3.3 X-ray diffraction of the samples
Fig. 3 showed XRD patterns of MC support, pure TiO2
powder and 50%TiO2/MC composites heat-treated at different
temperatures. Two broad peaks at 24° (2θ) and 43° (2θ) are
characteristic of graphitic crystalline of MC. The pure TiO2
calcined at 450 °C exhibits a mixed crystal structure of
anatase and rutile. It is well known that the calcination
improves the crystallinity of pure TiO2 with increasing
temperature. As a result, the amorphous TiO2 changes to the
anatase phase and further to rutile phase. However, in this
study, the TiO2 deposited on MC calcined still retained the
structure of anatase at the temperatures even up to 750 o
C
without rutile peak. It is therefore suggested that TiO2/MC nanocomposites have a good thermal stability, which could be
ascribed to the high surface area of MC where TiO2
nanoparticles were well dispersed. The interfacial interaction
between TiO2 and MC could restrain the transformation of
TiO2 from anatase to rutile phase