Development of pristine and Au-decorated Bi₂O₃/Bi₂WO₆ nanocomposites for supercapacitor electrodes

Pristine and Au-decorated Bi₂O₃/Bi₂WO₆ nanocomposites were synthesized via a facile hydrothermal method. Characterization techniques such as XRD, FESEM, HRTEM and XPS were used to explore the structural, morphological and electronic properties. Furthermore, electrochemical characterizations including cyclic voltammetry (CV), the galvanostatic charge-discharge (GCD) method, and electrochemical impedance spectroscopy (EIS) were performed to investigate the supercapacitance behaviour of the synthesized materials. Interestingly, the Au-decorated Bi₂O₃/Bi₂WO₆ nanocomposite showed a higher capacitance of 495.05 F g^-1 (1 M aqueous KOH electrolyte) with improved cycling stability (99.26%) over 2000 cycles, measured at a current density of 1 A g^-1, when compared to the pristine Bi₂O₃/Bi₂WO₆ composite (capacitance of 148.81 F g^-1 and good cycling stability (95.99%) over 2000 cycles at a current density of 1 A g^-1). The results clearly reveal that the decoration of the Bi₂O₃/Bi₂WO₆ composite with Au nanoparticles enhances its supercapacitance behaviour, which can be attributed to an increase in electrical conductivity, good electrical contact between the electrode and electrolyte, and an increase in effective area. The Au-decorated Bi₂O₃/Bi₂WO₆ nanocomposite can be considered as an electrode material for supercapacitor application.