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Non-enzymatic voltammetric analysis of epinephrine (EP) was conducted based on three-dimensional rosette vanadium sulfide nanosheet spheres-reduced graphene oxide nanosheets/indium tin oxide (VS2 NSSs-RGO/ITO) electrode. The results show that the diameter of VS2 NSSs is about $5~\mu \text{m}$ and the thickness of nanosheet is 200 nm, and the RGO is a transparent sheet structure with some folds. The electrode exhibits an enhanced electrochemical response in EP analyte, which shows a high sensitivity of $1.39\,\,\mu \text{A}\cdot \mu \text{M}^{-1}$ towards EP (0– $60~\mu \text{M}$ ) and the lowest detection limit obtained is $0.017~\mu \text{M}$ (S/N = 3). The electrode also exhibits an excellent selectivity, repeatability and stability. The prepared sensor has been successfully applied in real samples and it has a great potential to be used in clinical test.

As an inexpensive and naturally abundant two-dimensional (2D) material, molybdenum disulfide (MoS

Silicon has gained considerable attention as an anode material in lithium-ion batteries due to its high theoretical capacity. However, the significant volume changes that occur during lithiation/delithiation processes often result in poor cycling stability of silicon anodes. In this study, a hybrid ionically covalently cross-linked network binder carboxymethylcellulose-hyperbranched polyethyleneimine (CMC-HBPEI) is successfully constructed by “switching” ionic bonds and partially “converting” them to covalent bonds to buffer the volume variation of silicon anodes. In this hybrid cross-linked network, the covalently cross-linked network is responsible for maintaining the structural integrity of the anode, while the ionically cross-linked network utilizes the bonding reversibility to sustainably dissipative the mechanical stress and self-heal the structural breakages generated from the lithiation expansion of silicon. By changing the drying temperature of the anode, the ratio of covalent and ionic bonds in the hybrid cross-linked network can be adjusted to balance the mechanical stability and bonding reversibility of the CMC-HBPEI binder. Even after 300 cycles of charging/discharging under a current density of 500 mAg−1, the specific capacity of the optimized Si/CMC-HBPEI anode remains at 1545 mAhg−1.

It is important for the development of high-performance dielectric materials to reduce the dielectric constant and water uptake simultaneously, with the maintenance of mechanical properties. Herein, sandwich-type composite film was prepared through coating the both sides of flat polyimide (PI) film with polyhedral oligomeric silsesquioxanes (POSS) contained hierarchical porous structure using the microemulsion method, in which water droplets were used as the template for patterned pores. Due to the introduction of two layers of hierarchical porous structure with patterned pores and POSS, the dielectric constant of PI film was significantly reduced, accompanied by the low dielectric loss. In addition, the water uptake was also greatly reduced, thus contributing to its excellent durability under high humidity. More importantly, even with the introduction of porous structure, the mechanical properties of PI film can still be maintained, or even improved by optimizing POSS content. Through varying the POSS content from 10 to 50%, low dielectric constant of 2.28–2.42, dielectric loss of 0.005–0.009, water uptake of 0.56–0.62%, increment of dielectric constant under high humidity of 1.19–2.35%, with 26–32%, 43–69%, 77–80% and 31–37% of reduction, respectively, compare to flat PI film were achieved. These results indicate the potential of our sandwich-type composite film as low dielectric material in microelectronics.

Two-dimensional (2D) molybdenum disulfide (MoS2) has been recognized as a potential substitution of platinum (Pt) for electrochemical hydrogen evolution reaction (HER). However, the broad adoption of MoS2 is hindered by its limited number of active sites and low inherent electrical conductivity. In this work, we employed a one-step solvothermal synthesis technique to construct a ternary hybrid structure consisting of dual-phase MoS2, titanium carbide (Ti3C2) MXene, and carbon nanotubes (CNTs), and demonstrated synergistic effects for active site exposure, surface area enlargement, and electrical conductivity improvement of the catalyst. The dual-phase MoS2 (DP-MoS2) is directly formed on the MXene with CNTs acting as crosslinks between 2D islands. The existence of edge-enriched metallic phase MoS2, the conductive backbone of MXene along with the crosslink function of CNTs clearly improves the overall HER performance of the ternary nanocomposite. Moreover, the integration of MoS2 with MXene not only increases the interlayer distance of the 2D layers but also partially suppresses the MXene oxidation and the 2D layer restacking, leading to good catalytic stability. As a result, an overpotential of 169 mV and a low Tafel slope of 51 mV/dec was successfully achieved. This work paves a way for 2D-based electrocatalyst engineering and sheds light on the development of the next-generation noble metal-free HER electrocatalysts.

Metal sulfide-graphene hybrid materials have attracted increased attention as promising supercapacitor electrode materials. Herein, three-dimensional multi-layered graphene (3D GR) is prepared by chemical vapor deposition using nickel nanowires (Ni NWs) as the template and then, indium sulfide nanosheet arrays (In2S3 NSAs) were grown on the 3D GR by hydrothermal synthesis to obtain In2S3 NSA/3D GR composite. The hybrid is characterized by scanning and transmission electron microscopy, X-ray diffraction, and Raman scattering. The electrode exhibits a high specific capacitance of 530.7 F g−1 at 1 A g−1. Moreover, the electrode possesses an excellent cycle life with 84% capacitance retention after 20,000 cycles at 1 A g−1.

In this paper, a simple and efficient electrochemical sensor based on indium sulfide nanosheet arrays (In2S3 NSAs) grown on 3D graphene (3D Gr) has been developed. 3D Gr was obtained by chemical vapor deposition (CVD) and In2S3 NSAs were prepared by a hydrothermal method. The composite (In2S3 NSAs-3D Gr) has a large accommodation space to contact with biological molecules. The current generated by the redox reaction of epinephrine (EP) on the surface of the In2S3 NSAs-3D Gr becomes an important indicator of the sensor value. The sensitivity of the sensor for the detection of EP in the range of 0–60 µm is 2.46 µA µM− 1 with a detection limit of 0.12 µM (S/N = 3). Meanwhile, the novel sensor has a good stability and selectivity. It also has potential for real detection of EP in human serum.

A novel hybrid of polyaniline nanowire array/three-dimensional hollow graphene balls-graphene oxide (PANI NWA/3D HGBs-GO) is prepared. 3D HGBs are first fabricated by template-oriented carbon segregation, and then PANI NWAs are grown on their surface by in situ polymerization to obtain PANI NWA/3D HGBs. Finally, the surface of PANI NWA/3D HGBs is modified by hexadecyl trimethyl ammonium Bromide (CTAB), and PANI NWA/3D HGBs and GO are combined by electrostatic self-assembly method to obtain PANI NWA/3D HGBs-GO composite. Due to the unique structure, the hybrid exhibits a high specific capacitance of 690.0 F·g−1 at 1 A·g−1. When it is assembled into a symmetric supercapacitor, it exhibits an energy density of 30.9 Wh·kg−1 at a power density of 690.1 W·kg−1 and maintains a good cycle stability of 90% after 10,000 cycles at 1.0 A·g−1.

A nonenzymatic voltammetric assay for dopamine (DA) was developed based on the combination of three-dimensional graphene (3D Gr) and indium oxide nanosheet arrays (In2O3 NSAs). 3D Gr was prepared by chemical vapor deposition (CVD), and In2O3 NSAs were grown on its surface by hydrothermal synthesis. The results show that 3D Gr maintains a good porous structure (200 μm), and the pore size of In2O3 NSAs is 0.50 μm. Differential pulse voltammetry (DPV) is mainly used to determine the electrochemical properties of In2O3 NSAs/3D Gr. It possesses a sensitivity of 2.69 μA·μM−1·cm−2 towards DA (5–60 μM) at 0.14 V, and the detection limit (LOD) is 0.10 μM (S/N = 3). The recoveries obtained for spiked samples in the real sample detection is 105 (± 8)%.

Three-dimensional graphene (3D GR)-based hybrids have received significant attention due to their unique structures and promising applications in supercapacitors. In this paper, 3D GR with small pore sizes has been prepared by chemical vapor deposition using commercial nickel nanowires as the template. After nitric acid treatment, the hydrophilicity of 3D GR improved. Polyaniline nanowire arrays (PANI NWAs) have been successfully grown on its surface by in situ polymerization to obtain hybrid PANI NWA/3D GR. The results show that PANI NWAs with a length of ∼300 nm vertically grow on 3D GR with a pore diameter of ∼2 μm. The small pore size of 3D GR not only improves the mechanical properties of 3D GR, but also provides numerous sites for the growth of PANI NWAs. Meanwhile, PANI NWAs provide a shorter ion diffusion path and larger contact area with the electrolyte. Due to the unique structure, the hybrid exhibits a high specific capacitance of 789.9 F g-1 at 10 mV s-1. When it is assembled into a symmetric supercapacitor, it exhibits an energy density of 32.2 W h kg-1 at a power density of 793.3 W kg-1 and maintains a good cycle stability of 90% after 5000 cycles at 1.0 A g-1.

Using a simple hydrothermal process, ZnO nanosheet balls (ZnO NSBs) were in situ synthesized on three-dimensional graphene foam grown by chemical vapor deposition using nickel foam as the template. The hybrid ZnO NSB/GF was acted as a free-standing electrode for electrochemical detection of dopamine in the presence of uric acid. The results show that ZnO NSBs with the diameter of ∼2 μm and sheet thickness of ∼50 nm are distributed on the surface of GF. The ZnO NSB/GF electrode exhibits a high sensitivity of 0.99 μA μM−1 for the determination of dopamine. It also shows a low detection limit, good selectivity, reproducibility and stability. And it is potential for use in clinical research.

Graphene reinforced copper matrix composites (Gr/Cu) were fabricated by electrostatic self-assembly and powder metallurgy. The morphology and structure of graphene oxide, graphene oxide-Cu powders and Gr/Cu composites were characterized by scanning electronic microscopy, transmission electronic microscopy, X-ray diffraction and Raman spectroscopy, respectively. The effects of graphene contents, applied loads and sliding speeds on the tribological behavior of the composites were investigated. The results indicate that the coefficient of friction of the composites decreases first and then increases with increasing the graphene content. The lowest friction coefficient is achieved in 0.3 wt% Gr/Cu composite, which decreases by 65% compared to that of pure copper. The coefficient of friction of the composite does not have significant change with increasing the applied load, however, it increases with increasing the sliding speed. The tribological mechanisms of the composite under different conditions were also investigated.

Graphene foam (GF) was synthesized by chemical vapor deposition (CVD) using nickel foam as the template. Then, ZnO nanowire arrays (ZnO NWAs) were grown on the GF by hydrothermal synthesis. Finally, graphene (Gr) was deposited on the ZnO NWAs by CVD to obtain the hybrid of Gr/ZnO NWAs/GF. Due to large specific surface area and outstanding electric conductivity, the hybrid can be used for the determination of folic acid (FA) by cyclic voltammetry and differential pulse voltammetry. The results show that ZnO NWAs are uniformly and vertically grown on the GF and Gr is deposited on the ZnO NWAs. The sensitivity and the measured detection limit of the hybrid for FA in the range of 0–60 μM are 0.18 μA μM− 1 and 1 μM, respectively. The hybrid can accurately detect FA in the presence of uric acid, and the hybrid also shows good reproducibility and stability.

The development of active catalysts for hydrogen evolution reaction (HER) made from low-cost materials constitutes a crucial challenge in the utilization of hydrogen energy. Earth-abundant molybdenum disulfide (MoS2) has been discovered recently with good activity and stability for HER. In this report, we employ a hydrothermal technique for MoS2 synthesis which is a cost-effective and environmentally friendly approach and has the potential for future mass production. Machine-learning (ML) techniques are built and subsequently used within a Bayesian Optimization framework to validate the optimal parameter combinations for synthesizing high-quality MoS2 catalyst within the limited parameter space. Compared with the heavy-labor and time-consuming trial-and-error approach, the ML techniques provide a more efficient toolkit to assist exploration of the most effective HER catalyst in hydrothermal synthesis. To investigate the structure-property relationship, scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), and various electrochemical characterizations have been conducted to investigate the superiority of the ML validated optimized sample. A strong correlation between the material structure and the HER performance has been observed for the optimized MoS2 catalyst.

ZnO nanorods and graphene foam were synthesized via hydrothermal synthesis and chemical vapor deposition, respectively. Hybrid of ZnO nanorods and graphene nanosheets was prepared by ultrasonic treatment. The hybrid was sprayed onto the ITO glass. The hybrid was characterized by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The electrochemical properties of the hybrid were measured by cyclic voltammetry and differential pulse voltammetry. The results show that the diameter and length of ZnO nanorods are ~ 50 nm and 5 μm, respectively. Graphene nanosheets with high quality are made up of few layers and the sheet size is ~ 2 μm. The sensitivity of the hybrid for detection of uric acid is 0.3 μM μA−1 cm−2 in the range of 5~80 μM. The electrode can accurately detect uric acid in the presence of ascorbic acid. Meanwhile, the electrode also shows good repeatability and stability.

Graphene foam (GF) was fabricated by chemical vapor deposition using nickel foam as the template and the GF was activated by concentrated nitric acid. Polyaniline nanowire arrays (PANI NWAs) were grown on the surface of GF by in-situ polymerization to obtain the PANI NWAs/GF composite. The morphologies and structures of GF and PANI NWAs/GF composite were characterized by scanning electron microscopy, transmission electron microscopy and Raman analysis, respectively. The integration between GF and PANI NWAs shows a synergistic effect. GF provides electrically conductive channels for the PANI NWAs anchored on it, and PANI NWAs with small diameters provide high pseudocapacitance and enhanced electrode specific surface area. The electrode exhibits a high specific capacitance 870 F g−1 at 1 A g−1. Moreover, the electrodes possess an excellent cycle life with 80% capacitance retention after 1000 cycles at 6 A g−1.

Graphene nanosheets (GNSs) reinforced pure copper matrix composites were prepared by ball-milling and hot-press sintering. The morphologies and structures of GNSs-Cu powders were studied after ball-milling for different time. The effects of the GNSs content on the microstructures, mechanical properties and fracture mechanisms of the composites were also investigated. It is indicated that the GNSs are gradually dispersed into the copper matrix with increasing the ball-milling time and a uniform dispersion is achieved after ball-milling for 5 h. When the content of GNSs in the composite is 0.5 wt%, GNSs distribute randomly in the composite and the interface bonding is good which is benefit to enhance the mechanical properties of composite. With increasing the GNSs contents, the aggregation of GNSs in the composite is apparent, which seriously separates the matrix and results in low mechanical properties. The fracture mechanism of the composites changes from ductile to brittle.

A nonenzymatic voltammetric assay for dopamine (DA) was developed based on the combination of three-dimensional graphene (3D Gr) and indium oxide nanosheet arrays (In

The graphene oxide (GO) nanosheets as well as the two-dimensional Ni(OH)2 with excellent uniformity were prepared with a hydrothermal and Hummers method, respectively. Ni(OH)2 nanosheets treated by cationic surfactants and graphene oxide with negative charges were mixed by electrostatic self-assembly. After annealing, hybrid two-dimensional NiO-reduced graphene oxide nanosheets (NiO-rGO) were obtained. Attributing to the synergistic effects, the NiO-rGO electrode exhibits an optimized electrochemical performance, in contrast to pure NiO or rGO supercapacitor. The results show the NiO nanosheets are homogeneously dispersed on the surface of rGO nanosheets and the hybrid NiO-rGO nanosheets electrode can deliver an excellent capacity of 343 C·g−1 (1 A·g−1). Furthermore, the electrodes made up of NiO-rGO nanosheets are employed to assemble symmetric supercapacitor. The energy density of as-prepared supercapacitor device can reach up to 5.4 Wh·kg−1 at a power density of 0.43 kW·kg−1 operated in the voltage range of 0–1.4 V. In addition, the symmetric supercapacitor also exhibits an excellent capacitance retention of 90% after 10,000 cycles (10 A·g−1).

Low-dielectric-constant materials are in great demands to satisfy the requirements in microelectronics. In this study, polyhedral oligomeric silsesquioxanes (POSS) contained hierarchical porous structure, which was prepared by the self-assembly of water droplets, was used as a coating for flat polyimide (PI) film. Evident declines were found in dielectric constant and water uptake upon the introduction of the hierarchical porous coating due to the existence of fluorine-containing groups, POSS and the hierarchical porous structure. In addition, almost undamaged mechanical properties were shown when the dielectric and water resistance properties were optimized because the hierarchical porous structure was used as a coating but not the bulk of the PI film. When the content of POSS varies from 10 % to 50 %, low dielectric constants of 2.42–2.75 and low water uptakes of 0.60 %– 0.67 %, with 22 %–27.63 % and 75.96 %–78.43 % of reductions were obtained, compared to 3.36 of dielectric constant and 2.80 % of water uptake for flat PI film. More importantly, the stability of dielectric properties in humid environment was verified by only 2.94 %–4.83 % of increase in dielectric constant after exposing to high humidity for more than 25 h, compared to 9.43 % of increase for flat PI film. The present study provides a versatile method for the preparation of low-dielectric-constant polymer materials with comprehansive properties.

The dispersion of graphene in copper matrix significantly affects the mechanical and physical properties of graphene reinforced copper matrix composite (Gr/Cu). In our present study, graphene oxide (GO) with the negative charge was prepared by a modified Hummers' method and Cu powders were coated by hexadecyl trimethyl ammonium bromide (CTAB) to obtain the surface positive charge. GO-Cu powders were prepared by electrostatic self-assembly and Gr/Cu composites were fabricated by powder metallurgy. Morphologies of GO-Cu powders, microstructures and tensile fractographs of the Gr/Cu composites were observed. The effect of graphene contents on the mechanical properties and thermal conductivity of the composite were also investigated. The results show that GO with the negative charge is adsorbed on the surface of CTAB coated Cu powders with the positive charge, which realizes the homogeneous dispersion of graphene in the copper matrix composites. With increasing the graphene contents, the ultimate tensile strength and thermal conductivity of Gr/Cu composites initially increase and later decrease. However, the elongation to fracture of the composite gradually decreases.

Aluminum borate whiskers (ABOw) with or without ZnAl2O4 coating reinforced pure aluminum composites (ABOw/Al, ABOw/ZnAl2O4/Al) were fabricated by squeeze casting. The effects of ZnAl2O4 coating on the compressive behaviors, microstructures, and matrix textures of the composites were investigated at different temperatures and strain rates. The results indicate that the maximum compressive flow stress of the composites almost linearly decreases with the increase in temperature. The maximum compressive flow stress of ABOw/ZnAl2O4/Al composite is higher than that of ABOw/Al composite at the same temperature when the strain rate is larger, however, it is reversed when the strain rate is smaller. It is more serious for the fracture of whiskers in ABOw/ZnAl2O4/Al composite than that in ABOw/Al composite at the high compressive strain rate. However, the average length of whiskers in ABOw/ZnAl2O4/Al composite is larger than that in ABOw/Al composite at the low compressive strain rate. The strong matrix tex...

As a ubiquitous phenomenon in nature, chirality plays a pivotal role in a variety of biological and physiological processes. The construction of chiral interfaces and exploration of their effect on the behavior of various substances, especially biomolecules such as DNA, proteins and cells, are effective ways to fully understand the chirality in nature and to further develop their applications. In order to accelerate the research process of chiral mechanism and provide new ideas for the interpretation of chiral phenomena in nature, thus further promoting the applications of chiral effect in biology, medicine and other related fields, various types of chiral interfaces were prepared and their effects on drug molecules, biomolecules and cells have also been investigated. This review covers the preparation of various chiral interfaces with different geometrical structures and the stereoselective interaction between biological or related systems and the chiral interface materials. Moreover, some challenges and perspectives are also presented.

MoS2 nanoflowers (NFs) prepared by hydrothermal synthesis were mixed with graphene oxide (GO) suspension prepared by Hummers method. Then, the mixture was spray coated on indium tin oxide (ITO) glass. After heatment, MoS2 NFs-reduced GO/ITO (MoS2 NFs-rGO/ITO) was obtained and used as a working electrode to electrochemically detect dopamine and uric acid simultaneously. The results are as follows: MoS2 NFs with the diameter of ~ 1 μm are composed by nanosheets and the graphene with a high transparence and large number of folds is coated on the surface of MoS2 NFs. A large number of holes form in the electrode so that bioactive molecules can easily enter and contact with the hybrid. The electrode exhibits a high sensitivity (2.29 and 1.88 μA μM−1) for the determination of dopamine and uric acid. The electrode also shows a low detection of limit, good anti-interference and stability. And it can be used for detecting real biomolecules.

The development of novel nanomaterials brings new opportunity and challenge for high sensing detection of biomolecules. The authors describe the preparation of 3-dimentional hollow graphene balls (3D HGBs) using nickel nanoparticles (Ni-NPs) as the template. The Ni-NPs were synthesized by chemical reduction of nickel chloride and then graphene was coated onto their surface via carburization and carbonization. After etching Ni-NPs, 3D HGBs with few layers and a typical size of 100 nm were obtained. They were sprayed onto indium tin oxide glass to obtain a working electrode for electrochemical determination of levodopa in the presence of uric acid. Due to the unique hollow porous structure of the 3D HGBs, the electrode exhibits a sensitivity of 0.69 μA·μM−1·cm−2 and a 1 μM limit of detection. It is selective, reproducible and stable. It was applied to the determination of levodopa in spiked human plasma samples and it is of potential use in clinical research.

2024Al composites reinforced by aluminum borate whiskers with different ZnO coating contents were fabricated by squeeze casting. The effects of the coating contents and T6 heat-treatment on the bending properties of the composites were investigated. The results show that the bending properties of the composite firstly increase and later decline with increasing ZnO coating contents of the whiskers. T6 heat-treatment of the composites can further improve the bending properties of the composites. On the analysis of fractographs, the fracture mechanisms of the composites under bending were also investigated.

The free-standing Si-coated carbon nanofiber (Si/CNF) mat was fabricated for the anode of lithium ion battery through combining electrospun CNF mat with electrodeposited Si layer. Spaghetti or granule-like Si was obtained by varying the deposition conditions. This Si/CNF mat was directly used as an active material and a current collector as well, which involves neither binders nor additional metal substrate. The best performance was achieved in spaghetti-like Si due to its highly porous nature which can accommodate volume expansion and large surface area which benefit the efficient charge transfer both at Si/CNF interface and at the electrode/electrolyte interface. The optimized Si/CNF mat after annealing at 1000 degrees C delivered a capacity of 870 mA h g(-1) at 1st discharge and 730 mA h g(-1) at 50th discharge with a capacity retention of 84%, improving the capacity of pure CNF (280 mA h g(-1) at the 50th discharge) by almost three times. In addition, corrosion of the current collector no longer exists in our approach. Our X-ray photoemission spectroscopy and electrochemical analysis revealed that the formation of Si-C bond through high temperature annealing can enhance the adhesion between silicon and carbon at the interface which benefits the cyclic performance of anode ultimately. (C) 2014 Elsevier Ltd. All rights reserved.

ZnO coating of the aluminum borate whiskers was prepared by sol–gel and 2024Al composite reinforced by the ZnO coated aluminum borate whiskers was fabricated by squeeze casting. Tensile properties and aging behaviors of the composite were investigated. The results show that the ZnO coating of the whiskers reacts with molten 2024Al during squeeze casting and simultaneously a layer of uniform MgAl 2 O 4 forms at the interface. The tensile properties of the composite are the largest after the solid solution treatment at 490 °C for 2 h and the aging treatment at 170 °C for 8 h. The ZnO coating of the whiskers significantly changes the aging behaviors of the aluminum borate whiskers reinforced 2024Al composite.

We report a facile, size-controllable exfoliation process using an ultrasound-assisted liquid method to fabricate few-layer molybdenum disulfide (MoS2) nanosheets. The morphology, structure and size distribution of the nanosheets processed with different ultrasonic powers were examined by atomic force microscopy, Raman spectroscopy and dynamic light scattering. It was revealed that the size of nanosheets reduces and final yield increases with elevating ultrasonic power. Bulk and exfoliated MoS2 based thin film sensors are fabricated by a simple drop casting method on alumina substrates. Our sensors exhibit excellent sensitivity with very quick response and recovery speed to humidity gas. Comparative studies are carried out to draw up the size or ultrasonic power dependent sensing behavior.

The high-temperature stabilization of ZnO nanorods synthesized by hydrothermal treatment was investigated. The structure and morphologies of ZnO nanorods were characterized by XRD and SEM, respectively. The thermal stability of ZnO nanorods was also detected by thermal gravity analyzing. Thermal annealing treatment results indicate that ZnO nanorods are fundamentally stable when annealing temperature is lower than 600 °C. When annealing temperature is beyond 600 °C, the diameters of ZnO nanorods obviously decrease and the aggravating tendency of nanorods between each other also increase. Annealing treatment can greatly influence the gas sensing properties of ZnO nanorods. Comparing with ZnO nanorods without annealing treatment, the gas sensing property of ZnO nanorods to H 2 with concentration of 2.5×10 −6 can increase from 2.22 to 3.56. ZnO nanorods annealed at 400 °C exhibit optimum gas sesing property to H 2 gas.

Three-dimensional graphene-based hybrid is a promising supercapacitor electrode material. Herein, a novel hybrid of polyaniline nanowire array/three-dimensional hollow graphene balls (PANI NWA/3D HGBs) is prepared. Three-dimensional hollow graphene balls (3D HGBs) are first fabricated by template-oriented carbon segregation and then polyaniline nanowire arrays (PANI NWAs) are grown on their surface by in-situ polymerization of aniline monomers. The results show that PANI NWAs with the length of ∼200 nm are vertically grown on 3D HGBs with a diameter of ∼500 nm. 3D HGBs act as the stable skeleton during long-term cyclic testing, and PANI NWAs provide a larger contact area with the electrolyte and a direct ion diffusion path. The hybrid exhibits a high specific capacitance of 635 F⋅g−1 at 1 A⋅g−1. When it’s assembled into a symmetric supercapacitor, it exhibits an energy density of 25.3 Wh⋅kg−1 at a power density of 553.4 W⋅kg−1 and maintains a good cycle stability of 89% after 5000 cycles at 1.0 A⋅g−1.

Novel hierarchical ZnO nanomaterials with castellated and turriform morphologies were successfully synthesized by ultrasonic assisted hydrothermal route. The morphology and structure of products were characterized by scanning electron microscopy and X-ray diffraction, respectively. The results show that as-prepared castellated ZnO microrods have six-equal axis symmetry features with the length of 2–4 μm and the diameter of about 1 μm, and ZnO with turriform morphology has radical branch structure with the diameter ranging from 500 to 700 nm. It is found that initial alkaline concentration of the solution plays a crucial role in determining two kinds of hierarchical morphologies by etching ZnO crystal during hydrothermal process. A possible formation mechanism of castellated and turriform ZnO microstructures is also proposed. Gas sensing of hierarchical ZnO to different gases was also examined. The result indicates turriform ZnO sensor has fast response properties and excellent selective resolution capability to C2H5OH gas.

ZnO and ZnAl 2 O 4 -coated Al 18 B 4 O 33 whisker reinforced pure aluminum composites were fabricated by squeeze casting. The effects of the coating contents on the ultimate tensile strength (UTS), 0.2% proof stress ( σ 0.2 ) and elongation to fracture ( δ ) of the composites were investigated. The results show that the UTS of ZnO-coated Al 18 B 4 O 33 whisker reinforced aluminum composites increases almost linearly as the coating contents increase. However, the UTS of ZnAl 2 O 4 -coated Al 18 B 4 O 33 whisker reinforced aluminum composites declines initially and increases later. The ZnAl 2 O 4 coating of the whiskers is more favorable for an increase in the σ 0.2 of the composites. The δ of the composites obtains its maximum value with an appropriate coating content. Fracture mechanisms of the composites were also investigated.

Defect-rich single-walled carbon nanotubes (SWCNTs) were prepared by a water vapor flow-assisted chemical vapor deposition process. The correlation between defect density and water flow was quantitively studied using Raman spectrum. The detection capabilities of defective SWCNTs films toward perchlorate anions were investigated. It was found the defect-rich SWCNTs could adsorb more perchlorate anions owing to the strong chemical bonding between anions and defective sites. However, the detective response of defective SWCNTs toward perchlorate was not in compliance with anion adsorption. A tradeoff phenomenon between response and adsorption was found as the defect density of SWCNTs increased. This work is expected to provide a guidance to the future design of SWCNTs based ion detector.

A pure aluminum composite reinforced by Al18B4O33 whiskers was fabricated by a squeeze casting technique. In the present study, it is found that the dependence of tensile plasticity on temperature in Al18B4O33 whiskers reinforced aluminum composite is different from other discontinuously reinforced aluminum composites. The tensile elongation to fracture of the composite obtains its maximum value at about 573 K, which is considered to be related to the equicohesive temperature of interface and matrix. This will also establish a basis for the research of hot forming process of the composite at elevated temperatures.