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