A method to coat the surface of ultrafine particles by an amorphous carbon layer was developed and a characteristic reduction of the ultrafine particles has been observed for WO3 ultrafine particles. The carbon layer formation and the reduction process have been observed in situ in a transmission electron microscope. The growth of the carbon layer predominately occurred upon heating at 200°C by using a heating stage. The characteristic graphitization of the carbon layer took place at about 400°C. The characteristic gap formation at the interface of the carbon layer and WO3 particles started at about 400°C. The reduction indicates that a reaction between O and C atoms occurred and CO or CO2 gas evaporated into vacuum during the observation. The WO3 particles with the gap between carbon layers were also reduced.
|Number of pages||8|
|Journal||Physics of Low-Dimensional Structures|
|Publication status||Published - 2002 Jan 1|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Physics and Astronomy (miscellaneous)