Structural and Morphological Studies of Bi₂O₃/MWCNTs Doped Reduced Graphene Oxide for Energy Storage Applications

Abstract

Bismuth oxide (Bi2O3), multi-wall carbon nanotubes (MWCNTs), reduced graphene oxide (rGO), and its composite were synthesized by modified Hummers method followed by chemical and thermal reduction processes. During synthesis, graphene oxide (GO) was reduced to rGO and decorated evenly with Bi2O3 and CNTs. Average crystallite size of graphite flakes (GF), GO, rGO, rGO/Bi2O3, rGO/CNTs, and rGO/Bi2O3/CNTs is calculated from XRD profiles using the Scherer equation are 77.75, 11.91, 1.79, 18.1, 21.05 and 18.05 nm, respectively. In XRD, deconvolution of rGO/Bi2O3/CNTs, C60 and C70 diffraction peaks were observed. The morphology of rGO/Bi2O3/CNTs have smoother surface similar to GO, rGO, rGO/Bi2O3, and rGO/CNTs except GF, was revealed in SEM images. HR-TEM analysis revealed carbon (002) in rGO with d-spacing of 0.34 nm, Bi (102) with d-spacing of 0.31 nm and MWCNTs on 2 nm scale. Bonding of Bi2O3 and CNTs with graphene layers led to the formation of novel functionalized nanocomposite which enhances electrical conductivity of rGO. Using AFM images of rGO/CNTs films thicknesses, arithmetic mean, and RMS roughness were estimated as 6 nm at 14.91 nm and 19.27 nm, respectively. Results of rGO/Bi2O3/CNTs revealed that with the small crystallite size, functionalization and nanoscale roughness could be promising for energy storage applications.