Silicon carbide microtubes with medium surface area, 30-70 m(2) g(-1), were
successfully prepared by shape memory synthesis involving the reaction bet
ween SiO vapors and low surface area, 1-2 m(2) g(-1), carbon microfibers. T
he gross morphology of the carbon microfibers was conserved during the carb
urization process. After calcination at 600 degrees C in order to eliminate
the unreacted carbon, hollow SiC microtubes were obtained. The pore size d
istribution of the material was centered around 10 nm, allowing a high acce
ssibility of potential reactants to an active phase during catalytic reacti
ons. The surface was covered by an amorphous layer 3 nm thick, XPS measurem
ents revealed that this amorphous phase was composed of a mixture of SiO2 a
nd SiOxCy. Soda treatment at 80 degrees C allowed complete removal of this
surface phase without any change in the material morphology. A similar resu
lt was also obtained after treatment with an aqua regia medium. (C) 1999 El
sevier Science B.V. All rights reserved.