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The development of active, low-cost and durable bifunctional electrocatalysts toward both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) are important for overall water splitting. Here, well-defined arrays of vanadium-iron bimetal organic frameworks (VFe-MOF) with controllable stoichiometry have been successfully prepared on nickel foam (NF). The as-fabricated VFe-MOF@NF electrode exhibits excellent electrocatalytic activity and durability for OER and HER in alkaline medium. The material’s overpotentials of 10 mA/cm2 are 246 mV for OER and 147 mV for HER, respectively. The electrolyzer made from the VFe-MOF@NF electrodes as both the cathode and anode in 1 mol/L KOH needs only a voltage of 1.61 V to reach a current density of 10 mA/cm2. The superior performance of VFe-MOF@NF can be attributed to the morphological control and electronic regulation of the bimetals, that is, 1) the exposure of the active sites at electrocatalyst/electrolyte interfaces due to the array structure; 2) the synergistic effect of vanadium and iron metals on electro-catalyzing the overall water splitting.

Large-scale distributed thermal storage requires high-energy-density and low-cost thermal storage materials. Here, a concocted composite composed of Al2(SO4)3·18H2O and FeSO4·7H2O salts, as well as...

Porous carbons are always proposed as electrode materials of lithium-ion batteries (LIBs); however, their high porosity and large surface areas lead to severe side reactions with electrolytes. Here, a new kind of non-nanopore carbon was designed for the anode material of LIBs. It was prepared from catalytic synthesis of a porous carbon from coal followed with graphitization. The graphitization removes the micro/mesopores of the porous carbon, and creates a new kind of carbon with very limited porosity and defects, which can evade side reactions with electrolytes. The resultant structure of the material can facilitate ion transport, provide a good conductivity, and alleviate the stresses experienced in repeated charge/discharge. The material exhibits excellent lithium-storage properties, including a high reversible capacity of 347 mAh g−1 and high cycling stability (no capacity fading during 1000 cycles). The material might be an alternative to artificial graphite considering its facile preparation and excellent performance.

Carbon-based composites are the most promising anode materials for sodium-ion batteries (SIBs), due to the sustainability and high electronic conductivity. However, the poor dynamics of SIBs limit the practical application of carbon materials. Herein, the nitrogen doped three-dimensional porous carbons (NPC) with expanded graphitic interlayer space (0.37 nm) was prepared by a hard MgO template assisted method through using zero-cost asphalt powder as precursors and low-cost urea as an additional nitrogen source. The unique structure of NPC is not only conducive to the increase of reversible capacity, but also to accelerate the diffusion of Na+, enabling the NPC anode with rapid capacitive sodium storage. The NPC-based electrode delivers a high reversible capacity (352.7 mAh g−1 at 0.2 A g−1), cycle life (with 99% at 5.0 A g−1 for 900 cycles) and diffusion rate of Na+ (1.66 × 10−9 and 3.78 × 10−9 cm2 s−1 for anodic and cathodic, respectively). Furthermore, the NPC is prepared via a one-step low-cost process, suggesting a prospective development of carbon-based anode materials for SIBs.

The large-scale burning of coal has led to increasingly serious SO

Electrochromic materials hold great promise in energy-saving windows of buildings and various functional glasses. When constructing a private space, it is difficult for electrochromic materials to ...

Structural and compositional modulation of low-cost hydroxide is important for making efficient electrocatalysts of the oxygen evolution reaction (OER), and it is an ongoing challenge. Here, Ni-Fe-W hydroxide complex by incorporation of tungsten into nickel-iron layered double hydroxide was proposed and investigated. As-formed Ni-Fe-W hydroxide nanosheets are highly porous and self-supported on the carbon fiber substrates, which promote the exposure of the active metal sites for significantly enhanced OER activity. Moreover, the as-introduced tungsten is evidenced to be in a W6+ oxidation state which can facilitate charge transfer and electron capture and thereby decrease the critical conversion barrier of the absorbed OH- to O radical in OER. A series of Ni-Fe-W hydroxides were prepared, with the best molar ratio of Ni-Fe-W sources being 6:2:1. The optimal Ni6Fe2W-LDH@carbon fiber electrode delivers a low overpotential of 264 mV at 10 mA cm-2 and high stability (only 1.6% of the potential increase after 10 h) in alkaline electrolyte. Moreover, the structure of the constructed Ni-Fe-W hydroxide is evidenced to be stable and important for the electrocatalytically stable. The study is expected to open a new avenue in developing multiple hydroxides for low-cost and efficient electrocatalysts.

One critical problem of metal–organic frameworks (MOFs) limiting their applications lies in the inherent instability of the frameworks constructed by the metals ions and organic ligands, which can ...

In order to achieve a high rate silicon (Si) anode for lithium-ion batteries, a nanostructured Si@C@CNT composite with multistage conductive networks and interpenetrating voids is designed and fabricated by a spray drying approach, which could obviously improve the electronic/ionic conductivity, and effectively release the strain generated during Li+ intercalation/de-intercalation into/from Si, thereby leading to a high-rate (620 mA h g−1 at 7.5 A g−1) and stable Si anode. For actual applications, Si@C@CNT-PG (porous graphene) electrode has been built by simple mixing of the Si@C@CNT nanocomposite and home-made PG at the weight ratio of 2:8 as the active material, which exhibits the overwhelming electrochemical performances: the reversible capacity reaches 600 mAh g−1 at 4 A g−1; moreover, 80% of the initial capacity is still attained after charge/discharge at 800 mA g−1 for 200 times.

It is a great challenge to engineer thick or bulk electrodes with well-maintained rate performance, since their charge-transport kinetics are severely worsened at large current densities. Here, hig...

Seeking new applications of carbon nanotubes (CNTs) will be important since large-scale production has made them available in many applications. Herein, aggregated CNTs (A-CNTs) with interwoven pores were prepared for shape-stabilized phase change materials (PCMs). Owning to the capillary force from the pores, paraffin was readily encapsulated into A-CNTs, and formed a new kind of shape-stabilized PCMs. As-prepared paraffin/A-CNT composites had optimal paraffin loading approaching 88 wt % and offered a storage capacity of 172.14 J g–1 that exceeded the vale based on mixing rule. To confirm the structure effectiveness, A-CNTs were dispersed into random nanotubes; as-formed composite PCMs displayed obviously reduced loading and storage capacities. The enhanced performance was ascribed to the effective encapsulation of paraffin in the interwoven pores of A-CNTs. Moreover, the composites with improved thermal conductivities were attained and displayed enhanced thermal-storage response. The results indicated t...

Synthesis of high-performance electrocatalysts is significant for energy conversions. The oxygen evolution reaction (OER) is a fundamental process in such energy conversions. Here, we first report the synthesis of NiFe-bimetal two-dimensional (2D) ultrathin metal-organic frameworks (MOFs) nanosheets (NiFe-UMNs) with a uniform thickness of ~10 nm, which show excellent catalytic activity for OER in alkaline conditions. The as-prepared NiFe-UMNs can deliver the current density of 10 mA cm−2 at a low overpotential of 260 mV. Moreover, NiFe-UMNs possess by far the lowest Tafel slope of 30 mV dec−1 for OER. The high-performance activity is the result of abundant surface coordinatively unsaturated metal atoms, as well as the addition of Fe that is also crucial to enhance the activity.

Hollow porous Fe2O3 hexagonal nanorods were fabricated via a facile and controllable approach using MOFs (Fe-MIL-88A) as both precursors and sacrificial templates. It has been found that Fe(OH)3, which is formed on the surface of MOFs after treatment with NaOH solution, plays a significant role in maintaining its morphology during calcination. The interior of well-defined hollow porous Fe2O3 hexagonal nanorod structures is assembled by interconnected nanoparticles to form a porous structure. As anode materials for Li-ion batteries, the hollow porous Fe2O3 hexagonal nanorods exhibit long-term cycling stability (1219 mA h g−1 after 100 cycles) and ultrahigh rate capability. The high electrochemical performance is attributed to the unique structure and morphology of the hollow porous nanorods.

The peony-like CuO micro/nanostructures were fabricated by a facile hydrothermal approach. The peony-like CuO micro/nanostructures about 3 –5 μm in diameter were assembled by CuO nanoplates. These CuO nanoplates, as the building block, were self-assembled into multilayer structures under the action of ethidene diamine, and then grew into uniform peony-like CuO architecture. The novel peony-like CuO micro/nanostructures exhibit a high cycling stability and improved rate capability. The peony-like CuO micro/nanostructures electrodes show a high reversible capacity of 456 mAh/g after 200 cycles, much higher than that of the commercial CuO nanocrystals at a current 0.1 C. The excellent electrochemical performance of peony-like CuO micro/nanostructures might be ascribed to the unique assembly structure, which not only provide large electrode/electrolyte contact area to accelerate the lithiation reaction, but also the interval between the multilayer structures of CuO nanoplates electrode could provide enough interior space to accommodate the volume change during Li+ insertion and de-insertion process.

Inorganic composites with mechanical flexibility are desired in synthesis of advanced materials for multifunctional applications. Here, we demonstrated the synthesis of a lightweight and flexible composite aerogel composed of carbon nanotubes (CNTs) and mesoporous iron oxide (Fe3O4) using an in-situ growth method. CNTs serve as frameworks for the growth of magnetic ferrite nanoparticles; while the growth of the magnetic nanoparticles crosslinks CNTs into an integrated structure. Therefore, mesoporous Fe3O4 particles are threaded by CNTs, leading to formation of the monolithic magnetic foam with a high particle loading of more than 88 wt%. This magnetic foam is highly porous, effective for microwave absorption. Based on the rational combination of Fe3O4 and CNTs, the composite material can offer excellent microwave absorbing performance, particularly in the low-frequency range of 3–5 GHz. Moreover, the porous composite aerogel can be compacted into a flexible magnetic nanopaper. Because of the structure properties, the composite may be used in many other applications such as energy storage, catalyst, and biochemistry.

The hierarchical Cu nanosheets @ CuO nanorods nanostructures were fabricated by a facile hydrothermal approach using Cu nanosheets as self-template and nano-substrate in an aqueous solution of NaOH/H2O2. The hierarchical Cu nanosheets @ CuO nanorods electrodes show a high reversible capacity of 620 mAh/g after 200 cycles, much higher than that of the pure CuO nanocrystals at a current 0.1 C. The excellent electrochemical performance of the hierarchical Cu nanosheets @ CuO nanorods electrode can be attributed to the unique architecture, which not only provides appropriate spaces between nanorod arrays to accommodate the volume change during the discharge/charge process, but also enables fast charge transport owing to the reduced diffusion paths for electrons and induced the Cu nanosheet as the nano-substrates.

Mesoporous carbons with high porosity, large specific surface areas and a certain degree of graphitization were facilely prepared via carbonization of sucrose at different temperatures of 700 °C (C-700), 800 °C (C-800) and 900 °C (C-900) and were used as supporting frameworks for phase change materials (PCMs) loading paraffin. The as-prepared carbons had high loading capacity of paraffin as demonstrated by leakage tests. The paraffin loading capacity of C-700, C-800 and C-900 reached up to 88.8 wt%, 91.7 wt% and 90.6 wt% respectively without leakage, and the corresponding latent heats were 103.0%, 104.5% and 102.9% that of pure paraffin with the same actual paraffin amount, showing improved latent heat. TG results showed that the as-prepared PCMs had better thermal stability and their good thermal cycling stability was demonstrated by thermal cycling tests after 50 cycles. Furthermore, the thermal conductivity of the composite PCMs improved to a certain degree compared with that of pure paraffin.

Composite material of NiO/CNTs consisting of two-dimensional porous NiO nanosheets threaded by carbon nanotubes was prepared by thermal treatment of Ni(OH) 2 /CNTs obtained from an in-situ hydro-thermal method. The introduction of CNTs during the synthesis processes can effectively prevented the aggregations of NiO nanosheets, and form interpenetrated composite structure. Therefore, porous NiO nanoflakes are threaded by CNTs, leading to the formation of the lightweight composite with different NiO loadings. The as-prepared NiO/CNTs composite is highly porous, effective for microwave absorption. The minimum reflection loss reaches −25.4 dB when the NiO loading is 85 wt% with thickness of 2.0 mm at 10 GHz. This composite material is expected to be a promising candidate as microwave absorbing materials.

Sodium-ion batteries (SIBs) are regarded as an ideal alternative to lithium-ion batteries, but the larger radius of Na+ compared with Li+ results in lower energy density, shorter cycle life, and sluggish kinetics of SIBs. Therefore, it is of significant importance to explore appropriate Na+ storage materials with high capacity and fast Na+ transport kinetics. Herein, doublelayered mesoporous graphene nanosheets codoped with oxygen and nitrogen (O,N-MGNSs) were developed as a new cathode material with high Na+ storage capacity and fast ion-transport kinetics for SIBs. The codoping of MGNSs with oxygen and nitrogen by in situ chemical vapor deposition endowed them with a hierarchical porous network, robust structures, good conductivity, and abundant functional groups. The O,N-MGNSs could host Na+ in two ways: surface adsorption and surface redox reaction, and this endowed them with high Na+ storage capacity and fast charging/discharging rates in SIBs. Electrochemical results revealed that the O,N-MGNSs delivered a reversible capacity of 156 mAh g-1 at a current density of 0.5 A g-1 (corresponding to a rate of 3 C) between 1.5 and 4.2 V and exhibited a high cycling stability (95 % capacity retention at 1 A g-1 for more than 1000 cycles).

Self-healing triboelectric nanogenerators (SH-TENGs) with fast self-healing, high output performance, and wearing comfort have wide and promising applications in wearable electronic devices. This work presents a high-performance hydrogel-based SH-TENG, which consists of a high dielectric triboelectric layer (HDTL), a self-healing hydrogel electrode layer (SHEL), and a physical cross-linking layer (PCLL). Carbon nanotubes (CNTs), obtained by a chemical vapor deposition (CVD) method, were added into polydimethylsiloxane (PDMS) to produce the HDTL. Compared with pure PDMS, the short-circuit transferred charge (44 nC) and the open circuit voltage (132 V) are doubled for PDMS with 0.01 wt% CNTs. Glycerin, polydopamine particles (PDAP) and graphene were added to poly (vinyl alcohol) (PVA) to prepare the self-healing hydrogel electrode layer. SHEL can physically self-heal in ~1 min when exposed to air. The self-healing efficiency reaches up to 98%. The PCLL is made of poly(methylhydrosiloxane) (PMHS) and PDMS. It forms a good physical bond between the hydrophilic hydrogel and hydrophobic PDMS layers. The electric output performance of the SH-TENG can reach 94% of the undamaged one in 1 min. The SH-TENG (6 × 6 cm2) exhibits good stability and superior electrical performance, enabling it to power 37 LEDs simultaneously.

Pd/PdO nanoparticles supported on porous graphene (PG) are synthesized by a gas-liquid interfacial plasma method using Pd(NO3)2·2H2O as precursor. The Pd/PdO ratios can be controlled by changing the amount of Pd(NO3)2·2H2O. The synthesized Pd/PdO electrocatalysts exhibit a high electrocatalytic activity for methanol oxidation. The Pd/PdO nanoparticles attached on PG support shows better activity than that on oxidation carbon nanotubes support for methanol oxidation. In addition, our findings show that the PdO present in the Pd nanoparticles can enhance the electrocatalytic activity. It is worth to mention that the Pd/PdO nanoparticles supported on porous graphene catalysts show better electrochemical stability than that of commercial Pd/C catalyst.

We have developed a procedure of shear-assisted supercritical CO2 exfoliation (SSCE) for producing high-quality and large-quantity graphene nanosheets in this work. Supercritical CO2 fluid can diffuse in between the interlayer of graphite due to its high diffusivity and low viscosity. When high-speed shear stress was applied to CO2 fluid, graphite powder was expanded and delaminated effectively into graphene sheets. Our experiments indicate that high temperature and high rotation speed of CO2 fluid accelerate the exfoliation process, consistent with our molecular dynamics simulation results that the shock velocity of CO2 molecules should be large enough for stable separation of graphene layers. It is found that the graphene synthesized by SSCE consists of 90% exfoliated sheets with less than 10 layers and ∼70% between 5 and 8 layers, confirmed by atomic force microscopy and transmission electron microscopy characterizations. The conductivity of graphene is up to 4.7 × 106 S/m, much higher than that of chemically reduced graphene oxide. Therefore, SSCE provides a simple, fast, and economical method of producing large-scale and high-quality graphene.

Nanomaterials with electrochemical activity are always suffering from aggregations, particularly during the high-temperature synthesis processes, which will lead to decreased energy-storage performance. Here, hierarchically structured lithium titanate/nitrogen-doped porous graphene fiber nanocomposites were synthesized by using confined growth of Li4Ti5O12 (LTO) nanoparticles in nitrogen-doped mesoporous graphene fibers (NPGF). NPGFs with uniform pore structure are used as templates for hosting LTO precursors, followed by high-temperature treatment at 800 °C under argon (Ar). LTO nanoparticles with size of several nanometers are successfully synthesized in the mesopores of NPGFs, forming nanostructured LTO/NPGF composite fibers. As an anode material for lithium-ion batteries, such nanocomposite architecture offers effective electron and ion transport, and robust structure. Such nanocomposites in the electrodes delivered a high reversible capacity (164 mAh·g–1 at 0.3 C), excellent rate capability (102 mAh·g–1 at 10 C), and long cycling stability.

Flexible graphite nanoplatelets (GNPs)–copper nanowires (Cu NWs) composites of a sandwich-like structure were prepared by a simple filtration method. Cu NWs were sandwiched between GNPs films (G/NWs/G). The sandwiched structure results in conductivity up to 3.18 × 105 S m−1, higher than the reported graphene based papers and bulk graphite. The performance of the sandwiched papers is further improved to 8.65 × 105 S m−1 through mechanical pressing. Compared to the pure Cu NWs film, the sandwiched composite is oxidation resistant and stable in air, thus promising as candidates for high performance flexible electronics.

Fe3O4 magnetic nanocomposites combined with graphene oxide (GO) and carbon nanotubes (CNTs) are synthesized by a hydrothermal method, followed by synthesis of GO/CNT–Fe3O4 supported Pd nanoparticles using a gas–liquid interfacial plasma (GLIP) method with Pd(OAc)2 as a precursor, and the Pd nanoparticles show a uniform particle size distribution. The catalysts exhibit remarkable catalytic activity during the hydrogenation of nitroarenes under H2 atmosphere at 60 °C in water using a small amount of catalyst, and the catalyst can be magnetically separated from the reaction mixture. The addition of the Fe3O4 component to the GO/CNTs can be used to effectively prevent aggregation and restacking of GO and the CNTs, and the GO/CNT composite can adjust the hydrophilic–hydrophobic property of the catalysts. Furthermore, the Pd catalyst can be readily recovered and reused several times without a significant decrease in activity. It is worth mentioning that the Pd-3 catalysts show remarkable activity during C–H functionalization.

Creating coal-based new materials and finding their new applications are important for sustainable chemistry and engineering of coals. Here, we prepared a new kind of coal-derived three-dimensional graphitic porous carbon (denoted as GPC) for form-stable composite phase change materials. The ultrathin graphitic walls of this material enhanced thermal conductivity and shape stability. This hierarchical porous material exhibits a specific surface area of 1351 m2·g−1, which is rarely achieved in coal-derived carbons. It provides a high loading capacity of solid-liquid phase change materials (e.g., paraffin) with shape stability and high specific thermal storage density. The loaded 90 wt% paraffin@GPC composite achieved a reversible melting enthalpy of 187.4 kJ·kg−1, standing for a 7.8% increase than the theoretical value calculated from the loading amount. In addition, the highly porous GPC provides abundant sites for solidification nucleation of paraffin and therefore obtains high endo-/exo-thermal stability. The thin graphitic walls of GPC render the 90 wt% composite with an enhanced thermal conductivity of 0.58 W·m−1·K−1, which is beneficial to deliver rapid thermal transfer from outside in. The structural and thermal properties of this low-cost coal-based GPC reveal new potential applications for thermal storage.

Rational design of nanostructured metal-organic frameworks (MOFs) for catalytic applications is an ongoing challenge. Here, a new hierarchical NiVFe-MOF composed of self-supported nanowires and nanosheets are first prepared through substrate-assisted solvothermal growth. The MOF nanowires and nanosheets are tightly assembled into an integrated nanostructure with facile mass transfer. At the same time, the microstructure of the nanowires/nanosheets exhibits abundant active sites due to the hierarchical porosity. As resultant NiVFe-MOF exhibits significantly enhanced activity in oxygen evolution reaction (OER). The resulting MOF yields a low overpotential (225 mV, 10 mA cm−2; 269 mV, 100 mA cm−2) and high stability after long-term cycling test, suggesting a state-of-the-art performance. This study can provide new insights on rational design and synthesis of nanostructured MOFs for catalytic applications.

Thermal storage performance of form-stable phase change materials (PCMs) is often compromised by the heavy use of the supporting materials. Here, lightweight mesoporous carbon fibers (MCFs) with continuous graphitic walls are prepared by carbonization of polyvinylidene fluoride on magnesium oxide fibers for form-stable PCMs. The structure of the MCFs are comprehensively investigated to show their merits for supports of the PCMs. The MCFs are rich in relatively ordered mesopores, which can provide effective loading of paraffin and give high thermal storage capacities per unit weight. The paraffin loadings of the as-obtained MCF-700, MCF-800 and MCF-900 reach 93, 90, and 92 wt% with maintained shape stability, and deliver the thermal storage capacities of 176.54, 183.35, and 177.75 kJ kg−1, respectively. Due to the abundant pore networks and the improved interfacial property from the in-situ fluorine doping, the MCFs-supported PCMs exhibit high running stability and thermal storage efficiency in cycling. More importantly, the penetrating graphitic walls of the MCFs provide effective thermal-conductive pathways from outside to the interior for rapid thermal transfer. The results exhibit that the MCFs with interconnected graphitic walls can be an effective support of form-stable phase change materials for solar harvesting, etc.

Nanosheets with large exposed surface and high chemical activity are of paramount significance for catalysis, gas sensing and energy storage. However, assembling them into large-area free-standing films and preventing aggregation of individual nanosheets remain a great challenge. Herein, an efficient strategy is proposed to assemble defect-rich TiO2(B) nanosheets into a 3D-scaffold structured free-standing film, which can preserve high chemical activity and prevent their aggregation. The inherent pores of Teflon lining are employed as load-bearing base to construct 3D scaffolds, and then, a rapid dissolution-recrystallization hydrothermal process is developed to fabricate defect-rich TiO2(B) nanosheets (~5 nm in thickness) on the 3D scaffolds. The numerous defects are crucial for boosting high rate performance within LIBs. The hierarchical 3D-scaffold structure endows the nanosheets-based electrode with outstanding cycling stability (96.1% retention after 6000 cycles at 6.7 A g−1), which hits a record high in terms of capacity retention for TiO2(B) nanosheets at high rate. The strategy for fabricating and assembling defect-rich TiO2(B) nanosheets paves the way for high performance LIBs.

Low conductivity and structural degradation of LiMn2O4 lead to poor power capability and severe capacity fading of hybrid aqueous Zn/LiMn2O4 battery. Here, we propose an effective strategy by tuning the microstructures of graphene to optimize its electrical and interfacial properties and electrode dynamics of LiMn2O4/graphene cathodes, which successfully prompt significant improvements in electrical conductivity and structural stability, thus essentially leading to a promising electrochemical performance. More importantly, it reveals different electrochemical properties prompted by different conductivity, which mainly depends on the microstructures of graphene. This dependence is due to the influence of electronic channels and conductive paths on the conductivity of LiMn2O4/graphene electrodes. A well-designed mesoporous graphene composed of about two graphene-layers exhibits an excellent high-rate performance; even after 300 cycles, a highly reversible capacity of 75 mAh g-1 is retained at 4C rate. The results of this study suggest that the structural tuning of electronic channels of graphene can be used as an effective means to improve the performance of LiMn2O4 cathodes in hybrid aqueous batteries.

We report that the presence of PdO nanoparticles can enhance the catalytic performance of Pd catalyst for the Suzuki reaction in water. Heterogeneous Pd/PdO nanoparticles supported on multi-walled carbon nanotubes (CNTs), weakly oxidized multi-walled carbon nanotubes (WCNTs) and strongly oxidized multi-walled carbon nanotubes (SCNTs) catalysts are synthesized by a one-pot gas-liquid interfacial plasma (GLIP) method using Pd(NO3)(2)center dot 2H(2)O as precursor. Among these synthesized catalysts, the Pd/PdO supported on WCNTs (Pd/PdO/WCNTs) catalyst exhibits the highest catalytic activity during the Suzuki reaction in water. Moreover, the Pd/PdO catalyst shows higher catalytic activity during the Suzuki reaction than Pd catalyst. The as-prepared catalyst displayed remarkable activity toward challenging substrates such as heteroaryl halides and ortho-substituted aryl halides as well as aryl chlorides using low Pd loading in good yields. Since the catalyst exhibits extremely low solubility in organic solvent, the product can be simply extracted with ethyl acetate while the catalyst remained in the aqueous phase. The catalyst can be simply and efficiently used for ten consecutive runs without significant decrease in activity. (C) 2015 Elsevier B.V. All rights reserved.

Nanostructured composites built from ordinary building units have attracted much attention because of their collective properties for critical applications. Herein, we have demonstrated the heteroassembly of carbon nanotubes and oxide nanocrystals using an aerosol spray method to prepare nanostructured mesoporous composites for electrochemical energy storage. The designed composite architectures show high conductivity and hierarchically structured mesopores, which achieve rapid electron and ion transport in electrodes. Therefore, as-synthesized carbon nanotube/TiO2 electrodes exhibit high rate performance through rapid Li(+) intercalation, making them suitable for ultrafast energy storage devices. Moreover, the synthesis process provides a broadly applicable method to achieve the heteroassembly of vast low-dimensional building blocks for many important applications.

A novel three-dimensional (3D) composite based on reduced graphene oxide (rGO)/Fe2O3 was prepared by a one-pot hydrothermal method. Fe2O3 nanoparticles were either attached on the surface of graphene sheets or coated uniformly in the graphene sheets. The resulting composite is found to self-assemble to form a 3D network via hydrothermal treatment. Our results indicate that the as-prepared Fe2O3 nanoparticles show a porous morphology, which results in the rGO/Fe2O3 composites exhibiting excellent microwave absorbing properties in the range of 2–16 GHz and are therefore expected to be a promising candidate as microwave absorbing materials.

Three-dimensional (3D) nanocarbon architectures have attracted great interest in materials science and nanotechnology. In this work, we report the synthesis of a 3D nitrogen-doped graphene nanoarchitecture by using catalytic carbonization of aromatic polyimide (PI) on magnesium oxide (MgO) nanowires. The produced porous graphene nanofibers are crosslinked into an integrated monolithic structure, thereby offering continuous electron conductivity and efficient charge transport. Moreover, nitrogen doping was achieved during the in situ carbonization, enhancing the electronic and interfacial properties of the porous graphene nanofibers. The obtained monolithic frameworks were directly used as binder-free electrodes for lithium batteries, and yield remarkable electrochemical performances, such as high reversible capacity, high rate capability, and superb cycling stability. The monolithic structures can be used as a material platform for the preparation of other functional composites, extending their applications beyond energy storage.

We report a simple approach for fabricating flexible, free-standing, catalytic films composed of graphene oxide/carbon nanotube–Au (GO/CNT–Au) composites by using a one-pot chemical reduction route. The catalyst film was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, thermogravimetric analysis and Raman spectroscopy to investigate the morphology, crystalline structure of the composites. The layered structure of the catalyst film is porous, flexible and exhibits excellent catalytic property in the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) reaction. This study demonstrate here for simple yet effective synthesis of catalyst film with a number of advantages such as good strength, high stability, easy operation, and good reusability with minimal loss of activity.

In this work, we demonstrate that the presence of PdO nanoparticles can significantly enhance the catalytic performance of Pd catalysts for the reduction of 4-nitrophenol (4-NP). Heterogeneous Pd/PdO nanoparticles supported on an oxidized multi-walled carbon nanotube (OCNTs) catalyst is prepared by a one-pot gas-liquid interfacial plasma (GLIP) method with the precursor Pd(NO3)(2)center dot 2H(2)O. The Pd/PdO catalysts with uniform size distribution exhibit remarkable catalytic activity during the reduction of 4-NP to 4-aminophenol (4-AP) in neat water at room temperature. The turnover frequency (TOF) value is up to 750 h(-1), which shows much higher catalytic activity than single Pd nanoparticles supported on OCNTs. Our results indicate that the Pd/PdO catalyst can be readily recovered and reused 10 times.

Nanostructured Li 4 Ti 5 O 12 /CNT composite particles were synthesized using an aerosol spray drying process followed by thermal annealing. After assembling into CNT networks, lightweight, flexible and binder-free Li 4 Ti 5 O 12 /CNT anodes were fabricated for lithium-ion batteries. Electrodes fabricated from these nanocomposites showed effective electron and ion transport and, more importantly, more robust structure compared to traditional binder-bonded electrodes. The electrodes delivered a high reversible capacity and superior rate performance up to an extremely high rate of 100C. Moreover, ultralong cycling stability was attained through 8000 rapid charge-discharge cycles with 89% capacity retention. These results demonstrate the feasibility of ultrafast batteries.

Rational design of electrode materials is essential but still a challenge for lithium-ion batteries. Herein, we report the design and fabrication of a class of nanocomposite architecture featured by hierarchically structured composite particles that are built from iron oxide nanocrystals and carbon nanotubes. An aerosol spray drying process was used to synthesize this architecture. Such nanoarchitecture enhanced the ion transport and conductivity that are required for high-power anodes. The large volume changes of the anodes during lithium insertion and extraction are accommodated by the particle's resilience and internal porosity. High reversible capacities, excellent rate capability, and stable performance are attained. The synthesis process is simple and broadly applicable, providing a general approach toward high-performance energy storage materials.

Reliability of electron and ion transport pathways is one of the most essential criteria that govern cycling stability of lithium-ion battery devices. Herein, crosslinked CNT/V2O5 composite electrodes were fabricated using a chemical coupling method between their interfacial contacts. The crosslinked electrodes show a mechanical strength of ~4.8 MPa, and have stable performance during long-term charge–discharge cycles. The results suggest the importance of forming a crosslinked structure to enhance electrode stability. Keywords: Lithium-ion battery, Carbon nanotube, Crosslinking strategy, Stable electrode