APPARATUS
Powder XRD (Rigaku Ultima IV Powder X-Ray Diffractometer instrument
equipped with a CuKα) and Raman spectroscopy (Jobin Yvon Horiba
LabRam, HR800 laser sources with a λ=532 nm) were used for structural
determination. The optical band gap energy was determined using UV-VIS
analysis (Shimadzu UV-1800). Simultaneous TG-DTA data was collected at
10 oC min-1 heating rate under a
nitrogen gas flow of 150 ml min-1 in an Alumina pan.
RESULTS AND DISCUSSION
4.1 Powder XRDXRD spectrum of BZC and BZC/rGO is depicted in Figure 1. The XRD
patterns of BZC were compared with that reported for Ba-based perovskite
oxides.22 Major XRD peaks are obtained between 2θ=20
to 50 o position. The Scherrer formula
(D=Kλ/β Cosθ),23 was used to the
calculated crystalline size of the BZC and BZC/rGO. Where K is
the constant (value=0.9). β, θ, D, and λ represents
full-width-at-half-maxima, Bragg’s angle (2θ/2), size of the particle
(nm), and wavelength (0.154 nm for Cu-Kα source), respectively. The
crystalline size of BZC, and BZC/rGO was between 10-20 nm, confirming
its nanosize. Both, BZC, and BZC/rGO exhibit similar XRD patterns.
Figure 1. XRD Spectrum of BZC and BZC/rGO
4.2 Raman analysisRaman spectrum of BZC and BZC/rGO is given in Figure 2. The Raman
spectrum of BZC exhibits a total of five peaks that appear between
200-700 cm-1 with a Raman shift value of
~206, 281, 326, 430, and 694 cm-1,
respectively. The presence of peaks at these Raman shift values confirms
the formation of perovskite-type BZC as reported by Chamorro et
al.24 The composite addition of BZC/rGO composite
exhibits similar peaks, however, the Raman bands between 200-500
cm-1 were shifted to higher Raman shift region (blue
shift, Figure 2) compared to BZC. Blueshift in BZC incorporating rGO
could be because of a change in the chemical bond or interatomic bond
force of the corresponding peak, as well as electron cloud
movement.25 Disappearance of peak ~430
cm-1 in case of BZC/rGO composite could be because of
the change in the bonding interaction of rGO with ZCB.
Figure 2. Raman Spectrum of BZ and BZC/rGO