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Hierarchical Ni(OH)2–MnO2 hollow spheres are prepared via a simple self-templating route. The structural and compositional advantages of the Ni(OH)2–MnO2 material endow it with remarkable performance as a supercapacitor.

Engineering the interface plays a vital role in tuning the catalytic properties of supported metal nanocatalysts. Herein the 0.73%Au-4.13%FeOx@SBA-15 catalyst was constructed with SBA-15 as support and FeOx as modifier by interface engineering. It exhibited better catalytic activity than 0.71%Au/SiO2, 0.69%Au@SBA-15 and 0.71%Au/bulk-FeOx under identical conditions as well as higher selectivity towards cinnamyl alcohol for selective hydrogenation of cinnamaldehyde. It was found that the introduction of FeOx fabricated the interfacial area between Au and FeOx for H2 dissociation and consequently led to higher catalytic activity of 0.73%Au-4.13%FeOx@SBA-15. Meanwhile, both the channel of the SBA-15 support and the presence of small-sized FeOx promoted the selectivity for hydrogenation of C = O bond. It demonstrated for the first time that the interface engineering provided an efficient and facile avenue to design Au catalysts of excellent performances for selective hydrogenations.

Modulating the phase property of electrode materials is of intrinsic importance for enhanced energy storage performance. Here, through a pillar-coordinated strategy, a series of metaborate pillar-c...

Au nanoparticles confined within the mesopores of the modified SBA-15 were obtained through adsorption-reduction method and firstly employed as chemoselective catalyst for quinoline hydrogenation. The effects of Au loadings, calcination temperature as well as structure of support on catalytic performances of Au catalysts were explored. The as-obtained 1.2%Au@SBA-15-500 catalyst exhibited high activity, excellent selectivity towards 1,2,3,4-tetrahydroquinoline and extraordinary sintering-resistant property as high as 800 °C, which is sharp contrast to the 1.3%Au/SiO2-500 catalyst. It also showed good recyclability and versatility for quinoline derivatives. The observed properties were assigned to small-sized Au nanoparticles and mesopores of SBA-15. Our work provides a facile and promising approach to construct metal nanocatalysts with high catalytic performance by the use of mesoporous materials.

Effects of preparation parameters of NiAl oxide-supported Au nanocatalysts on their performance in the chemoselective hydrogenation of nitro compounds were investigated. The deposition–precipitation method, low Au loading, and low Ni/Al molar ratio of the support contributed to the generation of small-sized Au nanoparticles. High catalytic properties were related to the small sizes of Au particles and appropriate basicity of supports. Accordingly, the 0.43% Au/NiAlO-2-500 (the Ni/Al molar ratio of the support = 2) showed high activity and excellent selectivity for nitro hydrogenation. It also showed good versatility for other nitro compounds and good recyclability. Interestingly, for the first time, this Au catalyst switched its selectivity to vinyl hydrogenation by mere regulation of the composition of the support (the Ni/Al molar ratio of the support = 4). The observed shift in selectivity was ascribed to the different adsorption behaviors of the nitro and vinyl group on Au nanocatalysts. It provides a novel and facile strategy to construct Au nanocatalysts with high activity and switchable selectivity for hydrogenation of nitro compounds by the fine tuning of preparation parameters.

Porous biomass carbon materials were successfully synthesized from wheat straw by a citric-acid-crosslinking and KOH-activating method. Structural characterization results indicate that the as-obtained biomass carbon materials have hierarchical porous structure and high specific surface area. Electrochemical test demonstrates that the porous biomass carbon materials from wheat straw have the optimal super-capacitive properties when the quality of KOH is 5 times that of the carbonization product, i.e.: high specific capacitance of 294 F g−1, superior rate performances of 200 F g−1 at 10 A g−1 and excellent cycle stabilization (97.6% of capacitance retention after 5000 cycles). More importantly, porous biomass carbon from wheat straw with the optimal performance was assembled into flexible, all-solid-state, symmetric supercapacitors. The assembled symmetric supercapacitors reveal high energy density (14 Wh kg−1 at 440 W kg−1 power density) and excellent cycle stability (only 4.3% capacitance loss after 8000 cycles). Meanwhile, the present full-cell supercapacitors manifest the remarkable flexibility, low-temperature resistance, and commercial value. Hence one can see that all-solid-state supercapacitors based on porous biomass carbon derived from wheat straw have great potential prospect in the field of portable and wearable electronic devices.

Electrochemical materials with ordered nanostructure are widely researched due to the larger contact area with electrolyte and higher utilization rate of electroactive material. Therefore, Ni(OH)2-Co2(OH)3Cl bilayer nanocomposites are firstly synthesized and directly used as binder-free electrodes of high-performance hybrid supercapacitors. Structural characterization results indicate that the as-obtained products belong to bilayer nanocomposites, i.e.: the underlying inter-crosslinked nanosheets are Ni(OH)2 and the upper embellished flower-like materials are Co2(OH)3Cl. Electrochemical tests demonstrate that Ni(OH)2-Co2(OH)3Cl bilayer nanocomposites possess higher specific capacity compared with inter-crosslinked Ni(OH)2 nanosheets. More importantly, hybrid supercapacitors based on Ni(OH)2-Co2(OH)3Cl bilayer nanocomposites and chitosan-derived biomass carbon exhibit high energy density of 37.6 W h kg−1 at power density of 257.8 W kg−1 and 98.21% capacity retention rate after 10,000 charge-discharge cycles. Meanwhile, a mini fan and the “heart” composed of ten LEDs can be easily powered by two tandem hybrid supercapacitors. Hence, it is anticipated that the Ni(OH)2-Co2(OH)3Cl bilayer nanocomposites are the promising materials for hybrid supercapacitors in the future.

Hierarchically porous bowknot-like sodium doped Ni2P2O7-Co2P2O7 structures have been successfully prepared via a hydrothermal route using sodium tartaric as guiding reagent and subsequent calcination in air. The bowknot-like sodium doped Ni2P2O7-Co2P2O7 possesses porous characteristics building of nanoparticles. These bowknot-like sodium doped Ni2P2O7-Co2P2O7 have surface area of 45.32 m2 g−1. The unique porous bowknot-like structures can promote the contacting area between electrode materials and electrolyte, and provide rich channels for ions and electrons transport. Electrochemical measurements reveal that the bowknot-like sodium doped Ni2P2O7-Co2P2O7 exhibit a specific capacity of 295.2 C g−1 at 2.0 A g−1, and excellent cycling performances with 98.8% initial capacity retention after 2000 continuous cycles. Moreover, an asymmetric supercapacitor device was assembled by utilizing the sodium doped Ni2P2O7-Co2P2O7 and activated carbon as cathode and anode, respectively. The device delivers a high energy density of 54.1 Wh kg−1 at a power density of 1700 W kg−1. Impressively, the energy density can still reach up to 35.7 Wh kg−1 at 6778.5 W kg−1. These remarkable electrochemical performances demonstrate that the bowknot-like sodium doped Ni2P2O7-Co2P2O7 are promising electrode material for supercapacitors.

Electrode materials with complex hollow architectures, large specific surface area, and porosity as well as more inner cavities are widely employed for high-performance supercapacitors. In the current work, we report a simple self-templating strategy to prepare a complex nickel cobalt manganese sulfide yolk–shell hollow sphere. Uniform nickel cobalt manganese glycerate solid spheres are first prepared as the template and subsequently transformed into nickel cobalt manganese sulfide yolk–shell hollow spheres by a sulfidation process. When utilized as electrode materials for electrochemical supercapacitors, the resultant nickel cobalt manganese sulfide yolk–shell hollow spheres exhibited a large specific capacitance of 1360 F g−1 at 1.0 A g−1 and superior rate capability. Furthermore, an asymmetric supercapacitor device was assembled using the nickel cobalt manganese sulfide yolk–shell hollow spheres and activated carbon. The device showed a high energy density of 49.8 W h kg−1 at a power density of 1700 W kg−1 and long-term cycling life (only 1.8% loss after 6000 cycles), suggesting their potential application in high-performance electrochemical energy storage.

In this paper, nitrogen doped ZnO/Carbon hollow rhombic dodecahedral is successfully synthesized via an effective self-template way, which includes the synthesis of self-template Zn-based zeolitic imidazolate frameworks and then calcinations in nitrogen atmosphere. The as-synthesized nitrogen doped ZnO/Carbon hollow rhombic dodecahedral shows large specific surface area (534.1 m2 g−1) and porous. In view of its unique structure, large specific surface area, porous and chemical compositions, applying as photoelectrochemical sensing material for determination glutathione, it demonstrates that the nitrogen doped ZnO/Carbon hollow rhombic dodecahedral produces a wide linear determination range (10–1200 μM), high selectivity and low detection limit (8.0 μM). Results in our work suggest that nitrogen doped ZnO/Carbon hollow rhombic dodecahedral is a promising photoelectrochemical sensing material for detection of glutathione. More importantly, the current synthesis route provides a simple and versatile method for preparation of nitrogen doped hollow structured materials deriving from metal-organic frameworks.

In this work, ZnCo2S4 nanospheres in a hollow core-shell structure are synthesized by a facile self-template route. The synthesis route involves a solvothermal method synthesis of Zn-Co precursor solid spheres in glycerol and isopropanol and then sulfidation to obtain hollow ZnCo2S4 core-shell nanospheres. The synthesized obtain hollow ZnCo2S4 core-shell nanospheres possess mesoporous texture and its specific surface area is as large as 117.3 m2 g−1. Benefiting from the remarkable advantages such as novel hollow core-shell structures, mesoporous and large specific surface area, these ZnCo2S4 as electrode material exhibit a specific capacitance of 1045.3 F g−1 at 2.0 A g−1 and superior long-term cycling performance (around 4.5% loss after 5000 continuous cycling). Moreover, an asymmetric supercapacitor assembled with hollow ZnCo2S4 core-shell nanospheres and activated carbon delivers the energy density of 51.7 Wh kg−1 at a power density of 1700 W kg−1. Even at 6800 W kg−1, the energy density can still reach 42.5 Wh kg−1. This work not only demonstrates hollow ZnCo2S4 core-shell nanospheres utilized as a promising candidate for supercapacitors, but also provides a simple and cost-effective strategy for designing and synthesizing other high performance hollow structured metal-sulfides for electrochemical energy storage.

The synthesis of hierarchical nickel cobalt sulfide with core-shelled hollow structures is greatly desired for electrochemical energy storage. Here we report a simple self-template route to synthesize hierarchical NiCo2S4 core-shell hollow spheres. Hierarchical Ni-Co precursor solid spheres are first prepared and utilized as the templates. After a sulfidation process, the solid precursor spheres can be transformed into hierarchical NiCo2S4 hollow spheres with a core-shelled hollow interior. The hierarchical NiCo2S4 core-shell hollow spheres possess a large specific surface area (98.8 m2 g−1) and mesoporous (about 12 nm in sizes) structure. In view of the large specific surface areas, porosities, and novel hollow structures, the hierarchically porous NiCo2S4 core-shell hollow spheres as electrode materials present a high specific capacitance of 1870.2 F g−1 at 2.0 A g−1 and an excellent long-duration cycling performance (about 9% loss after 3000 repeated charging-discharging cycles). Additionally, an asymmetric supercapacitor device using the NiCo2S4 as a positive electrode and activated carbon as a negative electrode is assembled, which delivers an energy density of 52.9 W h kg−1 at power density of 374.9 W kg−1. This work not only suggests the promising electrode materials of the hierarchically porous NiCo2S4 core-shell hollow spheres for application in electrochemical energy storage, but also provides an effective strategy on the metal sulfides design and preparation.

In this work, hierarchical porous NiCo2O4/CeO2 hybrid materials are successfully designed via a facile solvothermal method and subsequent heat treatment, and possess a large specific surface area (113.02 m2 g−1). The hierarchical porous structure and large specific surface area can effectively increase the contact area between the electrode and electrolyte, and also provide rich channels for ion and electron transport. Therefore, when explored as an electrode material in a supercapacitor with KOH and K4[Fe(CN)6] electrolytes, the NiCo2O4/CeO2 hybrid materials show a high specific capacitance of 2659.1 F g−1 at 5.0 A g−1 and excellent cycling performances with 99.6% initial capacity retention after 5000 continuous charge–discharge cycles. Moreover, an asymmetric supercapacitor device was assembled by employing NiCo2O4/CeO2 and activated carbon as a positive and negative electrode, respectively. The device delivers a high energy density of 43.3 W h kg−1 at a power density of 1550 W kg−1. Impressively, the energy density can still reach up to 36.9 W h kg−1 at 4650 W kg−1. These remarkable electrochemical performances demonstrate that the hierarchical porous NiCo2O4/CeO2 hybrid materials are a promising candidate for supercapacitors.

In this work, hybrid porous Co3 O4 -CeO2 hollow polyhedrons have been successfully obtained via a simple cation-exchange route followed by heat treatment. In the synthesis process, ZIF-67 polyhedron frameworks are firstly prepared, which not only serve as a host for the exchanged Ce3+ ions but also act as the template for the synthesis of hybrid porous Co3 O4 -CeO2 hollow polyhedrons. When utilized as electrode materials for supercapacitors, the hybrid porous Co3 O4 -CeO2 hollow polyhedrons delivered a large specific capacitance of 1288.3 F g-1 at 2.5 A g-1 and a remarkable long lifespan cycling stability (

Porous Ni-Co-Mn oxides prisms have been successfully synthesized via a facile route. The process involves the preparation of nickel-cobalt-manganese acetate hydroxide by a simple co-precipitation method and subsequently the thermal treatment. The as-synthesized Ni-Co-Mn oxides prisms had a large surface area (96.53 m2 g−1) and porous structure. As electrode materials for supercapacitors, porous Ni-Co-Mn oxides prisms showed a high specific capacitance of 1623.5 F g−1 at 1.0 A g−1. Moreover, the porous Ni-Co-Mn oxides prisms were also employed as positive electrode materials to assemble flexible solid-state asymmetric supercapacitors. The resulting flexible device had a maximum volumetric energy density (0.885 mW h cm−3) and power density (48.9 mW cm−3). Encouragingly, the flexible device exhibited good cycling stability with only about 2.2% loss after 5000 charge-discharge cycles and excellent mechanical stability. These results indicate that porous Ni-Co-Mn oxides prisms have the promising application in high performance electrochemical energy storage.

Utilizing carbon spheres as templates, a redox etching strategy is designed to convert the carbon spheres into α-MnO2 hollow architectures, which show large surface area of ~70.1 m2 g−1 and mesoporous features. Note that the synthesized α-MnO2 as oxidase can catalyze the oxidization of 3,3′,5,5′-tetramethylbenzidine (TMB), resulting in oxTMB with a characteristic absorption at 652 nm in UV–Vis spectrum. Glutathione (GSH) as antioxidant can be readily oxidized by α-MnO2 and thus the formation of oxTMB is suppressed as GSH introduces. Benefiting from these exciting results, we present an effective colorimetric sensor for GSH based on the synthesized α-MnO2. The special architectures of α-MnO2 endow the colorimetric sensor displaying a wide working range over 0.01 to 15 μM, a determination limit of 4.2 nM as well as significantly selectivity. More importantly, the reported colorimetric sensor exhibits a perfect reliability for GSH in human serum. This work not only explores a simple avenue to synthesis of hollow architectures, but also broadens the biosensing applications of metal oxides.

The charge-trapping memory devices with a structure Pt/Al2O3/(Ta2O5) x (TiO2) 1−x /Al2O3/p-Si (x = 0.9, 0.75, 0.5, 0.25) were fabricated by using rf-sputtering and atomic layer deposition techniques. A special band alignment between (Ta2O5) x (TiO2) 1−x and Si substrate was designed to enhance the memory performance by controlling the composition and dielectric constant of the charge-trapping layer and reducing the difference of the potentials at the bottom of the conduction band between (Ta2O5) x (TiO2) 1−x and Si substrate. The memory device with a composite charge storage layer (Ta2O5) 0.5 (TiO2) 0.5 shows a density of trapped charges 3.84 × 1013/cm2 at ± 12 V, a programming/erasing speed of 1 µs at ± 10 V, a 8% degradation of the memory window at ± 10 V after 104 programming/erasing cycles and a 32% losing of trapped charges after ten years. The difference among the activation energies of the trapped electrons in (Ta2O5) x (TiO2) 1−x CTM devices indicates that the retention characteristics are dominated by the difference of energy level for the trap sites in each TTO CTM device.

In this work, we have successfully developed a simple self-template route for preparation of hollow ellipsoid Ni–Mn sulfides. This route involves the synthesis of solid Ni–Mn ellipsoids via a chemical precipitation method. Then, using thioacetamide (TAA) as the sulfur source, the solid Ni–Mn ellipsoids can be easily converted to hollow ellipsoid Ni–Mn sulfides in ethanol via sulfidation reaction. The as-synthesized hollow ellipsoid Ni–Mn sulfides possess large specific surface areas and porous structures. Benefiting from these structural and compositional advantages, the electrochemical performance of the hollow ellipsoid Ni–Mn sulfides is studied. As expected, the hollow ellipsoid Ni–Mn sulfides show a high specific capacitance of 1636.8 F g−1 at 2.0 A g−1 and good cycling stability (only 4.9% loss after 4000 cycles) as electrode materials for supercapacitors. Furthermore, electrocatalytic oxidation of glucose based on the synthesized hollow ellipsoid Ni–Mn sulfides is also performed. The hollow ellipsoid Ni–Mn sulfides present high sensitivity and selectivity, good stability and a low detection limit (0.02 μM). In addition, the as-synthesized hollow ellipsoid Ni–Mn sulfides exhibit good ability to remove the Congo red dyes from water, which gives them potential application in water treatment. The current work makes a major contribution to the design and preparation of hollow metal sulfide structures, as well as their potential applications in supercapacitors, electrocatalytic oxidation of glucose and water treatment.

Hierarchical hollow structures have been shown excellent performance in supercapacitors. Herein, hierarchical Ni-Mn hydroxide hollow spheres are successfully prepared by an etching strategy. NiMn-glycerate solid spheres are first obtained as templates. After treatment in the mixed solvents of 1-methyl-2-pyrrolidone and water, NiMn-glycerate templates are etched to form hierarchical Ni-Mn hydroxide hollow spheres. Owing to the advantages of hierarchical hollow structures and large surface area, Ni-Mn hydroxide as electrode material manifests a specific capacity of 1680 F g−1 at 2.0 A g−1, and it maintains 1068 F g−1 at 15 A g−1. Meanwhile, a diminished specific capacity of only 3.4 % is achieved over 5500 cycles at 10 A g−1. Furthermore, the fabricated asymmetric supercapacitor comprising of Ni-Mn hydroxide and activated carbon demonstrates a specific energy of 42.8 Wh kg−1 at 1703 W kg−1, indicating as a promising electrode material for high performance supercapacitors.

Mesoporous hierarchical ZnS@β-Ni(OH)2 microspheres have been successfully synthesized via a facile route. In the synthesis process, ZnS spheres are used as the templates for the direct growth of β-Ni(OH)2 nanosheets on their surface. Owing to their unique structure and composition, when the mesoporous hierarchical ZnS@β-Ni(OH)2 microspheres were utilized as electrode materials for supercapacitors, which exhibited substantially enhanced specific capacitance (1361.7 F g−1 at 4.0 A g−1) compared with ZnS and β-Ni(OH)2. Furthermore, a flexible solid state hybrid supercapacitor was assembled by using mesoporous hierarchical ZnS@β-Ni(OH)2 microspheres as a positive electrode and activated carbon as a negative electrode. The resulting flexible solid state device showed a specific capacitance of 170.97 mF cm−2 at 2.0 mA cm−2, and offered a volumetric energy density of 0.783 mW h cm−3 and a power density of 45.7 mW cm−3. Impressively, the device displayed good mechanical flexibility under various bending angles from 0° to 180°. This study presents a novel and promising electrochemically active material for supercapacitors.

A simple hydrothermal method has been developed to prepare hexagonal tablet precursors, which are then transformed into porous sodium-doped Ni2P2O7 hexagonal tablets by a simple calcination method. The obtained samples were evaluated as electrode materials for supercapacitors. Electrochemical measurements show that the electrode based on the porous sodium-doped Ni2P2O7 hexagonal tablets exhibits a specific capacitance of 557.7 F g(-1) at a current density of 1.2 A g(-1) . Furthermore, the porous sodium-doped Ni2P2O7 hexagonal tablets were successfully used to construct flexible solid-state hybrid supercapacitors. The device is highly flexible and achieves a maximum energy density of 23.4 Wh kg(-1) and a good cycling stability after 5000 cycles, which confirms that the porous sodium-doped Ni2P2 O7 hexagonal tablets are promising active materials for flexible supercapacitors.

A template-free hydrothermal method is developed to prepare hierarchical hollow precursors. An inside-out Ostwald ripening mechanism is proposed to explain the formation of the hollow structure. After the calcination in the air, hierarchically meso/macroporous NaCoPO4–Co3O4 hollow microspheres can easily be obtained. When being evaluated as electrode materials for a supercapacitor, the hierarchically porous NaCoPO4–Co3O4 hollow microspheres electrode shows a specific capacitance of 268 F g−1 at 0.8 A g−1 and offers a good cycle life. More importantly, the obtained materials are successfully applied to fabricate flexible solid-state asymmetric supercapacitors. The device exhibits a specific capacitance of 28.6 mF cm−2 at 0.1 mA cm−2, a good cycling stability with only 5.5% loss of capacitance after 5000 cycles, and good mechanical flexibility under different bending angles, which confirms that the hierarchically porous NaCoPO4–Co3O4 hollow microspheres are promising active materials for the flexible supercapacitor.

NiS2 hollow spheres are successfully prepared by a one-step template free method. Meanwhile, α-NiS hollow spheres can also be synthesized via the calcination of the pre-obtained NiS2 hollow spheres at 400 °C for 1 h in air. The electrochemical performances of the as-prepared NiS2 and α-NiS hollow sphere products are evaluated. When used for supercapacitors, compared with NiS2 hollow spheres, the α-NiS hollow sphere electrode shows a large specific capacitance of 717.3 F g(-1) at 0.6 A g(-1) and a good cycle life. Furthermore, NiS2 and α-NiS hollow spheres are successfully applied to fabricate non-enzymatic glucose sensors. In particular, the α-NiS hollow spheres exhibit good catalytic activity for the oxidation of glucose, a fast amperometric response time of less than 5 s, and the detection limit is estimated to be 0.08 μM. More importantly, compared with other normally co-existing interfering species, such as ascorbic acid, uric acid and dopamine, the electrode modified with α-NiS hollow spheres shows good selectivity. Moreover, the α-NiS hollow spheres also present good capacity to remove Congo red organic pollutants from wastewater by their surface adsorption ability.

Hierarchically porous NaCoPO4–Co3O4 hollow microspheres are successfully synthesized via a simple hydrothermal method and calcination in air. It is found that the as-prepared hierarchically porous NaCoPO4–Co3O4 hollow microspheres exhibit good catalytic activity for the oxidation of glucose, shows a fast amperometric response time of less than 5 s, and the detection limit is estimated to be 0.125 μM. More importantly, compared with other normally co-existing electroactive species (such as ascorbic acid, uric acid and dopamine), the electrode modified with hierarchically porous NaCoPO4–Co3O4 hollow microspheres shows good selectivity. These results suggest that hierarchically porous NaCoPO4–Co3O4 hollow microspheres have promising application as electrocatalysts for quantitative determination of glucose with high sensitivity and selectivity.

Mesoporous ZnS-NiS composites are prepared via ion- exchange reactions using ZnS as the precursor. The prepared mesoporous ZnS-NiS composite materials have large surface areas (137.9 m(2) g(-1)) compared with the ZnS precursor. More importantly, the application of these mesoporous ZnS-NiS composites as nonenzymatic glucose sensors was successfully explored. Electrochemical sensors based on mesoporous ZnS-NiS composites exhibit a high selectivity and a low detection limit (0.125 μm) toward the oxidation of glucose, which can mainly be attributed to the morphological characteristics of the mesoporous structure with high specific surface area and a rational composition of the two constituents. In addition, the mesoporous ZnS-NiS composites coated on the surface of electrodes can be used to modify the mass transport regime, and this alteration can, in favorable circumstances, facilitate the amperometric discrimination between species. These results suggest that such mesoporous ZnS-NiS composites are promising materials for nonenzymatic glucose sensors.

Invited for this month′s cover is Prof. Huan Pang from Anyang Normal University. The image represents a non-enzymatic amperometric sensor detecting H2O2. The sensor was fabricated and investigated for the detection of both H2O2 and glucose oxidation. It is revealed that the as-prepared sensor based on N-doped nanoporous carbon–copper nanohybrid plates has a high sensitivity, low detection limit, and excellent selectivity. Read the full text of the article at 10.1002/celc.201300211.

3D ZnO–NiO mesoporous architectures were synthesized through annealing the zinc hydroxide carbonate–nickel hydroxide carbonate composite precursor, which was prepared via a one-pot hydrothermal route. More importantly, we successfully explore the application of the 3D ZnO–NiO composite mesoporous architectures as electrochemical capacitors. Electrochemical study presented that the as-prepared 3D ZnO–NiO composites under different annealing conditions have different electrochemical supercapacitor properties. The as-synthesized sample obtained at 400 °C shows a high specific capacitance of 2498 F g−1 at a current density of 2.6 A g−1, a good rate capability at high current densities and an excellent long-term cycling stability (about 3.0% loss of the maximum specific capacitance after 2000 cycles), which are mainly attributed to its morphological characteristics of mesoporous and nanosheet self-assembling architectures, as well as a rational composition of the two constituents. These results suggest that such 3D ZnO–NiO mesoporous architectures are promising materials for supercapacitors.

Nickel phosphite (Ni11(HPO3)8(OH)6) superstructures assembled by nanotubes are synthesized under mild hydrothermal conditions with the sodium salt of polystyrene sulfonic acid. More importantly, Ni11(HPO3)8(OH)6 superstructures are applied as electrode materials for supercapacitors. Benefitting from their novel superstructures, in a three-electrode system, Ni11(HPO3)8(OH)6 superstructure electrodes show a good specific capacitance (1876 F g−1 at 0.625 A g−1), good rate capability, and excellent cycling properties (95 % of the initial specific capacitance at 6.25 A g−1 after 2000 cycles) in 3.0 M KOH. Additionally, asymmetric Ni11(HPO3)8(OH)6–graphene nanosheet supercapacitors are also designed. The specific energy of a cell in 3.0 M KOH reaches about 28.6 Wh kg−1 at 92.5 W kg−1.

Mesoporous hybrid NiOx-MnOx nanoprisms have been successfully prepared in this work. The synthesis process involves a facile solvothermal method for preparation of Ni-Mn precursor particles and a subsequent annealing treatment. These mesoporous hybrid NiOx-MnOx nanoprisms have a high surface area of 101.6 m(2) g(-1). When evaluated as electrode materials in supercapacitors, the as-prepared mesoporous hybrid NiOx-MnOx nanoprisms deliver a specific capacitance of 1218 F g(-1) at a current density of 2.0 A g(-1). More importantly, the mesoporous hybrid NiOx-MnOx nanoprisms were successfully used to construct flexible solid-state asymmetric supercapacitors. The device shows a specific capacitance of 149.1 mF cm(-2) at 2.0 mA cm(-2), a good cycling stability with only 2.9% loss of capacitance after 5000 charge-discharge cycles, and good mechanical flexibility under different bending angles. These results support the promising application of mesoporous hybrid NiOx-MnOx nanoprisms as advanced supercapacitor materials.

We successfully controlled the crystallographic surface of ZnSn(OH)(6) crystals and systematically obtained ZnSn(OH)(6) crystals in different shapes including cubes, truncated cubes, cuboctahedrons, truncated octahedrons, and octahedrons using a simple solvothermal method in a methylcellulose (MC) ethanol/water solution. By simply adjusting the amount of the NaOH solution added to the reaction system, we observed the shape evolution of ZnSn(OH)(6) particles from cube to octahedron, with the sizes gradually increasing from about 200 nm to 1-2 μm. These results not only provide ZnSn(OH)(6) polyhedra bound by different lattice planes, but also make it possible to investigate the morphology-property relationship of ZnSn(OH)(6) particles with different morphologies obtained under similar conditions. The antibacterial activities of the as-prepared ZnSn(OH)(6) polyhedral particles were studied. It was found that the antibacterial activities of ZnSn(OH)(6) particles against Escherichia coli depend on the shape of the ZnSn(OH)(6) particles, demonstrating that the surface structure of nanocrystals affects the antibacterial activity. Additionally, the obtained ZnSn(OH)(6) polyhedra can be applied as precursors for Zn(2)SnO(4)/SnO(2) composites with different morphologies by calcining at 600 °C.

Parameters such as temperature, time and presence or absence of microwaves affected the particle size and magnetic properties of synthetic magnetite. The presence of microwaves during crystallization significantly increased the particle size of magnetite in a short time with improved magnetic properties. Magnetite samples were characterized by X-ray diffraction, transmission electron microscopy (TEM) and saturation magnetization measurements. The TEM crystal sizes varied from about 40 to 50 nm at room temperature to greater than 50 nm with wider crystal size distribution at higher temperatures. The saturation magnetization values of synthetic magnetites ranged from 57.4 to 89.0 emu/g.

Mono-dispersive hierarchical NiO and Ni/C microspheres were synthesized through a precursor method. The uniform coordination precursor microspheres were easily obtained by treating nickel acetate in methanol under solvothermal conditions. After the precursor was calcined in the air or nitrogen, two kinds of Ni-based nanostructures, NiO and Ni/C can be obtained, respectively. Both the Ni-based nanostructures are uniform mono-dispersive microspheres as the parent precursor and have hierarchical structures assembled by NiO and Ni nanoparticles. The hierarchical NiO and Ni/C microspheres were verified to have good catalytic activities for the propellant combustion of ammonium perchlorate.

A facile and friendly environmental route has been developed to prepare one-dimensional β-FeOOH nanorods without any template at low temperature. In the present reaction system, FeCl 3 6H 2 O was used as a single iron precursor. Effects of different experimental conditions on morphology and polymorph of the as-prepared samples were studied. Compared with the urea, the concentration of FeCl 3 influenced evidently the length of the as-formed β-FeOOH nanorods. The aspect ratio of the sample was adjusted from 6 to 24 by changing the concentration of FeCl 3 . When the experimental temperature increased from 70 to 80 °C, the morphology of the resulting β-FeOOH changed from spindle to rod. The influences of different kinds of electrolytes on the final products were also studied. The results demonstrated that different electrolytes (KCl, KSCN, NaNO 3 and NH 4 Cl) can strongly influence the sizes and structures of the as-prepared samples. Compared with various surfactants, the anionic surfactant, sodium dodecyl sulfate (SDS), affected significantly the morphology and size of the as-prepared samples. Nanoribbon-shaped β-FeOOH was synthesized in the presence of SDS for the first time.

A friendly environmental method was used to prepare a water-based hematite (α-Fe2O3) nanofluid through a simple biomolecule-assisted hydrothermal process. The molar heat capacities of the obtained nanofluids, base fluids, and hematite nanoparticles were measured by a high-precision automatic adiabatic calorimeter over the temperature range of (290 to 335) K, respectively. Polynomial equations of the molar heat capacities as a function of temperature were fitted by a least-squares method for the solid and nanofluid samples. Smoothed heat capacities and thermodynamic functions of the obtained samples, such as H(T/K) − H(298.15 K) and S(T/K) − S(298.15 K), were calculated on the basis of the fitted polynomials and the relationships of the thermodynamic functions. On the basis of the as-obtained molar heat capacities, the excess heat capacities of the nanofluids were calculated. These excess heat capacities reveal that the stable hematite nanofluids exhibit unique properties compared with the unstable one.

Different morphologies of beta-FeOOH including rod- and spindle-shaped crystals were synthesized via a hydrothermal reaction at low temperature. The molar heat capacities of the obtained samples were determined by a precision automated adiabatic calorimeter over the temperature range of (78 to 390) K. The observed results demonstrated that the change of the molar heat capacity with thermodynamic temperature was different for the rod and spindle-shaped beta-FeOOH crystals. Polynomial equations of the molar heat capacities as a function of temperature were fitted by a least-squares method for the rod- and spindle-shaped beta-FeOOH crystals. Smoothed heat capacities and thermodynamic functions of the obtained samples, such as H(T/K) - H(298.15) and S(T/K) - S(298.15), were Calculated on the basis of the fitted polynomials and the relationships of the thermodynamic functions. In addition, the as-prepared samples were also characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), and thermal gravimetric analysis (TGA).

A novel and facile method for preparation of stable nanofluid is introduced, in which fecl(3)center dot 6h(2)o and urea were used as reactants without any surfactants. the obtained solid sample was proved to be beta-feooh by xrd technology and spindle-shaped by tem technology. the coexisting nh(3) molecules may be the main reason for the stable nanofluid. the weak bonding between nitrogen and iron atoms would be formed. the investigation on the excess heat capacity of the obtained nanofluid sustains this opinion. the heat capacities of the obtained beta-feooh particles and the nanofluid were determined by an adiabatic calorimeter. and these obtained results will help the applications of beta-feooh and the nanofluid to industry, and the establishment of the model of thermal conductivity of nanofluid. the thermodynamic properties of the obtained beta-feooh particles and the nanofluid were calculated based on the obtained functions of heat capacity with respective to thermodynamic temperature and the relationships between the thermodynamic properties.

A kind of monodisperse core–shell structure of spherical silica at nanocrystalline copper has been successfully synthesized by a two-step synthesis method. A uniform spherical particle of silica was firstly fabricated according to the Stober method. The obtained silica sample was coated by nanocrystalline copper through oxidation–reduction process. The effects of the volume of water added in the reaction system on particle size of silica were investigated. The particle size of the as-synthesized silica changed from about 170 ± 2 to 160 ± 2 nm with the volume of the added water change from 2.3 to 20 ml. When the volume of the added water was changed to 40 ml, the diameter of the obtained silica particle was about 210 ± 5 nm. The thickness of the coated copper can be controlled by using different sizes of silica particle. The formation mechanism was also discussed.

Low-temperature molar heat capacities of the carbon nanotubes (CNTs) including single-walled carbon nanotubes (SWNTs) and multiwalled carbon nanotubes (MWNTs) were measured, respectively, by a precision automated adiabatic calorimeter over the temperature range of (78 to 398) K. The observed results demonstrated that the change in the molar heat capacity with thermodynamic temperature was different for the SWNTs and the MWNTs. Polynomial equations of the molar heat capacities as a function of the temperature were fitted by the least-squares method for SWNTs and MWNTs, respectively. Smoothed heat capacities and the changes in thermodynamic functions of the CNTs, such as ΔH = H(T/K) − H(298.15) and ΔS = S(T/K) − S(298.15), were calculated on the basis of the fitted polynomials and the relationships of the thermodynamic functions.

Copper sulfides, such as Cu7S4, Cu1.8S, Cu1.81S and Cu2S, in the wire-like, and solid and hollow ball-like shapes congregated from nano-spherical particles and nanoslices, have been prepared by a solvothermal method using a mixture of water and ethylene glycol as solvent. CuSO4 and thiourea were used as the starting materials without assistance of any surfactant or template. The results show that the water content in the solvent affects the morphology of the samples, and the reaction time and temperature affect the crystal structure and morphology. On the basis of the obtained results, the formation processes of different morphologies of copper sulfides can be interpreted by the following mechanism: nanoparticles of copper sulfides initially formed, then the wire-like structures were gradually created, and finally translated to solid and hollow spherical structures under the different experimental conditions.

Three-dimensional (3D) honeycomb-like birnessite networks composed of ultrathin two-dimensional (2D) nanosheets were firstly synthesized through a facile and low-cost synthetic route. By using carbon microspheres as a template instead of graphene, hierarchical birnessite structures assembled by ultrathin nanosheets including york–shell and hollow structures were obtained besides the ultrathin birnessite nanosheets with a thickness of about 0.7 nm. By assembling carbon spheres into an ordered 3D array, novel 3D honeycomb-like birnessite structures assembled by ultrathin nanosheets were firstly prepared. When evaluated as an anode material for Li-ion batteries, the 3D honeycomb-like networks show enhanced electrochemical performances with high capacities, excellent cycling stability and good rate capability, which can be ascribed to the novel 3D honeycomb-like macroporous structure with a 3D inverse opal structure, well-ordered macropores, interconnected walls and a regular periodicity.

α-NiS and β-NiS hollow spheres were successfully synthesized via the Kirkendall effect under different hydrothermal conditions. The obtained α-NiS and β-NiS hollow spheres were evaluated as electrode materials for supercapacitors. Importantly, the α-NiS hollow sphere electrode has a large specific capacitance (562.3 F g(-1) at 0.60 A g(-1)) and good cycling property (maintaining about 97.5% at 2.4 A g(-1) after 1000 cycles). Furthermore, the as-prepared α-NiS and β-NiS hollow spheres were successfully applied to construct electrochemical glucose sensors. Especially, the α-NiS hollow spheres exhibit a good sensitivity (155 μA mM(-1) cm(-2)), low detection limit (0.125 μM), and a wide linear range.

A bottom-up-then-up-down route was proposed to construct multi-level Bi2S3 hierarchical architectures assembled by two-dimensional (2D) Bi2S3 sheet-like networks. BiOCOOH hollow spheres and flower-like structures, which are both assembled by 2D BiOCOOH nanosheets, were prepared first by a “bottom-up” route through a “quasi-emulsion” mechanism. Then the BiOCOOH hierarchical structures were transferred to hierarchical Bi2S3 architectures through an “up-down” route by an ion exchange method. The obtained Bi2S3 nanostructures remain hollow-spherical and flower-like structures of the precursors but the constructing blocks are changed to 2D sheet-like networks interweaving by Bi2S3 nanowires. The close matching of crystal lattices between Bi2S3 and BiOCOOH was believed to be the key reason for the topotactic transformation from BiOCOOH nanosheets to 2D Bi2S3 sheet-like nanowire networks. Magnetism studies reveal that unlike diamagnetism of comparative Bi2S3 nanostructures, the obtained multi-level Bi2S3 structures display S-type hysteresis and ferromagnetism at low field which might result from ordered structure of 2D networks.

3D hierarchical CdS mesoporous nanosheets are prepared via a facile hydrothermal method in the presence of soulcarboxymthyi chitosan. By investigation of various reaction parameters, it is demonstrated that the reaction temperature and the amounts of ammonia, thiourea and Cd(NO3)2 play important roles in the formation of 3D hierarchical CdS. The optical properties of 3D hierarchical CdS are investigated using ultraviolet-visible (UV-vis) spectroscopy. A photocatalytic activity experiment reveals that the as-synthesized 3D hierarchical CdS exhibits an excellent photocatalytic performance for the degradation of aqueous solutions of methyl orange (MO) under visible light illumination, suggesting that the 3D hierarchical CdS nanomaterial might be a promising candidate for treatment of organic pollutants in waste water.

ZnO materials with a range of different morphologies have been successfully synthesized via a simple double-solvothermal method in the presence of glycine. The morphologies of the products can be controlled from superstructures to microrods by adjusting the amount of water in the EtOH/H2O system. Photoluminescence (PL) studies reveal that the more amount of water was used, the stronger PL relative intensity of the green emission is, but the weaker ultraviolet emission. This might be attributed to the more defects of the products when the more water was used. The catalytic studies show that all the samples have good abilities to decrease decomposition temperature around 300°C and the decomposition temperature lowers with the increase of the relative intensity of ZnO green emission.

Conventional crystalline β-MnO2 usually exhibits poor electrochemical activities due to the narrow tunnels in its rutile-type structure. In this study, we synthesized a novel 2D β-MnO2 network with long-range order assembled by β-MnO2 nanowires and demonstrated that the novel 2D β-MnO2 network exhibits enhanced electrochemical performances. The 2D network is interwoven by crossed uniform β-MnO2 nanowires and the angle between the adjacent nanowires is about 60°. Such a novel structure makes efficient contact of β-MnO2 with electrolyte during the electrochemical process, decreases the polarization of the electrode and thus increases the discharge capacity and high-rate capability. The specific capacitance of the obtained 2D β-MnO2 network is 453.0 F/g at a current density of 0.5 A/g.