ambient conditions. Moreover, these three allotropes show similar formation enthalpies and properties, which suggests that it is hard to obtain a single LiN5 phase, which is well consistent with the experimental phenomenon. Furthermore, because of their low formation energy, all of them possess low energy density when they directly decompose to Li3N and nitrogen (0.52 kJ/g). Instead, the decomposed energy could be further improved to 3.78 kJ/g when they decompose under an oxygen-rich environment.

Two-dimensional (2D) layered magnetic materials have attracted great attention in recent years because of the discovery of long-range order of magnetism down to the monolayer and its expected appli...

Based on ab initio density functional theory calculations and by using the global optimization algorithm, we propose a novel two-dimensional (2D) InP3 allotrope (δ-InP3 monolayer), which has much lower formation energy and exfoliation energy than those of the earlier known β-InP3 monolayers. The δ-InP3 monolayer has an indirect bandgap of 0.51 eV, which could be easily tunable by adjusting the strains along the a direction. Our calculations reveal that this new InP3 allotrope exhibits worthwhile anisotropy along with high electron carrier mobility. The electron mobility of the δ-InP3 monolayer can reach up to 2741 and 1751 cm2 V−1 s−1 along the a and b directions, respectively. The absorption coefficients for the δ-InP3 monolayer and bilayer are predicted up to the order of ∼106 cm−1 in the entire visible region. More interestingly, the calculated results show that the δ-InP3 monolayer is a promising N-based gas sensor (particularly for NO2 molecules), with high selectivity, sensitivity, and good reversibility.

Black phosphorus (BP) has drawn great attention owing to its tunable band gap depending on thickness, high mobility, and large Ion/Ioff ratio, which makes BP attractive for using in future two-dimensional electronic and optoelectronic devices. However, its instability under ambient conditions poses challenge to the research and limits its practical applications. In this work, we present a feasible approach to suppress the degradation of BP by sulfur (S) doping. The fabricated S-doped BP few-layer field-effect transistors (FETs) show more stable transistor performance under ambient conditions. After exposing to air for 21 days, the charge-carrier mobility of a representative S-doped BP FETs device decreases from 607 to 470 cm2 V–1 s–1 (remained as high as 77.4%) under ambient conditions and a large Ion/Ioff ratio of ∼103 is still retained. The atomic force microscopy analysis, including surface morphology, thickness, and roughness, also indicates the lower degradation rate of S-doped BP compared to BP. Fir...

In this study, high quality GeP5 crystals with two-dimensional (2D) layered structures and novel electrical conductivity of 2.4 × 106 S m−1 have been prepared under high-temperature high-pressure oriented growth technique (HTHP-OGT). The as-synthesized GeP5 nanoflakes, after liquid phase exfoliation, show promising potential for application as electrode materials in all-solid-state supercapacitors (ASSPs). The as-prepared GeP5-ASSP exhibits excellent electrochemical performances, including an ultrahigh scan rate of 1000 V s−1, a high specific capacitance of up to 35.86 F cm−3 at 5 mV s−1, a great power density of 397.24 W cm−3 and an energy density of 4.98 mW h cm−3. Moreover, the device can retain 83.7% and 88% of the initial capacitance retention at 180° bending and after 10 000 cycles, respectively, showing outstanding flexibility and superior cycling stability. These properties indicate the promising application of the metallic layered GeP5 for flexible energy storage devices.

Dirac materials have received attracting attentions due to their intriguing properties and potential applications in advanced electronics. In this work, we reported 44 new two-dimensional Dirac materials, named ABX6 monolayers, by constructing group IVA, VA, and VIA elements with the same structural prototype. Our first principle calculations revealed that they show excellent dynamical stability, mechanical stability, and thermodynamics stability. Those monolayers possess the elastic constant from 23.93 to 245.57 N/m, attributing to broadly used mechanical strength materials. The electronic calculations show that the Dirac cones in all ABX6 monolayers are both located at K points in Brillouin zone and mainly contributed from the pz orbital of group IVA atoms and group VIA atoms. Their Fermi velocities are from 3.44 × 105 to 6.83 × 105 m/s, which is benefiting for the potential applications in high-speed electric devices. Moreover, it is interesting to notice that the ABX6 monolayers with heavy atoms, such as the ISbSn6 monolayer, exhibit a large band gap of ∼ 0.106 eV, due to the spin-orbital coupling effect. The further calculations reveal their nontrivial topological nature with topological edge states, indicating they could be used as potential dissipationless transport devices at room temperature.

The ω-zirconium (ω-Zr) is generally considered as the favorable strengthening phase in the application of Zr and its alloys. However, the intrinsic mechanism is still unclear. In this study, the elastic constants and anisotropic ideal shear strengths of ω-Zr and the common α-Zr phase are systematically studied by the first-principle calculations. Results reveal that the shear modulus of ω-Zr is 1.37 times that of α-Zr. The lowest shear strength of ω-Zr is 3.25 GPa along ( 1 0 1 ¯ 0 ) [ 0 0 0 1 ] , which is about 1.6 times the weakest shear strength (2.01 GPa) of α-Zr along ( 1 0 1 ¯ 0 ) [ 1 ¯ 2 1 ¯ 0 ] . In addition to the high strength, the critical strain of ω-Zr is 0.173, much larger than that (0.072) of α-Zr. The electron localization function (ELF) result shows that there are more electrons highly localized in ω-Zr than in α-Zr along their weakest shear directions, indicating the stronger metallic bonds of ω-Zr as the origin of the high shear strength and strain. In addition, based on the von Mises criteria, the dominating deformation mode for the polycrystalline material of ω-Zr is proposed along the { 1 0 1 ¯ 0 } 〈 0 0 0 1 〉 / { 1 0 1 ¯ 1 ¯ } 〈 1 ¯ 2 1 ¯ 0 〉 or { 1 1 2 ¯ 0 } 〈 0 0 0 1 〉 / { 1 0 1 ¯ 1 ¯ } 〈 1 ¯ 2 1 ¯ 0 slips, which is helpful to the understanding of deformation behavior in polycrystalline ω-Zr.

Polytetrafluoroethylene/poly(methyl methacrylate) (PTFE/PMMA) composites were prepared by a self-curing method. The influence of heat treatment processes on the friction and wear behaviors of PTFE/PMMA composites against bearing steel balls were studied by a ball-on-disk tribometer. The thermal performance of PTFE/PMMA composites with heat treatment was analyzed by Thermogravimetric Analysis (TGA). The surface morphologies and element distribution of PTFE/PMMA composites in a PMMA matrix were detected by Field Emission Scanning Electron Microscopy (FE-SEM) and Energy Dispersive Spectroscopy (EDS). The results indicated that the wear rates of PTFE/PMMA composites with different heat treatments significantly declined compared with the unheated treatment composite. The wear rate of the PTFE/PMMA composite decreased firstly and then increased with molding temperature and time increasing, and reduced with the molding pressure increasing. The main wear mechanisms of PTFE/PMMA composites with different heat treatments were fatigue wear and abrasive wear.

While theoretical simulations predict contradictory results about how the intercalation of foreign metal atoms affects the order of atomic layers in black phosphorus (BP), no direct experimental visualization work has yet clarified this ambiguity. By in situ electrochemical sodiation of BP inside a high-resolution transmission electron microscope and first-principles calculations, we found that sodium intercalation induces a relative glide of 1/2 ⟨010⟩ {001}, resulting in reordering of atomic stacks from AB to AC in BP. The observed local amorphization in our experiments is triggered by lattice constraints. We predict that intercalation of sodium or other metal atoms introduces n-type carriers in BP. This potentially opens a new field for two-dimensional electronics based on BP.

Element doping allows manipulation of the electronic properties of 2D materials. Enhanced transport performances and ambient stability of black-phosphorus devices by Te doping are presented. This provides a facile route for achieving airstable black-phosphorus devices.

Because of the unique layered structure, black phosphorus (BP) provides a possibility of relatively independent control in electrical and thermal conductivity for thermoelectrical applications. It is therefore of great interest to realize high-performance BP-based thermoelectrics as flexible non-toxic and ultralight devices in spite of the low energy conversion efficiency and structural instability of the bulk BP. In this work, we systematically study the thermoelectric properties for the two-dimensional BP from mono-layer up to quad-layer by first-principles calculations and Boltzmann transport theory. It can be concluded from the calculations that the thermoelectric performance of BP nanosheets can be effectively optimized by tuning the layer thickness. We reveal that the maximum ZT values at 300 and 500 K can reach up to 0.45 and 0.90 in p-type bi-layer BP along armchair direction, respectively, around 5 times higher than that of the bulk at room temperature. The high performance in bi-layer BP is mainly attributed to its highly anisotropic and degenerate carrier pockets. Accordingly, we further propose that the formation of BP/h-BN heterostructure can enhance ZT up to 1.2 at 500 K, which facilitates the real application of thin BP for flexible and eco-friendly thermoelectrics.

Layered black phosphorus (BP) has recently emerged as a promising semiconductor because of its tunable band gap, high carrier mobility and strongly in-plane anisotropic properties. One-dimensional (1D) BP materials are attractive for applications in electronic and thermal devices, owing to their tailored charge and phonon transports along certain orientations. However, the fabrication of 1D BP materials still remains elusive thus far. We herein report the successful synthesis and characterization of nanotube-like BP for the first time by a selective composite with hexagonal boron nitride (h-BN) nanotubes under high pressure and high temperature conditions. The produced 1D BP/h-BN composites possess flexible diameter, length and thickness by adjusting the experimental synthesis parameters. Interestingly, it is important to notice that the stability of our BP sample has been significantly improved under the formation of heterostructures, which can actively promote their commercial applications. Our experimental work, together with first-principles calculations, presents a new scalable strategy of designing 1D tube-like BP/h-BN heterostructures that are promising candidates for flexible and high efficiency electronic platform.

A novel method combined with fabric embossing (embossing with fabric template) and thermal annealing is proposed to prepare multistage textured superhydrophobic polytetrafluoroethylene (PTFE) surface. Multistage (four-stage) textures of microscale Y-grooves (≈175 µm), F-grooves (≈10 µm), warts (≈3 µm), and nanoscale dendrites (≈380 nm) were obtained. The multistage textures endowed the PTFE surface with better superhydrophobicity, comparing with the two-stage textures with Y-grooves and F-grooves or the two-stage textures with warts and dendrites. Optimum superhydrophobicity is obtained at thermal annealing temperatures 345 °C and 360 °C.

Flexible all-solid-state supercapacitors are fabricated with liquid-exfoliated black-phosphorus (BP) nanoflakes as an electrode material. These devices deliver high specific volumetric capacitance, power density, and energy density, up to 13.75 F cm(-3) , 8.83 W cm(-3) , and 2.47 mW h cm(-3) , respectively, and an outstanding long life span of over 30 000 cycles, demonstrating the excellent performance of the BP nanoflakes as a flexible electrode material in electrochemical energy-storage devices.

Cetyltrimethyl ammonium bromide–N-2-hydroxypropyl trimethyl ammonium chloride chitosan bentonite was prepared by modifying bentonite with cetyltrimethyl ammonium bromide and N-2-hydroxypropyl trimethyl ammonium chloride chitosan for the purpose of simultaneous sorption of aniline and Cr (VI) from aqueous solution. The optimal preparation conditions of cetyltrimethyl ammonium bromide–N-2-hydroxypropyl trimethyl ammonium chloride chitosan bentonite were listed as follows. For bentonite (5 g), the modifying reagents were 1.0 g cetyltrimethyl ammonium bromide and 1.0 g N-2-hydroxypropyl trimethyl ammonium chloride chitosan, respectively. The reaction was carried out for 2 h at 60°C. Adsorption experiments with single aniline and Cr (VI) solutions showed that the adsorption of aniline was caused by aniline partitioning between water and the organic-matter phase formed by conglomeration of the alkyl chains of cetyltrimethyl ammonium bromide, while the one of Cr (VI) was controlled by the electrostatic i...

Black phosphorous (BP) is a unique layered p-type semiconducting material. The successful use of BP nanosheets in field-effect transistors fueled research on BP atomic layers that focuses on, e.g., the exploration of their optical and electronic properties, and promising applications in (opto)electronics. However, BP films are prone to degradation in ambient conditions, which prevents their commercial application. Here, a route to the application of BP films as an environmental stable nonvolatile resistive random access memory is presented. The BP films, which are prepared from exfoliated BP nanosheets in selected solvents, show solvent-dependent degradation upon ambient exposure, inducing the formation of an amorphous top degraded layer (TDL). The TDL acts as an insulating barrier just below the Al electrode. This property that was only obtained by degradation, confers a bipolar resistive switching behavior with a high ON/OFF current ratio up to ~3 × 105 and excellent retention ability over 105 s to the flexible BP memory devices. The TDL also prevents propagation of degradation further into the film, ensuring excellent memory performance even after three month of ambient exposure.

Black phosphorus (BP), a two-dimensional (2D) material, has a direct bandgap that can be tuned by changing the layers and applied strain, which fills the lacuna left by graphene topological insulators and transition-metal dichalcogenides. Theoretically, the direct and tunable bandgap should enable broadband applications for optoelectronics with high efficiencies in the spectral range from the visible to the mid-infrared. Here, a BP broadband optical modulator is experimentally constructed and passively modulated lasers at 639 nm (red), 1.06 μm (near-infrared), and 2.1 μm (mid-infrared) are realized by using a BP optical modulator as the saturable absorber in bulk lasers. The obtained results provide a promising alternative for rare broadband optical modulators and broaden the application range of BP in photonics.

In the present paper, zirconium immobilized cross-linked chitosan (Zr-CCS) was reported for the adsorption of fluoride. Zr-CCS was synthesized by methods of membrane-forming and subsequent cross-linking reaction. Zr-CCS was characterized by FTIR, XRD, and SEM technologies. Batch adsorption experiments were performed to evaluate the adsorption capacity of Zr-CCS toward fluoride. The adsorption of fluoride onto the Zr-CCS favored at low pH values, and reduced in the presence of other co-anions. The adsorption equilibrium data had a good agreement with the Langmuir isotherm model, and the maximum adsorption capacity was calculated as 48.26mg/g for fluoride at 303K and natural pH (6.0). Thermodynamic parameters indicate that the nature of fluoride adsorption was spontaneous and endothermic. The adsorption mechanism of fluoride onto the Zr-CCS was controlled by chemical ion-exchange and electrostatic attraction between Zr-CCS and fluoride.

Zirconium-immobilized bentonite was prepared by hydrothermal reaction, and characterized by scanning electronic microscope (SEM) and X-ray diffraction (XRD) techniques. Removal of methyl orange (MO) from aqueous solutions with zirconium-immobilized bentonite was investigated by a batch method. These factors including adsorbent dosage, pH value of MO solution, and contact time were evaluated. Adsorption equilibrium was achieved at 60 min or so. The experimental isotherm data were described by the Langmuir isotherm model. The maximum adsorption capacity obtained from the Langmuir isotherm model was 44.13 mg/g at 298 K and natural pH value. An increase in temperature reduced the adsorption of MO while the increasing amount of zirconium enhanced the adsorption of MO onto Zr-immobilized bentonite. 1 M HCl was identified as the best eluent.

Recently, there have increasingly been debates on whether there exists a surface resonance state (SRS) in black phosphorus (BP), as suggested by recent angle-resolved photoemission spectroscopy results. To resolve this issue, we have performed temperature- and angle-dependent magnetoconductivity measurements on exfoliated, high-quality BP single crystals. A pronounced weak-antilocalization (WAL) effect was observed within a narrow temperature range of 8-16 K, with the electrical current flowing parallel to the cleaved ac-plane (along the a- or c-axis) and the magnetic field along the b-axis. The angle-dependent magnetoconductivity and the Hikami-Larkin-Nagaoka model-fitted results have revealed that the observed WAL effect shows surface-bulk coherent features, which supports the existence of SRS in BP.

Cross-linked chitosan/bentonite composite (CCB) was prepared, and characterized by Fourier transform infrared (FTIR) spectroscopy, BET surface area and pore diameter analyses, X-ray diffraction (XRD) patterns and thermal gravimetric analyses (TGA). The adsorption of hexavalent chromium Cr(VI) onto CCB as a function of adsorbent dosage, initial Cr(VI) concentration, solution pH, and contact time was investigated through batch experiments. The removal towards Cr(VI) decreased with increasing solution pH from 2 to 11 and initial Cr(VI) concentration, while it increased with increasing adsorbent dosage. The adsorption kinetic data of Cr(VI) on CCB were well described by the pseudo-second-order model. The equilibrium data were correlated by the Langmuir isotherm model. The maximum monolayer Cr(VI) adsorption capacity for CCB at pH 2 and 293 K was 89.13mg/g. The mechanisms for the adsorption of Cr(VI) on CCB at pH 2 may include electrostatic interaction and chemical interaction between CCB and Cr(VI) ions.

A monoclinic BC3 phase (denoted M-BC3) has been predicted using first principles calculations. The M-BC3 structure is formed by alternately stacking sequences of metallic BC-layers and insulating C atom layers, thus, the structure exhibits two-dimensional conductivity. Its stability has been confirmed by our calculations of the total energy, elastic constants, and phonon frequencies. The pressure of phase transition from graphite-like BC3 to M-BC3 is calculated to be 9.3 GPa, and the theoretical Vickers hardness of M-BC3 is 43.8 GPa, this value indicates that the compound is a potentially superhard material. By comparing Raman spectral calculations of M-BC3 and previously proposed structures with the experimental data, we speculate that the experimentally synthesized BC3 crystal may simultaneously contain M-BC3 and Pmma-b phases.

In this study, cross-linked chitosan (CCS)/bentonite (BT) composite was prepared by the intercalation of chitosan in bentonite and the cross-linking reaction between chitosan and glutaraldehyde. CCS/BT composite was characterized by using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and thermal gravimetric analyses (TGA). Their adsorption characteristics were assessed by using an azo dye (Amido Black 10B) as a model adsorbate. The adsorption of Amido Black 10B onto the CCS/BT composite was found to be optimal at pH 2. The adsorption isotherm was well described by the Langmuir model and the maximum adsorption capacity was 323.6 mg/g at 293 K and pH 2. Amido Black 10B adsorption kinetics followed a pseudo-second-order kinetic model. The calculated thermodynamic parameters showed that the adsorption of Amido Black 10B by CCS/BT composite was spontaneous and endothermic in nature.

We proposed a simple route for fabrication of the flexible BP nanoflake/carbon nanotube (CNT) composite paper as flexible electrodes in all-solid-state supercapacitors. The highly conductive CNTs not only play a role as active materials but also increase conductivity of the hybrid electrode, enhance electrolyte shuttling and prevent the restacking between BP nanoflakes. The fabricated flexible all-solid-state supercapacitor (ASSP) device at the mass proportion of BP/CNTs 1:4 was found to deliver the highest volumetric capacitance of up to 41.1 F/cm3 at 0.005 V/s, superior to the ASSP based on the bare graphene or BP. The BP/CNTs (1:4) device delivers a rapid charging/discharging up to 500 V/s, which exhibits the characteristic of a high power density of 821.62 W/cm3, while having outstanding mechanical flexibility and high cycling stability over 10 000 cycles (91.5% capacitance retained). Moreover the BP/CNTs (1:4) ASSP device still retains large volumetric capacitance (35.7 F/cm3 at the scan rate of 0.00...

A multifunction adsorbent, activated carbon (AC)/chitosan composite, was synthesized by incorporating AC into chitosan based on the ratio of AC to chitosan being 1/1. The simultaneous adsorption of aniline and Cu2+ from aqueous solution onto AC/chitosan composite was investigated by a batch procedure. These results showed that an adsorbent dosage of 0.3 g was appropriate, and a contact time of 210 min was convenient for reaching adsorption equilibriums for aniline and Cu2+. The simultaneous adsorption of aniline and Cu2+ was realized in a wide pH range. The adsorption process obeyed the pseudo-second-order kinetic model. The adsorption behaviors of aniline and Cu2+ followed Freundlich and Langmuir, respectively. No obvious competitive adsorption existed between Cu2+ and aniline.

A multifunction adsorbent was synthesized by incorporating AC into CTS, and the ratio of AC to CTS was 1/1. The resultant was called activated carbon (AC)/chitosan (CTS) composite. The simultaneous adsorption of phenol and Cu2+ from aqueous solution onto AC/CTS composite was investigated by a batch procedure. The adsorption processes for both Cu2+ and phenol obeyed the pseudo second-order kinetic model. Phenol was prone to be adsorbed more quickly as compared with Cu2+ when they coexisted in solution. The adsorption behavior of both phenol and Cu2+ followed the Langmuir isotherm. The maximum adsorption capacities of phenol and Cu2+ were 34.19 mg/g and 74.35 mg/g at 293 K, respectively. No obvious competitive adsorption existed between phenol and Cu2+.

Layered germanium phosphide, which combines the advantages of both germanium and phosphorus, is believed to be a potential anode for sodium ion battery. Here, the sodium storage mechanism and electrochemical performance of layered germanium phosphide have been deeply investigated by advanced in-situ transmission electron microscopy technique combining half-cell testing. Dynamic reaction process reveals that individual layered germanium phosphide nanoflake undergoes total area expansion of 248% without any detectable fracture or cracking in sodiation. In contrast, germanium phosphide experiences multi-step reactions, i.e. intercalation and alloying, accompanied by sequentially forming NaxGeP (0

The simultaneous adsorption of phenol and Cr(VI) from aqueous solution onto this activated carbon/chitosan composite was investigated. This composite almost removes phenol and Cr(VI) simultaneously in a pH range of 2–5. The removals of phenol and Cr(VI) reached up to 95% when phenol and Cr(VI) concentrations were less than 50 mg/L and 200 mg/L, respectively. The presence of phenol reduced Cr(VI) adsorption, while the presence of Cr(VI) had no evident effect on phenol adsorption. The adsorption for both Cr(VI) and phenol followed pseudo-second-order kinetics in single or mixedsystems. © 2013 American Institute of Chemical Engineers Environ Prog, 33: 814–823, 2014