GO-based nanocomposites with WPA and PTCDA for application in electrochemical supercapacitors

Abstract

Graphene oxide (GO) based nanocomposites, modified with 15 wt.% 12-tungstophosphoric acid and 3,4,9,10-perylenetetracarboxylic dianhydride, were investigated in this study to evaluate the effect of hydrothermal treatment at 180 °C for 1, 4, 8, and 12 hours on their potential for electrochemical energy storage. Structural and chemical changes were examined using FTIR, XPS, XRD, and temperature-programmed desorption (TPD), while morphological characte- ristics were studied via SEM and TEM. Prior HTT treatment, the FTIR revealed bands of major oxygen groups of GO and confirmed the incorporation of component incorporation. The XPS method has shown a reduction of oxygen-containing groups after HTT, with epoxides being dominantly removed. XRD showed changes in crystallinity and interlayer spacing. TPD method, beside desorption profiles of pristine GO and WPA, revealed significant increase of desorbed groups after HTT and corresponding changes in the TPD spectra. SEM analysis showed transformation of GO layered morphology into hierachically ordered porous structure after HTT. PTCDA was observed both on and within the GO and GO/WPA matrix, thus increasing microstructural complexity. TEM imaging revealed integration of PTCDA into GO matrix on the nanoscale, probably via π-π stacking and hydrogen bonding, while WPA formed nanostructured deposits on edges and basal plane of GO. After 8 hours of HTT, hierarchical structuring of the nanocomposites was evident and corresponded with improved electrochemical performance. Cyclic voltammetry revealed the highest specific capacitance of ~300 F/g for GO/PTCDA, attributed to enhanced surface functionality and morphostructural features. These findings support the further development of rational design of GO-based materials for advanced supercapacitor applications.