Rong Yang

Morphology‐Controlled Synthesis of SnO2 Nanotubes by Using 1D Silica Mesostructures as Sacrificial Templates and Their Applications in Lithium‐Ion Batteries

SnO(2) nanotubes with controllable morphologies are successfully synthesized by using a variety of one-dimensional (1D) silica mesostructures as effective sacrificial templates. Firstly, 1D silica mesostructures with different morphologies, such as chiral nanorods, nonchiral nanofibers, and helical nanotubes, are readily synthesized in aqueous solution by using the triblock copolymer Pluronic F127 and the cationic surfactant cetyltrimethylammonium bromide as binary templates. Subsequently, the obtained 1D silica mesostructures are used as sacrificial templates to synthesize SnO(2) nanotubes with preserved morphologies via a simple hydrothermal route, resulting in the formation of well-defined SnO(2) nanotubes with different lengths and unique helical SnO(2) nanotubes with a wealth of conformations. It is revealed that both of the short and long SnO(2) nanotubes showed much better performance as anode materials in lithium-ion batteries than normal SnO(2) nanopowders, which might be related to the hollow structure of the nanotubes that could alleviate the volume changes and mechanical stress during charging/discharging cycling. Moreover, the capacity and cycling performance of short nanotubes, which showed a specific discharge capacity of 468 mAh g(-1) after 30 cycles, are considerably better than those of long nanotubes because of the more robust structure of the short nanotubes.

Plasma-assisted approaches in inorganic nanostructure fabrication.

Plasma is a unique medium for chemical reactions and materials preparations, which also finds its application in the current tide of nanostructure fabrication. Although plasma-assisted approaches have been long used in thin-film deposition and the top-down scheme of micro-/nanofabrication, fabrication of zero- and one-dimensional inorganic nanostructures through the bottom-up scheme is a relatively new focus of plasma application. In this article, recent plasma-assisted techniques in inorganic zero- and one-dimensional nanostructure fabrication are reviewed, which includes four categories of plasma-assisted approaches: plasma-enhanced chemical vapor deposition, thermal plasma sintering with liquid/solid feeding, thermal plasma evaporation and condensation, and plasma treatment of solids. The special effects and the advantages of plasmas on nanostructure fabrication are illustrated with examples, emphasizing on the understandings and ideas for controlling the growth, structure, and properties during plasma-assisted fabrications. This Review provides insight into the utilization of the special properties of plasmas in nanostructure fabrication.

The synthesis and hydrogen storage properties of pure nanostructured Mg2FeH6

In this work, pure nanostructured Mg(2)FeH(6) is successfully synthesized by sintering of a mixture of 2Mg + Fe nanoparticles. The successful preparation of pure Mg(2)FeH(6) can be attributed to the small particle sizes of Mg and Fe nanoparticles prepared by hydrogen plasma-metal reaction (HPMR), which benefits the synthesis. The hydrogen storage properties of Mg(2)FeH(6) and the synthesis mechanism of the Mg-Fe-H system are studied. The sample desorbs 5.0 wt% of hydrogen rapidly in 6 min under an initial hydrogen pressure of approximately 100 Pa at 623 K. The enthalpy and entropy of the reaction are deduced from the equilibrium plateau pressures of the desorption isotherms. The obtained Mg(2)FeH(6) shows favorable hydrogen storage properties due to the specific nanostructure of the materials.

Superior hydrogen desorption kinetics of Mg(NH2)2 hollow nanospheres mixed with MgH2 nanoparticles

Mg3N2 nanocubes were prepared by vaporized bulk magnesium in ammonia atmosphere associated with plasma metal reaction. Then the product transformed to Mg(NH2)2 hollow nanospheres after it was reacted with NH3 based on the Kirkendall effect. The electron microscopy results suggested that the obtained hollow nanospheres were around 100nm and the shell thickness was about 10nm. Because of its short distance for Mg2+ diffusion and large specific surface area for interaction between Mg(NH2)2 and MgH2, the structure dramatically enhanced the hydrogen desorption kinetics of Mg(NH2)2–2MgH2.

Plasma-enhanced chemical vapour deposition of inorganic nanomaterials using a chloride precursor

Plasmas have been widely used for the fabrication of nanomaterials owing to their unique properties in chemical reactions. The plasma-enhanced chemical vapour deposition (PECVD) technique has been applied to produce a large variety of materials. In this perspective, we take a look at the progress made in the research of PECVD using chloride precursors in the last decade. We discuss the advantage of using a plasma compared with the thermal chemical vapour deposition technique and emphasize the special effects of plasma on nanomaterial fabrications in the PECVD technique, including kinetic and thermodynamic effects. We also outline the current challenges for this technique, and attempt to offer our personal opinion on the future applications of the PECVD technique with chloride precursors.

Metal Al produced by H2 plasma reduction of AlCl3: a thermodynamic and kinetic study on the plasma chemistry.

In this paper we reported that low temperature plasma may reverse the direction of a chemical reaction. The thermodynamically forbidden reaction between H 2 and AlCl 3 was able to take place with the assistance of low temperature plasma, yielding metal Al. The plasma chemistry of the reaction was investigated by optical emission spectroscopy, which suggested that the dissociation of H 2 and AlCl 3 molecules by plasma led the reaction to a thermodynamically favorable one by creating reaction channels with low Gibbs free energy change. The addition of Ar promoted the reaction kinetics dramatically, which was attributed to the enhanced dissociation of AlCl 3 molecules by excited Ar species.