Longqiang Wang

Mechanical ball-milling preparation of mass sandwich-like cobalt–graphene nanocomposites with high electrochemical hydrogen storage ability

Mass pure sandwich-like (hcp- and fcc-) Co/GE (graphene)/Co nanocomposites have been synthesized by direct ball-milling of Co and GE powders by adjusting the reaction conditions, and the maximum hydrogen storage capacity achieved was 899.5 mA h g−1 (3.29 wt% hydrogen).

One-pot hydrothermal synthesis of heterostructured ZnO/ZnS nanorod arrays with high ethanol-sensing properties.

ZnO/ZnS heterostructured nanorod arrays with uniform diameter and length were synthesized from zinc substrates in a one-pot procedure by using a simple hydrothermal method. Structural characterization by HRTEM indicated that the heterostructured nanorods were composed of parallel segments of wurtzite-type ZnO and zinc-blende ZnS, with a distinct interface along the axial direction, which revealed the epitaxial relationship, ZnO (1010) and ZnS (111). The as-prepared ZnO/ZnS nanorods showed only two green emissions at around 523 nm and 576 nm. We also found that the nanorods exhibited high sensitivity to ethanol at relatively low temperatures, owing to their smaller size and structure.

Mechanical ball-milling preparation of fullerene/cobalt core/shell nanocomposites with high electrochemical hydrogen storage ability.

The design and synthesis of new hydrogen storage nanomaterials with high capacity at low cost is extremely desirable but remains challenging for todays development of hydrogen economy. Because of the special honeycomb structures and excellent physical and chemical characters, fullerenes have been extensively considered as ideal materials for hydrogen storage materials. To take the most advantage of its distinctive symmetrical carbon cage structure, we have uniformly coated C60s surface with metal cobalt in nanoscale to form a core/shell structure through a simple ball-milling process in this work. The X-ray diffraction (XRD), scanning electron microscope (SEM), Raman spectra, high-solution transmission electron microscopy (HRTEM), energy-dispersive X-ray spectrometry (EDX) elemental mappings, and X-ray photoelectron spectroscopy (XPS) measurements have been conducted to evaluate the size and the composition of the composites. In addition, the blue shift of C60 pentagonal pinch mode demonstrates the formation of Co-C chemical bond, and which enhances the stability of the as-obtained nanocomposites. And their electrochemical experimental results demonstrate that the as-obtained C60/Co composites have excellent electrochemical hydrogen storage cycle reversibility and considerably high hydrogen storage capacities of 907 mAh/g (3.32 wt % hydrogen) under room temperature and ambient pressure, which is very close to the theoretical hydrogen storage capacities of individual metal Co (3.33 wt % hydrogen). Furthermore, their hydrogen storage processes and the mechanism have also been investigated, in which the quasi-reversible C60/Co↔C60/Co-Hx reaction is the dominant cycle process.

Epitaxial growth route to crystalline TiO2 nanobelts with optimizable electrochemical performance.

Anatase TiO(2) nanobelts with 13 nm in thickness have been successfully synthesized via an epitaxial growth chemical transformation, in which the primary H(2)Ti(3)O(7) nanobelt frameworks can be preserved. The phases, crystal structures, morphologies, and growth behavior of both the precursory (Na(2)Ti(3)O(7) and H(2)Ti(3)O(7)) and resultant products (TiO(2)) are characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and selected area electron diffraction (SAED). Detailed investigation of the formation mechanism of the TiO(2) nanobelts indicates epitaxial nucleation and oriented growth of textured TiO(2) inside the nanobelts. TiO(2) nanocrystals prefer certain epitaxial growth direction due to the structural matching of (110)(H2Ti3O7)//(101)(TiO2). We demonstrated that the initial reversible capacity of these TiO(2) nanobelts attained 225 mA h/g. Furthermore, the nanobelts exhibit high power density along with excellent cycling stability in their application as hybrid electrochemical cells.

Cadmium hydroxide nanowires – new high capacity Ni–Cd battery anode materials without memory effect

Cd(OH)2 nanowire anode materials without memory effect were prepared, which had also excellent capacity and stability and reduced at least 80% discharging of toxic heavy metal Cd pollutant to environment under identical capacity conditions.

One Pot, Two Phases: Individual Orthorhombic and Face-Centered Cubic ZnSnO3 Obtained Synchronously in One Solution

Many modern technologies rely on the functional materials that are subject to their phase purity. The topic of obtaining pure crystals from the concomitant allotropes is ever before the eyes of numerous researchers. Here we adopt a template-inducing route and obtain the isolated allotropes located in the appointed regions in the same reaction system. As a typical example, well-defined individual face-centered cubic and orthorhombic ZnSnO3 crystals were successfully synthesized assisted by a ZnO inducing template or without it in an identical solution, respectively. And the different growing mechanisms of the ZnSnO3 allotropes were also proposed, which takes a pivotal step toward the realization of allotropes dividing. Moreover, the two individual pure-phased ZnSnO3 allotropes obtained in one reaction system exhibit porous microspherical morphologies constructed by the tiny nanograins, resulting in their high sensitivities to ethanol with fast response and recovery and good selectivity and stability.

Ultrasonochemical-assisted synthesis of CuO nanorods with high hydrogen storage ability

Uniform CuO nanorods with different size have been synthesized in a water-alcohol solution through a fast and facile ultrasound irradiation assistant route. Especially, the as-prepared CuO nanorods have shown a strong size-induced enhancement of electrochemical hydrogen storage performance and exhibit a notable hydrogen storage capacity and big BET surface area. These results further implied that the as-prepared CuO nanorods could be a promising candidate for electrochemical hydrogen storage applications. The observation of the comparison experiments with different concentrations of NaOH, ethanol, CTAB, and HTMA while keeping other synthetic parameters unchanged leads to the morphology and size change of CuO products.