One-step in situ synthesis and characterization of W₁₈O₄₉@carbon coaxial nanocables

Abstract

We demonstrate here in situ synthesis of bulk yield W 18 O 49 @carbon coaxial nanocables based on an easily controlled chemical vapor deposition process at relatively low temperature (760 C) using metallic tungsten powder and ethylene (C 2 H 4 ) as the raw materials. Transmission electron microscope (TEM), energy dispersive x-ray (EDX), and x-ray diffraction (XRD) analyses indicate that the resultant nanostructures are composed of single-crystalline W 18 O 49 nanowires, coaxially covered with amorphous carbon walls. A vapor-solid (VS) mechanism is proposed to interpret the formation of the nanocables. The effect of carbon sources on the nanocable growth was investigated. The results revealed that the introduction of carbon species not only causes the production of W 18 O 49 @C nanocable structures, but also obviously modulates growth behaviors and core/shell diameter ratio of the nanocables. The obtained nanocables may find great applications in catalyst systems and optical and electronic nanodevices because of their enhanced surface properties and in high chemical stabilities.

Synthesis Attempt and Structural Studies of Novel A2CeWO6 Double Perovskites (A2+ = Ba, Ca) in and outside of Ambient Conditions

“…A previously mentioned component, hosting W 5+ ions, could be made according to the recipe from the articles. − W 18 O 49 has the best 4+/5+ ratio of ions in the whole WO 3– x family. Also known as WO 2.72 , made by Fita-Chala et al, it has the best properties according to our experience.…”