Synthesis of Polyaniline Nanotubes decorated with Graphene Quantum Dots: Structural & Electrochemical Studies

Abstract The aim of this paper was to synthesize sulfonated polyaniline nanotubes (s-PANI-NTs) decorated with graphene quantum dots (GQDs) and explore their use as an electrode material in supercapacitors. Spectroscopic (FTIR, Raman, UV-vis, XPS) studies confirmed the presence of both components in the composite, while microscopic (SEM, TEM) analysis proved that the tubular morphological form of PANI was obtained. Moreover, TEM images showed that the decoration of the s-PANI-NT surface with GQDs resulted in the smoothing of the outer part of the polymer wall. Consequently, a higher dispersibility of the s-PANI-NTs/GQDs composite was achieved. A theoretical investigation of the interactions between PANI chains and GQDs was also performed. Furthermore, voltammetric and impedance spectroscopy studies showed that, in the selected concentration range, modification of s-PANI-NTs with GQDs improved the electrochemical properties of the synthesized material. The large BET specific surface area (44.5 m²⋅g−1) and high specific capacitance (245 F⋅g−1) calculated for the optimal s-PANI-NTs/GQDs composite confirmed that the obtained material can be applied in energy storage systems.