2.4. Characterisation
Transmissionelectronmicrographswereobtainedfrom
a transmissionelectronmicroscopy(TEM,PhilipsFEI
CM12) systemandtheparticlesizewasmeasuredusing
analySISDocuVersion3.2imageprocessingsoftware.
A field-emissionscanningelectronmicroscopeequipped
with energy-dispersiveX-ray(EDX)(FE-SEM,Quanta
FEG450) wasusedtoanalysethesilicaparticles.TheN2
adsorption/desorptionisothermsweremeasuredbyan
automaticsurfaceareaandporesizeanalyser(Quantacer-
ome AUTOSORB-1)at77K.Thespecificsurfaceareawas
determined byusingBETequation.Asinglepointtotal
pore volumewasestimatedastheliquidvolumeofN2
adsorbed atarelativepressureof0.1and0.97,respec-
tively. AFourierTransformInfrared(FTIR)spectrum
(Perkin-Elmer2000)wasobtainedfromapelletcomposed
of amixtureofsampleandspectroscopic-gradeKBrata
mass ratioof 1/100 thatwasanalysedoverthewave
number rangeof4000–400cm1. X-raydiffraction(XRD)
patterns wereobtainedfromanX-raydiffractometer
(Philip ElectronicInstruments)usinganaccelerationvol-
tage of30kVandacurrentof160mA.Thediffraction
angle wasscannedfrom101 to 801 2y at 81 min1.