IR spectra were
recorded on a Bruker IFS-66 FT-IR Spectrophotometer (Billerica, MA,
USA). High angle X-ray diffraction (XRD) patterns were obtained on a
Philips-PW 17C diffractometer with Cu Ka radiation. SEM was
performed by gently distributing the powder sample on the stainless
steel stubs, using SEM (Philips, XL30, Almelo, the Netherlands)
instrument.